Testing the Stress-Gradient Hypothesis at the Roof of the World: Effects of the Cushion Plant Thylacospermum caespitosum on Species Assemblages

0397479 - BÚ 2014 RIV US eng J - Journal Article
Dvorský, Miroslav - Doležal, Jiří - Kopecký, Martin - Chlumská, Zuzana - Janatková, Kateřina - Altman, Jan - de Bello, Francesco - Řeháková, Klára
Testing the Stress-Gradient Hypothesis at the Roof of the World: Effects of the Cushion Plant Thylacospermum caespitosum on Species Assemblages.
PLoS ONE. Roč. 8, č. 1 (2013), e53514. ISSN 1932-6203. E-ISSN 1932-6203
R&D Projects: GA ČR GD206/08/H044; GA AV ČR IAA600050802
Institutional research plan: CEZ:AV0Z60050516
Institutional support: RVO:67985939
Keywords : cushion plants * facilitation * competition
Subject RIV: EH - Ecology, Behaviour
Impact factor: 3.534, year: 2013

Many cushion plants ameliorate the harsh environment they inhabit in alpine ecosystems and act as nurse plants, with significantly more species growing within their canopy than outside. These facilitative interactions seem to increase with the abiotic stress, thus supporting the stress-gradient hypothesis. We tested this prediction by exploring the association pattern of vascular plants with the dominant cushion plant Thylacospermum caespitosum (Caryophyllaceae) in the arid Trans-Himalaya, where vascular plants occur at one of the highest worldwide elevational limits. We compared plant composition between 1112 pair-plots placed both inside cushions and in surrounding open areas, in communities from cold steppes to subnival zones along two elevational gradients (East Karakoram: 4850–5250 m and Little Tibet: 5350–5850 m). We used PERMANOVA to assess differences in species composition, Friedman-based permutation tests to determine individual species habitat preferences, species habitat preferences, species-area curves to assess whether interactions are size-dependent and competitive intensity and importance indices to evaluate plant-plant interactions.
Permanent Link: http://hdl.handle.net/11104/0225154