Relating canopy reflectance to the vegetation composition of mountainous grasslands in the Greater Caucasus

Magiera, Anja; Feilhauer, Hannes; Otte, Annette; Waldhardt, Rainer; Simmering, Dietmar

doi:10.1016/j.agee.2013.05.017

Cited by 13 publications

(4 citation statements)

References 78 publications

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“…We found no indication of the application of mineral fertilizers in our study region. For a detailed description of the study area, see Nakhutsrishvili (1999), Magiera et al (2013), and Tephnadze et al (2014).…”

Section: Study Areamentioning

confidence: 99%

Mapping Plant Functional Groups in Subalpine Grassland of the Greater Caucasus

Magiera

Feilhauer

Waldhardt

et al. 2018

Mountain Research and Development

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Section: Study Areamentioning

confidence: 99%

Mapping Plant Functional Groups in Subalpine Grassland of the Greater Caucasus

Magiera

Feilhauer

Waldhardt

et al. 2018

Mountain Research and Development

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“…As the expected spectral separation between flowers and leaves was expected to be greater than many of these applications, particularly spectral separation between leaves of different species (Gross and Heumann, 2014), a more complex approach to quantify subtle spectral differences was not warranted. (Vaiphasa et al, 2005) 350 -2151 480   (Adam and Mutanga, 2009) 350 -2500 459    (Pu, 2009) 350 -2500 394  ANN 1 LDA 2 (Kisevic et al, 2011) 350 -1050 Unknown   (Ullah et al, 2012) 2500 -14000 455   (Magiera et al, 2013) 325 -1075 240   (Bao et al, 2017) 350 -1050 153   (Al-Ahmadi et al, 2018) 480 -2400 160   For this staged approach to assess spectral separation initially, the spectra were divided into three groups: Flowers (F), Leaves (L) and Ground (G). The range and mean of these groups are shown in Figure 3.…”

Section: Spectral Separation Of Corymbia Calophylla Flowersmentioning

confidence: 99%

Honey Crop Estimation From Space: Detection of Large Flowering Events in Western Australian Forests

Campbell

Fearns

2018

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Abstract. Recent studies have shown that in the spectral space there is often a better spectral separation between leaves and flowers and even between flowers of different species than between leaves of different species. In this study we assess the ability of satellite remotely sensed data to detect the flowering of Red Gum trees (Corymbia calophylla) in Western Australia, the state’s largest annual honey crop. Spectroradiometer measurements of flowers, leaves and groundcover from Red Gum forests were subjected to ANOVA analysis, which showed that flowers are spectrally different to their environment for 92% of the wavelengths between 350nm and 1800nm. A more detailed assessment, using the JM Distance calculation, showed that the spectra can be reliably separated using 10% of the wavelengths, with peak separation between 518nm and 557nm. To assess the ability of satellite-borne sensors to detect the presence of flowers, the spectroradiometer data were convolved with satellite instruments’ response curves to create synthetic remotely sensed datasets on which JM Distance analysis was performed. MODIS blue bands achieved a median JM Distance of greater than 1.9 and therefore should be able to detect the presence of flowers from the environment. Further assessment showed that the shortest wavelength bands for MODIS, VIIRS and Sentinel 3 all occur where the flower spectra have lower reflectance than their natural background. A sensitivity analysis of percentage flower cover for a pixel showed that the highest sensitivity was obtained by dividing the band closest to 520nm by the shortest wavelength band for data from these three sources. The MODIS band 10/band 8 metric was tested for its ability to detect flowers in real-world data using 15 years of qualitative honey harvest data from one apiary site as a proxy for flower density. This test was successful as, while there was some overlap between good, moderate and poor years, the poor years could be separated from the other years with nearly 80% accuracy.

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“…These transitions have been reflected in the land-cover structure of this agro-pastoral system. The upper watershed of the Tergi River with its tributaries in the Central Greater Caucasus is considered to be prone to current and future land-use change affecting the diversity, productivity and integrity of the grassland ecosystems (Magiera et al, 2013;Tephnadze et al, 2014). Consequently, concepts of sustainable, agricultural land use considering site-specific carrying capacity as well as profitability of land use are urgently needed to maintain the valuable cultural landscape and to strengthen the rural development of remote areas.…”

Section: Introductionmentioning

confidence: 99%

Land-Use Change Related to Topography and Societal Drivers in High-Mountains – A Case Study in the Upper Watershed of the Tergi (Kazbegi Region), Greater Caucasus

Theissen

Otte

Waldhardt

2019

European Countryside

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High mountain ecosystems, with strong topographic and climatic gradients, are fragile and particularly sensitive to changes in land use. The abandonment of historic cultural landscapes has often led to changes in the pattern of land cover and thus, to a shift in the functions of high mountain landscapes, like fresh water supply, productivity or erosion control. In order to understand the effects of land-use change on the land-cover pattern at the local and regional scale, we analyzed and classified the mountainous landscape structure in the Kazbegi region in Georgia, located in the Central Greater Caucasus. For 13 settlements, we determined the land cover as present in 1987 and 2015, and quantified the changes over time to detect land-cover development trends for each settlement. Using a cluster analysis, the study area was analyzed regarding to topography (altitude, aspect, slope) and distance to settlements at the regional scale to gain six groups with separating conditions. Furthermore, each settlement was classified according to topography and land-cover change to obtain site-specific, comparative development trends. Our results show that this Caucasian high-mountain landscape is characterized by open grassland (67%) used as pasture and hay meadow, and natural birch forests (7%) in patches in the upper half of the subalpine belt. Within the settlements but also in their surroundings, field vegetables are cultivated in home gardens (1%). Land-cover change during the observation period mainly affected the cultural grassland with hay meadow abandonment. Moreover, shrubbery and forest expanded considerably on abandoned pastures. We further detected a strong relationship to topography that considerably varied between settlements resulting in specific trends in land-use change. Hay-making and arable land cultivation are focused today on sun-exposed and gentle slopes near the settlements. Shrub encroachment and reforestations were localized on farther distances and mostly on north-exposed slopes. Besides providing basic information about the historic and current land-use and land-cover patterns, our results quantify the landscape change during almost 30 years. A spatio-temporal analysis revealed an understanding of how land-use decisions influence the landscape pattern. In the context of societal development, regional socioeconomic processes, like shifts in the agricultural structure and population outmigration, seem to be societal drivers of changes. Our findings reveal linkages and interrelationships between natural, human-induced environmental and socioeconomic processes within high-mountain socio-ecological systems. Moreover, we suggest that sustainable land-use strategies for spatial development on sub-regional level, especially in marginal high-mountain regions, should consider topography and its influence on land-use change.

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Relating canopy reflectance to the vegetation composition of mountainous grasslands in the Greater Caucasus

Cited by 13 publications

References 78 publications

Mapping Plant Functional Groups in Subalpine Grassland of the Greater Caucasus

Mapping Plant Functional Groups in Subalpine Grassland of the Greater Caucasus

Honey Crop Estimation From Space: Detection of Large Flowering Events in Western Australian Forests

Land-Use Change Related to Topography and Societal Drivers in High-Mountains – A Case Study in the Upper Watershed of the Tergi (Kazbegi Region), Greater Caucasus

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