Economic Reasons

Soil erosion and desertification may occur as a result of deforestation. These reduce a country's ability to grow crops and feed people.Non-sustainable use of resources such as timber will eventually lead to the collapse of the industry. Even if trees are replanted, the new forest will not be as biodiverse as the original one.Species of economic importance will become extinct if large scale destruction of habitats continues.Some undiscovered species may be medically useful.Continuous monoculture results in soil depletion and removal of nutrients from the soil. The soil eventually becomes infertile.High biodiversity provides protection from abiotic stresses such as extreme weather and natural disasters.In the Irish potato famine, the crops were damaged by the oomycete Phytophthora infestans. The low biodiversity meant no allele for resistance existed within the population.Some species have not been discovered and may in the future provide useful materials or medicines. The greater the biodiversity, the more species there are for future use.A diversity of wild species provides a large gene pool which is useful for cross-breeding with crop plants in order to increase characteristics such as disease resistance or yield.