Biodiversity-Rich Ecoregions in Africa Need Protection
Ashbindu Singh, Bhaskar Ramachandran, Gene Fosnight, Sean Chenoweth, and Tom Crawford
"Attack what can be overcome" - The Art of War, Sun Tzu
Biological diversity, the variety and variability among living organisms and the environment in which they occur, is important to maintain life-sustaining systems of the biosphere, yet is threatened by many human activities. Recently the Global Biodiversity Assessment of the United Nations Environment Programme (UNEP) concluded that the adverse effects of human impacts on biodiversity are increasing dramatically and threatening the very foundation of sustainable development. The total number of species that inhabit the planet is unknown and it is believed that many extinctions will occur even before they have been named and described. It is estimated that 85-90 percent of all species can be protected by setting aside areas of high biodiversity before they are further degraded, without having to inventory species individually. It is generally assumed that most terrestrial species are found in the tropics. Realistically, only a relatively small portion of the total land area is likely to be devoted to biodiversity conservation; hence, it is critical to geographically identify areas rich in species diversity, unprotected species diversity and endemism (species native or confined to a particular area) as a first step toward the protection of remaining natural habitats before they are destroyed.
Figure 1: Comparison of land cover classes and protected areas
In the past, protected areas often have been set aside without regard to the biodiversity within their boundaries. As a result, many protected areas have little significance in terms of biodiversity, and conversely, many areas of habitat with significant biodiversity lack protection. This study seeks to identify relationships between land cover, human population, and protected areas by analyzing comprehensive and consistent spatial data sets of 1-km resolution to answer the following questions:
° Are African ecoregions with significant biodiversity adequately protected?
° Is biodiversity within Africa threatened by human population pressure and land use?
Areas analyzed include the following:
° The African continent (figs. 1 and 4).
° The African Great Lakes Region (figs. 2 and 3).
Protected Areas of Africa
Protected areas in Africa occupy slightly over 2 million sq km or 7% of the continent‚s 30 million sq km (figs.1 and 4). Among various ecoregions, barren and sparsely vegetated lands comprise about 9.6 million sq km whereas biodiversity-rich tropical evergreen broadleaf forests comprise about 3 million sq km. Of the barren and sparsely vegetated lands, about 4 percent are protected. Closed shrublands, which are estimated to be over 700,000 sq km in extent, have the largest proportion of protected area, approximately 14 per cent. About 2 million sq km, or about 8 per cent, of croplands and a mosaic of croplands mixed with natural vegetation are under protected status. Even when the protected proportion appears substantial, they may not be well distributed. For example, large areas of drier regions are protected in Algeria, whereas many other unique and fragile drier ecosystems in northern Africa are not protected.
Protected Areas in the African Great Lakes Region
The ten-country African Great Lakes region contains a wide range of habitats, including deserts, savannas, and dry and humid tropical forests (fig. 2). In this region of 6 million sq km, 12 percent of the area is protected. Biodiversity-rich tropical evergreen broadleaf forests cover approximately 1.4 million sq km of the region, and about 100,000 sq km, or slightly over than 7 percent, of these forests are protected, leaving the bulk of the tropical evergreen broadleaf forest unprotected. In contrast, protected areas comprise about 9 to 15 per cent of the areas falling under the category of woody savannas, savannas, grasslands, croplands, and croplands/natural vegetation mosaic.
Furthermore, the degree to which the forests listed as protected are actually protected varies. In the African Great Lakes Region, for example, about 125,000 sq km of croplands and croplands interspersed with natural vegetation mosaic are found in protected areas. The apparent encroachment of agriculture into protected areas highlights the lack of enforcement for protection of the natural flora and fauna in the region.
Figure 2. African Great Lakes Region: Comparison of land cover classes and protected areas
Population Density and Protected Areas of the African Great Lakes Region
The highest human population densities are found in Rwanda, Burundi, and Uganda around Lake Victoria and in scattered areas in Malawi, Zambia, and Kenya (fig. 3). Of importance is the identification of areas with high population density and their proximity to protected areas. Unless vigorously enforced, protection of these areas is in jeopardy. Significantly many protected areas are associated with the high population densities in the highlands of Uganda, Rwanda, Burundi, and Kenya that are under immediate threat. Many larger protected areas in the Congo, Zambia, and Tanzania are associated with areas of lower population density.
Figure 3. African Great Lakes Region: Comparison of population density and protected areas
Summary for Policy makers
The geographic analysis of relationships between protected areas and distribution of land cover types and population density clearly revealed the following facts:
° Lack of (1) protection status and (2) effective implementation of protection measures in the designated protected areas seems to pose a serious threat to forest biodiversity in Africa.
° This study using geographic information system techniques estimates that approximately 7 percent (2 million sq km) of the total land area of Africa is protected; this figure is based on measuring the spatial extent of protected areas provided by the World Conservation Monitoring Centre (WCMC). This is substantially more than the estimate of approximately 5 percent (1.5 million sq km), compiled from official statistics, again from the WCMC, which is normally cited in international publications. This discrepency highlights the need for better environmental information infrastructures in countries to generate and maintain accurate and up-to-date environmental data for planning and policy formulation purposes.
° About 6 percent of the area covered by biodiversity-rich tropical evergreen broadleaf forests in Africa is protected. The majority of these valuable ecoregions, rich in biodiversity and endemic species, are concentrated in countries like the Democratic Republic of Congo and Madagascar, which desperately need more protection. So practical action programs that include accelerated expansion of protected area networks are urgently needed.
° In Africa, drier ecoregions have more protected area than tropical evergreen broadleaf forests. This is contrary to the widely held belief that moist habitats, such as tropical rain forests, are generally better protected than drier zones, such as dry forests and grasslands. Unfortunately, even for the drier ecoregions, the protected areas are not well distributed.
° In most of Africa, the opportunity still exists for pro-active measures to conserve biodiversity. Low human population densities in many areas provide an opportunity to protect such areas for conservation purposes if action is taken now.
° The presence of croplands in legally protected areas is an indicator that biodiversity cannot easily be preserved in the face of human competition for the same land. To ensure the preservation of biodiversity, and of endemic and endangered species, protected status must be accompanied by effective long-term enforcement measures. More effort should be made to understand the socioeconomic factors associated with the protection of biodiversity; local stakeholders must have a role and economic incentives to conserve biodiversity.
° A shift in national and international policy formulation and planning processes, based on targeting biodiversity-rich areas, is needed to protect biodiversity more effectively in Africa. Geographic targeting and programmatic focus are both needed to conserve ecoregions rich in biodiversity and endemism, plus address the socioeconomic causes of encroachment and subsequent loss of biodiversity.
The analysis was carried out using geographic information system and remote sensing technologies with comprehensive and consistent 1-km spatial data sets. The land cover data set was derived from the International Geosphere-Biosphere Program Land Cover Classification based on the National Oceanic Atmospheric Administration 1-km Advanced Very High Resolution Radiometer (AVHRR) satellite data spanning a 12-month period (April 1992 Ų March 1993) and produced by the Land Cover Characterization team at the U.S. Geological Survey‚s (USGS) EROS Data Center. The political boundary data are from the Digital Chart of the World. Also used in the analysis were the protected areas database from the WCMC‚s and Center for International Forestry Research (1997) and the Population Density Database for Africa from UNEP‚s Global Resource Information Database.
Some of the smaller protected areas may not have been accounted for owing to the coarse resolution of analysis. The protected areas database my not be current for all countries. Where information is not available for the exact extent of a protected area, a point has been inserted representing the center of the site. Polygons were made for such locations by using the area information in the textual databases and drawing a circular polygon of the relevant area around the point location of the site. The land cover and population were the best available data sets covering all of Africa. Considerable regional errors are known to exist in the mapped distribution of croplands. Even so, substantial encroachment of cropland into protected areas is detected, although quantitative estimates for any one protected area are most likely to be unreliable.
The population data set is generated using a model incorporating many variables, including the location of protected areas; hence, the areas of intersection between population and protected areas are compromised. This does not invalidate conclusions drawn from the analysis of the proximity of the protected areas to the areas of high population density. None of these data sets have been rigorously validated, so local relationships and distributions should be viewed with caution. Availability of high-quality, current data remains a stubborn barrier in such analytical analysis, highlighting the need to support the development and updating of such database.
The views expressed in this text do not necessarily reflect those of the agencies cooperating in this project. The designations used and material presented above do not imply the expression of any opinion whatsoever on the part of the cooperating agencies concerning the legal status of any country, territory, city, or area or of its authorities, or of the delineation of its frontiers or boundaries.
The authors are grateful to a number of scientists, including Gray Tappan, Brad Reed, Eric Wood, Jim Rowland, Robb Campbell, and Steve Howard (EROS Data Center), Mike Scot (USGS), and Anna Stabrawa (UNEP), who all reviewed the manuscript and made valuable suggestions. All remaining omissions and errors rest solely with the authors.
This analysis was carried out within the framework of the UNEP Global Environmental Outlook (GEO2) report.
For further information please contact
Dr. Ashbindu Singh, Regional Coordinator
UNEP Environment Information and Assessment Programme-
North America, EROS Data Center, Sioux Falls, SD 57198;
Tel : 605-594-6107/6117;
Cooperating agencies: UNEP, NASA, USGS, University of Maryland, and University of California at Santa Barbara