Birds in the Himalayas: What drives beta diversity patterns along an elevational gradient?

Abstract

Beta diversity patterns along elevational gradients have become a hot topic in the study of biogeography and can help illuminate the processes structuring mountain ecosystems. Although elevational species richness patterns have been well documented, there remains much uncertainty over the causes of beta diversity patterns across elevational gradients. We conducted bird surveys and obtained high‐resolution climatic data along an elevational gradient in Gyirong Valley in the central Himalayas, China, between 1,800 and 5,400 m elevation. In total, we recorded 182 bird species (including 169 breeding birds). We simulated beta diversity patterns with the mid‐domain effect (MDE) null model and conducted distance‐based redundancy analyses (db‐RDA) to relate beta diversity to dispersal limitations, spatial constraints, habitat complexity, contemporary climate, and historical climate. Mantel tests and variation partitioning were employed to identify the magnitude of independent statistical associations of environmental factors with beta diversity. Patterns of empirical and simulated beta diversity were both hump‐shaped, peaking at intermediate elevations. The db‐RDA indicated that beta diversity was correlated with changes in spatially structured environmental factors, especially with contemporary climate and habitat complexity. Mantel tests and variation partitioning also suggested that climate dissimilarity was the major independent correlate of beta diversity. The random community structure and spatial constraints may also contribute to the overall hump‐shaped pattern. Beta diversity of bird communities in Gyirong Valley could be explained by the combination of different factors but is mainly shaped by the spatially structured environmental factors, especially contemporary climate.

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

“…These results are in line with previous studies for birds in the Himalaya (McCain 2009;Acharya et al 2011b;Paudel and Šipoš 2014;Katuwal et al 2016;Hu et al 2018) exhibiting a hump-shaped pattern. The avian richness in Mardi Himal peaked at around 1900 m asl, much similar to the study in the eastern Himalaya (2000 m) (Acharya et al 2011b) but lower than that of other mountains in the central Himalaya (2600-3000 m asl) (Katuwal et al 2016), generalized analysis to the entire Nepal Himalaya (2800 m asl) (Paudel and Šipoš 2014) and Gyirong Valley in China (2400-3000 m asl) (Hu et al 2018). Richness pattern similar to that of the wet eastern Himalaya might be associated to the high annual precipitation received at the mid-elevations of Mardi Himal lying on the windward side of the Annapurna Himalayan range proximal to the Pokhara valley, the highest precipitating area of Nepal.…”

“…The lowest species richness of birds above 2500 m asl might be attributed to lesser area, Fig. 6 Relationship between bird richness and different factors (mean precipitation, distance to the nearest water source and distance to the nearest settlement) in a summer season and b winter season in Mardi Himal trekking route, ACA minimum precipitation, harsh climatic conditions, lesser productivity and resource limitations are the major drivers of lower species richness at the peaks of mountain ranges (Acharya et al 2011b;Hu et al 2018). BCN 2011described lesser species richness in meadows of the central Himalaya that is associated with overgrazing and less availability of food.…”

“…Extreme shifts in temperature drive the long-distance or trans-continental migration in birds, whereas, fluctuation in the precipitation often causes altitudinal migration within a region (He et al 2019). Some birds, especially the insectivores, are the habitat specialists and are least dispersive or residential (Zhang et al 2009;Hu et al 2018;He et al 2019). Therefore, considering the nutritional guild is important while exploring the drivers of seasonal diversity pattern in avian communities.…”

Avian richness of the Basanta Protected Forest, far-western lowland Nepal: Implication for conservation

“…We observed that insectivorous form is the most speciesrich feeding guild in the Basanta forest, which is consistent with many other studies in birds (Katuwal et al 2016. Highly diverse avian community of the study area might be due to greater habitat complexity (Pan et al 2016, Hu et al 2018. Lakes complex, riverine habitat, forest habitat with different forest types like chir-pine forest, chir-pine broad-leaved forest, Hill sal forest, and tropical sal and mixed broadleaved forest have created habitat heterogeneity.…”

Corrigendum

“…In “Birds in the Himalayas: What drives beta diversity patterns along an elevational gradient?”, which was published in issue 23, December , the funding information and Acknowledgments were incomplete. The correct information is printed below.…”