ProjectEffects of winter water level drawdown on the biodiversity and abundance of macroinvertebrates in temperate lakes
Freshwater ecosystems are amongst the world’s most valuable and vulnerable natural resources and are exposed to many anthropogenic pressures. Winter water level drawdown is one of the pressures of greatest concern in reservoirs and is known to have multiple effects on macroinvertebrates and fishes in temperate lakes. For example, it kills macroinvertebrates, the primary prey resource for many species and age classes of fish, by exposing them to desiccation and freezing and also greatly reducing the amount of available habitat. Our research design is to conduct a comparative survey of regional lakes including the Grand Lac St. François (GLSF), a large lake in southern Quebec whose water level is highly regulated by the Jules-Allard dam. By comparing responses across regional lakes that are similar in chemistry and morphometry, but vary substantially in water level, our goal is to quantify relationships between diversity and/or abundance of macroinvertebrates and the level of water drawdown.