Remote monitoring of tamarisk defoliation and evapotranspiration following saltcedar leaf beetle attack
Remote monitoring of tamarisk defoliation and evapotranspiration following saltcedar leaf beetle attack
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DOI：
10.1016/j.rse.2008.05.022
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发表时间：
2009-07
影响因子：
13.5
通讯作者：
P. Dennison;P. Nagler;K. Hultine;E. Glenn;J. Ehleringer
中科院分区：
文献类型：
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作者：
P. Dennison;P. Nagler;K. Hultine;E. Glenn;J. Ehleringer
柽柳（Tamarix spp.）已经入侵了整个美国西部的河岸生态系统，包括美国国家公园和纪念碑内的大部分河岸生态系统。最近，盐柏叶甲虫（Diorhabda elongata）被释放作为一种生物控制剂。虽然最初的释放已经监测，目前没有全面的计划，以监测快速蔓延的Diorhabda已导致许多随后释放的县和州机构。需要长期监测tamelik落叶及其对栖息地和水资源的影响。本研究探讨了使用空间分辨率较高的高级星载热发射和反射辐射计（ASTER）数据和空间分辨率较低的中分辨率成像光谱仪（MODIS）数据监测落叶造成的Diorhabda和随后的变化蒸散量（ET）的潜力。2007年夏季，在犹他州东部的一个研究区观察到广泛的柽柳落叶。ASTER归一化差异植被指数（NDVI）显示，只有轻微的变化，2005年和2006年之间，但在2006年和2007年之间的河岸地区发现了显着下降的NDVI。落叶造成的植被指数的下降是明显的，尽管在研究区域内的部分复叶。中分辨率成像光谱仪时间序列数据显示，EVI的绝对下降因地点而异，但在2007年夏季EVI下降的时间早于2001年至2006年的物候模式。落叶造成的ET值估计从ASTER和MODIS数据的减少。中分辨率成像光谱仪估计的ET下降早于往年，虽然每年的ET是没有显着不同的ET在前几年，由于高年与年的变化。检测和监测的挑战，包括在亚像素空间分辨率，时间序列图像的空间配准，图像采集的时间，和变化无关的落叶在非tamberk土地覆盖的tamberk和其他覆盖类型的光谱混合落叶。本文提出的技术的持续发展可能允许监测Diorhabda的传播和评估潜在的水救助造成的生物控制的tamarak。
Tamarisk (Tamarix spp.) has invaded riparian ecosystems throughout the Western United States, including significant portions of riparian ecosystems within U.S. National Parks and Monuments. Recently, the saltcedar leaf beetle (Diorhabda elongata) was released as a tamarisk biocontrol agent. Although initial releases have been monitored, no comprehensive program is currently in place to monitor the rapid spread of Diorhabda that has resulted from numerous subsequent releases by county and state agencies. Long term monitoring of tamarisk defoliation and its impacts on habitat and water resources is needed. This study examines the potential for using higher spatial resolution Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and lower spatial resolution Moderate Resolution Imaging Spectroradiometer (MODIS) data for monitoring defoliation caused by Diorhabda and subsequent changes in evapotranspiration (ET). Widespread tamarisk defoliation was observed in an eastern Utah study area during summer 2007. ASTER normalized difference vegetation index (NDVI) showed only minor changes between 2005 and 2006, but a significant drop in NDVI was found within riparian areas between 2006 and 2007. The decrease in NDVI caused by defoliation was apparent despite partial refoliation within the study area. MODIS time series data revealed that absolute decline in EVI varied by site, but that the timing of EVI decline during summer 2007 was early with respect to phenological patterns from 2001 through 2006. Defoliation caused decreases in ET values estimated from both ASTER and MODIS data. MODIS estimated ET declined earlier than in previous years, although annual ET was not significantly different than ET in previous years due to high year-to-year variability. Challenges to detection and monitoring of tamarisk defoliation include spectral mixing of tamarisk and other cover types at subpixel spatial resolution, spatial coregistration of time series images, the timing of image acquisition, and changes unrelated to defoliation in non-tamarisk land cover over time. Continued development of the techniques presented in this paper may allow monitoring the spread of Diorhabda and assessment of potential water salvage resulting from biocontrol of tamarisk.