Studying the Relationships Between Large Wildlife and the Global Carbon Cycle
The exact nature of the relationship between large, charismatic wildlife species and the comparatively invisible carbon compounds that cycle around an ecosystem is not abundantly clear. As far as ecosystem carbon goes, it’s understood that the tiny microorganisms in soil do a lot of work, breaking down carbon compounds and releasing carbon dioxide by respiring. Another direct and intuitive process is that plants draw carbon back down from the atmosphere through photosynthesis. This complementary cycle is already well-documented and, in fact, the idea that microbes and plants form the biological crux of the world’s carbon cycle is long-established. While they are undeniably key players, it would be too easy to ascribe all the credit for biological carbon dynamics to only plants and tiny organisms.
It is increasingly clear that in order to better understand ecosystem and global carbon dynamics, we need to consider the ways in which large wildlife directly and indirectly impact them. Large wildlife can directly influence an ecosystem’s available carbon by, for example, consuming vast quantities in the form of both plant and animal matter.
They can also have indirect impacts. For one, large carnivores can control the number of large herbivores snacking on an ecosystem’s plant life by preying upon them; for another, the next logical step after consuming carbon is, ahem, depositing the result (dung) into the environment in large payouts, a source of nutrients both rich and essential for many photosynthesizing (and therefore carbon-dioxide consuming) organisms. For example, whale feces is circulated around the ocean and to its surface via upwelling in a process called the ‘whale pump’, where it stimulates primary production.
Daniel Tiveau