Issn 1730-413x
نویسندگان
چکیده
QuickBird satellite images were processed using object-based analysis to map the spatial structure of seagrass in sandy shoal habitat in the southern Baltic Sea. A three-level ecological model of seagrass landscape, composed of meadows, beds and patches/gaps, was implemented in the multi-scale object domain. Image segmentation was performed at different spatial scales. In order to determine representative scales for bed level and patch/gap level objects, histograms of delineated objects were analyzed. Using object-oriented classification methods, two hierarchically nested maps of seagrass spatial structure were created. The map of patches/gaps was created using the nearest neighbor classification method in the feature space defined by the mean value of band 2 and the value of the proposed seagrass index. Overall map accuracy was 83%. The second map, which depicted the cover density of seagrass beds, was created on the basis of hierarchical relationships between objects at two chosen spatial scale levels. Both maps were exported as vector objects to GIS. Vector-based mapping of seagrass landscape structures at two scales simultaneously provides new possibilities for using landscape metrics and time change detection
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Issn 1730-413x
Nutrients, pH, and organic matter were determined in water samples collected from the Raba River above Dobczyce Reservoir (meso-eutrophic), from the Dunajec River above Czorsztyn Reservoir (mesotrophic), and Rożnów Reservoir (eutrophic), and in the bottom sediments of the reservoirs. The river waters were alkaline (pH 7.2–9.2). In the Raba River and Dunajec River, the ranges of nutrients and or...
متن کاملIssn 1730-413x
During investigations of an inundated opencast sulphur mine (an open, deep water habitat with a relatively small littoral area) only five species of breeding water birds were recorded. The density of breeding great crested grebes Podiceps cristatus was relatively high (c. 1.0-1.1 pairs 10 ha of water, and 1.6-1.8 pairs ha of the macrophyte area) although fish density was very low. High water tr...
متن کاملThe fecundity and gonad development cycle of the round goby (Neogobius melanostomus Pallas 1811) from the Gulf of Gdańsk
The round goby (Neogobius melanostomus Pallas 1811) is a non-native species in the Gulf of Gdańsk. The aim of this article is to assess the absolute fecundity and attempt to describe the gonad development cycle of round goby specimens from the Gulf of Gdańsk. The stages of gonad development were classified according to the modified Nikolski (1963) scale for perciformes, which was adapted for th...
متن کاملUncovering the Nature of the X-ray Transient 4u 1730 22: Discovery of X-ray Emission from a Neutron Star in Quiescence with Chandra
The X-ray transient 4U 1730 22 has not been detected in outburst since 1972, when a single 200 day outburst was detected by the Uhuru satellite. This neutron star or black hole X-ray binary is presumably in quiescence now, and here we report on X-ray and optical observations of the 4U 1730 22 field designed to identify the system’s quiescent counterpart. Using the Chandra X-ray Observatory, we ...
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تاریخ انتشار 2009