biodiversity

A measure of biological variation, whether represented by genes, species, habitats or ecosystems (gene pool, species diversity, habitat diversity or ecosystem diversity). Human environmental impact has reduced habitat and ecosystem diversity, for instance by clearing forest and draining wetland, increasing the rate of species extinction above the natural rate and causing population loss in many other species.

This definition is abridged from A – Z of tree terms: A companion to British arboriculture.
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