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  • Author or Editor: Z. Botta-Dukát x
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In this paper we present an implementation of the natural capital index (NCI), a highly aggregated policy-relevant biodiversity indicator for Hungary, based on the MÉTA database, a detailed field-based vegetation database with a habitat quality attribute. To this end, we introduce two different weighting schemes for the field-estimated MÉTA values, both rooted in the concept of ecosystem services: a linear “equal steps” (NCI lin ) and an exponential (NCI exp ) weighting scheme. The natural capital index of Hungary and its physical geographical regions are calculated and presented from both aspects. The national NCI lin is 9.9% (indicating an overall 90% loss in the availability of the major supporting ecosystem services), and NCI exp is 3.2% (indicating an even greater degree of loss in terms of the conservation of rare species). The geographical regions of Hungary exhibit considerable spatial variation, which reveals important information on their basic characteristics (e.g. agricultural potential) and land use history. As NCI can be calculated on any spatial scales from local to national, this indicator may become a useful tool for policy development and evaluation purposes, including environmental impact assessments (EIA) and strategic environmental assessments (SEI). However, due to several conceptual limitations (e.g. disregard for rarity, spatial structure and cultural values, questions of recency and repetition) NCI should not be regarded as a self-sufficient universal tool, and strategic decisions should be based on careful consideration of all potentially relevant factors.

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We review the population ecology of Allium ursinum according to its life history, phenology, demography, dispersal, and population dynamics. Spatial distribution is reviewed on two spatial scales. First, on a broad scale over Europe, in relation to the habitat requirement of the species. Second, on a fine scale of individual patches, presenting some results about the local processes of density regulation and patch formation. We conclude that A. ursinum has a distinct, hitherto non-described, strategy for monopolizing space and dominating the forest floor. This Clan-of-Clones strategy has the following attributes. 1) Most of the seeds are dispersed close to the parent. 2) Seedling establishment is facilitated by the surrounding adults. 3) Allocation to vegetative reproduction is relatively small; its main role is to prolong local persistence. 4) The genet is not integrated physiologically, except for a transient connection between parent and offspring. An important consequence of the Clan-of-Clones strategy is that occupied patches can be fine-grained mosaics in terms of genetic composition and age groups.

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We studied the long-term impact of wildfire on the vegetation dynamics of sand grasslands in a forest-steppe vegetation mosaic in Central Hungary (Kiskunság). Long-term permanent quadrat monitoring was carried out from 1997 to 2008. We sampled the forest-steppe mosaic both in burnt and unburnt areas in 100 patches altogether using 1 m × 1 m quadrats. The effect of fire and precipitation on vegetation dynamics was characterized by patch type transitions between years. Patch types were defined by means of Cocktail method. Nine patch types of sand grasslands were altogether identified. The least productive patch types, bare soil and cryptogam dominance, did not occur in the burnt patches, while annual dominated patch type appeared only in burnt patches. The frequencies of patch type changes were significantly higher in burnt patches than in unburnt ones, independently on time after fire. All the eight patch types found in the unburnt patches proved permanent, while in the burnt patches only four of seven were so. The relative frequency of patch type changes did not correlate with precipitation in the vegetation period in the unburnt patches, while positively correlated in the burnt patches. It was concluded that the long-term difference in grassland dynamics between the unburnt and burnt patches, i.e., the excess of the patch type transitions in the burnt grasslands, is due to increased drought sensitivity of the grassland, which is the consequence of the elimination of the woody component of the forest-steppe vegetation.

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Acta Botanica Hungarica
Authors: B. Lhotsky, A. Csecserits, B. Kovács, and Z. Botta-Dukát

Canopy height, leaf area (LA), specific leaf area (SLA) and leaf dry matter content (LDMC) data of 210 species of the Hungarian flora resulting from our field sampling are presented in this data paper.

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Community Ecology
Authors: E. Lellei-Kovács, E. Kovács-Láng, T. Kalapos, Z. Botta-Dukát, S. Barabás, and C. Beier

The influence of simulated climate change on soil respiration was studied in a field experiment on 4 m × 5 m plots in the semiarid temperate Pannonian sand forest-steppe. This ecosystem type has low productivity and soil organic matter content, and covers large areas, yet data on soil carbon fluxes are still limited. Soil respiration rate — measured monthly between April and November from 2003 to 2006 — remained very low (0.09 — 1.53 μmol CO 2 m −2 s −1 ) in accordance with the moderate biological activity and low humus content of the nutrient poor, coarse sandy soil. Specific soil respiration rate (calculated for unit soil organic matter content), however, was relatively high (0.36–7.92 μmol CO 2 g −1 C org h −1 ) suggesting substrate limitation for soil biological activity. During the day, soil respiration rate was significantly lower at dawn than at midday, while seasonally clear temperature limitation in winter and water limitation in summer were detected. Between years, annual precipitation appeared to be important in determining soil carbon efflux intensity. Nocturnal warming increased soil temperature in 1 cm depth at dawn by 1.6°C on the average, and decreased topsoil (0–11 cm) moisture content by 0.45 vol%. Drought treatment decreased soil moisture content by an average of 0.81 vol%. Soil respiration rate tended to decrease by 7–15% and 13–15% in response to heat and drought treatment, respectively, although the changes were not statistically significant. Nocturnal warming usually prevented dew formation, and that probably also influenced soil respiration. Based on these results, we expect a reduction in the volume and rate of organic matter turnover in this ecosystem in response to the anticipated climate change in the region.

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Community Ecology
Authors: G. Ónodi, Gy. Kröel-Dulay, E. Kovács-Láng, P. Ódor, Z. Botta-Dukat, B. Lhotsky, S. Barabás, J. Garadnai, and M. Kertész

Aboveground plant biomass is one of the most important features of ecosystems, and it is widely used in ecosystem research. Non-destructive biomass estimation methods provide an important toolkit, because the destructive harvesting method is in many cases not feasible. However, only few studies have compared the accuracy of these methods in grassland communities to date. We studied the accuracy of three widely used methods for estimation of aboveground biomass: the visual cover estimation method, the point intercept method, and field spectroscopy. We applied them in three independent series of field samplings in semi-arid sand grasslands in Central Hungary. For each sampling method, we applied linear regression to assess the strength of the relationship between biomass proxies and actual aboveground biomass, and used coefficient of determination to evaluate accuracy. We found no evidence that the visual cover estimation, which is generally considered as a subjective method, was less accurate than point intercept method or field spectroscopy in estimating biomass. Based on our three datasets, we found that accuracy was lower for the point intercept method compared to the other two methods, while field spectroscopy and visual cover estimation were similar to each other in the semi-arid sand grassland community. We conclude that visual cover estimation can be as accurate for estimating aboveground biomass as other approaches, thus the choice amongst the methods should be based on additional pros and cons associated with each of the method and related to the specific research objective.

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