Browsing All Posts filed under »connectivity«

Human impacts on ecological connectivity

June 19, 2017

0

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 […]

How the terrestrial landscape affects aquatic dispersal

June 19, 2017

0

How does the surrounding terrestrial landscape affect the dispersal of pond-dwelling organisms? Although some studies suggest that small aquatic crustaceans can disperse efficiently across a range of intervening environments, other work has pointed to dispersal limitation, especially over large distances.  Czech researchers examined the passive dispersal of microcrustaceans (cladocerans, copepods, and ostracods) by comparing communities […]

How fish negotiate culverts

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 […]

Floating times of riparian seeds

March 27, 2017

Comments Off on Floating times of riparian seeds

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

Comments Off on Factoring history into threat assessments

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

Comments Off on How river transport affects dissolved organic matter

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

Comments Off on How environmentally-damaging are run-of-river hydropower systems?

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 […]