Ecology: Human Impact & Conservation

1. Ecology: Human Impact & Conservation IB Biology G3 & G4

2. Biological Diversity • Biological Diversity: Evenness and Richness • Richness: the number of different organisms in a particular area (kinds of species) • Evenness: how the quantity of each different organism compares to the others (abundance of kinds of species) Is a community diverse if it is dominated by a single species? Why/why not?

3. Simpson Diversity Index • A measure that takes into account richness and evenness • Formula: D = • Where: • D = diversity index • N = total number of organisms in the ecosystem • n = number of individuals of each species N (N-1) sum of n (n-1)

4. Simpson Diversity Index Example Σ n(n-1) D = 15 (14) 64 D = 3.3 What does this number represent? How can it be used?

5. Reasons for Conserving Biodiversity • Economic • Examples: rainforest soils for crops; pharmaceuticals; ecotourism • Ecological • Loss of diversity could collapse the ecosystem; diversity makes ecosystems less susceptible to invasive alien species; diversity of plant species buffers the effects of increasing greenhouse gasses • Ethical • “We do not inherit the earth from our ancestors, we borrow it from our children” Native American Proverb • Aesthetic • Nature’s beauty inspires art, gives us awe, and is connected to human cultures in countless ways

6. Biological Control • The use of an organism (introduced) to control another organism • Risks: introduced organism may not behave as expected (Cane Toads) • Benefits: introduced organism may be the only control mechanism flexible enough to be effective against another invasive with no predators • Examples • Purple loosestrife (invasive in US and Canada) – controlled by 2 species of beetles (Gallerucella) • Red Invasive Fire Ants (RIFA) (invasive on many continents) – controlled by Phorid flies red fire ants and phorid flies video on NG.com

7. Biomagnification • The process by which chemical substances become more concentrated at each trophic level. [Increase]: 10 million times

8. CFCs and Ozone • In the atmosphere, CFCs (used in refrigerator coolants, propellants, and foam packaging) release chloride ions. • The chloride ions react with ozone (O3) and produce ClO and oxygen gas (O2) • The ClO molecules react with atoms of O to form more O2 and free up the Cl • In this way the CFCs behave like a catalyst that doesn’t get used up and is free to destroy ozone for a century • Depleted ozone layer permits more UV radiation through the atmosphere • UV radiation causes: • Skin cancer, DNA mutation, sunburn, cataracts, reduced biological productivity, and may be related to loss of amphibian biodiversity globally

9. Indicator Species • AKA “the canary in the coal mine” • Organisms sensitive to environmental conditions • Examples: Lichen (air pollutions like lead/mercury), macroinvertebrates (water quality)

10. http://www.people.virginia.edu/~sos-iwla/Stream-Study/Methods/Form.GIFhttp://www.people.virginia.edu/~sos-iwla/Stream-Study/Methods/Form.GIF Biotic Index

11. Biodiversity in a Nature Reserve • Size of the Reserve • Single large or several small sites? Single large better because small sites = small populations (greater chance for extinctions from disease/lack of genetic diversity). Small sites also have more edges (see next). Some organisms have require large territories that can’t overlap. • Edge Effect • Ecology at the edge of an ecosystem is different from the center. Edges can have more sunlight, more wind, less moisture, and fewer trees. Edge organisms may have more competition/fewer resources. Edges are more susceptible to invasive species. • Corridors • Smaller, otherwise isolated habitats, connected by corridors allow organisms to travel between them. Problems include exposure in narrow corridors, invasives, and human/animal interactions around corridors.

12. Management in Conservation Areas • Restoration: attempt to return the land to it’s natural state through various active management techniques • Recovery of threatened species: usually through habitat restoration (which helps all species ,declared threatened or not, who occupy the habitat) • Removal of introduced species: active removal of invasives such as kudzu from the US southern states or leafy spurge in the US western states • Legal protection against development/pollution/hunting • Funding and prioritizing: limited funding creates the need to make choices: • Restore the habitats of all threatened species or just the ones that make the greatest overall impact? • Remove all introduced species, or just invasives?

13. In Situ Conservation • Conservation of species within their natural habitat (where they belong), such as wildlife reserves, national parks, etc… • Includes planning for improvement of biotic and abiotic factors of that habitat • Maintaining habitat (space); defense of target species from predation; removal of invasives; maintaining large populations; maintaining genetic diversity • Allows threatened species to adapt to environment with minimal interference from humans or invasives • Terrestrial reserves are common for in situ conservation, but marine aquatic reserves lag far behind

14. Ex Situ Conservation • Conservation of a species outside of their natural habitat • Necessary if species is unsafe in the natural habitat, has a population too small to make a come-back, or if social/political/economic reasons make habitat protection impossible • Examples: • Captive Breeding Facilities • Botanical Gardens • Seed Banks

15. Captive Breeding • Zoos are the most common, most have large sections dedicated to captive breeding programs, animal husbandry experts, and money from tourism • Techniques • Artificial insemination (when necessary) • Embryo transfer to surrogate mothers • Cryogenics • Human-raised young (when necessary) • Pedigrees (to reduce inbreeding) • Disadvantages: • Captivity-bred organisms can spread disease to wild ones after re-introduction • Captivity-bred organisms lack the in situ learning and survival strategies

16. Botanical Gardens and Seed Banks • 80,000 plant species kept in private gardens, arboretums and botanical gardens all over the world to protect and breed them • Far easier to care for plants than to breed animals • Problem: wild relatives of commercial crops are under-represented. Genes from these plants could infuse longevity into traditionally inbred crop plants (i.e. bananas) • Seed banks are keeping 10,000 to 20,000 plant species seeds in cold, dark conditions to prevent germination (for decades).