Evolved dispersal strategies at range margins.

Area of Science:

• Ecology
• Evolutionary Biology
• Conservation Biology

Background:

• Dispersal is a critical ecological process influencing species distribution and adaptation.
• Selection pressures on dispersal strategies differ across a species' geographic range, particularly between range cores and margins.
• Understanding these varied pressures is vital for predicting species responses to environmental change.

Purpose of the Study:

• To investigate how dispersal strategies evolve under varying environmental conditions across a species' range.
• To determine the impact of factors like habitat loss, turnover, and dispersal costs on dispersal evolution.
• To identify which populations' dispersal capabilities are most influential for range shifts.

Main Methods:

• Utilized a spatially explicit, individual-based, evolutionary simulation model.
• Simulated organisms with a single dispersal event in their lifetime (e.g., plants, sessile animals).
• Manipulated habitat characteristics (removal, turnover, quality, density) and vital rates (birth, death) to simulate range limits.

Main Results:

• Evolved dispersal strategies showed significant variation across the simulated range.
• Habitat turnover, reduced birth rates, and lower habitat quality increased dispersal distances at the range margin.
• Increased dispersal costs and reduced habitat density decreased dispersal distances at the margin.

Conclusions:

• Marginal populations' dispersal strategies are key drivers of range shifts, especially under climate change.
• Environmental factors at the range edge critically shape dispersal evolution and thus range dynamics.
• Conservation and management strategies must consider the unique adaptive capacities of marginal populations.