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Habitat fragmentation is the process whereby a large continous area of habitat is both reduced in area and divided into two or more fragments. When habitat is destroyed, a patchwork of habitat fragments may be left behind. These fragments are often isolated from one another by highly modified or degraded landscape, and their edges experience an altered set of conditions, referred to as the edge effect.
Habittat fragments differ from the original habitat in three important ways:
(1) Fragments have more edge effect – greater exposure to edge effect
(2) Center of fragments closer to the edge
(3) Fragments have smaller and sometimes isolated populations, which were formerly continuous habitats with large populations
Fragmentation limits dispersal and colonization, restrict access to food and mates, and divide existing widespread population. The smaller subpopulations are then more vulnerable to inbreeding depression, genetic drift, etc. A road and its parking loops block the movement of a forest-dwelling beetle species, effectively creating two subpopulations.
The major edge effects result into microclimate changes. For instance, a forest which has been fragmented will have less shade (an ecosystem service the tree/canopy provides). This will increase the temperature in the group floor, and moisture will be long, less humid and at night, the floor will be much colder.
Increased incidence of fire – increased wind, lower humidity, and higher temperatures make fires more likely. For instance, in forest fragments where wood has accumulated on the edge can become dry and burn.
Interspecies interaction: Fragmentation increases the vulnerability of the fragments to invasion of exotic and native species since the forest edge is a high-energy, high-nutrient, disturbed environment.
Potential for disease. Habitat fragmentation put wilds populations of animals in closer proximity to domestic animals.
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