Willow drives changes in arthropod communities of northwestern Alaska: Ecological implications of shrub expansion

By: , and 



Arthropods serve as complex linkages between plants and higher-level predators in Arctic ecosystems and provide key ecosystem services such as pollination and nutrient cycling. Arctic plant communities are changing as tall woody shrubs expand onto tundra, but potential effects on arthropod abundance and food web structure remain unclear. Changes in vegetation structure can alter the physical habitat, thermal environment, and food available to arthropods, thereby having the potential to induce cascading effects throughout the ecosystem. We evaluated relationships between the abundance, biomass, and community composition of arthropods and the cover of several shrub taxa across tundra–shrub gradients in northwestern Alaska. While previous research had found a general positive association between arthropod biomass and shrub cover, we found heterogeneity in this relationship with finer-scale examination of (1) shrub taxa, (2) arthropod taxa, and (3) arthropod guilds. Abundance and biomass of arthropods showed strong, positive associations with the amount of cover of willow (Salix spp.) but were not significantly influenced by shrub birch (Betula spp.) or ericaceous (Ericaceae) vegetation. Significant shifts in arthropod community composition were also associated with willows. Among trophic groups of arthropods, herbivores and pollinators were most positively associated with willow cover. Due to geographical variation in both dominant shrub taxa and their rates of expansion, effects on arthropod communities are likely to be heterogeneous across the Arctic. Taken together, our results suggest that shrub expansion could increase food availability for higher-level insectivores and shift Arctic food web structure.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Willow drives changes in arthropod communities of northwestern Alaska: Ecological implications of shrub expansion
Series title Ecosphere
DOI 10.1002/ecs2.3514
Volume 12
Issue 5
Year Published 2021
Language English
Publisher Ecological Society of America
Contributing office(s) Alaska Science Center Biology WTEB
Description e03514, 17 p.
Country United States
State Alaska
Google Analytic Metrics Metrics page
Additional publication details