HI Geo Ch 14
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For valuing biodiversity, what are the two types of values and what are the differences between them?
- Extrinsic: consumptive (harvested) and non-consumptive (not destroyed/harvested)
- Intrinsic: nature has value in and of itself, important because purely extrinsic reasons could lead to the protection of species believed to be of higher value.
3 types of extinction
- 1. Local/Extirpation: extinct in a specific area.
- 2. Ecological: too few to fulfill its role in the ecosystem.
- 3. Biological: gone forever
Examples of Ecologically extinct animals
mountain lion, great hornbill
What are the direct causes of the depletion of wild species?
- Habitat loss (loss of niche)
- Habitat degradation (quality going down due to pollution) and fragmentation (large forest split by road)
- Introduction of nonnative species (invasive species)
- Pollution (biocides)
- Climate change (biomes retreated further north because temp and rainfall is changing)
- Commercial hunting and poaching
- Sale of exotic pets and decorative plants
- Predator and pest control
What do human activated pressures lead to?
- small, fragmented, isolated populations
- inbreeding (limited gene pool) which leads to diseases, vulnerability
- demographic instability
- decline in population
- extirpation or extinction
Overharvesting is the major cause of endangerment of
Case Study: The Passenger Pigeon
- From numerous to extinct in 100 years
- Uncontrolled hunting
- good to eat
- Feathers made good pillows
- Bones used as fertilizers
- Easy to kill as they flew in gigantic flocks (blocked out the sun)
- nested in long narrow colonies
- Habitat loss to new human settlements
List the COSEWIC's risk categories in increasing order or danger
special concern, threatened, endangered, extirpated, extinct
Examples of species that were subject to predator control
- Carolina parakeet - damaged fruit crops
- Prairie Dogs poisoned to save cows and horses from breaking their legs. Led to decline of black-footed ferret.
- Deer to reduce over-browsing of vegetation
- Wolf on Vancouver Island to increase deer for hunters
- Coyotes in Newfoundland to increase Caribou
- Seals to protect cod
- Cormorants in Lake Erie to protect endangered plants
What is the number one reason responsible for what percent of species listed as endangered in Canada
What types of changes do human demands cause?
- 1. Physical changes: removing important, tangible habitat components (deforestation)
- 2. Chemical changes: degrading habitats so it can't support wildlife (biocides)
How much of the world's wetlands does Canada contain?
Where are the Carolinian forests? Why are they important?
- ecozone in southwestern ON
- support greatest wildlife diversity in Canada
- 40% of animals listed under SARA in this zone
- remaining tracts belong to regional conservation authorities and private landowners
What was the cause of extirpation of Bald Eagles from the Great Lakes region?
pesticide biomagnification of mercury and lead
What is the first and second leading cause of endangerment (%s)
- 1. Habitat Loss 84%
- 2. Invasive Alien Species 40%
What are the characteristics that make species vulnerable to extinction?
- specialized habitats
- migratory species
- limited and local distributions
- valuable species (economic value)
- large body size (Vulnerable to disruption of prey species and bioconcentration; hunted more easily)
- need a large home range
- Small population size
- Not effective dispersers
- Behavioural traits causing susceptibility (flying in front of cars, manatee attracted o motorboats)
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