Does stress mess with rodents' heads? Influence of habitat amount and genetic factors in mandible fluctuating asymmetry in South American water rats (Nectomys squamipes, Sigmodontinae) from Brazilian Atlantic rainforest remnants.

Loss of developmental stability can lead to deviations from bilateral symmetry (i.e. Fluctuating Asymmetry - FA), and is thought to be caused by environmental and genetic factors associated with habitat loss and stress. Therefore, levels of FA might be a valuable tool to monitor wild populations if FA serves as an indicator of exposure to stress due to impacts of habitat loss and fragmentation. In studies examining FA and habitat fragmentation, FA levels are often explained by loss of genetic variation, though few studies have addressed FA's use as indicator of environmental impact. Here, we investigated whether habitat loss, genetic variation, and/or inbreeding affect the developmental instability in Brazilian Atlantic forest populations of a Neotropical water rat (Nectomys squamipes). We sampled individuals from eight sites within Atlantic forest remnants with different amounts of available forest habitat and assessed FA levels with geometric morphometric techniques using adult mandibles. We used observed heterozygosity (Ho) and inbreeding coefficient (Fis), from seven microsatellite markers, as a proxy of genetic variation at individual and population levels. Populations were not significantly different for shape or size FA levels. Furthermore, interindividual variation in both shape and size FA levels and interpopulational differences in size FA levels were best explained by chance. However, habitat amount was negatively associated with both interpopulational variance and average shape FA levels. This association was stronger in populations living in areas with <28% of forest cover, which presented higher variance and higher average FA, suggesting that Nectomys squamipes might have a tolerance threshold to small availability of habitat. Our work is one of the first to use FA to address environmental stress caused by habitat loss in small mammal populations from a Neotropical biome. We suggest that shape FA might serve as a conservation tool to monitor human impact on natural animal populations.

Expansion of the range of Necromys lasiurus (Lund, 1841) into open areas of the Atlantic Forest biome in Rio de Janeiro state, Brazil, and the role of the species as a host of the hantavirus.

Necromys lasiurus is a generalist rodent that is thought to be the main reservoir of the Araraquara hantavirus, which causes Hantavirus Pulmonary Syndrome, in the Brazilian Cerrado savanna. This species occurs naturally in the open habitats of the Cerrado, Pantanal and Caatinga biomes, where it often occurs at high densities, although the distribution of the species has recently been observed expanding into the Brazilian state of Rio de Janeiro. This study aimed to map the occurrence of N. lasiurus within the Atlantic Forest of Rio de Janeiro state and discuss the potential role of the species as a reservoir of the Araraquara hantavirus in these areas. The study was based on a comprehensive literature search and four expeditions for the collection of specimens in the state of Rio de Janeiro. The data were used to predict the distribution of N. lasiurus, confirm the distribution of the species in the state, and detect the rates of hantavirus infection in these rodents. Necromys lasiurus has been recorded at 16 localities in 10 municipalities of Rio de Janeiro state. The relative abundance of N. lasiurus was low at all localities, except for the REBIO Poço das Antas and APA-BRSJ, two protected areas. Necromys lasiurus was associated primarily with landscapes dominated by farmland (plantations or pasture) at relatively low altitudes in the vicinity of bodies of water. A total of 204 serum samples were collected, but none were reactive for hantavirus. The distribution of N. lasiurus is expanding into many areas of the anthropogenic matrix, but it is not usually either abundant or dominant in these areas. The relatively reduced abundance of N. lasiurus in Rio de Janeiro and the lack of infection in all the areas investigated indicate that it is unlikely to be a reservoir of hantavirus in this region in the near future.

Barn Owl pellets (Aves: Tyto furcata) reveal a higher mammalian richness in the Restinga de Jurubatiba National Park, Southeastern Brazil / Pelotas de coruja suindara (Aves: Tyto furcata) revelam uma elevada riqueza de mamiferos no Parque Nacional da Restinga de Jurubatiba, Sudeste do Brasil

The northern coast of the state of Rio de Janeiro harbors the largest coastal sandy plains (restingas) of southeastern Brazil, severely threatened due to recent human occupation. In this context, mammal inventories becomes urgent to support biodiversity conservation and management policies. This paper aims to update the knowledge on the mammalian species richness of Restinga de Jurubatiba National Park by analyzing pellets of the Barn owl Tyto furcata. The analyses of 4745 mammalian bone fragments (1739 individuals) revealed the occurrence of 17 species belonging to the orders Rodentia (9 spp.), Didelphimorphia (2 spp.) and Chiroptera (6 spp.). The rodents Mus musculus and Cerradomys goytaca accounted for 77.2% of the total individuals preyed, suggesting that the Barn owl hunts in both disturbed and natural open shrub formations. A compilation of previous records, together with those provided in the present study, indicates the occurrence of 44 species of mammals in the Restinga de Jurubatiba National Park, of which six (13.6%) were exclusively detected in pellets. These new records include species adapted to open formations of the interior of Brazil that were not previously reported in restingas on the basis of voucher-specimens, such as the rodents Necromys lasiurus and Calomys tener, the latter being recorded for the first time in the littoral of Rio de Janeiro state. This study underscores the importance of owl pellet analysis as a complementary and indispensable method for inventorying mammals. The results highlight the Restinga de Jurubatiba National Park as one of the restingas in Southeastern Brazil with the highest number of mammal species.

O litoral norte do estado do Rio de Janeiro possui a maior planície deltaica recoberta por restingas do sudeste brasileiro, porém sob intensa ameaça devido è ocupação humana recente. Neste contexto, a realização de inventários torna-se urgente para fortalecer políticas de manejo e conservação ambiental. Esse trabalho teve como objetivo complementar inventários mastofaunísticos do Parque Nacional da Restinga de Jurubatiba através da utilização de pelotas da coruja suindara Tyto furcata. A análise de 4745 fragmentos ósseos de mamíferos (1739 indivíduos) revelou a ocorrência de 17 espécies pertencentes ès ordens Rodentia (9 spp.), Didelphimorphia (2 spp.) e Chiroptera (6 spp.). Os roedores Mus musculus e Cerradomys goytaca foram responsáveis por 77,2% do total de indivíduos predados, sugerindo que a suindara caça tanto em ambientes peridomiciliares perturbados como em formações naturais arbustivas da restinga. A compilação de registros anteriores com os fornecidos pelo presente estudo indica a ocorrência de 44 espécies de mamíferos no Parque Nacional da Restinga de Jurubatiba, dentre as quais seis (13.6%) foram exclusivamente detectadas em pelotas. Dentre estes novos registros, destaca-se a presença de espécies adaptadas a formações abertas do interior do Brasil que não tinham sua ocorrência documentada em restingas a partir de espécimes-testemunho, como os roedores Necromys lasiurus e Calomys tener, esta última registrada pela primeira vez no litoral do estado do Rio de Janeiro. Esse estudo corrobora a importância das análises de pelotas de coruja como método complementar e imprescindível em inventários de mamíferos, além de destacar o Parque Nacional da Restinga de Jurubatiba como uma das restingas mais ricas em espécies de mamíferos do sudeste brasileiro.