Browsing All Posts filed under »feeding«

The net effect: caddis flies and streambed flow

March 26, 2022

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The beds of streams are dynamic interfaces where water, nutrients and living organisms move between surface and sub-surface environments, and streambed permeability has a significant influence on processes such as nitrogen cycling and organic matter decomposition.  Although the physics of streambed exchange are well understood, interactions between physical and biological processes have received relatively little […]

Invasive fish species take over in Singapore

December 14, 2021

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Cichlids make up a large family of freshwater fish with centres of native distribution in Africa and South America.  Cichlid species vary widely in terms of feeding habits, reproductive strategies and environmental tolerances, and their capacity for adaptive radiation in areas such as the African Great Lakes is legendary. Unfortunately, with human assistance many of them […]

In-stream wood increases fish abundance

September 28, 2021

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Although fallen woody material provides many freshwater fish species with essential habitat for feeding, refuge and spawning, a lot of submerged wood has been removed from rivers in an attempt to prevent floods and improve boat passage. However, current best management practice is to reverse this historical trend by reintroducing wood to rivers and streams.  […]

How flowing water affects the schooling of fish

September 28, 2021

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In many species of fish, individuals group together in shoals or schools to benefit from shared information – for example, on food availability or the presence of predators.  There’s also evidence that fish gain hydrodynamic benefits by taking up certain positions relative to other individuals, but not much is known about how flowing water affects […]

Wetlands are prime targets for herbivores

September 28, 2021

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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 […]

What do bioindicators really indicate?

June 7, 2021

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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 […]

How rivers regulate fish numbers

June 7, 2021

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Recruitment processes, which determine the number of young animals entering a  population each year, are central considerations in our attempts to understand fluctuations in abundance.  Although recruitment has been a key focus of fisheries scientists for many years, most of their work has involved marine fish species, and there’s been no fully integrated and comprehensive […]

Sound directions for the freshwater sciences

June 7, 2021

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A recent issue of the journal Freshwater Biology was devoted to the emerging field of ecoacoustics (the study of the ecological role of sounds), an exciting area with many applications in freshwater science.  So far, passive acoustic monitoring has been used mainly in terrestrial and marine environments, but recent studies reveal that inland waters support […]

Assessing plankton communities: coarse classification works well

March 13, 2021

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Information on the responses of ecological communities to environmental factors plays a significant role in the management of natural resources.  However, assessing the responses of some important groups, such as lake plankton, is often difficult because of a lack of taxonomic expertise.  A possible solution to this problem is to classify organisms by functional physiological, […]

Water abstraction changes local food chains

March 13, 2021

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The alteration of river flows by damming or extracting water is a major threat to freshwater ecosystems that can lead to habitat changes and local species extinctions.  While the impacts of dams and large-scale diversions have been the subject of many studies, the cumulative effects of small water abstractions aren’t so well understood, even though […]