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Chapter 55

BIOLOGY 1M03 Chapter 55: Chapter 55

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Ben Evans

Chapter55–Biodiversity/ConservationBiology Goals of conservation biology • To offset the biodiversity crisis • To preserve individual species (species diversity) • To sustain ecosystems (ecosystem diversity) • To maintain genetic variability (genetic diversity) Questions probed by conservation biologists • WHAT is happening to the biodiversity? • WHY is it happening? (source?) • WHAT can we do about it? (monitoring and refining the process of helping) Endangered Species Act (ESA) and IUCN (International Union for Conservation of Nature) Classifications: Endangered Species: • is in danger of extinction in all or a significant part of its habitat range • either been poached, manipulated to work, habitat changed, no rebound • worst case scenario Ex. Giant pandas, Gorillas, African elephants, and Asian elephants Threatened Species: • Is likely to become endangered in the future throughout all or a significant part of its range • At risk of becoming endangered Ex. Canadian Lynx, Grizzly bears, Bald eagles Protected Species • Against the law to hunt these species Insert slide Why should Humans have Biodiversity? • Humans should value biodiversity since the loss of species is associated with the loss of genes which represent the loss of genetic potential • Biodiversity should be valued because it represents the sum of all genomes on earth • Protect all biodiversity as it is detrimental to our life Other Values of Biodiversity 1. Resources • agriculture • forestry • aquaculture • animal husbandry (the knowledge of maintenance and care of organisms) • medicine (many medical sources are known from other cultures – ethnobotany) Ex. Rosy Periwinkle is collected in Madagascar o Vincristine is used in the treatment of leukemia o Vinblastin is used in the treatment of Hodgkin’s disease o These drugs have provided over $100 million per year in income to several North American pharmaceutical companies, but unfortunately non of this money has been returned to Madagascar 2. Commercial Value ((is linked to #1) • ecotourism – conservation through ecologically responsible travel • natural resource • harvesting 3. Recreational and Aesthetic Value • camping and hiking • rock climbing and mountain climbing • fishing and bird watching 4. Scientific Value • scientific opportunities • investigation of ecological and evolutionary processes • longitudinal studies year by year • nature programs (documentaries) and movies 5. Self Preservation • air and water purification • detoxification of wastes • moderation of droughts and floods • moderation of weather extremes • protection from harmful ultraviolet radiation • protection from erosion • formation and preservation of fertile soils • nutrient cycling 6. Intrinsic Value • other species have value for their own sake • organisms should have the moral and basic right to exist Why should we save the tropical rainforests? • Although it is only a small, portion of the Earth’s surface, it holds many terrestrial species (hotspot)  very rich in biomes How well do humans understand the complexity of ecosystem? • Biosphere 2: a computer program that was built to test the biodiversity o People was supposed to stay for two years, they stayed in 2 months o Low O2, people lost weight o A red flag that we do not have the ability to survive on our own o We are not close to understand the complexity of the ecosystems o We do not fully understand the complexity of the ecosystems, we still need more knowledge o Biosphere 2 evidence: there are a lot of variables and several integrated components What are some of the problems we face when trying to estimate the total number of species? • We can only estimate the total number of species • As we make estimates, we are losing species that may have never been formally documents or given a taxonomic genus, species classification • Protect keystone species first Centillia • Andean foothills in Ecuador In 1978 o species were catalogued by two naturalists o 90% of the species were endemic plants only found here in all the world o a plant had black leaves, no photosynthesis By 1986 o forest was cleared o most recorded endemics and rare species were extinct o others were never catalogued What are “Centillian Extinctions”? • anonymous extinctions of species that have never been formally taxonomically documented by scientists The main problem • the increase in the size of human populations is associated with the massive declines in other species Causes of Extinction: 1. Habitat destruction o Humans cause the greatest alteration and destruction of habitats o Number one reason for extinctions Ex. Urban development and poor logging practices ▪ American Spotted Owl lost nesting sites and is now endangered 2. Habitat Fragmentation o Habitat destruction causes fragmentation of landscapes o Change adjacent sections of land to areas are separated o Decrease total area leads to species loss o “edge effects”: edges are windy, dry, and weedy  the die back Ex. Small plots of land not large enough to feed army ants ▪ fig. 55.11 experimental evidence for edge effects in fragmented forests Experiment: to prove that the larger the area the better the biodiversity Question: Hypothesis: Null Hypothesis: Image Prediction: Results: 3. Introduction to Exotic Species o Intentional or accidental of non-native an area by humans o Native population being disrupted by a non-native species Ex. Invasive species are destructive ▪ Competition: Purple loose-leaf, Kudzu, Zebra-Mussels ▪ Predation: fire ants ▪ Disease: Dutch elm disease (fungus) 4. Overexploitation of resources and wildlife o Harvesting of animals and plants at levels, which exceed their ability to rebound Ex. Bluefin tuna (over fishing) and African elephant (taking tusks) Easter Island (SE Pacific) European Explores found: • only 1000 island people, island was treeless and shrubless • gigantic stone statues, all facing the ocean • there used to be birds, angiosperms, but they becme extinct Finley and King • analyzed pollen fossils • palm trees had once dominated • decrease in palm tree pollen coincided with the arrival of settlers Steadman: • island fauna had changed Diamond: • deforestation local extinctions ecological “disaster” • no trees for fisheries canoes  soil erosion 5. Disruption of Food Chains and food webs • Extinction of one species (primary extinction) affects anpther species (secondary extinction) etc… Ex. If army ants decrease, then birds that eat army ants decrease 6. Pollution • Pollution of air, water, and land Ex. Industrial pollutants, pesticides, oil spills 7. Global Warming • Predicted that 5.5 C increase in temperature in the next 100 years • Some species may not be able to shift their physiological ranges quickly enough to adapt and survive • Husge impact on adaptation s of species involved Ex. Increased atmospheric carbon dioxide Canadian issuses 55.2 Polar Bear in a Warming Arctic Hot Spot • A relatively small area • Has many threatened and endangered species • Has a large concentration of endemic species • One of the areas of concern of conservation biologists focuses upon protecting the species in hot spots • Tropical forest hot spot in Central Est and West of South America, and Chaparrel Hot Spot in southern Africa, South America, south west Australia (lots of biodiversity) • Conservational biologists focus oupon protecting the species in hot spots Hardin, G (1968) The Tragedy of the Commons
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