We must make every effort to preserve, conserve, and manage biodiversity. Protected areas, from large wilderness reserves to small sites for particular species, and reserves for controlled uses, will all be part of this process. Such systems of protected areas must be managed to take account of a range of ecological and human-induced changes. This is no small task; yet humans must be equal to this challenge, or risk becoming irrelevant.
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Jump to: [Extent of Protected Areas] [Placement of Protected Lands] [Design of Nature Reserves] [Summary] [Suggested Readings]
Many species and ecosystems will disappear over the next century. However, starting with recognizing the problem, and then identifying management objectives, much can be done to alleviate this trend. A sound strategy would emphasize improving our management of existing protected land, and strategically adding new protected areas. Ecological systems have considerable potential to recover if appropriate restoration measures are taken. Ultimately we wish to manage populations and ecosystems sustainably, so that they may be utilized and enjoyed by future generations. These are the goals of science-based management.
Extent of Protected Areas
The World Resources Institute estimates that there are 8,163 protected areas worldwide, managed for various objectives ranging from strict nature protection to controlled harvesting. They cover 750 million hectares (1 hectare = 2.5 acres) of marine and terrestrial ecosystems, which is about 1.5% of the Earth's surface, and 5.1% of national land area. In many developing countries, the existence of protected areas creates conflicts for local people, who may depend upon that area for their subsistence. Often, enforcement of laws protecting parks is minimal.
The map below, created by the World Resources Institute, reflects the global variation in land protection.
Protection of biodiversity requires a network of reserves, including some large enough to protect many species and wide-ranging species, located where appropriate habitat exists, and protected from exploitation. Due to growing awareness, the amount of protected land is increasing. However, it is unlikely to ever exceed 6% of the Earth’s land surface, and even that amount may be optimistic. Nonetheless, parks and sanctuaries can be very effective, protecting a significant fraction of an area’s wildlife. Protected lands receive different levels of protection -- Some lands are highly protected as nature reserves, others as scenic areas, and still others provide for multiple use, including resource extraction.
Category I. Strict Protection: Sometimes called strict nature reserve/wilderness areas. Protected areas managed mainly for science or wilderness protection. Generally smaller areas where the preservation of important natural values with minimum human disturbance are emphasized.
Category II. Ecosystem Conservation and Tourism: Sometimes called national parks. Generally larger areas with a range of outstanding features and ecosystems that people may visit for education, recreation, and inspiration as long as they do not threaten the area's values.
Category III. Conservation of Natural Features: Sometimes called natural monuments. Similar to National Parks, but usually smaller areas protecting a single spectacular natural feature or historic site.
Category IV. Conservation Through Active Management: Sometimes called habitat and wildlife (species) management areas. Areas managed to protect and utilize wildlife species.
Category V. Landscape/Seascape Conservation and Recreation: Sometimes called protected landscapes/seascapes.
Category VI. Sustainable Use of Natural Ecosystems: Sometimes called managed resource protected areas. Protected areas managed mainly for the sustainable use of natural ecosystems.
The number of protected areas and their distribution among biogeographical regions is given in Table 1. Table 2 documents that new protected areas are being established around the world. Table 3 shows that protection of even a relatively small fraction of a nation's land area can be effective in protecting a substantial fraction of that nation's biological diversity.
Table 1. Number of Protected Areas and the Total Area of Various Biogeographical Regions They Cover
Placement of Protected Lands
Where to concentrate one's efforts is a critical issue facing conservation groups and government agencies. The uniqueness of an ecosystem, the number of species, especially endemic species (see GCI speciation lecture) it supports, and the imminence of the threats to its survival all play a role in the targeting of conservation activities. The World Wildlife Fund has identified 25 ecosystems around the world for highest priority (see locations on map below).
The size and placement of existing protected areas around the world are determined by many factors, and not necessarily primarily by conservation needs. Many are located in remote and unproductive lands, or in areas of great scenic beauty, or as a result of a conservation-minded national leader, philanthropist, or member of royalty. Some are in logged-over areas, and are only beginning to recover to their original splendor. A map of U.S. wilderness areas is a useful reminder that only a few percent of rivers and total land area, at most, are protected. In the U.S., there is more protected land in the West, partly due to its scenic beauty, but partly because much of this area is less productive.
At least until recently, the system of protected areas has been almost entirely haphazard. Gap analysis is a new approach based on mapping of vegetation, animals (usually terrestrial vertebrates) and land ownership in order to identify gaps in the network of parks, reserves, and public lands that hopefully protect the biodiversity they contain.
Gap analysis relies on three primary data layers. These are:
1. The distribution of actual vegetation types, delineated from satellite imagery:
2. The distribution of terrestrial vertebrates, predicted from the vegetation distribution by associating individual species with the vegetation that characterizes their habitat.
3. The distribution of land ownership:
The process can be as simple as placing layers of transparent mylar over a base map, such as a topo map, and tracing the information onto separate layers of transparencies. The first gap analysis looked at the distribution of three species of endangered Hawaiian honeycreepers (forest birds) on the island of Hawaii. It was possible to see the distribution of each bird species, and also locations where all three species coincided. Logically, these areas would be conservation priorities. Although the island had a number of nature reserves, none overlapped the birds’ distributions. These maps determined the site for a new reserve.
Extending this approach to a large scale depends on computer mapping of satellite images. Landsat TM (thematic mapper) or other remotely sensed imagery may be used to construct vegetation maps. Landsat TM receives seven spectral bands of reflected infrared light, in individual cells or pixels of 30m x 30m. Image classification uses those spectral data to develop a map of vegetation classes (see maps A and B above), which is compared to ground measurements to improve accuracy. The resulting vegetation map is geo-referenced, meaning that every location has a latitude and longitude or some other X-Y grid location.
Specialized computer software, along with these spatial data and other information, make up a Geographic Information System (GIS)
Using these data layers and a GIS, one can ask:
Design of Nature Reserves
Many factors influence the design as well as the placement of nature reserves. These include the specific habitat needs of species, the climate/soil/spatial requirements of ecosystems that one wishes to protect, and possible conflicts with human use of the target location. We will focus on some biological issues.
Reserves must be of sufficient size to maintain "large enough" populations of all "important species."
Reserves should also minimize edge and fragmentation effects.
Priorities for reserve management include:
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