Habitat patch and matrix effects on small-mammal persistence in Amazonian forest fragments

Abstract

Tropical forest mammal assemblages are widely affected by the twin effects of habitat loss and habitat fragmentation. We evaluated the effects of forest patch metrics, habitat structure, age of patch isolation, and landscape metrics on the species richness, abundance and composition of small mammals at 23 forest fragments (ranging in size from 43 to 7,035 ha) in a highly deforested 3,609-km2 landscape of southwestern Brazilian Amazonia. Using pitfall traps and both terrestrial and arboreal traplines of Sherman, Tomahawk and snap traps, we captured a total of 844 individuals over 34,900 trap-nights representing 26 species and 20 genera of small-mammals, including 13 rodent and 13 marsupial species. We also consider the effects of distance from forest edges on species occupancy and abundance. Overall small mammal abundance, species richness and species composition were primarily affected by the quality of the open-habitat matrix of cattle pastures, rather than by patch metrics such as fragment size. Ultimately, small mammal community structure was determined by a combination of both landscape- and patch-scale variables. Knowledge of the anthropogenic factors that govern small mammal community structure is of critical importance for managing the persistence of forest vertebrates in increasingly fragmented neotropical forest landscapes

Effects of roads on the vertebrates diversity of the Indigenous Territory Paresi and its surrounding

“…This number is higher than the value of 0.017 found for the roads PR-406 and PR-508, on the coast plains of the state of Paraná (Leite et al, 2012), and 0.014 on the GO 060 road, stretch Goiânia-Iporã (Moreira et al, 2006), which have vegetation similar to the one found on highway MT-358. This may indicate that there are a higher number of vertebrates in the Cerrado/Amazon transition area when compared to other areas, such as the Atlantic Forest or the Cerrado, as seen in studies by Van Der Laan (2012) and Santos-Filho et al (2012), or that the animal communities are restructuring themselves because of deforestation.…”

“…Santos-Filho et al (2012), while studying the seasonal variation of vertebrate roadkills on highway 354 in Minas Gerais, also registered amphibian roadkills only during rainy months. These roadkills contributed to a general increase in the number of roadkills, causing one of the highest peaks registered during all the months of data collection.…”

Trap efficiency evaluation for small mammals in the southern Amazon

“…Richness and abundance of small mammals are more accurately estimated when using more than one type of trap, such as Shermans, Tomahawks, youngs and snap traps (Voss et al 2001;Pardini 2004;Santos-Filho et al 2012). Previous studies showed that Pitfall traps are more effective than conventional traps (Nicolas and Colyn 2006;Umetsu et al 2006), however Pitfalls are rarely used for sampling small mammals in tropical forests.…”

Forest Fragmentation in the Lower Amazon Floodplain: Implications for Biodiversity and Ecosystem Service Provision to Riverine Populations

“…In relation to edge area, it is calculated that 83% of abundance and 74% of mammal richness are explained by this parameter [56]. The most significant impacts are felt in the first 180 m of edge, which exhibit up to 94% less abundance and 78% less richness than the forest interior [57].…”