Higher Genetic Diversity Across Several Small Patches Compared to a Single Large Patch: A Within-Species Test of...

The SLOSS (Single Large or Several Small) debate is crucial in reserve design, focusing on evaluating the conservation efficacy of a single large reserve versus multiple small reserves for species preservation. While accumulating evidence suggests that multiple small reserves may conserve greater species diversity, the question of how to maximize the conservation of intraspecific genetic diversity within a fixed total area remains largely unexplored. This study evaluated the SLOSS strategy for conserving intraspecific genetic diversity in Tortula muralis using haplotype richness and phylogenetic diversity metrics. We collected 352 specimens from 28 islands within the Zhoushan Archipelago, China. Amplification of the ITS2 region yielded 78 distinct haplotypes. Following the construction of a haplotype-based phylogenetic tree, phylogenetic diversity was calculated for each island. Cumulative curves for both haplotypes and phylogenetic diversity were generated by sequentially adding islands ranked by area, following both largest to smallest and smallest to largest sequences. The results demonstrate that the genetic diversity of T. muralis is influenced by both island area and anthropogenic activities. Crucially, within a fixed total area, multiple small islands preserved significantly greater haplotype richness and phylogenetic diversity of T. muralis compared to a single large island (SS > SL). This study provides valuable insights for assessing the SLOSS strategy to conserve intraspecific genetic diversity and offers a new perspective for genetic diversity conservation.