Week 2 Questions Flashcards
Define: Population, Deme, Subpopulation, Metapopulation
population: A collection of organisms in the same species that interbreed
deme: Individuals of the same species that have a high likelihood of interbreeding
subpopulation: or a portion of a population in a specific geographic location or as delineated by nonbiological criteria
metapopulation: when a species whose range is composed of more or less geographically isolated patches, interconnected through patterns of gene flow, extinction, and recolonization
population viability
likelihood of persistence of well-distributed population > 100 years
dispersal
one-way movement, typically of young away from natal area
Migration
a seasonal, cyclic movement typically across latitudes or elevations:
a. to track resources or
b. to escape harsh conditions changed by season
home range
movement throughout a known space over a day/week/month to locate resources
functional response
refers to changes in the behaviour of organisms
source populations
sink populations
Source: populations of stable reproductive populations
Sink: habitats predominated by subdominant individuals and young of the year
ecological traps
poor-quality habitat appears better than it is
native species
non-native species
native: a species that is located in its presumed area of evolutionary origin and nonhuman-aided dispersal,
non-native species: (of a person, plant, or animal) not indigenous or native to a particular place
Introducing’ wildlife
re-introducing wildlife
‘augmenting’ wildlife
Introducing’ wildlife: Species or genotypes not known to have existed there previously are established at a site. Species may or may not be native to a broader geographic area
re-introducing wildlife: Reestablishment of species or genotypes historically present at the project site but was extirpated.
‘augmenting’ wildlife: Individuals of a species are added to a site where the species occurs presently—also called restocking
resident wildlife
translocated wildlife
resident wildlife: Species, populations, or genotypes native to a local site. These can be extracted from a local site for onsite restoration or augmentation
translocated wildlife: Genotypes are collected offsite for planting or release at a project site within the species’ natural range.
genetic drift
the change in frequency of an existing gene variant in the population due to random chance
hard release
soft release
hard release: animals are released into the wild without any conditioning at the release site
soft release: captured animals are held in captivity for an extended period
minimum viable population
smallest size population (typically measured in absolute number of organisms rather than density or distribution of organisms) that can sustain itself over time
numerical response
numerical response: refers to absolute changes in the abundance of individuals through changes in recruitment.
Explain the concept of metapopulation. How does it relate specifically to restoring wildlife populations (factoring in dispersal ability)?
- when a species whose range is composed of more or less geographically isolated patches, interconnected through patterns of gene flow, extinction, and recolonization
- occur when environmental conditions or species characteristics retard the complete interchange of reproductive individuals
- there is greater demographic and reproductive interaction among individuals within, rather than among, subpopulations
- Identifying formerly occupied locations is a first step in prioritizing restoration efforts, need to identify:
- the metapopulation structure, and
- estimate of the abundance of individuals within each subpopulation,
- one goal - identify the metapopulation structure and then locate restoration sites to enhance this structure
50-500 rule, and 10-50 generation rule
50–500 rule:
- populations of at least 50 breeding individuals are needed for short-term viability (factoring in environmental and demographic variability) and
- 500 individuals are needed for long-term viability (genetics)
10-50 rule:
- populations persist for 10 generations for environmental / demographic variability (population demography/dynamics*), or
- 50 generations for enhancing genetic variability
Why is density a misleading indicator of habitat quality?
Does not provide information on:
- Reproduction, survival, dispersal rates, etc
How does varying habitat quality affect metapopulation structure?
Because of the metapopulation structure, not all suitable habitats will be occupied at any one time:
o thus, unoccupied habitats must be monitored and conserved for many years,
o monitoring needs an adequate sample size to avoid concluding ‘absence,’
o this can be avoided with adequate sample size and monitoring duration,
o designing a restoration plan depends upon the size and fragility of the population and its habitats, and on project objectives,
o thus, identifying the structure of the population(s) of interest is critical if a restoration project is to be successful.
How does the distribution pattern influence the approach to restoration?
- Many species have a bull’s-eye distribution:
- the greatest areas of abundance are toward the middle of their overall ranges and peripheral portions of the range in marginal conditions
How does an understanding of dispersal influence restoration planning?
- provides information on where to prioritize the restoration
- e.g., breeding locations and natal areas
How does an understanding of migration influence restoration planning?
- animals need food, water, cover, and space, and some animals will travel significant distances to obtain these resources.
How does an understanding of home range influence restoration planning?
- detailed information on what animals use must be gathered to specify the vegetation and special habitat features needed
- Temporal aspect
Why is knowing whether your measured population response is a ‘functional’ or ‘numerical’ response
essential?
Explain the source-sink dynamics of populations and their impact on restorations
- Individuals in sink habitats are maintained by continuous immigration from source habitats.
- the metapopulation dynamic reflects frequent movements due to changing source-sink conditions among the individual populations.
Describe how exotic species can impact restoration activities
- Exotics can quickly negate efforts to enhance native species following restoration
- sometimes native species rely on exotics….
Why would you initiate ‘conservation breeding? (3 goals)
- to provide demographic and genetic support for wild populations,
- to establish sources for founding new populations in the wild,
- to prevent species extinction with no immediate chance of survival in the wild.
What are the main concerns about captive breeding and restoring rare populations (3). Include concerns around genetic bottlenecks
1) Captive breeding is expensive, and translocation is problematic
2) the captive breeding program can induce additional mortality in the already-rare species, BC’s spotted owl
3) it is complex
Genetic bottlenecks:
- genetic manipulation could be required to restore/maintain evolutionary potential
- captive breeding can lead to loss of genetic variation through random drift
What are the five key considerations to consider before augmenting a population?
1) are there two lines of evidence (e.g., genetic, demographic, and behavioural) that support the hypothesis that a severe population bottleneck has occurred?
2) would adding additional animals degrade resource conditions, driving the wild animals to a more rapid extinction?
3) was the population bottleneck due to a disease outbreak (or other specific and known occurrence), and can the source of the problem be eliminated?
4) are there habitat patches nearby to establish a larger population (or metapopulation) rather than a single, isolated population?
5) how should the sex and age composition of an augmentation be structured?
- Why is genetic variability in a population good?
How does conservation breeding compromise this variability?
- genetic variation largely determines the ability of populations to persist through changing environments
- captive breeding selection can eliminate alleles that are maladaptive (faulty adaptations) in the captive situation yet important for survival in the wild,
- random genetic drift can cause the cumulative loss of both adaptive and maladaptive alleles
How does metapopulation structure enhance genetic variability?
Increasesit
- retain greater gene diversity (expected heterozygosity)
- greater allelic diversity than would a single, large (panmictic1) population
Successful reintroduction: characteristics of the source population (3)
i. they may come from a captive population or an existing wild population
ii. given that mortality is high among reintroduced animals
- remove individuals only if the source population is not compromise
- only animals descending from the most prolific lineages
iii. the source population should have high genetic diversity, genetic similarity, and environmental similarity compared to the new population
Successful reintroduction: b. evaluation of the reintroduction site (2)
- reintroduction programs must use high-quality habitat
- you must identify critical factors and their status in the release location
Successful reintroduction: size of the reintroduction population
- For native game species, 20–40 founding animals have been sufficient for success.
- Some recommended that at least 30–50 individuals be released if possible.
The success of any restoration program—rests fundamentally on
the habitat condition and niche of the species in question.
What is the primary cause of failure in reintroductions?
Mortality due to predation is a primary cause of failure in reintroductions
