Intraspecific Niche Evolution in a Drought Deciduous Shrub With Implications for Climate Resiliency.

Area of Science:

• Ecology
• Evolutionary Biology
• Conservation Biology

Background:

• Whitebrush (Aloysia gratissima) has distinct North and South American populations experiencing varied climates.
• This geographic isolation provides a model for studying climatic niche evolution.

Purpose of the Study:

• To identify intraspecific patterns of niche evolution in whitebrush.
• To explore how environmental variables constrain distributions and influence population-level responses to climate change.

Main Methods:

• Principal Component Analysis (PCA) to compare climatic conditions and identify climate novelty.
• Species Distribution Models (SDMs) using MaxEnt to characterize climatic niches.
• Reciprocal spatial transfers and future climate projections to assess niche equivalency and climate resiliency.

Main Results:

• Evidence of non-analogous climates and low niche overlap between populations, suggesting niche divergence.
• Differences in realized climatic niches are linked to exposure to novel environmental conditions.
• Population-level niche evolution influences climate resiliency.

Conclusions:

• Understanding niche divergence is key to predicting species' responses to climate change.
• Accounting for spatial and temporal variations in species' responses enables adaptive management strategies.