Nitrogen Inputs by Marine Vertebrates Drive Abundance and Richness in Antarctic Terrestrial Ecosystems

Stef Bokhorst*, Peter Convey, Rien Aerts

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

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Abstract

Biodiversity is threatened by climate change and other human activities [1], but to assess impacts, we also need to identify the current distribution of species on Earth. Predicting abundance and richness patterns is difficult in many regions and especially so on the remote Antarctic continent, due to periods of snow cover, which limit remote sensing, and the small size of the biota present. As the Earth's coldest continent, temperature and water availability have received particular attention in understanding patterns of Antarctic biodiversity [2], whereas nitrogen availability has received less attention [3]. Nitrogen input by birds is a major nutrient source in many regions on Earth [4–7], and input from penguins and seals is associated with increased plant growth [8–10] and soil respiration [11–13] at some Antarctic locations. However, the consequences of increased nitrogen concentrations in Antarctic mosses and lichens for their associated food web has hardly been addressed [14, 15], despite the fact that nutrient status of primary producers affects the abundance and diversity of higher trophic levels [16, 17]. We show that nitrogen input and δ 15 N signatures from marine vertebrates are associated with terrestrial biodiversity hotspots well beyond (>1,000 m) their immediate colony borders along the Antarctic Peninsula. Invertebrate abundance and richness was two to eight times higher under penguin and elephant seal influence. The nitrogen footprint area was correlated with the vertebrate population size. These findings improve our ability to predict biogeographical patterns of Antarctic terrestrial biodiversity through knowledge of the location and size of penguin and elephant seal concentrations. Bokhorst et al. show that the location and size of Antarctic terrestrial biodiversity hotspots can be predicted from the presence of penguin colonies and elephant seal aggregations. Increased abundance and richness of terrestrial invertebrates is linked to the marine-derived nitrogen through δ 15 N, which extends well beyond the colony borders.

Original languageEnglish
Pages (from-to)1721-1727.e3
Number of pages11
JournalCurrent Biology
Volume29
Issue number10
Early online date9 May 2019
DOIs
Publication statusPublished - 20 May 2019

Keywords

  • biogeography
  • cryptogam
  • elephant seal
  • invertebrate
  • isotope
  • lichen
  • mite
  • moss
  • nematode
  • nitrogen
  • penguin
  • polar
  • springtail

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