Definition

A habitat is the place where a plant or animal naturally lives, its home, providing the food, water, shelter, and space it needs, so a frog's habitat is a pond with water to swim in and insects to eat, while a woodpecker's is a forest with trees to nest in; when a habitat is destroyed, its animals cannot simply move next door, since a neighbor's habitat is usually already full. More precisely, a habitat is the specific environment an organism or population lives in, defined by physical conditions such as temperature, moisture, and soil or water type, and biological resources such as food, shelter, and mates, and because a single ecosystem contains many habitats, habitat loss, fragmentation, and degradation are the leading causes of species decline; habitat is the address, while niche, the organism's role within it, is the job. At a quantitative level, habitat quality varies continuously and determines local population growth, producing source populations with a surplus and sink populations with a deficit linked by dispersal in a metapopulation, and species-area relationships ($S = cA^z$, with $z$ typically $0.2$ to $0.35$) predict that shrinking habitat area reduces the number of species it can support, with fragmentation adding edge effects and isolation beyond the effect of area alone.