Beyond species-level planning: The role of bioclimatic variation within species distributions

Conserving biodiversity under a changing climate is a complex challenge that requires comprehensive conservation planning approaches accounting for both current biodiversity patterns and the diverse ecological and environmental changes that species and ecosystems are likely to encounter over time. Systematic conservation planning (SCP) offers a strategic framework to meet this challenge by prioritizing areas that promote species persistence and ecological resilience. Traditionally, SCP focuses on conserving adequate amounts of species distributions to ensure their long-term persistence. More recently, partitioning species distributions into bioclimatic components has emerged to explicitly represent niche variability, enhancing adaptive capacity by preserving local adaptations and genetic diversity across environmental gradients. Despite this conceptual progress, empirical comparisons of species-level and bioclimatic component prioritization remain scarce. This study aimed to compare species-level and bioclimatic component prioritization by assessing their trade-offs and effectiveness in supporting species persistence and ecological resilience. Specifically, we aimed to (i) assess the surrogacy between species-level and bioclimatic component prioritizations, (ii) examine their spatial overlap and divergence, and (iii) quantify and compare environmental heterogeneity within priority areas identified by each approach. We found that species-level and bioclimatic component prioritizations act as reasonable surrogates for one another overall, but species-level prioritization tended to underrepresent the least-covered bioclimatic components, with failures to capture certain components in the top-ranked areas. Spatial overlap between the two approaches was generally high, though it declined with more restrictive thresholds and under future conditions. Additionally, bioclimatic component prioritizations consistently captured higher within-group multivariate dispersion in environmental heterogeneity in selected areas. Our findings highlight that bioclimatic component prioritization captures greater environmental heterogeneity and complements species-based approaches by better representing niche diversity. Integrating both strategies may offer a more robust path toward climate-resilient conservation planning that accounts for ecological requirements and environmental variation.