- Buyens I.P.R., Raath-Krüger M.J., Haddad W.A. & le Roux P.C.
- Journal of Vegetation Science
- 34: e13200 [16 p.]
Question: Plant–plant interactions can strongly influence community structure and
composition. The outcome of these interactions can vary considerably across space
and is often linked to environmental conditions, with, for example, a higher prevalence of facilitative interactions typically being observed under greater environmental
severity. To date, most studies have documented shifts from competitive to facilitative (or neutral) plant–plant and plant–lichen interactions along gradients of increasing
environmental severity from pairwise interspecific interactions. However, few studies
have examined if the outcome of these interactions for different taxonomic groups
is dependent on environmental conditions across multiple environmental stress
Location: Sub-Antarctic Marion Island.
Methods: We examine community-level variation in the response of four taxa (i.e.,
vascular plants, hepatics, mosses, and lichens) to an interaction with a long-lived cushion plant species (Azorella selago) that ameliorates microenvironmental conditions,
testing how the effect of the cushion plant on the taxa varies along multiple stress
gradients at the scale of a landform.
Results: Contrary to expectations, even when considering multiple proximate predictor variables, fine-scale spatial variation in the effect of A. selago on the taxa could
not be explained. However, the outcome of the interaction with A. selago differed between taxonomic groups, with vascular plants benefitting and the non-vascular taxa
experiencing neutral or negative impacts.
Conclusions: This study highlights that the impacts of biotic interactions cannot always be generalized across plant groups, and that it is necessary to consider taxonspecific responses when predicting community-level impacts of biotic interactions.
More generally, we demonstrate how complex spatial variation in environmental
stressors can be explicitly considered when modelling variation in the outcome of
Keywords: cushion plant, facilitation, fine-scale variation, plant–lichen communities, plant–lichen
interactions, plant–plant interactions, proximal variables, stress gradient, sub-Antarctic.
- Saturday, 23 September 2023 02:07