Browsing All Posts filed under »biodiversity«

The magical diatom diet

July 5, 2018

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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 […]

Surveying river birds

July 5, 2018

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River birds are effective ecological indicators because they’re linked to river and riparian food webs in many  ways and are easily observed.  Boat-based surveys of river birds pose disturbance issues and can be difficult during periods of high or low flow, while transect-based surveys can be compromised by lack of access to private land.  Researchers […]

Why are there so many crocodiles in tropical waterholes?

March 26, 2018

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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 […]

Freshwater fish surveys: direct observation works well

March 26, 2018

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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 […]

Freshwater conservation needs flagship umbrellas

March 26, 2018

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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 […]

Helping to resolve the plankton paradox

March 26, 2018

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The richness of plant plankton communities in natural ponds and small lakes is very high – typically up to about 80 species at any one time in most systems. However, ecological theory predicts that the number of coexisting species should be no greater than the number of limiting resources, and normally in the case of […]

Restoration and invertebrates: Build it and at least some of them will come

September 25, 2017

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It’s commonly assumed that the biodiversity of a disturbed ecosystem can be improved by restoring its original physical and chemical conditions. According to this “Field of Dreams” view (“build it and they will come”), ecosystem recovery occurs through the recolonization activities of lost species.  While a lot of river restoration is founded on Field of […]