Carbon Sinks and Rhinos:
What are Carbon Sinks?
A carbon sink is whatever absorbs more carbon than it emits. Forests, soils, oceans, and the atmosphere store carbon and carbon moves between them in a cyclical fashion. At various times, forests act as sources (releasing more carbon than is absorbed) or sinks.
Fossil carbon is usually static. Carbon in the atmosphere or biosphere can be released, for example, by forest fires, insect outbreaks, decay, logging, or the decline of forest ecosystems, an effect of climate change. (SOURCE: FERN)
So why could the extinction of rhinos be catastrophic?
Rhinos, a mega-herbivore, are a keystone species who play an important role in ecosystems. Rhino grazing helps maintain savanna grasslands, which in turn supports numerous other species. Where there are more rhinos, researchers have discovered, there is greater biodiversity of plants and animals. Researchers have recently explained that not only do grasslands provide food for many species, but like the savannas, they play an essential global role. They act as natural carbon sinks: storage lockers for carbon dioxide in the atmosphere. If rhinos go extinct, it could spell disaster for African savannas—and ultimately for the whole planet.
In the 21st century, Africa’s carbon emissions will increase as industrialization progresses. The savannas where rhinos live are important ecosystems, and preservation of the species is essential in maintaining them (reported in Business Insider, Christina Sterbenz Oct 20/14).
So rhinos are important landscape engineers. They can drastically shift vegetation composition and structure through their feeding behavior. White rhinos can graze grass to a short stubble and maintain large patches of grazing lawns which influence not only fluxes of nutrients and productivity in savanna grasslands, but also the rate at which fire spreads in the landscape mosaic.
Some species may have such a significant role that they may cause an ecosystem to acquire new characteristics. (A recent example is the wolves of Yellowstone.)
Trophic downgrading may impact processes as disparate as the dynamics of disease, wildfire, carbon sequestration, invasive species, and biochemical cycling.
Large herbivores have major impacts on vegetation when plentiful. For example, the effects of elephants on trees, or of white rhino on grasses. An extraordinary change resulted from an increase in wildebeest population when disease was eradicated: reduced plant biomass and thus wildfires changed the Serengeti ecosystem from carbon source to carbon sink.
(From Key Topics in Conservation Biology 2: David W Macdonald and Kathleen J Willis.)
Photo courtesy of Princess Tilly, Wikipedia.