Szilárd Czóbel

Short-term effects of extensive fertilization on community composition and carbon uptake in a Pannonian loess grassland.

Among the most extended ecosystems of the temperate zone, the seminatural, dry grasslands constitute a substantial proportion in the Carpathian Basin. The aim of our present study was to investigate the short-term effect of extensive fertilization on the species composition and CO2 exchange of loess grassland at community level. The in situ investigation of the latter parameter have not been yet carried out in Pannonian loess grasslands. Most of the parameters studied showed a considerable interannual variation both in the fertilized and in the control stands. As a result of the treatment, the average species number of the fertilized stand decreased by 22%, which was more significant in the autumn (26%) than in the spring. Diversity values, including Shannon index and species richness, increased by nearly 1.5 times in the year with adequate rainfall compared with the initial values. In general, species richness and the ratio of dicots decreased, while the ratio of therophytes, alien competitors, and C4 plants increased with the addition of fertilizers. Significant carbon sequestration potential was only detected during wet periods in the fertilized grass. The rate of CO2 uptake was found to be nearly five times higher in the fertilized stand and nearly three times higher in the control stand during the wet year compared with the previous, extremely dry year. The CO2 uptake potential of the fertilized grassland exceeded that of the control stand by 12% in the year with high rainfall, while the rate of CO2 exchange dropped by 50% in the dry year in the fertilized stand. Our study reinforced the idea that the decline in species richness was not necessarily followed by the reduction of stand level carbon uptake in a short period due to an insignificant change in ecophysiological functional groups.

Long-term scale changes of land use in peasant farming of the Tardona Hills

For centuries, small-scale and family-based peasant farming was the traditional way of life in the Tardona Hills. Use of traditional methods this sustainable farming focused on food production, including plant cultivation and animal husbandry. Records show that farming has been practiced for 800 years in the research area. Since the first Military Survey Map the ratio of cultivated and uncultivated lands parallel with the changes in land use and land cover can be spatially detected. In the mid 19th century records of land use types appeared and became more frequent. The mentioned documents (maps and records) representing different periods well complement each other and enable us to follow centuries-long historical land use and land cover changes. This paper shows the characteristic land use types of peasant farms and their distribution on a selected area of the Tardona Hills from 1784 to 1984. Thereby landscape-scale changes can be detected in the within the mentioned period. These historical records are essential to interpret the data of the recent vegetation.

Instrumental measurement of health status of old natural sessile oak stands

In Hungary increasing emphasis is put on the research regarding the naturalness of forests, because the so-called biosphere crisis – the global level degradation of our biotic environment – seriously aff ects the forest communities. Th is process can most spectacularly manifest itself in the decrease of forest size. Th e health status of forest stands is usually measured by visual measurements, but it is hard to eliminate subjective errors. Because of these, we carried out instrumental measurement with a 3D Acoustic Tomograph in the Kőszeg Mountains, the Börzsöny Mountains and in the Zemplén Mountains. Th e monitoring of health status was made in sessile oak stands which were older than 100 years in 2015. We found the best health status in the stands of the Kőszeg Mts. Th e maximum level of decay was found in the higher layers in relation to ground level because of the frost damage destroying the stands of the Börzsöny Mts. On the other hand, we experienced the highest decay in the lower levels of trunks regarding stands of the Zemplén Mts; this level of deterioration was continuously reduced towards the higher levels. Th e two diff erent trends are attributable to the site conditions and the origin of the stands.