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Mark A Drummond

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These data were created to describe the causes of land cover change that occurred in the Interior Highland region of the United States for the time intervals of 2001 to 2006 and 2006 to 2011. This region, which covers approximately 17.5 million hectares, includes portions of the U.S. states of Arkansas, Missouri, Oklahoma, and Kansas. Most of the area is covered by gently rolling hills of forests and pastureland. Two raster maps were created at a 30-meter resolution showing the causes of land change using automated and manual photo interpretation techniques. There were 30 categories of land change causes (i.e., forest harvest or surficial mining) discovered over the Interior Highlands. These categories can be used...
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The dataset was generated to describe historical land-use and land-cover (LULC)for the northern Colorado urban Front Range (which includes the cities of Boulder, Fort Collins, Greeley, and Denver) for an area covering approximately 1,023,660 hectares. The Front Range urban landscape is diverse and interspersed with highly productive agriculture as well as natural land cover types including evergreen forest in the Rocky Mountain foothills and Great Plains grassland. To understand the dynamics of urban growth, raster maps were created at a 1-meter resolution for each of four time steps, nominally 1937, 1957, 1977, and 1997. In total, 8 to 38 LULC classes were identified using manual interpretation techniques, aerial...
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The dataset was generated for the South Central Plains EPA level III ecoregion which extends through eastern Texas, northwestern Louisiana, southwest Arkansas, and a small portion of southeastern Oklahoma covering approximately 15.2 ha. Contained in the data set are land change causes that occurred between 2001 to 2006 such as forest harvest, surficial mining, and cropland expansion. Only those pixels (30-meter resolution) that have changed during the time period have their cause classified, otherwise no change is indicated between 2001 and 2006. In general, the process to create the data combined an automated and manual interpretation approach of spatial data to correctly identify land change causes. In the approach,...
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The decline of the iconic monarch butterfly in North America has motivated research on the impacts of land use and land cover (LULC) change and climate variability on monarch habitat and population dynamics. We investigated spring and fall trends in LULC, milkweed and nectar resources over a 20-year period, and ~30 years of climate variables in Mexico and Texas, a key region supporting spring and fall migration during monarchs annual life cycle. We estimated a 2.9% decline in milkweed in Texas, but little to no change in Mexico. Fall and spring nectar resources declined <1% in both countries. Vegetation greenness increased in both the fall and spring in Mexico while the other climate variables, for both countries,...
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These data were created to describe the causes of land cover change that occurred in the Lower Rio Grande (LRG) Valley and Alluvial Floodplain ecoregions of Texas for the time intervals of 2001 to 2006 and 2006 to 2011. The study area covers approximately 600,000 hectares at the southernmost tip of Texas and is one of the fastest growing regions in the United States. Some of the largest cities in the area include Brownsville and Harlingen, Texas. Two raster maps showing the causes of land change were created at a 30-meter resolution using automated and manual photo interpretation techniques. There were 26 categories of land change causes (for example, urban expansion or surficial mining) identified across the LRG...
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