Seasonal Changes in Bird Species and Feeding Guilds along Elevational Gradients of the Central Himalayas, Nepal

Abstract

The Himalayas are a global hotspot for bird diversity with a large number of threatened species, but little is known about seasonal changes in bird communities along elevational gradients in this region. We studied the seasonality of bird diversity in six valleys of the Central Himalayas, Nepal. Using 318 plots with a 50 m radius, located from 2200 to 3800 m a.s.l., and repeated sampling during different seasons (mainly pre-monsoon, monsoon, and post-monsoon), we analyzed 3642 occurrences of 178 species. Birds classified in the literature as resident were more species-rich than migratory birds (140 vs. 38 species). In all six valleys and within the studied elevation range, species richness of all birds showed a peak at mid-elevation levels of 2600 or 3000 m a.s.l. Similar patterns were found for the most species-rich feeding guilds of insectivores (96 species) and omnivores (24 species), whereas the species richness of herbivores (37 species including frugivores) increased towards higher elevations. Among these feeding guilds, only species richness of insectivores showed pronounced seasonal changes with higher species numbers during post-monsoon season. Similarly, individual bird species showed distinct spatio-temporal distribution patterns, with transitions from species dominated by elevational differences to those characterized by strong seasonal changes. In an era of climate change, the results demonstrate that individual bird species as well as feeding guilds might greatly differ in their responses to climate warming and changes in the seasonality of the precipitation regime, two aspects of climate change which should not be analyzed independently.

Correlates of avifaunal diversity along the elevational gradient of Mardi Himal in Annapurna Conservation Area, Central Nepal

“…From the point-count survey of two seasons (summer and winter), we recorded a total of 112 species of birds belonging to 13 orders and 35 families. We observed that insectivorous form is the most species-rich feeding guild in the Mardi Himal, which is consistent to many other studies in birds (Herzog et al 2005;De Bonilla et al 2012;Katuwal et al 2016). About 29% (32/112) of the bird species observed in Mardi Himal are migratory birds which is almost similar to the observation of Neupane et al (2020) along the Kaligandaki River basin of the ACA but lesser proportion than that of the overall contribution of migrants (38%, 336/884) (Grimmett et al 2016) in the avian diversity of Nepal.…”

“…2009; Voskamp et al 2017;Somveille et al 2018) as well as local spatial scales (Ruggiero and Hawkins 2008;Wu et al 2013;Katuwal et al 2016;Pan et al 2016). Avian species richness along the elevational gradient has been found to display four distinct patterns: decreasing richness, low-elevation plateaus, low-elevation plateaus with mid-peaks and mid-elevational peaks (McCain 2009).…”

Nonlinear Regression Applications in Modeling Over-Dispersion of Bird Populations

“…As previously well-documented, seasonality (Caula et al, 2008;Chen et al, 2019;Gomes et al, 2017;Girma et al, 2017;Katuwal et al, 2016) and habitat (Caula et al, 2008;Chen et al, 2018;Chen et al, 2019;Durmuş et al, 2018;Girma et al, 2017) influence the species richness and population size. The present results of the study are consistent with the previous reports given above.…”

Modelling the responses of Australian subtropical rainforest birds to changes in environmental conditions along elevational gradients

“…; Katuwal et al . ), we obtained information from the Handbook of Australian, New Zealand and Antarctic Birds (HANZAB) (Marchant & Higgins , ; Higgins & Davies ; Higgins ; Higgins et al . , ; Higgins & Peter ) on feeding guild and body size for each bird species.…”

“…; Katuwal et al . ). Associating species traits and environmental variables using species abundance data is a challenge in multivariate ecological analysis known as the fourth‐corner problem.…”