Species‐Specific Traits Shape Genetic Diversity During an Expansion–Contraction Cycle and Bias Demographic History Reconstruction

ABSTRACT Species ranges are dynamic, experiencing expansions, contractions or shifts in response to habitat changes driven by extrinsic factors such as climate change or human activities. While existing research examines the genetic consequences of spatial processes, few studies integrate species‐specific traits to analyse how habitat changes affect co‐existing species. In this study, we address this gap by investigating how genetic diversity patterns vary among species with different traits (such as generation length, population density and dispersal) experiencing similar habitat changes. Using spatial simulations and a simpler panmictic population model, we investigate the temporal genetic diversity in refugium populations undergoing range expansion of their habitat, followed by stationary and contraction periods. By varying habitat contraction speed and species traits, we identified three distinct temporal dynamics of genetic diversity during contraction: (i) a decrease in genetic diversity, (ii) an initial increase followed by a decrease and (iii) a continuous increase throughout the contraction period. We show that genetic diversity trajectories during population decline can be predicted by comparing sampled population diversity to equilibrium values expected under expanded and contracted habitat ranges. Our study also challenges the belief that high genetic diversity in a refugium population is due to a recent and rapid habitat loss. Instead, we found contrasting effects of contraction speed on genetic diversity depending on the interaction between species‐specific traits and the dynamics of habitat change. Finally, using simulated genetic data, we found that demographic histories inferred from effective population size estimates may vary across species, even when they experience similar habitat changes. प्रजाति यों की पर्या वास गति शील हैं, जो जलवायु परि वर्तन या मानवीय गति वि धि यों जैसे बाहरी कारकों से प्रेरि त परि वर्तनों के कारण वि स्तार, संकुचन या बदलाव का अनुभव कर रही हैं। हालांकि मौजूदा शोध स्थानि क प्रक्रि याओंके आनुवंशि क प्रभावों की जांच करतेहैं, लेकि न केवल कुछ अध्ययनों मेंयह वि श्लेषण कि या गया है कि नि वास स्थान परि वर्तन वि भि न्न प्रजाति यों के लक्षणों के साथ सह‐मौजूदा प्रजाति यों को कैसेप्रभावि त करते हैं। इस अध्ययन में हम यह जांच करते हैं कि समान नि वास स्थान परि वर्तन का अनुभव करनेवाले वि भि न्न लक्षणों वाली प्रजाति यों (जैसे पीढ़ी की लंबाई, जनसंख्या घनत्व और प्रव्रजन) के बीच आनुवंशि क वि वि धता प्रति मान कैसे भि न्न होते हैं। स्था