chapter13 Flashcards
(26 cards)
Ecosystem services Calculating ecosystem values
Ecosystem services are calculated via:
Direct market value
Indirect use value (e.g. real estate price)
Hypothetical market value (what would people be willing to pay to preserve an ecosystem)
key points of making money off of nature papers
- Global loss of ecosystem services due to land use change is $US 4.3–20.2trillion/yr.
- Ecoservices contribute more than twice as much to human well-being as global GDP.
- Estimates in monetary units are useful to show the relative magnitude of ecoservices.
- Valuation of ecosystem services is not the same as commodification or privatization.
- Ecosystem services are best considered public goods requiring new institutions.
Drawbacks and benefits of this approach?
Do you think the calculation of Ecosystem service value is sound?
Can there also be ecosystem disservices? Examples?
Suppose you want to protect a species or an ecosystem that does not provide such a value. What are examples of such species/ecosystems? Are there other reasons to protect them?
what if a not natural alternative turns out to be cheaper
what if people dont want to pay
what if we cannot afford it
disservice eg wolf eating sheep
mosquitos
life on mars
Small populations
Demographic uncertainty
random fluctuations in demographic variables can have a large effect on small populations
Small populations
Environmental uncertainty
unpredictable variability in environmental conditions affect small populations more than large populations
small populations
Inbreeding depression
A loss of vigor amongst offspring occurring when closely related individuals mate
Genetic problems in small populations
Genetic drif
Random changes in gene frequency within a population resulting from sampling effects, rather than natural selection
important in small populations.
Dynamics of small populations
Minimum viable population size (MVP):
the minimum population size for a rare species to be able to preserve its numbers and survive
MPV is affected by
Genetic diversity
Genetic quality (the presence or absence of “bad” genes)
Environmental instability
Demographic factors
Effective population
An estimate of the size of a population based on the numbers of females and males that successfully breed; generally smaller than the total population
Threats to biodiversity
Overexploitation
Habitat disruption
Global environmental change
Introduced and invasive species
Infectious diseases
Overexploitation:
Removal of individuals or biomass from a natural population at a rate greater than the population is able to match with its own recruitment, thus tending to drive the population towards extinction.
Especially susceptible are large species with low intrinsic reproduction rates
E.g. elephants, whales, rhinocerosses
Habitat destruction
for the building of houses or industry
E.g. the harbour area of Vlissingen used to be a wetland
Habitat fragmentation
E.g. fragmentation of mountainous woodland for skiing area
Habitat degradation due to pollution
E.g. leafy lichens are intolerant to air pollution
Habitat disturbance
E.g. people walking in nesting areas
Global environmental change
The Great Barrier Reef is projected to have disappeared by 2050 due to a combination of warming and acidification
Introduced species
may drive local species to extinction through predation or competition
E.g. the European common shore crab is introduced in the American Westcoast, where it outcompetes local crab species
Introduction of exotic species may also cause extinction of other species
E.g. “Killer weed” Caulerpa taxifolia has infested over 30,000 acres of the Western Mediterranean, causing a great reduction in biodiversity
infectious diseases
E.g. devil facial tumour disease
Threats to communities
Extinction of one species may lead to a cascade of other extinctions
E.g. black-tailed prairie dogs are a keystone species in the Great Plains ecosystem
Conservation of populations
Conservation of single species by Species Management Plans
Estimation of Minimum Viable Population Size is often difficult
E.g. yearly discussion about EU fish quota
Captive breeding
Ex situ conservation
captive breeding, gene and seed banks, zoos and aquaria and all other forms of maintaining species artificially and off-site.
E.g. Arabian orynx only exists in captivity (extinct in the wild)
Critics to captive breeding:
It focuses on a few, charismatic species
Problems due to low genetic diversity
Expensive
Gives false sense of optimism
Not usefull if the habitat no longer exists
Criteria for the establishment of a nature reserve:
Species richness
Endemism
Extend to which biota is endangered
