The wildebeest has a huge impact on the ecosystems of the Serengeti. By consuming large amounts of grass, wildebeests create more room for trees to grow—trees which provide food sources and shelter for other animals, like giraffes and birds. As they migrate across the Serengeti, wildebeests also leave behind vast amounts of dung, which acts as a natural fertiliser for the landscapes. The carcasses of the wildebeests that die during their travels also fertilise the land and provide food sources for a wide variety of animals, including crocodiles and fish. Their decaying bodies add approximately 13 US tonnes of phosphorus, 25 tonnes of nitrogen, and 107 tonnes of carbon (12, 23, and 97 metric tonnes, respectively) each year to the land, contributing to its health and fertility.