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In forested headwater streams, detritus derived from decaying plant material is the primary source of energy driving the aquatic ecosystem, and most studies of such systems have focussed on the fate of leaf litter, the main resource. However, because the food quality of detritus is extremely low it’s unclear how headwater streams support their biological […]
July 5, 2018
Comments Off on How land plants control water plants
While terrestrial ecosystems rely on rainfall infiltration for their water supply, streamside ecosystems rely on the accumulation of surface and subsurface runoff in the riparian zone and the channel network. Rainfall that manages to percolate through the soil profile recharges aquifers, and these sustain streamflow and riparian and aquatic ecosystems during dry periods. Focussing on […]
July 5, 2018
Comments Off on How delayed is the flow-on effect?
It’s generally accepted that river flows have a major influence on the structure of stream communities, but what’s the lag time from river discharge to community expression? This question is particularly relevant for headwater streams that are vulnerable to seasonal drying or the over-extraction of groundwater, where changes in flow often lead to successional changes […]
July 5, 2018
There are concerns that human impacts on freshwater systems – particularly temperature increases linked to climate change and nutrient enrichment caused by run-off and pollution – are encouraging the spread of blue-green algae (cyanobacteria) capable of generating toxic blooms that threaten human and animal health. One such case is the recent spread of Cylindrospermopsis raciborskii, […]
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 conservation needs flagship umbrellas
Flagship species are surrogate species that are used to raise public awareness and funds for conservation, while umbrella species are those which ensure that a wide range of co-occurring species are conserved when they themselves are afforded protection. In principle, conservation efforts should be enhanced by identifying species – dubbed “flagship umbrellas” – that combine […]
March 25, 2018
Comments Off on How sedimentation affects the food web
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 […]
July 5, 2018
Comments Off on The magical diatom diet