Abstract:

Aims: The study aimed to clarify the variation characteristics of insect functional groups and the effects of environmental factors on their spatial distribution patterns along the altitude gradient of Guandi Mountains.

Methods: Seven typical plots with varying altitude ranging from 1,600 m to 2,800 m were established across Guandi Mountains. Insect communities across different altitude gradient were selected as the research objects. Insect specimens were collected between July and August in both 2020 and 2021 using sweeping net method and pitfall traps. One-way ANOVA was used to compare the differences in insect species diversity and functional groups at different altitudes. Three-dimensional principal component analysis and Jaccard similarity index were applied to assess the similarity of insect functional groups at different altitudes. Pearson correlation coefficient analysis and redundancy analysis were used to clarify the influence of environmental factors on the spatial distribution patterns of insect community functional groups.

Results: The results revealed a total of 9,321 insects, encompassing 11 orders, 89 families, and 198 species, across the altitudinal gradient of Guandi Mountains. The insect functional groups showed obvious differentiation characteristics along the altitude gradient. The altitudinal gradient can also significantly contribute to the differentiation in insect diversity, potentially due to the habitat heterogeneity includes communities across plots at different altitudes ranged from 0.13 to 0.41, indicating varying degrees of dissimilarity. Furthermore, all the 19 environmental factors selected in this study exhibited an effect on the spatial distribution of insect functional groups, with environmental temperature and soil P/N ratio emerging as the most important factors.

Conclusion: The diversity of insect communities and their functional groups distinctly vary along the altitude gradient. Notably, environmental temperature and soil P/N are the most important environmental factors dictating the spatial distribution pattern of insect functional groups.

Key words: Guandi Mountains, altitude gradient, insect functional groups, vertical distribution pattern