Microclimate and Dry Years Interfere With Landscape Structure Effects on Intraspecific Trait Variation

Area of Science:

• Ecology
• Conservation Biology
• Plant Trait Variation

Background:

• Predicting the combined effects of climate and land use on populations is critical.
• Microclimate influences species persistence by modifying regional weather impacts.
• Limited empirical data exists on how landscape structure and microclimate affect intraspecific trait variation.

Purpose of the Study:

• To assess the relative impacts of landscape structure, microclimate, and weather on plant trait variation.
• To determine if microclimate (heat load) modifies weather effects on plant traits.
• To investigate intraspecific trait variation in the grassland specialist *Salvia nemorosa* L.

Main Methods:

• Utilized a spatially and temporally replicated demographic dataset of 569 marked *Salvia nemorosa* individuals.
• Measured stem height, leaf area, stem number, and inflorescence traits over three years.
• Sampled 13 populations across varying microhabitat heat load levels.

Main Results:

• Habitat fragmentation (isolation, small fragment size) affected stem number and height.
• High heat load and dry years negatively impacted all measured plant traits.
• The detrimental effects of high heat load were amplified during dry years.

Conclusions:

• Environmental stressors can obscure the detection of human impact on plant populations.
• Conservation strategies for dry grassland species require enhanced habitat connectivity.
• Maintaining microclimates with heterogeneous conditions is vital for buffering weather extremes.