Using fish guilds to assess community responses to temperature and flow regimes in unregulated and regulated Canadian rivers

摘要: Summary Hydropower currently accounts for 63% of Canada's total electricity generation and is bound to increase with the energy demands a growing population. With damming flow regulation known as major threats aquatic biodiversity river floodplain habitats, an improved understanding specific impacts needed proper management these systems. Although interactions among thermal regimes have been described in literature, their concurrent influence on fish guild responses has yet be analysed temperate rivers. Such analysis may used identify ecological traits linked variables reflecting regulation. Extensive field surveys were conducted across 25 unregulated regulated rivers estimate species density biomass. Fish models developed characterise morphologic, trophic, reproductive, habitat preferences behavioural traits, well phylogenetic associations. To ecologically relevant components rivers, we calculated indices based magnitude, frequency, duration, timing rate change each driver. Model relationships between biomass estimates then run using redundancy analyses (RDA) type dominant patterns variability. Variables representing magnitude summer temperatures intra-annual variability consistently selected independent drivers (>86% RDA models), clearly showing importance integrating current hydro-ecological studies. Fish significantly explained (R2Adj = 25–44%) predicted (R2CV = 35–76%) by characterising whereas not. trait–environmental performed better than those phylogeny. Our results also showed that describing trophic guilds had greatest explanatory power (R2Adj = 0.44 R2Adj = 0.41 respectively). This study identified differences trait–environment most susceptible changes temperature conditions resulting from regulation. In particular, more constant lower favoured over reproductive guilds. Our maintaining particular aspects regime important ensuring presence certain