A new approach for mapping of Biological Soil Crusts in semidesert areas with hyperspectral imagery

Weber, Bettina; Olehowski, Claas; Knerr, Tanja; Hill, Joachim; Deutschewitz, Kirstin; Wessels, Dirk; Eitel, Bernhard; Büdel, Burkhard

doi:10.1016/j.rse.2007.09.014

Cited by 86 publications

(108 citation statements)

References 29 publications

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“…Hyperspectral imaging has been used to detect and monitor infestations of non-native, invasive plants (e.g., Ustin et al 2004;Glenn et al 2005;Mundt et al 2005). Weber et al (2008) used hyperspectral data to map biological soil crusts in South Africa.…”

Section: Developments In Remote Sensorsmentioning

confidence: 99%

Monitoring Protocols: Options, Approaches, Implementation, Benefits

Karl

Pyke²

2017

Rangeland Systems

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Monitoring and adaptive management are fundamental concepts to rangeland management across land management agencies and embodied as best management practices for private landowners. Historically, rangeland monitoring was limited to determining impacts or maximizing the potential of specific land uses-typically grazing. Over the past several decades, though, the uses of and disturbances to rangelands have increased dramatically against a backdrop of global climate change that adds uncertainty to predictions of future rangeland conditions. Thus, today's monitoring needs are more complex (or multidimensional) and yet still must be reconciled with the realities of costs to collect requisite data. However, conceptual advances in rangeland ecology and management and changes in natural resource policies and societal values over the past 25 years have facilitated new approaches to monitoring that can support rangeland management's diverse information needs. Additionally, advances in sensor technologies and remote-sensing techniques have broadened the suite of rangeland attributes that can be monitored and the temporal and spatial scales at which they can be monitored. We review some of the conceptual and technological advancements and provide examples of how they have influenced rangeland monitoring. We then discuss implications of these developments for rangeland management and highlight what we see as challenges and opportunities for implementing effective rangeland monitoring. We conclude with a vision for how monitoring can contribute to rangeland information needs in the future.

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Section: Developments In Remote Sensorsmentioning

confidence: 99%

Monitoring Protocols: Options, Approaches, Implementation, Benefits

Karl

Pyke²

2017

Rangeland Systems

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“…The time-dependent variation in sun-target-sensor geometry was included in the atmospheric correction of the acquired image lines, which was performed with AtCPro [37], a radiative transfer code originally inspired by the formulation of 5S [38], consecutively upgraded with additional features (e.g., [39,40]), and validated in the context of several studies [41][42][43]. AtCPro in its present version 6.0 accounts for atmospheric extinction processes as a function of sensor and terrain elevation and provides corrections for atmospheric absorption, scattering, pixel adjacency and terrain-dependent illumination effects.…”

Section: Hyspex Airborne Hyperspectral Datamentioning

confidence: 99%

The Potential of EnMAP and Sentinel-2 Data for Detecting Drought Stress Phenomena in Deciduous Forest Communities

et al. 2015

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Given the importance of forest ecosystems, the availability of reliable, spatially explicit information about the site-specific climate sensitivity of tree species is essential for implementing suitable adaptation strategies. In this study, airborne hyperspectral data were used to assess the response of deciduous species (dominated by European beech and Sessile and Pedunculate oak) to water stress during a summery dry spell. After masking canopy gaps, shaded crown areas and non-deciduous species, potentially indicative spectral indices, the Photochemical Reflectance Index (PRI), Moisture Stress Index (MSI), Normalized Difference Water Index (NDWI), and Chlorophyll Index (CI), were analyzed with respect to available maps of site-specific soil moisture regimes. PRI provided an important indication of site-specific photosynthetic stress on leaf level in relation to limitations in soil water availability. The CI, MSI and NDWI revealed statistically significant differences in total chlorophyll and water concentration at the canopy level. However, after reducing the canopy effects by normalizing these indices with respect to the structure-sensitive simple ratio (SR) vegetation index, it was not yet possible to identify site-specific concentration differences in leaf level at this early stage of the drought. The selected indicators were also tested with simulated EnMAP and Sentinel-2 data (derived from the original airborne data set). While PRI proved to be useful also in the spatial resolution of EnMAP (GSD = 30 m), this was not the case with Sentinel-2, owing to the lack of adequate spectral bands; the remaining indicators (MSI, CI, SR) were also OPEN ACCESS Remote Sens. 2015, 7 14228 successfully produced with Sentinel-2 data at superior spatial resolution (GSD = 10 m). The study confirms the importance of using earth observation systems for supplementing traditional ecological site classification maps, particularly during dry spells and heat waves when ecological gradients are increasingly reflected in the spectral response at the tree crown level. It also underlined the importance of using Sentinel-2 and EnMAP in synergy, as soon as both systems become available.

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“…Several indices were used to identify and map cyanobacteria-dominated biocrusts [43] and lichen-dominated biocrusts using multispectral remote sensing [55] and hyperspectral imaging [56]. Other studies use different band combinations in different spectral regions for assessing the development of biocrusts [57,58].…”

Section: Biocrust Covermentioning

confidence: 99%

Structural Changes of Desertified and Managed Shrubland Landscapes in Response to Drought: Spectral, Spatial and Temporal Analyses

et al. 2014

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Drought events cause changes in ecosystem function and structure by reducing the shrub abundance and expanding the biological soil crusts (biocrusts). This change increases the leakage of nutrient resources and water into the river streams in semi-arid areas. A common management solution for decreasing this loss of resources is to create a runoff-harvesting system (RHS). The objective of the current research is to apply geo-information techniques, including remote sensing and geographic information systems (GIS), on the watershed scale, to monitor and analyze the spatial and temporal changes in response to drought of two source-sink systems, the natural shrubland and the human-made RHSs in the semi-arid area of the northern Negev Desert, Israel. This was done by evaluating the changes in soil, vegetation and landscape cover. The spatial changes were evaluated by three spectral indices: Normalized Difference Vegetation Index (NDVI), Crust Index (CI) and landscape classification change between 2003 and 2010. In addition, we examined the effects of environmental factors on NDVI, CI and their clustering after successive drought years. The results show that vegetation cover indicates a negative ∆NDVI change due to a reduction in the abundance of woody vegetation. On the other hand, the soil cover change data indicate a positive ∆CI change due to the expansion of the biocrusts. These two trends are evidence for degradation processes in terms of resource conservation and bio-production. A considerable part of the changed area (39%) represents OPEN ACCESSRemote Sens. 2014, 6 8135 transitions between redistribution processes of resources, such as water, sediments, nutrients and seeds, on the watershed scale. In the pre-drought period, resource redistribution mainly occurred on the slope scale, while in the post-drought period, resource redistribution occurred on the whole watershed scale. However, the RHS management is effective in reducing leakage, since these systems are located on the slopes where the magnitude of runoff pulses is low.

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A new approach for mapping of Biological Soil Crusts in semidesert areas with hyperspectral imagery

Cited by 86 publications

References 29 publications

Monitoring Protocols: Options, Approaches, Implementation, Benefits

Monitoring Protocols: Options, Approaches, Implementation, Benefits

The Potential of EnMAP and Sentinel-2 Data for Detecting Drought Stress Phenomena in Deciduous Forest Communities

Structural Changes of Desertified and Managed Shrubland Landscapes in Response to Drought: Spectral, Spatial and Temporal Analyses

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