Ana Maria de Oliveira Paschoal

Is the domestic dog becoming an abundant species in the Atlantic forest? A study case in southeastern Brazil.

Abstract 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.

Ocelot Population Status in Protected Brazilian Atlantic Forest

Forest fragmentation and habitat loss are detrimental to top carnivores, such as jaguars (Panthera onca) and pumas (Puma concolor), but effects on mesocarnivores, such as ocelots (Leopardus pardalis), are less clear. Ocelots need native forests, but also might benefit from the local extirpation of larger cats such as pumas and jaguars through mesopredator release. We used a standardized camera trap protocol to assess ocelot populations in six protected areas of the Atlantic forest in southeastern Brazil where over 80% of forest remnants are < 50 ha. We tested whether variation in ocelot abundance could be explained by reserve size, forest cover, number of free-ranging domestic dogs and presence of top predators. Ocelot abundance was positively correlated with reserve size and the presence of top predators (jaguar and pumas) and negatively correlated with the number of dogs. We also found higher detection probabilities in less forested areas as compared to larger, intact forests. We suspect that smaller home ranges and higher movement rates in smaller, more degraded areas increased detection. Our data do not support the hypothesis of mesopredator release. Rather, our findings indicate that ocelots respond negatively to habitat loss, and thrive in large protected areas inhabited by top predators.

Factors associated with the seroprevalence of leishmaniasis in dogs living around Atlantic Forest fragments.

Canine visceral leishmaniasis is an important zoonosis in Brazil. However, infection patterns are unknown in some scenarios such as rural settlements around Atlantic Forest fragments. Additionally, controversy remains over risk factors, and most identified patterns of infection in dogs have been found in urban areas. We conducted a cross-sectional epidemiological survey to assess the prevalence of leishmaniasis in dogs through three different serological tests, and interviews with owners to assess features of dogs and households around five Atlantic Forest remnants in southeastern Brazil. We used Generalized Linear Mixed Models and Chi-square tests to detect associations between prevalence and variables that might influence Leishmania infection, and a nearest neighbor dispersion analysis to assess clustering in the spatial distribution of seropositive dogs. Our findings showed an average prevalence of 20% (ranging from 10 to 32%) in dogs. Nearly 40% (ranging from 22 to 55%) of households had at least one seropositive dog. Some individual traits of dogs (height, sterilization, long fur, age class) were found to positively influence the prevalence, while some had negative influence (weight, body score, presence of ectoparasites). Environmental and management features (number of cats in the households, dogs with free-ranging behavior) also entered models as negative associations with seropositivity. Strong and consistent negative (protective) influences of the presence of chickens and pigs in dog seropositivity were detected. Spatial clustering of cases was detected in only one of the five study sites. The results showed that different risk factors than those found in urban areas may drive the prevalence of canine leishmaniasis in farm/forest interfaces, and that humans and wildlife risk infection in these areas. Domestic dog population limitation by gonadectomy, legal restriction of dog numbers per household and owner education are of the greatest importance for the control of visceral leishmaniasis in rural zones near forest fragments.

Ecological interactions between ocelots and sympatric mesocarnivores in protected areas of the Atlantic Forest, southeastern Brazil

Fragmentation and habitat loss are top threats to tropical forest biodiversity and the Atlantic Forest is no exception. Over 80% of Atlantic Forest remnants in Brazil are < 50 ha and lack resident populations of large predators (jaguars, Panthera onca, and pumas, Puma concolor). Mesopredators with opportunistic life-history characteristics (e.g., ocelots, Leopardus pardalis) are now hypothesized to be the dominant competitor(s) in these systems and may negatively affect the spatial or temporal distribution of other sympatric mesocarnivores. We used camera-trap data, occupancy models, and temporal overlap indexes to explore whether ocelot occurrence influenced the habitat use or activity patterns of 6 mesocarnivores in reserves of the Brazilian Atlantic Forest. Ocelot occurrence did not influence the habitat use of these mesocarnivores. Moreover, the ability of some mesocarnivore species, especially the little spotted cat (L. guttulus), to adjust their activity patterns to avoid direct contact with ocelots may facilitate their coexistence in these Atlantic Forest remnants. Ocelot occurrence did not influence the activity pattern of 2 nocturnal species (the crab-eating fox, Cerdocyon thous, and the crab-eating raccoon, Procyon cancrivorus), suggesting that these species are more tolerant of ocelots than other mesocarnivores. The probability of occupancy varied among species, with tayra (Eira barbara) and South American coati (Nasua nasua) having the highest occupancy estimates; overall, occupancy by mesocarnivores correlated negatively with reserve size. Because mesocarnivores are important drivers of ecosystem function, structure, and dynamics and may occupy unique roles that cannot be filled by larger carnivores, future studies should assess environmental factors influencing the use of these small remnants of Atlantic Forest by each mesocarnivore species.

ATLANTIC‐CAMTRAPS: a dataset of medium and large terrestrial mammal communities in the Atlantic Forest of South America

Our understanding of mammal ecology has always been hindered by the difficulties of observing species in closed tropical forests. Camera trapping has become a major advance for monitoring terrestrial mammals in biodiversity rich ecosystems. Here we compiled one of the largest datasets of inventories of terrestrial mammal communities for the Neotropical region based on camera trapping studies. The dataset comprises 170 surveys of medium to large terrestrial mammals using camera traps conducted in 144 areas by 74 studies, covering six vegetation types of tropical and subtropical Atlantic Forest of South America (Brazil and Argentina), and present data on species composition and richness. The complete dataset comprises 53,438 independent records of 83 species of mammals, includes 10 species of marsupials, 15 rodents, 20 carnivores, eight ungulates and six armadillos. Species richness averaged 13 species (±6.07 SD) per site. Only six species occurred in more than 50% of the sites: the domestic dog Canis familiaris, crab-eating fox Cerdocyon thous, tayra Eira barbara, south American coati Nasua nasua, crab-eating raccoon Procyon cancrivorus and the nine-banded armadillo Dasypus novemcinctus. The information contained in this dataset can be used to understand macroecological patterns of biodiversity, community, and population structure, but also to evaluate the ecological consequences of fragmentation, defaunation, and trophic interactions.

Risk factors for gastrointestinal parasite infections of dogs living around protected areas of the Atlantic Forest: implications for human and wildlife health

Despite the ubiquity of domestic dogs, their role as zoonotic reservoirs and the large number of studies concerning parasites in urban dogs, rural areas in Brazil, especially those at the wildlife-domestic animal-human interface, have received little attention from scientists and public health managers. This paper reports a cross-sectional epidemiological survey of gastrointestinal parasites of rural dogs living in farms around Atlantic Forest fragments. Through standard parasitological methods (flotation and sedimentation), 13 parasite taxa (11 helminths and two protozoans) were found in feces samples from dogs. The most prevalent were the nematode Ancylostoma (47%) followed by Toxocara (18%) and Trichuris (8%). Other less prevalent (<2%) parasites found were Capillaria, Ascaridia, Spirocerca, Taeniidae, Acantocephala, Ascaris, Dipylidium caninum, Toxascaris, and the protozoans Cystoisospora and Eimeria. Mixed infections were found in 36% of samples, mostly by Ancylostoma and Toxocara. Previous deworming had no association with infections, meaning that this preventive measure is being incorrectly performed by owners. Regarding risk factors, dogs younger than one year were more likely to be infected with Toxocara, and purebred dogs with Trichuris. The number of cats in the households was positively associated with Trichuris infection, while male dogs and low body scores were associated with mixed infections. The lack of associations with dog free-ranging behavior and access to forest or villages indicates that infections are mostly acquired around the households. The results highlight the risk of zoonotic and wildlife parasite infections from dogs and the need for monitoring and controlling parasites of domestic animals in human-wildlife interface areas.

Anthropogenic Disturbances Drive Domestic Dog Use of Atlantic Forest Protected Areas

Domestic dog is the most successful invasive mammalian predator species, and reducing its ecological impacts on wildlife is a central conservation goal globally. Free-ranging dogs can negatively interact with wildlife at multiple levels, posing issues for biodiversity conservation in tropical forests, especially in fragmented Atlantic Forest. To optimize future control programs, it is necessary to identify the main factors influencing their habitat use, particularly in natural reserves. We combined camera trapping data and occupancy models to characterize habitat use of dogs in six Atlantic Forest protected areas (134–36,000 ha). Our results show that dogs were more likely to use sites ( Ψ ^  ≥ 0.90) having higher housing density (≥4.00 houses/km2) or higher proportion of croplands and pasture (≥75%) relative to sites with no houses ( Ψ ^  = 0.23 ± 0.10) or lower proportion of croplands and pasture ( Ψ ^  = 0.34 ± 0.08). In addition, dogs had higher detection probability at camera locations on unpaved roads ( p ^  = 0.33 ± 0.05) relative to off-road sites ( p ^  = 0.18 ± 0.04), and in small protected areas with high housing density, that is, more disturbed sites, dogs had higher detection probabilities. Our findings indicate that the probability of dogs using a site within protected area is mainly driven by type and intensity of human activity in the surroundings. Given the urgent need to control free-ranging dogs within protected areas, we strongly recommend that managers target sites/areas within and near protected areas that have a rural housing density ≥ 4.00 houses/km2 or higher proportion of croplands and pasture (≥75%).