Intraspecific Niche Models for Ponderosa Pine (Pinus ponderosa) Suggest Potential Variability in Population-Level...

Area of Science:

• Ecology
• Climate Change Biology
• Conservation Genetics

Background:

• Intraspecific variation influences species' responses to climate change, necessitating models that account for genetically distinct populations.
• Predictive distribution models often overlook intraspecific variation, focusing on species-level analyses due to data limitations.
• Ponderosa pine (Pinus ponderosa) exhibits significant morphological and genetic variation, with distinct varieties and haplotypes occupying unique climatic niches.

Purpose of the Study:

• To investigate the role of intraspecific variation in shaping the geographic distribution of ponderosa pine under climate change.
• To model and project the future distributions of ponderosa pine varieties and haplotypes using ecological niche models (ENMs).
• To assess the utility of lineage distance modeling and niche-overlap analysis for understanding intraspecific responses to climate change.

Main Methods:

• Utilized a widespread dataset of ponderosa pine haplotypes and a lineage distance modeling approach to identify potential intraspecific occurrence locations.
• Confirmed the uniqueness of haplotype-climate relationships through niche-overlap analysis.
• Developed ENMs to project current and future distributions for two varieties and eight haplotypes under climate change scenarios.

Main Results:

• Future projections indicated greater potential range loss for ponderosa pine haplotypes compared to varieties, suggesting distinct evolutionary lineage responses.
• Directional trends across intraspecific levels included significant loss of distributional area and an upward shift in elevation.
• Niche-overlap analysis confirmed the relative climatic uniqueness of each haplotype.

Conclusions:

• Modeling intraspecific variation is essential for accurately predicting species' responses to climate change.
• Distinct evolutionary lineages within ponderosa pine exhibit unique vulnerabilities and resilience to climate change.
• Results inform targeted management and conservation strategies by identifying at-risk or secure haplotypes and geographic areas.