Bumblebee Diversity in Different Habitat Types and Along an Altitudinal Gradient at a Forest–Grassland Ecotone in the East Range of the Qinghai–Tibet Plateau

TL;DR

This study explores bumblebee diversity in different habitats and altitudes in a forest-grassland area of the Qinghai-Tibet Plateau, finding that alpine meadows support the highest diversity.

Contribution

The study provides new insights into bumblebee distribution patterns in relation to habitat types and altitude in a high-altitude ecotone.

Findings

Alpine meadows had the highest bumblebee species richness and abundance compared to shrubs and grasslands.

Bumblebee diversity showed two peaks at altitudes of 3500–3700 m and 2900–3100 m, with lower diversity in overgrazed grasslands at 3100–3500 m.

Environmental factors significantly influence bumblebee diversity, and conservation efforts should prioritize alpine meadows.

Abstract

This study investigates bumblebee diversity in the headwater region of the Bailong River, China, focusing on the effects of habitat types, altitude, and human disturbance. To comprehend the variation in bumblebee diversity in different habitat types and along an altitudinal gradient, this study carried out transect counting in three distinct habitat types and along an altitudinal gradient in the source area of the Bailong River. The result indicates (1) high species richness of bumblebees in headwater region of Bailong River. It indicates that the Forest–Grassland ecotone has rich bumblebee diversity. Edge effects and suitable habitats supported high bumblebee richness. (2) Species richness and abundance differed between three habitat types: alpine meadows had the highest; shrubs on the forest edge had the second highest; and grasslands had the lowest. (3) The distribution pattern in the altitude of bumblebees shows two peaks. The species richness and abundance of bumblebee are highest in the ranges of 3500–3700 m and 2900–3100 m, while 3100–3500 m is lower than the other altitude ranges, presumably because this range is just a large grassland with overgrazing. (4) The results of redundancy analysis indicate that environmental factors significantly affect the diversity of bumblebees. (5) The conservation measures should mainly focus on alpine meadows, as they are the most important habitat of the bumblebee. Reducing overgrazing in large-scale grassland is beneficial to bumblebees, as well as wildflower plants.

Bumblebees are the most important pollinators in alpine areas. Their survival is vulnerable to anthropogenic disturbance. To comprehend the variation in bumblebee diversity in different habitat types and altitudinal gradient, this study carried out transect counting in three distinct habitat types and altitudinal gradient in the source area of the Bailong River between June and September from 2021 to 2022. The result indicates (1) high species richness in bumblebees, as 27 species and 1106 individuals from 9 subgenera were collected. It indicates that the Forest–Grassland ecotone has rich bumblebee diversity. Edge effective and suitable habitats bred rich bumblebees. (2) Species richness and abundance differed between three habitat types: alpine meadows had the highest; shrubs on the forest edge had the second highest; and grasslands had the lowest. (3) The distribution pattern in the altitude of bumblebees shows two peaks. The species richness and abundance of bumblebee are highest in the ranges of 3500–3700 m and 2900–3100 m, while 3100–3500 m is lower than the other altitude ranges, presumably because this range is just a large grassland with overgrazing. (4) The results of redundancy analysis indicate that environmental factors significantly affect the diversity of bumblebees. (5) The conservation measures should mainly focus on alpine meadows, as they are the most important habitat of the bumblebee. Reducing overgrazing in large-scale grasslands is beneficial to bumblebees as well as wildflower plants.

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