Recovery of indigenous butterfly community followi

Authors: F B Vincent Florens John R Mauremootoo Simon V Fowler Linton Winder Cláudia Baider

Publish Date: 2010/11/04

Volume: 19, Issue: 14, Pages: 3835-3848

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Abstract

Invasive alien species pose one of the highest threats to biodiversity especially in isolated oceanic islands where high rates of both endemism and extinction risk also usually prevail Few studies have investigated the impact of invasive alien plants on butterflies in insular ecosystems despite butterflies representing a key indicator group for terrestrial arthropod diversity Using the Pollard Technique we quantified butterfly species richness and abundance in eight wet lowland forest areas invaded by alien plants principally the strawberry guava Psidium cattleianum Sabine on the tropical volcanic island of Mauritius and compared the results with paired adjacent forest plots that had been weeded of alien plants between 2 and 12 years previously Butterfly assemblages in weedinfested and weeded forests were distinctly different with higher species richness and much higher butterfly abundance in the latter At least some of these differences seemed attributable to weed removal effects on forest structure but understanding the precise mechanisms involved will require further study The results suggest that alien plant invasion may have contributed to the extinction of certain endemic taxa and can increase the likelihood of butterfly species extinction by reducing population sizes through reduced habitat quality Such a shift in a forest’s butterfly assemblage is likely to have negative effects on both their indigenous predators and the plants they pollinate It is argued that in order to maintain butterfly and other arthropod diversity and function in these forests alien plant control must be maintained and extended beyond the current 1 of surviving forest remnantsWe thank the National Parks and Conservation Service of Mauritius for giving access to study sites and Malika Virah Sawmy JeanClaude Sevathian and John Williams for varied assistance Clare TownerMauremootoo helped in the field Jon Sullivan Dominique Strasberg JeanYves Meyer Steven Goodman PierreMichel Forget and two anonymous reviewers provided useful comments to improve this paper A British Ecological Society’s Overseas Bursary awarded to the first author enabled the survey of plant communities

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