conservation biology 2 Flashcards
landscape genetics evaluates
impact of landscape on genetic structure and survival
size of patch effects
carrying capacity
edges affect
species fitness
distance and type of matrix (percolation) determines
migration between patches
Isolation can lead to
extinction, but also speciation
When should we interfere?
small population approach: populations should be protected once they are too small- usually associated with a genetic approach
Declining population approach:Populations should be protected once consistently declining in size, usually associated with an ecological approach
Extinction vortex
small pops prone to loss of genetic diversity via genetic drift which leads to inbreeding depression- in turn leads to smaller pops
vortex sequence
reduced n: demographic stochasticity ( variability in pop growth arising from sampling random births and deaths), environ variation, catastrophes
small, fragmented, isolated populations
inbreeding and loss of diversity
reduced adaptability survival and reproduction
Back to the beginning
Loss of genetic variation also problematic because
needed for evolution of responses to climate change
What 2 things always lead to extinction
small pops and low genetic diversity
Greater prairie chickens
Bottle neck effects due to sudden decr in availability of prairie habitat, caused large reduction in pop
Surviving birds low genetic variation, and only 50% of eggs hatched
Chickens genetic rescue
Genetic variation imported by transplanting birds from larger pops
Declining pop rebounded- due to incr variation
captive breeding- ex-situ conservation
breed in captivity and release when conditions are appropriate for wild survival
Dangers of reintroduction
Breeding in captivity causes behavioural and physiological changes, loss of genetic variability- limit eventual settlement success in nature
Intro of exotic pathogens risk
storage- ex-situ conservation
Preserve plants and germplasm that can be distributed when needed
eg Kew gardens holds threatened spcies, millennium seed bank- cyropreserved seeds and plants
PVA
Population viability analysis
PVA assesses combined impacts on extinction risk of
deterministic factors: habitat loss, overexploitation, pollution, introduced species Stochastic events: - demographic -environmental - genetic stochasticity - catastrophes
Demographic stochasticity
natural fluctuations in B and D rates and sex-ratio independent of environ effects
Environmental stochasiticity
Fluctuations in B and D rates and sex-ratio due to fluctuation in environ
Genetic stochasiticity
Inbreeding depression genetic drift, divergence of pops
lambda
finite rate of growth for a discrete pop growth model
Name an organisation which monitors diversity
international union of conservation
uses a set of extinction criteria to evaluate extinction risk
Assignment to a IUCN category done based on
reductions in numbers, total geographical area occupied, numbers of mature reproductive individuals, habitat loss- considered a PVA:
- varies for different taxa
- has distinct conservation implications
3 threatened categories
Critically endangered
Endangered
Vulnerable
Endangered species conservation
Trying to preserve single species threatened with extinction
Umbrella species conservation
When habitat is preserved to meet needs of an ‘umbrella species’, it helps preserve habitat for many other species (primary species serve as protective ‘umbrella’ for others)
eg large species with huge area requirements, pretty ones to win public affection, keystone species
key species
plays crucial role in how the ecosystem functions
Categories of species vulnerable to extinction
PEERWISE
only occur in threatened habitats Economically valuable to humans Don't have experience of disturbance Evolved in isolation within a limited community without human contact Lack long distance dispersal mechanisms Require large home ranges Short lived Low adult survival rae Low genetic variability Low intrinsic growth rate
Conserving what type of areas is a sensible approach
conserving areas that protect many species at once
How could climate change affect biod hotspots
change location
BIggest contributor to biod loss
loss of habitat
What is key to protection of biod (technique)
establishment of protected areas
Argument for large reserves
large, far-ranging animals with low-density populations need extensive habitats
Argument for smaller reserves
more realistic
Slow spread of disease
Reserve design principles based on island biogeography theory
- Large reserves better than small ones
- Single large one better than groups of smaller one of equivalent total area
- Reserves close together better
- Circular reserves better than long thin ones
- Reserves connected by a corridor better
Saving individual species (population approach)
More common in the past but still ongoing
Offered good PR but let too many others go extinct
Conserving whole ecosystems or landscapes
Based on increased awareness of the importance of species interactions (can’t save one without all)
And incr awareness about ecosystem service
benefits from ecoystems- goods and services
Service values new tool
Ecosystem services encompass all the processes through which natural ecosystems and their species help sustain human life
Ecosystems on such a large scale and so complex that they can’t be replicated using technology
Ecosystem services categories
supporting, provisioning, regulating cultural
Supporting services
Underlying support for all services eg PS, soil formation, nutrient cycling
Provisioning services
food, fuel water
Regulating services
Benefits from ecosystem processes that regulate
eg climate, floods, disease, water quality
Cultural services
eg recreation, tourism, ethical values
scales of ecosystem services
global, landscape, community
field, plot or individual person scale
global scale
carbon sequestration (removal ) climate change
Landscape scale
water purification, erosion control
community scale
crop pollination, pest control
Field plot or individual person
local nutrients, disease and pest preventions
Approach to protect a species might conflict with..
alternative profitable use of a land
tragedy of the commons
- people assume ecosystems are free ‘public goods’: leads to overexploitation and ‘selfish’ behaviours
- valuation shows ecosystem service have value of over 33 trillion USD per year
