TY  - JOUR
A1  - Ullmann, Tobias
A1  - Banks, Sarah N.
A1  - Schmitt, Andreas
A1  - Jagdhuber, Thomas
T1  - Scattering characteristics of X-, C- and L-Band PolSAR data examined for the tundra environment of the Tuktoyaktuk Peninsula, Canada
JF  - Applied Sciences
N2  - In this study, polarimetric Synthetic Aperture Radar (PolSAR) data at X-, C- and L-Bands, acquired by the satellites: TerraSAR-X (2011), Radarsat-2 (2011), ALOS (2010) and ALOS-2 (2016), were used to characterize the tundra land cover of a test site located close to the town of Tuktoyaktuk, NWT, Canada. Using available in situ ground data collected in 2010 and 2012, we investigate PolSAR scattering characteristics of common tundra land cover classes at X-, C- and L-Bands. Several decomposition features of quad-, co-, and cross-polarized data were compared, the correlation between them was investigated, and the class separability offered by their different feature spaces was analyzed. Certain PolSAR features at each wavelength were sensitive to the land cover and exhibited distinct scattering characteristics. Use of shorter wavelength imagery (X and C) was beneficial for the characterization of wetland and tundra vegetation, while L-Band data highlighted differences of the bare ground classes better. The Kennaugh Matrix decomposition applied in this study provided a unified framework to store, process, and analyze all data consistently, and the matrix offered a favorable feature space for class separation. Of all elements of the quad-polarized Kennaugh Matrix, the intensity based elements K0, K1, K2, K3 and K4 were found to be most valuable for class discrimination. These elements contributed to better class separation as indicated by an increase of the separability metrics squared Jefferys Matusita Distance and Transformed Divergence. The increase in separability was up to 57% for Radarsat-2 and up to 18% for ALOS-2 data.
KW  - decomposition
KW  - arctic
KW  - PolSAR
KW  - dual polarimetry
KW  - quad polarimetry
KW  - TerraSAR-X
KW  - Radarsat-2
KW  - ALOS
KW  - ALOS-2
KW  - tundra
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158362
VL  - 7
IS  - 6
ER  - 
TY  - JOUR
A1  - Englmeier, Jana
A1  - von Hoermann, Christian
A1  - Rieker, Daniel
A1  - Benbow, Marc Eric
A1  - Benjamin, Caryl
A1  - Fricke, Ute
A1  - Ganuza, Cristina
A1  - Haensel, Maria
A1  - Lackner, Tomáš
A1  - Mitesser, Oliver
A1  - Redlich, Sarah
A1  - Riebl, Rebekka
A1  - Rojas-Botero, Sandra
A1  - Rummler, Thomas
A1  - Salamon, Jörg-Alfred
A1  - Sommer, David
A1  - Steffan-Dewenter, Ingolf
A1  - Tobisch, Cynthia
A1  - Uhler, Johannes
A1  - Uphus, Lars
A1  - Zhang, Jie
A1  - Müller, Jörg
T1  - Dung-visiting beetle diversity is mainly affected by land use, while community specialization is driven by climate
JF  - Ecology and Evolution
N2  - Dung beetles are important actors in the self-regulation of ecosystems by driving nutrient cycling, bioturbation, and pest suppression. Urbanization and the sprawl of agricultural areas, however, destroy natural habitats and may threaten dung beetle diversity. In addition, climate change may cause shifts in geographical distribution and community composition. We used a space-for-time approach to test the effects of land use and climate on α-diversity, local community specialization (H\(_2\)′) on dung resources, and γ-diversity of dung-visiting beetles. For this, we used pitfall traps baited with four different dung types at 115 study sites, distributed over a spatial extent of 300 km × 300 km and 1000 m in elevation. Study sites were established in four local land-use types: forests, grasslands, arable sites, and settlements, embedded in near-natural, agricultural, or urban landscapes. Our results show that abundance and species density of dung-visiting beetles were negatively affected by agricultural land use at both spatial scales, whereas γ-diversity at the local scale was negatively affected by settlements and on a landscape scale equally by agricultural and urban land use. Increasing precipitation diminished dung-visiting beetle abundance, and higher temperatures reduced community specialization on dung types and γ-diversity. These results indicate that intensive land use and high temperatures may cause a loss in dung-visiting beetle diversity and alter community networks. A decrease in dung-visiting beetle diversity may disturb decomposition processes at both local and landscape scales and alter ecosystem functioning, which may lead to drastic ecological and economic damage.
KW  - coleoptera
KW  - coprophagous beetles
KW  - decomposition
KW  - global change
KW  - hill numbers
KW  - network analysis
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312846
SN  - 2045-7758
VL  - 12
IS  - 10
ER  -