Ingrid de Mattos

1. Fragmentation and habitat loss are responsible for declines in biodiversity and alterations in ecological processes worldwide [1–3]. Reduction in patch area, increased isolation, greater edge ef...

Habitat loss and fragmentation have notable effects on species' trophic ecology, often most pronounced in landscapes with intermediate levels of remaining habitat, where patch configuration can vary significantly. We assessed how habitat fragmentation influences the carbon‐ and nitrogen‐based isotopic niche space of the agile opossum ( Gracilinanus agilis ) across landscapes with varying habitat loss in semideciduous dry forests in central Brazil. We found that δ ¹³ C values did not vary with patch size or habitat loss, suggesting a consistent reliance on forest resources. The opossum exhibited a niche shift only in intermediate and more conserved landscapes, transitioning from insectivory to frugivory in small and large patches, respectively, with a stronger effect in intermediate landscapes. In the most degraded landscape, niche width expanded in smaller patches, likely due to the inclusion of less valuable dietary items in a context of limited food availability and high forager density. Conversely, there was a niche expansion towards larger patches as one moved from intermediate to more conserved landscapes. This shift was attributed to higher resource availability and diversity in areas with better habitat quality and increased forest complexity. There is clear evidence that fragmentation and habitat loss modify the trophic niche of G. agilis , potentially hampering its ecological role as a seed disperser, especially in more degraded landscapes. Although the opossum exhibits high adaptability to landscape alterations through trophic plasticity, even small patches might be crucial for their populations in highly fragmented landscapes due to their reliance on forest resources.

Landscape conversion of natural environments into agriculture and pasture are driving a marked biodiversity decline in the tropics. Consequences of fragmentation might depend upon habitat amount in the landscape, while the quality of remnants can also affect some species. These factors have been poorly studied in relation to different spatial scales. Furthermore, the impacts of these human-driven alterations may go beyond species loss, possibly causing a loss of ecosystem function and services. In this study, we investigated how changes in landscape configuration (patch size and isolation), habitat loss (considering a landscape gradient of 10, 25, and 40% of remnant forest cover), and habitat quality (forest structure) affect small mammal abundance, richness, taxonomic/functional diversity, and species composition in fragmented landscapes of semideciduous forests in the Brazilian Cerrado. Analyses were performed separately for habitat generalists and forest specialists. We live-trapped small mammals and measured habitat quality descriptors four times in 36 forest patches over the years 2018 and 2019, encompassing both rainy and dry seasons, with a total capture effort of 45,120 trap-nights. Regression analyses indicated that the effect of landscape configuration was not dependent on the proportion of habitat amount in the landscape to determine small mammal assemblages. However, both patch size and habitat loss impacted different aspects of the assemblages in distinct ways. Smaller patches were mainly linked to an overall increase in small mammal abundance, while the abundance of habitat generalists was also negatively affected by habitat amount. Generalist species richness was determined by the proportion of habitat amount in the landscape. Specialist richness was influenced by patch forest quality only, suggesting that species with more demanding habitat requirements might respond to fragmentation and habitat loss at finer scales. Taxonomic or functional diversity were not influenced by landscape structure or habitat quality. However, patch size and habitat amount in the landscape were the major drivers of change in small mammal species composition in semideciduous forests in the Brazilian savanna.

The state of Goiás, in central Brazil, is covered mainly by the Cerrado domain, with the Alto Paraná Atlantic Forest occupying its central-southern portion. Goiás is one of the 20 Brazilian federative units without a mammal checklist. In this study, we provide the first checklist of mammals from Goiás state. We recorded mammal species based primarily on the analysis of specimens housed in scientific collections as well as on literature with associated voucher material. We listed 191 mammalian species belonging to 125 genera, 31 families and 10 orders, which represents 25.2% of the mammal species occurring in Brazil. The most speciose orders were Chiroptera (90 spp.), followed by Rodentia (43 spp.), Carnivora (19 spp.) and Didelphimorphia (17 spp.). The following orders accounted for a smaller portion of the state diversity: Cetartiodactyla (7 spp.), Cingulata (7 spp.), Primates (4 spp.), Pilosa (2 spp.), Lagomorpha (1 sp.), and Perissodactyla (1 sp.). A total of 28 species (14.7%), mainly represented by medium and large-sized mammals, are nationally threatened while 12 (6.3%) are globally threatened. Our results indicate great portions of the state lacking a proper survey of mammals, especially the northwestern portion. We discuss species richness, distribution and conservation status of the mammals of Goiás state in national and regional scenarios. We highlight the need for mammal inventories based on complementary survey techniques with the collection of vouchers in order to provide karyologic, molecular, morphologic, parasitologic, and ecological data. These informations are the basis for integrative studies that lead to the understanding of current mammalian richness and diversity. Indeed, knowledge on species richness distribution in the state will guide conservation strategies, especially in areas undergoing habitat loss and fragmentation, such as the central-southern portion of Goiás.