Natural habitat edges are known to influence the vegetation structure, the microclimate and thereby the invertebrate assemblages. We studied the spiders of two forest edges in the forest-steppe zone of the Great Hungarian Plain (Site 1: a dense juniper shrub — open grassland and Site 2: a juniper and poplar forest — open grassland edge, respectively). The spider assemblages were sampled with pitfall traps arranged in 5 × 20 grid at the habitat edges. Observed and estimated species richness was higher for the grasslands than for the forests. Renyi’s diversity ordering was applied to compare species diversity. The results showed that the grasslands were more diverse in terms of spider species than the forests. The composition of spider assemblages was significantly different between the two habitat types. At Site 2, a higher number forest specialists penetrated into the grassland. Presumably this was due to the shading effect of the nearby poplar trees. Constrained ordinations also revealed a strong influence of the neighbouring poplar trees and vegetation structure on the spider assemblages. No exclusively edge associated species were found on either of the two sharp forest edges.
Authors:F. Samu, F. Kádár, G. Ónodi, M. Kertész, A. Szirányi, É. Szita, K. Fetykó, D. Neidert, E. Botos and V. Altbäcker
Recent environmental and land use changes have made wildfires more frequent in natural habitats of the Kiskunság Sand Ridge on the Hungarian Plain. In a study initiated 2.5 years after an extensive fire that destroyed half of the area of a sand grassland — juniper, poplar forest steppe habitat, we assessed the effects of fire on two generalist arthropod groups: spiders and carabid beetles, as well as on the vegetation. Utilizing the natural experiment situation, samples were taken by pitfalls and suction sampling during a 1.5 years period in four 1 ha blocks, two of which were on the burnt part of the habitat, and two in the unburnt control. At the time of the investigation, in the burnt area the vegetation in the grass layer showed a quick but not complete recovery, while the canopy layer of the juniper bushes burnt down with no sign of regeneration. Carabid beetles and spiders showed differences in recovery after fire. In the carabid assemblages of the burnt parts — compared to the unburnt control — there were over three times more beetles, out of which significantly more represented the macropterous life form and granivorous feeding strategy. There was a higher ratio of pioneer species and a simplified assemblage structure in the burnt area, which meant that the conservation value of the carabid assemblage became lower there. In contrast, for the spider assemblage quantitative changes in abundance and species numbers were not significant, and the differences in species composition did not lead to a decrease in conservation value. Spider species in the burnt plots could not be described as pioneer species, rather they had ecological characteristics that suited the changed vegetation structure. Comparing the two groups, to repopulate the burnt areas, dispersal abilities proved to be more limiting for carabids. However, in both groups a strong assemblage level adaptation could be observed to the postfire conditions. In spiders, species with a stratum preference for the grass layer prevailed, while in carabids individuals with granivore strategy gained dominance. Thus, despite the differences in their speed, basically both assemblages tracked vegetation changes. The effect of future fires will depend on their scale, as well as land-use practices, such as grazing, that interact with fire frequency and recovery. If extensive fires in the future permanently change the vegetation, then it would also lead to a fundamental change in the arthropod fauna.
Survey of aphids on dicotyledonous herbaceous plants along the Hungarian highways on 33 sampling points revealed the presence of 14 aphid species on gymnosperm trees. The most frequent conifer species was: Pinus nigra J. F. Arnold 1785 (21 locations) followed by Pinus sylvestris L.1753, Picea abies (L.) H. Karst. (4 locations), Juniperus communis L. 1753 (3 locations) and Juniperus virginiana L. 1753 (1 location), Thuja occidentalis L.1753 (2 locations), Thuja plicata Donn ex D. Don (1 location).
Eulachnus agilis (Kaltenbach, 1843) was the most frequently collected aphid species on Pinus nigra, followed by Cinara brauni Börner, 1940, Cinara schimitscheki Börner, 1940, Eulachnus rileyi (Williams, 1911) and Cinara acutirostris Hille Ris Lambers, 1956. The less frequent Cinara species was Cinara piniphila (Ratzeburg, 1844) which is a new record for the Hungarian fauna. Pinus sylvestris accommodated three aphid species: Cinara intermedia Pašek, 1954 was the most frequent, followed by Cinara pinea (Mordvilko, 1895) and Eulachnus agilis. Picea abies accommodated Cinara piceae, Cinara pruinosa (Hartig, 1841), Cinara piceicola (Cholodkovsky, 1896) and Sacchiphantes abietis L. 1758. Juniperus communis and J. virginiana most frequently hosted Cinara juniperi (De Geer, 1773). Eulachnus agilis occurred once on Juniperus communis. A single aphid species Cinara tujafilina was found on Thuja occidentalis and Thuja plicata.
is considered an important medicinal plant by the local population of Balochistan, Pakistan. The species is facing a grave threat by a parasitic and epiphytic angiosperm, dwarf mistletoe,
(DC.) M. Bieb. (Viscaceae). The methanolic extract of
was studied for its chemical composition and biologically active compounds for the first time. The extract was assayed for antibacterial, antifungal, phytotoxic, cytotoxic and insecticidal activities. The antibacterial and antifungal activities of the extract were determined against ten bacterial and ten fungal strains by agar well diffusion and disc diffusion assay. The extract was highly effective against three bacteria
Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis
and a fungus
. The phytotoxic effects showed that it was extremely toxic for
. It showed high cytoxicity for brine shrimps at all concentrations and was found to be significantly cytotoxic against
when checked by flow cytometer. However, the extract was not effective against the pests tested.
Authors:T. Seregélyes, Zs. Molnár, Á. Csomós and J. Bölöni
Regeneration potential is regarded as a kind of functional indicator, which is applied for the assessment of the habitat quality and a kind of nature conservation value. In this context “quality” does not refer to the actual state but possibilities for the future. During the MÉTA project, regeneration potential have been recorded on the scale of the quadrates (35 km
, 2,813 quadrates in Hungary), for each habitat of the quadrate (ignoring some featureless habitats). We have estimated three different kinds of regeneration potential: on spot, on the place of neighbours and on old-fields open water, bare rock. The categories used were: good regeneration ability, moderate, low, or there is no place for regeneration.Values of regeneration potential on spot are usually rather high. Habitats with the highest regeneration potential are the aquatic ones, shrub vegetation, halophytic vegetation, marshes, grasslands with woodland origin, sand poplar-juniper woodlands, and the poorest is the regeneration potential of the forest steppe woodlands. Lower are the values of the regeneration potential of each vegetation type on the place of the neighbours. Relatively easily spread onto the neighbouring vegetation patches the halophytic habitats, poplar-juniper woodlands, the secondary shrub vegetation, some aquatic habitats, certain riverine vegetation types and marshes. Moderate or lower is this value of this regeneration potential category for the xeric highland woodlands, rocky habitats, xeric and mesic lowland woodlands, grasslands with woodland origin and some fen vegetation types. In spite of the rather low values calculated for the whole country, the following habitats regenerate relatively well on old-fields, open water or rock surfaces, or in abandoned vineyards: the dry secondary shrub vegetation, poplar-juniper woodlands, Scots pine woodlands, halophytic habitats, some aquatic habitats and marshes. Most habitats regenerate poorly, for example, the zonal woodlands. Never or barely regenerate on old-fields: some fen habitats, the steppe oak woodlands, mesic lowland woodlands, some rock habitats, acidophilous woodlands, the zonal woodlands, the rock and sand coniferous woodlands.When comparing the values of regeneration potential on spot, on the place of the neighbours and on old-fields, most striking is the fact that the least habitats have moderate or high regeneration ability in case of the third kind of regeneration potential, and regeneration ability on adjacent vegetation patch represent a transitional state from this aspect. Some of the edaphic habitats are quite mobile (e.g. halophytic, marsh or certain fen habitats), while others migrate only rarely (rock or other fen vegetation types). Some habitats though regenerate admirably on spot, yet never invade new areas; for instance, rock vegetation, acidophilous woodlands, grasslands with woodland origin. Others has almost the same regeneration potential values on spot as on the place of the neighbours, e.g. some steppe woodlands and shrub habitats on their own clearings, or some habitats of secondary origin. Certain rock habitats, some fen and riverine vegetation types and some of the close woodlands regenerate well on spot, but almost never on old-fields. There are some habitats, which has high regeneration potential on the place of the neighbours, but has low values for the old-fields. Most of them are closed woodlands, shrub and certain fen habitats.According to our expectations, the experience gained during the MÉTA mapping will give an impulse to the study on regeneration potential.
Authors:C. Ricotta, A. Stanisci, G. C. Avena and C. Blasi
.A. Hatfield, J. David and P.T. Hraber. 1996. Detection of critical densities associated with pińon-juniper woodland ecotones. Ecology 77:805-821.
Detection of critical densities associated with pińon-juniper woodland ecotones