Gergő Németh

A Kis-Balaton a 19. század első feléig közel érintetlen táj volt, azonban az 1860-as évektől kezdve a vízrendezések következtében jelentősen átalakult. A Zala folyót gátak közé szorították, ezért megszűnt az összeköttetése a mocsaras területekkel, vagyis a víz közvetlenül a tóba jutott. Ennek következtében a Kis-Balaton már nem tudta ellátni korábbi szűrőfunkcióját, amely a Balaton vízminőségének romlását eredményezte. A tájhasználat megváltozott, a nyílt vízfelszínek és az erdők visszaszorultak, a szántók terjeszkedni kezdtek. Az 1980-as évektől a probléma megoldása érdekében a terület részleges elárasztása mellett döntöttek, amely elősegítette a víztisztítást és az élővilág számára számos kedvező hozadékkal járt.

Over the past few centuries, the loss of wetlands has reached alarming proportions worldwide, and Hungary has been especially affected. Due to population growth and the expansion of industrial production, the demand for arable land increased, so rivers were dammed, the vast majority of our wetlands were drained and their place was taken by agricultural fields. Mohács Island is a typical example of intensive landscape transformation. The area formerly covered by floodplain forests and marshes has become a cultural landscape in which the habitat of natural ecosystems has become quite narrow. Our research examines and evaluates the changes in landscape use that have taken place from the second half of the 19th century to the present day, and provides a comprehensive picture of the transformation of landscape structure. The most important turning point was the beginning of the 20th century, when the island lost its natural character as a result of water control works, and its surface was dominated by fields rather than forests. This was accompanied by a decline in diversity. The landscape became more monotonous and indigenous associations were marginalised. Simultaneously, landscape-ecological relationships weakened, habitats became isolated from each other. One of the main aims of conservation is to restore the links between these areas and, where possible, former habitats. It is not possible to reconstruct the entire study area, but effective results can be achieved through locally feasible projects to enhance biodiversity.

Recently light pollution has been one of the most dynamically increasing form of environmental pollution. Light, if it arrives at the wrong place, time, quantity and quality, is harmful to human health and the physical environment-not to mention that it is a mere waste of energy. The brightness of the sky above Pécs was measured by SQM-L instruments in 2011 and 2019. Maps of the different neighbourhoods with different levels of light pollution have been prepared. In addition, special VIIRS day/night band satellite images were also analysed using QGIS software. Our investigations coincided with the modernization of street lighting in the city. The impact of LED illuminators installed along main roads in Pécs was observed locally.

This paper presents the trends of landscape change in the marshes on the southern shore of Lake Balaton, a wetland profoundly transformed by human activities. The study does not only deal with alterations in the areal proportions of land use classes but also quantitatively analyses landscape pattern, comparing landscape metrics on different dates. Based on the findings, proposals for rehabilitation are made. Through the restoration of wetland habitats, the provision level of ecosystem services can be raised. Landscape change was investigated from 1783 to 2020. For this purpose, archive maps were digitized, CORINE land cover datasets corrected by Sentinel-2 imagery were employed and from the vector data, the proportions of land use classes were calculated. For landscape pattern perimeter, area, neighbourhood and diversity metrics were used, calculated by ArcGIS vLATE plugin. It was pointed out that in land cover, the share of wetlands considerably declined over the centuries but in recent decades somewhat expanded. In the 20th century, grasslands were the predominant land use class, but with the spread of other categories, land use has become more complex. Landscape metrics show an increased fragmentation of natural habitats, a higher number of patches and edge density, leading to higher landscape diversity. Rehabilitation proposals include the establishment of rainwater retention reservoirs, the conversion of arable land which cannot be cultivated profitably to close-to-natural classes (first of all, grasslands) and the plantation of gallery forests of native tree species along canals. In comparison with other regions, similar temporal trends and spatial distributions are observed. For instance, the internationally well-known transformation of the Doñana wetland started later but was more intensive than in Hungary.

Mezőgazdasági hasznosítású dombsági területen vizsgáltuk a földhasználati kategóriák arányainak és a táj mintázatának történeti változásait, valamint ezek következményeit a 18. század második felétől kezdődően. A kutatás során archív térképeket elemeztünk és hasonlítottunk össze. A tanulmányozott terület fragmentáltságának alakulását a hatékony rácsméret index segítségével követtük. A mintaterületen előforduló legjelentősebb tájhasználatbeli változás az erdők visszaszorulása a szántók javára. Ennek számos gyakorlati hátránya van, hiszen a biodiverzitás csökken, az ökológiai kapcsolatrendszer lazul, a kiirtott erdők helyén a felszínen gyorsabban lefolyó vizek növelik a talajerózió és az áradások veszélyét. Az utóbbi évtizedekben azonban a táj használatát és szerkezetét érintő változások környezeti szempontból kedvezőnek ítélhetők.