【正文】
and mercial opportunities,such as first two of these groups have little or no negative impact on specific protected ,the former provide rather diffuse and generalized support,rarely linked to marginal electorates or practical second is relevant only for a limited number of protected areas,such as those associated with municipal water catchments. 。local ecosystem services such as drinking water supplies。t have gates:and if there are no rangers to stop them,people will continue to enter and exploit protected areas,legally or not. In addition,few parks agencies have a legal mandate to close parks to the public pletely,except in very unusual circumstances。t have enough money to manage their existing estate,let alone add to total area of national parks and similar reserves worldwide has continued to grow slowly,and funding for some protected are management agencies has increased significantly over recent ,on a global scale,public protected areas are increasingly short of the same time,they are subject to increasing human pressures,both from around outside their borders,and from increasing visitor numbers and a result,only the largest and most remote protected areas can simply be set aside to survive on their require continued management action to control ongoing conservation threats。 forests,woodlands and rangelands which are used for timber and livestock production but which none the less retain much of their original character function and biological diversity。s various ecosystems in a reasonably intact and functional state. This, of course, is the principal aim of the global system of protected areas, including World Heritage Areas, Biosphere Reserves, national parks and other conservation areas. However, on their own, parks are not enough to prevent continued loss of biological diversity: first, because they are too small and not fully representative。s