Better environmental data may reverse conclusions about niche- and dispersal-based processes in community assembly

Area of Science:

• Community Ecology
• Ecological Niche Theory
• Spatial Ecology

Background:

• Variation partitioning is used to distinguish niche- and dispersal-based processes in community assembly.
• Interpreting these processes relies heavily on the quality of environmental data used.
• Previous studies often used only topographical variables, potentially limiting ecological insights.

Purpose of the Study:

• To investigate how including soil variables impacts conclusions about niche versus dispersal processes.
• To analyze the influence of environmental data quality on community assembly interpretations.
• To apply multiscale decomposition to the pure spatial component for deeper analysis.

Main Methods:

• Variation partitioning of species composition using environmental and spatial variables.
• Comparison of analyses using only topographical data versus topography plus soil data.
• Multiscale decomposition of the pure spatial component ([c]) in variation partitioning.

Main Results:

• Analysis with only topography indicated dispersal-based processes dominate.
• Inclusion of soil variables reversed the findings, favoring niche-based processes.
• Multiscale decomposition revealed broad-scaled spatial variation with topography alone, suggesting unmeasured variables; this pattern shifted to meso- and fine-scaled patterns with soil data.

Conclusions:

• The choice of environmental variables significantly alters the perceived drivers of community assembly.
• Soil variables are crucial for accurately assessing the relative importance of niche and dispersal processes.
• Multiscale spatial patterns provide nuanced insights into the interplay of environmental and dispersal factors.