Current high-resolution remote sensing provides the means to accurately map upland swamp boundaries and vegetation communities in eastern Australian coastal woodlands. The aim of this study was to develop baseline methods for upland swamp definition and change detection that can be routinely applied in an operational setting.
Quantification of landscape-based vegetation structural variation and pattern is a significant goal for a variety of ecological, monitoring and biodiversity studies. Vegetation structural metrics, derived from airborne laser scanning (ALS or aerial light detection and ranging*LiDAR) and QuickBird satellite imagery, were used to establish the degree of plot-based vegetation variation at a hillslope scale. Topographic position is an indicator of energy and water availability, and was quantified using DEMbased insolation and topographic wetness, respectively, stratifying areas into hot-warm-cold and wet-moist-dry topographic classes. A range of vegetation metrics*maximum and modal canopy height, crown cover, foliage cover, NDVI and semivariance*were compared among randomly selected plots from each topographic class. NDVI increases with increasing landscape wetness, whereas ALS-derived foliage cover decreases with increasing insolation. Foliage cover is well correlated with crown cover (R 2 00.65), and since foliage cover is readily calculable for whole-of-landscape application, it will provide valuable and complementary information to NDVI. Between-plot heterogeneity increases with increasing wetness and decreasing insolation, indicating that more sampling is required in these locations to capture the full range of landscape-based variability. Pattern analysis in landscape ecology is one of the fundamental requirements of landscape ecology, and the methods described here offer statistically significant, quantifiable and repeatable means to realise that goal at a fine spatial grain.
Patients with symptomatic aneurysms that are not excluded from the cerebral circulation have a poor prognosis. Standard treatment is surgical exploration with direct clipping of the aneurysm. Because of their large size or relationship to the base of the skull, some aneurysms may not be suitable for direct surgical clipping and may require alternative treatment modalities. A prospective clinical and radiological study of seven patients treated with the endovascular placement of platinum-Dacron microcoils to exclude the aneurysm from the cerebral circulation is reported. The seven patients ranged in age from 37 to 63 years; four were women. At completion of the endovascular procedure, total occlusion of the aneurysm with preservation of the parent artery had been achieved in four patients and 90% occlusion of the aneurysm in two. In the seventh patient, occlusion of the internal carotid artery resulted in the patient's death. At the 6-month follow-up review, both patients with an aneurysm less than 20 mm in size had persistent aneurysm thrombosis; however, the two patients with giant aneurysms had partial recanalization. Both required repeat thrombosis of their aneurysm with the placement of additional microcoils, one at 6 weeks and one at 6 months. These two patients have persistent aneurysm thrombosis at 12 months following their second procedure. The patient mortality rate for this study was 14%, while the procedure mortality/morbidity rate was 9%. It is concluded that thrombotic aneurysm therapy of difficult aneurysms is a safe procedure and will have a place in the treatment of selected aneurysms.
Airborne laser scanning (ALS) has the potential to capture a range vegetation structural metrics, but most studies have focussed on conifer or mixed conifer-deciduous cool-temperate or boreal forests. This study focuses on a warm-temperate eucalypt forest, where two epochs of ALS data, captured approximately 2 years apart, were compared with plot and transect field data collected after the second ALS epoch. Linear regression was used to compare metrics from field and ALS data, and Student's t-tests were used to compare metrics from the two ALS epochs. Statistically significant relationships were found for tree height (R 2 = 0.915; SE = 2.08 m; P < 0.01) and canopy cover (R 2 = 0.508; SE = 16.4%; P < 0.01). Foliage projective cover was also significantly correlated (R 2 = 0.916; SE = 4.5%; P < 0.01) at a 10-m stratification, but not at the typically computed 2-m stratification, because of the presence of a tall scrubby understorey. Statistically significant values were also obtained from ALS data captured 2 years earlier, although correlation was not as strong, most likely because of the greater interval between fieldwork and ALS capture. Importantly, significant agreement was found for all metrics when the two ALS epochs were compared, suggesting that the metrics are robust.
We aimed to elucidate nesting requirements and nest success of the threatened little eagle (Hieraaetus morphnoides). Nest sites (n=12 active and 2–5 recent historical nests) near Armidale, New South Wales, were measured in 2017 at three scales: the nest tree, the nest woodland (≤25m from the nest tree), and (using GIS) the landscape scale (within 200-m and 2-km radii of the nest). The eagles typically nested ≥14m above ground in the canopy of emergent (>20m tall) living eucalypts in sheltered positions (midslope, with a north-easterly to southerly aspect), in woodland patches >5ha (mean 76ha), <200m (mean 78m) from the woodland edge, though ≥11m (mean 190m) from an agricultural edge, ≥38m (mean 485m) from the nearest rural dwelling, >1km from suburbia, and farther from sealed roads (mean 832m) than gravel roads (mean 490m) than minor tracks (mean 291m). Breeding productivity in 2017–18 (n=15 and 18 territories, respectively) was 0.91 young fledged per attempt (clutch laid) and 0.67 young fledged per occupied territory per year. Nest sites were used annually for at least 3–7 years. Nest abandonments or site shifts were associated with human disturbance (e.g. clearing, earthmoving, subdivision and construction in or beside the nest patch), death of the nest tree or nest stand (‘eucalypt dieback’ or rural tree decline), pindone baiting for rabbits (Oryctolagus cuniculus), and displacement by wedge-tailed eagles (Aquila audax) and ravens (Corvus sp.). As most little eagle nests were located on private land, we recommend, inter alia, greater protection of breeding habitat, nest sites and foraging habitat, woodland regeneration (especially riparian), and a buffer around established nests of ≥1km from major developments such as urbanisation.
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