Biology subjects

Shukla, U.

Publications and source records attributed to Shukla, U..

2 recordsLinked to original sources

bioRxiv2024

Patterns of leaf, flower and fruit phenology and environmental relationships in a seasonal tropical forest in the Indian Eastern Himalaya

Tree phenology plays an important role in determining the structure and function of tropical forest communities. However, there are few long-term studies on tree phenology from South Asia. We monitored 716 trees of 54 species monthly from 2011 to 2023 for leaf flush, flowering, and fruiting in Pakke Tiger Reserve, Arunachal Pradesh, India. We examined monthly patterns in the percentage of species and trees in leaf flush, flower and fruit and characterized phenological seasonality using circular statistics. Flowering periodicity was classified using Fourier analysis and we examined the relationships between phenological activity and temperature, rainfall, solar radiation and daylength using GAMLSS. Leaf flush and flowering were moderately seasonal, peaking in the warm dry season months of March to May. Fruiting patterns and their seasonality differed among dispersal modes. At the community level and for bird-dispersed species, fruiting was bimodal and relatively aseasonal, peaking in April and October. The highly seasonal fruiting of mammal-dispersed species peaked in October, while that of mechanically-dispersed species was bimodal and concentrated in the dry season months. The majority of species (78.13%) and trees (51.17%) flowered annually. Daylength, solar radiation and minimum temperature had significant nonlinear effects on phenology. This indicated the existence of narrow ranges of optimal climatic conditions for phenology, which could be affected by climate change. Our study emphasizes the need for long-term monitoring to rigorously quantify phenological patterns, particularly in the context of rapid global change.

plant biology↗

bioRxiv2020

Patterns of roost site use by Asian hornbills and implications for seed dispersal

Animals spend a significant amount of time roosting. Therefore, understanding roosting patterns and the processes that influence roosting behaviour and roost site choice is essential. Hornbills exhibit interesting roosting patterns with some species roosting communally in large flocks. They are important seed dispersers and patterns of roost site use can have a significant influence on seed dispersal distributions and thereby on plant recruitment. We documented roost site use by four Great Hornbills (Buceros bicornis) and one Wreathed Hornbill (Rhyticeros undulatus) at a site in north-east India using GPS telemetry. We examined the influence of riverine habitats, nests and foraging range on roost selection. We determined the proportion of seeds that hornbills disperse at roosts and the dispersal distances of seeds dispersed at roosts from the source trees. Through telemetry, we found that roosts of Great Hornbills were generally in forested habitats. Our telemetry data showed that Wreathed Hornbill roosts were close to the river. These results were corroborated by observational data from roost sites where we had regular detections of relatively large flocks of Wreathed Hornbills and occasionally Great Hornbills. The roost sites were not close to the nest sites and were generally within the 95% kernel density diurnal activity ranges. Hornbills dispersed a small proportion of seeds at roost sites. Seeds dispersed at roost sites had almost twice the dispersal distances compared to those dispersed at non-roost sites. This study highlights variation in roost site pattern across individual hornbills and its implications for seed dispersal.

ecology↗