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Some of the key strategies to save this species are protecting lands with dense forests that are home to fossa.
Getting corridors put into place on new roads being built and on current roads where fossa are frequently observed.
Working with farmers and educating them on the importance of the species and how to deter them away rather than killing them.

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There are many myths and tales told about the fossa among Madagascar villagers. A good number of them center around the conflicts and attitudes that can be seen between the people and the predators. One of the myths is that the scent of the fossa alone can kill poultry. Another claims that in the middle of the night they sneak in and kill babies.

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The fossa is Madagascar's apex predator so it has a significant impact on their prey items. Since fossas are found all across Madagascar's forest they impact a very large area. Without them, we could see significant shifts in populations of their prey items. If their population rises too high or too much they might cause significant ecosystem damage.

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When trying to manage a population that is vulnerable to change you must looks and how building things like roads will impact them. The fossa is already majorly impacted by habitat fragmentation and the construction of roadways will not aid in the already fragmented landscape. This will place a divide between animals and make it hard for them to get to one another for reproduction purposes. One thing that managers could do to help sway this problem is the put corridors in to new and existing roads that may be an obstacle for the fossa.

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Abstract

The global expansion of road networks threatens apex predator conservation and ecosystem functioning. This occurs through wildlife-vehicle collisions, habitat loss and fragmentation, reduced genetic connectivity and increased poaching. We reviewed road impacts on 36 apex predator species and assessed their risk from current roads based on road exposure and species vulnerability. Our findings reveal all apex predators are exposed to road impacts. Eight of the ten species with the highest risk occur in Asia, although other high-risk species are present in the Americas, Africa and Europe. The sloth bear suffers the highest risk of all apex predators, followed by the tiger and dhole. Based on species risk from roads, we propose a widely applicable method to assess the potential impact of future roads on apex predators. We applied this method to proposed road developments in three areas: the Brazilian Amazon, Africa, and Nepal, to locate high-impact road segments. Roughly 500 protected areas will be intersected by these roads, threatening core apex predator habitats. We advocate the need for rigorous road development planning to apply effective mitigation measures as an urgent priority and to avoid construction in wilderness areas and predator strongholds.

Introduction

Roads are the most widespread form of landscape modification, developed in pursuit of natural resource exploitation, agricultural, and economic development. They commonly drive loss of ecological health and integrity3,4 providing human access to otherwise undisturbed areas and affecting ecosystems and wildlife3. Some of the impacts of roaded landscapes for wildlife are direct mortality from wildlife-vehicle collisions (WVC), land clearing driving habitat loss and fragmentation, reduced habitat quality adjacent to roads, increased access for poaching, and barriers to wildlife movement causing population fragmentation and loss of genetic connectivity4,5.

Roads affect almost all species groups4, but apex predators are acutely threatened by road development, due to their large spatial ranges, low population densities, low reproductive rates, and intolerance to increased human disturbance for most species6. Apex predators are defined here as non-herbivorous terrestrial mammals having an average body mass higher than 13 kg7, or species that are below that threshold but are main predators in their ecosystems (see Supplementary Table S1). They are simultaneously vital to the structure, functioning, and resilience of ecosystems globally8,9, due to their direct and indirect influence on the interactions of lower trophic levels, by displacing mesopredators and regulating large herbivore populations8. The maintenance of ecosystem functioning provided by apex predators is linked to a variety of ecosystem services, including carbon sequestration, water provision, and food security9,10. Therefore, conservation of apex predators and their habitats is exceptionally important to ensure the preservation and functionality of entire ecosystems over time8.

Historically, road development has been pervasive in developed countries with high Gross Domestic Product (GDP), such as Northwest Europe and the USA, as well as in more densely populated countries like India and Bangladesh11. Large infrastructure projects such as the Belt and Road Initiative12, and Africa's Development Corridors have provided the impetus to shift this trend. Over 25 million km of newly paved roads will be constructed globally by 205013. Around 90% will occur in developing nations that host critical ecosystems and rich biodiversity areas14 important for apex predators, such as the Amazon15, Africa16 and Southern Asia17. It is essential to establish a deeper understanding of the impact of current and proposed roads on apex predators. This knowledge can form the base for meaningful engagement between road planning committees, financiers, and local stakeholders to ensure biodiversity is protected while achieving the maximum social and economic benefit.

Here, we aim to assess the risk of terrestrial apex predator species from current road infrastructure and to detect impact areas of proposed road development on apex predators. We specifically: (1) conducted a systematic literature review and curated a global database of WVC to present the state of knowledge of the impact of roads on apex predators; (2) evaluated the risk to roads of 36 apex predators globally, considering the level of road exposure and the vulnerability of predators; and (3) predicted the level of impact of three future road developments by overlying the risk to roads of predators and protected areas (PAs). We used three case studies that hold critical ecosystems for apex predator diversity and where plans for road development have been proposed: the Brazilian Amazon road network expansion, development corridors in the African continent, and the completion of the Postal Highway in Nepal.

Current knowledge of road impacts on apex predators

Wildlife-vehicle collisions (WVC)

The most direct impact of roads on apex predators is WVC resulting in death or injury6. We show evidence of almost all apex predators being impacted by WVC (Supplementary Fig. S1), with documented roadkill data for 30 of the 36 species (Supplementary Dataset 1). While it is expected that WVC are most common in areas with a combination of high predator richness (Fig. 1A) and high road density (Fig. 1B), detection is also dependent on WVC monitoring effort (Fig. 1C, D). Evidence is, thus, biased to species in countries with high road density and strong WVC monitoring effort. Indeed, such impacts were observed in Brazil, the USA, Canada, Spain and South Africa (Fig. 1). Per year, road accidents impact more than 100 individuals of American black bear ( Ursus americanus) in the USA, maned wolf ( Chrysocyon brachyurus), puma ( Puma concolor) and ocelot ( Leopardus pardalis) in Brazil, serval ( Leptailurus serval) in South Africa, and Iberian lynx ( Lynx pardinus) in Spain (Supplementary Fig. S1). East Africa shows a relatively high WVC incidence despite limited monitoring effort and lower density of roads, likely due to the region's high apex predator richness (Fig. 1). Nevertheless, large gaps in documented WVC incidents exist in Southeast Asia, tropical America, and West and Central Africa (Fig. 1C). Moreover, WVC data is mainly missing for species distributed in Southeast Asia, such as clouded leopard ( Neofelis nebulosa), Sunda clouded leopard ( Neofelis diardi), sun bear ( Helarctos malayanus) and Asiatic golden cat ( Catopuma temminckii).

( A) Global apex predator richness ( n = 36) calculated from IUCN species distribution maps18. ( B) Global road density at 5-arcmin resolution, equivalent to approximately 8 km in the tropics, representing four road types (highways, primary, secondary, and tertiary roads), data from the Global Roads Inventory Project11. ( C) Total number of Wildlife-Vehicle Collisions (WVC) of apex predators recorded in a single year (between 1963 and 2021) for each country with available WVC data. ( D) WVC sampling effort per country, referred to the sum of years of study (ranging from 1963 to 2021). Maps were generated in R software v4.0.3 ( https://www.R-project.org/).

WVC are a particularly serious threat for apex predators as they have small population sizes frequently in contact with roads due to wide home-ranges, such as the Iberian lynx and the Asiatic cheetah ( Acinonyx jubatus venaticus)19,20. In total, 229 WVC incidents involving Iberian lynx were documented between 1990 and 2020 (Supplementary Dataset 1). Likewise, for the critically endangered Asiatic cheetah, the death of one to two individuals annually (Supplementary Dataset 1) poses a significant threat to the survival of the population20. Factors such as road location and vehicle speed greatly influence the magnitude and severity of WVC incidents. For instance, the Iberian lynx encounters more collisions on roads bisecting its preferred habitat, and with a speed limit greater than 90 km/h19. Road proximity to PAs also influences collision frequency, especially when such areas maintain healthy predator populations20. For example, in Iran, the highest number of road collisions for the Asiatic cheetah was reported in highways crossing PAs20.

Habitat loss and fragmentation

Roads are key drivers of human development and land-use conversion, causing habitat loss and degradation3. As roads divide habitats into progressively smaller patches, remaining natural areas become fragmented, restricting predator population connectivity21. Due to their need for large, undisturbed areas to support viable populations, apex predators are disproportionately affected by discontinuous habitat6. These effects are further intensified for species with small distributions or highly specialized habitat requirements21. For instance, the spectacled bear ( Tremarctos ornatus), which inhabits the northern Andes in South America, is confined to patches of montane forest and grassland fragmented by roads22. Furthermore, linear infrastructures also disrupt the behaviour and distribution of prey species potentially impacting apex predators through a reverse trophic cascade in accordance with the resource dispersion hypothesis23.

Genetic fragmentation

Roads drive loss of genetic diversity through direct reduction of population sizes caused by WVC mortality, and through creating physical barriers to movement, affecting population connectivity and ultimately resulting in isolation24. High mobility predators are particularly susceptible, as seen with bobcat ( Lynx rufus) and coyote ( Canis latrans) in California, and Grizzly bear ( Ursus arctos) in western North America, which show spatial population structuration and genetic differentiation in relation to roads25,26. Moreover, freeways in California present complete barriers to puma movement, causing inbreeding in isolated subpopulations27. Likewise, populations of the ocelot in southern Texas suffer from alarmingly low genetic diversity due to extensive road development28. The consequences of roads in determining genetic structure are not always well documented, in part due to the relatively short period over which populations have been influenced by roads24. Still, a strong negative impact is expected in the future years29,30. Reduced genetic variability leading to a higher probability of extirpation is predicted for tiger ( Panthera tigris) and Asiatic Black bear ( Ursus thibetanus) populations in Asia29,30. Therefore, it is essential that roads do not pose absolute barriers to gene flow, allowing some individual crossing for genetic exchange24,25.

Poaching and hunting

Transport infrastructure promotes human settlements and increases access to formerly remote wilderness areas, facilitating poaching for bushmeat and illegal wildlife trade31. Examples are found in Southeast Asia, where roads contribute to poaching in roadside forests and road networks facilitate illegal animal trade32. In India, poachers use rail routes to access tiger habitats33. The same is also reported in South America, where hunting effort is demonstrably higher near roads within PAs in the Ecuadorian Amazon34. Likewise, in continental Africa, snare density increases with decreasing distance from roads35,36. Consequently, large carnivore populations have significantly declined in heavily hunted areas31. In the Congo Basin, extensive bushmeat hunting led to a decline in leopards ( Panthera pardus)37. Similarly, jaguar ( Panthera onca) density decreased due to the extirpation of their prey when accessibility through roads increased in the Amazon forest38. The depletion of prey can also lead to human-wildlife conflicts as predators are likely to rely on livestock and anthropogenic food39.

Road risk on apex predators

Here we assess the risk of the current road network on apex predators based on exposure to roads and vulnerability of species (Supplementary Table S2). Our analysis highlights that all apex predator species are currently exposed to the global road network. However, the level and severity of their risk to roads varies widely (Fig. 2). With the notable exception of Iberian lynx, African wild dog ( Lycaon pictus), lion ( Panthera leo), and Ethiopian wolf ( Canis simensis), more than half of the distribution of apex predator species occur outside of PAs (Fig. 2), where road development is less restricted3,40. Currently, the dhole ( Cuon alpinus), tiger, Sunda clouded leopard and striped hyena ( Hyaena hyaena) are not listed as threatened by transport infrastructures according to IUCN red list assessment18, however, our results clearly show that these species are among the top eight predators most at risk from roads. On the other hand, species restricted to high latitudes: Canadian lynx ( Lynx canadensis) and wolverine ( Gulo gulo), experience a lower risk from roads compared to other apex predators due to larger areas of natural habitat and lesser road density in boreal landscapes (Fig. 1B and Supplementary Fig. S2).

Apex predators risk to roads calculated as the product of exposure to roads (road density within the species range) and vulnerability of species. Gauges indicate the risk value of each species. Bars indicate the standardized road density, the proportion of species distribution area unprotected, standardized number of IUCN listed threats, and standardized value of the categorized average body mass (i.e., very large (> 100 kg), large (25-100 kg), medium (15-25 kg), small (8-15 kg)). The IUCN conservation of each species18 is shown. P. uncia, L. pictus and L. canadensis silhouettes were drawn by Gabriela Palomo-Muñoz, all predator silhouettes were acquired from PhyloPic ( http://phylopic.org/).

Asia is a hotspot of high-risk apex predators, hosting eight of the ten species most exposed to roads: the sloth bear ( Melursus ursinus), tiger, dhole, Asiatic black bear, clouded leopard, sun bear, Sunda clouded leopard and leopard (Fig. 2). Indeed, the sloth bear is the most affected apex predator of all assessed species. Distributed in the Indian subcontinent, where roadless areas are almost nonexistent (Fig. 1B), the sloth bear has the highest road density among all species (303 m/km ² on average; Fig. 2) and almost 97% of its distribution is covered by roads (Supplementary Fig. S2). This high exposure significantly contributes to habitat fragmentation and increased mortality from vehicle collisions. From 2012 to 2017, 15 sloth bear roadkills were recorded in India (Supplementary Dataset 1); this level of mortality presents a serious threat for this species41. Previous studies have also highlighted the large-scale impact of roads on tiger42 and Asiatic black bear43. The dhole experiences the second highest road density (202 m/km ²), followed by the tiger, Asiatic black bear, clouded leopard, sun bear and Sunda clouded leopard with road densities ranging from 160 m/km ² to 140 m/km ² (Supplementary Fig. S2). The latter two of these species occur in Borneo, where road density has increased due to logging for oil palm and timber plantations during the last four decades44.

The leopard and striped hyena also show high risk (Fig. 2). While they occur in Africa and Asia, Asian populations are more exposed to roads than those in Africa (Supplementary Fig. S2), especially in areas of South Asia where road density is extremely high (Fig. 1B). Among the species restricted to Africa, the brown hyena ( Parahyaena brunnea) which is endemic to Southern Africa, is the predator most at risk (Fig. 2). This species is also the most exposed to roads (average road density 142 m/km ²) mostly due to the expanded infrastructure development in South Africa (Supplementary Fig. S2). The fosa ( Cryptoprocta ferox) follows in the level of risk (Fig. 2). Endemic to Madagascar, its habitat is heavily fragmented45 and 87% of its area is unprotected (Fig. 2).

In the Americas, two of the species with higher risk occur in South America: the spectacled bear and maned wolf (Fig. 2). The spectacled bear is restricted to the northern Andean mountain chain where most of the infrastructure development in western South America has occurred (Fig. 1) and as a consequence, its distribution is highly fragmented22. The maned wolf inhabits open habitats where agricultural expansion in conjunction with linear infrastructure has commonly occurred, therefore most of its distribution is covered by roads (average road density of 128 m/km ²; Supplementary Fig. S2). This canid suffers excessive WVC (Supplementary Fig. S1), mostly in the Brazilian cerrado, leading to a high extinction risk of local populations41. Another high-risk predator in the Americas is the Puma (Fig. 2). Despite its wide distribution, from Canada to the south of the Andean mountain chain, roadless areas only occur in the Amazon basin and North America (Supplementary Fig. S2), resulting in a high average road density within its range (125 m/km ²). Moreover, this predator has already been assessed as highly vulnerable to roads43.

North America and Europe host three of the most affected apex predators: bobcat, red wolf ( Canis rufus) and Iberian lynx (Fig. 2). The bobcat occurs widely across North America18 and is more exposed to roads compared to red wolf (Supplementary Table S2), however, the red wolf is critically endangered due to its restricted distribution to south-eastern United States18. As the Iberian lynx distribution is restricted to the Iberian Peninsula, inherently its exposure to roads is very high with an average road density of 162 m/km ² (Supplementary Fig. S2). Most of the Iberian lynx distribution (66%) is now protected (Fig. 2) and vast conservation interventions are in place19, but roads still constitute an important threat to the population43.

Our assessment is global, therefore underestimation of road impacts on widely distributed species is likely to happen. Threats for local populations may not be immediately evident, as those reported for the jaguar in the Brazilian Atlantic forest46, Asiatic cheetah in Iran20, or Floridian subspecies of black bear ( Ursus americanus floridanus) and Puma ( Puma concolor conyi) which are acutely threatened by WVC (Supplementary Dataset 1). Moreover, although species such as the grey wolf ( Canis lupus) show a lower risk to roads due to their inhospitable northern distribution, populations found in the lower latitudes still incur a high impact from roads in the form of WVC (Supplementary Fig. S1). Thus, local circumstances must be taken into consideration to assess the vulnerability of populations and to conserve species at the local and regional levels.

Future road development case studies

Here, we evaluate the potential impact of proposed road development on apex predators for each of the case studies based on the calculated cumulative road risk on apex predators (Fig. 3). Our case studies extend from specific areas to continents, where a great diversity of top predators occur: the Brazilian Amazon, the African continent, and Nepal.

Cumulative road risk of apex predators globally used for predicting the potential impact of future roads. The cumulative risk is based on the aggregation of the road risk for each species and the presence of protected areas (see Methods), calculated at 5-arcmin resolution. Blue boxes indicate the three case studies used for assessing the potential impact of future road developments in ( A) the Brazilian Amazon, ( B) Africa, and ( C) Nepal. Maps were generated in R software v4.0.3 ( https://www.R-project.org/).

Brazilian Amazon

Due to the historical use of rivers for transport47, the Brazilian Amazon is currently one of the world's largest road-free areas11. Road construction in the Amazon basin began in the 1950s47, but development has been intermittent. Proposed road expansion in the Brazilian Amazon includes roughly 16,700 km of new roads and paving a further 19,800 km of existing dirt roads (Fig. 4A). Of these, 24 projects are considered national priorities, totalling 6,032 km and mainly consisting of upgrading dirt roads15.

Potential impact of future road developments in ( A) the Brazilian Amazon, ( B) Africa, and ( C) Nepal. Bubble sizes indicate the percentage of road length under each level of impact. Green areas denote protected areas48, and in darker green are the areas that will be intersected directly or within a 10-km buffer around proposed roads. Bar graphs indicate the potential impact of future road developments on predator species present in ( D) the Brazilian Amazon, ( E) Africa, and ( F) Nepal. Bars on the left show the length (km) of future roads that will cross the species distribution range; numbers beside the bars indicate the percentage in relation to the complete length of the future development. Bars on the right indicate the proportion of future road length crossing the species range in relation to the size of the species total distribution. FRL = Future Road Length. Colours in bars represent the road risk for each species calculated in our assessment. Maps were generated in R software v4.0.3 ( https://www.R-project.org/). L. pictus silhouette was drawn by Gabriela Palomo-Muñoz, all predator silhouettes were acquired from PhyloPic ( http://phylopic.org/).

Future road development will have a high and ubiquitous impact on top predators in the Brazilian Amazon, with 85% of future roads having a level of impact between 3 and 5 (out of 10) (Fig. 4A). Although the impact may appear moderate due to the lower diversity of apex predators in the Amazon (Fig. 1A), all proposed roads will strongly affect apex predator populations across the entire Brazilian Amazon (Fig. 4 A).

Almost all 36,500 km of future roads will be built inside the distribution ranges of puma (99.8% of the total road length), ocelot (99.1%) and jaguar (72.1%) (Fig. 4D). Due to their affinity for closed-canopy forests, the Amazon basin is a stronghold for the jaguar and the ocelot18,49. Thus, relative to the size of their respective ranges, these species will be the most impacted by the proposed roads (Fig. 4D). With large roadless areas in the Amazon, the jaguar and ocelot do not show an alarming risk from the current road network compared to other predators (Fig. 2). However, they are currently heavily impacted by WVC (Supplementary Fig. S1) and their risk to roads will likely increase with future developments. The puma will be less affected due to its wider range outside the region, but the Amazon rainforest remains critical for their conservation18. The maned wolf is the eighth predator most at risk from current road infrastructure (Fig. 2). However, it appears as the least impacted in our future road assessment because it inhabits open landscapes which scarcely occur in the Amazon50.

More than one third (38.7%) of the roads will be built inside 175 PAs, including indigenous lands and sustainable use reserves (Fig. 4A). The Yanomami indigenous territory will be significantly impacted with 1,620 km of roads crossing it. More than 700 km of new roads will bisect the largest national park in Brazil -Tumucumaque Mountains- and Raposa Serra do Sol indigenous territory (Supplementary Dataset 2). When overlaying a 10-km buffer onto the roads, a total of 321 PAs will be impacted, including a few in neighbouring countries, such as French Guiana, Venezuela, Peru and Bolivia (Fig. 4A and Supplementary Dataset 2). Roads crossing or adjacent to PAs and indigenous territories may undermine their intended protection15 and weaken or displace indigenous communities51.

Considering that most of the deforestation in the Amazon occurs adjacent to roads47, future developments will promote rapid and widespread forest loss3. Just the improvement of 2234 km of the trans-Amazonian highway may cause 561,000 ha of forest cover loss by 203015. Additionally, the construction or improvement of primary roads may facilitate the development of new illegal routes15, expanding deforestation frontiers3. Habitat loss and fragmentation in the Amazon will largely impact apex predator populations, which are particularly sensitive as they require large home ranges52. Future road developments in the rainforest may increase apex predator mortality, as seen in the Brazilian Atlantic forests, where fragmented jaguar populations suffer high road mortality from WVC46. Additionally, the opening of new roads will likely increase hunting pressure by making vast areas of forest accessible31. Moreover, demand for tiger substitutes in traditional Chinese Medicine is promoting poaching of jaguars, pumas and ocelots53. Thus, the expansion of roads will imperil the conservation of forest apex predators and their remaining wilderness habitat in the Amazon basin.

Africa

Road construction is occurring at an unprecedented rate in Africa. The African Union's Programme for Infrastructure Development proposed development corridors traversing the continent at a combined length of 56,000 km (Fig. 3B). The goal of this development is to push investment and unlock the potential of natural resources for national economies2. Roads, railways, powerlines, and pipelines are currently at various stages of planning and construction16.

Our assessment shows that the level of impact of these corridors on apex predators varies greatly across Africa (Fig. 4B). The impact from 19% of the corridors will be high (Impact level 5-7), primarily concentrated in large areas of East Africa (predominantly Tanzania, Kenya and Ethiopia), southern Africa (especially in Botswana, north-eastern South Africa, and southern Zimbabwe), as well as in road fragments in Cameroon and Senegal. Further, more than half of the development corridors (52.9%) distributed across the continent will have strong impacts on apex predators (Impact level 3-4; Fig. 4 B).

Development corridors will fragment the distributions of nine African apex predator species (Fig. 4E). Around 74% of the proposed corridors will be built within the range of the serval and spotted hyena ( Crocuta crocuta), and almost 59% in the range of the caracal ( Caracal caracal). These three predators have the largest distributions in Africa18. When assessing the impacts of future roads relative to species' distribution, the serval and spotted hyena are the most affected (Fig. 4E). Even though their risk to roads is currently moderate (Fig. 2), WVC are already affecting the species (Supplementary Fig. S1) and their exposure to roads is expected to increase in the future. Less than 10% of future roads will cross the known range of the brown hyena, but the development will cause a major impact on this species (Fig. 4E) due to its confined distribution in southern Africa18. The leopard will also be highly impacted by the development corridors relative to its distribution (Fig. 4E). Brown hyenas and leopards are already at high risk from roads (Fig. 2), making them particularly vulnerable to any new road development.

A total of 317 PAs will be bisected by 12.1% of the development corridors, and 1093 will be impacted within a 10-km buffer of the roads (Fig. 4A and Supplementary Dataset 2). Large wilderness landscapes and PAs will be affected. For example, the largest Ramsar wetland of international importance-Ngiri-Tumba-Maindome-will be impacted by 440 km of new roads. Located in the Congo basin, this wetland provides important forest habitat for the leopard54. Across East Africa, a significant number of PAs (80 in Tanzania and 49 in Kenya) will be bisected, including essential areas for the conservation of apex predators, such as the Serengeti and Katavi National Parks in Tanzania, and Tsavo National Parks in Kenya (Supplementary Dataset 2). Bisecting the Serengeti will cause devastating consequences impacting one of the world's greatest animal migrations and causing a domino effect on healthy apex predator populations55.

In East and southern Africa, roads will cause severe negative impacts in areas of extremely rich apex predator diversity (Fig. 1A). The vulnerable lion, cheetah, and leopard, and the endangered African wild dog occur in isolated subpopulations across the continent. Critically important sub-populations of these species occur in Tanzania, Kenya, Botswana, Namibia, and north-eastern South Africa18,56 and are expected to be heavily impacted by the proposed development corridors. Additionally, Southern Africa is a stronghold for the endemic brown hyena18﻿. Worryingly, development corridors in Senegal and Cameroon will cross some of the last remaining habitats of west African apex predators, where lion, leopard, and African wild dog occur in isolated populations mostly confined to fragmented PAs18.

The development corridors may lead to new human settlements and land use transformation16. Corridors crossing the Congo basin could increase logging3 thereby impacting the leopard population. With new roads, encroachment nearby PAs will likely increase and facilitate a rise in poaching35. Several apex predator species suffer from WVC across East and southern Africa (Fig. 1C), and this mortality is expected to increase with new road developments. This is particularly concerning for the serval which already incurs the third highest incidence of WVC in a single year (195 individuals; Supplementary Fig. S1). Overall, poorly planned roads will intensify the threats faced by healthy populations of apex predators across Africa.

Nepal

Nepal aims to expand its road network by completing the Postal highway. The construction of the 1792 km road traversing the southern lowlands has been delayed, with only 270 km completed so far57. Our analysis included only the east-west primary road of roughly 1000 km17 (Fig. 4 C) and not the adjoining roads that make up the entire Postal Highway project.

Our analysis indicates that the planned highway will cause severe impacts on apex predators in Nepal, mostly along the central and western Terai lowlands (Fig. 4C). Segments of the future highway crossing the central Chitwan-Parsa PA complex and the western Suklaphanta National Park show an alarming level of impact in PAs with high apex predator richness (Impact level 10). Across the west Terai, almost 20% of the road to be built will cause acute impacts on apex predator populations with impact levels ranging from 6 to 9. On the other hand, in the eastern Terai, the impact will be moderate as 20.9% of the proposed road length shows impact levels ranging from 1 to 2 (Fig. 4 C), due to the lower apex predator richness.

The Postal highway will cross the distribution area of seven apex predator species (Fig. 4F). There are, however, no recent records of the grey wolf in the Nepalese lowlands despite being considered part of the species' global distribution58. The new highway will be entirely built within the range of the dhole. Additionally, 77% and 45% of the total length will cross the distribution of the striped hyena and leopard respectively (Fig. 4F), species currently at high risk from roads (Fig. 2). Other impacted species include sloth bear, dhole and tiger, which are also found to be the three species most at risk from current roads (Fig. 2). Additionally, relative to their respective species distributions, these vulnerable apex predators will be severely affected by the planned road (Fig. 4 F).

If built as planned, 16.5% of the highway's length will intersect a proposed conservation area and four National Parks including their adjacent buffer zones. Adding a 10-km buffer, the highway is expected to impact eight PAs in Nepal and five transboundary PAs from India (Fig. 4C and Supplementary Dataset 2). In total, roughly 97 km of the highway will cross the Chitwan-Parsa complex. The Chitwan National Park is an important conservation area and a UNESCO World Heritage Site where six apex predators, expected to be affected by future roads (Fig. 4F), co-occur58. However, the supreme court of Nepal has ordered a halt to the construction of a new road in the Chitwan National Park until environmental impact assessments are approved by the National Park, UNESCO and other stakeholders59. The second most impacted PA is Suklaphanta National Park and its buffer zones -key areas for tiger conservation58- where almost 26 km of the highway is planned to be built (Supplementary Dataset 2).

These PAs and adjacent wildlife corridors are part of the Terai Arc Landscape (TAL), a conservation initiative established to bridge PAs and habitat corridors allowing the connectivity of large-mammal metapopulations60. The TAL extends along the south-western region of Nepal being a stronghold for both the sloth bear and tiger population in Nepal. Worryingly, it is expected to incur severe impacts from the proposed highway. The existing east-west Mahendra highway (running parallel to the proposed Postal highway) has already brought negative outcomes to the TAL through habitat fragmentation and quality reduction, obstruction of wildlife movements61 and increased incidence of WVC with tigers, leopards and striped hyenas (Supplementary Dataset 1). If not planned properly, the proposed Postal highway will degrade remaining habitats, jeopardise the connectivity of the TAL, and increase the threats faced by important apex predator populations.

Final remarks and conclusions

We reviewed how existing road networks produce substantial impacts on apex predators. We developed a method to assess the risk of predators from roads globally and showed that all species are currently exposed to the road network, most notably in Asia. Regionally, species are critically impacted by direct mortality but the impact of WVC is difficult to assess at the global scale due to the depauperate data in many countries and the underestimation of roadkills. Furthermore, the expected rapid rise of road development in developing countries will intensify the risk of apex predators and their habitats. We proposed a widely applicable method to estimate the potential impact of future road development on apex predators and applied it to three case studies. This method can be used to assess the potential impact of new roads at the country, regional or continental scale. We identified road segments in Nepal and Africa expected to cause the most severe impact crossing distributions of numerous apex predators. We also showed that proposed roads will impact forest predators over the entire Amazon basin (the largest road-free area of tropical rainforest) where deforestation and poaching are prone to increase with new developments. Roughly 500 PAs will be intersected by roads across our three case studies, threatening core habitats for apex predators. The impact of roads extends beyond predators to their habitats, potentially disrupting ecosystem functioning and stability8,9. By indicating species at risk from roads and future road segments with a high potential impact, our spatial analysis identifies key regions for the implementation of protective measures and the conservation of apex predators.

To reduce the environmental impact of infrastructure developments, the mitigation hierarchy defines a four-phase process: the first and most important step is avoidance, followed by minimization, rehabilitation, and biodiversity offsetting62,63. In accordance with the mitigation hierarchy, our analysis supports the calls made elsewhere: existing intact areas, such as pristine regions of the Amazon rainforest and African wilderness areas, should remain road-free. All proposed road developments should also expressly avoid PAs. New roads in these regions will prompt habitat clearing and overexploitation of wildlife1,3. Future roads should simultaneously avoid rich areas of co-occurring apex predators and areas with low richness where ecosystem function is dependent on one apex predator species. When road construction is unavoidable, the full suite of mitigation measures must be implemented with long-term monitoring to assess their effectiveness. The combination of crossing structures (over- and under-passes) and roadside fencing is the best known measure to minimize the impact on apex predators through reducing mortality and maintaining connectivity6. Particularly, when located in WVC hotspots and high-quality species habitat64. Finally, biodiversity offsetting should only be used as a last resort to complement the initial three phases of the mitigation hierarchy62,63, and not to justify road development.

It is vital that road planning committees include conservation scientists, the voices of all stakeholders -from local communities to government officials- and even wildlife protection organisations. Similarly, development financiers need to better integrate the mitigation hierarchy into their funding agreements, ensuring that the ultimate objective of no net biodiversity loss is maintained throughout62,63.

Our findings highlight the current risk of apex predators and future negative impacts from roads, assessed with methods that can be extrapolated to other species groups or areas of interest. We advocate the need to avoid the construction of environmentally harmful roads in wilderness areas, better road development planning and the installation of effective mitigation measures to protect apex predators, their habitats and ultimately ecosystem functioning.

Methods

Selection of apex predator species

Apex predators are defined here as terrestrial mammalian carnivores with an upper limit body mass (ULBM) of 18-34 kg or an average body mass (ABM) above 13 kg7. Species below this threshold that were previously found to occupy high trophic levels while exerting top-down regulation on ecosystem functioning were also included. A total of 36 species were considered (Supplementary Table S1) for which an IUCN range map is available18.

Wildlife Vehicle Collision data collection

To collate published Wildlife-Vehicle Collision records (Supplementary Fig. S1), systematic searches were conducted in Web of Science, SCOPUS, Crossref and Google scholar, in English, Spanish, Portuguese and French, using the following queries: (genus NEAR species) AND (road NEAR impact) OR (road NEAR kill) OR (wildlife NEAR vehicle NEAR collision); (atropellamientos OR colisión) AND (fauna OR animales) AND/OR carnívoros; atropelamentos AND (animais AND/OR silvestres) AND (carnivora OR predadores de grande porte); (collisions NEAR Faune AND/OR véhicules) AND/OR carnivore; respectively. Data from articles, congress proceedings, book chapters, databases, reports, news and thesis were included. We found 190 documents presenting WVC records, ranging from 1963 to October 2021. The number of killed individuals and study length ( i.e., years of study) were compiled; missing data values either for the number of individuals or years of study were assumed to be one. The rate of killed individuals per year was calculated as the fraction of total killed individuals over study length.

Underlying spatial data

Current global road density raster files at a spatial resolution of 5-arcminutes were downloaded from Globio11. Road types 1 to 4 ( i.e., highways, primary, secondary and tertiary roads) were aggregated to estimate the total road density in m/km ². Road type 5 ( i.e., local roads) were excluded due to spatial bias towards developed countries and mainly limited to large urban areas11. Georeferenced vector data for IUCN extant apex predator global distributions18 and PAs from the Word Database on Protected Areas (WDPA)48 were rasterized and assigned binary values for presence and absence using the same spatial resolution of road density data ( i.e., 5-arcmin, equivalent to ~ 8 km in the tropics). Apex predator species richness was calculated by overlaying all species distribution raster layers. All analyses and visual outputs were conducted and processed in R software65.

Species Risk to Roads

The risk to roads of each apex predator species i was calculated as the product of likelihood ( i.e., exposure to roads) and severity ( i.e., species vulnerability):

$$Road\,Risk_{i} = Road\,exposure_{i}^{*} \cdot Vulnerability_{i}^{*}$$

Road exposure is the square root of the density of roads within the range of a species i, which is calculated as the total length of roads inside the predator distribution (in m) divided by the area of its distribution (in km ﻿2 ﻿):

$$Road\,exposure_{i} = \sqrt {Road\,density}_{i}$$

Vulnerability for a species i is the aggregation of the proportion of range outside protected areas (\(nPA_{i}^{*}\)), the conservation status value (\(IUCN_{i}^{*}\)) categorized from Least Concern (LC = 1) to Critically Endangered (CR = 5), the number of threats as listed by the IUCN18 (\(TH_{i}^{*}\)) and the average body mass (\(BM_{i}^{*}\)) categorized as: very large predators (> 100 kg = 4), large predators (25-100 kg = 3), medium predators (15-25 kg = 2), small predators (8-15 kg = 1) (Supplementary Table S1). Body mass was interpreted as a proxy for home range size66, therefore bigger apex predators have an increased likelihood of encountering a road as a consequence of their large home ranges6, however, we clarify that this is a general rule as there are small-sized mammals with wide home ranges ( e.g., the wolverine). Weighting coefficients were assigned to variables based on their relative importance. We considered non-protected distribution area ( nPA) and IUCN category ( IUCN) most important for assessing species vulnerability due to the crucial role PAs play in carnivore species conservation67 and the importance of IUCN red list classification for assessing species conservation needs68. Number of threats ( TH) and body mass ( BM) were given half the weight because they do not strictly define how vulnerable a species is.

$$Vulnerability_{i} = nPA_{i}^{*} + IUCN_{i}^{*} + 0.5 \cdot TH_{i}^{*} + 0.5 \cdot BM_{i}^{*}$$

In Eqs. ( 1) and ( 3) the asterisk (*) denotes that the variable was previously normalised for scale uniformity by dividing by its maximum value.

Impact assessment of future road developments

To evaluate the potential impact of future roads on apex predators, the species risk to roads (as calculated in the previous section) and protected areas were spatially overlaid using raster data at 5-arcmin resolution, equivalent to ~ 8 km in the tropics. First, risk values were assigned to pixels corresponding to the distribution of the species, after which all species layers were overlaid to form the cumulative risk. Additionally, pixels corresponding to protected areas were given the average risk value of all species present in that pixel, according to the following formula:

$$Cumulative\,Road\,Risk_{px} = SSR_{px} + \beta \cdot PA_{px}$$

where for each pixel px, \(SSR_{px}\) = sum of the species risk value for all species present in the pixel, β = average value of species risk for the pixel, and \(PA_{px}\) = protected area expressed as binary values (0,1). Therefore, the value of each pixel corresponds to the sum of the risks of all species present in that pixel adding the average of the risks if protected (see Fig. 3).

The cumulative road risk of apex predators allows us to obtain the potential impact of future roads. To assess the impact of future developments we selected three case study areas of varying spatial scales based on their importance for apex predator species conservation and the availability of spatial data on proposed road developments. The Brazilian Amazon is currently the largest road-free area11 and an important stronghold for forest apex predator populations18. The continent of Africa supports a great diversity of apex predators and critically, road construction is occurring at an unprecedented pace and extent. Despite having a relatively small area, Nepal holds high richness and important populations of Asiatic apex predators58. Vector data for future road developments were collected for the three regions: Brazil69 masked by the amazon region70, African development corridors16 and the Postal highway in Nepal17. Road segments of future developments were assigned with the cumulative road risk values of the overlaying pixel. Finally, PAs that will be intersected by future road construction as well as affected by a 10-km buffer along each planned road were identified.

Data availability

The authors declare that the data supporting the findings of this study are available within the paper and its supplementary information files. All analyses were performed using publicly available datasets referenced in the Methods section of this manuscript.

Acknowledgements

We want to express our great appreciation and gratitude to Diego Juffe Bignoli, David Edwards and William F. Laurance who helped to review the manuscript and gave constructive advice to improve the paper. To Roshan Sharma who facilitated the Postal Highway shapefile and to Karis Daniel who helped with the writing style. The editor and referees made incisive comments which improved the paper. The project was financially supported by the European Commission through the program, Erasmus Mundus Master Course-International Master in Applied Ecology (EMMC-IMAE) (FPA 2023 - 0224/532524-1-FR- 2012-1-ERA MUNDUS-EMMC) - Coordination F-J Richard, Université de Poitiers.

Author information

Author notes

These authors contributed equally: Itxaso. Quintana, Edgar F. Cifuentes and Jeffrey A. Dunnink.

Affiliations

1. Département de Biologie des Organismes et des Populations, Université de Poitiers, Poitiers, France

Itxaso Quintana, Edgar F. Cifuentes, Jeffrey A. Dunnink, María Ariza, Daniela Martínez-Medina, Felipe M. Fantacini, Bibek R. Shrestha & Freddie-Jeanne Richard

2. Biodiversity and Development Institute, Unit 4, Gunner's Park, Epping 1, Cape Town, 7460, South Africa

Itxaso Quintana

3. Department of Plant Sciences, University of Cambridge Conservation Research Institute, The David Attenborough Building, Pembroke Street, Cambridge, CB2 3QZ, UK

Edgar F. Cifuentes

4. Laboratorio de Ecología de Bosques Tropicales Y Primatología (LEBTYP), Universidad de los Andes, Cra 1 Nº 18A - 12, Bogotá, Colombia

Edgar F. Cifuentes

5. Panthera, 8 West 40th Str., New York, NY, 10018, USA

Jeffrey A. Dunnink

6. Natural History Museum, University of Oslo, Blindern, P.O. Box 1172, 0318, Oslo, Norway

María Ariza

7. Fundación Reserva Natural la Palmita, Centro de Investigación, Grupo de Investigaciones Territoriales Para el Uso y Conservación de LA Biodiversidad, Bogotá, Colombia

Daniela Martínez-Medina

8. Instituto Ambiental Brüderthal, IAB, Brusque, SC, 88353-190, Brazil

Felipe M. Fantacini

9. Global Institute for Interdisciplinary Studies (GIIS), P.O. Box 3084, Kathmandu, Nepal

Bibek R. Shrestha

Contributions

All I.Q., E.F.C., J.D., M.A., D.M.M., F.M.F., B.R.S., F-J.R., conceived, designed, and wrote the manuscript. I.Q., E.F.C., J.D contributed equally to the paper. E.F.C. carried out spatial analysis and maps. I.Q. and E.F.C designed and created formulae and figures. M.A., D.M.M, F.M.F., B.R.S., I.Q., J.D., and F-J.R. collected articles and extracted data for wildlife-vehicle collision.

Corresponding authors

Correspondence to Itxaso Quintana, Edgar F. Cifuentes or Jeffrey A. Dunnink.

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Competing interests

The authors declare no competing interests.

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Quintana, I., Cifuentes, E.F., Dunnink, J.A. et al. Severe conservation risks of roads on apex predators. Sci Rep 12, 2902 (2022). https://doi.org/10.1038/s41598-022-05294-9
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DOI: https://doi.org/10.1038/s41598-022-05294-9

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Severe conservation risks of roads on apex predators - Scientific Reports

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The global expansion of road networks threatens apex predator conservation and ecosystem functioning. This occurs through wildlife-vehicle collisions, habitat loss and fragmentation, reduced genetic connectivity and increased poaching. We reviewed road impacts on 36 apex predator species and assessed their risk from current roads based on road exposure and species vulnerability.

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This article talks about wild dogs killing Madagascar wildlife and some of the dogs were reported to have killed fossa. Something needs to be done about this as soon as possible. Even if the the dogs only killed a small number like 1 or 2 you must be thinking about the resources they are taking away from the fossa. They are documented eating prey items that also are prey items of the fossa.

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How widespread is lemur and fossa meat consumption?

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A new study by WCS looks at the prevalence of human consumption of lemur and fossa (Madagascar's largest predator) in villages within and around Makira Natural Park, northeastern Madagascar, providing up-to-date estimates of the percentage of households who eat meat from these protected specie

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The Fabulous Fossa: Madagascar's Greatest Predator

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Mia-Lana Lührs is a PhD student of the department of Sociobiology/Anthropology at the University of Göttingen. Her thesis focuses on the social system of Madagascar's largest extant carnivore, the fossa (). Photo © Melanie Dammhahn.

(11/16/2010) A biological survey in Northeastern Madagascar has turned up evidence of extensive logging in Masoala National Park, a UNESCO World Heritage Site renowned for its biologically-rich rainforest. The findings suggest that harvesting of valuable hardwoods-including rosewood, ebony, and palissander-continues despite an official ban on the logging and export of timber.

(10/26/2010) Consumer demand for rosewood furniture and musical instruments is driving illegal logging in Madagascar's national parks, endangering wildlife and undermining local community livelihoods, according to a new report from the Environmental Investigation Agency (EIA) and Global Witness. The report, based on more than a year of investigations, shows that Madagascar's valuable hardwoods-including ebony, pallisander, and rosewood-are being illegally harvested from rainforest parks and trafficked to Asia, Europe, and the United States. The vast majority of timber however ends up in China, where it is converted into luxury furniture.

(02/18/2010) Of the known 634 primate species in the world 48 percent are currently threatened with extinction, making mankind's closes relatives one of the most endangered animal groups in the world. In order to bring awareness to the desperate state of primates, a new report by the International Union for the Conservation of Nature highlights twenty-five primates in the most need of rapid conservation action. Compiled by 85 experts the report, entitled , includes six primates from Africa, eleven from Asia, three from Central and South America, and five from the island of Madagascar.

(02/10/2010) In the aftermath of a military coup last March, Madagascar's rainforests have been pillaged for precious hardwoods, including rosewood and ebonies. Tens of thousands of hectares have been affected, including some of the island's most biologically-diverse national parks: Marojejy, Masoala, and Makira. Illegal logging has also spurred the rise of a commercial bushmeat trade. Hunters are now slaughtering rare and gentle lemurs for restaurants.

(08/11/2009) On March 17th of this year the President of Madagascar, Marc Ravalomanana, resigned his post. This made way for Andry Rajoelina, mayor of Madagascar's capital, to install himself as president with help from the military. The unrest and confusion that usually accompanies such a coup brought disaster on many of Madagascar's biological treasures. Within days of Ravalomanana's resignation, armed gangs, allegedly funded by Chinese traders, entered two of Madagascar's world-renowned national parks, Marojejy and Masoala parks, and began to log rosewood, ebonies, and other valuable hardwoods. The pillaging lasted months but the situation began to calm down over the summer. Now that the crisis in Madagascar has abated-at least for the time being-it's time to take stock. In order to do so, Mongabay spoke to Erik Patel, an expert on the Critically Endangered Silky Sifaka and frequent visitor to Madagascar, to find out what the damage looks like firsthand and to see what lessons might be learned.

(03/19/2009) Political turmoil in Madagascar has wrecked the country's emerging ecotourism industry and is now threatening to undo decades of conservation work. Conservation in Madagascar is highly dependent on income from tourism. Half of park entrance fees are returned to communities living in and around protected areas. Without this source of income, locals in some areas may turn to conservation areas for timber, fuelwood, agricultural land, and wildlife as food and for export.

(02/05/2007) It is called a rainforest for a reason-because it rains.... and rains. As my field partner, Angelin Razafimanantsoa, and I make our way down muddy mountainsides in the endless downpour, we stop only long enough to pick squirming, bloodthirsty leeches off each other's face. Hours pass as we wade through knee-deep streams rushing over smooth, slippery rocks and thick forest stands. Seven hours ago, we anticipated arriving at our next base camp in three hours' time. Now, as night is falling, it seems we have at least five hours more to go.

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Saving Madagascar's largest carnivorous mammal: the fossa

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The fossa. Photo © Nick Garbutt . An interview with Mia-Lana Lührs, a part of our Interviews with Young Scientists series. Madagascar is a land of wonders: dancing lemurs, thumbnail-sized chameleons, the long-fingered aye-aye, great baobab trees, and the mighty fossa. Wait-what? What's a fossa?

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Habitat loss and fragmentation have substantial impacts on the declining population. However, this is not their biggest threat. Local farmers are their biggest threat. They view fossas as dangerous predators that go after their poultry.

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Population

Population threats

Habitat loss is amongst the main reasons for the decline in the fossa population, fragmented populations becoming isolated in the forest patches that remain. However, the most important threat to their survival is probably local farmers, who see fossas as significant predators of poultry.

Population number

The fossa is widely distributed in Madagascar but it is very scarce and rare in most areas. According to the IUCN Red List, the total fossa population size is between 2,635 and 8,626 adults. Currently, this species is classified as Vulnerable (VU) and its numbers continue to decrease.

Ecological niche

A fossa is the top mammalian predator on Madagascar, impacting the numbers of many species of small birds, mammals, reptiles, and amphibians that they eat.

# data[].attributes.attachment_link.description
Habitat loss is amongst the main reasons for the decline in the fossa population, fragmented populations becoming isolated in the forest patches that remain. However, the most important threat to their survival is probably local farmers, who see fossas as significant predators of poultry.

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If you copy the link and paste it in a new tab you will be able to see the website page for the fossa by the IUNC red list. On here is also lists agriculture, aquaculture, biological resource use, natural system modification, and invasive species as things threating the population.

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Retaliatory killing are one of the fossa's biggest threats. Farmers who have lost their poultry and small livestock to this predator grow very annoyed and tired of dealing with the predators. In order to protect their animals or to get back at the fossa for killing their animals they kill them instead. Poultry are the most common farm animal that is killed by the fossa.

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Samuel D. Merson,

Luke J. Dollar,

Paul J. Johnson,

David W. Macdonald

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Abstract

Fosas ( Cryptoprocta ferox) are Madagascar's largest carnivores, occupying much of the island's forested landscape. This study provides the first evaluation of fosas' conflict with humans, a problem for many small and medium sized carnivores worldwide. We examined fosas' predation of poultry, and the subsequent retaliatory killing. Over 1750 households were interviewed across four regions, encompassing Madagascar's major forest types (deciduous/rainforest) and protected area classifications (national park, reserve and unprotected forest). Predation by fosa was the third highest reported cause (15%) of poultry mortality, with little evidence that coops were effective in reducing predation. Predation of poultry was more prevalent in deciduous forests, and most common during the evenings of the dry season. Over half of all interviewees said they disliked fosas, with loss of poultry the most commonly stated reason. Respondents' that had suffered poultry depredation and those with lower educational attainment were more likely to dislike fosas. Interviewees that disliked fosas and those that were wealthier were most likely to report having killed a fosa. A minimum of thirty fosas was killed in retaliation by our respondents during the year before the interviews. Given that the fosa population is in decline, and most of Madagascar's forests are likely to be too small to support sustainable populations, these killings may be detrimental to vulnerable sub-populations. These results shed insight into the cultural perceptions and predation patterns of a medium sized carnivore, with relevance to worldwide human-wildlife conflict of often overlooked smaller carnivores. We suggest that educational programs, guard dogs, poultry disease vaccinations and robust coop construction may be effective for improving attitudes and reducing retaliatory killing.

Citation: Merson SD, Dollar LJ, Johnson PJ, Macdonald DW (2019) Retaliatory killing and human perceptions of Madagascar's largest carnivore and livestock predator, the fosa ( Cryptoprocta ferox). PLoS ONE 14(3): e0213341. https://doi.org/10.1371/journal.pone.0213341

Editor: Ulrike Gertrud Munderloh, University of Minnesota, UNITED STATES

Received: February 27, 2018; Accepted: February 20, 2019; Published: March 15, 2019

Copyright: © 2019 Merson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: Data are available from The Oxford University Research Archive ( https://ora.ox.ac.uk/).

Funding: Megafaun provided funding for SDM to complete fieldwork and data collection in 2015 ( http://megafaun.org/). Duisburg Zoo provided funding for SDM to complete fieldwork and data collection in 2015 ( http://www.zoo-duisburg.de/artenschutz/fossa-fonds/). Wadham College Pollard fund provided funding for SDM to complete fieldwork in 2014 and 2015 ( http://www.wadham.ox.ac.uk/students/graduate-students/graduate-finance). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Introduction

Carnivore populations are in global decline, with human conflict and retaliatory killing a leading cause [ 1- 4]. While larger carnivores may be particularly at risk, owing to larger home ranges, low population densities, and low fecundity [ 4, 5], conflict with carnivore populations is not limited to larger species. Across the globe many small to medium carnivores are also persecuted, most often for their predation upon domestic poultry [ 6, 7].

Madagascar's carnivores, the Eupleridae, have been described as one of the most understudied and threatened group of carnivores worldwide [ 8]. The Eupleridae's largest carnivore, the fosa ( Cryptoprocta ferox) weighs on average 6-7 kg [ 9, 10] and are found across Madagascar's forested landscape. They are thought to be a keystone species due to their predation of lemurs and other species [ 11, 12]. Fosas occupy home ranges of up to 50 km ² [ 13] at population densities of 0.17-0.22 individual/km ² in rainforests and deciduous forests [ 14, 15]. It is this extensive ranging and predation on larger prey that leads them to encounter humans and their poultry. Knowledge of this relationship however, has hitherto been largely anecdotal.

Fosas are classified as a Category 1 Class 2 protected species under Madagascar's National Classification for Animal Species. Unlike a Category 1 Class 1 species that are strictly protected, fosas may however be hunted under authorisation, commercial, sport or regulatory conditions. These legislative discrepancies are however unlikely to be known my most Malagasy [ 16, 17].

Fosas have reportedly been killed for straying into villages where they may be perceived to be a threat to poultry [ 9, 18, 19] and other small livestock such as lambs [ 20]. Recent research in villages surrounding Ranomafana National Park [ 21] suggests fosas are not believed to affect many poultry keepers living at distance from the forest, with less than 1% of poultry predation attributed to fosas. However, individual attacks can be serious, with local farmers reporting incidents where fosas have killed all of their poultry once gaining access to their coop [ 18]. So called 'surplus killing', is likely to promote negative attitudes towards the predator, as has been observed of the red fox in the UK [ 22].

Negative attitudes to fosas are not only attributable to poultry predation, but also to taboos (known as fady). The most commonly cited is the belief that they consume the remains of villagers' ancestor's [ 19, 23]. Their resemblance to dogs is also a negative influence [ 20], perhaps underpinned by a general dislike of dogs, as recorded in Ranomafana National Park [ 24]. There are currently no published studies verifying these anecdotal accounts of human persecution of fosas. Given fosas' life history characteristics, potential persecution raises questions as to their long-term persistence in a landscape shared with humans.

This study examines fosas' impact across four regions, encompassing a representative sample of Madagascar's protected and unprotected areas. Our objectives were to: 1) Identify respondents' livestock ownership practices; 2) Examine the frequency and cost of fosa predation relative to other causes of poultry mortality; 3) Identify fosas' primary temporal and seasonal periods of poultry predation; 4) Estimate the annual numbers of fosas killed and examine variation among the four regions; 5) Identify the circumstances where predation of domestic poultry and therefore retaliatory killing of fosas is most likely, and 6) explore interviewee attitudes towards fosas. This information is fundamental for evaluating the retaliatory killing of fosas, and medium size predators in general, and understanding its socio-economic and cultural drivers.

Materials and methods

Study area

Surveys were conducted across four sites in Madagascar during April-July 2014, and May-August 2015. Sites were chosen to encompass a representative sample of two of the fosas' most extensive habitat types (deciduous and rainforest) ( Fig 1). Madagascar has a hierarchy of protected areas ranging from; Category I, Strict Natural Reserve, forbidding visitor entry; Category II, National Park, managed to allow public entry; and Category III, Special Reserve which are preserved purely for conservation, with a minimal tourist focus [ 25]. Our four sites incorporated two National Parks, one Special Reserve, one Private Reserve, and two unprotected areas ( Table 1).

Deciduous forest: National Park.

Located in the Boeny region, Ankarafantsika National Park (ANP)(16°14' S latitude, 46°55' E longitude) is Madagascar's largest (1350 km ²) tract of deciduous forest. ANP is surrounded by a population of over 37,000 human inhabitants in 133 villages and hamlets [ 26]. A road intersects the park's southwest and is flanked by six villages. These, and two villages to their southwest are the only villages inside the forest.

Deciduous forest: Special and private reserve, unprotected area.

The largest fragments of deciduous forest are in the central western region of Menabe. Three forests are situated along a south-north axis in Menabe's north. Andranomena Special Reserve (ASR)(20°17' S latitude, 44°50' E longitude) contains 64.20 km ² of deciduous forest with two large villages flanking its perimeter. North of Andranomena is the privately managed Kirindy reserve (20°04' S latitude, 44°66' E longitude), a former forestry concession and now a centre of research. Lastly Ambadira, unprotected and the most northerly forest, is bordered by one large village. During 2008-2010 it experienced annual deforestation rates as high as 13%, often a result of agricultural conversion [ 27].

Rainforest: National Park.

Covering over 155 km ², Andasibe-Mantadia National Park (AMNP)(18°23' S latitude, 48°28' E longitude) is located in the Moramanga region, and is one of the largest and most visited of Madagascar's protected areas. The commune of Andasibe lies at its centre, and is surrounded by several villages to the north, whilst southerly villages are located along the Route Nationale 2.

Rainforest: Unprotected area.

Situated in the Southeast region of Vatovavy-Fitovinany, the commune of Kianjavato (21°38' S latitude, 47°87' E longitude) is surrounded by several unprotected, and fragmented primary forests of Sangasanga, Tsiazonamboa, Ambatovaky, Tsitola and Vatovavy. These few remaining forests are characteristically low elevation humid evergreens surrounded by grassland, agricultural and secondary forests [ 28]. This forest primarily covers mountain ridges, with no fragment larger than 10 km ².

Sampling strategy and interview protocol

Malagasy field staff were trained to interview independently within each village. Before interviews, the research objectives were explained to the village president who gave permission for survey commencement. Interviewers fluent in Malagasy conducted surveys, and were assisted by a local villager fluent in the regional dialect and customs.

Villages were categorised as 'small' or 'large', roughly corresponding to villages less than or greater than 100 households. During surveys all households in small villages were visited. The head of each household was requested for interview and verbal consent acquired. If the individual was absent, a maximum of two further appointments were scheduled.

Within larger villages only a sample of households were interviewed. The area was divided into districts and sampled using the zig-zag transect method [ 29]. This method allows households not located on streets to be visited, ensuring the representative sampling of populous villages. Each interviewer was instructed to walk a zig-zag transect, sampling every second household. If the head of the household wasn't present, or was unwilling to be interviewed, the next household was surveyed. The potential bias introduced by unwilling respondents was probably negligible, as fewer than 2.5% declined to participate.

Questionnaire design

A pilot questionnaire was devised and trialled in ANP during 2013. The results of the pilot questionnaire were not used, however the feedback shaped its ultimate design.

The questionnaire was divided into four sections addressing respondents': i) demographic and socioeconomic information; ii) livestock ownership history; iii) dietary patterns; and iv) conservation perceptions and experiences (English and Malagasy questionnaires, S1 and S2 Tables). To promote trust, participants remained anonymous [ 30], however they were asked to reveal baseline demographic and socioeconomic information, such as employment, education level, ethnicity, household family structure, and livelihood indicators (asset ownership). Section two recorded participants' details of livestock ownership, specifically: i) breed and quantity; ii) use of protective measures (i.e. coops); iii) perceived causes of poultry mortality (previous year and lifetime); iv) and attitudes towards fosas. In ultimately interpreting attitude as a driver of behaviour, we considered the social-psychological theory of planned behaviour [ 31], which proposes that behaviour is influenced by attitude, subjective norms, and perceived behavioural control [ 32]. This was considered when interpreting models of interviewee attitude.

Participants were directly asked sensitive questions regarding any fosa-conflict encounters, including: the number of fosa killed; seasonal and temporal occurrence; reason for killing; and their use of the fosa carcass. As a result, the collected data is potentially affected by non-response [ 33] and social desirability biases [ 34, 35]. The impact of asking sensitive questions in areas of varying sensitivity (i.e. protected versus unprotected areas) was illustrated by Razafimanahaka et al. [ 36] who reported higher rates of bushmeat consumption using sensitive questioning techniques in protected versus unprotected areas. This potential underreporting was considered when interpreting regional retaliatory killing estimates.

Given the interviewee's potential reluctance to answer retaliatory killing questioning truthfully, interviewees were asked to report on other local villagers known to have killed a fosa. This questioning-method was included to produce a more accurate enumeration of fosas' killed. Despite the potential for misinformation when incorporating third-party estimates, claims were validated through the crosschecking of spatial-temporal information, with interviewers able to deduce the year and location of each attack.

Ethical clearance and research approval was granted by The University of Oxford's Central University Research Ethics Committee (Number: SSD/CUREC1A/14-010).

Data analysis

Data were analysed using the statistical package R [ 37]. Fisher Exact Tests and Chi-Squared tests of Independence were used in the analysis of seasonality, diel period, forest type, and interviewee coop usage's relationship with fosa poultry predation.

Three sets of generalised linear mixed effect models (GLMM) were used to examine the association of our explanatory variables with three response variables: i) fosas' predation of poultry; ii) interviewees' attitude towards fosas; and iii) retaliatory killing of fosas ( S3 Table).

'Last Year Predation' was measured as a binary 'yes/no' response to a question asking if the respondent had experienced fosa poultry depredation during the previous year. Eight a priori variables thought likely to affect a household's susceptibility to fosa predation, included; Forest Size, Village Size, River Barrier, Household Distance, Flock Size, Flock Coop, and Snare ( S3 Table). Any continuous variables were standardised.

Region was included as a fixed blocking factor accounting for geographic variation. This was included in all statistical models as an aspect of study design. Given the nesting of households within villages the identities of individual villages were included as levels of a random effect. Pearson's Chi-squared tests of Independence and Pearson Correlation Coefficients were used to identify collinearity among predictors. Forest type and Protection were not included as predictors in the GLMMs as they were highly confounded with Region.

A GLMM model with a binomial family and a logit link function (package lmer 1.1-12) was used to model the binary response variable, Last Year Predation. Akaike's information criterion (AIC) was used to rank models according to the most parsimonious set of predictors [ 38]. Model averaging was not used for the reasons given in [ 39], principally that with any non-trivial level of collinearity among predictors, inevitable with most observational studies, model averaged parameter estimates become unreliable. Instead, where no single model was clearly dominant, we scrutinised the pattern of parameter estimates in the models with the highest weights. Where a complex model was judged not to have a meaningful improvement in model fit, we preferred a simpler model nested within if where the delta AICc value was small (<2.0).

Attitude towards fosas, measured on a 5-point likert scale was used as an ordinal response variable and modelled with the fixed-effect predictors, Poverty, Education, Poultry Owned, Lifetime predation, Conservation Benefit, Conservation Experience, and Conservation Attitude (and Village identity as a random effect). A cumulative logit function was fit using the R package 'ordinal' (version 2015.6-28). Model selection was as previously described.

The final series of models exploring the potential predictors influencing the retaliatory killing of fosas followed model one's methods. The binary response variable (did interviewee's report having killed at least one fosa during their lifetime) was thought to be influenced by Poverty, Conservation Experience, Conservation Attitude, Conservation Benefit, and Fosa Attitude ( S3 Table). The household's relative poverty level was estimated using several of the indicators contained within the Multidimensional Poverty Index (MPI) [ 40]. Unfortunately given the structure of our questionnaire our estimate contained only indicators from the MPI's living standard dimension (excluding the health and education indicators). Our poverty estimate equally weighted six indicators to create a relative estimate of household poverty measuring poverty in an increasing scale from 0 to 1. Our indicators included assets ownership (i.e. mobile phone, bicycle), roof material, wall material, floor material, access to electricity and access to safe drinking water. Unfortunately, the poverty metric was unavailable for one of the regions (Boeny) due to changes in the content of the questionnaire between survey years. Consequently, two series of models were used for this response, with Poverty not included where all regions were used and with Poverty included (excluding observations from Boeny).

Results

In total, 1746 households were interviewed (1325 male interviewees, 410 female interviewees, mean age 42.4 ± 13.3 and 38.8 ± 13.9) over six months from April-June 2014, and May-August 2015 ( Table 1). 725 households were interviewed within and surrounding national parks, with 456 and 565 conducted within reserves and unprotected forests. Respondents were overwhelmingly farmers (77.5%). Most respondents' highest level of educational attainment (Malagasy equivalent in brackets) was either primary school (EPP) (43.6%), or junior secondary (CEG) (24.6%). A substantial minority reported having no education (22.5%). Senior secondary (Lyceé publics) or tertiary (Université) education was not commonly reported (8.7% and 0.7% respectively).

Livestock ownership and practices

Approximately 80% (n = 1391) of respondents owned livestock. Of these respondents, chickens (45.6%), zebu (25.1%) and ducks (15.6%) were most commonly owned. Of all the reared livestock, chickens were also bred in the greatest numbers, with a mean of 15.4 ± 15.63 (ranging from 1 to 150) owned per respondent.

87% of respondents who reared poultry used a protective structure. The majority, n = 595 (63%) stored their poultry in coops, inside their home (22%), or inside a cattle-pen (8.8%). 85% of poultry owners housed their poultry during the afternoon and evening, with the overwhelming majority doing so throughout the entire year (91%). Poultry were most commonly protected due to general security concerns and fear of predators (45.3% and 44.6% of respondents).

Poultry mortality

86.7% of poultry owners (n = 1136) reported experiencing poultry mortality (to causes other than for consumption) during the last year. Mortality resulting from disease (40.4%) was most commonly reported. Mortality to predation was most often attributed to birds (17.0%) with fosa depredation recorded by 276 respondents (15.3%).

Predation by fosas was significantly more prevalent in western deciduous forests than the eastern rainforests, where 85.6% of predation was reported (Chi-squared test of independence, X ² = 121.67, df = 1, p < 0.01) ( S4 Table).

Fosa depredation was significantly more likely to be reported as occurring during the evening in the dry season than any other season, and most commonly cited during the months of October to November (Chi-squared test of independence, X ² = 138.12, df = 4, p < 0.001) ( S1 Fig). There was no evidence that the use of a coop was associated with the frequency of poultry depredation ( S4 Table). In response to fosa depredation the majority of respondents reported: doing nothing (37.68%); improving their coop (36.52%); breeding dogs (8.12%); creating traps (4.35%); scaring the predator away (4.35%); or attacking the fosa (2.03%).

The most parsimonious model evaluating a household's susceptibility to previous year poultry depredation included Region and Snare use (as the only significant predictors (at p < 0.01 and p < 0.05)( S5 Table). Odds ratios indicated that households in Moramanga were 3.45 times and Vatovavy-Fitovinany were 7.14 times less likely to report predation ( Fig 2). The percentages reporting fosa predation were 22% in Boeny, 39% in Menabe, 11% in Moramanga and 7% in Vatovavy ( Table 1). Poultry keepers who used snares were 2.30 times more likely to have sustained poultry predation than those who did not ( Fig 2).

Attitudes

Over half (55.7%, n = 967) of respondents disliked fosas (responding either 'Strongly Dislike' or 'Dislike')( Fig 3). The most commonly stated reasons were fosas' depredation of poultry, their perception as their enemy and fosas' reputedly fierce nature. Conversely, of the 22.4% of respondents that liked fosas ('Like' or 'Strongly Like'), the principal reason was their status as a native species. Other respondents reported mixed-emotions because of their dislike of fosas' poultry depredation but appreciation for their role in consuming pests such as rats.

74.4% (n = 1203) of respondents believed fosas were of no personal benefit, mostly citing poultry depredation (44.8%)( S6 Table). In contrast, the remaining respondents (n = 414) saw fosas as beneficial for their role as a rat predator (23.9%), source of tourism revenue (21.2%) and ecosystem component (16.5%). When asked if respondents were fearful for their poultry, the majority of respondents who kept poultry (52.6%, n = 713) weren't concerned about fosas as a threat. The most popular reason stated was the presence of a geographical barrier (i.e. a river) surrounding their village (33%)( S6 Table). The majority (73%, n = 970) of respondents did not believe that fosa populations should be controlled, mostly because of their belief that fosas are one of god's creations (33.3%). The remaining interviewees believed that fosa overpopulation increased poultry depredation (44.6%).

The models examining interviewee attitude towards fosas revealed the strongest evidence for associations with Education, Lifetime Predation, and Region ( S7 Table). Interviewees who have experienced fosa predation during their lifetime were significantly more likely to have a negative attitude ( Fig 4). Likewise, interviewees' with lower levels of educational attainment were also more prone to exhibit negative attitudes ( Fig 4). Interviewees from Moramanga and Vatovavy-Fitovinany were more likely to hold a negative view of fosas compared with those from Menabe.

Retaliatory killing

Only 41 respondents (2.3%) claimed to have attempted to kill a fosa during their lifetime, with 32% (n = 13) of these purportedly successful. A total of nine fosas were directly killed by interviewees during the previous year (with nine more killed during their lifetime). The vast majority (85%) of these 18 mortalities occurred in deciduous forests (Chi-sq x ² = 8, df = 1, p < 0.05, testing for a significant difference in retaliatory killing in deciduous versus rainforests). 52.5% of respondents used snares, or batons and blowpipes (12.5% respectively) to attack fosas. 85% of interviewees who reported attacking fosas cited poultry depredation as their reason. Approximately half of respondents either ate or discarded the fosa, with the remaining interviewees selling or giving the carcass as a gift.

Eighty-five (4.86%) respondents knew of someone who had attacked a fosa during their lifetime, with 63.5% of these reported attacks successfully killing the fosa. Twenty-one fosas were purportedly killed in the previous year, with approximately 50 killed during the lifetime of the respondents.

Combining estimates of fosas killed directly by interviewees, and those reportedly killed by other local villagers, 30 fosas in total were killed during the previous year. A further 25 fosas were known to have been killed during the five preceding years, with 34 killed during the remainder of their lifetime ( Fig 5).

AMNP (Moramanga) had the highest number of fosas killed during the last year (13 individuals) and last five years (14 individuals)( Fig 5). ANP (Boeny) had the second highest number of individuals killed (8) during the previous year. Across the regions, 4% of households killed fosas in Boeny, 2% in Menabe, 4% in Moramanga, and 0% in Vatovavy-Fitovinany. No patterns were discernible between forests of different type or protection level.

The final set of models investigated a household's potential for retaliatory killing of fosas. The highest weighted model contained attitude and region, with interviewees' more likely to retaliate when holding a negative attitude. The analysis was repeated, this time including Poverty and excluding ANP households (where this variable was not available); this yielded similar results with Attitude and Region, and the Poverty predictor to be contained in the most parsimonious model ( S8 Table).

Scrutinising the final model (including Attitude, Region and Poverty) revealed that interviewees' from Vatovavy-Fitovinany were less likely to engage in retaliatory killing, whilst those that held negative attitudes towards fosas, and/or wealthier respondents were significantly more likely to engage in retaliatory killing ( S8 Table)( Fig 6). Odds ratios showed poorer interviewees' were 3.13 times less likely to kill a fosa (an increment of 1.0 on the 'Poverty' scale, i.e. the difference between the poorest and wealthiest individuals, had this effect on the response), and interviewees' who held favourable views towards fosas were 2.56 times less likely to have attempted killing them (an increment of one unit on this ordinal scale had on average this effect on the response, Fig 6).

Discussion

Fosa predation was reported by interviewees to be one of the greatest causes of poultry mortality. Its occurrence was concentrated in the western forests, and most often recorded during the dry season in the evening. There was no evidence that poultry coops were effective in reducing fosa predation, likely owing to their poor construction. Most interviewees' disliked fosas, with poultry predation the most commonly stated reason. Respondents who said they liked fosas commonly cited their endemicity, their impressiveness and their role as a rat predator. Interviewees that had suffered poultry depredation and those with less education were most likely to dislike fosas. Interviewees that disliked fosas and those that were wealthy were most likely to have killed a fosa. We estimated that a minimum of thirty fosas was killed in retaliation across our study regions during the year before interviews. Our results suggest that a strategy to reduce retaliatory killing should focus upon educating communities of fosas' ecological importance, whilst promoting the construction of sustainably built, robust poultry coops, in align with the use of guard dogs. Vaccination programmes should also be considered within this strategy to reduce the economic cost of the greatest cause of poultry mortality, disease, and to reduce the risk of greater disease transmission if poultry are housed within coops.

Poultry depredation

Recent estimates from Ranomafana suggested that < 1% of households' poultry mortality was attributable to fosas [ 21], supporting historical reports of anecdotally infrequent attacks [ 9, 18]. By contrast, approximately one in six interviewees' in our study reported fosa depredation. Together, these observations indicate that perceived predation by fosas is, while not rare, not the most economically damaging agent. Disease was reported to have killed nearly 40% of interviewees' poultry, with Newcastle disease the likely virus. Newcastle disease has been previously reported as the principal cause of rural poultry mortality in other areas of Madagascar [ 41], and it is undoubtedly the greatest cause of economic loss for rural poultry owners. Mortality from birds of prey was the second most common cause, although its impact is less economically detrimental due to their predation of chicks (costing around 400 Ariary at current prices). Conversely, fosas commonly consume adult chickens, typically valued at around 12,000 Ar (3,600 Ar = 1 USD). Fosas' tendency to kill all chickens when inside a coop, a predation behavioural characteristic repeatedly retold during interviews, and previously acknowledged in the literature, can result in a substantial cost to affected households (Albignac, 1973; Merson personal observ.). With some 70% of Malagasy households currently living below the poverty line (< 1 USD/day), the individual cost of fosas' predation upon respondents' livelihoods may be significant, despite being potentially half the economic cost of disease. In the absence of structurally robust coops effective at reducing wildlife predation, retaliatory killing of nuisance fosas is the likely response.

Fosas' predation of poultry was more frequent in deciduous forested regions. This may be attributable to higher fosa densities in deciduous forests [ 14, 15]. Anecdotal reports also support these estimates, with considerably higher trapping success in deciduous regions (Luke Dollar, Merson personal observ.). Higher fosa predation rates may also be due to lower prey availability in accord with greater aestivation of deciduous forest living species during the dry season.

Throughout both forest types, poultry depredation was significantly more likely to occur during the dry season (May to November). This pattern aligns with the aestivation and torpor of many of Madagascar's mammals [ 42- 44]. Hawkins and Racey's [ 12] dietary analysis found seasonal differences in the relative frequency (but not absolute number) of prey species in the fosas' diet. It might then be possible that higher winter poultry predation is a preferred strategy to combat reductions in species common during the summer months, such as tenrec [ 45]. Furthermore, most respondents claimed fosa poultry predation occurred most frequently between October and November. This is the end of the dry season, when fosas would have felt the brunt of winter and its associated reductions in prey, but also coincide with fosas' mating season. A recent study of fosa sociobiology in western Madagascar estimated male home ranges to have increased during the breeding season from c. 40 to c. 50 km ² [ 46]. These changes in male home range behaviour, including the likelihood of poorer body condition and increased metabolic demands, may create a propensity for greater overlap between fosas and human settlements.

Lastly, fosa predation of poultry was significantly more prevalent during the evening. Fosas' activity may be largely cathemeral, but it is also known to peak during the crepuscular hours [ 47, 48], with high activity during the evenings [ 49, 50]. Recent research revealed fosas may alter their activity pattern to avoid humans and dogs [ 48- 50], It may then be expected, similar to other instances of carnivore livestock predation [ 51], that fosas would choose to hunt poultry when human activity is presumably at its lowest during the evenings.

Households that used snares and those living in Menabe were significantly more likely to experience fosa predation. The positive association with snare use is potentially explained by the proximate reason that households using snares have experienced higher historic levels of fosa predation. Likewise, Menabe is a deciduous forest and contains Kirindy Reserve, one of the few forests in Madagascar with a highly habituated fosa population. Fosas in this sub-population may be less deterred by human presence, and more willing to venture into villages. In addition, this region continues to experience severe deforestation [ 27], with many of the remaining forests too small to sustain long-term fosa populations [ 14]. Given fosas' large home ranges, individuals in this region may be more inclined to leave the forest, promoting interaction with nearby villages.

Attitudes

The results of the GLMM estimated fosa poultry predation to be strongly linked to respondent attitudes, with interviewees who reported poultry losses to fosas significantly more likely to dislike them. This aligned with most interviewees' cited qualitative reason for disliking fosas (poultry predation). Despite seemingly pragmatic reasons for Malagasy dislike of fosas, underlying fady may also have shaped modern perceptions. Fosas' similarity to dogs was frequently mentioned, with dogs disliked both for cultural perceptions as being 'dirty', and for their occasional theft of food. Another common fady regularly cited was their dislike of fosas due to fosas' consumption of their ancestor's remains. Given some burial sites (for example tombs within mountainside caves) could be easily accessed by foraging fosas, the claim may have some validity and has been reported elsewhere [ 19, 23].

Other commonly cited anecdotes included stories of fosas having eaten missing people, packs of fosas attacking and consuming zebu, and attacks upon lone individual villagers-often resulting in death. The validity of these stories is unknown, however, given our understanding of fosas' behaviour, they are unlikely to be true. These stories do however reinforce a fundamentally negative perception of fosas. Our observation that attitudes were related to education suggests this affect could be reduced through educational programs.

Fosas were commonly liked as a predator of rats, a native species, and interestingly appreciated for their aesthetic appeal. Educational programs highlighting fosas' benefit as a rat predator were initiated by co-author L. Dollar in ANP wherein almost half of the total respondents that cited this reason were located.

Interviewees' who had experienced fosa predation, and those with lower education were more likely to negatively perceive fosas. Education is more likely to expose individuals to concepts of conservation, and its benefits. Consequently, fosas may be perceived not only as a pest, but also as an important component of Madagascar's ecosystem. Interestingly, interviewees' from Moramanga were most likely to negatively perceive fosas. This region encompassed AMNP, Madagascar's most visited national park. Despite its monetary benefits (employment, tourist revenue, park fees), many of the households interviewed were within the poorest villages. These villagers are still reliant upon traditional livelihoods, and are typically not benefitting from the park. It is also probably relevant that this region also recorded the greatest number of fosas killed, highlighting the association between attitude and retaliatory killing.

Retaliatory killing

In the previous year, nine fosas were reportedly killed by interviewees, increasing to thirty when including third-party accounts. This estimate should be interpreted as a minimum given the question's sensitivity, and the interviewee's probable reluctance to answer questions truthfully for fear of persecution by law enforcement or Madagascar National Park officials. Given fosas in Madagascar are largely known to be a protected species, interviewees are unlikely to reveal their killing when directly asked. The reluctance to answer honestly when directly questioned about illegal or socially unacceptable behaviours has been demonstrated for direct questioning of bushmeat hunting in Madagascar [ 36], and underreporting of retaliatory killing of fosas in our study is undoubtedly an issue.

Interpreting the impact of fosa mortalities is difficult, with island-wide population estimates likely inaccurate, and varying between 2,635-8,626 adults [ 52]. However, most of these sub-populations persist in extremely fragmented forests, thought to be too small to maintain long-term populations [ 14]. Hence, the fosa population is reportedly decreasing [ 53]. For some isolated populations, this human persecution can only accelerate their decline. It's therefore possible that these mortality rates are unsustainable, particularly within smaller forests.

In absolute numbers AMNP and ANP, the two largest forests and national parks, had the highest number of fosas killed during the previous year (including total recorded). Despite offering the highest legal protection, this did not demonstrably reduce retaliatory killing compared to forests of less protection. It could also be assumed that underreporting in these regions would be at its highest, as increased forest protection, NGO, and tourism presence, would likely result in greater sensitivity to report illegal or socially undesirable behaviours [ 36].

Respondents' with negative attitudes towards fosas were more likely to kill them if they had reported poultry predation. While this link is intuitively rational, the socio-psychological theory of planned behaviour suggest that attitudes alone, do not always predict behaviour, with cultural factors typically an important influence [ 54]. Carnivore killing results from an interplay between social and cultural factors, in addition to the individual-effective strategies for prevention need to take all of these into account [ 55]. Contrary to our expectation, wealthier households were most likely to have killed fosas. It was thought that poorer households with lower food security would be less tolerant of fosa predation and most likely to retaliate. We speculate that these households may have political or social power in association with greater wealth, and feel at greater liberty to kill fosas than poorer households with presumed less social/political power. Future research into community political and social structure may shed light on this.

When asked what interviewees' did with a killed fosas' remains, approximately half of respondents said they consumed it, further supporting the widespread consumption of fosa [ 50, 56- 58]. This trend likely reflects growing poverty and food insecurity across Madagascar.

Fosas were principally killed in retaliation for their consumption of poultry, likely underpinned by rational human's inclination to protect their livelihoods. However, it is also likely to be exacerbated by the unclear legislation defining fosa protection [ 16]. While nominally protected under national law the killing of nuisance species that damage an individual's property is permitted (Category 1, Class 2 Protected Species). Such conflicting legislation is counterproductive to efforts to protect fosas, and to establish an underlying protective culture towards Madagascar's wildlife.

Conclusions

Our results suggest that efforts to promote knowledge of the fosa could encourage tolerance, even in the presence of some impact on livelihood. Fosa predation was reported by a minority of poultry keepers, where it was likely not as economically important compared with the major source of mortality, disease. Educational material has potential to promote positive attitudes based on fosas' status as an iconic endemic species, tourist attraction and predator of other pests, including rats. Furthermore, the design and creation of robust poultry coops, in align with the use of guard dogs, an observed spatio-temporal deterrent of fosas [ 48- 50, 52, 58] could reduce retaliatory killing. Disease vaccination programmes should be considered with the implementation of robust coops and guard dogs to reduce its economic cost, and the risk of greater disease transmission amongst coop living chickens. Given the island-wide intrusion of humans into forested habitat, retaliatory killing reduction strategies must be trialled and deployed to ensure the persistence of one of Madagascar's most important species.

Acknowledgments

Thank you to our field team, the communities involved, and to those who supported our field endeavours, particularly, Pierrot Rahajanirina, MICET, and Fanamby. We would also like to thank the Madagascar Government, and Madagascar National Parks for research authorisation (Permit: 107/14-109/15/MEEMF/SG/DGF/DCB.SAPT/SCB).

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Retaliatory killing and human perceptions of Madagascar's largest carnivore and livestock predator, the fosa (Cryptoprocta ferox)

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Fosas (Cryptoprocta ferox) are Madagascar's largest carnivores, occupying much of the island's forested landscape. This study provides the first evaluation of fosas' conflict with humans, a problem for many small and medium sized carnivores worldwide. We examined fosas' predation of poultry, and the subsequent retaliatory killing.

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They consume all of the lemur species in Madagascar. Their preference seems to lean more toward the small to medium size prey but have been known to take down even the largest of the lemur species. They are generalist predators so they also hunt tenrecs, reptiles, birds, and insects. Fossas have also been known to capture and eat small pigs and poultry.

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The current population estimate is somewhere between 2,635 individuals to 8,626 individuals. The IUNC red list status is vulnerable as of 2015.

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The fossa is endemic to Madagascar and inhabits all of the forested lands found there. Today they are reduced to a tiny part of their native range. This is typically in protected parks and other protected areas. The reduction of suitable habitats is due to deforestation.

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When it comes to their social interaction fossas are solitary and territorial animals. They spend most of their days up in trees or resting and are most active in the morning and late afternoon.

They communicate mostly with sounds and scent, but when together there are also visual cues.

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The fossas have a polyandrous mating system. The females will choose a tree that is referred to as a mating tree and multiple males gather below and complete with one another to mate with her. Then the females give birth to about 2-4 cubs and raise them until they reach 15-20 months in age.

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Although the fossa is a solitary and territorial animal this study helped show that their home ranges overlap. Also there have recently been sighting reported in this study of fossa traveling together outside of their mating season. This raises question to just how solitary these species are.