The study of the distribution and abundance of elements within landscapes, the origins of these elements, and their impacts on organisms and processes. A landscape may be thought of as a heterogeneous assemblage or mosaic of internally uniform elements or patches. Typically, landscape ecologists view the world as one would see it from an airplane (see illus.). At this scale, examples of patches include remnant blocks of forest, agricultural fields, and housing subdivisions. Many fields of study focus on large-scale patterns. For example, biogeographers, land-use planners, hydrologists, and ecosystem ecologists are concerned with patterns and processes at large scale. However, landscape ecologists bridge these disciplines in order to understand the interplay between the natural and human factors that influence the development of landscapes, and the impacts of landscape patterns on humans, other organisms, and the flows of materials and energy among patches. Much of landscape ecology is founded on the notion that many observations, such as the persistence of a small mammal population within a forest patch, may be fully understood only by accounting for regional as well as local factors.