sparse stands mixed with stretches of open water. In addition to reed, inland
marshes (habitat code: 1530* – the star indicates a priority habitat) and calcareous
fens (habitat codes: 7210 & 7230*) can be found in this region. In contrast to the
larger patches of reed, these habitats are considered to be of European importance
in terms of the EC Habitats Directive.
7.3.2 Data and Methods
For this case study two RapidEye images from 2009 (April and August, Level 3A),
a Digital Elevation Model (DEM) to detect small altitude differences, and CORINE
Land Cover data were used.
Within the European Union inland marshes are found solely in the region of
Lake Neusiedl. They are greatly disturbed by increased nutrition input, changes in
hydrology, regrowth of atypical plant types, and a decrease of land-use or degradation through intensive land-use. Some of these disturbances can be related to
climate-induced impacts (e.g. change in moisture conditions). The Environmental
Agency Austria uses an indicator-based approach to evaluate the quality of these
habitats. The indicators employed are area, species composition, hydrology, completeness of typical habitat structures, and presence of disturbance indicator plant
species. Here, a similar approach is used to develop potential habitat maps to
support the monitoring process and consequently to detect areas not known to be
covered by inland marshes. Because most of these indicators cannot be derived
from satellite data, moisture and biomass were used for this investigation.
Moisture can be measured with the Normalised Difference Water Index (NDWI –
Eq. 7.1) adapted for multi-spectral sensors (Gao 1996). This index allows the
detection of water bodies and wet surfaces by utilising the spectral reflectance of
the visible green wavelength and the near infrared (NIR). The requirements of inland
marshes regarding water availability vary significantly. The amplitude ranges from
temporary very dry periods (for alkali steppe) to periodic flooding (for salt steppes or
salt marshes). Therefore, the NDWI is used to detect areas with periodically changing
moisture conditions and permanently flooded or dry areas.
NDWI ¼ Green À NIR
ð
Þ = Green þ NIR
ð
Þ
ð 7:1Þ
Biomass can be approximated with the Normalised Difference Vegetation Index
(NDVI – Eq. 7.2: Tucker 1979). This index is the common vegetation index for the
detection of active biomass in remote sensing applications. In this study, the NDVI
is used for detecting species which indicate a disturbance of inland marshes.
Especially relevant here is reed, which has considerably high biomass production
and replaces the common vegetation composition of inland marshes.
NDVI ¼ Red À NIR
ð
Þ = Red þ NIR
ð
Þ
ð 7:2Þ
7 Remote Sensing-Based Monitoring of Potential Climate-Induced Impacts on Habitats
101
marshes (habitat code: 1530* – the star indicates a priority habitat) and calcareous
fens (habitat codes: 7210 & 7230*) can be found in this region. In contrast to the
larger patches of reed, these habitats are considered to be of European importance
in terms of the EC Habitats Directive.
7.3.2 Data and Methods
For this case study two RapidEye images from 2009 (April and August, Level 3A),
a Digital Elevation Model (DEM) to detect small altitude differences, and CORINE
Land Cover data were used.
Within the European Union inland marshes are found solely in the region of
Lake Neusiedl. They are greatly disturbed by increased nutrition input, changes in
hydrology, regrowth of atypical plant types, and a decrease of land-use or degradation through intensive land-use. Some of these disturbances can be related to
climate-induced impacts (e.g. change in moisture conditions). The Environmental
Agency Austria uses an indicator-based approach to evaluate the quality of these
habitats. The indicators employed are area, species composition, hydrology, completeness of typical habitat structures, and presence of disturbance indicator plant
species. Here, a similar approach is used to develop potential habitat maps to
support the monitoring process and consequently to detect areas not known to be
covered by inland marshes. Because most of these indicators cannot be derived
from satellite data, moisture and biomass were used for this investigation.
Moisture can be measured with the Normalised Difference Water Index (NDWI –
Eq. 7.1) adapted for multi-spectral sensors (Gao 1996). This index allows the
detection of water bodies and wet surfaces by utilising the spectral reflectance of
the visible green wavelength and the near infrared (NIR). The requirements of inland
marshes regarding water availability vary significantly. The amplitude ranges from
temporary very dry periods (for alkali steppe) to periodic flooding (for salt steppes or
salt marshes). Therefore, the NDWI is used to detect areas with periodically changing
moisture conditions and permanently flooded or dry areas.
NDWI ¼ Green À NIR
ð
Þ = Green þ NIR
ð
Þ
ð 7:1Þ
Biomass can be approximated with the Normalised Difference Vegetation Index
(NDVI – Eq. 7.2: Tucker 1979). This index is the common vegetation index for the
detection of active biomass in remote sensing applications. In this study, the NDVI
is used for detecting species which indicate a disturbance of inland marshes.
Especially relevant here is reed, which has considerably high biomass production
and replaces the common vegetation composition of inland marshes.
NDVI ¼ Red À NIR
ð
Þ = Red þ NIR
ð
Þ
ð 7:2Þ
7 Remote Sensing-Based Monitoring of Potential Climate-Induced Impacts on Habitats
101