Oil palm monoculture induces drastic erosion of an Amazonian forest mammal fauna

Abstract

Oil palm monoculture comprises one of the most financially attractive land-use options in tropical forests, but cropland suitability overlaps the distribution of many highly threatened vertebrate species. We investigated how forest mammals respond to a landscape mosaic, including mature oil palm plantations and primary forest patches in Eastern Amazonia. Using both line-transect censuses (LTC) and camera-trapping (CT), we quantified the general patterns of mammal community structure and attempted to identify both species life-history traits and the environmental and spatial covariates that govern species intolerance to oil palm monoculture. Considering mammal species richness, abundance, and species composition, oil palm plantations were consistently depauperate compared to the adjacent primary forest, but responses differed between functional groups. The degree of forest habitat dependency was a leading trait, determining compositional dissimilarities across habitats. Considering both the LTC and CT data, distance from the forest-plantation interface had a significant effect on mammal assemblages within each habitat type. Approximately 87% of all species detected within oil palm were never farther than 1300 m from the forest edge. Our study clearly reinforces the notion that conventional oil palm plantations are extremely hostile to native tropical forest biodiversity, which does not bode well given prospects for oil palm expansion in both aging and new Amazonian deforestation frontiers.

Mammal Diversity in Oil Palm Plantations and Forest Fragments in a Highly Modified Landscape in Southern Mexico

“…In Brazil there was also very little overlap in the structure of the mammal communities between oil palm plantations and native forest, but this was in part due to the presence of arboreal species in the forest, which we were unable to census in this study (Mendes-Oliveira et al, 2017). Further, in the Brazilian study, 87% of all mammals found in oil palm were never farther than 1.3 km from the forest edge (Mendes-Oliveira et al, 2017). Given that the oil palm plantations in our study were <100 ha, we probably observed some mammal species using the plantations that would not be found in the core of larger plantations.…”

“…Our results differ somewhat from other studies of oil palm impacts on mammal communities in Latin America, mostly likely due to the differences in plantation sizes. In both Colombia and Brazil, where oil palm plantations are large (>100 ha), species richness and composition of mammals was significantly reduced in oil palm plantations compared to native forests (Mendes-Oliveira et al, 2017;Pardo et al, 2018a). In terms of mammal community structure, in Colombia the riparian fragments had species compositions that were more similar to one another than the oil palm plantations, and there was little overlap in the structure of the two communities (Pardo et al, 2018a).…”

“…Some authors have suggested that conversion to oil palm may be among the major drivers of the next wave of habitat change in the Neotropical lowlands (Gutiérrez-Vélez and DeFries, 2013; Lees and Vieira, 2013). While the majority of studies on the impacts of oil palm plantations on biodiversity have taken place in Southeast Asia, recent work in Latin America shows similar patterns to those found in Asia in terms of major reductions in bird, mammal, amphibian and invertebrate species in oil palm compared to native forest (Gallmetzer and Schulze, 2015;Lees et al, 2015;Juen et al, 2016;Mendes-Oliveira et al, 2017;Pardo et al, 2018a). Further, oil palm plantations appear to be a barrier to movement for some species of forest birds, bats, and bees (Freudmann et al, 2015;Knowlton et al, 2017;Brito et al, 2018).…”

“…The impacts of oil palm plantations on biodiversity in Latin America have mostly been studied in large-scale (>100 ha) plantations in the South American countries of Brazil (e.g., Lees et al, 2015;Mendes-Oliveira et al, 2017) and Colombia (e.g., Pardo et al, 2018a), while none to our knowledge have examined the smaller-scale expansion of oil palm in Mexico.…”

“…Mammals play important roles in food webs and provide many ecosystem services, including seed dispersal, pollination, predation, and decomposition (Pardo et al, 2018a). Only a few studies have examined the impact of oil palm plantations on mammals in Latin America (Mendes-Oliveira et al, 2017;Pardo et al, 2018a), and none to our knowledge has taken place in small-scale plantations or anywhere in Mexico. In this study, we used a camera trapping survey to examine how terrestrial mid to large-bodied mammals respond to a highly modified landscape mosaic in the southeastern lowlands of Tabasco, Mexico, including small (<100 ha) oil palm plantations and secondary forest fragments.…”