Community structure and diversity of tropical forest mammals: data from a global camera trap network

Abstract

Terrestrial mammals are a key component of tropical forest communities as indicators of ecosystem health and providers of important ecosystem services. However, there is little quantitative information about how they change with local, regional and global threats. In this paper, the first standardized pantropical forest terrestrial mammal community study, we examine several aspects of terrestrial mammal species and community diversity (species richness, species diversity, evenness, dominance, functional diversity and community structure) at seven sites around the globe using a single standardized camera trapping methodology approach. The sites-located in Uganda, Tanzania, Indonesia, Lao PDR, Suriname, Brazil and Costa Rica-are surrounded by different landscape configurations, from continuous forests to highly fragmented forests. We obtained more than 51 000 images and detected 105 species of mammals with a total sampling effort of 12 687 camera trap days. We find that mammal communities from highly fragmented sites have lower species richness, species diversity, functional diversity and higher dominance when compared with sites in partially fragmented and continuous forest. We emphasize the importance of standardized camera trapping approaches for obtaining baselines for monitoring forest mammal communities so as to adequately understand the effect of global, regional and local threats and appropriately inform conservation actions.

Figure 1.

Map of a typical TEAM camera trap array at the Central Suriname Nature Reserve, Suriname. Each point represents a camera trap location. Camera traps are placed at a density of one camera trap every 2 km² and distributed in two sampling arrays of 30 camera traps each (North and South of the Coppename River).

Figure 2.

Species accumulation curves for the seven sites using the exact method described in Colwell et al. [28]. The vertical line is the cut-off point used to estimate species richness for all sites. CSN, Central Suriname Nature Reserve, Suriname; UDZ, Udzungwa, Tanzania; BBS, Bukit Barisan, Indonesia; MAS, Manaus, Brazil; BIF, Bwindi, Uganda; VB, Volcan Barva, Costa Rica; NAK, Nam Kading, Lao PDR. Solid line, continuous forest; dashed lines, partially fragmented forest; dotted lines, highly fragmented forest.

Figure 3.

Relationship between surrounding landscape structure at a site (estimated as the size of the protected area enclosing the camera trap array) and measures of community diversity. (a) Species richness (from figure 2 at cut-off sampling intensity), (b) Shannon diversity (H), (c) evenness (EH), (d) dominance (Berger–Parker D), (e) functional diversity (FDis, functional dispersion). Site abbreviations are shown next to each point (see caption of figure 2). Broken lines are least-square regression models.

Figure 4.

Forest mammal community structure for all seven sites. Sites are arranged by continent (rows) and surrounding landscape structure (columns). Individual figures show the distribution of species along two functional traits: body size (expressed in a log scale) and trophic category. Each circle in the figure represents a species in functional space, with the size of the circle proportional to the estimated occupancy.