定義： A habitat of rolling or flat terrain where grasses predominate. Typically, what is called a meadow has more biodiversity than a grassland as the former contains not only grasses but a significant variety of annual, biennial and perennial plants.
定義： This organism produces this material or substance, either during its life or after death. A produces B if some process that occurs in A has output B.
定義： A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
