How intensive use of water resources may stimulate water stress in freshwater ecosystems

Increasing human activities are likely to further exacerbate human-driven water stress (HDWS) on freshwater ecosystems. Activities like land-use change and population growth  can result in changes to natural flows patterns and water quality of river ecosystems. If left unmanaged, the effects of HDWS could potentially compromise human health and economic development.

To address potential changes in nutrients, microcontaminants, biological communities, and ecosystem functions that may occur because of HDWS, a meta-analysis of 44 relevant studies that compared the effects of human impacts at an upstream control site and downstream impacted site was conducted.

The meta-analysis, Effects of human-driven water stress on river ecosystems: a meta-analysis, found that:

  • HDWS has a wide range of impacts on the structure and function of river ecosystems that do not match those caused by naturally occurring water stress.
  • Flow regulation (aimed at supplying water for agricultural, urban and industrial processes) caused by dams resulted in the greatest impacts on water stress, with the uptake of water freshwater resources and channelization also being of significance.
  • HDWS led to a significant reduction in the abundance of biological communities and may have modified fish behaviour and feeding habits.
  • Regarding nutrient levels, it was found that pharmaceutical concentrations were roughly 8 times higher in impacted sites.
  • The scale of HDWS effects was also dependent on several external factors including time of year, rainfall, climate, and river size.

The meta-analysis found that HDWS led to a broad range of effects on the structure and function of river ecosystems that were not observed to occur naturally in other river systems. The authors suggest that addressing knowledge gaps, such as the consequences of HDWS on food webs and data on microbial organisms, are essential to forecasting future impacts of water stress on river ecosystems.

Written by Nathan Lay, MSDI Intern

The MSDI Evidence Review Service collaborates with McMaster University in Canada to curate the Social Systems Evidence, a freely accessible database of research evidence mapped to all of the Sustainable Development Goals.

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