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In freshwater systems, drying events are ramp disturbances that reduce habitat availability and connectivity, while floods are sudden pulse disturbances. The relationship between disturbance and biodiversity is complex, and although some studies indicate that perennial rivers, which often flood, are more biodiverse than intermittent rivers, which periodically stop flowing and dry out, other work suggests […]
October 8, 2018
Comments Off on A clearer picture of suspended sediment
Because many pollutants adsorb onto the surfaces of fine sediment particles, sediment transport plays a central role in distributing contaminants throughout river systems. However, current models of sediment and pollutant transfer are complex and complicated by the fact that key processes such as adsorption, erosion and deposition aren’t easily observed. Belgian scientists have responded to […]
October 8, 2018
Comments Off on Lakes are good for river species
While it’s known that terrestrial landscape features, such as soil type, topography and land use, influence the abundance and distribution of stream fish, only a few studies have considered the possible effects of lakes on stream fish populations. Biologists carried out a three-year study on native brook trout (Salvelinus fontinalis) in 36 streams in the […]
July 5, 2018
Comments Off on How land plants control water plants
While terrestrial ecosystems rely on rainfall infiltration for their water supply, streamside ecosystems rely on the accumulation of surface and subsurface runoff in the riparian zone and the channel network. Rainfall that manages to percolate through the soil profile recharges aquifers, and these sustain streamflow and riparian and aquatic ecosystems during dry periods. Focussing on […]
July 5, 2018
Comments Off on How delayed is the flow-on effect?
It’s generally accepted that river flows have a major influence on the structure of stream communities, but what’s the lag time from river discharge to community expression? This question is particularly relevant for headwater streams that are vulnerable to seasonal drying or the over-extraction of groundwater, where changes in flow often lead to successional changes […]
September 25, 2017
Comments Off on Restoration and invertebrates: Build it and at least some of them will come
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 […]
September 25, 2017
Comments Off on Recognising uncertainty in hydro modelling
Because climate warming is thought to be a major cause of long-term shifts in storm runoff and the frequency of extreme floods and droughts, reliable projections of future hydrological changes are essential for the informed management of water resources. However, hydrological modelling involves dealing with a wide range of uncertainties, and so far these uncertainties […]
October 8, 2018
Comments Off on How does disturbance affect biodiversity?