When human activity interferes with wildlife populations, a corridor is a way for separated populations to come together and breed. This will prevent a small population with a limited gene pool from occurring, leading to greater variation and a healthier population. When a road, farm, construction site, etc. becomes a barrier between wildlife, isolation among the members of a population could occur. Small groups become separated from the rest of the population and their gene pool becomes limited. If environmental conditions change, they may not have the genetic variations to adapt and the population could become extinct. Corridors provide a way to connect plants and animals within a habitat. An important corridor is the Siju-Rewak Corridor, in India, which protects elephants in the area. It joins the Rewak Reserve and the Siju Wildlife Sanctuary. It is believed that 20 percent of all the elephants in India live in this area as well as 139 other mammal species. This corridor is basically a biolink zone-- it allows for increased biodiversity which is healthier for the ecosystem.