Species richness and susceptibility to heat and drought extremes in synthesized grassland ecosystems: compositionalvsphysiological effects

• DOI: 10.1111/j.0269-8463.2004.00901.x
• Publication Date: 2004-12-08T08:52:24Z
• Authors: L. VAN PEER; I. NIJS; D. REHEUL; B. DE CAUWER
• Keywords: Complementarity (molecular biology); Dominance (genetics); Extinction (optical mineralogy)

Summary We investigated effects of declining plant species richness ( S ) on resistance to extremes in grassland communities. Synthesized model ecosystems different , grown outdoors containers, were exposed a stress peak combining heat and drought. The wave was induced experimentally by infrared irradiation free air conditions. Before the wave, more species‐rich communities produced biomass as result large positive complementarity effect that outweighed small negative selection effect. Water use during likewise enhanced which could not be attributed dominance ‘water‐wasting’ species. Instead, water consumption at high exceeded expected from changes community composition. observed enhancement resource (water) acquisition under with increasing therefore probably originated complementarity. Despite diverse communities, survival significantly less, affecting all alike. Physiological stress, recorded photochemical efficiency photosystem II electron transport, greater. composition coincided did favour would later prove intrinsically sensitive or insensitive. Complementarity for production had cost terms reduced despite likelihood exposure. greater loss individuals grasslands suggests risk local extinction.