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 How big should samples of aquatic vegetation be?
When sampling aquatic vegetation what plot size should you use? Ideally, the aim should be to choose the smallest area in which the species in the plant community in question are adequately represented – in graphical terms, this is when the curve of the number of species plotted against sample area flattens out. For terrestrial […]
December 16, 2020
Comments Off on Are there more species in permanent waters?
How important is the influence of permanent water on the biodiversity of lakes, ponds and wetlands? Because many freshwater habitats dry out on a regular basis, to survive under such conditions organisms need to be able to exist as terrestrial adults or dormant stages, or to migrate to more permanent water bodies. Despite these challenges, […]
September 22, 2019
Comments Off on Life between the sand grains
Meiofauna are among the smallest creatures in existence, being defined as animals 44-500 microns in size. They live in bottom sediments, where sand grains are “home” and a few square centimetres are “regions”. They are a diverse group and include members of a number of phyla. Although they’re an important part of aquatic food chains, […]
March 30, 2019
Comments Off on Constructed wetlands can be traps for wildlife
In urban areas, natural wetlands are rapidly being replaced by constructed wetlands designed to treat stormwater. While stormwater wetlands provide habitats for wildlife, there are concerns that their often high concentrations of nutrients, heavy metals and pesticides may have a harmful impact on animals that are attracted to them – in other words, that […]
January 14, 2019
Comments Off on Recognising the biodiversity value of ponds
Although pond habitats have been relatively neglected by conservationists, several studies have shown that ponds can contribute more to regional biodiversity than running waters. Because they are isolated, small in size and often poorly protected by conservation programmes, pond ecosystems are highly vulnerable to environmental threats such as those presented by urbanisation. To help provide […]
July 5, 2018
Comments Off on Worms, midges and the greenhouse effect
Severely impacted aquatic environments such as urban wetlands and wastewater treatment ponds are designed to treat large amounts of carbon and nitrogen, which raises concerns about their potential greenhouse gas emissions. Because pollution-tolerant worms (oligochaetes) and insects (midges) can reach very high densities in such systems, it’s possible that their activities influence the flux of […]
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, […]
December 21, 2017
Comments Off on Collapsing waterweeds: shading and herbivory work together
In lakes and ponds, aquatic plants help to maintain clear-water conditions and their decline can cause a shift to a turbid state with lower biodiversity. But what triggers the collapse of waterweed populations? Grazing by aquatic herbivores would seem to be an obvious cause, but supporting evidence for this idea has proved surprisingly elusive, leading […]
March 26, 2022
Comments Off on A lesson from fish: don’t let stress ruin procreation