Concepts & Definitions Flashcards
Managing endangered species paradigms
- SMALL POP PARADIGM = focus on STOCHASTICITY events that effect pop dynamics and make small pops susceptible to extinction
- PVA to estimate viability over time - DECLINING POP PARADIGM = focus on DETERMINISTIC (non-random) process
- human-caused stressors (habitat loss/frag, overharvest, pollution, climate change)
Forces that drive pop declines aren’t necessarily the same that drive to extinction. Manage for both.
PVA
POPULATION VIABILITY ANALYSIS = use of data/models to estimate persistence over time
- Model pop dynamics
- Include stochasticity (variation in demo parameters)
- Simulate dynamics cumulatively (threshold size, MVP)
E.g. northern spotted owl, modelling showed higher probability of decline with logging
COSEWIC
COM ON STATUS OF ENDANG WILDLIFE IN CANADA
Assessment:
- Doc species diversity & distribution
- Intraspecific diversity (designatable units, geo/gen distinct)
- Decide who needs assessment
- Quantitative criteria (IUCN)
- abundance, range, trend, gen div - Quantitative analysis (PVA, etc)
- Advice Min of Envt/CC
- If listed, immediate protections
- If listed, develop recovery plan
- scientific, inform SARA (political)
- only 18% improve
Failure in protecting endangered species
- jurisdictions
- BC lacks law protecting SAR
- delays/failure to list
- critical habitat not protected
- no prioritization
- little funding
Proposed oversight committee to coordinate planing/action between COSEWIC/SARA & provincial mgmt, monitor, etc
Large carnivores
Threats
- habitat (e.g. lions savannah to ag in Ghana)
- conflict
- prey depletion
- utilization
Vulnerabilities
- range (e.g. wolves/deer Algonquin)
- energy
- low density
- slow life history
- low intrinsic rate of growth
- conflict
- difficult to survey
Umbrella species
Trophic downgrading
Loss of upper trophic consumers changes community structure & ecosystem function
E.g. wolves > deer > forest underbrush
Large carnivore conservation measures
- harvest mgmt
- protected areas (strengthen, expand)
- mitigate conflict
- translocation, reintroduction, captive breeding
Harvest managment
- Avoid overharvest
- Promote societal benefits
- Maintain ecosystem services
Yield = # individuals produced by population (overall growth, not growth rate)
MSY
Fixed-quota vs fixed-effort harvest
MSY
Maximum Sustainable Yield = largest yield taken indefinitely
Harvest management systems
Fixed-quota harvest
- if harvest < recruitment, pop inc to equilibrium
- if harvest > recruitment, pop declines (extinction or stable eq)
- danger if harvest near MSY
Fixed-effort harvest
- proportional quota, % of N
- danger if harvest exceds max intrinsic rate of growth
GRAPHS:
- Pop size vs Yield
- parabola
- harvest = horizontal line (fixed-quota), diagonal line (fixed-effort)
- 1 unstable, 1 stable equilibrium
Harvest management tactics
- season timing/duration
- area regulation (Pop Mgmt Unit)
- control effort = licenses, bag limits, lottery, etc
- age/sex restrictions
- weapon restrictions
- “fair chase” (calls, lights, bait)
Restoration
RESTORATION = act of returning degraded to former condition
ECOLOGICAL RESTORATION = PRACTICE of restoring degraded ecological system
ACTIVE / PASSIVE = manipulation or not
RESTORATION ECOLOGY = process of developing THEORY to guide
- includes niche theory, pop dynamics, energy flow, community structure, etc
Paths to restoration
- Habitat restoration
- wetlands, corridors, fire regimes
- Bonn Challenge
- assumes “they will come” - Population reintroduction/aug
- has threat been removed? - Remove invasive species
- e.g. marbled murrelet & Norway rats on Langara - Restore large predators, ecosystem engineers
Reference conditions
A/biotic conditions, goal
Pre-settlement or Pleistocene rewilding
Difficulties = data, modern acceptance, identify cause, monitor
Alt stable states
Novel ecosystems = diff ecological composition & function due to changing species & envt
Life tables
LIFE TABLE = tool to analyze age-specific vital rates (fecundity, mortality, survival, etc)
Static life table = snapshot
Cohort life table = follow group, fecundity + mortality
Net reproductive rate = sum of survival * fecundity (lx * mx)
R > 1 pop inc
Fecundity
mx = # of female live births per female per unit time
Matrix population model
= bookkeeping of birth/survival using transition probabilities and matrix algebra
Leslie matrices = age-structured model of pop growth
Life history strategies
LIFE HISTORY = set of adaptations that influence survival and fecundity
- lifespan
- survival rate of diff ages
- age at first repro
- # offspring/litter
K-selected = large, slow mature, low fecundity, high survival (competitive at K)
r-selected = small, opposite (maximize pop growth rate, r)