200 likes | 303 Views
Identifying Dutch elm disease ‘danger-spots’ on the Isle of Man with an agent-based model Bruce Mitchell a , Joana Barros b , Daniel Wendel c Email a: bruce.birkbeck@ntlworld.com b: j.barros@bbk.ac.uk c: djwendel@gmail.com. Suffolk, 1984. StarLogo TNG - code blocks.
E N D
Identifying Dutch elm disease ‘danger-spots’ on the Isle of Manwith an agent-based model Bruce Mitchell a, Joana Barros b,Daniel Wendelc Email a: bruce.birkbeck@ntlworld.comb: j.barros@bbk.ac.ukc: djwendel@gmail.com
Objective • Is there a relationship between where a beetle cluster originates and the number of agent elms that die? • If so, might that relationship be used to map the island to reveal locations where an infestation might potentially be more or less damaging?
Isle of Man - Relief • Scolytusbeetles can only thrive where elms prosper • Landscape determineselm habitats • On Man, there is an ‘elm-line’ of ca. 160 metres a.s.l.. • Two ranges of hills exceed this elevation, restricting the flow of the disease across the island • In the model, a ‘beetle-line’ was set at an arbitrary 25 % higher (200m) than the elm-line. • The combination of DEM, elm-line and beetle-line places elevation at the model’s centre. • Beetles operating out of any given disease epicentre will find some areas accessible, others out of range.
A single model run … • Sets up tree, beetle, forester, bird agents • ‘Infects’ up to 1.5% of elms with beetles • Runs an elm census at game turn (GT) 0 • Generates a single beetle cluster • Runs a beetle census at GT 60 • Continues to GT 1,000 • Exports results to .csv file • Resets to GT 0 and introduces next run
SL-TNG Output • For each run: • cluster originates in random location; • number of elms surviving to GT1000 varies • .csv run results ported to MapInfo and SPSS for processing, then transferred to ArcGIS Spatial Analyst
Identifying Dutch elm disease ‘danger-spots’ on the Isle of Manwith an agent-based modelBruce MitchellData Visualisation CentreMethodology DirectorateOffice for National Statistics bruce.mitchell@ons.gov.ukJoana Barros Department of Geography, Environment and Development Studies, Birkbeck, University of London, Malet Street, London, WC1E 7HX j.barros@bbk.ac.ukDaniel WendelLead StarLogo TNG DeveloperScheller Teacher Education Program Massachusetts Institute of TechnologyBoston, MA, USA djwendel@gmail.com