COS 240-3 - CANCELLED - What are the specific ecological settings in a modified landscape that permit return of faunal biodiversity?

Abstract: Invasive landscapes negatively impact the richness and abundance of native biodiversity. On the other hand, studies also show their potential for native faunal colonisation. Given the rapid depletion of natural forests, it becomes a prerogative to look for the conservational aspects of such landscapes. Our study examines the ecological settings within invasive habitats that permit the establishment of forest faunal species. We also use the faunal functional traits to assess the different types of stands and their respective colonising faunal guilds.

Birds are a helpful taxon to assess the impacts of invasive landscapes, as their ecology and distribution are relatively well-studied. Few studies have studied the positive effects of invasive plant species on bird distribution, particularly habitat-specialist species. Our research focuses on birds of tropical montane forests.

The heavily modified landscape of Western Ghats sky-islands provides us with an excellent system to study this phenomenon. Timber management has created a complex wooded landscape of Shola forests and plantations of Acacia, Eucalyptus and Pine, with varying intensity of understory of regenerating forest trees and invasive acacia and pine. Several threatened endemic, understorey birds inhabit these novel invasive woodland habitats. The reasons and drivers of colonisation are, however, unclear.

This study assesses the impact of the structural and landscape characteristics associated with the invaded habitats on avian colonisation. We also looked at the difference in the variety of trophic and locomotory traits of birds due to the compositional attributes of the overstory.

We conducted sampling of birds and vegetation in 0.5% of the largest Shola Sky Islands ( >1400m MSL) of Anamalai-Palani hills and Nilgiri hills gridded into nested cells of area 1ha and 4ha. We used playback of target species in four temporal replicates to record their presences. Presence of other birds were also noted. We also quantified vegetation and landscape variables.

We surveyed 250 cells and found that understory structure, canopy-cover and altitude determine the presence of most study species. Our results also suggest that biodiversity services supplied by birds are more effectively restored in specific invasive stands (i.e. Eucalyptus stands) than in others (Acacia and Pine stands).

This study indicates that a novel habitat of exotic timber plants can form suitable habitats for endemic, endangered, understorey birds when the overstory composition and vegetation structure are appropriate. Such succession will promote connectivity and gene flow across hitherto unconnected habitat islands and have major consequences for conservation.