Predicting Habitat Utilization and Extent of Ecosystem Disturbance by an Increasing Herbivore Population

James D. M. Speed, Sarah Jane Woodin, Hans Tommervik, Mikkel P. Tamstorf, Rene Van Der Wal

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Herbivory can lead to shifts in ecosystem state or changes in ecosystem functioning, and recovery from herbivory is particularly slow in disturbance-sensitive ecosystems such as arctic tundra. Herbivore impacts on ecosystems are variable in space and time due to population fluctuations and selective utilization of habitats; thus there is a need to accurately predict herbivore impacts at the landscape scale. The habitat utilization and extent of disturbance caused by increasing populations of pink-footed geese (Anser brachyrhynchus) foraging in the high arctic tundra of Svalbard were assessed using a predictive model of the population's habitat use. Pink-footed geese arrive in Svalbard in early spring when they forage for belowground plant parts; this foraging (called grubbing) can cause vegetation loss and soil disturbance. Surveys of the extent and intensity of grubbing were carried out to develop predictive models that were subsequently tested against data collected during the following year from different areas. Both habitat type at a particular point and the amount of preferred fen habitat in the surrounding area were powerful predictors of grubbing likelihood and the developed model correctly classified over 69% of validation observations with an AUC of 0.75. Pink-footed geese showed a strong preference for wetter habitats within low-lying landscapes. Extrapolation of the predictive model across the archipelago showed that a maximum potential area of 2300 km(2) (3.8% of the archipelago) could be disturbed by grubbing. Thus, increasing populations of geese may cause large-scale vegetation loss and soil disturbance in arctic ecosystems.

Original languageEnglish
Pages (from-to)349-359
Number of pages11
JournalEcosystems
Volume12
Issue number3
DOIs
Publication statusPublished - Apr 2009

Keywords

  • Anser brachyrhynchus
  • ecosystem engineer
  • grubbing
  • landscape
  • Svalbard
  • tundra
  • top-down regulation
  • GIS
  • pink-footed geese
  • anser-brachyrhynchus
  • expolitation ecosystems
  • spatial-distribution
  • vegetation
  • scale
  • svalbard
  • degredation
  • impacts

Cite this