Multiple stressors in freshwater ecosystems: biocides and climate change

Topics: Impacts and adaptation
Type: Briefing paper
Publication date: November 2018



Authors: Dr Michelle Jackson, Professor Nick VoulvoulisProfessor Guy Woodward

Man in a field spraying pesticides on the cropHuman activity is putting increasing pressure on our natural environment and human-induced impacts are becoming both more widespread and severe. This briefing paper considers how multiple threats to freshwater ecosystems interact with each other and provides recommendations on how to monitor, model and manage those threats effectively.


  • Human-induced environmental stressors, such as chemical pollution and climate change, are having increasingly widespread and severe impacts on biodiversity and natural resources.
  • These rarely occur in isolation, with ‘multiple stressors’ overlapping in time and space.
  • Freshwaters, such as lakes, rivers and ponds, which provide us with food, recreation, flood defences and other valuable ecosystem services, are influenced by stressors from many sources (e.g. industrial chemical spills, diffuse agrochemical pollution and ultimately global warming), and are particularly vulnerable.
  • The impact of multiple stressors is rarely simply the sum of their individual parts, with more complex interactions commonly occurring.
  • Stressors can interact with each other directly (e.g. by altering one another’s severity), or indirectly through altered species sensitivity, or via changes in species feeding relationships within the food web.
  • A new predictive framework is required for anticipating the combined impacts of stressors, and especially for biocides (e.g. pesticides and antibiotics) and climate change, which are both growing global threats.
  • A collaborative effort is needed to combine the knowledge of on-the-ground conservationists, academic researchers, and policymakers to create tools that can cope with the complexity of multiple stressors in natural systems.
  • An ecological networks approach could be used to detect both the immediate impacts of stressors (through the microbial community) and to predict responses across the wider ecosystem.

Download: BP 27 Multiple stressors in freshwater ecosystems: biocides and climate change [PDF]


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