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Long-term data show that climate change affects ecosystem functioning and the body size distributions of animal species, but more information is needed to understand the mechanisms underlying these changes. There’s a need for experimental studies that take account of linkages between the aquatic and terrestrial environment and that simulate changes in the intensity and frequency […]
October 8, 2018
Comments Off on Lakes are good for river species
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 […]
March 26, 2018
Comments Off on Why are there so many crocodiles in tropical waterholes?
Transfers of organic material from one aquatic environment to another (for example, through flood pulses or animal migrations) allow productive donor ecosystems to subsidise less productive habitats. However, there are big variations in the extent to which different animal species depend on production subsidies. To explore such differences, Australian researchers collected a wide array of […]
March 26, 2018
Comments Off on Freshwater fish surveys: direct observation works well
Although surveys of freshwater fish populations often rely on electrofishing, it’s difficult to use this technique in some habitats. An alternative sampling method is direct observation by snorkelling, an approach often applied in marine environments. While comparisons of the sampling efficiency of electrofishing and snorkelling have been carried out, most of them have been based […]
September 25, 2017
Comments Off on Predatory fish control prey populations – but not when the prey are other fish
Many lake studies have shown that predatory fish feeding on plankton or bottom-living invertebrates have a strong influence on the density, species composition and size structure of prey populations. Typically, there’s an inverse relationship between predator and prey populations, both in terms of density and in mean body size. However, there have been few reports […]
June 19, 2017
Comments Off on How the terrestrial landscape affects aquatic dispersal
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 […]
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 […]
October 8, 2018
Comments Off on Research on insect emergence warms up