Efficiency of eDNA and iDNA in assessing vertebrate diversity and its abundance.

Environmental DNA (eDNA) and invertebrate-derived DNA (iDNA) have been increasingly recognized as powerful tools for biodiversity assessment and conservation management. However, eDNA/iDNA efficiency for vertebrate diversity assessment remains uncertain, and comparisons to conventional methods are still rare. Through a meta-analysis of previously published vertebrate diversity surveys, we compared the efficiency of eDNA/iDNA against conventional methods across several types of samplers, vertebrate groups, and locations (tropical vs. temperate zones). We also assess eDNA/iDNA efficiency to estimate relative abundance or biomass over different molecular methods (qPCR and metabarcoding) and type of experiment (in the laboratory or in the field). We showed that for water sampler, fish as a target species, and studies achieved in temperate zones, eDNA presents lower risk of not detecting a species or a site with a target species than conventional methods. These results show that eDNA is an efficient tool to assess fish diversity. Moreover, eDNA data presents positive correlation with fish abundance or biomass. However, such correlation was higher in laboratory experiments than in the field. For the other samplers, vertebrate groups, and in tropical zones we were not able to draw general conclusion, highlighting the urgency of conducting more comparative studies.

Non-invasive genetic sampling reveals a habitat use extension of Chrysocyon brachyurus and Leopardus guttulus inside a protected area of Southeastern Brazil / Amostragem genética não-invasiva revela uma extensão do uso de habitat por Chrysocyon brachyurus e Leopardus guttulus em uma área protegida do Sudeste do Brasil

Abstract Anthropogenic activities have modified landscapes leading to environmental damages and to a threatened biodiversity. As a result, protected areas have become the last refuge for many species. Protected areas surrounded by a highly modified landscape may accumulate species, especially large mammals, which may alter their habitual habitat use. Here we used non-invasive DNA analysis, molecular species identification, and landscape analyses to assess the habitat use of carnivore species in an isolated protected area, Itatiaia National Park (PNI). Two species were by far the most sampled within PNI, Chrysocyon brachyurus and Leopardus guttulus. The spatial distribution of each species was assessed to the following landscape variables: altitude; land use/land cover; slope and Euclidean distances from water and from urban buildings. The habitat use of C. brachyurus and L. guttulus was related to altitude and land use/land cover. We tested whether there were differences in the environmental indicators considering both species, which showed that higher altitudes, forest and/or grassland formation were indeed associated with them. We highlighted the unprecedented presence of both species at altitudes up to 2,631 meters. Our results suggest a habitat use extension for both species inside the PNI that could be a consequence of the highly modified landscape where PNI is inserted. Therefore, the results can be helpful for better understanding the species dynamics and their conservation in the face of landscape changes. Further, this study may be of help for management and conservation policies of this emblematic protected area.

Resumo As atividades antropogênicas modificaram as paisagens levando a danos ambientais e a uma biodiversidade ameaçada. Como resultado, as áreas protegidas se tornaram o último refúgio para muitas espécies. Áreas protegidas cercadas por uma paisagem altamente modificada podem acumular espécies, especialmente grandes mamíferos, o que pode alterar o uso de seu habitat habitual. Neste trabalho, usamos análise de DNA não-invasivo, identificação molecular de espécies e análises de paisagem para avaliar o uso de habitat de carnívoros em uma área protegida isolada, o Parque Nacional de Itatiaia (PNI). Duas espécies foram de longe as mais amostradas dentro do PNI, Chrysocyon brachyurus e Leopardus guttulus. A distribuição espacial de cada espécie foi avaliada com as seguintes variáveis paisagísticas: altitude; uso e cobertura do solo; declividade e distâncias euclidianas da água e de construções urbanas. O uso de C. brachyurus e L. guttulus no habitat estava relacionado à altitude e ao uso e cobertura do solo. Testamos se existiam diferenças nos indicadores ambientais considerando ambas as espécies, o que mostrou que altitudes mais elevadas, formação de florestas e/ou campestres estavam de fato associadas a elas. Destacamos a presença incomum de ambas as espécies em altitudes de até 2.631 metros. Nossos resultados sugerem uma extensão do uso do habitat conhecido para ambas as espécies como possível consequência da paisagem altamente modificada onde o PNI está inserido. Portanto, os resultados podem ser úteis para entender melhor a dinâmica das espécies e sua conservação diante das mudanças na paisagem. Além disso, este estudo pode ser útil para as políticas de manejo e conservação desta emblemática área protegida.