气候变化领域集成服务门户(CCPortal): Short-term vegetation loss versus decadal degradation of grasslands in the Caucasus based on Cumulative Endmember Fractions

CCPortal

DOI	10.1016/j.rse.2020.111969
	Short-term vegetation loss versus decadal degradation of grasslands in the Caucasus based on Cumulative Endmember Fractions
	Lewińska K.E.; Hostert P.; Buchner J.; Bleyhl B.; Radeloff V.C.
发表日期	2020
ISSN	00344257
卷号	248
英文摘要	Land degradation affects over one-third of the global land area and is projected to become even more widespread due to climate change and land use pressures. Despite being a critical issue for climate change mitigation, biodiversity conservation, and food security, the detection of the onset, duration, and magnitude of land degradation remains challenging, as is early identification of short-term vegetation loss preceding land degradation. Here, we present a new approach for monitoring both short-term vegetation loss and decadal degradation in grasslands using satellite data. Our approach integrates Spectral Mixture Analysis and temporal segmentation, and analyzes dense time-series of satellite observations in three steps. First, we unmix all available satellite observations and aggregate them into monthly composites. Second, we calculate the annual Cumulative Endmember Fractions and examine their piecewise trends among years to determine the onset, duration, and magnitude of short-term vegetation loss and decadal degradation. Third, we attribute a decrease in the green vegetation fraction with a concomitant increase in either open soil, or non-photosynthetic vegetation. We tested our method mapping short-term vegetation loss and decadal degradation in grasslands in the Caucasus Ecoregion using the 2001–2018 time series of MODIS 8-day reflectance data. We found strong patterns of short-term vegetation loss and decadal degradation, mostly in the eastern part of the Caucasus Ecoregion in areas of desert- and semi-desert natural vegetation. Short-term vegetation loss episodes (3–9 years) were more common and had greater magnitude than decadal degradation (≥10 years), especially in steppe regions. On average, 9.3% of grassland area was subjected annually to either decadal, or short-term vegetation loss. Desiccation, i.e., the shift from green vegetation to dry vegetation, was the most prevalent type of change pathway, with green vegetation loss to open soil coming second. Decadal degradation and short-term vegetation loss rates were the highest in dry areas where the potential natural vegetation is sub-shrub deserts, or halophytic, alluvial, and wet lowland forests. Our findings support known general degradation patterns in the Caucasus Ecoregion, but provide better understanding of ongoing processes, by detecting exact location, timing, and magnitude of changes. More broadly, our method advances the monitoring of grasslands by detecting both decadal degradation and short-term vegetation loss. This flexibility supports adaptive degradation monitoring, aids sustainable land management, and provides new information for carbon stock analyses and biodiversity conservation. © 2020 Elsevier Inc.
英文关键词	Caucasus mountains; Google earth engine; Land degradation; Landsat; LandTrendr; MODIS; Rangelands; Spectral mixture analysis (SMA)
语种	英语
scopus关键词	Arid regions; Biodiversity; Climate change; Conservation; Food supply; Land use; Landforms; Satellites; Time series; Time series analysis; Biodiversity conservation; Climate change mitigation; Flexibility supports; Non-photosynthetic vegetation; Satellite observations; Spectral mixture analysis; Sustainable land managements; Temporal segmentations; Vegetation; biodiversity; climate change; decadal variation; episodic event; grassland; land degradation; land use; mitigation; MODIS; satellite data; segmentation; surface reflectance; time series; vegetation dynamics; Caucasus
来源期刊	Remote Sensing of Environment
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/179202
作者单位	SILVIS Lab, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, United States; Geography Department, Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany; Integrative Research Institute on Transformations of Human-Environment Systems (IRI THESys), Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany
推荐引用方式 GB/T 7714	Lewińska K.E.,Hostert P.,Buchner J.,et al. Short-term vegetation loss versus decadal degradation of grasslands in the Caucasus based on Cumulative Endmember Fractions[J],2020,248.
APA	Lewińska K.E.,Hostert P.,Buchner J.,Bleyhl B.,&Radeloff V.C..(2020).Short-term vegetation loss versus decadal degradation of grasslands in the Caucasus based on Cumulative Endmember Fractions.Remote Sensing of Environment,248.
MLA	Lewińska K.E.,et al."Short-term vegetation loss versus decadal degradation of grasslands in the Caucasus based on Cumulative Endmember Fractions".Remote Sensing of Environment 248(2020).