Transcript Slide 1
Ecosystem Conservation Human Impact versus Needs Patterns of Resource Use Public and Private Lands The Human Impact • Increased population growth: – Increasing our biotic potential. – Decreased our environmental resistance. • Contributions to ecosystem degradation: – Introduce species – Eliminate natural predators – Alter abiotic factors – Reduce biodiversity – Misunderstand the role of fire • Have we exceeded our carrying capacity? Implications For Humans • We need to protect and manage the natural environment to maintain the goods and services vital to human economy and survival. • Establishing a balance between our own species and the rest of the biosphere should be a practical goal for all of us, if not also a moral goal. • Adaptive Ecosystem Management: an approach that accepts uncertainty of our knowledge base and flexible to change as new information is gathered; the goal is to balance our exploitation with an ecosystem’s capacity to renew goods and services. Ecosystem Goods (Resources): Which are renewable which are finite? 33 trillion dollars worth globally (1977)! Ecosystem Services: (also see Table 3-3) 1)Modification of the climate Water absorbs energy during evaporation and releases energy when is condenses, thus atmosphere moves heat in water around the globe; ocean currents also transport heat globally. 2) Maintenance of the hydrological cycle Precipitation absorbed and slowly released; flood prevention. 3) Erosion control & soil formation Plants and detritus intercept the force of rain and the greater surface area absorbs more water; plants, animals and microbes are involved in creating soils. 4) Maintenance of O- and N-Cycles Photosynthesis release oxygen; Nitrogen-fixation maintains soil and aquatic habitat fertility. 5) Waste and toxic chemical treatment Water dissolves most everything and dilutes to levels that microbes can degrade organic toxins. Microbes transform inorganic toxins. 6) Pest Management Ecosystems have natural predators and diseases for organisms we call pests. When predators are maintained, ecosystems control pests. 7) Carbon storage; maintain the C-Cycle The ocean, forests and their soils contain huge stores of carbon relative to the atmosphere. Maintaining ecosystem health may buffer (counteract) fossil fuel inputs. e.g. Wetlands • Service valued at $100,000 per acre per year. • Water purification and fish propagation • Many lose very few gain. Conservation versus Preservation: • Manage or regulate use so not to exceed the capacity to renew a species or service. • Ensure continuity regardless of human utility. • Both may involve a “no use” strategy. Patterns of Human Use: • Consumptive Use • Productive Use • Maximum Sustainable Yield (MSY) • Tragedy of the Commons Maximum Sustainable Yield The highest rate of use that will be balanced by recruitment. Given uncertainties, what is the precautionary approach to setting total allowable catch limits? Tragedy of the Commons • Common = everyone has access of use. • Begins with unregulated access to a resource owned by no one. Examples? – Pastureland – Oyster beds – Offshore fisheries • Harvest based on largest amount over the shortest period of time. • No thought given to sustainable harvests. • Usually ends with no resource for anyone. Preventing a Tragedy of the Commons • Private ownership • Regulated access – – – – Protection for sustained benefits Fairness in access rights Mutual consent of the regulated Works best when under local control Restoration Ecology • Repair damaged ecosystems to return it to normal function and restore the native flora and fauna. • Difficulties arise when: – Lack of knowledge on prior condition – Severely disturbed or lost soils – Accumulations of pollutants – Dominance of exotic (introduced) species Publicly Owned Lands (40%) in the U.S. Wilderness Act of 1964 • Provides for permanent protection of undeveloped and unexploited areas so that natural ecological processes can operate freely; greatest protection level. • 5% of land area in U.S. is “wilderness”. • The goal is preservation not conservation. • No permanent structures or motor vehicles. • No increase in over 30 years. Parks and Refuges • National Parks (U.S. National Park Service) • National Wildlife Refuge (U.S. Fish and Wildlife Service) • Protect areas of great scenic or unique ecological significance. • Protect important wildlife species. • Provide public access Yellowstone Ecosystems • Parks boundaries don’t represent the entirety of an ecosystem. • Partnering of local stakeholders to connect patches of habitat of the original “complete” ecosystem. • National Forest Service lands and private land trusts are both involved. Protected by the Greater Yellowstone Coalition National Forests • Only 5% of the original U.S. Forests are left • Most U.S. Forests are second growth • U.S. National Forest Service manages 7% of the land area in the U.S. and that managed by Bureau of Land Management is 11% (most not forested). Private Land Trusts • Non-profit Organizations • Protect natural areas from development by: – Receive land as a gift. – Accept easements – Private land purchases. • Examples: – Land Trust Alliance – Nature Conservancy – Trustees of Reservations in Massachusetts (1891)