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Coarse woody debris (CWD) derived from shoreline trees provides an important, spatially complex habitat and a food source for lake-dwelling organisms. Here are some interesting facts about lake CWD, taken from a recent review paper: In the absence of the physical action of flowing water, CWD breaks down more slowly in lakes than in streams. […]
June 19, 2017
Comments Off on A disturbing mix
The common carp (Cyprinus carpio) has been introduced to many locations around the world and is highly invasive. Its habit of foraging by digging in the bottom substrate significantly alters freshwater systems by uprooting plants, resuspending sediment, and increasing turbidity and the release of nutrients. However, the extent to which aquatic nutrient flows are affected […]
June 19, 2017
Comments Off on Erasing the boundaries
The new discipline of ecohydraulics considers the effects of water movement in aquatic ecosystems and blends ideas and techniques from aquatic ecology and engineering hydraulics. A central challenge for ecohydraulics is to reconcile differences between hydraulic engineers and ecologists in terms of the spatial and/or temporal scale of the processes that they tend to deal […]
June 19, 2017
Comments Off on Human impacts on ecological connectivity
Ecological connectivity – the exchange of organisms between habitat patches or subpopulations – has an influence on many key processes, including population dynamics, nutrient flux, disease transmission, species invasions, food-web interactions, genetic isolation and the maintenance of biodiversity. A recent study reviewed ways in which graph theory has been used to investigate how human activities […]
June 19, 2017
Comments Off on How big is a food patch?
Most studies of food patch choice by foraging animals have assumed that the patches in question are separate and well-defined. However, in many cases, predators feed in continuous habitats without obvious, discrete patches, and researchers are forced to choose an arbitrary spatial scale when calculating prey densities and interpreting the impacts of predators. An important […]
March 27, 2017
Comments Off on How fish negotiate culverts
While culverts are designed to facilitate the movement of water by allowing it to flow under roads or other obstructions, they can place physiological and/or behavioural restrictions on the movements of fish. Although several studies have considered the implications of culvert design for fish passage, surprisingly few have tried to identify the factors that influence […]
March 27, 2017
Comments Off on How fishing changes catchability
The bolder members of a fish population – often defined as those most willing to continue to forage under the threat of predation – tend to be relatively exploratory, aggressive, territorial, and enjoy higher rates of food intake and specific growth than more timid individuals. However, their larger size makes bold fish more vulnerable to […]
June 19, 2017
Comments Off on Coarse, shallow and wooden… but useful nonetheless