Non-volant mammalian species richness in the ecotonal Brazilian midnorth: checklist for Maranhão State

Abstract

<jats:p>Abstract: The state of Maranhão, located in the westernmost portion of the Northeast Region of Brazil, is characterized by a dynamic and unstable ecotone among the Amazon, Caatinga and Cerrado biomes that presents a high degree of biodiversity with high vulnerability to anthropogenic activities. Despite the enormous potential for sheltering high levels of species diversity and abundance, little is known about many aspects the state’s biodiversity, especially with regard to mammalian fauna. A capture-recapture methodology using live-traps was employed to inventory the non-volant, small mammal community. In addition, we recorded medium and large mammals based on direct and indirect observations, camera-trap surveys, and interviews. An extensive literature search of published research was also performed to maximize the elaboration of a complete mammal species checklist for Maranhão. A total of 89 non-volant mammal species, representing 9 orders and 27 families were recorded in the state of Maranhão. Of these taxa, 25.84% are included in the Brazilian Red List for endangered species, while 20 are considered as being endemic to Brazil. The preservation status of some areas, coupled with the strong presence of agro-pastoral environments, contributed to some unusual species occurrences, while the state’s ecotonal nature was noted by the numbers of species associated with the Amazon (N=65) and Cerrado (N=66) biomes.. Given the rapid development and effects of numerous anthropogenic impacts occurring in the state, it is a crucial time to quantify, even at specific scales, the environmental richness of Maranhão. The significant levels of biodiversity, high degree of endemism, and the presence of numerous rare and endangered species characterizes Maranhão as being among the most biologically important parts of Brazil. Nonetheless, many gaps in our basic knowledge regarding the biodiversity of this area remain, such that the execution of additional biological inventories is imperative, as are greater efforts to clarify certain species limits and necessary taxonomic revisions, most notably that for small mammals.</jats:p>

Potential mammalian species for investigating the past connections between Amazonia and the Atlantic Forest

“…Hence, sampling deficiencies in the north-eastern dry diagonal, in addition to the non-inclusion of specimens deposited in museum collections or published records of species in this region [ 24 ] may have led to faulty estimates of the number of potential taxa that could have spread along the Eastern route. As new records appear with increased sampling effort through systematic biogeographic studies in this region, future reassessments will thus, almost certainly, find additional species, which evidence past dispersions along the Eastern route [ 69 – 73 , 76 ]. For example, several recent studies have presented new records of common forest species, such as for marsupials [ 74 – 77 ] and rodents [ 78 , 79 ] along the Eastern route.…”

Avaliação da Efetividade da Reserva Biológica do Gurupi na Conservação de Vertebrados Terrestres de Médio e Grande Porte

“…Os quatro anos de monitoramento resultaram num esforço amostral de 13.020 armadilhas-dia e 114.199 fotos de animais (Tabela 1). Considerando somente os vertebrados terrestres de médio e grande porte que atenderam aos critérios para inclusão no presente estudo, foram registradas 36 espécies, sendo 10 de aves e 26 de mamíferos (Tabela 2), o que equivale a 72% das aves e 96% dos mamíferos de médio e grande porte registrados na Amazônia maranhense (Oren & Roma, 2011;Lima et al, 2015;Vieira & Oliveira 2020). Treze espécies (36%) constam da lista oficial brasileira de espécies ameaçadas de extinção de acordo com a Portaria MMA 444/2014 (MMA, 2014; Tabela 2).…”

“…Portanto, foram considerados somente os registros de mamíferos terrestres >1kg de massa corporal e as aves terrestres cinegéticas >0,3kg das famílias Cracidae, Odontophoridae, Psophiidae e Tinamidae. A referência da massa Análises dos dados -A composição e riqueza de espécies foram analisadas a partir do inventário das espécies registradas pelo monitoramento e de sua comparação com as listas de espécies de ocorrência na Amazônia maranhense apresentadas em Oren & Roma (2011), Lima et al (2015), Vieira & Oliveira (2020), permitindo avaliar a representatividade da UC em relação a riqueza de vertebrados terrestres de médio e grande porte da região.…”

Potential mammalian species for investigating the past connections between Amazonia and the Atlantic Forest

“…The rodent Oecomys catherinae , considered restricted to the Atlantic Forest, has been recorded along the NE route [51, 52]. The black-eared opossum D. marsupialis presents disjunct distribution, but recent records point to no disjunction along the NE route [e.g., 49, 50, 53]. The three-striped short-tailed opossum, Monodelphis americana , is also present in the eastern Amazonia and in the northeastern Atlantic Forest, with the populations south of the São Francisco River belonging to another species of the genus Monodelphis [54].…”

“…Hence, updating the known distribution of these species and others would certainly increase the number of species showing evidence of the past connections between Amazonia and the Atlantic Forests, mainly through the NE route. Additionally, as new records appear with increased sampling and systematic biogeographic studies from the NE region, future reassessments will certainly find further species showing evidence of past dispersions along the NE route [e.g., 47, 48, 53].…”