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Improved methods of classification of multispectral aerial photographs: evaluation of floodplain forests in the inundation area of the Danube

100%

Bucha T., Slavik M.

Folia Forestalia Polonica. Series A . Forestry

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2013

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tom 55

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nr 2

The Gabčíkovo hydroelectric power plant has significantly influenced Danube water regime, thus the condition of floodplain forests in the region. Forest condition has been regularly monitored since 1995 using aerial photos. The subject of this study was to improve the procedure of floodplain forest health evaluation based on digital multispectral aerial images. Firstly, the forest mask was created with overall accuracy 89%, and next, tree health was evaluated using defoliation as health indicator. We applied orthogonal transformation of 4 original bands of multispectral imagery into two-dimensional space. Marginal values of digital numbers (DN) of the first component (New Synthetic Channel – NSC1) were defined by fully foliated willow and poplar. The second component (NSC2) was optimised for damage estimation. Calculated DN values of NSC2 represented a perpendicular distance from the line of DN values of the first component. The distance from the line was proportionate to tree damage extent in a given pixel. We generated linear regression model between pair values of NSC2 and defoliation evaluated for 38 trees in the field, respectively, from aerial photos. A decline prediction resulted in r-square equal 0.86. Finally, we used the model to predict defoliation for each picture element (pixel) of the component NSC2.

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Change in metazooplankton abundance in response to flood dynamics and trophic relations in Danubian floodplain lake (Kopacki Rit, Croatia)

67%

Galir A., Palijan G.

Polish Journal of Ecology

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2012

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tom 60

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nr 4

This study investigated relationships of hydrological variability and potential food resources for metazooplankton groups: rotifers, cladocerans, copepods and nauplii. Samples were collected monthly during ice-free season from March until November in 2006. Two sampling stations were chosen, the one located in Lake Sakadaš, as a segment of Kopački Rit floodplain (Croatia), and the other in the River Danube. Due to hydrological conditions we divided our samples into two hydrological groups which corresponded to: 1/ increased water level i.e. disturbed phase and 2/ decreased water level representing a more stable phase. Abundance of metazooplankton was not significantly different between hydrological groups in the River Danube. However, it was significantly different between hydrological groups in Lake Sakadaš (one-way ANOSIM R = 0.688, P = 0.024), where during a decreased water level higher abundance of metazooplankton was recorded. Rotifers were the most abundant metazooplankton group during the whole investigated period at both stations and between both hydrological groups comprising almost 99% of total metazooplankton abundance. Rotifers were significantly positively correlated with the total number of bacteria, as well as with ammonium and total phosphorous concentrations. The metazooplankton community in Lake Sakadaš was negatively influenced by flooding, but not in the River Danube. Compared to the River Danube the investigated floodplain lake showed potential as a storage zone for metazooplankton development during more stable hydrological periods. During that time abundance of rotifers was related to the heterotrophic component of microbial food web. Hence, this investigation adds to the understanding of the metazooplankton dynamics in riverfloodplain systems as well as of their relations with trophic levels under variable hydrological conditions.

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Natural and man-induced hazards along the Danube, between Rast and Gighera settlements, with a special view on the 2006 flood

67%

Licurici M., Boengiu S., Ionus O.

Quaestiones Geographicae

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2011

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tom 30

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nr 1

Ograniczanie wyników

1 Folia Forestalia Polonica. Series A . Forestry

1 Polish Journal of Ecology

1 Quaestiones Geographicae

1 Boengiu S.

1 Bucha T.

1 Galir A.

1 Ionus O.

1 Licurici M.

1 Palijan G.

1 Slavik M.

1 2013

1 2012

1 2011

Improved methods of classification of multispectral aerial photographs: evaluation of floodplain forests in the inundation area of the Danube

Change in metazooplankton abundance in response to flood dynamics and trophic relations in Danubian floodplain lake (Kopacki Rit, Croatia)

Natural and man-induced hazards along the Danube, between Rast and Gighera settlements, with a special view on the 2006 flood