Species loss, climate change linked

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GOTHENBERG, Sweden, Sept. 26 (UPI) -- Species loss and reduced biodiversity make nature more sensitive to climate change, Swedish researchers say.

This is especially true for species that sustain important functions such as water purification and crop pollination in a changing environment, they said.

Scientists at the University of Gothenberg say high biodiversity acts as an insurance policy as it increases the likelihood at least some species will be sufficiently resilient to sustain those important functions.

Experiments with eelgrass meadows in shallow inlets on the west coast of Sweden show climate change can exacerbate the negative effects of losing sensitive species, they said.

Eelgrass meadows in shallow inlets are important nursery habitats for cod, but eutrophication, the increase of nutrients in waters due to agricultural runoff, creates mats "nuisance" algae that shade and suffocate the eelgrass.

This leads to the loss of cod, which has resulted in a huge increase in numbers of smaller predatory fish. These fish, in turn, reduce the numbers of crustaceans that are effective grazers that normally control the algae.

This type of cascade effect has become increasingly common both onshore and off as many types of predator have been wiped out by hunting or fishing, researchers said, and could magnify the effects of global warming.

"Most management is based on the assumption that we [can] afford to lose the most sensitive species because other, more resilient species will take their place," researcher Johan Eklof said. "But this may not be the case with future climate changes, as it can reduce the net efficiency of the resilient species."

However, the researchers said, there is still hope if society decides to take action.

"If we protect the local biodiversity we still have, and restore the diversity we've lost, by for example protecting predatory fish stocks in coastal areas and reducing nutrient loading, then we'll probably be able to increase the ecosystems' resilience to climate change."