Study highlights importance of last patches of tropical lowland forest in Assam

Forest fragments protect key interactions between plants and fruit-eating birds, thus maintaining biodiversity in fragmented landscapes

By DTE Staff
Published: Friday 23 July 2021
Oriental Pied Hornbill feeding on Ficus altissima. Photo: Abir Jain
Oriental Pied Hornbill feeding on Ficus altissima. Photo: Abir Jain Oriental Pied Hornbill feeding on Ficus altissima. Photo: Abir Jain

A recent study by researchers has highlighted the importance of the last fragments of tropical lowland forests in Assam by showing interactions between plants and fruit-eating birds in them.  

The researchers belonged to the Wildlife Institute of India (WII) in Dehradun and the Nature Conservation Foundation non-profit in Bengaluru. 

They showed that small fruit eaters such as bulbuls and barbets “fed upon the highest number of fruits” in both, fragmented and contiguous forests. They were crucial in seed dispersal in both these types of forests.

They also found that the remaining patches of forest were very important for birds like the White-throated Brown Hornbill, which dispersed larger seeds that other birds were not able to.

The researchers cited these examples to show that such forest segments help to connect bigger portions of forest and thus help in the flow of biodiversity in them. They called for legal protection of such forest patches.

The authors collected field data by observing the feeding activity of frugivorous birds inside the forests and documented the diversity of fruit species they fed upon. 

They conducted sampling in two forest fragments experiencing degradation pressures namely Doom Dooma Reserve Forest and Kakojan Reserve Forest and a less disturbed, better protected contiguous forest patch, Dehing Patkai National Park. All three are located in Upper Assam.

The researchers found that fragmentation of habitats had resulted in reduced interactions between plants and frugivorous birds in forest patches. However, despite this, fragmented forest patches continued to harbour interactions and distinct ones at that, between frugivorous birds and plants.

The scientists documented 238 interactions between 63 fruiting plant and 44 frugivorous bird species across all sites.

They found that forest fragments had a higher prevalence of species associated with open habitats and fewer large-seeded plant species, dependent on large birds for seed dispersal.

The study was published June 26, 2021 in the journal Biotropica. The authors have claimed that it is among the first studies from the Asian tropics to study the impact of forest fragmentation on plants and frugivorous birds.

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