From geographic distribution to regeneration: microhabitat regulation of plant niches in peatlands

Microhabitats play a crucial role in linking macroclimatic conditions with local plant establishment, yet current research often fails to capture the fine-scale processes shaping species’ responses in natural environments. The characteristic repetitive hummock-hollow structures in peatlands provide an ideal model system to test this because the microhabitats differ markedly in hydrologic and nutrient conditions. This study aimed to examine how hummocks and hollows drive species differentiation in geographic distribution, climatic niche, and regeneration niche, and to compare the responses of tracheophytes and bryophytes. We are building a comprehensive database of 41 peatland species of tracheophytes and bryophytes. Based on global occurrence records (GBIF, CVH), we estimated species’ geographic range size and climatic niche. Regeneration niche breadth was further evaluated using dormancy-breaking treatments and germination responses across temperature regimes. At the geographic scale, microhabitat type did not significantly affect species’ geographic range or climatic niche centers. Instead, climatic adaptation diverged between taxa: tracheophytes primarily broadened their niche breadth, while bryophytes relied more on niche symmetry. At the regeneration scale, tracheophyte species from variable hummocks exhibited broader regeneration niche through shallow-dormancy strategies, whereas hollow species adopted deep-dormancy “best-bet” strategies. In contrast, bryophytes showed wider regeneration niche breadth than tracheophytes. Microhabitats do not directly determine species’ macro-distribution but act as environmental filters that shape life-history strategies during regeneration, thereby indirectly regulating species niche and distribution. Our results highlight the importance of linking micro-scale processes with geographic scale patterns and demonstrate that tracheophytes and bryophytes adopt fundamentally different adaptive strategies when facing environmental change.