Invasive fish can cause ecosystem collapse •


Humans have introduced non-native species to ecosystems around the world. In a new study by Cambridge University, researchers found that specific animals such as silver carp and American crayfish cause other important species to decline in aquatic environments.

Experts report that these types of invasive fish can push lake ecosystems to a tipping point beyond which there is a sudden shift from healthy to degraded conditions. According to the researchers, this change is difficult to reverse.

The introduction of invasive fish leads to a decrease in water quality. When a freshwater ecosystem collapses and becomes unhealthy, it is often dominated by algae blooms. These blooms create toxins that poison freshwater supplies and block sunlight, destroying other life forms in a pond or lakes.

“Algal blooms represent one of the most significant threats to the security of the Earth’s surface freshwater,” said the study’s first author, Dr. Sam Reynolds. “Merely undoing the circumstances that triggered a tipping point will not restore the ecosystem – the road to recovery is slow and steep,”

While some invasive species can push a freshwater ecosystem towards collapse, other non-native species such as zebra mussels actually help block ecosystem collapse and can even restore degraded lakes.

“Managers of drinking water reservoirs, for example, can avoid the cost of treating harmful algal blooms, removing invasive crayfish while still allowing established non-native zebra mussels to remain and act as biological filters.” Said the study’s lead author. Professor Davis Aldridge.

“Early detection and rapid response plans should always be our first line of attack. But in situations where the invaders have already established themselves and can no longer be eradicated, it may be appropriate to embrace their positive effects. “

Although the research focuses on relatively shallow lake ecosystems, scientists believe the framework for their research could also be used for other ecosystems at risk of collapse.

The research is published in the journal Biology of global change.

Through Zach fitzner, Editor-in-chief


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