Climate change shifts population structure and demographics of an alpine herb, Anemone narcissiflora ssp. sachalinensis (Ranunculaceae), along a snowmelt gradient

• Published in: Population ecology 2021-07, Vol.63 (3), p.260-271
• Main Authors: Kawai, Yuka, Kudo, Gaku
• Format: Article
• Language: English
• Subjects: alpine plant; Anemone narcissiflora; Brittleness; Climate change; Cold weather; Demographics; Demography; Distribution; Drought; global warming; Growing season; Growth rate; Habitats; Herbs; Local population; Meadows; Mountains; Population dynamics; Population growth; population matrix model; Population structure; Seed production; Seeds; Snow; Snowmelt; snowmelt time; Soil; Soil conditions; Soil moisture; Soils; Species extinction
• ISSN: 1438-3896; 1438-390X
• DOI: 10.1002/1438-390X.12089

Alpine ecosystems, characterized by cold climates and short growing seasons, are thought to be most vulnerable to climate change. Warmer temperatures and earlier snowmelt extend the growing season length and increase drought stress for alpine plants, resulting in changes to their distribution. Anemone narcissiflora ssp. sachalinensis is a perennial herb that grows in the alpine snow‐meadows of northern Japan. In the last few decades, its distribution has shifted toward later snowmelt habitat in the Taisetsu Mountains of Hokkaido. We recorded demographic data for this species at early, middle and late snowmelt habitats over four years (2009–2012), and constructed transition matrix models to evaluate how demographic parameters and population growth rate vary between local habitats along a snowmelt gradient. The proportion of reproductive plants was low and seed production was limited in the early snowmelt habitat, with drier soil conditions, in comparison to the middle and late snowmelt habitats, with moist soil conditions. Evidence of the transition from small plants to those in the reproductive stage was limited in the early snowmelt habitat, suggesting that growth was inhibited; the local population in this habitat was estimated to be sustained by seed migration from later snowmelt habitats. These results indicate that advancing snowmelt under climate change may decrease the reproductive activity and population growth rate of snow‐meadow plants if seed migration from later snowmelt populations is limited, resulting in the extinction of local populations. In this paper, we analyzed population dynamics of an alpine herb (Anemone narcissiflora) along a snowmelt gradient using transition matrix models and revealed a maintenance mechanism of local populations. Our results suggest that population dynamics varies within a large population responding to local snowmelt conditions and that global warming may cause local extinction of alpine plants in snow‐meadows.