The Impact of Urbanization on the Functions Supported by Arthropods: A Global Meta-Analysis

Abstract

Aim

Urbanization poses a significant challenge to terrestrial biodiversity, yet how different urban matrices drive functional responses across varying spatial scales remains unclear. We evaluated how urbanization impacts arthropod-mediated ecosystem functions across different taxonomic groups and spatial scales, testing the hypothesis that environmental filtering in urban areas leads to scale-dependent functional responses.

Location

Global.

Methods

We conducted a meta-analysis synthesizing 398 effect sizes from 81 primary studies that investigated the effects of urbanization on critical ecological functions supported by insects: pollination, nutrient cycling, herbivory, and biological control. We evaluated scale-dependence by categorizing urbanization metrics into distinct spatial buffers and tested for variation across functions and taxonomic groups using multi-level meta-analytical models.

Results

Our main findings reveal that urbanization has no global, unidirectional effect on overall arthropod functionality. However, functional responses were highly variable and context-dependent, shifting significantly across specific taxa, ecological functions, and localized habitat types. The direction and magnitude of urbanization impacts were modulated by habitat heterogeneity captured at distinct spatial scales.

Main Conclusions

Merely classifying an area as ‘urban’ is insufficient to predict its effects on ecosystem services. The relationship between urbanization, biodiversity, and ecosystem functioning is multifaceted, scale-dependent, and heavily influenced by context. Biogeographical and urban conservation assessments must prioritize multi-scale, context-aware approaches to accurately guide urban planning and safeguard functional biodiversity.