1 / 17

Chapter 55

Chapter 55. Conservation Biology & Restoration Ecology. Human Activities threaten Earth’s Biodiversity. Approximately 50% of land surface on earth has been altered by humans The same holds true with freshwater.

miyo
Download Presentation

Chapter 55

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 55 Conservation Biology & Restoration Ecology

  2. Human Activities threaten Earth’s Biodiversity • Approximately 50% of land surface on earth has been altered by humans • The same holds true with freshwater. • It is estimated that the rate of extinction of species is greater than any time on earth. • While extinctions do naturally occur, it is the current rate of extinctions which cause scientists to become alarmed.

  3. Restoration ecology applies ecological principles • An effort to return degraded ecosystems to conditions similar as possible to their natural state • Throughout the biosphere, human activities are altering ecosystem processes on which we and other species depend • We are dependent on other organisms, the environment; the biosphere!!

  4. The Three Levels of Biodiversity • Biodiversity has three main components • Genetic diversity • Species diversity • Ecosystem diversity

  5. Genetic Diversity • Genetic diversity comprises • The genetic variation within a population • The genetic variation between populations

  6. Species Diversity • Is the variety of species in an ecosystem or throughout the biosphere • Greater species diversity = a healthier ecosystem • An endangered species is one that is in danger of becoming extinct throughout its range • Threatened species are those considered likely to become endangered in the future

  7. Conservation biologists are concerned about species loss Threatened with extinction Extinction status • 12% of known species of birds • 24% of mammals • 200 plant species in U.S. have become extinct since records have been kept • 20% of known freshwater fishes are now extinct or threatened • 32% all known amphibian species are either extinct or endangered • If current rates of extinction hold true, >1/2 plant & animal species will be gone by end of this century!

  8. Ecosystem diversity • Identifies the variety of ecosystems in the biosphere • Is being affected by human activity • >50% wetlands in U.S. have been drained and converted into other ecosystems • About 90% of native riparian communities in CA, AZ and NM have been destroyed by overgrazing, flood control, water diversion and invasive plants

  9. Benefits of Species & Genetic Diversity • Humans feel a sense of connection to nature & other forms of life (Biophilia) • We benefit from biotechnology such as pharmaceuticals generated from plants • (Bioprosepecting) where corporations are currently trying out new ways to use genes to develop new medicines, foods, petroleum substitutes…

  10. Ecosystem Services • Entire ecosystems also benefit humans. Ecosystems: • Purify our air & water • Reduce severity of droughts and floods • Generate & preserve fertile soils • Detoxifies & Decomposes waste • Pollinates crops, Disperses Seeds • Controls pests that threaten our crops • Moderates weather extremes

  11. 4 major threats to Biodiversity • Habitat destruction • Introduced species • Overexploitation • Disruption of “interaction networks”

  12. Habitat Destruction • Is the single greatest threat to biodiversity • Includes habitat fragmentation

  13. Introduced Species • Are those that humans move from native locations to new geographic regions • Usually disrupt their adopted community • ex. Zebra mussels

  14. Overexploitation • Harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound • Ex. Fishing industry/North Atlantic Bluefin Tuna now less than 20% of its population in 1980 • Elehants, whales and rhinos are vulnerable due to low repro. rates

  15. Population conservation • Focuses on: • Population size, genetic variability & critical habitat • May lead to The Extinction Vortex, where small populations lose genetic variability due to inbreeding. • This may lead to extinction as the population loses its ability to reproduce successfully • Not all populations are affected this way…depends on the species.

  16. Minimum Viable Population Size (MVP) • The minimum population size at which a species is able to sustain its numbers & survive • Effective Population Size is an estimate of MVP • Population viability analysis (PVA) • Predicts a population’s chances for survival over a particular time.

More Related