Róbert Gallé

Properties of shrubforest edges: a case study from South Hungary

Knowledge on edge properties is important from a conservation perspective. Our study was carried out in the ancient vegetation mosaic of the Villány Mts, South-Hungary. Sampling was conducted along eight transects, each running from a rock sward through a shrubforest patch into another rock sward. Unlike most studies, we identified edge position objectively, using a moving split-window analysis. Five habitat types along each transect were distinguished: north-facing rock sward interior, north-facing edge, shrubforest interior, south-facing edge, and south-facing rock sward interior. In the forty 2 m2 plots, a total of 157 species were found. Species richness and Shannon-diversity of the edges was higher than those of the shrubforest interiors, but not significantly different from the rock swards. Cover did not differ significantly among habitat types. We found only a few edge-related species. No differences between differently-oriented edges were revealed. Species composition of the edges was influenced mostly by the rock sward matrix. We hypothesize that ecological conditions of the edges resemble those of the rock sward interiors. Thus, sward species can penetrate into shrubforest edges, entailing a similar composition of edges and rock swards, resulting in similar diversities. Edges might be viewed as refugia for valuable plants of rock swards.

The impact of hedge-forest connectivity and microhabitat conditions on spider and carabid beetle assemblages in agricultural landscapes

Agricultural intensification in terms of decreasing landscape complexity and connectivity has negatively affected biodiversity. Linear landscape elements composed of woody vegetation like hedges may counteract this negative trend by providing habitats and enhancing habitat connectivity for different organisms. Here, we tested the impacts of habitat type (forest edges vs. hedges) and hedges’ isolation (connected vs. isolated hedges) from forests as well as microhabitat conditions (percentage of bare ground and width) on trait-specific occurrence of ground-dwelling arthropods, namely spiders and carabids. Arthropods were grouped by habitat specialisation (forest vs. open-habitat species vs. generalists), hunting strategy (web-building or hunting spiders) and dispersal ability (wing morphology of carabids). Spider and carabid assemblage composition was strongly influenced by habitat type and isolation, but not by microhabitat conditions. Activity density of forest species and brachypterous carabids was higher in forest edges compared to hedges, whereas open-habitat species and macropterous carabids showed reverse patterns, with no effects of isolation. Occurrence of generalist carabids, but not spiders, was higher in hedges compared to forest edges. Habitat type and isolation did not affect spiders with different hunting strategy. Microhabitat conditions were less important for spider and carabid occurrence. Our study concludes that on a landscape scale, type of linear woody habitat is more important for arthropod occurrence than isolation effects and microhabitat conditions, depending on traits. Hedges provide refuges for species specialised to open habitats and species with high dispersal ability, such as macropterous carabids. Forest edges enhance persistence of species specialised to forests and species with low dispersal ability, such as brachypterous carabids.

Ecological conditions, flora and vegetation of a large doline in the Mecsek Mountains (South Hungary)

Ecological conditions, flora and vegetation of a large doline in the Mecsek Mountains (South Hungary) Vegetation-environment relationships were investigated in a large doline of the Mecsek Mts (South Hungary). To reveal the vegetation pattern, we collected vegetation data and environmental variables along a 243 m long transect. Atotal of 144 vascular plant species and 4 vegetation types were identified in the doline. We found that both the species composition and the vegetation pattern are significantly influenced by air temperature, air humidity, soil moisture and altitude. Our results confirm the putative temperature and vegetation inversion in the doline.

Rural social–ecological systems navigating institutional transitions: case study from Transylvania (Romania)

Abstract Traditional rural social–ecological systems (SES) share many features which are crucial for sustainable development. Eastern European countries such as Romania, are still rich in traditional cultural landscapes. However, these landscapes are increasingly under internal (e.g., peoples aspirations toward western socioeconomic ideals) and external (institutional changes, globalization of the commodity market, connectivity with other cultures) pressures. Therefore, understanding the ways how traditional SES navigated past and more recent changes is of crucial importance in getting insights about the future trajectory of these systems. Here, we present the rural SES from the Saxon region of Transylvania through the lens of institutional transitions which happened in the past century in this region. We show that the rural SES went through episodic collapses and renewals, their cyclic dynamic being related to the episodic changes of the higher level formal institutions. These episodic collapses and renewals created a social–ecological momentum for the sustainability of these SES. While we recognize that policy effectiveness depends on institutional stability (and institutions are unstable and prone to collapses), maintaining those social–ecological system properties which can assure navigation of societies through the challenges imposed by global changes should be in the heart of every governance system. Such properties includes wide extent of native vegetation, fertile soils, wide range of provisioning ecosystem services, genuine links between people and landscapes and knowledge about the social–ecological systems. These features could provide important capitals and memory elements for the (re)emergence of social–ecological systems (old or new).

The effect of the invasive Asclepias syriaca on the ground-dwelling arthropod fauna.

Abstract The management of natural and seminatural systems often leads to disturbance associated with the appearance of non-native species. The spread of these species is increasing due to global environmental changes combined with local management interventions. These non-native species may establish self-sustaining populations influencing ecosystem functions, including the habitat use of native species. Here we explore the response of diplopods, spider and ant assemblages and the activity-density of individual species to the establishment of the non-native plant species, Asclepias syriaca in a disturbed poplar forest in Hungary. The relationship between the species richness of spiders and ants and the structural features of A. syriaca was weak. We found a significant relationship between the structural features of A. syriaca stands and the density and activity of the diplopod Megaphyllum unilineatum. We explain this relationship by the modified microclimate and litter quality of the habitats invaded by A. syriaca. The species composition of ant and spider assemblages was sensitive to A. syriaca. Asclepias syriaca had a negative local effect on the abundance of two spider species which were common in the studied forest. However, A. syriaca positively influenced the abundance of two ant species, most probably via indirect trophic relationships, as they feed on aphids living on A. syriaca. Our study shows that invasive plants can have mixed effects on local invertebrate assemblages. It is therefore crucial to understand how native assemblages respond to these changes in order to better manage these novel ecosystems and maximize their biodiversity benefits.

Physiological and molecular responses to heavy metal stresses suggest different detoxification mechanism of Populus deltoides and P. x canadensis

Plants have divergent defense mechanisms against the harmful effects of heavy metals present in excess in soils and groundwaters. Poplars (Populus spp.) are widely cultivated because of their rapid growth and high biomass production, and members of the genus are increasingly used as experimental model organisms of trees and for phytoremediation purposes. Our aim was to investigate the copper and zinc stress responses of three outstanding biomass producer bred poplar lines to identify such transcripts of genes involved in the detoxification mechanisms, which can play an important role in the protection against heavy metals. Poplar cuttings were grown hydroponically and subjected to short-term (one week) mild and sublethal copper and zinc stresses. We evaluated the effects of the applied heavy metals and the responses of plants by detecting the changes of multiple physiological and biochemical parameters. The most severe cellular oxidative damage was caused by 30μM copper treatment, while zinc was less harmful. Analysis of stress-related transcripts revealed genotype-specific differences that are likely related to alterations in heavy metal tolerance. P. deltoides clones B-229 and PE 19/66 clones were clearly more effective at inducing the expression of various genes implicated in the detoxification process, such as the glutathione transferases, metallothioneins, ABC transporters, (namely PtGSTU51, PxMT1, PdABCC2,3), while the P. canadensis line M-1 accumulated more metal, resulting in greater cellular oxidative damage. Our results show that all three poplar clones are efficient in stress acclimatization, but with different molecular bases.

Abandonment of crop lands leads to different recovery patterns for ant and plant communities in Eastern Europe

Significant proportion of crop lands have been abandoned as management strategies have changed in Central and Eastern Europe in the past decades. The study of insect versus plant communities in such areas could help us understand how these processes take place, and whether these communities return to a semi-natural state maintained by human activities. Amongst insects ants, as ecosystem engineers, are a perfect target group in this respect. We studied epigaeic ant and plant communities of abandoned old-fields in Romania. Contrary to our expectations, the total number of ant species did not increase with time during succession on old-fields contrary to plants, where an increase was registered in the total number. Disturbancetolerant ant species dominated the ant communities throughout the successional gradient, while in the case of plants a transition was found from weed-dominated to semi-natural communities. The diversity of both ant and plant communities increased after the 1-year stage, but the patterns were different. While a return to semi-natural state could be observed in plants during old-field succession, such a definite change did not occur in ants. This might be caused by the landscape context: the lack of connectivity of old-fields to larger natural areas. While plant propagules of semi-natural and natural habitat species can still successfully colonize the old fields even under such conditions, ant colonizers are mainly disturbance-tolerant species typical for agricultural areas, which can be hardly replaced by typical grassland species. Our findings underline the existence of important discrepancies between plant and ant community succession, mostly treated as paralleling each other. This is the first study to handle the effect of abandonment on ant and plant communities simultaneously in Eastern Europe.

Functioning of Ecotones — Spiders and Ants of Edges Between Native and Non-Native Forest Plantations

ABSTRACT: Habitat edges are regarded as important components of heterogeneous landscapes. Diverse theories exist about the diversity and functional role of edges, and no generalisation have been possible so far, thus case studies are important for better understanding the landscape scale processes. Forest management highly modified the structure and tree species composition of the European forests. The sylvicultural intensification resulted in the rise of the proportion of non-native, intensively managed forest stands. In the present study we explore the response of spider and ant assemblages to forest stand type and the edge effect between native poplar and nonnative conifer plantations in Hungary. We applied pitfall traps to sample the ground-dwelling spiders and ants. Four plots consisting of the two forest types and the transition zones between them were selected. Five transects for each replicated plot were sampled. We identified the significant indicator species of the different habitat types. We found significant differences in the species richness (i.e. number of species) of ants and spiders of the different habitat types. We detected intermediate spider species richness at the edge indicating that edges separate a higher quality habitat from one that has lower resource quality; however, the species richness of ants was the highest at the edge and did not differ between the two forest types. The positive impacts of edge was found due to presence of generalist and grassland species at the edge and presumably edges separate patches that provide complementary resources also increasing the number of ant species. Our results indicate that forest type affects the species compositions of ground-dwelling spiders and ants. Our study also shows that habitat type had a major effect on the species richness and composition of spider and ant assemblages, suggesting that local forestry management plays a crucial role in preserving the native invertebrate fauna of forests.

The effects of habitat parameters and forest age on the ground dwelling spiders of lowland poplar forests (Hungary)

Forest management has highly modified the structure of the European forests. Harvesting and post-harvest regeneration leads to a simplified forest structure. Our main objective was to detect the effects of habitat structure and forest age on the ground-dwelling spider diversity and assemblage composition of poplar forests at the Hungarian Great Plain. Our results demonstrate that the rarefaction diversity and the number of forest specialists closely correlated with the structural parameters of the forest floor, however, the age and canopy closure did not influence these parameters. According to redundancy analysis, the composition of spider assemblages was determined solely by habitat structure, with habitat structure having a major effect on the species composition and diversity of spider assemblages. A direct effect of forest age on the spider assemblages was not detected, due to the presence of different habitat types in the surrounding landscape, which may serve as suitable habitats for source-populations of spiders with different habitat requirements. Our results highlight the importance structural complexity of forests for maintaining forest spider diversity and preserving the regional species pool of spiders.

The effect of forest age and habitat structure on the ground‐dwelling ant assemblages of lowland poplar plantations

Intensive management causes significant changes to the habitat structure of forest stands and threatens forest specialist insect species. To assess and counteract the effect of periodic intensive forestry interventions, such as clear‐cutting and reforestation, it is important to adequately quantify the recovery rate and composition of the native biota. We aimed to characterize the above parameters for ant assemblages in forests with different structure and age. Epigeic ant assemblages were studied using pitfall traps in young (6–10 years old), middle‐aged (23–26 years old) and mature (35–37 years old) poplar forest plantations in the Kiskunság region of Hungary. Species richness of ant assemblages and the abundance of nonforest ants did not differ among the age classes. The abundance of forest specialist ants was, however, higher in middle‐aged and mature stands compared with young plantations. The assemblage composition of ants significantly correlated with habitat structure and forest age. We conclude that nonforest ant species can persist throughout the entire forestry cycle in poplar plantations with moderate tree density. The present study suggests that forest age and habitat structure together shape the ant assemblages of lowland poplar plantations.