Conservation value and permeability of neotropical oil palm landscapes for orchid bees.

George Livingston,Shalene Jha,Andres Vega,Lawrence Gilbert,Brock Fenton

doi:10.1371/journal.pone.0078523

Abstract

The proliferation of oil palm plantations has led to dramatic changes in tropical landscapes across the globe. However, relatively little is known about the effects of oil palm expansion on biodiversity, especially in key ecosystem-service providing organisms like pollinators. Rapid land use change is exacerbated by limited knowledge of the mechanisms causing biodiversity decline in the tropics, particularly those involving landscape features. We examined these mechanisms by undertaking a survey of orchid bees, a well-known group of Neotropical pollinators, across forest and oil palm plantations in Costa Rica. We used chemical baits to survey the community in four regions: continuous forest sites, oil palm sites immediately adjacent to forest, oil palm sites 2km from forest, and oil palm sites greater than 5km from forest. We found that although orchid bees are present in all environments, orchid bee communities diverged across the gradient, and community richness, abundance, and similarity to forest declined as distance from forest increased. In addition, mean phylogenetic distance of the orchid bee community declined and was more clustered in oil palm. Community traits also differed with individuals in oil palm having shorter average tongue length and larger average geographic range size than those in the forest. Our results indicate two key features about Neotropical landscapes that contain oil palm: 1) oil palm is selectively permeable to orchid bees and 2) orchid bee communities in oil palm have distinct phylogenetic and trait structure compared to communities in forest. These results suggest that conservation and management efforts in oil palm-cultivating regions should focus on landscape features.

Highlights

The greatest threat to terrestrial biodiversity is land-use change [1]
The plantation regions were similar in environmental conditions, oil palm was hotter and drier than forest, and no orchids were observed in oil palm (Table 1, [16])
In this study we show that orchid bee communities are sensitive to oil palm habitat and increasing isolation from forest habitat

Summary

Introduction

Among drivers of land-use change, the most important is the expansion and intensification of agricultural land [2]. The majority of global agricultural expansion has occurred in tropical regions [3]. The expansion of international commodity agriculture (e.g., coffee [4], soybeans and oil palm [5]) in the tropics presents a major global conservation and sustainability challenge [6]. Oil palm (Elaeis spp.) is among the most important of these commodity crops in the wet tropics, covering 14.5 million hectares globally [7] and rapidly expanding due to demand as a key biofuel feedstock [8,9]. Documenting and explaining patterns of biodiversity loss are a key first step towards developing more sustainable agricultural production [5]

Methods

Results

Conclusion