Exploring rarity using a general model for distribution and abundance

Area of Science:

• Ecology
• Population Biology
• Theoretical Ecology

Background:

• Understanding species rarity is crucial for conservation biology.
• Metapopulation dynamics, involving interconnected local populations, are key to species persistence.
• Factors influencing distribution and abundance are complex and require theoretical modeling.

Purpose of the Study:

• To develop a simple model for metapopulation distribution and abundance changes.
• To explore conditions leading to various forms of species rarity.
• To provide a theoretical foundation for population dynamics influencing distribution and abundance.

Main Methods:

• Development of a simple metapopulation model.
• Analysis of model outputs to identify conditions for different rarity types.
• Exploration of the relationship between local extinction, dispersal, and heterogeneity.

Main Results:

• Localized populations result from low dispersal and high local extinction.
• Scarce populations arise from moderate extinction rates and high heterogeneity or low dispersal.
• Sparse populations are linked to very low extinction rates and high heterogeneity or dispersal mortality.
• A correlation between distribution and abundance is supported, with thresholds for persistence.

Conclusions:

• Metapopulation persistence can be threatened by both too high and too low dispersal rates.
• The model offers a new perspective on rarity by linking it to specific population-dynamic mechanisms.
• Theoretical insights into rarity can inform conservation strategies and biodiversity management.