Transcript PPT - Forest Genetic Resources Training Guide

Species conservation strategies
Talbotiella gentii: genetic
variation and conservation
David Boshier, Daniel
Dompreh and Mike Swaine
MSD
Bandai Hills
Worobong
Yongwa
Sapawsu
ME
Krobo
100km
WE
Forest Reserves in Ghana and distribution
of Talbotiella gentii
Dompreh, 2008
Records of Talbotiella populations in Ghana
Red dots = Extant populations, Yellow dots = Extinct
populations.
Sapawsu
Yogaga
Bandai
Yongwa
Talbotiella gentii
15 of 28 populations
now extinct
Most of those extinct
are outside reserves
Threats inside and
outside reserves from fires, firewood cutting
Populations range in size from 2-500 adult trees
1982
1990
2005
Damage of
Talbotiella
population at
Krobo mountain
from fire and
fuelwood
exploitation over
23 years
Aburi Botanical Gardens
Conservation alternatives
• Preservation of actual diversity
• Conservation of evolutionary potential
• Mantain options for future generations,
while satisfying present needs
How big is “big enough”?
• 50/500 rule (Franklin 1980)
• 50 - inbreeding depression to acceptable level
• 500 - sufficient for new variation from mutation to
replace that lost by genetic drift
• effective population size (Ne) more critical than
survey numbers (N) - may need 5,000!
• in trees Ne smaller than N due to: overlapping
generations, dioecy, asynchronous flowering,
fecundity differences between individuals
Where should we conserve?
In situ Ex situ
In situ - reserve system of undisturbed,
protected areas within natural distribution
(ecosystem based)
Ex situ - artificial maintenance of populations
outside natural distribution (species based)
Conservation of biodiversity in situ :
trees as a paradigm
• Ideal reserve model
• Emphasis: large, continuous, protected areas
• Limitations: location, size, security, biology:
–
–
–
–
movement of animals
extensive distribution of many species
gene flow between populations
upland, non agricultural areas
essential but not sufficient
Conservation of biodiversity ex situ :
methods and limitations
•Seed banks - problems of regeneration
•Plantations - changes in gene frequencies, few
populations
•Botanical gardens - deficiencies for gene pool
conservation
Conservation of biodiversity ex situ :
methods and limitations
• Useful, but resources limit application to few
species (usually commercial)
• Last possibility holding for highly endangered
species
• Complementary to other approaches
Bottleneck  genetic drift
Table 3 Within population genetic variability in Talbotiella
gentii, estimated by percentage of polymorphic loci for 83
RAPDs polymorphic bands (8 primers)
Population
Abiriwapong
Botriansa
Yongwa
Nayom
Doorkper
Sapawsu
Hospital
Chalet
Ajena
Kuwere
Krobo
Yogoga
Hotel
Boobohene
Oseikrom
Senkyeso
Kwame Addo
Population size
No. of samples
% polymorphic loci
>100
2
>100
39
21
>50
2
>50
>50
16
>20
11
27
20
6
2
3
16
2
13
5
5
8
2
8
6
4
8
5
5
2
2
2
2
16.3
2.1
13.6
5.2
3.9
8.1
0.8
8.4
4.8
3.1
7.7
7.9
4.4
2.1
2.1
2.1
2.1
Figure 3. Effect of geographic distance of pollen
source on initial fruit set in Talbotiella gentii
Talbotiella gentii
each group summarize on wall chart paper or
PowerPoint
Remember
- need a conservation objective
- prioritize actions – resources are limited
list problems by type
- genetic, which pops. too small? which are different?
- other types of problems
which conservation methods - in situ, ex situ, circa situm?
who? will do, what? where?
how will you pay for it?