János Bölöni

A grid-based, satellite-image supported, multi-attributed vegetation mapping method (MÉTA)

In this paper we present the main characteristics of a new, grid-based, landscape-ecology-oriented, satellite-image supported, field vegetation mapping method, called MÉTA (MÉTA stands for Magyarországi Élőhelyek Térképi Adatbázisa: GIS Database of the Hungarian Habitats). The goals of the MÉTA method based vegetation mapping program (MÉTA mapping) include the following: (1) to map the actual (semi-)natural vegetation of Hungary; (2) to evaluate Hungarian (semi-)natural vegetation heritage for conservation purposes; (3) to evaluate the present state of Hungarian landscapes from a vegetation point of view; (4) to collect vegetation and landscape ecological data for the prognosis of future changes of vegetation and the landscape. Spatial resolution, mapped attributes and mapping methods were developed to meet these goals.The MÉTA method uses a hexagon grid with cells of 35 hectares. In the hexagons, habitat types are listed, then the area, naturalness-based habitat quality, spatial pattern in the hexagon, effect of the neighbourhood, connectedness, and threats are recorded for each habitat type. Other attributes are recorded in the hexagons: potential natural vegetation, area occupied by invasive plant species, area of old fields, land use of grasslands, and landscape health status (naturalness and regeneration potential of the landscape in general). One hundred hexagons form a quadrat — mainly for practical, organizational reasons, but also for collecting certain vegetation data at this spatial scale. For standardization of mapping, three different pre-printed data sheets and two different kinds of guides have been composed (Mapping Guide and Habitat Guide) and field trainings were organized. For standardization of estimation of naturalness-based habitat quality and regeneration potential field examples were prepared for each habitat type and each category of these attributes.

Implementation and application of multiple potential natural vegetation models – a case study of Hungary

Questions Multiple potential natural vegetation (MPNV) is a framework for the probabilistic and multilayer representation of potential vegetation in an area. How can an MPNV model be implemented and synthesized for the full range of vegetation types across a large spatial domain such as a country? What additional ecological and practical information can be gained compared to traditional potential natural vegetation (PNV) estimates? Location Hungary. Methods MPNV was estimated by modelling the occurrence probabilities of individual vegetation types using gradient boosting models (GBM). Vegetation data from the Hungarian Actual Habitat Database (META) and information on the abiotic background (climatic data, soil characteristics, hydrology) were used as inputs to the models. To facilitate MPNV interpretation a new technique for model synthesis (re-scaling) enabling comprehensive visual presentation (synthetic maps) was developed which allows for a comparative view of the potential distribution of individual vegetation types. Results The main result of MPNV modelling is a series of raw and re-scaled probability maps of individual vegetation types for Hungary. Raw probabilities best suit within-type analyses, while re-scaled estimations can also be compared across vegetation types. The latter create a synthetic overview of a locations PNV as a ranked list of vegetation types, and make the comparison of actual and potential landscape composition possible. For example, a representation of forest vs grasslands in MPNV revealed a high level of overlap of the potential range of the two formations in Hungary. Conclusion The MPNV approach allows viewing the potential vegetation composition of locations in far more detail than the PNV approach. Re-scaling the probabilities estimated by the models allows easy access to the results by making potential presence of vegetation types with different data structure comparable for queries and synthetic maps. The wide range of applications identified for MPNV (conservation and restoration prioritization, landscape evaluation) suggests that the PNV concept with the extension towards vegetation distributions is useful both for research and application.

Abandonment status and long-term monitoring of strict forest reserves in the Pannonian biogeographical region

Abstract The Pannonian region is situated in the Carpathian basin where forests have been used intensively for centuries. The article shows a map and a tabular overview of the forest reserves featured as forests “left for free development” of the region, and presents the most important stand structural characteristics of beech, mesophytic and thermophilous deciduous forests surveyed recently. The sampling points of six sites were selected to provide preliminary descriptive statistics according to the main types and abandonment status groups (recently managed, long abandoned and old-growth or primary stands) of these forests. In old-growth and primary stands the composition (list and mixture ratio of tree species) and stand structure characteristics [gap class distribution, stem density, distribution of relative crown classes and broad diameter at breast height (at 130 cm) classes, density of thick snags, and the amount of lying dead wood] proved to be similar to other European deciduous natural forests, while the abandoned and recently managed stands indicate that these forests are in a transitional stage towards natural ones.

First signs of old-growth structure and composition of an oak forest after four decades of abandonment

Abstract The lack of natural references of dry-mesic oak forests creates conceptual obstacles for their conservation and close-to-nature management in Central Europe. Single-tree inventory was used to investigate stand characteristics and old-growth attributes of a Quercus petraea (Matt.) Liebl. and Q. cerris L. dominated, 120-year-old stand in a Hungarian forest reserve, abandoned approximately 40 years ago. All individuals were recorded with diameter ≥ 5 cm on the 3 ha study site. Logs, stumps, saplings and seedlings were also surveyed. 582 woody stem/ha belonging to 14 species were measured with single-tree inventory. Basal area values showed the total dominance of oaks in the canopy layer (99%) as a legacy of the long-term human exploitation. In contrast, young individuals of oak species were almost missing, and Acer campestre L. dominated the lower layers, indicating the transitional nature of the stand. Diameter classes showed a marked bimodal distribution. Both the abandonment of the reserve and the precedent severe oak decline contributed to the relatively high amount of dead wood (46 m3/ha). Four decades of abandonment is rather short time interval to generate a diverse forest composition and structure in a mature dry-mesic oak forest. The dense regeneration and shrub layer and the upsurgence of admixing species indicate the shift towards the uneven-aged and compositionally more diverse old-growth oak forest state. Among the structural forest features the dead wood had similar values as old-growth forests. If the recent trend continues, the studied oak forest develops towards a mixed forest with significantly lower ratio of oak species.

Use of long-term data to evaluate loss and endangerment status of Natura 2000 habitats and effects of protected areas

Habitat loss is a key driver of biodiversity loss. However, hardly any long-term time series analyses of habitat loss are available above the local scale for finer-level habitat categories. We analysed, from a long-term perspective, the habitat specificity of habitat-area loss, the change in trends in habitat loss since 1989 (dissolution of the communist state), and the impact of protected areas on habitat loss in Hungary. We studied 20 seminatural habitat types in 5000 randomly selected localities over 7 periods from 1783 to 2013 based on historical maps, archival and recent aerial photos and satellite imagery, botanical descriptions, and field data. We developed a method for estimating habitat types based on information transfer between historical sources (i.e., information from a source was used to interpret or enrich information from another source). Trends in habitat loss over time were habitat specific. We identified 7 types of habitat loss over time regarding functional form: linear, exponential, linear and exponential, delayed, minimum, maximum, and disappearance. Most habitats had continuous loss from period to period. After 1986 the average annual rates of habitat loss increased, but the trend reversed after 2002. Nature conservation measures significantly affected habitat loss; net loss was halted, albeit only inside protected areas. When calculating the degree of endangerment based on short-term data (52 years), we classified only 1 habitat as critically endangered, but based on long-term data (230 years), this increased to 7 (including habitat that no longer existed). Hungary will probably reach the global Convention on Biological Diversity Target 5 but will probably not achieve the EU Biodiversity Strategy target of halting habitat loss by 2020. Long-term trend data were highly useful when we examined recent habitat-loss data in a wider context. Our method could be applied effectively in other countries to augment shorter-term data sets on trends in habitat area.

Strict Forest Reserve Research in the Margin of the Carpathians, the Vár-hegy Case-Study

Sixteen forest reserves are situated in the northern part of Hungary which belongs to the Carpathian region according to EURAC delimitation (Ruffini et al. 2006). These Hungarian forest reserves expand the natural forest remnant/forest reserve net of the Carpathians towards the lower hilly region, representing the deciduous beech and oak forest belts near their lower (xeric) distribution limits. This paper outlines the Hungarian forest reserves belonging to the Carpathian region and the preliminary results of current projects in the Var-hegy Forest Reserve (Bukk Mts., Hungary) as a case study. The alteration of tree species composition was investigated here based on the reconstruction of forest history in the previous 130 years (management period) and analyses of forest stand inventory. In another project CO2 sequestration changes of these forest stands were modeled since the clear-cutting in the 1880th and carbon stored in the forest ecosystem compartments was estimated. Our results show that the forest reserve stands are presently in a transition state from the managed forest towards a more natural mixed forest with several age-classes.