Assessing the relative importance of isolated Ficus trees to insectivorous birds in an Indian human-modified tropical landscape
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The destruction of forest for agricultural expansion has created a vast estate of human-modified land in tropical regions. One group of organisms that are particularly vulnerable to the loss of forest habitat are insectivorous birds. Despite this, few conservation strategies have been identified for this group in human-modified landscapes. We survey the use of 104 isolated trees by insectivorous birds in rural Assam, India. We used an information theoretic model comparison approach to determine the important variables driving insectivorous bird diversity within these isolated trees. Our work demonstrates that the conservation of large trees in human-modified landscapes may play an important role in maintaining bird diversity and ecological function beyond the forest edge. More specifically, we found that isolated Ficus trees hold assemblages with particularly high insectivore abundance, richness and functional diversity when compared to other isolated fruit and large trees. We argue that, where present, Ficus trees should be actively conserved in human-modified landscapes to maintain the composition of insectivore communities in a “Ficus first” strategy.
KeywordsConservation beyond protected areas Birds Ecological function Ficus India Insectivores Isolated trees Multimodel inference
The authors wish to thank Maan Barua, Manju Barua, Barry and Susan Jones, A.J. Tours and Travel, and Wild Grass Eco Lodge for help facilitating this study. Valuable field assistance was provided by Biju Hazarika, Gokul Munda, Soano Rajbonsi, Raju Gogoi, Nakib Ali, Polash Bora, Colia Karmakar, and Humnot Borah. We are very grateful for advice and comments provided by François Rigal, Michael Børregaard, Richard Grenyer, Paul Jepson, Catherine Sheard, Jon Sadler, Ross Crates and an anonymous reviewer.
Compliance with ethical standards
Conflict of interest
The authors have no conflicts of interest to declare.
This research was conducted with ethical approval from the University of Oxford (Departmental CUREC reference number: SOGE C1A-99). Surveys were conducted with permission from local landowners where necessary, and permission to conduct this field work in India was granted by the High Commission of India, London, under visa number 4246496. Field studies did not impact the welfare of the animals studied.
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