Imre Berki

The incorporation of extreme drought events improves models for beech persistence at its distribution limit

ContextProjections of species distribution models under future climate are usually based on long-term averages. However, singular extreme drought events presumably contribute to the shaping of distribution limits at the retreating low-elevation xeric limits.MethodsThe objectives of this study were to set up a distribution model based on extreme drought events (EDM), which uses sanitary logging information as a proxy of vitality response of beech, and compare it with the results of classical species distribution models (SDMs).ResultsPredictions of the EDM for 2025 were in agreement with those of the SDM, but EDM predicted a more serious decline in all regions of Hungary towards the end of the century.ConclusionThese results suggest that the predicted increase in frequency and severity of drought events may further limit the distribution of beech in the future.

Long-term effects of climate change on carbon storage and tree species composition in a dry deciduous forest

Abstract Forest vegetation and soils have been suggested as potentially important sinks for carbon (C) with appropriate management and thus are implicated as effective tools in stabilizing climate even with increasing anthropogenic release of CO2. Drought, however, which is often predicted to increase in models of future climate change, may limit net primary productio (NPP) of dry forest types, with unknown effects on soil C storage. We studied C dynamics of a deciduous temperate forest of Hungary that has been subject to significant decreases in precipitation and increases in temperature in recent decades. We resampled plots that were established in 1972 and repeated the full C inventory by analyzing more than 4 decades of data on the number of living trees, biomass of trees and shrubs, and soil C content. Our analyses show that the decline in number and biomass of oaks started around the end of the 1970s with a 71% reduction in the number of sessile oak stems by 2014. Projected growth in this forest, based on the yield tables data for Hungary, was 4.6 kg C/m2. Although new species emerged, this new growth and small increases in oak biomass resulted in only 1.9 kg C/m2 increase over 41 years. The death of oaks increased inputs of coarse woody debris to the surface of the soil, much of which is still identifiable, and caused an increase of 15.5%, or 2.6 kg C/m2, in the top 1 m of soil. Stability of this fresh organic matter input to surface soil is unknown, but is likely to be low based on the results of a colocated woody litter decomposition study. The effects of a warmer and drier climate on the C balance of forests in this region will be felt for decades to come as woody litter inputs decay, and forest growth remains impeded. &NA; The distribution of dry, extreme dry, and wet years from 1953 to 2014 (Bases: 1950–1980 average precipitation). The shaded area represents the time frame of the oak decline. Dry conditions in forest, forest stand composition and diversity change, net primary production, and oak decline. Figure. No caption available.

Modelling the Potential Distribution of Three Climate Zonal Tree Species for Present and Future Climate in Hungary

Abstract The potential distribution and composition rate of beech, sessile oak and Turkey oak were investigated for present and future climates (2036-2065 and 2071-2100) in Hungary. Membership functions were defined using the current composition rate (percentage of cover in forest compartments) of the tree species and the long-term climate expressed by the Ellenberg quotient to model the present and future tree species distribution and composition rate. The simulation results using the regional climate model REMO showed significant decline of beech and sessile oak in Hungary during the 21st century. By the middle of the century only about 35% of the present beech and 75% of the sessile oak stands will remain above their current potential distribution limit. By the end of the century beech forests may almost disappear from Hungary and sessile oak will also be found only along the Southwest border and in higher mountain regions. On the contrary the present occurrences of Turkey oak will be almost entirely preserved during the century however its distribution area will shift to the current sessile oak habitats. Kivonat Három klímazonális fafaj hazai potenciális elterjedésének modellezése jelenlegi és jövőbeni klímában. A bükk, a kocsánytalan tölgy és a csertölgy potenciális elterjedését és elegyarányát vizsgáltuk Magyarországon a jelenlegi és a jövőben (2036-2065 és 2071-2100) várható klimatikus körülmények között. A vizsgált fafajok jelenlegi elegyarányának (az erdőrészletben elfoglalt terület aránya, %) és a klímának (az Ellenberg index-el kifejezve) az összefüggését használtuk a fafajok elterjedésének modellezéséhez. A REMO regionális klímamodellel történt szimuláció a bükk és a kocsánytalan tölgy elterjedési területének és elegyarányának jelentős csökkenését mutatta a 21. század folyamán. A század közepére a jelenlegi bükk állományok 35%-a, a kocsánytalan tölgy állományok 75%-a maradna a jelenlegi alsó elterjedési határuk felett. A század végére a bükk szinte teljesen eltűnhet Magyarország területéről és a kocsánytalan tölgy is a magasabb hegyvidékekre és a délnyugati határ menti területre húzódhat vissza. Ellenben a csertölgy jelenlegi állományait várhatóan nem érinti számottevően a klímaváltozás, viszont az elterjedési területe a jelenlegi kocsánytalan tölgyes állományok helyét foglalhatja el.

Influence of human impacts on trace metal accumulation in soils of two Hungarian cities

Despite the advanced activity of urban soil research, comparison of available trace metal contents in the soil of settlements has not yet been well investigated. First aim of research was the comparison of human impacts on urban soils in two Hungarian cities with different structure and development. To detect the sources of contamination, Szombathely and Sopron cities were separated into urban, suburban and peri-urban areas. Altogether 192 topsoil samples were collected at 0-20 cm in order to measure the physicochemical properties of the soil. Instead of total element contents, plant-available trace metal concentrations - Cd, Co, Cu, Ni, Pb, Zn - were determined using ICP-OES method. Due to different geological conditions, urban soils of the investigated settlements had similar properties in the case of pH, CaCO3 and texture. In the case of plant available trace metals, limit excesses were found in urban and peri-urban areas mostly, but high values were recorded in the suburb. The amount of Cdavailable, Coavailable and Niavailable were negligible. Downtown area was the most contaminated in both cities, but extremes appeared in suburban areas. In Szombathely, Cuavailable values were <40 mg Cu/kg, but extremely high Cuavailable results were found in the peri-urban viticulture areas of Sopron (>90 mg Cu/kg). The samples taken alongside busy roads near the city centre were Pbavailable-contaminated due to traffic. The Pbavailable concentration decreased slightly towards the suburban areas of the cities. The Znavailable level exceeded 40 mg Zn/kg in soils taken from the watercourses of Szombathely. The highest trace metal pollution levels were recorded in soils of public parks of Sopron. Urban soils of Szombathely were more homogenized than urban soils of Sopron. Based on statistical analyses and comparison of the relations of urban, suburban, and peri-urban areas of Sopron to Szombathely, Szombathelys urban soils show more homogeneity.

Erdőtársulások és fafajaik átrendeződési lehetőségei a változó klímában

Kutatasunk sokretű megkozelitest tukroz. Honos fafajaink becsult reakcioi alapjan elemeztuk őshonos fafaju erdőtarsulasaink varhato atrendeződeset. Az elmeleti becsleseket osszedolgoztuk az ujulatra es mortalitasra vonatkozo terepi vizsgalatok eredmenyeivel. Potencialis, invaziobiologiai szempontbol alacsony kockazatu cserefafajokat kerestunk a varhatoan visszaszorulo fafajaink esetleges helyettesitesere. A honos es invazios fafafajok eseteben orszagos adatokon nyugvo, cserefafajok eseteben europai leptekű modellezessel is becsultuk a fajok potencialis es prognosztikus elterjedeset. Potencialis termeszetes erdőtarsulas (PTE) adatbazist epitettunk fel az orszag erdőteruleteire az Orszagos Erdőallomany Adattar alapjan, a jelenre es jovőre vonatkozoan egyarant. Eredmenyeink alapjan az erdő- es erdőssztyep-tarsulasok eseteben egyarant a magas osszeteteli (elegyesseg) es szerkezeti diverzitas (gyepekkel, cserjesekkel mozaikolo allomanyok) jelenthet nagyobb alkalmazkodokepesseget. A kivalasztott tajidegen fafajok alkalmazasara csak az uj korulmenyek kozott is vitalis, őshonos taxonok es az altaluk alkotott (akar ujszerű) tarsulasok altal nyujtott lehetősegek kimeruleset kovetően kerulhet sor.