Maintaining populations in the wild Flashcards
What is MVP?
Minimal viable population
What is PVA?
Population Viability Analysis
MVP is the what?
The product
PVA is the what?
The process
What are the components of Population Viability Analysis?
Population Phenotype
Environment
Population structure and fitness
What are population phenotypes?
Morphology
Physiology
Behaviour
Give an example of morphology
Variation in size, shape and patterns
Give an example of physiology
Metabolism
Reproduction
Disease resistance
Give an example of intra and inter specific behaviour
Courtship
Social
Interactions
Give an example of behavioural distribution
Dispersal
Migration
Habitat selection
What are the components of the environment?
Habitat quantity
Habitat quality
Give an example of the factors in habitat quality
Abundance of resources
Abundance of species
Patterns of disturbance
What are the components of population structure and fitness?
Dynamics of spatial distribution
Age and size
Sex ratio
Growth rate
What types of extinction are there?
Deterministic
Stochastic
Define deterministic
A change of force from which there is no escape. Something essential is removed or introduced
Define stochastic
Results from normal random changes or environmental perturbations
Give an example of a stochastic event
The thinning of a population that doesn’t cause it to become extinct
What is the problem with the thinning of a population?
Increased risk of another random event
Also, if the population has been thinned why may their be an increased risk of extinction?
Lower populations are more likely to be vulnerable
Define viable population size
Smallest number of individuals needed to give a population a high probability of survival in a specified period of time
Give an example of a species that has been studied for a viable population size
The Big Horn Sheep
What was the viable population size of the big horn sheep?
101
Why do certain populations decline?
Genetic problems
Demographic influences
Environmental fluctuations
Give an example of the genetic problems that cause populations to decline
Inbreeding
Genetic Drift
Give an example of the demographic influences that cause populations to decline
Random variations in birth and death rates
Give an example of the type of environmental fluctuations that cause populations to decline
Predations Competition Disease Food supplies Natural catastrophes
In a generation, a population of 500 will lose what percentage of its genetic diversity?
0.1%
In what ways can genetic drift be prevented?
By ensuring connectivity between populations of species
What is an effective population?
50 based on domesticated animals, but basically between 50-500 individuals
Give an example of unequal sex ratio
In elephant seals only one male mates with all of the females
How many populations of the grizzly bear are now in the US?
Six populations in four states due to the Western colonisation
What is the number of grizzly bears currently and past?
From 100,000 to 1,000
What is the effective population size of the grizzly bear and why?
25% because not all individuals can breed
How does this number of effective population affect the grizzly bear?
It can cause a loss in genetic variation
What is inbreeding depression?
The reduced fitness in a given population as a result of the breeding of related individuals
Why is inbreeding depression not a problem in large populations?
In large populations, individuals do not mate with close relatives
What is the result of inbreeding depression?
Weak or sterile offspring and expression of harmful genes
Where is inbreeding more likely?
In smaller populations
Why is inbreeding a cause for concern for rare species?
Threatens their survival
What is outbreeding depression?
Outbreeding depression is a scientific term that refers to when two distant relatives of the same species produce offspring less fit than themselves
What is the potential outcome from a loss of evolutionary flexibility?
Extinction
How can variability in climate effect population sizes?
A wet year could increase plant growth and therefore increase herbivores which in turn could increase carnivores
How can natural catastrophes affect population sizes?
It can eliminate populations
Variability in climate is more likely to affect what population sizes?
Small population sizes, they are more vulnerable
Explain the Vortex Effect
Natural disaster may lower population size. This may lead to inbreeding depression. Meaning more vulnerable to extinction.
Give an example of a species that become victim to the Vortex Effect
Greater Prairie Chicken
Give the population in 1933, and the population in 1989
25,000 in 1933 to 50 in 1989.
What was the reason for the Greater Prairie Chickens decline?
Conversion of prairie to farmland
As a result of translocation of male Greater Prairie Chickens to larger populations what happened?
Increased egg hatching success, and increase in genetic diversity
Rarity is a natural phenomenon based on what three parameters?
Geographical range
Habitat specificity
Population sizes
In terms of the IUCN Red List what does extinct in the wild mean?
Extinct in the wild!
In terms of the IUCN Red List what does critically endangered/ endangered mean?
In danger of extinction if causal factors of decline continue
In terms of the IUCN Red List what does vulnerable mean?
Species that are likely to become endangered if casual factors of decline continue
In terms of the IUCN Red List what does near threatened mean?
Populations that are not endangered of vulnerable, but are at risk
In terms of the IUCN Red List what does least concern mean?
Abundant species
How does the IUCN Red List determine which species goes into which category?
By measurements of species decline and population viability
