Biology subjects

Munda, B.

Publications and source records attributed to Munda, B..

3 recordsLinked to original sources

bioRxiv2023

Bird communities in a selectively logged tropical montane forest are dominated by small, low-elevation species

Tropical montane forests are critical centres of terrestrial biodiversity and endemism, and face a range of threats, including selective logging and climate change. However, few studies have explored the joint influence of these threats, particularly in tropical mountains, despite how crucial it is to understand the cumulative impact of forest loss and climate change on biodiversity. We used mist-netting and bird ringing data from a long-term (10-year) community and population monitoring program to examine how the composition of the mid-elevation Eastern Himalayan understorey bird community changed in the mid-elevation primary and logged forest. Because logged forest is warmer than primary forest, we hypothesised that the bird community would shift towards lower elevation species, with a faster transition in logged forest. Further, because logged forest has lower arthropod abundance, we hypothesised that the primary forest community would have larger species than the logged forest community. Our study shows that the bird community in the logged forest shifted towards lower-elevation species than in the primary forest (although this was not statistically significant). Moreover, we found that smaller species were better able to colonise warmer logged forest, whereas larger species reached higher densities in primary forest. These trends are likely to be driven by climate change causing upslope range shifts and logged forest selecting for species that are likely to tolerate the consequently altered abiotic (higher temperatures) and biotic (lower resources) environment. These findings have significant implications for understanding the impacts of forest loss and climate change on biodiversity, particularly in tropical montane forests.

ecology↗

bioRxiv2023

Understanding inter-individual social networks in mixed-species bird flocks

Mixed-species flocks (MSFs) are an important form of social organisation in forest bird communities worldwide. MSFs provide participants with the benefits of reduced predation risk and/or enhanced foraging efficiency. Recent work has shown that participation in MSFs confers long-term survival benefits in the face of anthropogenic change. However, our understanding of MSFs mainly comes from studies that examine species-level networks, where each node is a unique species and the edges or connections between nodes are associations/interactions between species. While valuable, such approaches might not allow us to understand and investigate the mechanisms that drive MSF formation and structure because social interactions and their effects occur at the individual-level. Empirical studies on multi-species, individual-level MSF social networks have seldom been undertaken due to the various complexities and logistical challenges involved. In this study, we use mist-netting and colour-ringing followed by a standardised observation protocol to construct individual-level social networks in MSFs at 2000m ASL in Eaglenest Wildlife Sanctuary, Arunachal Pradesh, Eastern Himalaya, India. First, we found two separate flocktypes at our study site, comprising two distinct sets of understorey species. The mechanisms contributing to individual-level co-occurrences are likely to differ between these flocktypes, and with MSFs in the Neotropics. The Rusty-fronted Barwing (the nuclear species of one flocktype) shows spatially disjunct territories for each flock while the Yellow-throated Fulvetta (nuclear species of the other flocktype) shows large spatial overlap in its MSF networks, which is likely driven by non-individual-specific benefits such as predation risk dilution. Further, the addition of associating individuals to the social networks has opposite impacts on the two networks. The addition of Coral-billed Scimitar Babblers to the barwing networks greatly reduces network modularity because the associating individuals bridge two modules of barwings (both spatially and in the social network). On the contrary, territorial Rufous-capped Babblers and Grey-cheeked Warblers increase the modularity of the spatially overlapping fulvetta network. Our study provides novel insights into flock formation mechanisms in the Eastern Himalaya, likely applicable to other multi-species flock systems in the Old World.

ecology↗

bioRxiv2022

The effect of selective logging on microclimates, arthropod abundance and the foraging behaviour of Eastern Himalayan birds

1. Selective logging--the practice of removing a subset of commercially important trees from a forest--is a globally pervasive form of forest degradation. Selective logging alters both the structure and function of forests and the composition of ecological communities. 2. Tropical insectivorous birds are highly vulnerable to microhabitat alterations in logged forest. Such altered microhabitats might affect the foraging of forest birds by altering (a) resource availability, and (b) foraging behaviour. 3. We investigated the effect of selective logging on microclimates, prey availability, foraging behaviour and the foraging success of eastern Himalayan birds in the breeding season. 4. Selective logging alters temperature-humidity microclimates and the composition of arthropod communities, both of which are likely to then collectively alter foraging behaviour by birds. We show that birds spent a lower proportion of their time foraging in primary compared with logged forest. Further, selective logging interacts with species traits such as body mass, preferred foraging stratum (understorey, midstorey or canopy) and foraging manoeuvre to influence foraging success. Gleaners generally foraged more successfully in primary forest and salliers in logged forest, although these patterns were modified by body mass and foraging stratum. 5. Synthesis and applications: Our study shows how altered microclimates in anthropogenically modified habitats can influence resource availability and have downstream impacts on the behaviour of species at higher trophic levels.

ecology↗