Reintroductions Flashcards
What is the important role of captive populations?
- To re-establish or supplement wild populations whilst maintaining genetic diversity in captivity
What must captive populations do when re-establishing wild population?
- Maintain genetic diversity
- Be self-sustaining
What must be done to the habitat for animal species to be reintroduced successfully?
Habitat restoration/ conservation
What are 2 advantages of Reintroduction
- Method of increasing numbers of individuals – prevent extinction
- Increases knowledge of species biology
- If captive breeding can allow for a self-sustaining population, reduces need to take more from the wild
- Can help gain support – financial and political
What are 2 disadvantages of reintroduction
- Initial stock can damage wild population
- Poor facilities for breeding in captivity
- Maintain a large enough population size to prevent genetic drift and loss of variability
- Selection of captive population making them better fit for captivity than wild environment
- Susceptibility to disease – high concentrations of individuals
- Difficult to get some species to breed in captivity
Name a species that is particularly problematic to breed in captivity
Hawksbill Turtle
Takes 25-40 years to reach sexual maturity - has very precise mating rituals and reproductive is determined by seasonality/ weather
What are the steps to re-releasing a species
Feasibility study and background research
Previous reintroductions review
Identify choice of release site and types
Evaluation of reintroduction site
Number of reintroduction sites
Availability of suitable release stock
Release of captive stock
Socio-economic and legal requirements
Planning, preparation and release stages
Post-release activities
Genetic management of released population
how did a captive breeding program save The Mauritius Pink Pigeon?
- Only 10-20 individuals left in 1980
- Initate captive breeding
- Released 1987
by 1995 population recovered and increased up to 50% per year
Define Soft Release of species
A gradual and supported reintroduction to improve the success of animals released into an unfamilliar wild environment
- i.e: acclimitisation
Define Hard Release of species
An initial reintroduction without human support
Name 2 animals that are better at hard releases
Snakes
Iguanas
Name 2 animals that are better at soft releases
Howler monkeys
Primates
What is reinforcement in reintroductions
Adding individuals to an existing population to increase size, genetic diversity and prevent fragmentation
What are 3 positives of reinforcement?
- Increases existing population size
- Increases genetic diversity
- Prevents fragmentation
What are 3 negatives of reinforcement?
- Disease spread
- deleterious genes
- can reduce diversity due to predation or competition
What is translocation of species?
The deliberate movement of species for conservation purposes
Name a species that has benefited for translocation
Seychelles warbler
Howler monkey
What is the dilution effect
When newly introduced populations negatively effect wild populations by causing outbreeding depression
Name 3 things wild environments often select for
Ability to court, mate, breed and develop
Flightiness and fear to humans
Prey capture and predator avoidance
Disease and parasite resistance
How does captivity cause genetic adaptation?
Often rare/ deleterious alleles in the wild become favoured in captivity, causing genetic adaptation
Name 3 ways we can minimise the effects of genetic adaptation in captivity
Minimise:
Number of generations in captivity (gene banks)
The magnitude of selection in captivity
Genetic variations within populations
The size of captive populations
Maximising the proportion of wild immigrants in recent generations
Make captive habitat similar to wild – often difficult if wild habitat is harsh.
What is supportive breeding?
Supportive breeding is the boosting of a wild population’s size by breeding part of the population in captivity and releasing the captive progeny back into the wild
If carried out poorly, what are 3 negative impacts of supportive breeding?
Reduced wild population size
Reduced reproductive fitness
Inbreeding depression
What percentage of reintroduction programmes are successful (Beck et al , 1994)
11%
What other technique can improve the success of reintroductions?
Translocation
Why is data on reintroduction success so scarce?
- Quantitative evaluations of reintroductions are infrequent and often abandoned
- Lack funding
(Muths et al, 2014)
