Mapping the dynamics of eastern redcedar encroachment into grasslands during 1984–2010 through PALSAR and time series Landsat images
| Autor: | George L. Geissler, Nicholas I. Cejda, Jinwei Dong, Jie Wang, Geli Zhang, Xiangming Xiao, Yuanwei Qin, Russell Doughty, Brian Alikhani |
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| Rok vydání: | 2017 |
| Předmět: |
Driving factors
Biogeochemical cycle Watershed 010504 meteorology & atmospheric sciences Phenology 0211 other engineering and technologies Wildlife Soil Science Geology 02 engineering and technology Land cover 01 natural sciences Geography Habitat Computers in Earth Sciences 021101 geological & geomatics engineering 0105 earth and related environmental sciences Woody plant Remote sensing |
| Zdroj: | Remote Sensing of Environment. 190:233-246 |
| ISSN: | 0034-4257 |
| DOI: | 10.1016/j.rse.2016.12.025 |
| Popis: | Woody plant encroachment of eastern redcedar (Juniperus virginiana L., hereafter referred to as “red cedar”) into native grasslands in the U.S. Southern Great Plains has significantly affected the production of forage and livestock, wildlife habitats, as well as water, carbon, nutrient and biogeochemical cycles. However, time series of red cedar maps are still not available to document the continuously spatio-temporal dynamics of red cedar encroachment across landscape, watershed and regional scales. In this study, we developed a pixel and phenology-based mapping algorithm, and used it to analyze PALSAR mosaic data in 2010 and all the available Landsat 5/7 data during 1984–2010 with the Google Earth Engine (GEE) platform. This pilot study analyzed 4233 images covering > 10 counties in the central region of Oklahoma, and generated red cedar forest maps for 2010 and five historical time periods: the late 1980s (1984–1989), early 1990s (1990–1994), late 1990s (1995–1999), early 2000s (2000–2004), and late 2000s (2005–2010). The resultant maps for 2010, the late 2000s, early 2000s, and late 1990s were evaluated using validation samples collected from Google Earth's high-resolution images and geo-referenced field photos. The overall (producer and user) accuracy of these maps ranged from 88% to 96% (88%–93%, and 96%–99%). The resultant maps clearly illustrated an increase in red cedar encroachment within the study area at an annual rate of ~ 8% during 1984–2010. These maps can be used to support additional studies on the driving factors and consequences of red cedar encroachment. This study also demonstrated the potential to trace the historical encroachment of red cedar into grasslands using time series Landsat images and PALSAR data. |
| Databáze: | OpenAIRE |
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