How many possums and where? The National Possum Model James Shepherd & Mandy Barron.
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Transcript of How many possums and where? The National Possum Model James Shepherd & Mandy Barron.
How many possums and where?
The National Possum Model
James Shepherd & Mandy Barron
How many possums in NZ?
(A = 30.3 million)
How many possums? Who cares?
It’s how possums distributed in space and how their numbers change through time that is important
Possum control decisions
• When? (timing and frequency)• Where? (site prioritisation)
• Need to know current (and predicted) state of possum populations across your sites to make these decisions
LCR possum-TB model
• LCR currently has a useful individual-based possum model that runs at local operational scales
• Also models bovine tuberculosis (TB) within possum population
• Can assess effect of management regimes on possums and TB by simulating possum control
• Possum abundance in model is determined by habitat carrying capacity
Bare Ground
Water
Pasture
Gorse
Narrow-leaved Scrub
Regenerating Forest
Indigenous Forest
Exotic Forest
Unspecified Woody
EcoSat Basic Landcover
Indigenous Forest Composition
“Carrying Capacity” = potential possum density (in absence of control)
Possum TB model – patchy habitat
Possum TB Model (5x5 km)
Bare Ground
Water
Pasture
Narrow-leaved Scrub
Regenerating Forest
Indigenous Forest
Exotic Forest
Unspecified Woody
Scaling up to the national level
• Context is important
• National Possum Model (NPM), national coverage – high spatial detail– all of the information we would use in a
local simulation but NZ-wide!– millions of individuals!
• Not just a static map – dynamic and interactive model– web input & output – online delivery of present and future
population projections
NPM − Why do we want to do this?
• LCR is a national institute, efficient for us to provide a single national predictive tool to land managers – demonstrate our research
• Because we can… spatially-detailed vegetation, ecological, climate and soil layers all exist at national scale AND we now have the computing power
NPM − Why do we want to do this?
• Would provide a central integration point for possum control information– essential for accurate predictions
• Integrating the datasets & technology required for NPM would provide a framework for other pest species such as rats & goats
NPM − Why do we want to do this?
• Web delivery would provide easy user access to present and future pest densities and disease prevalence information
• Potential for the public to see an overview showing control effort and impact (compared with “no control” scenario)
NPM − How would we do this?
• Re-write possum-TB model code, processing distributed amongst a 100 CPU cluster
• Integrate and adapt national layers for vegetation to provide base data to assign carrying capacity
– LCDB 1 & 2 (3)
– Kyoto forestry maps 1990 & 2008 (2012)
– EcoSat BLC & indigenous forest classes
NPM − How would we do this?
• Streamline model input for users to integrate their own control information (area, date and RTC)
• Continue underpinning ecological research– Relationship between land cover & pest
density– Improve model parameters such as home
range distribution, dispersal, probability of disease transmission
NPM − How would we do this?
• Provide user feedback to the underlying science when model predictions differ from reality– Focus future science effort
Photo by Paul Horton
NPM − Results / Output
No Control
NPM − Results / Output
post AHB & DOC control in 2008/09
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
NPM – Web demonstration
Discussion• End-user requirements, ideas
– typical control scenarios– density / RTC thresholds
• Potential problems, data sensitivities• Cost – free?
Photo by Morgan Coleman