Preliminary data on the distribution of free-ranging dogs in a Bulgarian National Park

Doykin, N., Popova, E., Zlatanov, V., Petrov, P., & Zlatanova, D. 2016. Preliminary data on the distribution of free-ranging dogs (Canis familiaris L.) in NP Vitosha, Bulgaria. Annuaire de l’Université de Sofia “St. Kliment Ohridski” Faculte de Biologie 2016, volume 101, livre 4, pp. 11-22. Youth Scientific Conference “Kliment’s Days”, Sofia 2015

Free-ranging dogs often leave the urbanized areas and stray into nearby mountainous habitats, even entering protected areas. This causes problems for the wildlife due to either direct predation or disturbance. Our camera trap survey (July 2013 - November 2014) in NP Vitosha, Bulgaria resulted in a total of 199 independent registrations of free-ranging dogs in 81 locations. In this preliminary study, we present the distribution, habitat selection, and distance from settlements and activity of free ranging dogs in Vitosha NP. The free-ranging dogs in Vitosha are predominantly diurnal, and show preference towards coniferous and mixed forests, mostly closed. Their distribution and activity patterns are influenced by human presence, which is due to the fact that they at least partially rely on human-sourced food. Some data for observations of wild animals influenced by dogs is also discussed. 

Dogs vs camera traps: a comparison of techniques for detecting feral cats

Glen, A. S., Anderson, D., Veltman, C. J., Garvey, P. M., & Nichols, M. (2016). Wildlife detector dogs and camera traps: a comparison of techniques for detecting feral cats. New Zealand Journal of Zoology, 1-11.

A major challenge in controlling overabundant wildlife is monitoring their populations, particularly as they decline to very low density. Camera traps and wildlife detector dogs are increasingly being used for this purpose. We compared the costeffectiveness of these two approaches for detecting feral cats (Felis catus) on two pastoral properties in Hawke’s Bay, North Island, New Zealand. One property was subject to intensive pest removal, while the other had no recent history of pest control. Camera traps and wildlife detector dogs detected cats at similar rates at both sites. The operating costs of each method were also comparable. We identify a number of advantages and disadvantages of each technique, and suggest priorities for further research.

Camera trap bias

Meek, P., Ballard, G., Fleming, P., & Falzon, G. (2016). Are we getting the full picture? Animal responses to camera traps and implications for predator studies. Ecology and Evolution.

Camera trapping is widely used in ecological studies. It is often considered nonintrusive simply because animals are not captured or handled. However, the emission of light and sound from camera traps can be intrusive. We evaluated the daytime and nighttime behavioral responses of four mammalian predators to camera traps in road-based, passive (no bait) surveys, in order to determine how this might affect ecological investigations. dogs, European red foxes, feral cats, and spotted-tailed quolls all exhibited behaviors indicating they noticed camera traps. Their recognition of camera traps was more likely when animals were approaching the device than if they were walking away from it. Some individuals of each species retreated from camera traps and some moved toward them, with negative behaviors slightly more common during the daytime. There was no consistent response to camera traps within species; both attraction and repulsion were observed. Camera trapping is clearly an intrusive sampling method for some individuals of some species. This may limit the utility of conclusions about animal behavior obtained from camera trapping. Similarly, it is possible that behavioral responses to camera traps could affect detection probabilities, introducing as yet unmeasured biases into camera trapping abundance surveys. These effects demand consideration when utilizing camera traps in ecological research and will ideally prompt further work to quantify associated biases in detection probabilities.
Wild

Use of camera traps to examine the mesopredator release hypothesis in a fragmented landscape

Cove, M. V., Jones, B. M., Bossert, A. J., Clever Jr, D. R., Dunwoody, R. K., White, B. C., & Jackson, V. L. (2012). Use of camera traps to examine the mesopredator release hypothesis in a fragmented Midwestern landscape. The American Midland Naturalist, 168(2), 456-465.

The mesopredator release hypothesis (MRH) has been suggested as a reason why many mammalian generalist mesopredators flourish and become abundant. However, the MRH has only been examined in a limited number of field studies. Some studies have argued that coyotes (Canis latrans) act as top predators in fragmented forest systems and coyote presence has a positive effect on song bird diversity and abundance by controlling mesopredator abundance. We integrated camera trap data and occupancy modeling to determine the factors that affect coyote detection probability and habitat use in a fragmented suburban landscape in central Missouri. We then examined the influence of coyote presence and other habitat variables on mesopredator detection probability and habitat use in the same system. Coyote detection was negatively related to increasing forest cover, whereas red fox (Vulpes vulpes) detection was positively related to increasing urbanization. Coyote occurrence models suggested little habitat selection, while the mesopredator occurrence models suggested an affinity for urbanization. Although there was a slight negative effect of coyote presence on site use by other mesopredators, we suggest that the smaller species are better adapted to coexisting with humans and thus have increased in abundance.

Detecting species interactions using remote cameras

Lazenby, B. T., Mooney, N. J., & Dickman, C. R. (2015). Detecting species interactions using remote cameras: effects on small mammals of predators, conspecifics, and climate. Ecosphere, 6(12), art266.

Effective conservation management requires an understanding of the source and direction of the many interactions that occur within ecological communities. Without this understanding, management interventions such as control or eradication of introduced species can have unexpected and undesirable outcomes. One of the challenges for wildlife managers is to garner relevant information for their site of management. In this paper we describe how images of mammals captured on remote cameras can be used to uncover behavioral interactions that can in turn help to identify and prioritize areas for more explicit research or management. Our cameras were set repeatedly at four sites over three years in Tasmania, Australia, and we used a series of generalized linear mixed models to interpret relative changes in count data of three species of small mammals: the introduced black rat Rattus rattus, and the native long-tailed mouse Pseudomys higginsi and swamp rat Rattus lutreolus velutinus. We also included two potential predators, the introduced feral cat Felis catus and the native Tasmanian devil Sarcophilus harrisii. We found that counts of the two species of native small mammals were correlated positively with each other, that swamp rats had a negative effect on black rats, and that black rats had a negative effect on the long-tailed mouse. Devils were important effects in most small mammal models. Despite their effect probably being underestimated by the remote camera survey method, feral cats were included in models for the long-tailed mouse. On the basis of the inclusion of native and both species of introduced mammals in long-tailed mouse models, we propose that the long-tailed mouse is a priority for further research. This research should clarify the competitive dominance and predatory pressure exerted by the black rat and feral cat, respectively, on this species, and also the potential for management of either introduced species to increase the impact of the other. We conclude that remote cameras can help to uncover cryptic or unsuspected interactions within ecological communities, and hence provide an informed basis for developing targeted research questions to increase the effectiveness of wildlife management.

Camera trapping of college's feral cats

Bainum, III,M., K.E. Sieving, R. McCleery, & D Wald.2015. Demonstrating camera trap techniques and their application for identifying feral cats across a college campus. University of Florida-Journal of Undergraduate Research, 16 (3)

Urban and suburban wildlife can be difficult to study through traditional wildlife techniques using direct, in situ human involvement. The use of remote sensing technology like trip cameras (or camera traps) can allow researchers to obtain high quality photographs of target species to be used to confirm the presence of species and even indentify individuals of a local population. A study at the University of Florida campus employed eight camera traps at four sampling locations to attempt to identify individuals of the feral cat (Felis catus) population as well as survey local mesopredator diversity. High-resolution photographs were used to select distinguishing characteristics of each cat in order to assign it an identification code and determine if individuals were moving among the sampling sites. Ten individuals were identified out of 118 total photographs with confirmed feral cat appearances. Only one individual appeared at more than one sampling site. The trip cameras captured photo evidence of four other species, all of which appeared at sites alongside cats suggesting some degree of resource competition may exist between these opportunistic predators. 

Stray cats and dogs exclude native predators in Madagascar

Farris, Z. J., Kelly, M. J., Karpanty, S., & Ratelolahy, F. (2015). Patterns of spatial co‐occurrence among native and exotic carnivores in north‐eastern Madagascar. Animal Conservation.

Human populations continue to increase and encroach on remaining natural habitats worldwide, resulting in greater numbers and larger ranges of commensal exotic carnivores such as cats and dogs. This results in increased interactions with native wildlife. In Madagascar, we know relatively little about the effects of domestic and/or feral dogs and cats on native carnivore populations. We investigated spatial interactions by combining photographic sampling across seven sites with two-species co-occurrence modeling to provide the first assessment of the spatial co-occurrence of native and exotic carnivores in Madagascar, including an examination of habitat characteristics that explain these relationships. Our surveys from 2008 to 2013 accumulated 2991 photo-captures of native and exotic carnivores in 8854 trap nights. We found that native and exotic carnivores in rainforest habitat occur together less often than expected and that exotic carnivores may be replacing native carnivores, particularly in forest areas nearest villages. Six of the native carnivores in this study had higher site use in the absence of exotic carnivores and their species interaction factors (SIF) revealed a lack of co-occurrence (e.g. SIF < 1.0). We found that nocturnal and/or crepuscular native carnivores were less likely to co-occur with exotic carnivores. We demonstrate the effectiveness of combining photographic sampling with co-occurrence modeling to investigate the effects of exotic carnivores on an entire community of native carnivores. Our study exposes the strong negative influence of exotic carnivores, ranging from exclusion to complete replacement of native carnivores, and we urgently recommend a combination of targeted educational programs and removal programs to combat the influx of exotic carnivores.

Dog among the most abundant mammals in a protected area in S Brazil

PAZIO, D.2014. Survey of terrestrial mammals of medium and large size in recovery areas of Parque Estadual do Lago Azul, Paraná, Brazil. 2013. 37p. Trabalho de Conclusão deCurso (Bacharelado em Engenharia Ambiental) -Coordenação de Engenharia Ambiental, Universidade Tecnológica Federal do Paraná, Câmpus Campo Mourão –PR.

The survey of mammals is important not only for understanding of distribution and autoecology of species, but also as a measure of environmental integrity and as a basis for management actions, especially when it’s occurs in protected areas. This study aimed to survey terrestrial mammal species of medium and large size in recovery areas of Parque Estadual do Lago Azul (PELA), Campo Mourão and Luiziana cities. We employed the following species survey techniques: cameras traps, footprints plots and opportunistic records. Samples were collected monthly during the period January to June 2013, and always occurred in three sampling points. We evaluated the level of vulnerability of species and the occurrence of invasive alien species from consulting of bibliography. We recorded 16 species in 13 families and 6 orders. Five species presented greater constancy of occurrence: three natives (Nasua nasua, Procyon cancrivorus, and Dasypus novemcinctus) and two invasives (Sus scrofa and Canis lupus familiaris). Seven species were considered with some degree of threat (Leopardus pardalis, Chironectes minimus, Cuniculus paca, Tapirus terrestris, Mazama americana, Mazama gouazoubira, and Dasyprocta sp.). The native species recorded in PELA indicate compatibility with regenerating areas. However, the constant record of invasive alien species becomes a concern, requiring that management measures are made.

PAZIO, D. 2014. Inventariamento de mamíferos terrestres de médio e grande porte em áreas de recuperação do Parque Estadual do Lago Azul,Paraná, Brasil. 2013. 37p. Trabalho de Conclusão de Curso (Bacharelado emEngenharia Ambiental) - Coordenação de Engenharia Ambiental, UniversidadeTecnológica Federal do Paraná, Câmpus Campo Mourão – PR.

O inventariamento de mamíferos é importante não apenas para o conhecimento da distribuição e autoecologia das espécies, mas também como medida de integridade ambiental e como subsídio para ações de manejo, principalmente, quando isso ocorre em unidades de conservação. Nesse sentido, este trabalho buscou levantar as espécies de mamíferos terrestres de médio e grande porte em áreas de recuperação do Parque Estadual do Lago Azul (PELA), municípios de Campo Mourão e Luiziana, unidade de conservação de proteção integral. Foram empregadas as seguintes técnicas de levantamento de espécies: armadilhas fotográficas, armadilhas de pegadas e registros oportunísticos. As coletas foram mensais, no período de janeiro a junho de 2013, e ocorreram sempre em três pontos amostrais. A partir do levantamento de espécies foi avaliado o nível de vulnerabilidade das espécies e a ocorrência de espécies exóticas invasoras, a partir do cruzamento com dados da bibliografia. Durante o período de amostragem foram registradas 16 espécies distribuídas em 13 famílias e 6 ordens. Das espécies registradas no PELA as que tiveram maior constância de ocorrência foram cinco, sendo três nativas (Nasua nasua, Procyon cancrivorus e Dasypus novemcinctus) e duas exóticas invasoras (Sus scrofa e o Canis lupus familiaris). Já as espécies consideradas com algum grau de ameaça foram sete (Leopardus pardalis, Chironectes minimus, Cuniculus paca, Tapirus terrestris, Mazama americana, Mazama gouazoubira e Dasyprocta sp). As espécies nativas registradas no PELA indicaram um bom grau de compatibilidade com uma floresta em regeneração. No entanto, o constante registro de espécies exóticas invasoras torna-se uma preocupação, necessitando que medidas de manejo sejam efetuadas.

Human infrastructures and feral pets explain the distribution of native carnivores

Zapata G, Branch L, 2014. Evaluación de los factores determinantes de presencia – ausencia de los carnívoros en los Andes ecuatorianos. En: Cuesta F, Sevink J, Llambí LD, De Bièvre B, Posner J, Editores. Avances en investigación para la conservación de los páramos andinos, CONDESAN.

Carnivore surveys using scent stations, camera traps and reconnaissance surveys were carried out in five study areas in the northern Ecuadorian Andes. Nine species of carnivores are known to occur in the Ecuadorian Andes (puma, pampas cat, Andean fox, long-tailed weasel, Colombian weasel, striped hog-nosed skunk, mountain coati, neotropical river otter, and Andean bear).
A total of six species were recorded. The pampas cat, the Colombian weasel, and the Neotropical river otter were the three species that were not recorded. Data analysis suggests that the “distance to the nearest
house”, the “distance to roads”, and the “presence of exotic carnivore species” (feral cats and dogs) are the
most important variables that explain the presence of native carnivore species in the paramo ecosystem of northern Ecuador.

Scavenging by Wild Dogs, Red Foxes and Feral Cats in South-Eastern Australia

Forsyth, D. M., Woodford, L., Moloney, P. D., Hampton, J. O., Woolnough, A. P., & Tucker, M. (2014). How Does a Carnivore Guild Utilise a Substantial but Unpredictable Anthropogenic Food Source? Scavenging on Hunter-Shot Ungulate Carcasses by Wild Dogs/Dingoes, Red Foxes and Feral Cats in South-Eastern Australia Revealed by Camera Traps. PloS one, 9(6), e97937.

There is much interest in understanding how anthropogenic food resources subsidise carnivore populations. Carcasses of hunter-shot ungulates are a potentially substantial food source for mammalian carnivores. The sambar deer (Rusa unicolor) is a large (≥150 kg) exotic ungulate that can be hunted throughout the year in south-eastern Australia, and hunters are not required to remove or bury carcasses. We investigated how wild dogs/dingoes and their hybrids (Canis lupus familiaris/dingo), red foxes (Vulpes vulpes) and feral cats (Felis catus) utilised sambar deer carcasses during the peak hunting seasons (i.e. winter and spring). We placed carcasses at 1-km intervals along each of six transects that extended 4-km into forest from farm boundaries. Visits to carcasses were monitored using camera traps, and the rate of change in edible biomass estimated at ~14-day intervals. Wild dogs and foxes fed on 70% and 60% of 30 carcasses, respectively, but feral cats seldom (10%) fed on carcasses. Spatial and temporal patterns of visits to carcasses were consistent with the hypothesis that foxes avoid wild dogs. Wild dog activity peaked at carcasses 2 and 3 km from farms, a likely legacy of wild dog control, whereas fox activity peaked at carcasses 0 and 4 km from farms. Wild dog activity peaked at dawn and dusk, whereas nearly all fox activity occurred after dusk and before dawn. Neither wild dogs nor foxes remained at carcasses for long periods and the amount of feeding activity by either species was a less important predictor of the loss of edible biomass than season. Reasons for the low impacts of wild dogs and foxes on sambar deer carcass biomass include the spatially and temporally unpredictable distribution of carcasses in the landscape, the rapid rate of edible biomass decomposition in warm periods, low wild dog densities and the availability of alternative food resources.

Incursion of domestic carnivores around urban areas: Three camera-trapping studies

Marks, B. K., & Duncan, R. S. (2009). Use of forest edges by free-ranging cats and dogs in an urban forest fragment. Southeastern Naturalist, 8(3), 427-436.

Free-ranging Felis catus (Domestic Cat) and Canis familiaris (Domestic Dog) can greatly impact native prey populations, but little is known about their occurrence in urban forest fragments. In this study, we used camera traps to photograph (capture) cats, dogs, and native wildlife in a 409-ha urban forest in Birmingham, AL from Jan–Apr 2007. Habitat treatments included forest interior and forest edges by industrial lands, neighborhoods with higher house values, and neighborhoods with lower house values. We employed both conservative (n = 31) and liberal (n = 64) methods of tallying the number of individual dogs, cats, and native mammals captured. Dogs and cats combined comprised 19% (conservative) and 26% (liberal) of all photographic captures. Procyon lotor (Raccoon) were the most abundant of the 7 native species at 32% (conservative) and 53% (liberal) of all captures. Dogs were more abundant in neighborhood edges, and cats were more abundant in the forest interior. Cats and dogs combined were 75% (conservative) and 86% (liberal) of captures from the forest interior. Captures of native species were far more frequent in neighborhood edges (conservative = 86.9%, and liberal = 92.3%) than in other treatments. These findings demonstrate that exotic predators can be an important ecological presence in certain portions of urban forest fragments, and more extensive studies of their impact are needed.

Ordeñana, M.A, K. R. Crooks, E.E. Boydston, R.N. Fisher, L.M. Lyren, S. Siudyla, C.D. Haas, S. Harris, S.A. Hathaway, G.M. Turschak, A. K. Miles, & D.H. Van Vuren (2010) Effects of urbanization on carnivore species distribution and richness. Journal of Mammalogy, 91 (6): 1322-1331.

Urban development can have multiple effects on mammalian carnivore communities. We conducted a meta-analysis of 7,929 photographs from 217 localities in 11 camera-trap studies across coastal southern California to describe habitat use and determine the effects of urban proximity (distance to urban edge) and intensity (percentage of area urbanized) on carnivore occurrence and species richness in natural habitats close to the urban boundary. Coyotes (Canis latrans) and bobcats (Lynx rufus) were distributed widely across the region. Domestic dogs (Canis lupus familiaris), striped skunks (Mephitis mephitis), raccoons (Procyon lotor), gray foxes (Urocyon cinereoargenteus), mountain lions (Puma concolor), and Virginia opossums (Didelphis virginiana) were detected less frequently, and long-tailed weasels (Mustela frenata), American badgers (Taxidea taxus), western spotted skunks (Spilogale gracilis), and domestic cats (Felis catus) were detected rarely. Habitat use generally reflected availability for most species. Coyote and raccoon occurrence increased with both proximity to and intensity of urbanization, whereas bobcat, gray fox, and mountain lion occurrence decreased with urban proximity and intensity. Domestic dogs and Virginia opossums exhibited positive and weak negative relationships, respectively, with urban intensity but were unaffected by urban proximity. Striped skunk occurrence increased with urban proximity but decreased with urban intensity. Native species richness was negatively associated with urban intensity but not urban proximity, probably because of the stronger negative response of individual species to urban intensity.

Fandos, G., Fernández-López, J., & Tellería, J. L. (2012). Incursion of domestic carnivores around urban areas: a test in central Spain. Mammalia, 76(2), 223-225.

Although domestic carnivores are frequently considered a threat to wildlife inside and around urban areas, little is known about the incursions of these animals from urban areas to the surrounding habitats. To explore this, we sampled carnivores in wooded areas surrounding four villages located in the mountains north of Madrid by using 40 camera-trapping stations. They were distributed at regular distances within a perpendicular transect distributed from 10 to 2000 m from the urban border. The results suggest that the incidence of domestic carnivores (cats and dogs) was constrained to <400 m from the urban border, and that the presence of domestic carnivores did not interfere with the distribution of wild carnivores (foxes, beech martens, badgers, genets, etc.), which show random distribution patterns around villages. This means that overpredation at the village edges could mainly be due to the effect of domestic animals and not to that of wild carnivores attracted to urban areas

Presence of domestic dogs in Atlantic forest in Brazil

Srbek-Araujo, A. C., & Chiarello, A. G. (2008). Domestic dogs in Atlantic forest preserves of south-eastern Brazil: a camera-trapping study on patterns of entrance and site occupancy rates. Brazilian Journal of Biology, 68(4), 771-779.

Presence of exotic species in forest remnants is a major concern for the conservation of wild species, not only on islands, where potential impact is higher. Although the problem is widespread and increasing, there are few studies on Neotropical forests. Here we quantify the occurrence of domestic dogs (Canis lupus familiaris) in an Atlantic forest reserve in south-eastern Brazil (Santa Lúcia Biological Station - SLBS). Throughout two years of monitoring with camera traps (2,142 camera-days), 25 records of 16 individual dogs were obtained in the interior of SLBS, making dogs the fourth most frequently recorded species of mammals in general and the first-ranking among Carnivora, ahead of the ocelot and puma, the top two terrestrial predators present in SLBS. Dogs entered the forest year round, in almost half of the sampled months (48%), and predominantly during daytime (89%). They were detected in various trails inside the reserve, but mostly in areas nearest to the reserve's border (<200 m from the edge). Record rates of domestic dogs did not correlate significantly with climate variables, with frequency of mammal records and richness in general, or with any particular mammal species (Spearman rank correlation, p > 0.05 in all cases), suggesting an erratic, non-seasonal pattern of entrance in the reserve. Data indicate that domestic dogs can be abundant and frequent visitors to little disturbed Atlantic forest reserves even when these are located in regions of low density of human population. The potential impact to native fauna is discussed.

Dog, the most recorded carnivore in Brazilian Atlantic forest

Paschoal, A. M. O., Massara, R. L., Santos, J. L., & Chiarello, A. G. (2012). Is the domestic dog becoming an abundant species in the Atlantic forest? A study case in southeastern Brazil. Mammalia, 76(1), 67-76.

The Brazilian Atlantic forest has been reduced to a small fraction of its original area, with most remaining fragments being small and surrounded by anthropogenic matrices. This degree of disturbance, together with the increasing sprawl of cities towards the rural zone, greatly facilitates the entrance of domestic animals into these remnants. We used camera traps to compare the abundances of the domestic dog with a similarly sized native carnivore, the ocelot, in a 957-ha reserve of the Brazilian Atlantic forest in a landscape largely composed by pastures and agriculture. The dog was the most recorded species among all 17 mammal species “captured” by the cameras. Dog abundance (32–38 dogs) and density (0.812–1.813 dogs/km²) were significantly higher than that of the ocelot (n=2 ocelots; density=0.158–0.347 ocelots/km²). Although our result is restricted to a single study site, it is supported by an increasing number of recent studies, which have detected dogs inside other Atlantic forest reserves. Our study suggests, therefore, that this invasion might be more widespread than generally thought. The presence of the domestic dog is a threat to native fauna and constitutes an important edge effect of human presence at the rural zone.

Cat detection depending on dominant native predator presence

Lazenby BT, & Dickman CR (2013) Patterns of Detection and Capture Are Associated with Cohabiting Predators and Prey. PLoS ONE 8(4): e59846. 

Avoidance behaviour can play an important role in structuring ecosystems but can be difficult to uncover and quantify. Remote cameras have great but as yet unrealized potential to uncover patterns arising from predatory, competitive or other interactions that structure animal communities by detecting species that are active at the same sites and recording their behaviours and times of activity. Here, we use multi-season, two-species occupancy models to test for evidence of interactions between introduced (feral cat Felis catus) and native predator (Tasmanian devil Sarcophilus harrisii) and predator and small mammal (swamp rat Rattus lutreolus velutinus) combinations at baited camera sites in the cool temperate forests of southern Tasmania. In addition, we investigate the capture rates of swamp rats in traps scented with feral cat and devil faecal odours. We observed that one species could reduce the probability of detecting another at a camera site. In particular, feral cats were detected less frequently at camera sites occupied by devils, whereas patterns of swamp rat detection associated with devils or feral cats varied with study site. Captures of swamp rats were not associated with odours on traps, although fewer captures tended to occur in traps scented with the faecal odour of feral cats. The observation that a native carnivorous marsupial, the Tasmanian devil, can suppress the detectability of an introduced eutherian predator, the feral cat, is consistent with a dominant predator – mesopredator relationship. Such a relationship has important implications for the interaction between feral cats and the lower trophic guilds that form their prey, especially if cat activity increases in places where devil populations are declining. More generally, population estimates derived from devices such as remote cameras need to acknowledge the potential for one species to change the detectability of another, and incorporate this in assessments of numbers and survival.

Estimating feral cats density on Corvo island (Azores)

Oppel, S., , Hervias, S., Oliveira, N., Pipa, T., Cowen, H., Silva, C., Geraldes, P., 2012 Estimating feral cat density on Corvo island, Azores, to assess the feasability of feral cat eradication. Airo, 22: 3-11.

Feral cats have had negative effects on native biodiversity on many islands worldwide. Eradicating feral cats from islands is often feasible, and can yield great benefits to native biodiversity, especially for seabirds. Corvo Island (Azores) is an important island where feral cats limit the distribution and abundance of breeding seabirds. To assess whether the eradication of feral cats on Corvo would be feasible we used camera traps to estimate the density of feral cats. We deployed 24 camera traps at 253 locations around the island for 14 months, and identified cats detected by camera traps individually based on the coat colour. We then used spatially explicit capturere-capture models to estimate cat density for Corvo. Cat density in the uninhabited upland part of Corvo, which is dominated by cow pastures, was 0.036 (95% CI 0.025–0.054) cats/ha. The lowland part of Corvo, which is inhabited by humans and contains domestic cats, had an estimated cat density of 0.734 (0.581 – 0.927) cats/ha. Overall, we estimated that the cat population on Corvo during our study period included 163 (123 - 228) individuals. The estimated cat densities are within the range of cat densities from other islands where cats have been successfully eradicated, and we conclude that feral cat eradication on Corvo would be technically feasible. However, the co-existence of feral and domestic cats would create operational challenges, and the current lack of a legal framework to ensure that all domestic cats are sterilised would increase the risk of a feral cat population becoming re-established after eradication.

Dogs, one of the biggest threats to pudu

Silva-Rodríguez, E. A., Verdugo, C., Aleuy, O. A., Sanderson, J. G., Ortega-Solís, G. R., Osorio-Zúñiga, F., & González-Acuña, D. (2010). Evaluating mortality sources for the Vulnerable pudu Pudu puda in Chile: implications for the conservation of a threatened deer. Oryx, 44(01), 97-103.

We assessed the importance of potential sources of mortality for the Vulnerable southern pudu Pudu puda in southern Chile using the clinical records of wildlife rehabilitation centres, necropsies of animals found in the field and a review of the diet of potential predators. To assess whether the identified mortality sources operate in nominally protected areas, we conducted a camera-trap survey in two areas to determine the presence of pudus and their potential predators. Predation by domestic dogs Canis lupus familiaris and car collisions were the commonest causes of pudu admissions to rehabilitation centres (35 of 44) and of deaths of animals encountered opportunistically in the field (seven of 14). Field data suggest that poaching could also be an important threat to pudus. Pudus were detected in both areas surveyed, accounting for 15.6% of mammal detections. Dogs accounted for 47.8% of all detections of potential predator species, followed by pumas Puma concolor (17.4%), guignas Leopardus guigna (17.4%) and chilla foxes Lycalopex griseus (17.4%). The literature survey implicated only pumas as important pudu predators among native carnivores. Our data suggest that, aside from forest loss, dogs, road kills and probably poaching are important concerns for pudu conservation. Our frequent detections of free-ranging dogs associated with roads within nominally protected areas suggest that long-term efforts to conserve pudu will require not only the protection of remnant native forest but also substantive environmental education to modify dog management near protected areas.

Dogs affecting distribution of threatened ungulates

Silva-Rodriguez, E.A. & K.E. Sieving. 2012. Domestic dogs shape the landscape-scale distribution of a threatened forest ungulate. Biological Conservation, 150: 103-110

Domestic dogs are the most abundant carnivores worldwide, primarily due to human support. Food and other subsidies to dogs do not necessarily prevent dog predation on wildlife, particularly where dogs are allowed to range freely. Dog impacts on wildlife are suspected to be significant, yet the nature of dog– wildlife interactions is not fully understood. We tested the hypothesis that the distribution of dogs can significantly influence the space use of potential prey, and that both lethal and non-lethal mechanisms may underlie this interaction. If this is true, then we predicted that (1) evidence of predation and harassment by dogs should be evident where prey and dog activities overlap and (2) potential prey should be less frequent in areas where the probability of dog presence is high. To test these predictions we conducted two related studies. (1) We interviewed dog owners to estimate the probability of dog attack on pudu (Pudu puda), a globally vulnerable deer, and the lethality of these attacks. (2) We conducted a camera-trap survey documenting the landscape-scale distribution of pudu and dogs. Interviews showed that both the probability of dog attack on pudu (>85%) and the lethality of such attacks was high (50%). In occupancy models applied to the camera-trap data, the variable that best explained the distribution of pudus was the probability of dog presence. We tested three alternative explanations for the negative association between pudus and dogs that were not supported. Our findings suggest that dogs are efficient at chasing pudu they detect and that both predation and non-lethal (avoidance) consequences of harassment may be shaping the distribution of pudu. This work brings into focus important mechanisms underlying the threats of domestic dogs to endangered prey.