Browsing All Posts filed under »mammals«

Freshwater megafauna under threat

March 26, 2022

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Because large-bodied animal species tend to have a higher than average extinction risk, there are concerns that freshwater megafauna (species with body weights over 30 kg) are relatively vulnerable to human-induced disturbances such as reduced river flows, habitat fragmentation and pollution.  In the 40 years leading up to 2012, global populations of freshwater megafauna declined […]

Dams challenge platypus populations

March 26, 2022

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The construction of dams has many adverse effects on river hydrology and ecology.  Dams limit animal movements and reduce the cover of riparian vegetation, which leads to bank erosion and the filling of stream pools with sediment.  Dam-related impacts have been documented for many types of riverine animals, including macroinvertebrates, amphibians and waterbirds.  However, the […]

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 […]

Wolves and cougars change the ecology of streams

June 25, 2020

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Streamside plant communities can be very biodiverse and productive and provide habitat and food for a wide range of aquatic and terrestrial organisms.  They also protect river banks and intercept suspended sediment during floods.  Changes to riparian vegetation can have a great influence on the structure of food chains and the shape of stream channels.  […]

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 […]

How the terrestrial landscape affects aquatic dispersal

June 19, 2017

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How does the surrounding terrestrial landscape affect the dispersal of pond-dwelling organisms? Although some studies suggest that small aquatic crustaceans can disperse efficiently across a range of intervening environments, other work has pointed to dispersal limitation, especially over large distances.  Czech researchers examined the passive dispersal of microcrustaceans (cladocerans, copepods, and ostracods) by comparing communities […]

Stream restoration can keep invasive trout at bay

December 16, 2014

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River restoration aims to build sustainable populations of native aquatic species by enhancing habitats and eliminating invasive species. However, because it can be difficult or impossible to remove exotic species once they’re established, stream managers often concentrate on assisting native species to coexist with invaders. So how successful is habitat enhancement as a way of […]

Control of water plants by large grazers

July 2, 2014

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While studies have shown that the establishment and survival of aquatic plants are strongly influenced by abiotic conditions, the potential impacts of grazing on freshwater macrophytes have been somewhat neglected. Working in ten nature reserves in the Netherlands, researchers compared the survival and growth of two macrophyte species in experimental 3 x 6m plots at […]

Low flows trap river dolphins

December 28, 2013

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Large-scale flow regulation, irrigation and power-generation projects pose serious threats to river biodiversity.  In India, the widespread construction of dams and barrages has reduced dry-season flows to the point where animal populations are becoming severely fragmented or are already locally extinct.  Threatened forms include charismatic species such as the Ganges river dolphin  ( Platanista gangetica […]

Deer, climate and pathogen risk

September 21, 2011

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An understanding of landscape-scale flows can be crucial when attempting to assess how the risks of water pollution vary with environmental conditions.  In mountainous regions, drinking water supplies for dispersed human populations usually receive only limited pre-treatment.  However, such areas often support large populations of warm-blooded  animals which have the capacity to contaminate water bodies […]