Grazing zebras help fatten cattle
Rearing cattle alongside wildlife can help herds thrive, contrary to popular belief, a study in Kenya has found.
It is commonly thought that wild animals compete with cattle for food, leading ranchers to separate them, reports Science.
To test this theory a team of Kenyan and US scientists conducted a field experiment in Kenya. They fenced off pastures in a local savannah into two sections: cattle-only and cattle and wildlife. In the dry season, cattle sharing land with wildlife lost weight. But in rainy seasons, they fattened up much more than their isolated counterparts.
The effect seems to be because of zebras, the team reports. Thanks to their specialised digestive systems they eat the grasses that other herbivores avoid, possibly exposing richer vegetation below for other animals, such as cattle.
Wilfred Odadi, a rangeland ecologist at the Mpala Research Centre, Kenya, told Science: "The hoof print was obvious even to the naked eye. You would see that [the grassland] is greener and leafier, especially after it had started raining."
Norman Owen-Smith, an ecologist at the University of Witwatersrand, South Africa, said the findings are "of wide, practical importance".
According to Johan du Toit, an ecologist at Utah State University, United States, natural selection has favoured a mix of herbivores living together on pastures. He added that changing ranchers' minds on wildlife would be tough, but possible if scientists and policymakers could communicate the potential economic benefits.
Science 333, 6050 (2011)