Climate change: Effect on sperm could hold key to species extinction

January 8, 2019 by Kris Sales, The Conversation

Since the 1980s, increasingly frequent and intense heatwaves have contributed to more deaths than any other extreme weather event. The fingerprints of extreme events and climate change are widespread in the natural world, where populations are showing stress responses.

A common fingerprint of a warmer world is a range shift, where the distribution of a species moves to higher altitudes or migrates toward the poles. A review of several hundred studies found an average shift of 17km poleward, and 11 metres upslope, every decade. However, if temperature changes are too intense or lead species to geographic dead ends, local extinctions occur in the heat.

In 2003, 80 percent of relevant studies found the fingerprints were seen among species, from grasses to trees and molluscs to mammals. Some migrated, some changed colour, some altered their bodies and some shifted their life cycle timings. A recent review of more than 100 studies found 8-50 percent of all species will be threatened by climate change as a result.

High temperatures and extinctions

Currently, we have a disturbingly limited knowledge of which biological traits are sensitive to climate change and therefore responsible for local extinctions. However, a potential candidate is male reproduction, because a range of medical and agricultural studies in warm blooded animals have shown that male infertility happens during heat stress.

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