Usnea antarctica, an important Antarctic lichen, is vulnerable to aspects of regional environmental change

Studies of cryptogam responses to climate change in the polar regions are scarce because these slow-growing organisms require long-term monitoring studies. Here, we analyse the response of a lichen and moss community to 10 years of passive environmental manipulation using open-top chambers (OTCs) in the maritime Antarctic region. Cover of the dominant lichen Usnea antarctica declined by 71 % in the OTCs. However, less dominant lichen species showed no significant responses except for an increase in Ochrolechia frigida, which typically covered dying lichen and moss vegetation. There were no detectable responses in the moss or associated micro-arthropod communities to the influence of the OTCs. Based on calculated respiration rates, we hypothesise that the decline of U. antarctica was most likely caused by increased net winter respiration rates (11 %), driven by the higher temperatures and lower light levels experienced inside the OTCs as a result of greater snow accumulation. During summer, U. antarctica appears unable to compensate for this increased carbon loss, leading to a negative carbon balance on an annual basis, and the lichen therefore appears to be vulnerable to such climate change simulations. These findings indicate that U. antarctica dominated fell-fields may change dramatically if current environmental change trends continue in the maritime Antarctic, especially if associated with increases in winter snow depth or duration

Functioning of terrestrial ecosystems of the Maritime Antarctic in a warmer climate

Aerts, M.A.P.A. [Promotor]Huiskes, A.H.L. [Copromotor]Convey, P. [Copromotor

Impact of marine vertebrates on Antarctic terrestrial micro-arthropods

Traits of primary producers associated with tissue quality are commonly assumed to have strong control over higher trophic levels. However, this view is largely based on studies of vascular plants, and cryptogamic vegetation has received far less attention. In this study natural gradients in nutrient concentrations in cryptogams associated with the proximity of penguin colonies on a Maritime Antarctic island were utilized to quantify the impact of nitrogen content on micro-arthropod communities. Proximity to penguin colonies increased the nitrogen concentration of cryptogams, and the penguin source was confirmed by decreasing δ15N values at greater distances from colonies. Micro-arthropod abundance, diversity (H’) and richness declined with distance from the penguin colonies, and was positively correlated with the nitrogen concentrations of cryptogams. Δ15N of micro-arthropods was positively correlated (r2=0.865, P<0.01) with δ15N of the moss Andreaea depressinervis indicating that penguin-derived nitrogen moves through Antarctic food webs across multiple trophic levels. Nitrogen content of cryptogams was correlated with associated micro-arthropods indicating that biotic interactions affect community development in Antarctic terrestrial ecosystems. The spatial patterns of Antarctic biodiversity can therefore be affected by local factors, such as marine vertebrates, beyond existing latitudinal patterns of temperature and water availability

Trophic relationships in soil communities: how abiotic stress affects biotic interactions in the McMurdo Dry Valleys, Antarctica

2018 Summer.Includes bibliographical references.To view the abstract, please see the full text of the document

Colonizing polar environments : thermal niche evolution in Collembola

DATA AVAILABILITY STATEMENT : Data are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.4j0zpc8gb (Escribano-Álvarez et al. 2023).Please read abstract in the article.The Ministry of Science & Innovation under the call for International Joint Programming, a FPI contract, an EU-Biodiversa project ASICS granted by the South African National Research Foundation.https://onlinelibrary.wiley.com/journal/16000587hj2023Plant Production and Soil ScienceSDG-15:Life on lan