Land use changes and associated environmental impacts on the Mediterranean shallow Lake Stymfalia, Greece

Abstract

Land cover and land use changes affect ecological landscape functions and processes. Land use changes mainly caused by human activities, is a common reason for wetlands degradation worldwide. Lake Stymfalia, located at Peloponnese, southern Greece, is an ancient wetland with a great ecological value. Lake Stymfalia has been severely degraded and transformed during the past 60 years due to agricultural activities in the surrounding areas and watercourses alterations. In this context, we investigated the land cover/ use changes and the role of the reed beds in the terrestrialization process of this shallow wetland. This particular effort utilized remotely sensed data and Geographical Information Systems (GIS) techniques to estimate land use alterations for the period 1945-1996. Patch related landscape indices were generated to analyze impacts on landscape features. Spatial and thematic information concerning the surface area and the major land cover types of the lake for years 1945, 1960, 1972, 1987, 1992, and 1996 was obtained from aerial photographs and land surveys of the area, and was stored in the GIS database. The 1996 map was ground verified, corrected and updated to 2004 conditions. From the spatio-temporal analysis of the stored data, a permanent decrease of the open water surface has been observed between the years 1945 and 1996. The results indicated that the reed beds expanded dramatically, increasing by 89.3%, and is the predominant aquatic vegetation of the whole wetland. Open water areas and wet meadows decreased by 53.7 and 96.5% respectively. Landscape analyses and, in particular, the use of selected landscape metrics, proved useful for detecting and quantitatively characterising dynamic ecological processes. As land cover/use analysis of the wetland has shown much serious environmental degradation, conservation measures should be undertaken urgently.

The Spatial and Temporal Variability of Limnological Properties of Bovilla Reservoir (Albania)

“…It is well known that changes in land cover and land use affect ecological landscape functions and processes, which mean the erosion phenomena, are very strong; also the capacity of water retention of the eroded land is very scarce (Papastergiadou et al 2007;Wissman 2006).…”

Implications of Human Activities, Land Use Changes and Climate Variability in Mediterranean Lakes of Greece

“…Such effects are likely to lower water tables and affect water supply, especially in areas where water abstraction will be intensified in order to meet the growing demand for water [8]. Other examples from Greece showed that historical land cover/use changes of lakes and wetlands revealed a significant shrinkage of water surface and its replacement with other types of land cover, mainly cultivations [9][10][11]. Consequently, these land use changes combined with climate induced hydrologic alterations are expected to have a drastic effect on the ecology of freshwater lakes, including changes of the biotic communities, eutrophication enhancement, increase of turbidity and a shift to brackish or even saline conditions [12][13][14].…”

Beyond enhancement of macrophyte litter decomposition in sediments from a terrestrializated shallow lake through bioanode employment

“…Then, the settlement of macrophyte litter increases carbon storage, and also is responsible for increasing the sediment layer and accelerating lake terrestrialization [6,7]. Over the past decades, the terrestrialization of aquatic environments due to the deposition of macrophyte-related organic matters has attracted considerable attention [8,9]. Furthermore, accumulated organic matter also causes the depletion of oxygen and accelerates the production of greenhouse gases such as methane.…”