Disturbance reinforces community assembly processes differentially across spatial scales

Area of Science:

• Ecology
• Plant Community Ecology
• Trait-based Ecology

Background:

• Limited research exists on how spatial scale and disturbance interact to shape plant communities.
• A trait dispersion-based conceptual model was proposed to explain these interactions.
• Understanding these dynamics is crucial for predicting community assembly and managing invasive species.

Purpose of the Study:

• To test a conceptual model hypothesizing that disturbance differentially reinforces plant community assembly processes across spatial scales.
• To evaluate how disturbance affects functional and species richness of native and exotic plants.
• To assess the role of trait dispersion in community assembly under varying disturbance regimes.

Main Methods:

• Field study in an arid shrubland using nested quadrats (neighbourhood, patch) along a natural disturbance gradient.
• Estimation of species richness and functional dispersion/richness.
• Meta-analysis and quantitative literature review to test the conceptual model across scales.

Main Results:

• Disturbance promoted functional divergence at the neighbourhood scale, random trait dispersion at the patch scale, and functional convergence at the site scale.
• Functional richness remained unaffected by disturbance across all scales.
• Disturbance favored native species at the neighbourhood scale but reduced both native and exotic species richness at larger scales.

Conclusions:

• The study supports the hypothesis that disturbance effects on assembly processes vary significantly with spatial scale.
• The conceptual model successfully predicted differential assembly processes across scales.
• Disturbance was found to inhibit plant invasions, particularly at larger spatial scales.