In order to conserve biodiversity, it is essential to know what species are present in a country, province or area, and exactly where they occur. It is also crucial to know the name of species because this allows access to information about whether the species is threatened, rare, or of special cultural or biological significance. For many animals, only a specialist can provide this information. These specialists are called taxonomists. They not only identify and describe new species that they discover but also go on expeditions to survey areas that we know little about. Many taxonomists are also biogeographers: they plot the distribution of different species, identify patterns of distribution and the processes that determine these distributions (e.g. temperature, altitude and vegetation) using GIS, and identify areas of special importance for conservation. Taxonomists and biogeographers often work in museums, but they can also be employed in conservation agencies and universities.