Environmental niche equivalency versus conservatism: quantitative approaches to niche evolution

Area of Science:

• Ecology
• Evolutionary Biology
• Biogeography

Background:

• Environmental niche models integrate species occurrence and GIS data to study niche evolution and ecological diversity.
• Niche conservatism over evolutionary time is debated, with conflicting conclusions often stemming from varied measurement methods and null hypotheses.

Purpose of the Study:

• To develop novel methods for quantifying niche overlap and reexamine niche conservatism.
• To address alternative definitions of niche conservatism within a unified framework.
• To explore niche divergence in adaptive radiations.

Main Methods:

• Development of new niche overlap quantification methods using ecological and statistical metrics.
• Reexamination of niche conservatism in Mexican animal sister species.
• Analysis of niche divergence in Cuban anole adaptive radiation using phylogenetic comparative methods.

Main Results:

• Environmental niches of sister species show greater similarity than predicted by three distinct null hypotheses, though rarely identical.
• Environmental niche overlap correlates with geographic overlap but not phylogenetic distance in Cuban anoles.
• Niche conservatism does not appear to constrain local communities to closely related species in the anole radiation.

Conclusions:

• The developed methods provide a consistent framework for assessing niche conservatism and divergence.
• Niche similarity is a common pattern, but niche identity is rare, highlighting the complexity of niche evolution.
• Randomization tests can be valuable tools for future ecological and evolutionary studies.