Fluctuating fortunes: Stressor synchronicity and fluctuating intensity influence biological impacts

Fluctuating stressors can hurt ecosystems more

31 March 2023

The effect of human activities on ecosystems can be magnified by fluctuations in stressors.

Natural ecosystems around the world are increasingly coming under pressure due to human-generated stressors such as pollution and physical disturbance. These stressors generally go up and down with time, but most assessments of human activities on ecosystems just consider constant stressors.

Now, four researchers from Griffith University in Australia have evaluated the effect of fluctuations in two stressors on seagrass — a vulnerable ecosystem that is in decline around the world.

They subjected seagrass to five different patterns of reduced light and herbicide. When the two stressors fluctuated out of sync with each other, the biomass of seagrass was more than a third lower than when the two stressors were constant.

This result highlights the need to take the timing of stressors into account when assessing environmental impact.

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References

1. Ecology Letters 25, 2611–2623 (2022). doi: 10.1111/ele.14120