Browsing All Posts filed under »disturbance«

A lesson from fish: don’t let stress ruin procreation

March 26, 2022

Comments Off on A lesson from fish: don’t let stress ruin procreation

Annual fishes live in temporary ponds that dry out completely in summer.  As a result they have the shortest life spans of all vertebrates: after a few months they perish and the next generation depends on the survival of their drought-proof eggs, which hatch when the pond is eventually flooded.  As the shallow ponds dry […]

Lake management: are tipping points real?

December 14, 2021

Comments Off on Lake management: are tipping points real?

Freshwater biologists often seek to restore turbid shallow lakes dominated by phytoplankton to clear-water systems with a high abundance of submerged plants.  The usual plan of operation, which is often guided by lake ecosystem modelling, is to reduce external inputs of nutrients (e.g., from agricultural runoff or urban waste streams) to a threshold level at […]

Gene flow in complex river systems

December 14, 2021

Comments Off on Gene flow in complex river systems

Understanding how variations in habitat connectivity affect gene flow and possible genetic isolation in river systems is tricky because of the unique structural features of stream ecosystems, which are notoriously difficult to model: unlike terrestrial landscapes, they are linear branching networks, which means that overland distance is often a poor indicator of the correlation between […]

Guidelines for conserving groundwater ecosystems

December 14, 2021

Comments Off on Guidelines for conserving groundwater ecosystems

Aquatic groundwater-dependent ecosystems include subsurface aquifers, springs, seepage wetlands and other groundwater-fed surface waters.  Their biodiversity is high: for example, in Europe around 13% of all freshwater animal species are found only in groundwater.  Many of these species are rare, with limited distributions, and some are “living fossils”.  Groundwater species deliver ecosystem services by recycling […]

How to capture the tiniest animals

December 14, 2021

Comments Off on How to capture the tiniest animals

Although meiobenthic species are inconspicuous and the smallest animals living in aquatic sediments, they account for up to 80-90% of all animals in streams and lakes.  They play an important role in nutrient cycling, contribute up to half of all secondary production in freshwater food webs, and are good indicators of environmental pollution.  Meiofauna have […]

Land use patterns can aggravate toxic plankton blooms

September 28, 2021

Comments Off on Land use patterns can aggravate toxic plankton blooms

An understanding of how environmental factors affect the composition of biological communities is a crucial prerequisite for managing challenges due to climate change, land use practices and invasive species.  However, establishing the significance of interacting local and regional factors that vary widely across space and time is a challenge in itself.   Canadian biologists set out […]

Restoration of urban headwaters pays dividends

September 28, 2021

Comments Off on Restoration of urban headwaters pays dividends

Because urban streams are often ecologically degraded as a result of channelisation and pollution, restoration work is often attempted to improve ecosystem structure and function.  This usually involves remodelling of the stream channel.  Knowing that there are predictable shifts in ecosystem processes between headwater streams and the main body of the river, American ecologists investigated […]

Aquatic insects on the decline

September 28, 2021

Comments Off on Aquatic insects on the decline

Although there’s growing evidence that species in many animal groups, including insects, amphibians, aquatic invertebrates and birds, are experiencing dramatic and widespread declines in abundance, identifying the factors driving these changes is a major challenge because most ecosystems are affected by several stressors at the same time.  In addition, long-term data sets on species abundance […]

Earthquakes and groundwater

September 28, 2021

Comments Off on Earthquakes and groundwater

Studies have shown that earthquake activity can change the chemistry of nearby groundwater reserves – for example, strong increases in chlorides and sulphates in groundwater were recorded in the period before and after the Kobe earthquake of 1995.  Such changes can alter the communities of organisms living in the aquifer and lead to the extinction […]

Wetlands are prime targets for herbivores

September 28, 2021

Comments Off on Wetlands are prime targets for herbivores

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 […]