Genetic risk assessment for sampling
and use of native seed: the example
of the UK Native Seed Hub
Michael Way*, Kate Hardwick,
Ted Chapman, Inna Birchenko, Linda Neaves
[email protected]
Context: Millennium Seed Bank Partnership: world flora
Over 100
partners in
50 countries
Context: Millennium Seed Bank Partnership world flora
Sampling strategy
Purpose
Focus
Sampling & use
To combat potentially
catastrophic threats to
human wellbeing by
• safeguarding wild plant
diversity and
• enabling its sustainable
use by global partnership.
Global plant diversity,
especially threatened
and endemic species
Minimum of one large
bulked population sample
per target species.
Samples of 50 seeds
provided for biological
research & education use.
My talk
• The UK Native Seed Hub
• Genetic Risk Assessment
• Worked examples
1. Primula veris
2. Hippocrepis comosa
• Conclusions
• Acknowledgements
UK Native Seed Hub:
-UK habitat loss
Species Rich Grassland
97% loss 1930-1984
(Lawton et al., 2010)
Ancient Woodland
45% loss 1930-1985
Lowland Heath
80% loss 1800-1980
UK Native Seed Hub:
-The habitat restoration challenge
“To make space for nature we need more,
bigger, better and joined up sites to create a
sustainable, resilient and more effective
ecological network for England.” (Lawton et al., 2010)
UK Native Seed Hub:
Maintaining representative genetic diversity:
 Collect representative
population samples
 Maintain diversity by using
robust protocols throughout
storage/multiplication
 Provide guidance on
use of material
UK Native Seed Hub
Sampling strategy
Purpose
Focus
Sampling & use
To supply source-identified
and quality-tested seed
that will contribute to selfsustaining plant
communities in restored
habitats.
Annual and herbaceous
perennial flowering
plants in demand for
grassland creation and
restoration.
How many populations
and from where?
Can material be
translocated within its
native range?
Genetic Risk Assessment
Genetic Risks to consider
Proposed action
Risk to consider
DO NOTHING:
Risk of Inbreeding depression & genetic drift
SAMPLING:
Risk that several population samples chosen at
random across native range will NOT adequately
represent genetic diversity of the species.
Risk of harvesting beyond a safe level
CONSERVATION
TRANSLOCATION:
Risk of Hybridisation, Outbreeding Depression or
Genetic Swamping
Genetic Risk Assessment
Previous large scale risk assessment study
The risk of disruption to existing populations of 151
UK native species was assessed based on:
(1) Dispersal ability
(2) Breeding system
1.
2.
3.
the scale of introduction, in terms of the
overall supply and use of seed
life-history traits known to determine the
partitioning genetic diversity
the degree of intraspecific variation
Walker, K.J., Hodder, K.H., Bullock, J.B., Pywell, R.F. 2004.
A review of the potential effects of seed sowing for habitat re-creation on
the conservation of intraspecific biodiversity.
(3) Phenology
(4) Reproduction
(5) Pollen vector
(6) Life history
(generation time)
(7) Seed weight
(8) Habitat breadth
Genetic Risk Assessment
Framework for estimating Genetic Risk
Genetic risk
Categories
Initial species
selection
60 Species are
proposed for
reintroduction and
shortlisted based on:
•Historic distribution
•Conservation status
•Available estimates
of genetic risks
•Seed availability and
quality
•Public involvement
and interest
Evidence
gathering
Literature review of
species traits and
genetic research
including:
8
38
MODERATE RISK:
• Genetic structure or
highly divergent
populations are
detected
14
HIGH RISK:
• Potential for loss of
genetic diversity is
detected
 molecular genetics
 common garden &
 phylogenetic studies
Identify gaps in
knowledge
29 priority for research
LOW RISK:
• The species is
widespread and
genetically uniform
throughout the
range
•
Not enough
information
Genetic Risk Assessment
Implications of genetic risk categories
Use of material
Genetic risk category
Minimum Sampling of material
use anywhere within
native range
LOW
stratified random sample
from minimum number of
populations
use only within
‘seed zone’
MODERATE
sample from populations
representing ecological and
genetic divisions
use only at origin
HIGH
sample from all populations e.g.
to capture divergent lineages
and adaptations
Worked examples:
1. Primula veris (cowslip)
Evidence:
•Insect pollinated
•Obligate out-breeder
•Thrum & pin flower
morphs
•average dispersal
distance of pollen and
seed is low
•Widely included in
grassland native seed
mixes since 1980s
Image: H Zell CC-BY-SA
Worked examples:
1. Primula veris (cowslip)
Evidence:
• Widespread distribution UK
& Europe
• Genetic diversity of species
is significant
• Populations reduced in
extent and size in UK
• Genetic drift evident in
some small populations
Sampling & use:
Low genetic risk
Distribution of Primula veris at 10 km2
scale, accessed at data.nbn.org.uk, ©
Crown copyright and database rights 2011
Ordnance Survey [100017955]
Worked examples:
2. Hippocrepis comosa (horse shoe vetch)
•Insect pollinated
•Obligate out-breeder
•Limited seed dispersal
• Fragmented distribution
Cytotypes
•Diploid form is an ancient
relict, confined to
inaccessible sites
•Tetraploid more variable
and widespread, prostrate
Worked examples:
2. Hippocrepis comosa (horse shoe vetch)
Uncertainty where the
cytotypes are & likely
negative consequences of
mixing cytotypes:
•Sampling: Moderate risk
of missing some diversity,
so sample from wide range
of environments
•Use: High risk of
disrupting local genetic
diversity, local use only
Distribution of Hippocrepis comosa at 10 km2
scale (data.nbn.org.uk) accessed at
data.nbn.org.uk, © Crown copyright and database
rights 2011 Ordnance Survey [100017955]
Conclusions
• Species-by-species approach is required, and dedicated
genetic studies are recommended
• The low-moderate-high Genetic Risk system allows for better
understanding and easier use in decision-making
• Estimates of Genetic Risk can be made with partial evidence
• Risk based approach can inform sampling and use strategy
• Recommendation not prescription: it’s for the natural
resource managers to make decisions
Acknowledgements
• UK National Tree Seed project: Clare Trivedi, Simon Kallow
• UK Flora project: Stephanie Miles
• Genetic Research and advice: Inna Birchenko, Linda Neaves,
Mike Fay, and partner organisations
• Esmée Fairbairn Foundation
To find out more about the UK Native Seed Hub
visit www.kew.org/seedhub or email [email protected]
The preceding presentation was delivered at the
2015 National Native Seed Conference
Santa Fe, New Mexico April 13-16, 2015
This and additional presentations available at
http://nativeseed.info