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Modeling the Size Spectrum for Macroinvertebrates and Fishes in Stream Ecosystems

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Scale dependency in native-exotic richness relationships revisited.

¹USDA FS Eastern Forest Environmental Threat Assessment Center Research Triangle Park North Carolina USA.

Ecology and Evolution

|February 7, 2022

Summary

The Shea and Chesson (S&C) model

Area of Science:

Ecology
Invasion Biology
Biodiversity Science

Background:

The original Shea and Chesson (S&C) model demonstrated scale-dependent native-exotic richness relationships.
Two decades of research have yielded new data and insights into ecological community dynamics.

Purpose of the Study:

To update the S&C model based on accumulated data and recent findings.
To re-evaluate the relationship between native and exotic species richness across different spatial scales.

Main Methods:

Modification of the original S&C model's assumptions regarding native-exotic richness.
Revision of the S&C model's graphical representation to accurately depict species richness correlations.

Main Results:

Keywords:

biotic resistance diversity invasibility model species invasion

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The previously assumed negative relationship between native and exotic richness was found to be non-consistent or non-significant.

Updated diagrams reflect a more nuanced understanding of native and exotic species richness across scales.

Conclusions:

The relationship between native and exotic species richness is more complex than initially proposed by the S&C model.
Ecological research should consider scale dependency and updated empirical data when examining invasion dynamics.