Presentation on theme: "By: Brooke Sergas and Madi Ennenga. Humans have depleted and degraded some of the earth’s biodiversity and these threats are expected to increase. According."— Presentation transcript:
By: Brooke Sergas and Madi Ennenga
Humans have depleted and degraded some of the earth’s biodiversity and these threats are expected to increase. According to a 2002 study on the impact of the human ecological footprint on the earth’s land, we have distributed to some extent at least half and probably 83% of the earth’s land surface. Most of this is the result of filling in wetlands and converting grasslands and forests to crop fields and urban areas. Human activities such as agriculture, industry, economic production and consumption, and recreation cause degradation and destruction of natural ecosystems, changes in number and distribution of species, pollution, and alteration of natural chemical cycles and energy flows.
Forests provide a number of ecological and economic services and researchers have attempted to estimate their total monetary value. Forests provide economic services such as fuelwood, lumber, pulp to make paper, mining, livestock grazing, recreation, and jobs. In order to be sustained, the U.S. needs to support energy flow and chemical cycling, work to reduce soil erosion, absorb and release water, purify water and air, influence local and regional climate, store atmospheric carbon, and provide numerous wildlife habitats.
Large areas of ecologically and economically important tropical forests are being cleared and degraded at a fast rate. Tropical forests cover about 6% of the earth’s land area. Climatic and biological data suggest that mature tropical forests once covered at least twice as much area as they do today. Studies indicate that at least half of the world’s species of terrestrial plants and animals live in tropical rain forests. Each time a tract of tropical rain forest is cleared, several species may be lost forever. We can prevent deforestation of tropical forests by protecting the most diverse endangered areas, educating settlers about sustainable agriculture and forestry, adding subsidies that encourage unsustainable forest use, protecting forests with debt-for-nature swaps and conservation easements, certifying sustainably grown timber, and reducing illegal cutting.
Almost half of the world’s livestock graze on natural grasslands and managed grasslands. Grasslands provide important services such as soil formation, erosion control, nutrient cycling, storage of atmospheric carbon, gene pools for crossbreeding gain crops, and maintaining biodiversity. We can sustain rangeland productivity by controlling the number and distribution of livestock and by restoring degraded livestock. A widely used method for sustaining grasslands is rotational grazing in which cattle are confined by portable fencing one area for a short time and then moved to a new location.
Countries have established more than 1,100 national parks, but most are threatened by human activities. Local people invade most parks in search of wood, cropland, game animals, and other natural products for their daily survival. Most national parks are also too small to sustain many large-animal species and many parks suffer from nonnative species. In order to manage parks, we should integrate plans for managing parks and nearby federal lands, add new parkland near threatened parks, buy private land inside parks, locate visitor parking outside parks and use shuttle buses for entering and touring heavily used parks, increase funds for park maintenance and repairs, survey wildlife in parks, limit the number of visitors to crowded parks areas, raise entry fees for visitors to use funds for park management and maintenance, and encourage volunteers to give visitor lectures and tours.
Ecologists call for protecting more land to help sustain biodiversity, but powerful economic and political interests oppose doing this. The best way to protect biodiversity is to create a world-wide network of protected areas. Conservation biologists call for full protection of at least 20% of the earth’s land area in a global system of biodiversity reserves that includes multiple examples of all the earth’s biomes. We can establish and connect nature reserves in a large eco-region.
Wilderness is land legally set aside in a large enough area to prevent or minimize harm from human activities. Wild places are areas where people can experience the beauty of nature and observe natural biological diversity. They can also enhance the mental and physical health of visitors by allowing them to get away from noise, stress, development, and large numbers of people. To most biologists, the most important reasons for protecting wilderness and other areas from exploitation and degradation are to preserve their biodiversity as a vital part of the earth’s natural capital and to protect them as centers for evolution in response to mostly unpredictable changes in environmental conditions.
Almost every natural place on earth has been affected or degraded to some degree by human activities. Ecological restoration is the process of repairing damage caused by humans to the biodiversity and dynamics of natural ecosystems. Ecologists agree that preventing ecosystem damage in the first place is cheaper and more effective than any form of ecological restoration. Scientists say that restoration should not be used as an excuse for environmental destruction. We have been able to protect or preserve 5% of the earth’s land from the effects of human activities. Ecological restoration is badly needed for many of the world’s ecosystems that we have already damaged.
In order to sustain earth’s terrestrial biodiversity, we need to take immediate action to preserve the world’s biological hot spots, keep intact the world’s remaining old-growth forests and cease all logging of such forests, and complete mapping of the world’s terrestrial and aquatic biodiversity so we know what we can make conservation efforts more precise and cost-effective. We can determine the world’s marine hot spots and assign them the same priority for immediate action as for those lands, concentrate on protecting and restoring world’s water systems, make conservation profitable, and initiate ecological restoration projects worldwide.
Old Growth Forests- an uncut or regenerated forest that has not been seriously distributed by human activities or natural disasters for at least several hundred years. Second Growth Forest- a stand of trees resulting from secondary ecological succession. Develop after trees in an area have been removed by human activities. Rangelands- unfenced grasslands in temperate and tropical climates that supply forage or vegetation for grazing and browsing animals. Pastures- managed grasslands or enclosed meadows usually planted with domesticated forage. - Overgrazing: occurs when too many animals graze for too long and exceed carrying capacity of the grassland area. - Undergrazing: absence of grazing for long periods can reduce the net primary productivity (npp) of grasslands vegetation and grass cover.
Selective cutting- intermediate-aged or mature trees in an uneven-aged forest are cut singly or in small groups. - Creaming: selective cutting in which all or most of the largest trees are removed; leads to environmental degradation. Tree Plantation or Tree Farm- a managed tract with uniformly aged trees of one or two genetically uniform species that are harvested by clear cutting as soon as they become commercially valuable. Buffer Zone Concept- protecting an inner core of a reserve by establishing two buffer zones in which people can extract resources in ways that are sustainable and do not harm the inner core. Instrumental Value- value of an organism, species, ecosystem, or the earth’s biodiversity based on its usefulness to humans. Intrinsic Value- value of an organism, species, ecosystems, or the earth’s biodiversity based on existence, regardless of whether it has any usefulness to human. Healthy Forest Restoration Act- timber companies are allowed to cut down economically valuable medium sized and large trees in 71% of the total area of national forests in return for clearing away smaller more fire prone trees and underbrush.