5 years ago

Forest Restoration in Landscapes

Forest Restoration in Landscapes

18 N. Dudley is likely,

18 N. Dudley is likely, and where these thresholds are known they can play a key role in monitoring impacts and planning restoration strategies. Impacts on authenticity or naturalness: On an ecosystem scale, measuring impacts on overall naturalness of forests is easier than surveying biodiversity and acts as a partial surrogate; generally the greater the naturalness of a forest, the more of its original constituent species are likely to survive. Worldwide forest authenticity is declining fast. In most West European countries less than 1 percent of forests are classified by the United Nations as “undisturbed.” 21 A growing proportion of forests in Africa, the Pacific, and the Amazon have been logged at least once. Ecological integrity: This concept covers many of the above issues. It is defined by Parks Canada as “a condition that is determined to be characteristic of its natural region and likely to persist, including abiotic components and the composition and abundance of native species and biological communities, rates of change, and supporting processes.” 22 Evaluation of options for restoration should also consider the reasons why forest loss or degradation have occurred. Many restoration programmes fail because the pressures that caused deforestation are not addressed, and restored forests suffer the same fate as the original forests. If population or economic pressures mean that there is insufficient fuelwood, then planted trees will be burned long before they have a chance to mature and reach a useful size. On the other hand, understanding the nature of the pressures and working with local communities to plan restoration in ways that are mutually beneficial increases the chances of restoration succeeding. Assessment needs to address several different aspects: • Impacts of forest loss and degradation on biodiversity, naturalness, and ecological integrity; • Some of the key factors causing change; • Changes in biodiversity, naturalness, and ecological integrity following restoration interventions. 21 UNECE and FAO, 2000. 22 Parks Canada, undated. Whilst the first two can be assessed through single surveys, assessment of trends implies the need for a monitoring system. 2. Examples 2.1. New Caledonia In New Caledonia the overall loss of forests creates a critical threat to biodiversity and ecological integrity. Today only 2 percent of the dry forest remains in the island, in scattered fragments of 300 hectares or less, leading to extreme threats to the remaining biodiversity. Over half of the 117 dry forest plant species assessed by the IUCN Species Survival Commission are threatened, and it is likely that several have already gone extinct. For example, the tree Pittosporum tanianum was discovered in 1988 on Leprédour Island in an area that has been devastated by introduced rabbits and deer, declared extinct in 1994, and rediscovered in 2002.This level of damage suggests an urgent need for both restoration of forest cover and a carefully designed series of interventions to protect and allow the spread of species that may already be at critically low levels. 23 2.2. Western Europe Changes in management and human disturbance have reduced near-natural forests to less than 1 percent of their original area in most western European countries, despite an expanding forest estate. In Europe as a whole, almost nine million hectares are defined as “undisturbed by man,” but most of this exists in the Russian Federation and Scandinavia; Sweden records 16 percent of its forest as natural, Finland 5 percent, and Norway 2 percent. In most of Europe the proportion is usually from zero to less than 1 percent; for instance, Switzerland records 0.6 percent. 24 Even in forest-rich countries like Finland and Sweden, many forestd-welling species are threatened because the forests contain only a proportion of the 23 Vallauri and Géraux, 2004. 24 UNECE and FAO, 2000.

expected habitats and ecosystem functions. Here the challenge is less to recover forest area (although this may sometimes be important) than to restore natural ecosystem processes and microhabitats. Specific monitoring criteria are needed and these have started to be developed, for instance by the Ministerial Conference on the Protection of Forests in Europe. 25 2.3. Brazilian Atlantic Forests In the Atlantic forest of Brazil, forest loss and fragmentation are combining to threaten endemic species. Although international attention tends to focus on threats to the Amazon, the Atlantic forests of Brazil have undergone far more dramatic losses. The forests have already been reduced to just 7 percent of their original size, and the associated threats to biodiversity are increased because the remaining areas are fragmented and the populations are genetically isolated. The area is home to many endemic species, including some of the 19 resident primates and 92 percent of amphibian species found there. Attention has focussed particularly on the golden lion tamarins (Leontopithecus rosalia), which now inhabit less than 2 percent of their original range.Their population is currently around 1000, up from little more than 200 twenty years ago following a major conservation effort. However, population is still believed to be below long-term viability, and subpopulations are isolated in remaining forest fragments. Restoration efforts, therefore, focus particularly in reconnecting the remaining forest fragments of high biological importance. 2.4. Uganda In Uganda loss of connectivity is separating populations of mountain gorillas even in areas with relatively high forest cover. The world’s remaining mountain gorillas (Gorilla beringei beringei) live in isolated rain forests in the mountains on the borders of Uganda, Rwanda, and the Democratic Republic of Congo, with half of the world’s known population, 350 indi- 25 Ministerial Conference on the Protection of Forests in Europe, 2002. 3. Impact of Forest Loss and Degradation on Biodiversity 19 viduals, in Bwindi Impenetrable Forest Reserve in Uganda. Another major population is in the Virunga volcanoes area, some of which is in Mgahinga National Park. Neither of these populations is considered large enough to be genetically secure over time, but both reserves are also thought to be reaching their natural carrying capacity. Linking the two populations is important for their long-term survival, but the intervening land has all been converted to agriculture, and any restoration efforts will need a long period of planning and negotiation (information from park staff in Bwindi). Understanding of what has been lost, and what is at risk of being lost, should be the basis for any forest restoration that has biodiversity conservation amongst its aims. This needs to be augmented with an understanding of what type or quality of forest is needed to maintain biodiversity. If the key issue is connectivity for large mammals and birds, for example, managed secondary forests or even plantations or shadegrown coffee may be suitable. If the threats are more generally to forest biodiversity, restoration efforts should probably be aimed at creating a forest as near to natural as possible. 3. Outline of Tools Detailed biodiversity surveys are expensive and rely on a high level of expertise. Methodologies for achieving these have become increasingly sophisticated, and a number of short cuts have been developed where time and money are limited. 3.1. National Level Surveys National level surveys can help identify the scale of the problems and the locations of valuable remaining forest habitat, which should usually serve as the starting point for restoration efforts. The U.N. Economic Commission for Europe and the Food and Agriculture Organisation asked countries to report on the proportion of their forest that was “undisturbed by man,” taken here to mean left without management interventions for at least 200 years. This has created a fairly crude but effective

Forest Landscape Restoration - IUCN
Landscape restoration