Habitat quality and edge area of fragments determine insect diversity in a heavily used landscape: Implications for forest landscape restoration

Abstract

AbstractWorldwide, forest fragmentation and degradation have affected the flora and fauna, and are threatening the livelihood of people depending upon forest resources. It is essential to understand the underlying ecological processes to better manage such landscapes. In ecological assessments, insects are useful tools to assess the effects of human interventions such as restoration, as insects are vital for several ecosystem processes. Therefore, we studied the ecological processes that determined the distributions of the epigeic insect communities among the degraded forest fragments of the Attappady Hills (Western Ghats, India), which are being restored. Our objectives were to determine the spatial variations in the epigeic insect communities and their responses to habitat quantity and quality of the forest fragments, along with an assessment of the invasive ants’ responses to fragmentation and degradation, and their effects on the native insect communities. We used pitfall traps in several forest fragments representing varying disturbance levels along an east–west gradient. The diversity of various insect taxonomic groups and functional feeding guilds were higher in smaller fragments than compared to larger fragments due to edge effects. The variations in the distributions of insect communities were explained by the habitat features that were spatially correlated. Invasive ants, Anoplolepis gracilipes, infested the smaller fragments where the vegetation quality had degraded. We conclude that an understanding of the effects of fragmentation and degradation on insect communities is vital to restoration managers as ecological restoration becomes an important strategy to reverse degradation and to revive ecological processes of fragmented forests.Abstract in Malayalam is available with online material.