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Unformatted text preview: d’Ottawa / University of Ottawa M6.2 BIO 3115 Conservation Biology Goal: to estimate the
Population Viability
likelihood of extinction
(population viability) over
Analysis (PVA)
some finite time period, given
certain demographic, habitat
and management parameters.
Q1: Is there a critical
N=20
minimum size below which
the population faces
N=100
imminent extinction? (the
Minimal Viable Population or
N=200
MVP)
Q2: Is there a certain
minimum viable area (MVA) of
habitat needed to support
Time (years)
such a population?
Probability of extinction M6.5
BIO 3115 Université d’Ottawa / University of Ottawa MVP(x, t) is the minimal
viable population size
required to ensure that
the probability of
population extinction
within t years is less
than 1 x (or the
probability of
persistence for t years is
at least x). Often t is
standardized to 100
years, and x to 0.95. Probability of extinction Population
viability analysis N=20
N=100
N=200 Time (years) M6.6
BIO 3115 Université d’Ottawa / University of Ottawa M6.3 The larger the time
period (t) over which
extinction is assessed,
the larger the estimated
MVP (for constant x)
The larger the
persistence probability
(x), the larger the
estimated MVP (for
constant t) x constant Time period (t)
Estimated MVP The effects of time
and extinction
probability on MVP Estimated MVP BIO 3115 Conservation Biology t constant
Persistence probability (x)
M6.7 BIO 3115 Université d’Ottawa / University of Ottawa MVP and extinction forces Characteristics of the
population or its
environment which tend
to “push” the population
towards extinction, that
is, decreases the
likelihood of population
persistence (increase
extinction risk).
The larger the sum of
these forces, the larger
the MVP. MVP
Strong Persistence Sum of extinction
forces Weak MVP/Persistence
M6.8
BIO 3115 Université d’Ottawa / University of Ottawa M6.4 BIO 3115 Conservation Biology Estimating Minimal Viable
Populations 3 approaches: Empirical determination of the size of
populations that have persisted for a known
period following isolation Through modeling population demography
(based on r, per capita population growth rate,
and V(r) due to demographic and environmental
influences Determine the minimum population required to
maintain most of the original genetic variability. M6.9
BIO 3115 Université d’Ottawa / U...
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This document was uploaded on 03/11/2014 for the course BIO 3115 at University of Ottawa.
 Winter '14
 ScottFindlay
 Conservation Biology, Evolution

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