Extinction: A Big (and Small) Problem, Part 2

Coyote skull (Canis latrans).

Last time we discussed the current 6th mass extinction of life on Earth and a few reasons as to why it’s happening. Today, let’s focus on who & what is affected by our rapidly changing world.

Loss of biodiversity, or the variety and number of species on the planet, is such a pressing issue that some biologists are studying patterns in animals that are becoming endangered (and going extinct) in an effort to predict how to conserve them before they’re beyond saving. A comprehensive study has shed light on how body size affects extinction risk in vertebrates.

The biggest and smallest animals are most at risk, with animals of intermediate size faring better (the “safest” size being 0.035 kilograms). This is because larger animals require more expansive habitats, which are rapidly dwindling worldwide, and take longer to reproduce & mature, meaning their populations are replenished at a slower rate. Small animals are generally restricted geographically and locally (their ranges don’t spread very far globally) and thus are more sensitive to catastrophic events such as natural disasters and continued habitat destruction.

The “safe zone” is pretty abstract, as extinction risk rises quite sharply towards either end of the spectrum, so what the study really highlights is how reliant living organisms are on quality habitat to survive. Data showing that bear populations have risen in the past 3 decades holds little relevance for future trends if currently living bears have less suitable space to live in than ever before. The battle against extinction will be a long one, and we must look towards the future if we are to be victorious!

Aaron Huelsman

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