120°W
100°W
80°W
Emerald Ash Borer (EAB) Detection Likelihood
50°N
50°N
Agrilus planipennis Fairmaire 2013 Positives
30°N
Detection Likelihood
30°N
Positives 2013
Low
Moderate
Moderate High
High
Emerald Ash Borer (EAB) Detection Likelihood 2013 Positives
This product utilizes EAB presence data reported solely from the 2013
field season. The intended purpose was to emphasize site characteristics
associated with infestations in the frontier of the EAB range, which may
not be the same as earlier infestations. These data were included
along with eleven independent variables in a MaxEnt statistical analysis
to generate the Detections Likelihood values. The analysis was limited to
the Ash range and included urban areas. Likelihood values are classified into:
Low, Moderate, Moderate High, and High classes.
120°W
100°W
0 50 100
200
300
400
Miles
Albers Equal Area Conic Projection
500
Map produced by FHTET, IL
Fort Collins, CO on 11-26-2013
File: EAB_Detection_Likelihood_2013_only.mxd
Project: EAB_2013.
80°W
Emerald Ash Borer Agrilus planipennis Fairmaire
Detection Likelihood 2013 Positives Model Summary;
November 26, 2013
The 2013 Detection Likelihood model for the Emerald Ash Borer (EAB), Agrilus planipennis, was produced for the Contiguous 48 United States (CONUS) at a 1 square
kilometer (1 km2) resolution by the U.S. Forest Service, Forest Health Protection, Forest Health Technology Enterprise Team's (FHTET) in collaboration with Animal and Plant
Health Service, Plant Protection and Quarantine (APHIS PPQ). The intended use of the 2013 Detection Likelihood is to inform the 2014 EAB sample design.
This product utilizes EAB presence data reported solely from 2013 field season. The intended purpose was to emphasize site characteristics associated with infestations in
the frontier of the EAB range, which may not be the same as site characteristics associated with earlier infestations. These data were included along with eleven independent variables
in a MaxEnt statistical analysis to generate the Detections Likelihood values. MaxEnt is a non-parametric statistical analysis commonly used for generating species distributions
models from presence only data and pseudo-absence. Pseudo-absence is defined as a species being absent from an area for one of three reasons: 1) the habitat cannot support the
species, 2) the species has not completely filled its geographic niche, or 3) the species is present but was not detected. For a species such as EAB that is still expanding its geographic
range this is an appropriate modeling approach. EAB presence data from 2013 was provided by APHIS PPQ and state cooperators. Independent variables were investigated and
selected to represent where EAB is likely to establish (Table 1). A bias raster, based on the autocorrelation of positive EAB locations, was used to correct for sampling bias. The
MaxEnt bootstrap option was used to generate 100 iterations to develop an average Detection Likelihood model. For display purposes the data were partitioned into four classes
(Table 2).
Table 2: Detection Likelihood Classes
Table 1: Variables used in the Detection Likelihood 2013 Positives MaxEnt Model
Variable
Description and Source
Elevation
Digital Elevation Model (DEM 30m) from National Elevation Dataset (NED) resampled (bilinear interpolation) to 1km
resolution and converted from meters to feet.
Distance to Rest Euclidean distance from Rest Areas (POI Factory 2012 http://www.poi-factory.com/node/14656). Rest Area point
Area
locations were identified as potential introduction locations.
Traffic Volume
Drainage Index
Road Density
Traffic Volume point locations, from across the U.S., were compiled from TrafficMetrix and used to interpolate a Traffic
Volume raster using simple variable distance kriging.
Drainage Index is based on soil taxonomy and drainage classes from SSURGO and STATSGO soil data.
Developed from rasterized 2003 Tele Atlas Dynamp Transportation v. 5.2 layer for each state at 100m. Density was
calculated by summing the number of 100m road pixels within a 1 km pixel.
Housing Density Housing density data developed using the 2000 U.S. census data.
Moisture
Surplus/ Deficit
Distance to
Campground
1, 3, 5 year moisture surplus and deficit for 2011 developed from PRISM climate data (Koch 2011).
Urban Areas
Urban areas within the ash range identified as having a population greater than 100 persons per square mile from the 2000
census (Withrow 2010).
Distance to EAB
Positives
Position
Index
Euclidean distance to all known EAB positive locations from all years prior to 2013. The distance to positive EAB
parameter acts as a dispersal kernel in the model.
Terrain index ranging from 0 (flat areas) to 100 (ridge tops). Low values represent valley bottoms. Position index is
generated on a 7x7 kernel and scales the mean elevation to the surrounding elevation to separate lowlands from uplands.
Euclidean distance from campgrounds identified by federal and state cooperators. Campgrounds were identified as
potential introduction locations.
MaxEnt Value
0 to 0.05
0.05 to 0.25
0.25 to 0.50
0.50 to 1
Likelihood Class
Low
Moderate
Moderate High
High
Contractor Support
Ian Leinwand
John Withrow
Point of Contact
Marla C. Downing
Forest Health Technology Enterprise
Team (FHTET), Forest Health
Protection, USDA Forest Service
2150 Centre’ Ave., Bldg A, Suite 331
Fort Collins, CO 80526-8121
Phone: 970-295-5843
mdowning@fs.fed.us