Marine diversity patterns in Australia are filtered through biogeography

Area of Science:

• Ecology
• Biogeography
• Marine Biology

Background:

• Latitudinal diversity gradients are a major ecological pattern.
• Previous studies often overlook biogeographical provinces in diversity modeling.
• Research typically focuses on species-area and local-regional relationships.

Purpose of the Study:

• Investigate correlates of latitudinal diversity patterns in Australian coastal molluscs.
• Incorporate biogeographical provinces into statistical models of diversity.
• Determine drivers of species composition and diversity across regions.

Main Methods:

• Utilized an extensive online database (>300,000 specimens) of Australian coastal molluscs.
• Quantified species diversity using four distinct methods to manage sampling variation.
• Developed a biogeographic scheme via factor analysis based on species composition, independent of diversity.

Main Results:

• Diversity patterns were not directly explained by abiotic variables alone.
• Transitions between biogeographical regions were stronger predictors of diversity.
• Biogeographic gradients, in turn, were explained by environmental variables, indicating indirect environmental control.

Conclusions:

• Biogeographical province transitions, rather than local factors, largely explain diversity variation.
• Species-energy hypothesis is challenged by findings of homogeneous faunas within provinces.
• Future research should integrate biogeographical gradients for a comprehensive understanding of diversity patterns.