Non-volant mammals of Carlos Botelho State Park, Paranapiacaba Forest Continuum

Linking howler monkey ranging and defecation patterns to primary and secondary seed dispersal

To define the chances of a dispersed seed to produce a new recruit, it is essential to consider all stages of the dispersal process. Howler monkeys are recognized to have positive impacts on forest regeneration, acting as primary dispersers. Furthermore, dung beetles attracted to their feces protect the seeds against predators, and provide a better microenvironment for germination due to the removal of fecal matter, to seed burial, and/or by reducing the spatial aggregation of seeds in fecal clumps. Despite the recognized positive effects of primary seed dispersal through defecation by howler monkeys for plant recruitment, there are some important aspects of their behavior, such as the habit of defecating in latrines, that remain to be explored. Here, we investigated the fate of Campomanesia xanthocarpa seeds defecated by brown howlers, Alouatta guariba clamitans, and the secondary seed dispersal by dung beetles, considering how this process is affected by the monkey's defecation patterns. We found that brown howler monkeys dispersed seeds from several species away from fruit-feeding trees, partly because defecation under the canopy of such trees was not very frequent. Instead, most defecations were associated with latrines under overnight sleeping trees. Despite a very similar dung beetle community attracted to howler feces in latrines and fruit-feeding sites, seeds were more likely to be buried when deposited in latrines. In addition, C. xanthocarpa seeds showed higher germination and establishment success in latrines, but this positive effect was not due to the presence of fecal matter surrounding seeds. Our results highlight that A. guariba clamitans acts as a legitimate seed disperser of C. xanthocarpa seeds in a preserved context of the Brazilian Atlantic Forest and that defecations in latrines increase the dispersal effectiveness.

Estimates of Species Richness and Composition Depend on Detection Method in Assemblages of Terrestrial Mammals

Detecting rapid changes in mammal composition at large spatial scales requires efficient detection methods. Many studies estimate species composition with a single survey method without asking whether that particular method optimises detection for all occurring species and yields reliable community-level indices. We explore the implications of between-method differences in efficiency, consistency, and sampling effort for the basic characterisation of assemblages of medium to large mammals in a region with three contrasted Mediterranean landscapes. We assessed differences between camera traps, scent stations, scat surveys, and track surveys. Using track surveys, we detected all species present in the regional pool (13) and obtained the most accurate description of local species richness and composition with the lowest sampling effort (16 sampling units and 2 survey sessions at most). Had we chosen camera traps, scent stations, or scat surveys as the only survey method, we would have underestimated species richness (9, 11, and 12 species, respectively) and misrepresented species composition in varying degrees. Preliminary studies of method performance inform whether single or multiple survey methods are needed and eventually which single method might be most appropriate. Without such a formal assessment current practices may produce unreliable and incomplete species inventories, ultimately leading to incorrect conclusions about the impact of human activity on mammal communities.

Species composition of small non-volant mammals in the Parque Estadual das Fontes do Ipiranga, São Paulo, Brasil

Abstract: This study provides the first inventory of small non-volant mammals in the Parque Estadual das Fontes do Ipiranga (PEFI), a protected area in the city of São Paulo, Brazil. The data was collected from 2015 to 2017 in 16 research campaigns with a duration of five days each. Four areas with different phytophysiognomies were sampled throughout the dry and rainy seasons. We sampled small mammals using live-capture and pitfall traps. Eleven species were captured, composed of six rodents and five marsupials. The sampling effort involved 5,600 traps/night, there were 527 capture events, and we captured 302 distinct individuals: 174 marsupials and 128 rodents. Recaptures accounted for 42.7% of the total captures. No significant differences were observed in the richness and abundance of small non-volant mammals between the different phytophysiognomies. We also found no significant differences in the richness and abundance of small non-volant mammals between the dry and rainy seasons. The relative abundance (Ar) and constancy index (C) of the species showed that the three most abundant and common species in the PEFI are: Didelphis aurita, Akodon montensis and Oligoryzomys nigripes, which represented 93.7% of the captures. Tomahawk traps accounted for 69% of the total captures, and pitfall traps were responsible for detecting the greatest richness, capturing 81.8% of the species. Comparing the efficiency of the different sampling methods in capturing small mammals in the PEFI, we observed significant differences between both pitfall versus Tomahawk and pitfall versus Sherman in the understory. The results obtained in this study are consistent with the past and current situations of the forest fragment which are in recovery after significant altered by anthropic activity. In light of this scenario of degradation and isolation, a defaunation process affecting the mastofauna is very likely in the PEFI, which favors the establishment and dominance of generalist species. This study could be the basis for further monitoring programs of small non-volant mammals. The data obtained here will also increase knowledge about the diversity of small mammals in urban fragments of the Atlantic Forest and demonstrate the importance of the PEFI for the maintenance of ecologically important species within the largest metropolitan region in Brazil. These species play important biological roles for the maintenance of ecological interactions and for the provision of rare ecosystem services for the anthropic landscape, which is of great value to the city of São Paulo.

Seroprevalence and incidence of Toxoplasma gondii and Neospora caninum infection in naturally exposed domestic dogs from a rural area of São Paulo state, Brazil

Dogs are hosts of the protozoans Toxoplasma gondii, which causes an important public health disease, and Neospora caninum. Studies that have evaluated toxoplasmosis and neosporosis for prolonged periods in dog populations are rare. We analyzed infection by both parasites in a domestic dog population over three consecutive years in São Paulo state, Brazil. In the 1st, 2nd and 3rd years of collection, 181, 193 and 172 domiciles were visited, and blood samples of 331, 371 and 348 dogs were collected for antibody serology, respectively. The seroprevalence of T. gondii in each year was 27.2%, 22.5% and 43.9%, respectively, and that of N. caninum was 7.8%, 4.8% and 6.8%, respectively. The incidence rates for T. gondii in the 2nd and 3rd collections were 13.2% and 30.0%, and those for N. caninum were 3.3% and 4.4%, respectively. Positive and negative serological conversions for both agents occurred at high frequencies during the study period. This study reveals the canine population's serological profile and demonstrates the constant exposure of dogs to the investigated pathogens, indicating the need for prevention and control measures in the region.

Potential impact of mammal defaunation on the early regeneration of a large-seeded palm in the Brazilian Atlantic Forest

Defaunation, the decline in animal species and populations, is biased towards large-bodied animals that have unique roles as dispersers of large seeds. However, it is speculated that these roles may still be performed by smaller animals, such as small mammals like rodents and marsupials, that thrive in defaunated sites. We investigated if small mammals can disperse the large-seeded palm Attalea dubia. We performed the study in a well-conserved Atlantic Forest remnant in southeast Brazil that still harbours large mammals, such as tapirs. Focal observations showed that capuchin-monkeys consumed the mesocarp of the fruits and dropped the seeds beneath the plant crown thereafter. Mammals preyed on ca. 1% and removed ca. 15% of the fallen fruit/seed and deposited them up to 15 m away. Amongst them, small mammals (< 1 kg), such as the squirrel Guerlinguetus brasiliensis and non-identified nocturnal Sigmodontinae, as well as the marsupial Philander frenatus performed the bulk of interactions. Dispersal enhances recruitment, but the short distances of seed removal did not match the current spatial distribution of palm seedlings and juveniles. Recaching rates of hoarded seeds were small (2%) and unlikely to increase distances of seed dispersal achieved. Short distances of dispersal would increase plant clumpiness and negative density-dependent effects with time. Although small mammals can provide legitimate dispersal, they cannot fully replace larger frugivorous mammals and maintain long-distance seed dispersal that feeds plant metapopulation dynamics and seed gene flow.

Testing camera traps as a potential tool for detecting nest predation of birds in a tropical rainforest environment

Identification of the predators of bird nests is essential to test ecological and evolutionary hypotheses and to make practical management decisions. A variety of nest monitoring devices have been proposed but many remain difficult to set up in the field. The aim of this study was to test camera traps as a potential tool to study predation of natural nests in a tropical rainforest environment. Specifically, we registered the predators, assessed their size range, and we compared the use of one and two cameras per nest. Of 122 nests from 24 bird species, 45 (37%) were depredated, and the cameras recorded the predator species in 29 of the total of depredated nests (64%). We identified predators in eight of 16 depredated nests (50%) in which we used one camera trap per nest, and we identified predators in 21 of 29 depredated nests (72%) when we used two camera traps per nest. The predators included six species of birds and six species of mammals, with body masses varying from 20 g to 16.5 kg. Causes for 10 of the 16 detection failures were identified and are discussed. These results suggest that camera traps are viable tools to investigate nest predation in a tropical rainforest area.

Testing camera traps as a potential tool for detecting nest predation of birds in a tropical rainforest environment

Identification of the predators of bird nests is essential to test ecological and evolutionary hypotheses and to make practical management decisions. A variety of nest monitoring devices have been proposed but many remain difficult to set up in the field. The aim of this study was to test camera traps as a potential tool to study predation of natural nests in a tropical rainforest environment. Specifically, we registered the predators, assessed their size range, and we compared the use of one and two cameras per nest. Of 122 nests from 24 bird species, 45 (37%) were depredated, and the cameras recorded the predator species in 29 of the total of depredated nests (64%). We identified predators in eight of 16 depredated nests (50%) in which we used one camera trap per nest, and we identified predators in 21 of 29 depredated nests (72%) when we used two camera traps per nest. The predators included six species of birds and six species of mammals, with body masses varying from 20 g to 16.5 kg. Causes for 10 of the 16 detection failures were identified and are discussed. These results suggest that camera traps are viable tools to investigate nest predation in a tropical rainforest area.

Synergistic effects of seed disperser and predator loss on recruitment success and long-term consequences for carbon stocks in tropical rainforests

The extinction of large frugivores has consequences for the recruitment of large-seeded plants with potential lasting effects on carbon storage in tropical rainforests. However, previous studies relating frugivore defaunation to changes in carbon storage ignore potential compensation by redundant frugivores and the effects of seed predators on plant recruitment. Based on empirical data of the recruitment success of a large-seeded hardwood tree species (Cryptocarya mandioccana, Lauraceae) across a defaunation gradient of seed dispersers and predators, we show that defaunation increases both seed dispersal limitation and seed predation. Depending on the level of seed predator loss, plant recruitment is reduced by 70.7–94.9% as a result of the loss of seed dispersers. The loss of large seed predators increases the net seed mortality by 7–30% due to the increased abundance of small granivorous rodents. The loss of large seed dispersers can be buffered by the compensatory effects of smaller frugivores in seed removal, but it is not sufficient to prevent a decrease in plant recruitment. We show that the conservation of both seed predators and dispersers is necessary for the recruitment of large-seeded plants. Since these plants contribute substantially to carbon stocks, defaunation can jeopardize the maintenance of tropical forest carbon storage.

Trophic Niche Differentiation in Rodents and Marsupials Revealed by Stable Isotopes

Tropical rainforests support the greatest diversity of small mammals in the world, yet we have little understanding about the mechanisms that promote the coexistence of species. Diet partitioning can favor coexistence by lessening competition, and interspecific differences in body size and habitat use are usually proposed to be associated with trophic divergence. However, the use of classic dietary methods (e.g. stomach contents) is challenging in small mammals, particularly in community-level studies, thus we used stable isotopes (δ¹³C and δ¹⁵N) to infer about trophic niche. We investigated i) how trophic niche is partitioned among rodent and marsupial species in three Atlantic forest sites and ii) if interspecific body size and locomotor habit inequalities can constitute mechanisms underlying the isotopic niche partitioning. We found that rodents occupied a broad isotopic niche space with species distributed in different trophic levels and relying on diverse basal carbon sources (C3 and C4 plants). Surprisingly, on the other hand, marsupials showed a narrow isotopic niche, both in δ¹³C and δ¹⁵N dimensions, which is partially overlapped with rodents, contradicting their description as omnivores and generalists proposed classic dietary studies. Although body mass differences did not explained the divergence in isotopic values among species, groups of species with different locomotor habit presented clear differences in the position of the isotopic niche space, indicating that the use of different forest strata can favor trophic niche partitioning in small mammals communities. We suggest that anthropogenic impacts, such as habitat modification (logging, harvesting), can simplify the vertical structure of ecosystems and collapse the diversity of basal resources, which might affect negatively small mammals communities in Atlantic forests.

Aves do Parque Estadual Carlos Botelho – SP

O inventário da biodiversidade nas unidades de proteção integral implantadas em remanescentes da Mata Atlântica, além de ampliar o conhecimento sobre a distribuição das espécies, pode contribuir para ações de monitoramento e manejo que aprimorem a conservação dos ecossistemas. Os objetivos desse trabalho foram caracterizar as assembleias de aves do Parque Estadual Carlos Botelho, sudeste do estado de São Paulo, quanto à composição de espécies, abundância relativa e associação com fitofisionomias locais. A amostragem foi realizada entre abril de 2006 e dezembro de 2009 pelo método de trajetos de distância ilimitada, totalizando 1000 horas de esforço amostral. Foram registradas 331 espécies, predominando formas florestais residentes e com abundância relativa inferior a 100 detecções. Vinte e cinco espécies estão ameaçadas de extinção no estado de São Paulo.