Samenvatting
Samenvatting Wildlife Ecology & Conservation
Samenvatting van alle colleges, ook van de case study. Bevat oefen examenvragen.
[Meer zien]Voorbeeld 4 van de 40 pagina's
Voorbeeld 4 van de 40 pagina's
In winkelwagengesponsord bericht van onze partner
Voorbeeld van de inhoud
Week 1-3Part I: Importance & Threats
LMon: Importance of Biodiversity
Biodiversity
Types
1. Genetic
2. Species
3. Ecosystem
Diversity causes stability
Current extinction rates
25% of mammals, 13% of birds, >21 000 plants & other organisms
Similar rate as other 5 global mass-extinctions
Main threats
Habitat loss:
Agriculture
Logging
Development (e.g. housing)
Direct mortality:
Hunting (overexploitation)
Invasive species
Dilemma of world population growth
Natural resources increasingly needed -> degradation -> undermines future use
Key factor in species threat: population density of people
Not always a relationship -> less mammals in very dense Europe already, not that many
threatened now
Slowing/halting human pop growth
By
Empowering & educating women
Access to contraception
Problem: economies based on growth
Change in mindset needed
More protected areas
Genetic diversity (GD)
Low GD can reduce:
Pop viability
, Resistance to diseases
Climate change
No evidence as direct cause of extinction
Expected to have negative (indirect) effects in future
Anthropogenic (human caused) threats
Largely determined by:
Income
Pop density
Development activities
Solutions; what can we do?
More substantial conservation efforts
Proactive policies (e.g. shifts in agricultural practices)
Improved land-use planning
Shifting diets
Conservative successes
>31 bird species saved from extinction by conservation programs
Protected areas cover 14% of land surface
Eradication of invasive species
Captive breeding & re-introductions
Future threats
Current + increased but uncertain threat of climate change effects
LTues: Overexploitation
Overexploitation
Oceans
Fishing
Wildlife
Hunting & poaching
Relationship with overfishing (coastal areas without enough fish -> turn to bushmeat,
more hunting)
Forests
Timber extraction & logging
Fuelwood collection & charcoal production
,Tragedy of commons
o Incompletely defined & enforced property rights
o Users do not consider social benefits & costs
o Benefits for individual, negative effects for all
o Harmful effects on 3rd parties: depletion of wildlife
Extent of problem
Overexploitation 1 of 5 main threats
1.5 km2 net forest loss between 2000-2012
Tropics: agriculture & urban expansion
Boreal: fires
Large mammal species: pop decreased after humans entered continent
301 mammal species threatened due to hunting
Less in developed countries (EU), all in developing countries (Africa) -> hunting not
needed & lot of mammals already extinct
Mostly in Asia, Africa & South-America
Larger body mass (kg) -> higher chance of being hunted
Also affects birds (parrots as pets)
Causes of overexploitation
Forests
Timber/logging
Fuelwood/charcoal
Uncontrolled fires
Livestock grazing
Hunting (bushmeat)
Food
Medical products
Ornaments
Pet trade (parrots)
Human induced megafauna extinctions
o Hunting or climate change?
Ongoing debate
Causes increased hunting pressure in tropical forests
o Loss of forest
o Increase in human pop size (people get very old)
o Urbanization
, o Increased access (roads & fragmentation)
o Mobility of hunters
o Modern hunting technologies (weapons)
o Commercialization
o Extractive industries (logging)
Bushmeat hunting on African Savannahs
o Elevated demand (for meat)
o Human encroachment
o Poverty & food insecurity
o No regulation (no legal alternative)
o Political instability
Extinction rates since 1500
o Continental: 6 birds, 3 mammals
Hunting
o Island: 123 birds, 58 mammals
Hunting & predation by invasive species
Parrots => most threatened wildlife species
o Threats:
Pet trade
Habitat loss, fragmentation & degradation
o At risk:
Large bodied, slow breeding
Most species ecologically specialized
Cascading effects of hunting
o Large mammals
Less top-down control
Ecological release small mammals
Loss of predators due to prey depletion
Less seed dispersal -> increased rodent pop
o Small mammals
Less seed dispersal
Less vegetation & invertebrate consumption
Less soil disturbance
Prey depletion
Potential solutions
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