Ecologists have determined that landscape edges—boundaries separating one type from another—have higher biological diversity and productivity than do the areas on either side of them. These transition zones are important to animals: mammals, birds, reptiles, insects, and fish. In terrestrial ecosystems edges are found between woodlands and grasslands and between forests and meadows. In aquatic ecosystems the edges are stream and river banks and pond and lake shores; the edges separating aquatic and terrestrial ecosystems are called riparian zones.