Analysis by an international team of researchers of more than 100 studies comparing wildlife in forests that had been modified with those that had not confirms the crucial role that virgin forests play in conserving the natural world. The researchers conclude in the journal Nature that, “When it comes to maintaining tropical biodiversity, there is no substitute for primary forests.”

The worldwide meta-study found that most species, notably birds, do much better in virgin tracts than in areas that have been cleared for agriculture, plantations or agro-forestry or selectively logged for certain types of trees. In all but the latter, the overall impact on biodiversity was marked. In all cases, the variety of plants and animals was depleted more severely than the sheer number of organisms present.

Surprisingly, total mammal populations may do better under some kinds of forest modification, although this may be because opportunistic animals such as rats multiply even as the diversity of mammals drops. Birds, insects and plants experience an unequivocal loss.

The study addresses how best to specifically preserve nature across the tropics, where most human population growth and rapid development is occurring. It compares the effects of “land-sharing”, where farming and other development enables wildlife to share the same space, and “land-sparing”, which provides entitlement areas to wildlife while humans use other segments as intensely as they like.

Source: BBC News