Browsing All Posts filed under »ecosystems«

How fire affects stream communities

March 30, 2019

0

  By removing riparian vegetation, wildfires can have significant effects on river ecology, especially in headwater systems where fringing plant life helps to regulate stream temperature and provides a source of carbon in the form of leaf litter and woody debris.  To help understand the impacts of fire on streams, and the length of time […]

Getting river history right

March 30, 2019

0

  Information on past climate patterns can prove invaluable when assessing the responses of freshwater ecosystems to environmental change, but what are the implications for ecological understanding if beliefs about climate history are incorrect?  This question has been explored by scientists who used the Murray River, Australia’s largest river system, as a case study.  Hydrologically, […]

How rivers befriend seabirds

January 14, 2019

Comments Off on How rivers befriend seabirds

Where rivers flow into the ocean, the density fronts between fresh and salt water masses help to concentrate zooplankton and larval fish, making them more available to predators.  For example, freshwater discharge from the Columbia River creates a large brackish plume that can stretch for hundreds of kilometres along the North American coast, and nutrient […]

Floodplain fisheries and overexploitation

October 8, 2018

Comments Off on Floodplain fisheries and overexploitation

The floodplain fishery in the Pantanal region of South America, one of the biggest wetlands in the world,  illustrates the difficulties often faced in managing resources in complex, highly changeable environments.  In the late 1970s and early 1980s, traditional small-scale commercial fishers accounted for around three-quarters of the fish catch.  In the absence of scientific […]

How sedimentation affects the food web

March 25, 2018

Comments Off on How sedimentation affects the food web

In rivers and streams, high predator densities are predicted to boost algal biomass by reducing the number of grazing animals. However, in disturbed systems the smothering of stream bed surfaces by sediment is expected to have an opposite, negative effect on algal biomass.  Studies that investigate interactions between sedimentation (an abiotic stress factor) and predation […]

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

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 […]

Restoration and invertebrates: Reappraising stream condition indicators

September 25, 2017

Comments Off on Restoration and invertebrates: Reappraising stream condition indicators

In degraded rivers and stream systems, the replanting of riparian vegetation is a common restoration activity, partly because increases in shading, nutrient interception and litter fall are expected to provide food and habitat benefits for aquatic communities. Changed habitat conditions should be reflected in indices of stream condition, such as those based on macroinvertebrate richness. […]