Animals, the Keepers of Natural Climate Change Solutions?
What does your favorite wild animal, a wildebeest, a wolf and a sea otter have in common? Among many similarities, these and other wild animals affect the carbon cycle. And in case you need another reason to appreciate wild animals more, scientists suggest that animal effects on the carbon cycle could lead to natural solutions that might slow climate change.
All herbivorous (plant-eating), carnivorous (meat-eating) and frugivorous (seed-eating and dispersing) animals in land or marine environments directly and indirectly affect ecosystems through behaviors and biological processes, such as eating, breathing, excreting and roaming around landscapes. These zoogeochemical effects impact the carbon cycle and how carbon is used, stored, and exchanged across land and seascapes.
This point is precisely what makes Utah State University watershed science and ecology professor Trisha Atwood and her colleague’s new scientific review so significant. Current Earth system models use remote-sensing technology to predict future climate change and what it will look like on Earth. While these models show how carbon transfers from soil reserves to plants through photosynthesis and respiration, “surprisingly, they don’t account for animals at all,” says Atwood. “Earth system models can be inaccurate because they are missing part of the story.”
Carbon (C) is an essential, abundant element that is continuously circling in the Earth’s system. It is stored in and makes up the basic building blocks of soils, plants and animals—including humans. Plants take up C from soil reserves, and release it through photosynthesis and respiration. Herbivorous animals consume plants and carnivorous animals prey on herbivores and then release C they don’t store as respiration or waste. Carbon in animal waste returns to the soil for microbial decomposition and storage, which is then used again for uptake by plants. In respiration, carbon combines with other elements to form molecules or greenhouse gases. Carbon dioxide (CO2) and methane (CH4) gases exist in our atmosphere, trapping heat on the Earth’s surface that enables plant, animal, and human life on Earth. Animals are an obvious contributor and mediator in the carbon cycle but to what extent?
Atwood and her colleague’s note that limitations from past technology and the complex movements of wild animals across sea and landscapes have kept scientist from fully understanding and including the impact of animals on the carbon cycle. They reviewed several marine and land animal studies that demonstrate how small studies in real and artificial systems have worked to show animal carbon use and storage at a local, small scale; however, Atwood declares, “if we really want to get this information, we need to go bigger.”
Fortunately, Atwood and colleagues outline and call future researchers to design studies using new LIDAR (Light Detection and Ranging) remote-sensing technology combined with spatial ecosystem mapping and direct on the ground animal studies. Together, this technology and research could show a more nuanced view of how sea and land animals mediate carbon between the atmosphere and across sea and landscapes and suggest how to manage land and marine spaces and animals for healthy carbon cycling and storage.
