modaria working group 9 population modelling - initial ... · emras ii wg6 star wp5 addressed...
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SCK•CEN
MODARIA Working Group 9
population modelling
- initial planning -
Jordi Vives i Batlle (SCK-CEN), Frédéric Alonzo (IRSN)
19th November 2012
First Technical Meeting of the IAEA Modelling and Data
for Radiological Impact Assessments Programme - MODARIA
IAEA, Vienna
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A bit of history
IAEA programme EMRAS II
sub-group "Population Models and Alternative Methods" formed as part of
Working Group 6 – Biota "Dose Effects Modelling".
13-15 active participants from Belgium, France, Italy, Russia, Japan and other
countries.
to review existing population models, develop generic population models for
radiological assessment, develop a scenario for model application and inter-
comparison.
EC programme STAR
sub-task “Integrate population endpoints into ecological protection criteria” as
part of Work Package 5 –“Ecologically Relevant Low Dose Effects“.
5 active participants from France, Norway, Spain, Belgium and Sweden.
to provide a methodology for extrapolating from measurable test endpoints on
individuals to ecologically relevant impacts on a range of representative
taxonomic groups.
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Different population models and working assumptions
EMRAS II WG6 STAR WP5
Addressed
species
mouse, hare/rabbit, wolf/wild dog,
deer + fish and lobster
14 species covering 4 taxonomic groups
(aquatic and soil invertebrates, fish and
terrestrial mammals)
Life history
description
Population structured in two life stages
(juvenile and adult)
Population structured in age classes
(grouped in egg/embryo, juvenile and
adult stages)
Working
assumptions
Limited population with
carrying capacity of 1000
Non-limiting conditions
Aim Predict effects of chronic low-LET
radiation
Integrate effects of chronic gamma
radiation
Effect data Collection of acute LD50/30 Chronic and acute DR-response curves
Time scale Exposure for 5 y
Recovery for 2 y
Instantaneous projection to population
growth rate
Benchmark
endpoints
- Survival at T = 1, 2, 3, 4 and 5 y
- Recovery time after exposure
- DR causing population extinction
- DR causing the lowest significant
reduction in population growth rate
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EMRAS II results
Time to recover after 5 y exposure (y)
D (Gy/d) Malthus Logistic Leslie
0.01 22 201 30
0.02 41 225 61
0.03 56 241 92
0.04 67 253 122
0.05 76 261 153
Details of this project will be given in a separate presentation on
Wednesday morning.
All work successfully published.
Models have common ground.
Some new questions opened.
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Differences in recovery time (NIRS)
rNdt
dN
Malthus model
K
NrN
dt
dN1
Logistic model
Leslie matrix model
Similar predictions for loss of
survival, but very different
recovery time after exposure!
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1 2 … max p max-1 … p -1
S1 S2 Sp-1 Smax-1 Sp
fp fmax fmax-1
Number of age classes
Survival rates
Fecundity rates
hatching
or birth
maturity
EGG
STAGE
JUVENILE
STAGE
ADULT
STAGE
3 life stages defined:
egg, juvenile and adult 0 0 … fp fp+1 … fmax-1 fmax
S1 0 0 0 0 0 0 0
0 S2 0 0 0 0 0 0
0 0 … 0 0 0 0 0
0 0 0 Sp 0 0 0 0
0 0 0 0 Sp+1 0 0 0
0 0 0 0 0 … 0 0
0 0 0 0 0 0 Smax-1 Smax
Transition matrix
Leslie Matrix approach in STAR – model and parameters
Life cycle
Parameters for the Leslie matrices
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0 0 … fp fp+1 … fmax-1 fmax
S1 0 0 0 0 0 0 0
0 S2 0 0 0 0 0 0
0 0 … 0 0 0 0 0
0 0 0 Sp 0 0 0 0
0 0 0 0 Sp+1 0 0 0
0 0 0 0 0 … 0 0
0 0 0 0 0 0 Smax-1 Smax
Transition matrix
with entries as functions
of dose rate
100
102
104
106
108
0
20
40
60
80
100
120
N. arenaceodentata
Gamma dose rate (µGy h-1
)
% e
ffe
ct o
n R
0
100
102
104
106
108
0
20
40
60
80
100
120
Gamma dose rate (µGy h-1
)
% e
ffe
ct o
n
100
102
104
106
108
0
20
40
60
80
100
120
O. diadema
Gamma dose rate (µGy h-1
)
% e
ffe
ct o
n R
0
100
102
104
106
108
0
20
40
60
80
100
120
Gamma dose rate (µGy h-1
)
% e
ffe
ct o
n
100
102
104
106
108
0
20
40
60
80
100
120
P. heterostropha
Gamma dose rate (µGy h-1
)
% e
ffe
ct o
n R
0
100
102
104
106
108
0
20
40
60
80
100
120
Gamma dose rate (µGy h-1
)
% e
ffe
ct o
n
Effect on fecundity
Effect on survival
Effect on hatching
Combined consequences
for individual R0
and population λ
Example in the marine polychaete Neanthes arenaceodentata
from Lance et al. (2012)
Combination of effects on individuals and consequences for R0 and λ
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Some species recommended as RAPs by the ICRP
Soil Invertebrates
OLIGOCHAETES: Eisenia foetida, Lumbricus terrestris
CRUSTACEAN: Porcelio scaber
Terrestrial Mammals
SMALL MAMMALS: Mus musculus, Rattus norvegicus
LARGE MAMMALS: Canis familiaris, Capra hircus, Sus scrofa
Fish
Poecilia reticulata, Oryzias latipes, Oncorhynchus mykiss
Aquatic Invertebrates
POLYCHAETES: Neanthes arenaceodentata, Ophryotrocha diadema
GASTROPOD: Physa heterestropha
IRSN
UMB
SCK
CIEMAT
14 species covering 4 taxonomic groups
Focused on species with chronic dose response curve(s)
described in FREDERICA
Considered range of wildlife species
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MODARIA Working Group 9
The new MODARIA programme allows continuation and expansion of both
EMRAS II and STAR population modelling tasks, capitalising on new knowledge
and developments.
The new population modelling group will be coordinated by Frederic Alonzo
and Jordi Vives i Batlle.
The first WG9 session will be held on Wednesdays 21st November 2012 during
the MODARIA Technical Meeting. We hope that people involved in population
modelling in radioecology from EMRAS II, STAR or any others, will attend.
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Tentative agenda
On Wednesday morning after the plenary session
Introductions
Brief presentation of Leslie matrix modelling by Frédéric Alonzo
Brief presentation of EMRAS II population modelling intercomparison results by
Jordi Vives
On Wednesday afternoon
Discussion on key issues and challenges in population models
Definition of a realistic working plan for the group
Task allocation and planning of future meetings
Presentation of conclusions in the closing plenary session
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Potential tasks (1)
Development of methodology for population modelling
Analysis and comparison of radiation dose effect models developed for
EMRAS II WG6 and STAR WP5
Address how to validate population models experimentally
Model the uncertainty inherent in population model predictions
Development of conceptual models
to take account of effects data from both acute and chronic radiation
exposures
to capture community-level effects such as radiation-induced predator–prey
imbalances
to integrate more physiological realism using mechanistic approaches
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Potential tasks (2)
Development of a set of population models and databases
Collection of life history parameters and radiation effects datasets
for a limited number of species
Extension to ICRP reference animals and plants
Compilation of a handbook of population models and radiation dose
effect modelling
A monograph like IAEA SRS 19 could be useful
Include a chapter exemplifying physiology-based population models
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Potential burning issues (1)
How can we make population models more useful for regulators?
Can we improve the predictive ability of population dose effects
models for real wildlife situation?
Can models describe populations in realistic ecological conditions
without involving too many parameters?
Can simple models take account of eco-physiological factors such as
food limitation, density-dependence, self-limiting growth etc.?
Can simple experimental systems in well-controlled isolate conditions
help understanding the complicate population responses in the field?
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Potential burning issues (2)
Can radiation effects data from acute exposures be used to calibrate
models in chronic exposure situations?
Are radiation effects data from short-term exposures representative of
field populations exposed over several generations?
Should species be considered in isolation or as part of ecosystems with
trophic predator-prey interactions?
Should models consider potential interactions between radioactive and
non-radioactive substances?
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Acknowledgements
We acknowledge the IAEA for supporting the continuity of population
modelling investigations under the new MODARIA programme.