Representative image of an ant
Credit: iStock Photo
Bengaluru: The presence of a genus of insect-eating ants is shaping the diversity of bird species in mid-elevation mountainous regions, a new study by Indian Institute of Science (IISc) researchers has found.
Oecophylla ants, known for their aggressive and dominant behaviour, are voracious predators of insects at the bases of mountains found in the paleotropics, covering Africa, Asia and Oceania. Researchers at the Centre for Ecological Sciences (CES), led by Umesh Srinivasan, Assistant Professor, tested how the ants’ presence affected the diversity of insect-eating birds, especially at lower elevations.
The study was published in Ecology Letters. The researchers, using existing information about bird species in different mountain ranges, categorised the birds under dietary groups (like insectivores and omnivores), and monitored species in each group at different elevations, for every 100 metres.
Nectar and fruit-eating birds that weren’t competing with Oecophylla ants reduced in species diversity as the elevation increased. The researchers estimated that Oecophylla ants competing with insect-eating birds for food at lower elevations could have pushed these birds higher up in the mountains; the diversity was highest at about 960 metres.
Kartik Shanker, Professor at CES and co-author, noted that studies on mountain species diversity, traditionally, do not focus on competition among the species.
IISc noted that mountains, home to 85 per cent of the world’s amphibians, bird, and mammalian species, are a highly diverse ecosystem and integral to conservation efforts.
If climate change pushes the ants’ ranges higher, bird species at higher elevations will also be impacted, Srinivasan said.