120°W
50°N
100°W
80°W
European Gypsy Moth Lymantria dispar dispar
Long Range Introduction Probability for 2014
30°N
50°N
30°N
Long Range Introduction
Low (0 - 0.295)
Moderate (> 0.295 - 0.59)
Moderate High (> 0.59 - 0.795)
High (> 0.795 - 1)
Excluded Quarantine and STS Area
The European Gypsy Moth Long Range Introduction Probability
surface was based on the statistical association between known
gypsy moth introductions and various anthropogenic predictors.
Multivariate Adaptive Regression Spline (MARS) was the statistical
modeling technique selected to generate the final map surface along
with six independent predictor datasets. Quarantined counties and
the Forest Service; Slow the Spread action area were also excluded.
100°W
0 50 100
200
300
400
500
Miles
Albers Equal Area Conic Projection
Forest Health Technology Enterprise Team
Fort Collins, CO on 7-9-2014
File: Gypsy_Moth_Long_Range_Intro.mxd
Project: Gypsy_Moth_SAHM
80°W
European Gypsy Moth Long Range Introduction for 2014
Lymantria dispar dispar
The European Gypsy Moth Long Range Introduction model for 2014 was produced for the Contiguous 48 U.S. (CONUS) at a 240 meter
resolution by the U.S. Forest Service, Forest Health Protection, Forest Health Technology Enterprise Team (FHTET) in collaboration with Animal and
Plant Health Service, Plant Protection and Quarantine (APHIS PPQ) staff, U.S. Geological Survey (USGS), and the European Gypsy Moth Advisory
Group. The intended goal is to develop a spatially explicit model representing the probability of long range gypsy moth introduction, based on the
statistical association between known gypsy moth introductions beyond the known infested zone and various anthropogenic predictors. Gypsy moth
survey and detection data was acquired from state and federal cooperators and compiled by APHIS PPQ. Long range introduction data was defined
using a minimum convex polygon encompassing all two-year persistence trap locations from the Forest Service, Slow the Spread database. The
Software for Assisted Habitat Modeling for VisTrails (SAHM: VisTrails 2013), work flow module was used to investigate various modeling techniques
and predictors for developing the Long Range Introduction surface. Multivariate Adaptive Regression Spline (MARS), was the statistical modeling
technique selected to generate the final map surface. Six independent predictor variables were retained in the final Long Range Introduction model
(Table 1). The continuous probability values were partitioned into four classes (Table 2), with the partition between “Moderate” and “Moderate High”
corresponding to the threshold at which model sensitivity equals model specificity. Quarantined counties and the Forest Service, Slow the Spread action
area were excluded from the final map product.
Table 1: Predictors retained in the Long Range Introduction model for 2014, listed in order of model importance.
Predictors
Description and Source
Median House Hold
Income
Traffic Volume - 20
Mile Moving
Window
U.S. Census Bureau, American Commodity Survey. “Past 12 months (2012) median household income” reported on
tract level and joined to 2011 TIGER tracts boundary layer. “NoData” values were reclassed to zero.
Traffic volume data acquired from TrafficMetrix, snapped and interpolated to a road network. Traffic volume was
selected for highways/interstates and queried on directionality of gypsy moth spread (west/south). Within quarantine
bounds, the maximum traffic volume was used regardless of direction. Volumes were interpolated over a 20-mile
moving window to represent multiple highway introductions within urban areas. “NoData” values were reclassed to
zero.
Developed from rasterized 2003 TeleAtlas Dynamap /Transportation v. 5.2 layer for each state at 100 m. Density was
calculated by summing the number of 100 m road pixels within a 1 km pixel.
Road Density
Campground
Distance
Address Forwards
Population Density
Euclidean distance from campgrounds identified by federal and state cooperators. Campgrounds were identified as
potential introduction locations. Campground locations were compiled by APHIS from federal, state, and private data
sources.
Zipcode-level counts of the number of United States Postal Service (USPS) address forwards originating from the
gypsy moth quarantine area to that destination zip code. Forwarding data was compiled by USPS from July 2009 to
July 2011, and provided to USDA/APHIS under a memorandum of understanding. GIS layer created by APHIS PPQ
staff at the Western GIS Hub in Fort Collins.
U.S. Census population density reported by block group.
SAHM: VisTrails 2013. Talbert, Colin, Talbert Marian, Software for Assisted Habitat Modeling (SAHM) package in VisTrails. U.S.
Geological Survey.
Point of Contact: Marla C. Downing, Forest Health Technology Enterprise Team (FHTET),
Phone: 970-295-5843, Email:mdowning@fs.fed.us
Table 2: Risk assessment classes
Risk Value
0 to 0.295
> 0.295 to 0.59
> 0.59 to 0.795
> 0.795 to 1.0
Risk Class
Low
Moderate
Moderate High
High
Working Group
Cook, Gericke L. – APHIS PPQ
Kennaway, Lisa F. – APHIS PPQ
Downing, Marla C. – USFS FHTET
Leinwand, Ian I. F. – CNT
Withrow, John R. – CNT
Jarnovich, Catherine – USGS
Sapio, Frank J. – USFS FTHET
Advisory Group
Chaloux, Paul – APHIS
Lance, David R – APHIS
Liebhold, Andrew – USFS
Man-Son-Hing, Anthony – APHIS
Mastro, Victor C – APHIS
McPherren, Patrick W – APHIS
Spaulding, Julie S – APHIS