Conservation: Forests, Grasslands, Parks, and Nature Reserves Chapter 6 Conservation: Forests, Grasslands, Parks, and Nature Reserves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

WORLD FORESTS The forest ecosystem produces valuable materials, such as lumber paper pulp, and domestic livestock, that are important in human culture. They also play vital roles in regulating climate, controlling water runoff, providing wildlife habitat, purifying the air, and providing a host of other ecological services. These terrestrial biomes have scenic, cultural, and historic values that deserve to be protected.

Forests and grasslands together occupy almost 60 percent of global land cover. These ecosystems provide many of our essential resources. They also provide essential ecological services.

Boreal and tropical forests are most abundant Old-growth forests are those that cover a large enough area and have been undisturbed by human activities long enough that trees can live out a natural life cycle. Some of the world’s most biologically diverse regions are undergoing rapid deforestation, including Southeast Asia and Central America. Forests are a huge carbon sink, storing some 422 billion metric tons of carbon in standing biomass. Forest contribute towards rainfall: cutting forests could change patterns of rainfall

Forest Products Wood plays a part in more activities of the modern economy than does any other commodity. There is hardly any industry that does not use wood or wood products somewhere in its manufacturing and marketing processes. Total annual world consumption is about 3.7 billion metric tons, or about 3.7 billion m3. The United States, Russia and Canada are the largest producers of wood. More than half of the people in the world depend on fire-wood or charcoal as their principal source of heating and cooking fuel.

Forests provide many valuable products Wood plays a part in more activities of the modern economy than does any other commodity. International trade in wood and wood products amounts to more than $100 billion each year. Developed countries produce less than half of all industrial wood but account for about 80 % of its consumption. Less-developed countries, mainly in the tropics, produce more than half of all industrial wood but use only 20 %.

Tropical forests Some of the richest and most diverse terrestrial ecosystems on the earth are tropical forests. Diminishing forests There is considerable debate about current rates of deforestation in the tropics. Remote sensing experts calculate that 3 million ha per year are now being cut and burned in the Amazon basin alone. There are different definitions of deforestation. Some scientists insist that it means a complete change from forest to agriculture, urban areas, or desert. Others include any area that has been logged, even if the cut was selective and regrowth will be rapid.

Tropical forests are being cleared rapidly Causes of deforestation Tropical forests are among the richest and most diverse terrestrial systems. Although they now occupy less than 10 percent of the earth’s land surface, these forests are thought to contain more than two-thirds of all higher plant biomass and at least half of all the plant, animal, and microbial species in the world. A century ago, an estimated 12.5 million km2 of tropical lands were covered with closed-canopy forest. This was an area larger than the entire United States. The FAO estimates that about 9.2 million ha, or about 0.6 percent, of the remaining tropical forest is cleared each year (fig. 6.6).

Causes of Deforestation A variety of factors contribute to deforestation: - Expansion of shifting cultivation into undisturbed areas. - Intensification of agriculture in shifting cultivation areas. - Conversion to small-scale permanent agriculture. - Conversion to large-scale permanent agriculture.

Forest protection About 12 percent of all world forests are in some form of protected status, but the effectiveness of that protection varies greatly. Costa Rica has one of the best plans for forest guardianship in the world. Attempts are being made there not only to rehabilitate the land (make an area useful to humans) but also to restore the ecosystems to naturally occurring associations.

Debt-for-nature swaps Banks, governments, and lending institutions now hold nearly $1 trillion in loans to developing countries. There is little prospect of ever collecting much of this debt, and banks are often willing to sell bonds at a steep discount—perhaps as little as 10 cents on the dollar. Conservation organizations buy debt obligations on the secondary market at a discount and then offer to cancel the debt if the debtor country agrees to protect or restore an area of biological importance. E.g., Conservation International, for instance, bought $650,000 of Bolivia’s debt for $100,000—an 85 percent discount. In exchange for canceling this debt, Bolivia agreed to protect nearly 1 million ha (2.47 million acres) around the Beni Biosphere Reserve in the Andean foothills

Temperate forests also are at risk Many endemic species, such as the northern spotted owl, are so highly adapted to the unique conditions of these ancient forests that they live nowhere else. Less than 10 percent of old-growth forest in the United States remains intact.

Harvest methods Most lumber and pulpwood in the United States and Canada currently are harvested by clear-cutting, in which every tree in a given area is cut, regardless of size. This method is effective for producing even-age stands of sun-loving species such as pines, but often increases soil erosion and eliminates habitat for many forest species when carried out on large blocks. Some alternatives to clear-cutting include shelterwood harvesting, in which mature trees are removed in series of two or more cuts, and strip-cutting, in which all the trees in a narrow corridor are harvested. The least disruptive harvest method is selective cutting, in which only a small percentage of the mature trees are taken in each 10- or 20-year rotation.

Harvest methods Most lumber and pulpwood in the United States and Canada currently are harvested by clear-cutting, in which every tree in a given area is cut, regardless of size.

Ecosystem Management Ecosystem management attempts to integrate sustainable ecological, economic, and social goals in a unified, systems approach. Some of the principles of this philosophy include: Managing across whole landscapes, watersheds, or regions over ecological time scales. Considering human needs and promoting sustainable economic development and communities. Maintaining biological diversity and essential ecosystem processes. Utilizing cooperative institutional arrangements. Generating meaningful stakeholder and public involvement and facilitating collective decision making. Adapting management over time, based on conscious experimentation and routine monitoring.

Ecosystem management Ecosystem management is an U.S. Forest Service policy that attempts to integrate sustainable ecological, economic, and social goals in a unified, systems approach.

GRASSLANDS Grasslands, chaparral, and open woodlands are attractive for human occupation, so they frequently are converted to cropland, urban areas, or other human-dominated landscapes. Worldwide the rate of grassland disturbance each year is three times that of tropical forest. Desertification is the process of conversion of once fertile land to desert.

RANGELANDS After forests, grasslands are among the biomes most heavily used by humans. Because grasslands, chaparral, and open woodlands are attractive for human occupation, they frequently are converted to cropland, urban areas, or other human-dominated landscapes. Range Management By carefully monitoring the numbers of animals and the condition of the range, ranchers and pastoralists (people who live by herding animals) can adjust to variations in rainfall, seasonal plant conditions, and nutritional quality of forage to keep livestock healthy and avoid overusing any particular area.

Overgrazing Overgrazed rangeland Lightly grazed pasture 19

Conscientious management can actually improve the quality of the range. When grazing lands are abused by overgrazing – especially in arid areas – rain runs off quickly before it can soak into the soil to nourish plants or replenish groundwater. The process of conversion of once fertile land to desert is called desertification. Overgrazing is responsible for vegetation degradation and soil erosion.

Overgrazing threatens many rangelands

Overgrazing in USA As in many countries, the health of most public grazing lands in USA is not good. Political and economic pressures encourage managers to increase grazing allotments beyond the carrying capacity of the range. Lack of enforcement of existing regulations and limited funds for range improvement have resulted in overgrazing, damage to vegetation and soil including loss of native forage species and erosion. The Natural Resources Defense Council claims that only 30 percent of public range-lands are in fair condition, and 55 percent are poor or very poor (fig. 6.15). On the other hand, ranchers defend their way of life as an important part of western culture and history. Although few cattle go directly to market from their ranches, they produce almost all the beef calves subsequently shipped to feedlots. And without a viable ranch economy, they claim, even more of the western landscape would be subdivided into small ranchettes to the detriment of both wildlife and environmental quality.

Some biomes are relatively unprotected. Figure 6.20 shows a comparison between the percent of each major biome in protected status. Not surprisingly, there’s an inverse relationship between the percentage converted to human use (and where people live) and the percentage protected. Temperate grasslands and savannas (such as the American Midwest) and Mediterranean woodlands and scrub (such as the French Riviera or the coast of southern California) are highly domesticated, and, therefore, expensive to set aside in large areas. Temperate conifer forests (think of Siberia, or Canada’s vast expanse of boreal forest) are relatively uninhabited, and therefore easy to put into some protected category.

PARKS AND NATURE PRESERVES Parks serve a variety of purposes. They can teach us about our past and provide sanctuaries where nature is allowed to grow and develop in its own way. They are havens not only for wild plants and animals but also for the human spirit.   Park Problems Today many parks have become islands of nature surrounded and threatened by destructive land uses and burgeoning human populations that crowd park boundaries. Some parks have become so crowded by visitors.

Parks and Preserves

Parks and Preserves The idea of providing natural space for recreation, and to preserve natural environments, has really developed in the past 50 years (fig. 6.18). While the first parks were intended mainly for the recreation of growing urban populations, parks have taken on many additional purposes. Today we see our national parks as playgrounds for rest and recreation, as havens for wildlife, as places to experiment with ecological management, and as opportunities to restore ecosystems. Not all preserves are preserved: Even parks and preserves designated with a high level of protection aren’t always safe from exploitation or changes in political priorities. Serious problems threaten natural resources and environmental quality in many countries. In Greece, the Pindus National Park is threatened by plans to build a hydroelectric dam in the center of the park. Furthermore, excessive stock grazing and forestry exploitation in the peripheral zone are causing erosion and loss of wildlife habitat.

Visitors demand services such as golf courses, laundries, grocery stores, and other facilities which affect the natural beauty. Air pollution has become a serious threat to parks as well. The optimum size for nature preserves depends on the terrain and the values they are intended to protect, but in general, the larger the reserve, the more species it can protect. Establishing corridors to link separate areas can be a good way to increase effective space and to allow migration from one area to another. Economic development and nature protection can go hand in hand.

Park Problems Development pressures at boundaries Overcrowding and visitor demands for facilities Pollution, noise, and environmental degradation due to motorized vehicles Mining and oil interests

WORLD PARKS AND PRESERVES Global parks and preserves face innumerable challenges, but the statistics have been improving in recent years. There are several reasons for a global increase in protected areas. International nongovernmental organizations have developed a range of tactics including debt-for-nature swaps to establish preserves. Consumer pressure has forced logging and mining companies to collaborate in preserving forests. Governments are increasingly interested in slowing resource depletion and in gaining status by protecting lands.

To satisfy the conflicting needs and desires of humans and nature, we may need a spectrum of preserves with decreasing levels of interference and management, including: Recreation areas, designed primarily for human entertainment, aesthetics, and enjoyment. Historic areas, intended to preserve a landscape as we imagine it looked in a previous time. Conservation reserves, set aside to maintain essential ecological functions, preserve biodiversity, or protect a particular species or group of organisms. Pristine research areas, to serve a baseline of undisturbed nature. Inviolable (no violations) preserves, for sensitive species and from which all human entrance is strictly prohibited.

Marine ecosystems need greater protection

Marine Reserves Ocean fish stocks become increasingly depleted globally. Research has shown that “no-take” refuges not only protect the species living within them but also serves as nurseries for nearby areas. Coral reefs are among the most threatened marine ecosystems in the world. Remote sensing surveys show that worldwide living coral covers only about 285,000 km 2 (110,000 mi 2 ), or an area about the size of Nevada. This is less than half of previous estimates, and 90 percent of all reefs face threats from rising sea temperatures, destructive fishing methods, coral mining, sediment runoff, and other human disturbance.

Conservation and economic development can work together Ecotourism is tourism that is ecologically and socially sustainable. It can be more beneficial in many places over the long term than extractive industries, such as logging and mining.

Should preserves be large or small? One of the reasons large preserves are considered better than small preserves is that they have more core habitat, areas deep in the interior of a habitat area, and that core habitat has better conditions for specialized species than do edges. Edge effects is a term generally used to describe habitat edges: for example, a forest edge is usually more open, bright, and windy than a forest interior, and temperatures and humidity are more varied. For a grassland, on the other hand, edges may be wooded, with more shade, and perhaps more predators, than in the core of the grassland area. As human disturbance fragments an ecosystem, habitat is broken into increasingly isolated islands, with less core and more edge. Small, isolated fragments of habitat often support fewer species, especially fewer rare species, than do extensive, uninterrupted ecosystems. The size and isolation of a wildlife preserve, then, may be critical to the survival of rare species.

Landscape Ecology A science that examines the relationship between spatial patterns and ecological processes

Size and Design of Nature Preserves: The exact design and the size of preserves is always a subject of debate. In particular, the question comes up: is it better to have several small reserves that are closer to places where people might champion the cause for that preserve, or is it better to have a single large preserve? A key concept that comes into play here is that of edge effect, or the boundary between different habitats. Scientists have learned that creating preserves with too much edge effect can have negative impacts on biodiversity.

The concept of corridors is also important when designing preserves. Corridors are areas that wildlife need to migrate. Corridors sometimes can connect several small reserves. Spreading reserves out over a larger area by creating several small reserves can reduce the potential for the reserve to be eliminated by a natural catastrophe such as a hurricane or flooding. On the other hand, having a larger single reserve reduces the impact of edge effects and could potentially maintain corridors for animals to migrate through.

Practice Quiz 1. What do we mean by closed-canopy forest and old-growth forest? 2. What land use is responsible for most forest losses in Africa? In Latin America? In Asia? (fig. 6.7). 3. What is a debt-for-nature swap? 4. Why is fire suppression a controversial strategy? Why are forest thinning and salvage logging controversial? 5. What portion of the United States’ public rangelands are in poor or very poor condition due to overgrazing? Why do some groups say grazing fees amount to a “hidden subsidy”?

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Practice Quiz continued… 6. What is rotational grazing, and how does it mimic natural processes? 7. How do the size and design of nature preserves influence their effectiveness? What do landscape ecologists mean by interior habitat and edge effects? 8. What percentage of the earth’s land area has some sort of protected status? How has the amount of protected areas changed globally (fig. 6.18)? 9. What is ecotourism, and why is it important? 10. What is a biosphere reserve, and how does it differ from a wilderness area or wildlife preserve?