The checkerboard score and species distributions

Area of Science:

• Ecology
• Biogeography
• Community Ecology

Background:

• Determining if species distributions are random is a persistent ecological challenge.
• Previous work indicated non-random patterns in Vanuatu avifauna but lacked causal clarity.
• This study investigates the causes and directionality of exceptional species distributions.

Purpose of the Study:

• To further examine the causes of non-random species distribution patterns.
• To quantify "checkerboardedness" in ecological communities.
• To test the hypothesis of random species colonization in island ecosystems.

Main Methods:

• Utilized Diamond's "checkerboard" distribution concept and developed a C-score statistic.
• Generated "control groups" of random colonization patterns using established simulation methods.
• Employed data perturbation techniques to create alternative control datasets.

Main Results:

• Vanuatu avifauna and Antillean bat communities display significantly high checkerboard distributions.
• Comparison with simulated random colonization patterns revealed significant deviations.
• The observed non-randomness challenges the null hypothesis of random species assembly.

Conclusions:

• Species distributions in the studied communities are not random.
• Checkerboard patterns suggest non-random processes, likely interspecific interactions, shape these communities.
• The hypothesis of random colonization is rendered implausible for these island ecosystems.