Colonisation, emigration and equilibrium of stream invertebrates in patchy habitats

摘要: 1. Understanding of the ecology stream assemblages is enhanced by quantifying colonisation and dispersal rates, but these are difficult to measure at small scales. Using field-located artificial streams that mirrored natural patches habitat, we investigated immigration, emigration stability invertebrates on leaf-litter packs over 38 days. 2. We fitted equilibrium "drift-out" models immigration data. Overall individuals (plateau similar Day 12) taxa (total 50; plateau 21 24) was rapid curvilinear towards a stable asymptote, suggesting saturation equilibrium. 3. Abundant early colonists, mainly several chironomid species, dictated shape curve, patterns varied among species. Thus, plateaux were due successional shift in composition rather than simple equilibrium. 4. The model total numbers taxa, individual gradual not lacking constant immigration. 5. High turnover rarer taxa. assemblage maintained drift-mediated compensating for lost through emigration, emergence or mortality. 6. masking effect few substantial accumulation important considerations regarding time. Rapid provides denuded substrata downstream.