The health of a forest is dependent on the bird and animal species that reside in it. The symbiotic relationship the flora and fauna share is crucial in both their survival. But can isolated pockets of small forests, under constant human encroachment, attract diverse bird species? It seems like size doesn’t matter. Although many of these fragmented forests, which were once part of a larger forest range, are under degradation stress, these still have an ecosystem for birds to breed in, at least for now, states a new study.
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With a focus on lowland forest pockets, found only in Assam, the study looked at the interaction and impact on plants and fruit-eating birds in fragmented, small forests and large, expansive forests. The four-month study was carried out in three areas two small reserve forests - Doom Dooma Reserve Forest and Kakojan Reserve Forest (both ~25 km2) – and a better protected larger forest Dehing Patkai National Park (>100 km2) in upper Assam. The two reserve forests are part of the 25 such fragmented, standalone reserve forests in the region, which are facing resource exploitation. Interestingly, these are the only surviving lowland rainforests in the country.
The study, which was published in journal Biotropica, was conducted by researchers from the Wildlife Institute of India (WII, Dehradun) and the Nature Conservation Foundation (NCF, Bangalore).
The researchers observed the feeding activity of fruit-eating or frugivorous birds – small and big – in these three forests, and the kind of fruiting plants they preferred to eat. About 44 birds were recorded feeding on 63 species of fruiting plants, although the researchers observed 180 bird species. “This study looked at the differences in the plant and frugivorous bird communities between forest fragments and contiguous forest. We found that the fragments (small reserve forests) harbour diverse sets of interactions,” said Abir Jain, the lead co author of the study, and researcher at WII.
Some of the bird species observed includes Blue-winged Leafbirds, Thick-billed Green Pigeon, Blue-throated Barbets, among others. Most birds that fed on fruits were small-sized birds, underscoring their importance in maintaining the propagation of plant species.
About 90 per cent of tropical forest plants are dependent on animals and birds, who consume its fruits. Interestingly, in some of these fragmented forests, fast growing shrubs, climbers and fig trees, are being observed. Researchers believe it’s due to the absence of extensive tree canopy. These fruiting climbers and trees, in turn, have become important food sources, especially in these small forest areas.
“Different species and individuals of figs fruit at different times of the year and serve as a vital source of food all year round including the lean season. This underscores the importance of figs and the need to conserve them,” explains co-author Dr Navendu Page, a plant ecologist from WII.
It’s not just small birds, even big birds, which usually breed in the dense larger forests, were seen spotted in these fragmented forests. For instance, the endangered White-throated Brown Hornbill were found breeding in these fragmented forest reserves, and are essential in dispersing seeds of large-seeded plants.
“The range of Brown Hornbill is shrinking in north-east India due to habitat loss and hunting. Conserving these remnant forest patches for the conservation of these birds is vital,” says Dr Rohit Naniwadekar from NCF, another co-author of the paper.
The study concluded that although these forest reserves may occupy smaller land area as compared to larger forests, they are valuable in providing refuge to wide array of bird species, which in turn help the indigenous fruiting plant species. “Administering improved protection and active ecological restoration by planting native fruiting plants in degraded fragments with the support of local communities must be carried out to preserve these fragments and the biodiversity they represent,” suggests Dr GS Rawat, co author and former dean and scientist from WII.
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