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Transcript
Ch. 18 Part 4 Importance of Biodiversity Threats to Biodiversity 1. Habitat loss and degradation of environment 2. Climate change 3. Excessive use of fertilizers and industrial/domestic forms of pollution 4. Overexploitation and unsustainable use of resources 5. Effects of Invasive species/Alien Species on native species – endemics Habitat Loss • Destruction of the natural environment – Deforestation large impact on biodiversity • Slash and burn • Decrease biodiversity for crops and ranching (low biodiversity) – Monocultures • Leads to severe land degradation as a result of SOIL EROSION once plants are removed – – – – – – Removal of vegetation for: Agriculture Housing Transport Leisure activities Industrial – Habitat Fragmentation habitats of plants and animals divided into smaller areas • Fishing Overexploitation – Difficult to know if fish stocks are sustainable – Overfishing extinction – Fisheries with declining/collapsing populations of fish • Grand Banks, North Atlantic cod • North Sea herring • East China sea Variety of Species – Steep decrease in predatory fish increasing fishing of smaller fish/lower on food chain • Affects marine mammal populations that depend on smaller fish for food • Logging – Removing trees faster than they can be regenerated – Teak & Mahogany Loss of Single Species affecting Community • Sea otters, kelp, and sea urchins Loss of Sea Otter (Enhydra lutris) • Catastrophic loss of many other species (sea kelp) • Sea otter central role in maintaining ecosystem (keystone species) • Placed on endangered species list numbers increased • Currently hunted by killer whale – Killer whales food supply is down because of overfishing Examples of Keystone Species • Euhydra lutris (sea otter) • Loxodonta Africana (bush elephant) Pollution • Industrial and domestic waste – Attempts to reduce impact on environment • Sewage treated before it reaches aquatic ecosystems – Not prevalent around the world • Pollution consists of chemicals that animals bodies cannot metabolize or excrete – Polychlorinated Biphenyls (PCBs) » Waste from manufacturing processes » Not treated before released into environment » Enters food chains biological magnification » Weakens immune systems & fertility in organisms – Plastics in Oceans » Non-biodegradable » Bags, nets Fertilizers • Areas affected farmlands (low-lying land near coast) • Unabsorbed fertilizer (not taken in by crops) become runoff into lakes, rivers, and streams ocean • Extra nutrients excessive growth of producers (algae) EUTROPHICATION – Occurs faster than feeding rate of herbivores that consume them – Algae produces toxic substances that affect other organisms in ecosystem – Unbalanced food web – Excessive algae growth DECREASES biodiversity • Affects terrestrial and aquatic ecosystems • Sulfur Dioxide in atmosphere bad – Formed by combustion of fuel with high sulfur content (coal) – Sulfur Dioxide + water vapor in atmosphere = acid rain • Destroys vegetation • Acidification of aquatic ecosystems downwind of industrial area • Few animals can survive/bred in low pH water • Biodiversity decreased Air Pollution Climate Change • Caused by build up of green house gasses in atmosphere • Increase in carbon dioxide and methane (green house gases)in atmosphere due to: • Industrialization • Extraction and combustion of fossil fuels • Excess methane – Cattle ranching – Rice farming – Anaerobic breakdown of waste at land fills • Global warming produces changes in distribution of terrestrial ecosystems – – – – – Migration patterns Acidification of oceans Temperature changes in oceans Sea levels rising Frequency of natural catastrophes Climate Change • Migration patterns – North/south to cooler climates – Excess competition with decreasing # of cooler areas • Acidification of oceans – Affects organisms that rely on calcium carbonate for shells and skeletons • Temperature changes in oceans – Symbiotic relationship disrupted f temp remains to high – Organisms leave coral coral bleaching occurs death of coral decrease biodiversity less protection for coastline ecosystems • Sea levels rising – Affect productive coastal ecosystems – Range of ecosystems restricted – Fragmentation occurs • Frequency of natural catastrophes – Natural disasters increase – Example: – Following natural disasters (typhoons and hurricanes) is flooding of coastal ecosystems • • • • • • Excess nutrients in coastal waters Increase phytoplankton growth Excess food for larvae of star fish Adult starfish eat coral Normally coral runs our and starfish population deceases and coral regrows every ten years More frequent disasters coral unable to catch up biodiversity reduced -> ecosystem destroyed Importance of Biodiversity 1. Moral & Ethical Reasons – Humans have responsibility 2. Ecological Reasons – Higher diversity = less chances of being disputed by changes in environmental conditions (natural or man made) – Ecosystems high value to humans – Drugs (antibiotics) – Example: Madagascan periwinkle & Pacific Yew Tree drug paclitaxel Taxol – Plants provide high value to humans 3. Aesthetic Reasons – Ecotourism important to economies – Sense of pleasure Importance of Biodiversity 4. Social & Commercial Reasons – Crop plants low genetic diversity – Wild plants/variants source of genetic variation and diversity – Provide important alleles that can be introduced by interbreeding with crop plants & gene technology – Microorganisms as a producer of enzymes important in medicine • Some of these only exist in certain ecosystems 5. Other services – Absorption of carbon dioxide (forests and bogs) – Break down of organic waster in water (by microorganisms) – Transpiration of water by plants fresh water for humans – Recycling of matter (termites, ants, fungi, bacteria) • Supply nitrates, phosphates, and sulfates to soil for plant growth (effects entire food chain, all trophic levels) Protecting Endangered Species • Endangered species species that is threatened with extinction • Variety of protection methods – Best: keep species in natural habitat • All life support systems provided • High profile conservation programs – Focus on large mammals • Protection of entire ecosystems important – Tropical rainforest – Karst limestone National Parks • Areas of land controlled by government of a country and protected by legislation • Government sets aside areas of land where wildlife and environment are protected • Human activities limited – – – – – – Limits on building Grazing of animals Hunting Agriculture Mining Industrial activities • Act as conservation areas of wild life Yellowstone National Park • 1st national Park, USA, 1872 – Last remaining, intact ecosystem of the northern climatic zone – Conservation & recreational area – Home to threatened and endangered animals Galapagos Islands • • • • • • • • • Ecuador Est. 50years ago Conservation park Restricted access to uninhabited islands Limited access to areas sensitive to human interference Marine reserve of 133 000 km2 set up to protect environment from fishing Alien Animal species removed Invasive plants removed Captive breeding and reintroduction programs coordinated by the Charles Darwin Research Station National Parks and Awareness • Restrictions on human activities • Tourism important – Money finds maintenance of parks & education about conservation – Increases awareness of important issues – Public can help – Involvement of local people important • Allowing them to use certain areas of the park • Employing locals • Use money from parks to improve healthcare facilities and educational facilities Marine Parks • Set up to conserve fragile ecosystems at risk of: – Overfishing – Dredging – Pollution • Improving biodiversity can improve fish catching as well • Marine reserve off coast of Little Cayman – Protects spawning ground of endangered fish, Epinephelus striatus (Nassau grouper) International Conservation Areas • Ramsar sites – Wetlands considered to be important in conservation of wildlife • Estuaries, salt marshes, blanket bogs, ponds, mangroves • High biodiversity – Designated under treaty signed by Ramsar in Iran in 1971 • States that designated areas must be used wisely • Gives protection against building development and extraction of minerals Management of Parks and Reserves • Vary from area to area – Some countries have resources while others do not • Government support • Money • Threats remain great – Some species removed from natural areas and placed somewhere safer Zoos • Protection for endangered and vulnerable species • Successful captive breeding programmes – Goal is reintroduction to native habitat • Important role in research 1. Gaining better understanding of breeding habitats 2. Habitat requirements 3. Increasing genetic diversity Captive Breeding Programmes • Goal: Reintroduce animals to natural habitat – Difficult • Many factors affect success • Successful breeding programs: – Blue-and –Gold Macaw Ara ararauna – Scimitar-horned oryx Oryx dammah Problems with Captive Breeding Programmes • Inbreeding • Low genetic diversity • Aim of captive breeding programmes is to maintain genetic diversity – Females mate with different males – Example: Cheetah • Refusal of animals to breed in captivity • Difficulty of returning to wild and surviving after being cared for – Do not acquire natural skills in captivity – Example: pandas and golden lion tamarins Assisted Reproduction • Solution to problem of inbreeding – Transport of large animals between zoos (captive breeding programs) • Difficult • Expensive • Breeding not guaranteed • Problem males and females do not show courtship behavior • Alternate Option Sperm Banks • Less expensive • Sperm samples from males collected, checked for activity, diluted with medium and albumen; stored in thin tubes called straws and kept in liquid nitrogen Methods of Assisted Reproduction • Artificial Insemination (AI) – Straw placed in warm water to activate sperm – Straw placed into catheter that has been placed into female reproductive organs (to reach uterus) when female is in “heat” (ovulating) • Hormone treatment needed sometimes superovulation = large # of follicles • Embryo transfer occurs (following AI) – embryos removed (flushed out) of uterus & transferred to female who has had pregnancy hormone treatment (surrogate mother) • Same species not required – Reason: protects endangered animal from risks of pregnancy used for more offspring Methods of Assisted Reproduction • In vitro Fertilization (IVF) – Oocytes collected • Needle is inserted into ovaries • Mature follicles extracted • Oocytes kept in culture medium for short time • Oocytes mixed with semen • Zygotes form – Divide into embryos • Embryos cultured for several days • Embryos placed back into mother OR several females of different species – Ooocyte & Embryo storage • Similar to sperm • More difficult – Damage likely with freezing/thawing process » Eggs are large cells with large water component » Water inside egg forms ice crystals damage internal membranes of cell – Eggs fertilized in vitro THEN frozen until surrogate mother is available Frozen Zoos • Holds genetic resources in form of: – Sperm – Eggs – Embryos • Genetic info is from endangered and vulnerable species • Can hold more genetic diversity than a normal zoo • Material can be kept for long periods of time • Example: – San Diego Zoo Problems of Successful Conservation • Organism saved from extinction BUT numbers are TOO HIGH beyond carrying capacity that ecosystem can support • Culling – Practice of taking something out of the breeding population • Birth control – neutering/spaying » Vasectomy (cutting of sperm duct) – Female chemical contraceptives (non-steroid hormones) » Vaccines targets ZONA PELLUCIDA (region surrounding layer of glycoproteins around the egg) • Stimulate immune response to make antibodies AGAINST the glycoproteins • Prevent sperm from fertilizing eggs • 90% success in mammals • Slaughtering • Transferring animals to areas with small populations – Used to reduce numbers of species that have surpassed sustainable a capacity – Ethical issues • Ex. – 1966-1994 16,000 elephants culled into Kruger Park in South Africa to limit growth of population Botanic Gardens • Protect endangered plants • Seeds & Cuttings collected from species in wild – Used to build population in garden – Can be reintroduced into ecosystem if needed • Tissue Cultures and Cloning – Used to produce large # of plants from a few original specimen • Small samples of cells collected • Grown on agar in sterile conditions • Cells divide by mitosis mass of cells created and subdivided for cloning • Cells transferred to medium with plant hormones • Cells grow into stems and roots • Transferred in soil to grow • Reintroduce plants into natural habitats – Fairchild tropical Gardens (MIAMI!) • Sargents Cherry Palm Florida Keys • Seed Banks – Collect and store seeds from many diverse plants in case extinction occurs – Seeds from same species collected from different sites to ensure good proportion from total gene pool – Prevents loss of genetic diversity of our crop plants Roles of Botanic Gardens • Protection of endangered species – Botanic gardens currently cultivate 1/3 of world’s known plant species that have been threatened by: • Environmental degradation • Climate change • Research methods of reproduction and growth – Species cultivated in gardens can be grown in appropriate conditions and propagated • Research conservation methods – Enable plants to be reintroduced to new habitats if original is destroyed • Reintroduce species to habitats where they have become rare/extinct • Educate public – Role of plants in ecosystems and economy • Millennium Seed Bank Seed Banks – The Royal Botanic Gardens at Kew, UK, 2000 – Goal: collect and store seeds from at least 25% of world’s plants by 2025 – Seeds arrive at seed bank and are checked for pests, diseases, viability, dried, and stored in airtight jars • Svalbard Global Seed Vault – Run by government of Norway, started 2008 – Located in Arctic Circle (end of 120m tunnel in side of mountain) • Ideal storage conditions (-18*C) • 2013 over 770,000 seed samples from crops around world – Stores seeds in case there is loss of seeds in a seed bank (duplicate samples kept here) – Seed banks can deposit seeds here and still own rights to those seeds – Applications to use seeds must be filed – Storage of seeds is free Seed Banks • International Rice Institute – Philippines – Hold all rice varieties • International Cocoa Genebank – Trinidad – Has 12,000 cocoa trees banked – Distributed to cocoa producing countries after inspection by University of Reading in UK Storage of Seeds • Orthodox seeds – Seeds that remain viable for 15+ years – Dehydrated to only 5% water – Stored at -15* to -20*C – Little ice crystallization = little chance seeds are damaged • Recalcitrant seeds – Seeds that cannot be dehydrated and frozen – Economically important tropical species • Rubber, coconut palm, coffee, cocoa – Only way to maintain genetic diversity: • Collect seeds and grow many generations • Tissue cultures Issues with Growing Samples from Stored Seeds • Possibility of altering genetic diversity • Problem in small samples of seed from rare plants – Smaller samples of original are taken to test for viability or to grow into plants to increase number of seeds in store – Samples unlikely to contain all genetic diversity in original sample – Solution: • Put as large and diverse a sample as possible into storage • • Controlling Alien Species Alien/invasive species: – Species moved from one ecosystem to another where they were previously unknown – Moved due to: • Humans – Global trading of plants and animals – Unknown transport on ships – Biological control agents (Pest control) – Introduced for sport – Released and/or escaped pets Problems with invasive species: – Prey on native species – Outcompete native species for resources • Food and space • Can lead to extinction of native species – Introduce new pathogens/diseases to native species that have never been exposed to them – Toxic to native species – No natural predators to keep population balanced – Overcrowd/overgrow in areas to prevent resources from reaching native organisms – Damage human health – Damage structures Examples of Alien Species • Indian mongoose, Herpestes auropunctatus – Introduced to Jamaica in 1872 to control rats in cane fields (successfully) – Began to prey on native species • Cane toad – Introduced to Queensland, Australia in 1935 to control insect pest of sugar cane – Breeds rapidly and became a pest itself – Spread across country – Produces toxin that kills animals – Endangered marsupial carnivore (northern quolle, Dasyurus hallucatus) close to extinction – Compete with other amphibians for resources – Prey on chicks of native birds • Burmese pythons – Introduced to Florida Everglades probably by reluctant pet owners who could no longer care for it – Feed on mammals and birds so it became competition for native predators – Humans are the only predator • Rabbits – Introduced in Australia for sport in 19th century – Caused the most loss of biodiversity Examples of Alien Species • Red lionfish, Pterois volitans – Introduced to Caribbean waters – Destroys local coral reefs – Hunting expeditions encouraged and cuisines featuring lion fish being introduced • Water hyacinth, Eichhornia crassipes – Floating aquatic plant that spreads rapidly – Covers entire surface of water – Blocks sunlight so native aquatic plants cannot grow – Leads to reduced oxygen concentration = dead native fish – Habitat for mosquito larvae = vectors for disease effects human health • Japanese knotweed, Fallopia japonica – Vigorous root system – Forces its way up through side walks, roads – Damages structures (concrete buildings, roads, walls)Outcompetes native species for space International Conservation Organizations • CITES – Convention on International Trade in endangered Species of Wild Flora and Fauna • Agreement est. in 1973 by 145 countries to control the trade of endangered species and any products from them • Created an appendices regarding endangered species • Negative aspect desire for organisms on list make them more desirable and increase poaching/hunting International Conservation Organizations • WWF – World Wide Fund for Nature – Best known campaigning groups for wild life, est. 1961 by NGOs (non-governmental organization) – Mission Statement: • “To stop the degradation of the planets natural environment and to build a future in which humans live in harmony with nature” • Goals/asks: – Fund conservation projects – Publicizes environmental issues – Campaigns to save ecosystems from degradation – Campaigns to save species from extinction Restoration of Degraded Habitats • Important to restore areas degraded by human activity OR natural disasters – Large scale or small scale • Example – Mangrove forests • Rich ecosystem • Provides protection for coastline from storms • At risk due to coastal development • Provide Ecosystem services – Reduce coastal erosion » Reduce effects of strong waves during storms – Barrier to rising sea levels » Trap sediment – Nurseries for young fish • Replanting Mangrove project in Sunderbans Delta Region – 26,000 sq. km, India and Bangladesh – Largest mangrove forest n the world – Offers land protection against rising sea levels