CES210 Chapter 11
CES210 Chapter 11 CES 210
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This 4 page Class Notes was uploaded by Emma Eiden on Tuesday October 11, 2016. The Class Notes belongs to CES 210 at University of Wisconsin - Milwaukee taught by Mai Phillips in Fall 2016. Since its upload, it has received 185 views. For similar materials see Introduction to Conservation and Environmental Science in GN Natural Science at University of Wisconsin - Milwaukee.
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Date Created: 10/11/16
CES210: Conservation and Environmental Science Chapter Eleven: Biodiversity: Preserving Species BIODIVERSITY AND THE SPECIES CONCEPT What is biodiversity? - Three kinds of biodiversity are essential to preserve ecological systems: 1. Genetic diversity is a measure of the variety of different versions of the same genes within individual species 2. Species diversity describes the number of different kinds of organisms within individual communities or ecosystems 3. Ecological diversity assess the richness and complexity of a biological community, including the number of niches, trophic levels, and ecological processes that capture energy, sustain food webs, and recycle materials within this system - Within species diversity, we can distinguish between species richness (the total number of species in a community) and species evenness (the relative abundance of individuals within each species) Species are defined in different ways - A general term for this is reproductive isolation – that is, organisms may be unable to breed because of physical characteristics, location, habitat, or even differing courtship behaviors - Another definition favored by many evolutionary biologists is the phylogenetic species concept (PSC), which emphasizes the branching (or cladistic) relationships among species or higher taxa, regardless of whether organisms can breed successfully - A third definition, favored by some conservation biologists, is the evolutionary species concept (ESC), which defines species in evolutionary and historic terms rather than by reproductive potential Molecular techniques are rewriting taxonomy - Increasingly DNA sequencing and other molecular techniques are giving us insights into taxonomic and evolutionary relationships - The new technology can help resolve taxonomic uncertainties in conservation How many species are there? - The 1.7 million species presently known probably represent only a small fraction of the number that exist - About 65% of all known species are invertebrates (animals, without backbones, such as insects, sponges, clams, and worms) - The numbers of endangered species are those officially list by the International Union of Conservation of Nature and Natural Resources (IUCN). This represents only a small fraction of those actually at ricks. It’s estimated that 1/3 of all amphibians, for example, are declining and threaten with extinction Hot spots have exceptionally high biodiversity - The greatest concentration of different organisms tends to be in the tropics, especially in tropical rainforests and coral reefs. Norman Myers, Russell Mittermeier, and other have identified biodiversity hot spots that contains at least 1,500 endemics (species that occurs nowhere else) and have lost at least 70% of their habitat owing to, for example, deforestation or invasive species - Wetlands, for instance, may contain just a few, common plant species, but they perform valuable ecological services, such as filtered water, regulating floods, and serving as nurseries for fish - Anthropologists point out that many of the regions with high biodiversity are also home to high cultural diversity as well We benefit from biodiversity in many ways - We benefit from other organisms in many ways, some of which we don’t appreciate until a particular species or community disappears - Many wild plant species could make important contributions to human food supplies, either as new crops or as a source of genetic material to provide diseases resistance or other desirable traits to current domestic crops. - Norman Myers estimates that as many as 80,000 edible wild plant species could be utilized by humans - More than half of all modern medicines are either derived from or modeled on natural compounds from wild species - Many consider this expropriation “biopiracy” and call for royalties to be paid for folk knowledge and natural assets Biodiversity provides ecological services and brings us many aesthetic and cultural benefits - Human life is inextricably linked to ecological services provided by other organisms. Soil formation, waste disposal, air and water purification, nutrient cycling, solar energy absorption, and management of biogeochemical and hydrological cycles all depend on the diversity of life. Total value of these ecological services is at least $33 trillion per year, or about half the world GNP - It is estimated that 95% of the potential pests and disease-carrying organisms in the world are controlled by other species that prey upon them or compete with them in some way - Nature appreciation is economically important - Ecotourism can be a good form of sustainable economic development, although we have to be careful that we don’t abuse the places and cultures we visit - They argue that existence value, based on simply knowing that a species exists, is reason enough to protect and preserve it WHAT THREATENS BIODIVERSITY? - Extinction- the elimination of a species is a normal process of the natural world. Species die out and are replaced by others, often their own descendants, as part of evolutionary change Extinction is a natural process - Studies of the fossil record suggest that more than 99% of all species that ever existed are now extinct We are accelerating extinction rates - The rate at which species are disappearing appears to have increased dramatically over the last 150 years. It appears that between 1600 and 1850 C.E. human activities were responsible for the extermination of two or three species per decade. By some estimates, we are now losing species at hundreds or even thousands of times natural rates - Most predications of anthropogenic mass extinction are based on an assumption that habitat area and species abundance are tightly correlated - E.O. Wilson summarizes human threats to biodiversity with the acronym HIPPO, which stands for Habitat destruction, Invasive species, Pollution, Population (of humans), and Overharvesting. Habitat destruction is the principal HIPPO factor - Of the five HIPPO factors, habitat loss is often the most important extinction threat - Climate change caused by our releases of greenhouse gasses is one of the most important examples of human-caused habitat loss. Biologists have observed dozens of species whose territories migration patterns, or behaviors have been altered by climate change Invasive species displace resident species - Those that do thrive crowd out native species, alter habitats, and may undermine ecosystem function. We call organisms that readily invade new territory invasive species. Non-native invasive often are especially successful because they are free of the predators, diseases, or resource limitations that controlled their populations in their native habitat - Sometimes native species can suddenly become invasive when environmental condition change. The crown-of-thorns starfish, for example, is widely distributed in tropical oceans Pollution and population are direct human impacts - Lead and mercury poisoning are another major cause of mortality for many species of wildlife - Human population growth is a threat to biodiversity because everyone has some consumption needs – although some people consume more than others Overharvesting results when where is a market for wild species - Overharvesting, the last of the HIPPO factors, is responsible for depletion or extinction of many species Overharvesting is often illegal and involves endangered species - Tiger or leopard fur coats can bring $100,000 in Japan or Europe. The population of African black rhinos dropped from about 100,000 in the 1960s to about 3,000 in the 1980s because of a demand for their horns. In Asia, where it is prized for its supposed medicinal properties, powdered rhino horn fetches $28,000 per kilogram. Similarly, elephants are being slaughtered by the thousands every year for the illicit ivory trade Island ecosystems are especially vulnerable to invasive species - New Zealand is a prime example of the damage that can be done by invasive species is island ecosystems. New Zealand’s flora and fauna are particularly susceptible to the introduction of alien organisms ENDANGERED SPECIES MANAGEMENT Hunting and fishing laws have been effective - By the 1890s most states had enacted some hunting and fishing restrictions. The general idea behind these laws was to conserve the resource for future human use rather than to preserve wildlife for its own sake. The wildlife regulations and refuges established since that time have been remarkably successful for many species The Endangered Species Act is a powerful tool for biodiversity protection - As defined by the ESA, endangered species are those considered to be in imminent danger of extinction, whereas threatened species are those that are likely to become endangered – at least locally – in the foreseeable future - Vulnerable species are naturally rare or have been locally depleted by human activities to a level that puts them at risk - The ESA regulates a wide range of activities involving endangered species, including “taking” (harassing, harming, pursuing, accidentally or on purpose; importing into or exporting out of the United States; possessing, selling, transporting, or shipping; and selling or offering for sale any endangered species. Prohibitions apply to live organisms, body parts, and products made from endangered species Recovery plans rebuild population of endangered species - Among the difficulties are costs, politics, interferences by local economic interests, and the fact that once a species is endangered, much of its habitat and its ability to survive are likely already compromised - Some recovery plans have been remarkably successful Private land is vital for species protection - 80% of the habitat for more than half of all listed species the United States is on private land. The Supreme Court has ruled that destroying habitat is as harmful to endangered species as directly taking (killing) them. Many landowners, however, resist restrictions on how they use their own property to protect what they perceive as insignificant or worthless organisms - To reduce these tensions, the Fish and Wildlife Service negotiates agreements called habitat conservation plans (HCPs) with private landowners. Under these plans, landowners are allowed to harvest resources or build on part of their land as long as the species benefits overall Endangered species protection is controversial - In the western United States, where traditions of individual liberty and freedom are strong and the federal government is viewed with considerable suspicion and hostility, the ESA seems to many to be a diabolical plot to take away private property and trample of individual rights Gap analysis promotes regional planning - Over the past decade, growing numbers of scientists, land managers, policymakers, and developers have been making the case that it is time to focus on a rational, continent-wide preservation of ecosystems that support maximum biological diversity rather than a species-by- species battle for the rarest or most popular organisms - The gaps between protected areas may contain more endangered species than are preserved within them. This observation has led to an approach called gap analysis in which conservationists and wildlife managers look for unprotected landscapes that are rich in species International treaties improve protection - The 1975 Convention on International Trade in Endangered Species (CITES) was a significant step toward worldwide protection of endangered flora and fauna CAPTIVE BREEDING AND SPECIES SURVIVAL PLANS - Breeding programs in zoos and botanical gardens are one way to attempt to save severely threatened species Zoos can help preserve wildlife - Some zoos now participate in programs that reintroduce endangered species to the wild - Hawaii’s endemic nene also have been successfully bred in captivity and reintroduced into the wild - Today there are an estimated 17,480 southern white rhinos, mainly in national parks and private game ranches - Moreover, bats, whales, and many reptiles rarely reproduce in captivity and still come mainly from the wild We need to save rare species in the wild - “Zoos need to get out of their own walls and put more effort into saving the animals in the wild.” An interesting application of this principle is a partnership between the Minnesota Zoo and the Ujund Kulon National Park in Indonesia, home to the world’s few remaining Javanese rhinos
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