ABSTRACT
Habitats come in all shapes and sizes, occupying the full sweep of geographical scales. They range from small (microhabitats), through medium (mesohabitats) and large (macrohabitats), to very large (megahabitats). Microhabitats are a few square centimetres to a few square metres in area (Table 2.1). They include leaves, the soil, lake bottoms, sandy beaches, talus slopes, walls, river banks, and paths. Mesohabitats have areas up to about 10,000 km2; that is, a 100×100 kilometre square, which is about the size of Cheshire, England. Each main mesohabitat is influenced by the same regional climate, by similar features of geomorphology and soils, and by a similar
set of disturbance regimes. Deciduous woodland, caves, and streams are examples. Macrohabitats have areas up to about 1,000,000 km2, which is about the size of Ireland. Megahabitats are regions more than 1,000,000 km2 in extent. They include continents and the entire land surface of the Earth.
