Wright Justin P, Jones Clive G, Flecker Alexander S
Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA.
Institute of Ecosystem Studies, Millbrook, NY, 12545, USA.
Oecologia. 2002 Jun;132(1):96-101. doi: 10.1007/s00442-002-0929-1. Epub 2002 Jun 1.
Ecosystem engineering - the physical modification of habitats by organisms - has been proposed as an important mechanism for maintaining high species richness at the landscape scale by increasing habitat heterogeneity. Dams built by beaver (Castor canadensis) dramatically alter riparian landscapes throughout much of North America. In the central Adirondacks, New York, USA, ecosystem engineering by beaver leads to the formation of extensive wetland habitat capable of supporting herbaceous plant species not found elsewhere in the riparian zone. We show that by increasing habitat heterogeneity, beaver increase the number of species of herbaceous plants in the riparian zone by over 33% at a scale that encompasses both beaver-modified patches and patches with no history of beaver occupation. We suggest that ecosystem engineers will increase species richness at the landscape scale whenever there are species present in a landscape that are restricted to engineered habitats during at least some stages of their life cycle.
生态系统工程——生物体对栖息地的物理改造——已被提出是通过增加栖息地异质性在景观尺度上维持高物种丰富度的重要机制。海狸（加拿大海狸）建造的水坝极大地改变了北美大部分地区的河岸景观。在美国纽约州阿迪朗达克山脉中部，海狸进行的生态系统工程导致形成了广阔的湿地栖息地，能够支持河岸带其他地方没有的草本植物物种。我们表明，通过增加栖息地异质性，海狸在包括海狸改造斑块和无海狸占据历史的斑块的尺度上，使河岸带草本植物物种数量增加了33%以上。我们认为，只要景观中有在其生命周期至少某些阶段局限于工程化栖息地的物种，生态系统工程师就会在景观尺度上增加物种丰富度。
