Anthropogenic landâuse impacts on the size structure of macroinvertebrate assemblages are jointly modulated by local conditions and spatial processes.
Environ Res
; 204(Pt B): 112055, 2022 03.
Article
in En
| MEDLINE
| ID: mdl-34536372
ABSTRACT
Body size descriptors and associated resemblance measurements may provide useful tools for forecasting ecological responses to increasing anthropogenic landâuse disturbances. Yet, the influences of agriculture and urbanisation on the size structure of biotic assemblages have seldom been investigated in running waters. Using a comprehensive dataset on stream macroinvertebrates from 21 river basins across Western Finland, we assessed whether the structure of assemblages via changes in taxonomic composition and body size distributions responded predictably to anthropogenic landâuse impacts. Specifically, we applied a combination of resemblance measurements based on cumulative abundance profiles and spatially constrained null models to understand faunal impairment by agricultural and urban development, and the most likely mechanisms underlying the observed shifts in assemblage size structure. Anthropogenically impacted stream sites showed less variation in assemblage composition and size distributions compared with leastâdisturbed sites, with strong declines in internal variation also occurring for the transition from nearâpristine to moderately impacted landscapes. These results were consistent whether based on speciesâlevel or genusâlevel data. Variation in assemblage size structure seemed to be more predictable than taxonomic composition, supporting the notion that resemblance measurements based on body size distributions can represent an improvement to more traditional approaches based on taxonomic identities alone. In addition, we showed that macroinvertebrate assemblages resulted from effects of landâuse degradation mediated through local conditions and spurious spatial structures in the distribution of anthropogenic activities across the landscape. Overall, our findings suggest that existing water policies and agriâenvironment schemes should be guided not only by understanding the individual effects of agricultural and urban development on taxonomic composition at a given stream site. Rather, we should also acknowledge the size structure of stream assemblages and whether concomitant changes in local conditions and the nonârandom distribution of human infrastructures are likely to mitigate or accelerate these effects.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Anthropogenic Effects
/
Invertebrates
Type of study:
Prognostic_studies
Limits:
Animals
/
Humans
Language:
En
Journal:
Environ Res
Year:
2022
Document type:
Article