Ecological studies to assess environmental impacts to seagrass species or habitats are often undertaken. However, they must be designed carefully and often entail sampling diverse metrics to estimate the health of species and the entire meadow community. Some examples of impacts are given by Thayer et al. (1975) and Phillips (1984). Sampling design issues and metrics for such studies are addressed later in this chapter.
b. Identification
Identification of seagrasses and their associated plants and animals can sometimes be performed in the field , but new species cen be encountered and samples are often required to provide a type specimen. A multitude of floras ( Frodin 1984 ), invertebrate lists and field guides exist for specific regions, but the wide variety of plants and animals inhabiting seagrass beds can make identification difficult. There are two major texts that describe seagrass species worldwide ( den Hartog 1970, Phillips andeñez 1988 ).