Intraspecific genetic diversity matters: Genetic lineages of Solanum elaeagnifolium show contrasting responses to climate change across time

Abstract

Semiarid environments dominate southern South America. These regions are highly vulnerable to climate change and prone to undergo the consequent shifts in species distribution. Solanum elaeagnifolium is common in the Chaco and Monte ecoregions, where two distinct genetic lineages have been identified. This study aimed to determine whether these lineages are associated with different climatic conditions, to characterize their climatic niches, and to analyze their responses to past and future climate change. We used phylogeographic and ecological approaches. Individuals of S. elaeagnifolium were sequenced to determine their lineage; subsequently, we analyzed the bioclimatic envelope of each lineage and developed ecological niche models (ENMs) to reconstruct their current, historical, and potential future distributions, as well as to define their niches. One lineage, referred to as the yellow lineage, predominates in the lowland Dry Chaco and Monte ecoregions, while the other, hereafter the blue lineage, is more common in the Humid Chaco and in the Sierras Pampeanas within the Dry Chaco, likely reflecting differences in precipitation requirements. Niche comparisons between S. elaeagnifolium lineages showed that their niche overlap is likely due to chance. According to the ENM results, the yellow lineage has maintained a relatively stable distribution throughout glacial cycles, whereas the blue lineage shows more dynamic shifts. Future projections suggest a stable range for the blue lineage and a contraction for the yellow lineage. This study underscores the importance of considering intraspecific genetic and ecological variability to understand a species’ evolutionary history and ecological preferences, with implications for management and conservation.