The changing contexts of the desertification debate

Herrmann, Stefanie M.; Hutchinson, Chad M.

doi:10.1016/j.jaridenv.2005.03.003

Cited by 163 publications

(120 citation statements)

References 51 publications

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“…It means that for a certain determination of trends by variables with high amplitude of oscillations one needs to analyse a longer time-period than by low-oscillating variables. Unfortunately for trends detection, the vegetation cover in drylands'ecosystem is characterized by high inter-annual variability which is caused by high variance of climatic factors, particularly precipitation (Mainquet, 1999;Herrman and Huttchinson, 2005). However, the length of the time-period analysed in this study (1982 to 2003) was limited through the length of the USGS data archive.…”

Section: Methodsmentioning

confidence: 99%

Inter-Annual Changes in Vegetation Activities and Their Relationship to Temperature and Precipitation in Central Asia from 1982 to 2003

Propastin

Kappas²,

Muratova³

2008

J ENV INFORM

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ABSTRACT. We analyzed inter-annual trends in annual and seasonal vegetation activities in Central Asia from 1982 to 2003 and their correlation to climate variability using the NOAA/AVHRR Normalized Difference Vegetation Index (NDVI) dataset and a gridded climate dataset. The results indicate a significant increase in NDVI with a value of 11.35% over the growing season during the 22-year period. Totalled over the entire vegetated area, about 35% of all pixels exhibited significant upward trend in growing season NDVI. We found that NDVI increase in spring was the main contributor to the general upward trend, the spring NDVI increased in more than 50% of all pixels and showed an average value of 13.58%. Correlation analysis indicated a gradual rise in temperature as the only factor controlling trend in spring NDVI. Significant increase in vegetation activity was also identified for summer season, but its amplitude (9.23%) and comprising area (25.13% of all vegetated pixels) were less than for spring. Downward trends in growing season NDVI occurred in 2.17% of the total vegetated area. The greening trends of spring, growing season and summer NDVI strongly related with the climatic parameters: for each land cover type, we found significant correlation with spring temperature and total precipitation; 75% of all upward trends in growing season NDVI were explained by the combination of these both variables. We found that the NDVI trends and their climatic correlates demonstrate great spatial variability at the scale of individual land cover types and at per-pixel scale and proofed that the land use change caused by the constitutional change in the 1991 has substantial control on the vegetation trends. Increased vegetation growth indicated through the analysis of NOAA AVHRR NDVI time-series suggests an increasing carbon stock in biomass of ecosystems in Central Asia.

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Section: Methodsmentioning

confidence: 99%

Inter-Annual Changes in Vegetation Activities and Their Relationship to Temperature and Precipitation in Central Asia from 1982 to 2003

Propastin

Kappas²,

Muratova³

2008

J ENV INFORM

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“…This complexity partly arises due to an ongoing discussion on the definition of what actually constitutes degradation and how it should be measured (Reynolds et al, 2011). There are many definitions of LD (Herrmann & Hutchinson, 2005;Nicholson, Tucker, & Ba, 1998). For example, the definition by UNCCD refers to LD as the "reduction or loss of the biological or economic productivity and complexity of rainfed cropland, irrigated cropland, or range, pasture, forest and woodlands resulting from land uses or from a process or combination of processes, including processes arising from human activities and habitation patterns" ( § 5, UNCCD, 1994) (Figure 1).…”

Section: Definition Of Ldmentioning

confidence: 99%

The role of Remote Sensing in land degradation assessments: opportunities and challenges

Dubovyk

2017

European Journal of Remote Sensing

119

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Land degradation (LD) is one of the biggest global challenges for the people's livelihoods and environment. Remote Sensing plays an unprecedented role in LD mapping, assessment and monitoring at multiple spatial and temporal scales. Regardless of a big potential of Remote Sensing to support LD studies, there are still quite a few challenges that impede its successful application. This paper provides a logical synthesis of the role of Remote Sensing for LD assessments. First, background information on definition of LD and existing assessment frameworks are provided. This follows with the synthesis of the areas of application of Remote Sensing for LD analysis and a brief review of the major Remote Sensing variables used in LD studies. The paper further argues for multi-scale and cross-scale LD assessments calling for application-oriented solutions and highlighting the need of in situ data for validation of Remote Sensing-based LD maps. This claim is illustrated by an example of a case study in Uzbekistan.ARTICLE HISTORY

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“…The causes and extent of this desertification crisis have been intensely debated, and the debate has evolved in conjunction with major developments in the fields of climate studies, ecology, and social and political sciences (Herrmann and Hutchinson 2005). In the past decade, the increasing availability of remote-sensing observations has sustained the debate, which had hitherto been mostly driven by anecdotal ground-based observations.…”

Section: Regional Backgroundmentioning

confidence: 99%

People and pixels in the Sahel: a study linking coarse-resolution remote sensing observations to land users' perceptions of their changing environment in Senegal

Herrmann¹,

Sall²,

Sy³

2014

E&S

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ABSTRACT. Mounting evidence from satellite observations of a re-greening across much of the Sahel and Sudan zones over the past three decades has raised questions about the extent and reversibility of desertification. Historical ground data that could help in interpreting the re-greening are scarce. To fill that void, we tapped into the collective memories of local land users from central and western Senegal in 39 focus groups and assessed the spatial association between their perceptions of vegetation changes over time and remote sensing-derived trends. To provide context to the vegetation changes, we also explored the land users' perspective on the evolution of other environmental and human variables that are potentially related to the greening, using participatory research methods. While increases in vegetation were confirmed by the study participants for certain areas, which spatially corresponded to satellite-observed re-greening, vegetation degradation dominated their perceptions of change. This degradation, although spatially extensive according to land users, flies under the radar of coarse-resolution remote sensing data because it is not necessarily associated with a decrease in biomass but rather with undesired changes in species composition. Few significant differences were found in the perceived trends of population pressure, environmental, and livelihood variables between communities that have greened up according to satellite data and those that have not. Our findings challenge the prevailing chain of assumptions of the satellite-observed greening trend indicating an improvement of environmental conditions in the sense of a rehabilitation of the vegetation cover after the great droughts of the 1970s and 1980s, and the improvement of environmental conditions possibly translating into more stable livelihoods and greater well-being of the populations. For monitoring desertification and rehabilitation, there is a need to develop remote sensing-based indicators that better reflect the changes in the biophysical environment that matter most to the land users.

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The changing contexts of the desertification debate

Cited by 163 publications

References 51 publications

Inter-Annual Changes in Vegetation Activities and Their Relationship to Temperature and Precipitation in Central Asia from 1982 to 2003

Inter-Annual Changes in Vegetation Activities and Their Relationship to Temperature and Precipitation in Central Asia from 1982 to 2003

The role of Remote Sensing in land degradation assessments: opportunities and challenges

People and pixels in the Sahel: a study linking coarse-resolution remote sensing observations to land users' perceptions of their changing environment in Senegal

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