Local adaptation at range edges: comparing elevation and latitudinal gradients.

Area of Science:

• Ecology and Evolutionary Biology
• Plant Population Genetics
• Climate Change Adaptation

Background:

• Local adaptation at species range edges is crucial for understanding distribution shifts and responses to environmental change.
• Factors influencing adaptation, such as gene flow and selection pressures, can differ significantly across various range edge types (latitudinal vs. elevational).

Purpose of the Study:

• To investigate local adaptation in Plantago lanceolata and Plantago major populations from central, latitudinal, and elevational range edges.
• To compare adaptation patterns along latitudinal (Scandinavia) and elevational (Swiss Alps) gradients.
• To assess the role of genetic diversity and differentiation in shaping adaptation at range edges.

Main Methods:

• Conducted a reciprocal transplant experiment using Plantago populations from distinct European range centers and edges.
• Employed molecular markers to characterize genetic diversity and population differentiation.
• Assessed plant performance under different environmental conditions at range centers and edges.

Main Results:

• Plantago major showed range-center adaptation but performed similarly to edge populations at range edges; P. lanceolata lacked clear local adaptation.
• Both species exhibited local adaptation in high-elevation populations compared to high-latitude ones, with the reverse not observed.
• Higher genetic diversity and lower differentiation were found along the elevational gradient compared to the latitudinal gradient.

Conclusions:

• Adaptation in some range-edge populations may enhance future climate change resilience, but responses differ between latitudinal and elevational gradients.
• High-elevation range edges appear more conducive to local adaptation than high-latitude edges.
• Gene flow is unlikely to impede adaptation in the studied range-edge populations.