Raining feral cats and dogs? Implications for the conservation of medium-sized wild mammals in an urban protected area

Lack of accessibility and clarity in regulations concerning dog access to protected areas lowers public awareness

While natural protected areas are conceived for nature conservation, humans and their activities must also be considered. Conflict between the public and managers of protected areas can be minimized by regulations that clearly communicate which activities are allowed. Domestic dogs (Canis lupus familiaris) affect threatened species and impact numerous protected areas. In this study we evaluate: (1) the accessibility and clarity of regulations regarding dog access to protected areas in Argentina, (2) the public's knowledge of these regulations, (3) the public's expectations of the regulations (4) which institutions people consider should act when dog aggression occurs, and (5) measures suggested by people when dog aggression occurs. Poor accessibility and clarity of regulations were associated with poor public knowledge of them; there was also an association between visited protected areas that did not mention regulations and respondents who reported not knowing whether dogs were allowed or thinking dogs were allowed. In general, the respondents supported measures to regulate dog access to protected areas and the control of problematic dogs. We discuss several aspects that lead to a lack of clarity on dog regulations in protected areas and suggest approaches that could be used to overcome this conservation problem.

Seasonal Movement Patterns of Urban Domestic Cats Living on the Edge in an African City

Domestic cats (Felis catus) are amongst the most destructive invasive vertebrates globally, depredating billions of native animals annually. The size and seasonal variation of their geographical “footprint” is key to understanding their effects on wildlife, particularly if they live near conservation areas. Here we report the first GPS-tracking studies of free-roaming owned cats in the city of Cape Town, South Africa. A total of 23 cats was tracked (14 cats in summer, 9 in winter) using miniature (22 g) GPS locators in 2010–2011. In summer, all cats living on the urban-edge (UE: n = 7) made extensive use of protected areas, while only one of seven urban (U) cats (>150 m from the edge) did so. In winter two of four UE and two of five U cats entered protected areas. Home ranges (95% kernel density estimates) were significantly larger in summer (3.00 ± 1.23 ha) than winter (0.87 ± 0.25 ha) and cats ventured further from their homes in summer (maximum 849 m) than in winter (max 298 m). The predation risk posed by caracal (Caracal caracal) may limit the time cats spend in protected areas, but our results suggest that cat buffers around conservation areas should be at least ~600 m wide to reduce impacts to native fauna.

Effect of urbanization on the opossum Didelphis virginiana health and implications for zoonotic diseases

Urban animals can be an important threat to human health as possible hosts of zoonotic diseases and their susceptibility to these diseases can depend on their overall health conditions. Thus, it is important to understand the factors that determine their health conditions. For this, we studied Virginia opossums (Didelphis virginiana) in six locations with different urbanization levels and types in Mexico City, Mexico. We trapped opossums and measured eight health-related characteristics (number of ectoparasites and tartar severity, among others) and estimated the percentage of area covered by the four main types of terrain (natural vegetation, managed vegetation, impermeable terrain and constructions). Data were analyzed by a canonical correspondence analysis. We found that impermeable terrain was related to negative health characteristics, while the constructions were opposite to impermeable terrain and mostly related to good health characteristics. At the same, time constructed areas held a smaller population than the natural areas. This suggests that constructed areas provide few shelters, but opossums are healthier there, while impermeable areas provide more shelter but cause more health problems to the animals, thus increasing the chances of zoonotic diseases. We recommend reducing the impermeable areas in city planning to contribute to a better health of the urban animals and therefore reduce risks of zoonotic diseases with potentially disastrous results.

Predation and Scavenging in the City: A Review of Spatio-Temporal Trends in Research

Many researchers highlight the role of urban ecology in a rapidly urbanizing world. Despite the ecological and conservation implications relating to carnivores in cities, our general understanding of their potential role in urban food webs lacks synthesis. In this paper, we reviewed the scientific literature on urban carnivores with the aim of identifying major biases in this topic of research. In particular, we explored the number of articles dealing with predation and scavenging, and assessed the geographical distribution, biomes and habitats represented in the scientific literature, together with the richness of species reported and their traits. Our results confirmed that scavenging is largely overlooked compared to predation in urban carnivore research. Moreover, research was biased towards cities located in temperate biomes, while tropical regions were less well-represented, a pattern that was more evident in the case of articles on scavenging. The species reported in both predation and scavenging articles were mainly wild and domestic mammals with high meat-based diets and nocturnal habits, and the majority of the studies were conducted in the interior zone of cities compared to peri-urban areas. Understanding the trophic role of carnivores in urban environments and its ecological consequences will require full recognition of both their predation and scavenging facets, which is especially desirable given the urban sprawl that has been predicted in the coming decades.