Biology subjects

Diengdoh, V. L.

Publications and source records attributed to Diengdoh, V. L..

5 recordsLinked to original sources

bioRxiv2025

Hornbills as drivers of plant range shifts under climate change

Range shifts of plants under climate change depend on frugivore-mediated seed dispersal. However, the role of frugivores in facilitating these shifts remains uncertain. This study assessed how plant-hornbill functional connectivity varied across latitude and elevation in South Asia by integrating species distribution models under present and future climate change scenarios with connectivity analysis under conservative (single-generation) and optimistic (multi-generational) seed dispersal scenarios. The connectivity patterns were synthesised using generalised additive models and indicated that latitude explained significantly more variation in connectivity than elevation. The range shifts of plants were primarily constrained by dispersal limitation rather than by the availability of suitable future habitat. Under conservative dispersal, connectivity remained stagnant despite climate change whereas optimistic dispersal fundamentally reshaped connectivity patterns, creating new pathways that aligned with areas of habitat gain. These findings demonstrate that the capacity of tropical plants to track climate change is critically dependent on hornbills, highlighting the urgent need to conserve both frugivore populations and landscape connectivity to ensure ecosystem resilience.

ecology↗

bioRxiv2024

Impact of land cover and climate change on habitat of Indian birds

Understanding species vulnerability to global change requires approaches that integrate projections of future environmental change with empirical population trends; such integrated assessments remain limited in biodiverse, data-limited tropical regions. In this study, we develop and apply a scalable, decision-oriented framework that synthesises climate and land-cover projections with existing contemporary population data to assess species-level vulnerability and conservation, monitoring, and research priorities for Indian birds. Using an ensemble of machine-learning habitat-suitability models, we projected current and future habitat suitability for 955 species under two 2100 scenarios (SSP3-7.0 and SSP5-8.5). We then integrated these projections with population trends from the State of Indias Birds assessment. We found habitat responses were highly heterogeneous: 507 species were projected to lose suitable habitat under both future scenarios, 327 species were projected to gain habitat, and 121 species exhibited mixed or uncertain responses. The direction and magnitude of projected change varied substantially within and among habitat-specialisation guilds, with overall losses exceeding gains. The synthesis of habitat projections with population trends revealed 121 (mostly wetland) species facing ongoing population decline and future habitat loss, representing high-priority targets for immediate conservation action. A further 300 species, largely forest-associated, were projected to lose habitat but lacked reliable population trend data, highlighting substantial monitoring gaps, while species with mixed or uncertain habitat trajectories emerged as key research priorities. By explicitly integrating projected habitat change, contemporary population trajectories, and data availability, this study advances a transferable framework for prioritising conservation action, monitoring, and research under accelerating global change.

ecology↗

bioRxiv2022

Landscape functional connectivity for butterflies under different scenarios of land-use, land-cover, and climate change in Australia

Pollinating invertebrates are vital to terrestrial ecosystems but are impacted by anthropogenic habitat loss/fragmentation and climate change. Conserving and improving landscape connectivity is important to offset those threats, yet its assessment for invertebrates is lacking. In this study, we evaluated the functional connectivity between protected areas in Australia for 59 butterfly species, under present conditions and different future scenarios (for 2050 and 2090) of land-use, land-cover, and climate change. Using circuit-theory analysis, we found that functional connectivity under present conditions varies widely between species, even when their estimated geographical ranges are similar. Under future scenarios, functional connectivity is predicted to decrease overall, with negative changes worsening from 2050 to 2090, although a few species are positive exceptions. We have made our results available as spatial datasets to allow comparisons with taxa from other studies and can be used to identify priority areas for conservation in terms of establishing ecological corridors or stepping-stone habitat patches. Our study highlights the importance of considering pollinating invertebrates when seeking holistic conservation and restoration of a landscapes functional connectivity, underscoring the need to expand and promote protected areas to facilitate functional connectivity under future scenarios of global change. Research DataThe habitat suitability maps and functional connectivity maps are made available as GeoTiff images via Figshare (10.6084/m9.figshare.19130078).

ecology↗

bioRxiv2021

Predicted the impacts of climate change and extreme-weather events on the future distribution of fruit bats in Australia

AimFruit bats (Megachiroptera) are important pollinators and seed dispersers whose distribution might be affected by climate change and extreme-weather events. We assessed the potential impacts of those changes, particularly more frequent and intense heatwaves, and drought, on the future distribution of fruit bats in Australia. We also focus a case study on Tasmania, the southernmost island state of Australia, which is currently devoid of fruit bats but might serve as a future climate refugium. LocationAustralia (continental-scale study) and Tasmania. MethodsSpecies distribution modelling was used to predict the occurrence of seven species of fruit bats, using an ensemble of machine-learning algorithms. Predictors included extreme-weather events (heatwave and drought), vegetation (as a proxy for habitat) and bioclimatic variables. Predictions were made for the current-day distribution and future (2050 and 2070) scenarios using multiple emission scenarios and global circulation models. ResultsChanges in climate and extreme-weather events are forecasted to impact all fruit-bat species, with the loss and gain of suitable areas being predominantly along the periphery of a species current distribution. A higher emission scenario resulted in a higher loss of areas for Grey-headed flying fox (Pteropus poliocephalus) and Spectacled flying fox (P. conspicillatus) but a higher gain of areas for the Northern blossom bat (Macroglossus minimus). The Grey-headed flying fox (Pteropus poliocephalus) is the only study species predicted to potentially occur in Tasmania under future scenarios. Main conclusionsFruit bats are likely to respond to climate change and extreme weather by migrating to more suitable areas, including regions not historically inhabited by those species such as Tasmania--possibly leading to human-wildlife conflicts. Conservation strategies (e.g., habitat protection) should focus on areas we found to remain suitable under future scenarios, and not be limited by state-political boundaries.

ecology↗

bioRxiv2021

Association between land cover, plant genera and pollinator dynamics in mixed-use landscapes

Pollinators are globally threatened by land-use change, but its effect varies depending on the taxa and the intensity of habitat degradation. However, pollinator-landscape studies typically focus on regions of intensive human activities and on a few focal species. Evaluating pollinator responses in landscapes with moderate land-use changes and on multiple pollinator groups would therefore fill an important knowledge gap. This study aims to determine the predictive capacity and effect of habitat characteristics on the relative abundance of multiple pollinator groups in mixed-use landscapes. To do this, we collected field data on the relative abundance of nectivorous birds, bees, beetles, and butterflies across the Tasman Peninsula (Tasmania, Australia). We then applied Random Forests to resolve the effects of land use (protected areas, plantation, and pasture), land cover at different radii (100 m and 2000 m), and plant genera on pollinator abundance. Overall, land cover and plant genera were more important predictors of pollinator abundance than land use. And the effect of land use, land cover, and plant genera varied depending on the pollinating group. Pollinator groups were associated with a range of plant genera, with the native genera Acacia, Leptospermum, Leucopogon, Melaleuca, Pomaderris, and Pultenaea being among the most important predictors. Our results highlight that one size does not fit all--that is pollinator response to different landscape characteristics vary, emphasise the importance of considering multiple habitat factors to manage and support a dynamic pollinator community, and demonstrates how land management can be informed using predictive modelling.

ecology↗