Description
This folder contains ASCII text raster files describing the pine density model and yearly aerial detection survey (ADS) data for three study areas: Sawtooth (central Idaho, USA), Chelan (north-central Washington, USA) and Northern Colorado (USA). These data supported analyses presented in
Powell, J.A., M.J. Garlick, B.J. Bentz and N.A. Friedenberg. (2017) Differential Dispersal and the Allee Effect Create Power-Law Behavior: Distribution of Spot Infestations During Mountain Pine Beetle Outbreaks. Journal of Animal Ecology.
Each raster is at 30m resolution, and each pixel is a density in a space-separated ascii file. The top five rows of each file are commented using % (Matlab comment) and contain: number of columns in the raster, number of rows in the raster, UTM for horizontal location of lower left corner UTM for vertical location of lower left corner NODATA value
Separate readme files are in each subdirectory. The zipped file contains:
1 PDF: Crabb_RP_93WWW.pdf (Crabb et al. 2012)
1 general readme: MPB_Spot_ASCIIs.txt
Chelan subdirectory: 20 ADS ASCII tab-separated rasters (2401 x 2067, 9.77MB each) of tree per hectare impact (1990-2009) + 1 pine cover raster (ca 2001) + 1 readme.txt file
No. Colorado subdirectory: 10 ADS ASCII tab-separated rasters (9259 x 8924, 160MB each) of tree per hectare impact (2001-10) + 1 pine cover raster (ca 2003) + 1 readme.txt file
Sawtooth subdirectory: 10 ADS ASCII tab-separated rasters (2076 x 1437, 22.9MB each) of tree per acre impact (1995-2004) + 1 pine cover raster (ca 2001) + 1 readme.txt file
Author ORCID Identifier
James A. Powell https://orcid.org/ 0000-0002-0594-0136
OCLC
1078223983
Document Type
Dataset
DCMI Type
Dataset
File Format
.txt
Publication Date
5-9-2017
Funder
USDA Western Wildland Threat Assessment Center
USDA, Cooperative State Research, Education, and Extension Service (CREES)
Publisher
Utah State University
Award Number
USDA Western Wildland Threat Assessment Center 09-JV-11221633-240; USDA, Cooperative State Research, Education, and Extension Service (CREES) SBIR 2009-01116
Award Title
Landscape-Scale Enhanced Mountain Pine Beetle and Climate Change Threat Assessment (Western Wildland) and Forest Pest Risk in Dynamic Landscapes (CREES)
Methodology
Aerial Detection Survey data depicting MPB impact as polygons was converted into ASCII rasters with 30 meter pixels. Pine cover density data from a variety of sources was also projected onto 30 meter scales. Data processing is described in detail in:
Crabb, B.A.; Powell, J.A.; Bentz, B.J. (2012) Development and assessment of 30-m pine density maps for landscape-level modeling of mountain pine beetle dynamics. Res. Pap. RMRS-RP-96WWW. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 43 p. (included in archive).
Scientfic Names
Dendroctonus ponderosae Hopkins
Referenced by
Powell JA, Garlick MJ, Bentz BJ, Friedenberg N. Differential dispersal and the Allee effect create power-law behaviour: Distribution of spot infestations during mountain pine beetle outbreaks. J Anim Ecol. 2018; 87:73–86. https://doi.org/10.1111/1365-2656.12700
Location
48.10246, -120.26881 40.40913, -105.83095 44.10315, -114.88954
Language
eng
Code Lists
MPB - mountain pine beetle
ADS - aerial detection survey
TPH - trees per hectare
TPA - trees per acre
FIA - Forest Inventory Analysis
Disciplines
Ecology and Evolutionary Biology
License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Powell, J. A. (2017). MPB Spot Infestation Data. Utah State University. https://doi.org/10.15142/T31C73
Checksum
ca9d5a9228917224ade348dbfb91977c
Additional Files
Powell_README (6 kB)MD5: 318cbd66a090c1e85307d8efa83103ec
Data_for_MPB_Spot_Paper.zip (158290 kB)
MD5: 5d0020712b09a0d8e5bf5f33c3a45b4b
Comments
Mountain pine beetles (MPB, Dendroctonus ponderosae Hopkins) are aggressive insects attacking Pinus host trees. Pines use defensive resin to overwhelm attackers, creating an Allee effect requiring beetles to attack en masse to successfully reproduce. MPB kill hosts, leaving observable, dying trees with red needles. Landscape patterns of infestation depend on MPB dispersal, which decreases with host density. Away from contiguously impacted patches (low beetle densities), infestations are characterized by apparently random spots (of 1-10 trees). It remains unclear whether the new spots are spatially random eruptions of a locally endemic population or a mode of MPB spread, with spatial distribution determined by beetle motility and the need to overcome the Allee effect. To discriminate between the hypothesis of population spread versus independent eruption, a model of spot formation by dispersing beetles facing a local Allee effect is derived. The model gives rise to an inverse power distribution of travel times from existing outbreaks. Using landscape-level host density maps in three study areas, an independently-calibrated model of landscape resistance depending on host density, and aerial detection surveys (data included in this archive), we calculated yearly maps of travel time to previous beetle impact. Isolated beetle spots were sorted by travel time and compared with predictions. Random eruption of locally endemic populations was tested using artificially-seeded spots. We also evaluated the relationship between number of new spots and size of the perimeter of previously infested areas. Spot distributions conformed strongly to predicted power-law behavior. The spatially random eruption hypothesis was found to be highly improbable. Spot numbers grew consistently with perimeter of previously infested area, suggesting that MPB spread long distances from the boundary via spots following an inverse power distribution. The Allee effect in MPB therefore accelerates, rather than limits, invasion rates, contributing to recent widespread landscape-scale mortality in western North America.