A Review of Wetland Remote Sensing <s> Wildfires and Other Disturbances <s> Abstract A mosaic of JERS-1 L-band synthetic aperture radar (SAR) images was used to investigate the influence of tectonic faults on wetland distributions in ∼200,000 km 2 of central Amazon lowland (0–4° Lat. S, 60–64° Long. W). The geographic distribution of flooded wetland was clearly evident on the mosaic due to the unique characteristics of L-band radar. Two distinct linear boundaries were encountered limiting the northern distribution of wetlands, one north of the Negro river main channel and west of the Branco river, oriented WNW–ESE, and one south of the Negro main channel and east of the Branco, oriented NW–SE. The orientations and positions of these boundaries were consistent with the prevailing tectonic fracture pattern in the region. Geophysical, pedological and geomorphological data supported the hypothesis that these boundaries are tectonically controlled. The ecological, economic and biogeochemical implications of the observed wetland distribution were considered. The distributions of wetland-dependent biota were expected to be severely limited north of the Negro main channel. Fish production, wetland timber yields and methane emissions were also predicted to be exceptionally low in this region. <s> BIB001 </s> A Review of Wetland Remote Sensing <s> Wildfires and Other Disturbances <s> Many of today’s agricultural landscapes once held vast amounts of wetland habitat for waterbirds and other wildlife. Successful restoration of these landscapes relies on access to accurate maps of the wetlands that remain. We used C-band (5.6-cm-wavelength), HH-polarized radar remote sensing (RADARSAT) at a 38° incidence angle (8-m resolution) to map the distribution of winter shorebird (Charadriiformes) habitat on agricultural lands in the Willamette Valley of western Oregon. We acquired imagery on three dates (10 December 1999, 27 January 2000, and 15 March 2000) and simultaneously collected ground reference data to classify radar signatures and evaluate map accuracy of four habitat classes: (1) wet with ≤ 50% vegetation (considered optimal shorebird habitat), (2) wet with > 50% vegetation, (3) dry with ≤ 50% vegetation, and (4) dry with > 50% vegetation. Overall accuracy varied from 45 to 60% among the three images, but the accuracy of focal class 1 was greater, ranging from 72 to 80%. Class 4 coverage was stable and dominated maps (40% of mapped study area) for all three dates, while coverage of class 3 decreased slightly throughout the study period. Among wet classes, class 1 was most abundant (about 30% coverage) in December and January, decreasing in March to approximately 15%. Conversely, class 2 increased dramatically from January to March, likely due to transition from class 1 as vegetation grew. This approach was successful in detecting optimal habitat for shorebirds on agricultural lands. For modest classification schemes, radar remote sensing is a valuable option for wetland mapping in areas where cloud cover is persistent. <s> BIB002 </s> A Review of Wetland Remote Sensing <s> Wildfires and Other Disturbances <s> Wildfires occur annually in UK moorland environments, especially in drought years. They can be severely damaging to the ecosystem when they burn deep into the peat, killing ground-nesting birds and releasing CO2 into the atmosphere. Synthetic aperture radar SAR was evaluated for detecting the 18 April 2003 Bleaklow wildfire scar 7.4 km2. SAR’s ability to penetrate cloud is advantageous in this inherently overcast area. SAR can provide fire scar boundary information which is otherwise labour intensive to collect in the field using a global positioning system GPS. This article evaluates the potential of SAR intensity and InSAR coherence to detect a large peat moorland wildfire scar in the Peak District of northern England. A time-series of pre-fire and post-fire ERS-2 and advanced synthetic aperture radar ASAR Single Look Complex SLC data were pre-processed using SARScape 4.2 to produce georeferenced greyscale images. SAR intensity and InSAR coherence values were analysed against Coordinate Information on the Environment CORINE land‐cover classes and precipitation data. SAR intensity detected burnt peat well after a precipitation event and for previous fire events within the CORINE peat bog class. For the 18 April 2003 fire event, intensity increased to 0.84 dB post-fire inside the fire scar for the peat bog class. InSAR coherence peaked post-fire for moors and heathland and natural grassland classes inside the fire scar, but peat bog exposed from previous fires was less responsive. Overall, SAR was found to be effective for detecting the Bleaklow moorland wildfire scar and monitoring wildfire scar persistence in a degraded peat landscape up to 71 days later. Heavy precipitation amplified the SAR fire scar signal, with precipitation after wildfires being typical in UK moorlands. Further work is required to disentangle the effects of fire size, topography, and less generalized land‐cover classes on SAR intensity and InSAR coherence for detecting fire scars in degraded peat moorlands. <s> BIB003
As a natural disturbance, wildfires usually occur in moorland and sometimes deep in peat. Peatland fires release CO 2 and CO into the atmosphere and polluted water source. It is essential to understand peatland fire information, such as location, burned area, and last occurrence, to protect the nearby environment. Millin-Chalabi et al. BIB003 proved that SAR can detect fire scar boundaries accurately after a precipitation event and can also be used to monitor peatland fire persistence. Radar data have also been used in other research fields. Taft et al. BIB002 found that RADARSAT can be effectively used to identify the habitat of shorebirds in agricultural land. Forsberg et al. BIB001 used JERS-1 L-band SAR images to explore how tectonic faults affect the distribution of wetland.