Excessive inflows of nutrients, especially phosphorus in fertilisers, pesticides and sewage, reduce water quality in lakes and reservoirs and can encourage toxic algal blooms, often with serious implications for public health, food security and biodiversity. Increases in nutrient inputs are partly due to increased rainfall associated with climate change. And the availability and residence times […]
March 26, 2022
Comments Off on A lesson from fish: don’t let stress ruin procreation
Annual fishes live in temporary ponds that dry out completely in summer. As a result they have the shortest life spans of all vertebrates: after a few months they perish and the next generation depends on the survival of their drought-proof eggs, which hatch when the pond is eventually flooded. As the shallow ponds dry […]
December 14, 2021
Comments Off on Lake management: are tipping points real?
Freshwater biologists often seek to restore turbid shallow lakes dominated by phytoplankton to clear-water systems with a high abundance of submerged plants. The usual plan of operation, which is often guided by lake ecosystem modelling, is to reduce external inputs of nutrients (e.g., from agricultural runoff or urban waste streams) to a threshold level at […]
September 28, 2021
Comments Off on Wetlands are prime targets for herbivores
Although studies of herbivory in freshwater ecosystems have focussed mainly on the grazing of algae, recent findings have shown that, by reducing macrophyte abundance, invertebrate herbivores can have a significant impact on the structure and function of freshwater communities. In fact, on average they remove around 45% of the plant biomass in freshwater ecosystems, compared […]
June 7, 2021
Comments Off on What do bioindicators really indicate?
There have been many attempts to find environmental measures that can be used as reliable indicators of disturbance in freshwater ecosystems, and proposed measures are often based on features of fish and macroinvertebrate communities, such as species richness, diversity, feeding styles and life history patterns. While such metrics should ideally be robust enough for general […]
December 16, 2020
Comments Off on Ecosystem impacts of invasive carp
The common carp (Cyprinus carpio) is one of the world’s most widespread invasive fish species and has a reputation for causing ecological damage. It’s thought that the excretion of nutrients by dense populations of carp stimulates algal growth, which increases turbidity, and that the feeding and spawning activities of carp further increase turbidity by bringing […]
September 26, 2020
Comments Off on A clever way to rebalance a lake
Lakes are often subject to high-nutrient inflows from agricultural runoff, industry and wastewater treatment, and these inputs lead to algal blooms, reduced biodiversity and a shift from clear to turbid water. Such lakes can be remediated by reducing nutrient loads or by biomanipulation, where fish are selectively removed to lower predation pressure on zooplankton, which […]
June 25, 2020
Comments Off on How birds use Amazonian lakes
In the Amazon, most ecological studies have focussed on forest environments and data on freshwater biodiversity are relatively scant, even though vast areas of the catchment are flooded for several months each year. In the largest ecological study of Amazonian waterbird communities to date, the dependence of birds on the physical and spatial features of […]
March 26, 2022
Comments Off on Lake management gets harder as the climate changes