Habitat complexity and species diversity in rivers

摘要: 1. Rivers are highly structured ecosystems in which habitat complexity and heterogeneity postulated to affect species diversity abundance. However, the exact links between structure organisms such as macro-invertebrates remain poorly understood. 2. Field surveys at patch reach scale were combined with a field experiment Wye Usk, Wales, to: i) quantify variations among habitats river sections, ii) assess their influence on macro-invertebrates, iii) separate ecological effects of confounding physical factors iv) determine whether type promote nestedness assemblages. 3. At scale, surface but not increased macro-invertebrate diversity, richness abundance independently area, only when was ignored. Surface minor determinants types. 4. A involving baskets containing cobbles, pebbles, gravel or 50:50 mixtures revealed that flow explained significant richness, composition, appeared filter based body size. interstitial volume had no effect, implying differences assemblages mineral may result from flow-related effects. 5. Macro-invertebrate occurring some habitats, typically lower trait be nested sub-sets those organic habitats. Nested reduced altered representation. River sections fewer supported abundance, weakly heterogeneous sections. 6. Habitat concluded have consistently weak scales studied. In contrast, affected assemblage structure, traits, important implications for management conservation.