{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,27]],"date-time":"2025-11-27T02:53:36Z","timestamp":1764212016325,"version":"build-2065373602"},"reference-count":42,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2017,5,8]],"date-time":"2017-05-08T00:00:00Z","timestamp":1494201600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Clark County Nevada Desert Conservation Program","award":["CBE603383-14 and CBE604014-16"],"award-info":[{"award-number":["CBE603383-14 and CBE604014-16"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The Southwestern United States desert serves as the host for several threatened and endangered species, one of which is the desert tortoise (Gopherus agassizii). The goal of this study was to develop a fine-scale, remote-sensing-based approach that indicates favorable burrow locations for G. agassizii in the Boulder City (Nevada) Conservation Easement area (35,500 ha). This was done by analyzing airborne LiDAR data (5\u20137 points\/m2) and color imagery (four bands, 0.15-m resolution) and determining the percent vegetation cover; shrub height and area; Normalized Difference Vegetation Index (NDVI); and several geomorphic characteristics including slope, azimuth, and roughness. Other field data used herein include estimates of canopy area and species richness using 1271 line transects, and shrub height and canopy area using plant-specific measurements of ~200 plants. Larrea tridentata and Ambrosia dumosa shrubs were identified using an algorithm that obtained an optimum combination of NDVI and average reflectance of the four bands (IR, R, G, and B) from pixels in each image. The results, which identified more than 65 million shrubs across the study area, indicate that percent vegetation cover from aerial imagery across the site (13.92%) compared favorably (14.52%) to the estimate obtained from line transects, though the LiDAR method yielded shrub heights approximately 60% those of measured shrub heights. Landscape and plant properties were combined with known locations of tortoise burrows, as visually observed in 2014. Masks were created using roughness coefficient, slope percent, azimuth of burrow openings, elevation, and percent vegetation cover to isolate areas more likely to host burrows. Combined, the masks isolated 55% of the total survey area, which will help target future field surveys. Overall, the approach provides areas where tortoise burrows are more likely to be found, though additional ecological data would help refine the overall method.<\/jats:p>","DOI":"10.3390\/rs9050458","type":"journal-article","created":{"date-parts":[[2017,5,8]],"date-time":"2017-05-08T11:45:16Z","timestamp":1494243916000},"page":"458","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Airborne LiDAR and Aerial Imagery to Assess Potential Burrow Locations for the Desert Tortoise (Gopherus agassizii)"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8479-9910","authenticated-orcid":false,"given":"Michael","family":"Young","sequence":"first","affiliation":[{"name":"Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78713, USA"}]},{"given":"John","family":"Andrews","sequence":"additional","affiliation":[{"name":"Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78713, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4068-0648","authenticated-orcid":false,"given":"Todd","family":"Caldwell","sequence":"additional","affiliation":[{"name":"Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78713, USA"}]},{"given":"Kutalmis","family":"Saylam","sequence":"additional","affiliation":[{"name":"Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78713, USA"}]}],"member":"1968","published-online":{"date-parts":[[2017,5,8]]},"reference":[{"key":"ref_1","unstructured":"(2017, May 01). U.S. Endangered Species Act of 1973, Available online: http:\/\/www.nmfs.noaa.gov\/pr\/pdfs\/laws\/esa.pdf."},{"key":"ref_2","unstructured":"U.S. Fish and Wildlife Service (1990). Endangered and threatened wildlife and plants: Determination of threatened status for the Mojave population of the desert tortoise. Federal Register, 55, 12178\u201312191."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"255","DOI":"10.3996\/052015-JFWM-046","article-title":"Enhancing and restoring habitat for the desert tortoise","volume":"7","author":"Abella","year":"2016","journal-title":"J. Fish Wildl. Manag."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1080\/153249802760284793","article-title":"Patton\u2019s tracks in the Mojave Desert, USA: An ecological legacy","volume":"16","author":"Belnap","year":"2002","journal-title":"Arid Land Res. Manag."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"456","DOI":"10.1016\/j.jaridenv.2006.02.019","article-title":"Soil disturbance and hydrologic response at the National Training Center, Ft. Irwin, California","volume":"67","author":"Caldwell","year":"2006","journal-title":"J. Arid Environ."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"854","DOI":"10.1080\/10807030802387457","article-title":"The Apache Longbow-Hellfire missile test at Yuma Proving Ground: Introduction and problem formulation for a multiple stressor risk assessment","volume":"14","author":"Efroymson","year":"2008","journal-title":"Human Ecol. Risk Assess."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1016\/j.jaridenv.2008.12.008","article-title":"The seedbed microclimate and active revegetation of disturbed lands in the Mojave Desert","volume":"73","author":"Caldwell","year":"2009","journal-title":"J. Arid Environ."},{"key":"ref_8","unstructured":"Webb, R.H., Fenstermaker, L.F., Heaton, J.S., Hughson, D.L., and McDonald, E.V. (2009). Natural Recovery from Severe Disturbance in the Mojave Desert. The Mojave Desert: Ecosystem Processes and Sustainability, University of Nevada Press."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"766","DOI":"10.1016\/j.rser.2013.08.041","article-title":"Environmental impacts of utility-scale solar energy","volume":"29","author":"Hernandez","year":"2014","journal-title":"Renew. Sust. Energ. Rev."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1002\/jwmg.816","article-title":"Distance to human populations influences epidemiology of respiratory disease in desert tortoises","volume":"79","author":"Berry","year":"2015","journal-title":"J. Wildl. Manag."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1655\/HERPMONOGRAPHS-D-13-00002","article-title":"Multiple factors affect a population of Agassiz\u2019s Desert Tortoise (Gopherus agassizii) in the northwestern Mojave Desert","volume":"27","author":"Berry","year":"2013","journal-title":"Herpetol. Monogr."},{"key":"ref_12","unstructured":"Szoro, R.C., Siverson, K.E., and Patton, D.R. (1988). Patial distribution of desert tortoises (Gopherus agassizii) at Twentynine Palms, California: Implications for relocations, Management of Amphibians, Reptiles, and Small Mammals in North America."},{"key":"ref_13","first-page":"714","article-title":"Environmental characteristics of desert tortoise (Gopherus agassizii) burrow locations in an altered industrial landscape","volume":"3","author":"Lovich","year":"2000","journal-title":"Chelonian Conserv. Biol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"414","DOI":"10.1643\/CH-06-010","article-title":"Habitat use by desert tortoises (Gopherus agassizii) on alluvial fans in the Sonoran Desert, south-central Arizona","volume":"2","author":"Riedle","year":"2008","journal-title":"Copeia"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Bergen, K.M., Goetz, S.J., Dubayah, R.O., Henebry, G.M., Hunsaker, C.T., Imhoff, M.L., Nelson, R.F., Parker, G.G., and Radeloff, V.C. (2009). Remote sensing of vegetation 3-D structure for biodiversity and habitat: Review and implications for LiDAR and radar spaceborne missions. J. Geophys. Res. Biogeosci., 114.","DOI":"10.1029\/2008JG000883"},{"key":"ref_16","unstructured":"Galik, C.S. (2017, May 01). Contributions of LiDAR to Ecosystem Service Planning and Markets: Assessing the Costs and Benefits of Investment. Available online: https:\/\/nicholasinstitute.duke.edu\/ecosystem\/publications\/contributions-lidar-ecosystem-service-planning-and-markets-assessing-costs-and-benefits."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2881","DOI":"10.5194\/hess-19-2881-2015","article-title":"Laser vision: LiDAR as a transformative tool to advance critical zone science","volume":"19","author":"Harpold","year":"2015","journal-title":"Hydrol. Earth Syst. Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1641\/0006-3568(2002)052[0019:LRSFES]2.0.CO;2","article-title":"LiDAR remote sensing for ecosystem studies","volume":"52","author":"Lefsky","year":"2002","journal-title":"Bioscience"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1569","DOI":"10.1890\/09-1670.1","article-title":"LiDAR remote sensing variables predict breeding habitat of a Neotropical migrant bird","volume":"91","author":"Goetz","year":"2010","journal-title":"Ecology"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"166","DOI":"10.2744\/CCB-1101.1","article-title":"Sample grain influences the functional relationship between canopy cover and gopher tortoise (Gopherus polyphemus) burrow abandonment","volume":"13","author":"Catano","year":"2014","journal-title":"Chelonian Conserv. Biol."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Flaherty, S., Lurz, P.W.W., and Patenaude, G. (2014). Use of LiDAR in the conservation management of the endangered red squirrel (Sciurus vulgaris L.). J. Appl. Remote Sens., 8.","DOI":"10.1117\/1.JRS.8.083592"},{"key":"ref_22","unstructured":"Rundel, P., and Gibson, A.C. (2005). Ecological Communities and Processes in a Mojave Desert Ecosystem: Rock Valley, Nevada, Cambridge University Press."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Heidemann, H.K. (2017, May 01). LiDAR Base Specification. Available online: https:\/\/dx.doi.org\/10.3133\/tm11B4.","DOI":"10.3133\/tm11B4"},{"key":"ref_24","unstructured":"Schenk, T. (2001). Modeling and Analyzing Systematic Errors in Airborne Laser Scanners, Ohio State University."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"874","DOI":"10.3390\/rs2030874","article-title":"Alternative methodologies for LiDAR system calibration","volume":"2","author":"Habib","year":"2010","journal-title":"Remote Sens."},{"key":"ref_26","unstructured":"Shan, J., and Toth, C.K. (2009). LiDAR systems and calibration. Topographic laser Ranging and Scanning, CRC Press."},{"key":"ref_27","unstructured":"Toth, C.K. (2002, January 20\u201323). Calibrating airborne LiDAR systems. Proceedings of the ISPRS Commission II Symposium, Xi\u2019an, China."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1007\/s10651-012-0216-1","article-title":"Random versus stratified location of transects or points in distance sampling: Theoretical results and practical considerations","volume":"20","author":"Barabesi","year":"2013","journal-title":"Environ. Ecol. Stat."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"593","DOI":"10.1002\/env.606","article-title":"Variance estimation for spatially balanced samples of environmental resources","volume":"14","author":"Stevens","year":"2003","journal-title":"Environmetrics"},{"key":"ref_30","unstructured":"Elzinga, C.L., Salzer, D.W., and Willoughby, J.W. (1998). Measuring and Monitoring Plant Populations."},{"key":"ref_31","unstructured":"Greig-Smith, P. (1983). Quantitative Plant Ecology, 3 ed., University of California Press."},{"key":"ref_32","unstructured":"Knight and Leavitt Associates (2017, May 01). Vegetation Data for Desert Tortoise Occupancy Covariate Monitoring Project at the Boulder City Conservation Easement, Available online: http:\/\/www.clarkcountynv.gov\/airquality\/dcp\/Documents\/Library\/symposium\/2016\/9-Vegetation%20Data%20for%20Desert%20Tortoise%20Occupancy%20Covariate%20Monitoring-2016.pdf."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"768","DOI":"10.1890\/0012-9658(2002)083[0768:EROTMD]2.0.CO;2","article-title":"Ecological responses of two Mojave Desert shrubs to soil horizon development and soil water dynamics","volume":"83","author":"Hamerlynck","year":"2002","journal-title":"Ecology"},{"key":"ref_34","unstructured":"Isenburg, M. (2017, March 31). LAStools\u2014Efficient Tools for LiDAR Processing. Available online: http:\/\/lastools.org."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1016\/j.jaridenv.2010.11.005","article-title":"Errors in LiDAR-derived shrub height and crown area on sloped terrain","volume":"75","author":"Glenn","year":"2011","journal-title":"J. Arid Environ."},{"key":"ref_36","unstructured":"Shi, X. (2013). ArcSIE Toolbox for Digital Soil Mapping, v 10.2.105, Dartmouth College."},{"key":"ref_37","first-page":"23","article-title":"A Terrain Ruggedness Index (TRI) that quantifies topographic heterogeneity Intermt","volume":"5","author":"Riley","year":"1999","journal-title":"J. Sci."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1002\/esp.3290120107","article-title":"Quantitative analysis of land surface topography","volume":"12","author":"Zevenbergen","year":"1987","journal-title":"Earth Surf. Process. Landf."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"143","DOI":"10.14358\/PERS.73.2.143","article-title":"An experiment using a circular neighborhood to calculate slope gradient from a DEM","volume":"73","author":"Shi","year":"2007","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/j.rse.2006.02.011","article-title":"LiDAR measurement of sagebrush steppe vegetation heights","volume":"102","author":"Streutker","year":"2006","journal-title":"Remote Sens. Environ."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"584","DOI":"10.1002\/eco.1527","article-title":"What does airborne LiDAR really measure in upland ecosystems?","volume":"8","author":"Luscombe","year":"2015","journal-title":"Ecohydrology"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"342","DOI":"10.3390\/rs70100342","article-title":"Remote sensing of Sonoran Desert vegetation structure and phenology with ground-based LiDAR","volume":"7","author":"Sankey","year":"2015","journal-title":"Remote Sens."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/5\/458\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:35:04Z","timestamp":1760207704000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/5\/458"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,5,8]]},"references-count":42,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2017,5]]}},"alternative-id":["rs9050458"],"URL":"https:\/\/doi.org\/10.3390\/rs9050458","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2017,5,8]]}}}