Browsing All Posts filed under »connectivity«

How fish negotiate culverts

March 27, 2017

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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 […]

Floating times of riparian seeds

March 27, 2017

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Given the important role that the transport of water-borne seeds plays in the long-distance dispersal of riparian plants, surprisingly little is known about this process.   In laboratory experiments, a team of Australian and Chinese scientists measured the floating times of seeds collected from sixty species of Australian riparian plant species. Most species reached the test […]

Factoring history into threat assessments

December 13, 2016

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Genetic variation allows populations to adapt to environmental changes, and it’s often the case that threatened species exhibit low genetic diversity. Human-produced habitat fragmentation is a well-recognised cause of genetic bottlenecks, but the additional effects of larger-scale biogeographic factors are rarely considered. As an example of such biogeographic impacts, populations that have managed to survive […]

How river transport affects dissolved organic matter

December 13, 2016

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In most rivers, the downstream transport of dissolved organic matter (DOM) makes large amounts of energy available to aquatic ecosystems. The River Continuum Concept (RCC) of Vannote et al. (1980) provided a useful framework for studying the influence of organic material from headwater streams on the structure and function of downstream ecosystems. The RCC hypothesized […]

How environmentally-damaging are run-of-river hydropower systems?

June 1, 2016

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Hydropower generation typically involves the creation of large dams for the storage and release of water, which can have serious adverse effects on riverine environments. However, growing pressures on governments to meet renewable energy targets have stimulated interest in small-scale hydropower systems, especially run-of-river schemes, which use the flow within a river channel and operate […]

Cutting reed beds while protecting bird diversity

December 18, 2015

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The common reed (Phragmites australis) occurs throughout the world and provides habitat for a wide range of animal species, including a number of reedbed specialists. Although reeds are commonly cut for commercial reasons and to prevent plant succession to wet woodland, it’s been shown that large-scale cutting can reduce the feeding and breeding success of […]

Inequity creates a water crisis

December 18, 2015

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Lake Urmia, in western Iran, is a Ramsar-listed Biosphere Reserve and one of the world’s most significant salt lakes. Until recent times it had a length of 140 km. However, its size has been reduced by 90% as a result of forest destruction and short-sighted water policies. A recently-published case study of Lake Urmia offers […]