Disturbance‐Mediated Mammal Persistence and Abundance‐Area Relationships in Amazonian Forest Fragments

Abstract

Few researchers have investigated the synergistic effects of tropical forest fragmentation and disturbance on species persistence and abundance. We examined effects of both forest-patch metrics and forest disturbance in determining richness and abundance of midsized to large-bodied mammal species in a highly fragmented Amazonian forest landscape. Twenty-one forest fragments, ranging from 2 to 14,480 ha, and two continuous forest sites were sampled based on sightings, tracks, line-transect censuses, armadillo burrow censuses, and camera trapping. Patch occupancy of 37 species recorded ranged from 4% to all forest sites surveyed. Forest fragment size was the strongest predictor of species persistence, explaining 90% of the variation in species richness. Information-theoretic analysis confirmed that fragment area was the most important explanatory variable for the overall species richness and abundance of mammal species, followed by surface fires, which affected the abundance of seven species. Large mammal species were typically absent from fragments <100 ha, whereas some ubiquitous species were favored by fragmentation, exhibiting hyperabundance in small patches. Our findings highlight the importance of large (>10,000 ha), relatively undisturbed forest patches to maximize persistence and maintain baseline abundances of Neotropical forest mammal species.

Assemblage of medium and large size mammals in an urban Semideciduous Seasonal Forest fragment in Cerrado biome

“…Because of this, it is also common to find the opossum in residential areas. In addition, species like the opossum and small mammals can increase their abundance in small fragments, due to their generalist habits and to the absence of predators (Fonseca & Robinson 1990, Chiarello 1999, Michalski & Peres 2007.…”

“…Species like Tapirus terrestris (Linnaeus, 1758) (tapir), Mazama americana (Erxlesben, 1777) (red brocket), Tayassu pecari (Link, 1795) (white-lipped peccary) e Pecari tajacu (Linnaeus, 1758) (collared peccary) are common to the region (personal observation), but they do not use the fragment, where they must have been extinct due to absence of conditions of utilization, like size and edge effect. The presence of mammals is usually limited by the area size (Chiarello 1999, Michalski & Peres 2007, which is a problem common in urban fragments, because in general the fragments are small. Beyond the area limitation of the fragment, the edge effect may also cause negative effects to the mammalian fauna (Murcia 1995, Stevens & Husband 1998, Fahrig 2003.…”

“…Crooks 2002, Fernández-Juricic 2002, Lacerda et al 2009). The impacts of habitat fragmentation limit the presence of various species in the fragment because they restrict the area of the fragment (Chiarello 1999, Michalski & Peres 2007. They also cause edge effects (Fahrig 2003) in the interaction between the fragment and the matrix (Murcia 1995, Stevens & Husband 1998 and decrease landscape connectivity (Fahrig & Merriam 1994, Sampaio et al 2010.…”

A Survey of mid and large bodied mammals in Núcleo Caraguatatuba, Serra do Mar State Park, Brazil

“…Although standardized line transect surveys provide a powerful dataset for analysis of species abundances they are unlikely to approximate a truly representative sample of the mid and large bodied mammal fauna. This group includes rare, cryptic and illusive species that to achieve management objectives including knowledge of which species are present are best surveyed with a combination of techniques (Michalski & Peres 2007, Espartosa et al 2011, Munari et al 2011. The objective of the present study was to use complementary survey techniques to obtain a baseline species list and estimate the species richness of mid and large bodied mammals in Núcleo Caraguatatuba as the first step to increasing our knowledge of the regional mammalian fauna and to support the management activities within this protected area.…”

Persistência de mamíferos de médio e grande porte em fragmentos de floresta ombrófila mista no estado do Paraná, Brasil

“…Mais espécies ocorrem nos fragmentos maiores, MRT e MRO, e apenas nessas áreas, espécies essas com porte superior a 20 kg, como cateto (Pecari tajacu), capivara (Hydrochoerus hydrochaeris) e veado-mateiro (Mazama americana). A persistência de espécies em fragmentos é explicada, principalmente, pelo tamanho da área remanescente (CHIARELLO, 1999;MICHALSKI;PERES, 2007), mas fatores como o isolamento também podem estar influenciando nas taxas de recolonização e sobrevivência das espécies (CROOKS, 2002). Como MRT e MRO possuem conectividade maior, possivelmente têm maiores taxas de recolonização, o que acaba refletindo positivamente no número de espécies (GILBERT-NORTON et al, 2009).…”