Browsing All Posts filed under »ponds«

A lesson from fish: don’t let stress ruin procreation

March 26, 2022

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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 […]

How big should samples of aquatic vegetation be?

December 14, 2021

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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 […]

Biodiversity offsets: compliance doesn’t guarantee ecosystem function

March 13, 2021

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When human activities impair habitats and reduce biodiversity, environmental offsets, such as the creation of new wetlands and the planting of native vegetation, can help to preserve ecosystem function and services.  However, the success of offsetting projects depends on the extent to which the required measures are complied with, and compliance is often poor.  This […]

Are there more species in permanent waters?

December 16, 2020

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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, […]

Life between the sand grains

September 22, 2019

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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, […]

Constructed wetlands can be traps for wildlife

March 30, 2019

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  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 […]

Recognising the biodiversity value of ponds

January 14, 2019

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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 […]

Worms, midges and the greenhouse effect

July 5, 2018

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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 […]

Triggers for algal blooms: peak temperatures aren’t always important

July 5, 2018

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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, […]

Collapsing waterweeds:  shading and herbivory work together

December 21, 2017

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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 […]