Browsing All Posts filed under »predation«

Lakes are good for river species

October 8, 2018

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While it’s known that terrestrial landscape features, such as soil type, topography and land use, influence the abundance and distribution of stream fish, only a few studies have considered the possible effects of lakes on stream fish populations.  Biologists carried out a three-year study on native brook trout (Salvelinus fontinalis) in 36 streams in the […]

Embryos learn about future predators

July 5, 2018

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Because anti-predator strategies are highly adaptive, many prey species have evolved the ability to assess future predation risk and respond accordingly.  It’s been discovered that this capacity extends to embryos, which can use environmental cues, such as odours from predators and injured fellow prey, to learn about predators that will pose a threat for them […]

How sedimentation affects the food web

March 25, 2018

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In rivers and streams, high predator densities are predicted to boost algal biomass by reducing the number of grazing animals. However, in disturbed systems the smothering of stream bed surfaces by sediment is expected to have an opposite, negative effect on algal biomass.  Studies that investigate interactions between sedimentation (an abiotic stress factor) and predation […]

Benefits and costs of habitat complexity

December 21, 2017

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The fact that biodiversity tends to be higher in structurally complex habitats suggests that, on balance, the fitness-related advantages of habitat complexity outweigh the disadvantages.  Possible advantages include a greater supply of locations where animals can hide from predators and conserve their energy, and higher abundances of potential prey.  Also, in complex habitats less energy […]

Size and survival in tadpoles  

December 21, 2017

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  Because interactions between predator and prey species are usually size-dependent, their ecological impacts are affected by variations in body size within predator and /or prey populations.  However, there’s been little research on the ways that such variation affects animal communities.   Using tadpoles of the brown frog (Rana pirica) as model prey and larvae of […]

Once more from the top

December 21, 2017

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Top-down trophic cascades are population-level effects transmitted along food chains, from consumers down to primary producers.  In a typical three-level food chain the loss of top predators (for example, as a result of human exploitation) allows herbivore populations to increase, which in turn reduces populations of algae or higher plants.   However, few studies have considered […]

Mosquitofish threaten frogs

September 25, 2017

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The mosquitofish, Gambusia holbrooki, is one of the most invasive freshwater fish species in the world.  Although it’s been widely introduced for mosquito control, it has a broad diet that includes algae, higher plants, detritus, invertebrates and fish.  As a result, the species has negative predatory and competitive effects on native fish.   Although declines in […]