Borealization and its discontents: drivers of regional variation in plant diversity across scales in interior Alaska

• Published in: Ecosphere
• Main Authors: Roland, Carl, Schmidt, Joshua H., Stehn, Sarah E., Hampton‐Miller, Celia J., Nicklen, E. Fleur
• Other Authors: National Park Service
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2021
• Subjects: Alaska; Beringia
• Online Access: http://dx.doi.org/10.1002/ecs2.3485; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.3485; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ecs2.3485; https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.3485

Abstract Quantitative studies of regional variation in plant diversity across eastern Beringia (northern Alaska and adjacent areas) are lacking due to an absence of datasets of sufficient scale and scope. We interrogated a landscape‐scale plant diversity dataset collected across two regions of interior Alaska with different disturbance, topographic, and climate attributes to investigate hypotheses regarding drivers of plant species richness. Our approach integrated a multi‐scale sampling design with an analytical framework focused on quantifying how components of plant diversity (growth forms, biogeographic groups, and dominant species) respond to site factors that vary along landscape gradients. Our results revealed essential similarities in both the composition of the overall floras and the influences on local and meso‐scale species richness across both regions. However, these continuities at smaller scales contrasted with differences in landscape‐level distribution of plant diversity patterns along elevation gradients. Our findings suggest that local drivers of richness and occupancy interacted with differing macro‐scale attributes (e.g., relative continentality) to produce distinctive landscape‐level diversity patterns. Our results confirm that high levels of local and meso‐scale plant richness in interior Alaska depend on conditions that foster richness of herbaceous and northerly distributed species groups. However, we found that important differences in landscape‐level richness patterns were driven by regional differences in climate, topoedaphic variables, and disturbance. In the warmer region, woody species and boreal plant communities extended to higher elevations and common species occupancy showed marginally greater influence of fire. Overall richness was relatively low in alpine areas of the warmer region but heterogeneous edaphic and topographic circumstances stimulated higher species turnover in lower elevations there, increasing landscape‐level richness. In contrast, in the cooler region, woody ...