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Local snowmelt and temperature – but not regional sea‐ice – explain variation in spring phenology in coastal Arctic tundra

Research output: Contribution to journalArticle

Original languageEnglish
JournalGlobal Change Biology
DOIs
Publication statusPublished - 8 Apr 2019

Abstract

The Arctic is undergoing dramatic environmental change with rapidly rising surface temperatures, accelerating sea‐ice decline and changing snow regimes, all of which influence tundra plant phenology. Despite these changes, no globally consistent direction of trends in spring phenology has been reported across the Arctic. While spring has advanced at some sites, spring has delayed or not changed at other sites, highlighting substantial unexplained variation. Here, we test the relative importance of local temperatures, local snowmelt date and regional spring drop in sea‐ice extent as controls of variation in spring phenology across different sites and species. Trends in long‐term time‐series of spring leaf out and flowering (average span: 18 years) were highly variable for the 14 tundra species monitored at our four study sites on the Arctic coasts of Alaska, Canada and Greenland, ranging from advances of 10.06 days per decade to delays of 1.67 days per decade. Spring temperatures and the day of spring drop in sea‐ice extent advanced at all sites (average 1 °C per decade and 21 days per decade respectively), but only those sites with advances in snowmelt (average 5 days advance per decade) also had advancing phenology. Variation in spring plant phenology was best explained by snowmelt date (mean effect: 0.45 days advance in phenology per day advance snowmelt) and, to a lesser extent, by mean spring temperature (mean effect: 2.39 days advance in phenology per °C). In contrast to previous studies examining sea ice and phenology at different spatial scales, regional spring drop in sea‐ice extent did not predict spring phenology for any species or site in our analysis. Our findings highlight that tundra vegetation responses to global change are more complex than a direct response to warming and emphasize the importance of snowmelt as a local driver of tundra spring phenology.

ID: 82520818