Spatio-temporal changes in land cover and aquatic macrophytes of the Danube floodplain lake

Abstract

a b s t r a c tThe aquatic vegetation ofČíčov Lake in the Danube floodplain, which is listed in the Ramsar Convention, was investigated to address three main questions: (1) how have landscape composition and the structures of the lake and its buffer zone changed from the mid-20th century;(2) how have species richness and the abundance of the aquatic macrophyte assemblage in this lake ecosystem changed over the last 34 years; and (3) which landscape metrics can best explain these temporal changes for floating-leaved macrophytes? Two methodological approaches, remote sensing and botanical field surveys, were applied. Historical (1949, 1970, 1990) and contemporary (2006) aerial photographs were analysed to determine land cover. Landscape configuration and structure were analysed using eight landscape metrics selected in advance to measure spatio-temporal changes and the fragmentation of the lake ecosystem and its corresponding buffer zone. The species diversity, abundance and distribution of true aquatic macrophytes were surveyed eleven times in five survey stretches between 1973 and 2007.At the landscape level, a decrease in the area covered by floating-leaved macrophytes, as well as an increase in open water surface and fragmentation of the land cover classes in the lake ecosystem, were recorded from 1949 to 2006. Overall, 30 true aquatic macrophytes were found from 1973 to 2007. Species richness did not change considerably, but the abundance of aquatic species fluctuated over the years. Three groups of true aquatic vegetation, based on common structural characteristics, were found in 1973-1983, 1989-2002, and 2004-2007 over the last 34 years. The landscape metrics NP, PD, LPI, and SHDI, which all express patterns of landscape fragmentation mostly indicate temporal changes in floatingleaved macrophytes.

Temporal beta diversity of lake plants is determined by concomitant changes in environmental factors across decades

“…Oťaheľová et al. (2011) found that during a 34‐year time period, aquatic plant species richness did not change much in floodplain lake ecosystems, although the abundance of aquatic plants fluctuated over the years. Therefore, using abundance data would reveal a more detailed picture of temporal ecological change.…”

Artificial Regulation of Water Level and Its Effect on Aquatic Macrophyte Distribution in Taihu Lake

“…Although some authors have found correlations between the variation in aquatic vegetation and water levels in regard to aquatic systems at large temporal scales, most of those studies were based on either limited short-term or discrete long-term data [12] , [13] , [32] , and thus the results are either narrowly applicable or easily confounded by the cumulative effect of other environmental factors with gradual temporal variation, such as trophic status. In this project, we mapped aquatic vegetation distribution between 1989 and 2010 based on remote sensing images with spatial resolutions from 15 to 30 m. Our objective was to determine the effect of managed water level on the distribution and composition of aquatic macrophytes in Taihu Lake.…”

Ecological status assessment of Skalenski Lakes (Bulgaria)

“…M. spicatum is relatively tolerant to pollution, salinity and pH values, and was found to be positively correlated with segmentation of lakes. [ 44 ]…”