forest genetic resources training guide tree seed supply chains genetic bottlenecks in the...
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Forest Genetic Resources Training Guide
Tree seed supply chains
Genetic bottlenecks in the restoration of Araucaria nemorosa
David Boshier &Chris Kettle
Forest Genetic Resources Training Guide
Location of New Caledonia
Forest Genetic Resources Training Guide
What are the impacts of human interventions on trees?
13 of the 19 species of Araucaria
Forest Genetic Resources Training Guide
What are the impacts of human interventions on trees?
Forest Genetic Resources Training Guide
A. ruleiendangered
A. muellerilower risk – conservation dependent
Forest Genetic Resources Training Guide
Araucaria nemorosa – critically endangered (IUCN)
monoecious flowers, self-compatible, wind pollinated, wind dispersed
Forest Genetic Resources Training Guide
Forest Genetic Resources Training Guide
A. nemorosa
Forest Genetic Resources Training Guide
Forest Genetic Resources Training Guide
Forest Genetic Resources Training Guide
StudyCompared genetic diversity in plants from
i.cones collected from trees
vs
ii.seed from forest floor
Forest Genetic Resources Training Guide
Where & how should we conserve?
Forest Genetic Resources Training Guide
Production of ripe cones in six natural populations
Population
Code Area (ha)
N Sample size
# of trees >15cm dbh
# of trees with cones
# cones/ trees with cones
Mean dbh (cm)
Minimum dbh of trees with cones (cm)
Kaanua N1 22.68
>1000
25 13 1 2 14.9 16
Vane N2 15.72
>1000
15 8 1 7 25.6 48
New Forest
N3 15.2 >1000
63 45 4 1,2,3,3 18.2 18.5
Mini Nuri N5 1.28 <500 36 22 4 2,2,7,5 18.4 22.5Foret Nord
N6 0.44 93 28 11 5 1,1,1,3,9
17.1 32.7
Natasha’s N7 1.48 <100 62 23 2 2,8 12.9 23.5
Forest Genetic Resources Training Guide
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
• refers to effective population size (Ne) rather than survey numbers (N) – so may need many more!
• in trees Ne smaller than N due to: overlapping generations, dioecy, asynchronous flowering, fecundity differences between individuals
Forest Genetic Resources Training Guide
Genetic diversity, % rare alleles (<0.1), inbreeding coefficients in: adults (A), wild seedlings (W), nursery seedlings (N)
Population
Code Sample type
AE (S.E.) He (S.E.) % rare alleles
FIS Ne
Kaanua N1 A 9.53 (2.46)
0.72 (0.09)
84 0.135*
Kaanua N1 W 8.83 (1.90)
0.71 (0.09)
74 0.194* 30
Kaanua N1 N 2.81 (0.46)
0.46 (0.09)
38 -0.024n.s.
1
Foret Nord
N6 A 6.12 (1.11)
0.65 (0.07)
68 0.009n.s.
Foret Nord
N6 W 5.59 (0.90)
0.62 (0.07)
65 0.168* 11
Foret Nord
N6 N 6.40 (0.87)
0.69 (0.05)
65 0.282* N/C
Forest Genetic Resources Training Guide
Theory
• direct impacts
• decrease pop. size
• increase spatial isolation
• decrease densities
• change local environment
genetic processes
genetic drift
gene flow
mating - inbreeding
selection
Forest Genetic Resources Training Guide
Bottleneck genetic drift
Forest Genetic Resources Training Guide
Your mission
• draw out the seed supply chain
• design a strategy for the collection and use of germplasm
Objective – ensure the maintenance of genetic diversity in the on-going restoration efforts for this threatened species
Forest Genetic Resources Training Guide
How?
• Step 1 - map out the seed/germplasm supply chain for A. nemorosa
• Draw a flow diagram of the chain, from the source to the final user, within the field of restoration (from seed tree to a new plant in its final use).
• The map should identify• players (individuals, institutions) and processes in the chain
(what the players do)• influences of the chain on genetic variation (bottlenecks,
selection, genetic drift)• limiting social factors in the chain (e.g. policies/laws, business,
institutions or resources)
Forest Genetic Resources Training Guide
Forest Genetic Resources Training Guide
How?
• Step 2 – analysis
• What are the genetic risks associated with the actual system of seeds?
• Specific recommendations to improve the situation, dealing with the diversity within the seed system (e.g. practical methods of collecting germplasm that ensure genetic diversity in restoration efforts)
Forest Genetic Resources Training Guide