120°W
100°W
80°W
European Gypsy Moth Lymantria dispar dispar
Combined Introduction Probability for 2014
50°N
30°N
30°N
Combined Introduction
Low (0 - 0.26)
Moderate (> 0.26 - 0.51)
Moderate High (> 0.51 - 0.76)
High (> 0.76 - 1)
Excluded Quarantine and STS Area
The European Gypsy Moth Combined Introduction Probability
surface was created by retaining the maximum value of the
Short and Long Distance Introduction surfaces. Quarantined
counties and the Forest Service, Slow the Spread action area
were excluded from the map.
120°W
50°N
0 50 100
200
300
400
500
Miles
Albers Equal Area Conic Projection
100°W
Forest Health Technology Enterprise Team
Fort Collins, CO on 7-9-2014
File: Gypsy_Moth_combined_Intro.mxd
Project: Gypsy_Moth_SAHM
80°W
European Gypsy Moth Combined Introduction 2014 Summary
Lymantria dispar dispar
The European Gypsy Moth Combined Introduction surface 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 gypsy moth introduction, for use in modeling gypsy
moth persistence. The Combined Introduction surface was created by taking the maximum value of the Short and Long Range Introduction models
(Downing 2014, Cook 2014). Partially quarantined counties in Maine were given a moderate high value of introduction risk since trapping data from
the known infested region in the Northeastern U.S. were not available. 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.
Table 1: Input layers used to create the Gypsy Moth Combined Introduction surface.
Table 2: Risk Assessment classes
Inputs
Short Range
Gypsy Moth
Introduction
Description and Source
Gypsy moth data was acquired from the Forest Service Slow the Spread gypsy moth trapping database. A
General Linear Model (GLM) was developed between the dependent variable (gypsy moth introduction
locations) and the independent variable (distance to known gypsy moth two year persistence locations).
After validating the model on 2013 introduction locations, it was applied using the 2013 introduction
locations to create a predictive surface for gypsy moth short range introductions in 2014 (Downing 2014).
Long Range
Gypsy Moth
Introduction
The Long Range Gypsy Moth Introduction surface was created using Multivariate Adaptive Regression
Spline (MARS) to model the statistical association between known gypsy moth introductions beyond the
known infested area, and various anthropogenic predictors. Gypsy moth introduction data was acquired
from state and federal cooperators and compiled by APHIS (Cook 2014).
Gypsy Moth
Infested and
Quarantined
Counties
A shapefile containing gypsy moth infested and or quarantined U.S. counties for 2013 was provided by
USDA APHIS to represent the area of known gypsy moth infestation.
Cook, G. L., L. F. Kenneway, M. C. Downing, I. I. F. Leinwand, J. R. Withrow, C. Jarnovich, and F. J. Sapio. 2014.
“Gypsy Moth Risk Assessment: Long Range Introduction”, U.S. Forest Service Forest Health Technology Enterprise Team (FHTET)
Forest Health Protection USDA Forest Service.
http://www.fs.fed.us/foresthealth/technology/invasives_lymantria_dispar_riskmaps.shtml
Downing, M. C., I. I. F. Leinwand, J. R. Withrow, G. L. Cook, L. F. Kenneway, C. Jarnovich, and F. J. Sapio. 2014.
“Gypsy Moth Risk Assessment: Gypsy Moth Two Year Persistence”, USDA Forest Service, Forest Health Protection, Forest Health
Technology Enterprise Team (FHTET). http://www.fs.fed.us/foresthealth/technology/invasives_lymantria_dispar_riskmaps.shtml
USDA, 2013. Forest Service National Gypsy Moth Slow the Spread (STS) program. http://www.gmsts.org
Risk Value
0 to 0.26
> 0.26 to 0.51
> 0.51 to 0.76
> 0.76 to 1.0
Risk Class
Low
Moderate
Moderate High
High
Working Group
Downing, Marla C. – USFS FHTET
Leinwand, Ian I. F. – CNT
Withrow, John R. – CNT
Cook, Gericke L. – APHIS PPQ
Kenneway, Lisa F. – APHIS PPQ
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
Point of Contact: Marla C. Downing,
Forest Health Technology Enterprise
Team (FHTET)
Phone: 970-295-5843,
Email: mdowning@fs.fed.us