László & Tóthmérész (2012) Insect Conservation & Diversity

László, Z., Tóthmérész, B. (2012), Landscape and local effects on multiparasitoid coexistence. Insect Conservation and Diversity. doi: 10.1111/j.1752-4598.2012.00225.x



Abstract

1. When resources are spatially fragmented, strength of competition between species is diminished by alternative patterns of resource use and parasitoids of the same host species become potential competitors. The coexistence of competing species in spatially fragmented habitats may be achieved, however, due to niche partitioning and alternative responses to patch characteristics. To evaluate responses to resource patterns facilitating coexistence, we examined the resource use patterns of four parasitoid species (Orthopelma mediator, Pteromalus bedeguaris, Torymus bedeguaris and Glyphomerus stigma) of the gall inducer Diplolepis rosaeat both landscape and local scales.
2. Parasitoid species of rose gall communities behave differently at landscape and local scales. Parasitism rates and parasitoid incidence showed correlations with local characteristics in some cases, with landscape characteristics in others and, in some other cases with both.
3. Species responses to the examined characteristics depend rather on life history traits of parasitoids than on their frequency within the community. The examined parasitoids responded differently to landscape and local characteristics, while their phenology corresponded with their responses. Species emerging earlier in spring (O. mediator and P. bedeguaris) responded only to local variations, while later emerging species (T. bedeguaris and G. stigma) were sensitive to landscape characteristics as well.
4. Differences between species-specific and overall responses highlight the importance of species characteristics when considering multiparasitoid communities, and support both fine and coarse partitioning between different species coexisting in the community.

Keywords
Coexistence, land use, landscape fragmentation, parasitism rate, parasitoid incidence, tritrophic system

Somodi et al. (2012) Journal of Vegetation Science

Somodi, I., Molnár, Z., Ewald, J. (2012): Towards a more transparent use of the potential natural vegetation concept – an answer to Chiarucci et al. Journal of Vegetation Science, 23: 590–595. doi: 10.1111/j.1654-1103.2011.01378.x

Abstract
In this paper, the concerns of Chiarucci et al. () regarding use of the potential natural vegetation (PNV) concept are addressed, as voiced in the forum section of the Journal of Vegetation Science. First, we rectify some unfounded expectations concerning PNV, including a relationship with prehuman vegetation and phytosociology. Second, we point out issues that pose considerable challenges in PNV and require common agreement. Here, we address the issue of time and disturbance. We propose to use the static PNV concept as a baseline, a null model for landscape assessment and in comparisons. Instead of changing the PNV concept itself, we introduce a new term, potential future natural vegetation (PFV) to cover estimations of potential successional outcomes. Finally, we offer a new view of PNV with which we intend to make the use of PNV estimates more transparent. We formalize the PNV theory into a partial cause-effect model of vegetation that clearly states which effects on vegetation are factored out during its estimation. Further, we also propose to assess PNV in a probabilistic setting, rather than providing a single estimate for one location. This multiple PNV would reflect our uncertainty about the vegetation entity that could persist at the locality concerned. Such uncertainty arises from the overlap of environmental preferences of different mature vegetation types. Thus reformulated, we argue that the PNV concept has much to offer as a null model, especially in landscape ecology and in site comparisons in space and time.


Keywords
Ecological baseline, Landscape comparison, Multiple probabilistic PNV, Null model, Potential future natural vegetation, Predictive modelling

Somodi et al. (2012) Biological Conservation

Imelda Somodi, Andraž Čarni, Daniela Ribeiro, Tomaž Podobnikar (2012): Recognition of the invasive species Robinia pseudacacia from combined remote sensing and GIS sources. Biological Conservation, 150 (1) 59–67. DOI 10.1016/j.biocon.2012.02.014


Abstract
Monitoring the spread of invasive species is crucial for nature conservation; however regularity can only be assured if cost-effectiveness can be achieved. We aimed at testing low-cost remote sensing sources and simple methodology for recognising the invasive species Robinia pseudacacia and thus founding a monitoring scheme. A study area with mixed wooded stands containing R. pseudacacia has been selected for this purpose in NE Slovenia. Four different sources (Landsat ETM and airborne orthophotos from summer and spring) were tested together with a filtering for forested areas. Filtering was based either on Landsat information or on a forest polygon layer as alternatives. Generalised linear models were constructed in a training window within the study area to establish a statistical rule of recognition for the species based on spectral information. Models were tested both within and outside the training window for accuracy. As means of accuracy assessment both the well-established AUC and the specially adapted Jaccard index have been applied.
The best and most reliable recognition was achieved by using the spring orthophoto, in which the species was captured in flower, combined with a GIS filtering by a forest vector layer. The superiority of this combination was especially striking when tested over the full study area. The Jaccard index appeared to be more sensitive in discrimination between models. Thus we conclude that even spectrally less detailed data sources may provide a basis for successful monitoring if the phenology of the target species is also considered.


Keywords
AUC, Cost-effectiveness, GLM, Landsat, Orthophoto, Phenology

Aszalós et al. (2012) European Journal of Forest Research

Réka Aszalós, Imelda Somodi, Kata Kenderes, János Ruff, Bálint Czúcz, Tibor Standovár (2012): Accurate prediction of ice disturbance in European deciduous forests with generalized linear models: a comparison of field-based and airborne-based approaches. DOI 10.1007/s10342-012-0641-6


Abstract
We analyzed an ice disturbance event of deciduous forests in Hungary by Generalized Linear Models (GLM). Two statistical models were generated: the first model was based on a disturbance map created from a series of aerial photographs, and the second model was based on a map created by half-year-long intensive field work. The second map was considered as the reference map of ice disturbance. Our hypothesis was that the predictive power of the field-based statistical model would be significantly higher than that of the aerial photo-based model on the reference map. Elevation, slope, aspect, mixture ratio of beech, height of the dominant tree species and their interactions were used in the two (aerial photo- and field-based) GLMs as explanatory variables. The accuracy of the models was measured by the AUC (Area under the ROC curve) values. Sensitive area maps of ice disturbance were generated by both models. Our hypothesis was definitely rejected. Both models performed high predictive accuracy (median AUC > 0.9) with no significant difference in the prediction capacity regarding the reference ice disturbance pattern. Our study demonstrates that ice damage can effectively be predicted if remote sensing interpretation is coupled with GLM as predictive model.

 

Keywords
Forest damage, GLM, Susceptibility assessment, Probability map, Variable interactions

Podani & Schmera (2012) Ecography

Podani, J. and Schmera, D. (2012): A comparative evaluation of pairwise nestedness measures. Ecography, 35: 889–900. doi: 10.1111/j.1600-0587.2011.07319.x



Abstract

This paper deals with nestedness measures that are based on pairwise comparisons of sites, evaluates their performance and suggests improvements and generalizations. There are several conceptual and technical criteria to judge their ecological applicability. It is of primary concern whether the measures 1) have a clear mathematical definition, 2) are influenced by the ordering of the data matrix, 3) incorporate similarity alone or similarity together with a dissimilarity component, 4) consider site pairs with identical species number negatively or positively, 5) show sensitivity to small changes in the data, and 6) are not vulnerable to type I and type II error rates. We performed a detailed comparison of the nestedness metric based on overlap and decreasing fill (NODF), the percentage relativized nestedness and the percentage relativized strict nestedness functions (PRN and PRSN, respectively), based on analytical results as well as on artificial and actual examples. We show that NODF is in fact the average Simpson similarity of sites with different species totals, and that its value depends on how the matrix is actually ordered. NODF is modified to always produce the maximum possible result (NODFmax), independently of the order of columns and rows. Being based on similarities, NODF and NODFmax overemphasize the overlap component of nestedness and underrate richness difference which is also an important constituent of nested pattern in meta-community data. This latter feature is reflected adequately by PRN and PRSN. However, PRSN is similar to NODF and NODFmax in sharing the disadvantages that 1) complete agreement and segregation in species composition are not distinguished, 2) a random matrix can have a higher value than truly nested patterns, and 3) they are ill-conditioned statistically. These problems are rooted mostly in that site pairs with tied totals affect the result negatively. We emphasize that PRN is free from these difficulties. PRN, PRSN, and NODFmax, together with mean Simpson similarity exhibit highly similar statistical performance: they are resistant to type I and type II errors for the less constrained null models, although there are subtle differences depending on matrix fill and algorithm of randomization. The most constrained null model, with all marginal totals fixed, makes all statistics more sensitive to type I errors, although vulnerability depends greatly on matrix fill.

Szabó et al. (2012) Journal for Nature Conservation

Szilárd Szabó, Tibor Novák, Zoltán Elek (2012): Distance models in ecological network management: A case study of patch connectivity in a grassland network. Journal for Nature Conservation 20(5): 293–300.

Abstract

Landscape connectivity is a key issue of nature conservation and distance parameters are essential for the calculation of patch level metrics. For such calculations the so-called Euclidean and the least cost distance are the most widespread models. In the present work we tested both distance models for landscape connectivity, using connectivity metrics in the case of a grassland mosaic, and the ground beetle Pterostichus melas as a focal species. Our goal was to explore the dissimilarity between the two distance models and the consequent divergence from the calculated values of patch relevance in connectivity. We found that the two distance models calculated the distances similarly, but their estimations were more reliable over short distances (circa 500 m), than long distances (circa 3000 m). The variability in the importance of habitat patches (i.e. patch connectivity indices) was estimated by the difference between the two distance models (Euclidean vs. least cost) according to the patch size. The location of the habitat patches in the matrix seemed to be a more important factor than the habitat size in the estimation of connectivity. The uncertainty of three patch connectivity indices (Integral Index of Connectivity, Probability of Connectance and Flux) became high above a habitat size of 5 ha. Relevance of patches in maintaining connectivity varied even within small ranges depending on the estimator of distance, revealing the careful consideration of these methods in conservation planning.

Keywords
Distance models; Matrix effect; NDVI; Patch connectivity; Pterostichus melas

Garay et al. (2012) Journal of Theoretical Biology

József Garay, Zoltán Varga, Tomás Cabello, Manuel Gámez (2012): Optimal nutrient foraging strategy of an omnivore: Liebig's law determining numerical response. Journal of Theoretical Biology 310 (7). 31–42.

Abstract

The paper is aimed at a theoretical explanation of the following phenomenon. In biological pest control in greenhouses, if an omnivore agent is released before the arrival of the pest, the agent may be able to colonize, feeding only on plant and then control its arriving prey to a low density. If the pest arrives before the release of the agent, then it tends to reach a high density, in spite of the action of the agent. This means that according to the initial state, the system displays different stable equilibria, i.e. bistable coexistence is observed. Based on the biological situation, the explaining theoretical model must take into account the stoichiometry of different nutrients and the optimal foraging of the omnivore agent. We introduce an optimal numerical response which depends on the optimal functional responses and on the ‘mixed diet–fitness’ correspondence determined by ‘egg stoichiometry’, in our case by Liebig's Law; moreover we also study the dynamical consequences of the latter when the plant is “inexhaustible”. In our model, we found that under Holling type II functional response, the omnivore–prey system has a unique equilibrium, while for Holling type III, we obtained bistable coexistence. The latter fact also explains the above phenomenon that an omnivore agent may control the pest to different levels, according to the timing of the release of the agent.

Keywords

Ecological stoichiometry; Imperfectly substitutable resources; Liebig's Law; Numerical response; Omnivory

Pinke et al. (2012) Applied Vegetation Science

Pinke, G., Karácsony, P., Czúcz, B., Botta-Dukát, Z., Lengyel, A. (2012), The influence of environment, management and site context on species composition of summer arable weed vegetation in Hungary. Applied Vegetation Science, 15: 136–144. doi: 10.1111/j.1654-109X.2011.01158.x


Abstract
Questions: Which environmental and management factors are the most important determinants of arable weed species composition in intensively farmed areas across an area of 93 000 km2? Does the relative importance of environmental and management factors depend on plot location within fields (centre or edge)?
Location: Hungary.

Methods: The abundance of late-summer weed flora and 25 environmental, management and site context factors were measured in 243 maize, sunflower and stubble fields representing the entire country. Data were analysed by redundancy analysis (RDA) after backward variable selection. The gross and net effect on weed species composition were calculated for each variable. Variation partitioning based on RDA was used to assess the relative effects of the three groups of explanatory variables.
Results: The net effects of 24 variables on species composition were significant, explaining 25% of the total variation in species data. Most variation in species composition was explained by plot location, which was followed by temperature, crop type, precipitation, soil texture, neighbouring habitat, altitude, soil pH, sodium and potassium content of the soil. Variation partitioning revealed that environmental variables accounted for twice more variance than management variables, but the relative impact of management variables was larger in field cores than in field edges.
Conclusions: Our results suggest that even for intensified agriculture the effects of environmental factors are of greater importance than management factors on summer arable weed composition in a country-wide context. The effects of intensive crop management decrease towards the field periphery.


Keywords
Agroecology; Agro-ecosystem; Arable fields; Climate; Crop; Field edges; Plant community; Soil; Weed flora

Engloner (2012) Ecological Indicators

Attila I. Engloner (2012): Alternative ways to use and evaluate Kohler's ordinal scale to assess aquatic macrophyte abundance. Ecological Indicators 20: 238-243.


Abstract
To assess numerical information on the aquatic vegetation of running water bodies, the ‘Kohler method’, a five-level descriptor scale estimating the relative abundance of species in river sections as survey units has been frequently used. Although this scale is ordinal without any information on differences between the states, data are often evaluated by arithmetic operations as if they were on the ratio scale. Metrizing ordinal information may facilitate correct data evaluation; however, the outcome highly depends on mathematical procedures applied to the data set.
This paper demonstrates that if ordinal data are analyzed by ordination methods suited to this scale type, then results primarily reflect presence/absences. To the contrary, additional information was added to Kohler's scale when the applied analyses used values on ratio scales; therefore they provided inappropriate data evaluation.

Four different conversion methods (the use of 1–5 values, the third power, the mean values of Braun-Blanquet cover classes and the replacement of ordinal states by ranks) were applied to reveal how the conversion procedures determine the intervals between the substituting metric values and the level of importance given to species frequency and abundance. When ordinal scale was substituted by numbers 1–5 and ranks, frequency of species was taken greatly into account. After cubic conversion the large values became considerably overemphasized, therefore species occurring in a few (or very few) survey units with high abundance values were considered more dominant than less abundant but frequently present ones. The mean values of Braun-Blanquet's cover classes gave large ordinal scores and the frequent species to have substantive representation.
The results demonstrate that conscious choice of intervals between the scores is inevitable; otherwise one generates unknown or misleading differences in species abundance. Although every researcher assessing aquatic macrophytes by Kohler's method surely has an idea on the differences between the applied scores, the use of identical, widely accepted scale substitution is prerequisite for reliable comparison.


Keywords
Macrophyte indices, Metrizing ordinal information, Ordinal scale, River ecosystems

Lengyel et al. (2012) Acta Botanica Croatica

Attila Lengyel, Dragica Purger, Janos Csiky (2012): Classification of mesic grasslands and their transitions of South Transdanubia (Hungary). Acta Botanica Croatica 71(1): 31-50.

Abstract
Relevés from meadows and pastures of South Transdanubia (Hungary) are evaluated by clustering and ordination methods. The relevé selection focused on the Arrhenatheretalia order but its transitions towards other types were also included. The groups of relevés are delimited and described according to differential, dominant and constant species. Ecological conditions of the groups were compared using indicator values. Nine groups were distinguished, four of them belonging strictly to the order Arrhenatheretalia. Each alliance of Arrhenatheretalia presented in the study area (Cynosurion, Arrhenatherion) was represented by two groups. Groups from these two alliances are separated along a light gradient, while groups of the same alliance differ in nutrient values. Within Cynosurion, the nutrient-poor group cannot be identified unambiguously as any syntaxa previously known from Hungary. The nutrient-rich Cynosurion meadows are similar to Lolio–Cynosuretum, however, they show a stronger relationship with wet meadows. Within Arrhenatherion, Pastinaco–Arrhenatheretum is recognised as a hay meadow of nutrient-rich soils. The other meadow type is similar to Filipendulo–Arrhenatheretum, thus raising syntaxonomical problems. There are transitional groups towards semi-dry and wet meadows, one dynamic phase and one outlier group among the other five clusters.


Keywords
Vegetation survey, Meadows, Pastures, Cluster analysis, Indicator values, Phytosociology, Ordination, Syntaxonomy

Turic et al. (2012) Aquatic Insects

Nataša Turić, Enrih Merdić, Branimir K. Hackenberger, Željka Jeličić, Goran Vignjević, Zoltán Csabai (2012): Structure of aquatic assemblages of Coleoptera and Heteroptera in relation to habitat type and flood dynamic structure. Aquatic Insects 34 (sup. 1): 189-205.

Abstract

The abundance and taxonomic composition of the aquatic insect fauna were investigated, with focus on adult water bugs, water beetles and water scavenger beetles (Heteroptera: Nepomorpha and Gerromorpha, and Coleoptera: Hydradephaga and Hydrophilidae) in two different freshwater habitats: (1) a periodically flooded area of the Special Zoological Reserve in Kopački rit Nature Park, Croatia; and (2) melioration canals in the wider area of the Nature Park during 2005. Aquatic insects are generally abundant in various water systems, including floodplains that are exposed to water level fluctuations. Our aims were (1) to determine abundance and species richness in relation to habitat type; (2) to determine the influence of high flood peaks and oscillations during high water levels on the diversity of aquatic Coleoptera and Heteroptera in the flooded area; and (3) to identify characteristic species associated with each habitat type. We collected 71 species; 41 were captured at canals and 64 at the flooded area. Diversity of the two habitat types varied depending on the months but there were remarkable differences in species pool and their abundance. Both high and low water levels as well as oscillations during high water levels had major influence on species assemblages at the flooded area. Diversity of aquatic Coleoptera and Heteroptera was higher when the water level decreased after high water level peaks. A total of 11 species fulfilled the criteria for specificity and were sufficiently abundant to be suitable species characteristic for these two habitats. A higher proportion of significant characteristic species was present in the flooded area than in the canals. The presence of two Red List species of water beetles (Graphoderus bilineatus De Geer, 1774 and Berosus geminus Reiche et Saulcy, 1856) and nine significant characteristic species at the flooded area clearly indicates that the contribution of floodplains in maintaining freshwater biodiversity is not only important regionally but also at the international level. Also, our results suggest that the power of high water levels is an important factor that can be used in analyses on aquatic Coleoptera and Heteroptera assemblages, showing the uniqueness of large floodplain areas.

Keywords

canal habitat, flooded habitat, water levels, flood intensity, significant species, Kopački rit Nature Park

Szivák & Csabai (2012) Aquatic Insects

Ildikó Szivák, Zoltán Csabai (2012): Are there any differences between taxa groups having distinct ecological traits based on their responses to environmental factors? Aquatic Insects 34 (sup. 1): 173-187. DOI: 10.1080/01650424.2012.643052

Abstract

The aim of this study was to explore the differences between taxa groups with different ecological strategies for persistence, regarding their responses to environmental factors and seasonal variation. We studied the relationship between the seasonal patterns and habitat attributes of the Ephemeroptera, Plecoptera, Trichoptera (EPT) and the Colepotera, Heteroptera (CH) assemblages. Sampling was carried out in May, July and October of 2009. Samples were taken according to the AQEM protocol at 10 stream sections in the Mecsek Mountains. Based on multivariate analyses (RDA, pRDA), distinctive differences were found between the EPT and the CH taxa groups regarding their response to local chemical variables and variables describing the riparian vegetation. The measured environmental variables had a higher relative influence on the distribution patterns of EPT and CH assemblages than spatial variation of species patterns. The physical structure of aquatic habitats, including the type of bedrock, had greater effects on CH than EPT patterns, whereas the structure of riparian vegetation was more important for EPT than CH. Average density and average taxon richness of EPT were seasonally variable, but CH assemblages were not.

Keywords

aquatic insect assemblages, near-natural headwaters, environmental variables, spatial and seasonal distribution, Partial Redundancy Analysis

Bereczki et al. (2012) Aquatic Insects

Csaba Bereczki, Ildikó Szivák, Arnold Móra, Zoltán Csabai (2012): Variation of aquatic insect assemblages among seasons and microhabitats in Hungarian second-order streams. Aquatic Insects 34 (sup1): 103-112. DOI:10.1080/01650424.2012.643032



Abstract
The assemblages of aquatic insects are important members of water ecosystems. Based on former studies among the most important factors structuring the assemblages are numerous abiotic ones, such as the sort and the particle size of the substratum. Most of the sampling protocols, e.g. AQEM, determine microhabitats based on those. Nevertheless, we have no information yet about whether or not these different, precisely determined microhabitats have different assemblages. In this study we compared the aquatic insect assemblages of different microhabitat types in three seasons using ADONIS and linear discriminant analyses. We proved that seasonal changes of abiotic factors had a major role in structuring the assemblages. In spring and summer the assemblages differed significantly, however, in autumn no significant differences were found. We supposed that the variation among the assemblages was due to the abundance patterns of frequent species instead of the presence of rare or sparse species. The indicator species analyses also corroborated this suppososition while symmetrical indicator species were not found.


Keywords
microhabitat, seasonality, aquatic insects, linear discriminant analysis, ADONIS, indicator species

Csabai et al. (2012) Naturwissenschaften

Zoltán Csabai, Zoltán Kálmán, Ildikó Szivák and Pál Boda (2012): Diel flight behaviour and dispersal patterns of aquatic Coleoptera and Heteroptera species with special emphasis on the importance of seasons. Naturwissenschaften 99(9): 751-765. doi: 10.1007/s00114-012-0957-6.

Abstract

Dispersal flight is the most important and almost the only way for primary aquatic insects to find new water habitats. During a 30-week-long project, we monitored the flight dispersal behaviour of aquatic beetles and bugs with using highly and horizontally polarizing agricultural black plastic sheets laid onto the ground. Based on the flight data of more than 45,000 individuals and 92 species, we explored and described eight different diel flight activity patterns. We found that seven of eight dispersal patterns are consistent with the previous knowledge, while three conspicuous mass dispersal periods can be identified as in the mid morning and/or around noon and/or at nightfall. As an exception, we found a ‘daytime’ pattern occurred exclusively in spring, in which mass dispersal can be seen from mid morning to late afternoon. In contrast to previous studies, we emphasize here that the seasonality has to be considered in evaluation of the diurnal flight activity. According to the seasons, a ‘three code sign’ was proposed to indicate the diel dispersal flight behaviour of a species for a year. Most of the species utilize different diel activity patterns in different seasons. In spring, the daytime pattern was the preferred type, but in summer and autumn, the evening types were the most popular patterns. We stated that the seasonal change of air temperature has a crucial role in that a pattern could be manifested in a given season or not and brings a need to change the diel dispersal pattern among seasons.

Keywords

Aquatic insect dispersal behaviour, Diel flight activity, Diurnal dispersal patterns, Pattern shift among seasons, Air temperature dependency

 

 

Kőrösi et al. (2012) Insect Conservation and Diversity

KŐRÖSI, Á., BATÁRY, P., OROSZ, A., RÉDEI, D. and BÁLDI, A. (2012): Effects of grazing, vegetation structure and landscape complexity on grassland leafhoppers (Hemiptera: Auchenorrhyncha) and true bugs (Hemiptera: Heteroptera) in Hungary. Insect Conservation and Diversity, 5: 57–66. doi: 10.1111/j.1752-4598.2011.00153.x


Abstract
1. Agricultural intensification is a major cause of biodiversity loss in European farmlands. Grasslands are particularly important habitats for the conservation of rich insect assemblages of Central and Eastern Europe. Although regular grazing or mowing of these grasslands is required to maintain diversity, there is no information about how such management and other factors influence Hemiptera assemblages.
2.  We studied leafhopper and true bug assemblages in semi-natural grasslands in three regions of the Great Hungarian Plain. We investigated how local vegetation factors and landscape complexity influence assemblages and whether they interact with management effects.
3.  Seven pairs of intensively (>1 cow/ha) versus extensively (∼0.5 cow/ha) grazed pastures were sampled in each region by sweep-netting.
4.  Sward height was the most important explanatory factor for leafhoppers (84 species, 27264 individuals), as it increased both species number and abundance, and influenced assemblage composition. The extent of grassland surrounding the sample sites negatively affected leafhoppers, whereas extensive grazing decreased abundance and influenced composition. True bug assemblages (140 species, 6656 individuals) were positively affected only by mean sward height, whereas regional differences determined the community composition of both taxa.
5.  We conclude that vegetation structure is the primary factor shaping Hemiptera communities and that the various types of grasslands studied are all important habitats for the taxon. Therefore, cattle grazing in its current form is beneficial for the rich Hemiptera fauna in lowland pastures of Hungary. However, in some cases, local and landscape factors and great regional differences may confound the effects of grazing, and this must be considered in conservation planning in the future.


Keywords

Abundance; cattle pastures; community composition; grazing intensity; landscape structure; semi-natural grassland; species richness; sward height

Kovács-Hostyánszki & Báldi (2012) Biological Conservation

Anikó Kovács-Hostyánszki, András Báldi (2012): Set-aside fields in agri-environment schemes can replace the market-driven abolishment of fallows. Biological Conservation 152: 196-203.


Abstract
Economic pressures from increased commodity prices and the growing demand for land for biomass plantations led to the abolition of compulsory set-aside fields in the European Union in 2008, affecting ca. 10% of total agricultural area. This area is now managed more intensively, and this is expected to adversely affect farmland biodiversity. Unfortunately, no mitigation of set-aside loss was introduced. Here we examined, whether or not set-aside fields managed in voluntary agri-environment schemes have the potential to improve farmland bird populations, as indicators of farmland biodiversity. We chose one, two and three year-old set-aside fields sown by a grass–legume mixture when established and selected winter cereal fields and semi-natural grasslands in Hungary as control sites. Relative abundance of birds was assessed; species were assigned to feeding guilds and classified according to their European conservation status. Species richness of herbaceous plants, cover of bare ground and vegetation height were used as covariates. Set-aside fields had higher species richness and abundance of birds compared to the adjacent winter cereal fields, similar to semi-natural grasslands. We found a positive correlation between set-aside age and farmland bird species richness and abundance. This can be explained mainly by the altered vegetation, especially the shorter vegetation height from the second year in the set-aside fields. We found no difference in the distribution pattern of species richness and abundance between feeding guilds according to set-aside age and habitat types. The wide scale application of voluntary set-aside management in agri-environment programs therefore has a high potential to mitigate the negative effects from the loss of compulsory set-aside schemes, and thus need the allocation of considerable resources in the forthcoming reformed CAP.


Keywords

Agricultural policy; Farmland bird; Semi-natural grassland; Vegetation structure; Winter cereal

Shapiro & Báldi (2012) Frontiers in Ecology and the Environment

Julie Teresa Shapiro & András Báldi (2012): Lost locations and the (ir)repeatability of ecological studies. Frontiers in Ecology and the Environment 10: 235–23.

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Oborny & Englert (2012) Ecological Modelling

Oborny, B. & Englert, P. (2012) Plant growth and foraging for a patchy resource: a credit model. Ecological Modelling 234: 20-30.


Abstract
Several experiments have demonstrated that plants can adjust their growth pattern to the pattern of resources in the environment, and thus, forage for resources by adaptive plasticity. We review some basic concepts in plant foraging, and suggest new aspects on the basis of individual-based, spatially explicit simulations. Foraging is an iterative process. We describe its elementary step, the “foraging cycle”, and emphasize the importance of time-dependence of the success of foraging. The difference between short vs. long-term success is demonstrated through the example of two plastic growth responses that frequently occur among clonal plant species. We introduce the concept of credit into the study of foraging growth. The plant can use a credit when a temporary resource shortage can be compensated from an external source (from outside the “foraging cycle”, e.g. from storage). Our simulations demonstrate that the availability of credit is decisive in the success of foraging, especially at young genet age. We describe some special challenges met by young plants, and emphasize the importance of empirical research in two fields: (1) to search for age-specific foraging strategies, and (2) to estimate the realistic time window within which considerable selection can act upon a growth response.


Keywords

Patchy environment; Adaptive growth; Phenotypic plasticity; Allocation; Clonal plant; Spatial population dynamics

Oborny et al. (2012) Ecological Modelling

Oborny, B., Mony, C. & Herben, T. (2012) From virtual plants to real communities: a review of modelling clonal plants. Ecological Modelling 234: 3-19.


Abstract
Clonal plants grow by the production of semi-autonomous modules (ramets), and form complex branching structures which may provide communication/resource flow channels between the units. These characteristic features have made clonal plants a challenging subject for spatial modelling. We review the advance of ideas and new directions in theoretical research since the last review (Oborny and Cain, 1997). We place clonal growth models into a general framework of spatial population dynamic models, comparing individual ramets of a clone with individuals in a non-clonal population. We discuss three specificities of clonal spreading: (1) ramets can be physiologically integrated through the network of branching structures; (2) formation of new ramets occurs by the growth of these branching structures which can be directional, following architectural rules; and (3) formation of new ramets can be adjusted to the environment by phenotypic plasticity. We review methods by which these traits have been implemented into models. We summarize model predictions, for the spatial structure and fitness of clonal plants, and link these predictions with existing empirical data. Emphasis is given to the contributions that theoretical studies could provide for experimental studies in the field. We emphasize the following recent major developments: (i) a much better understanding of emergent consequences of various clonal growth rules over broad spatial and temporal scales has been reached. (ii) Links have been found to other complex systems. For example, a key problem of integration vs. splitting of connecting structures has been shown to be closely related to a problem in percolation theory. (iii) Interactions between physiological integration, architectural growth and plastic responses have been demonstrated; research on these interactions has generally shown a large degree of contingency in the effects of these traits. Finally, we outline some areas for future research.


Keywords
Spatial population dynamics, Individual-based models, Architectural rules, Phenotypic plasticity, Division of labour, Adaptive growth

Lengyel et al. (2012) Community Ecology

Attila Lengyel, János Csiky & Zoltán Botta-Dukát (2012): How do locally infrequent species influence numerical classification? A simulation study. Community Ecology 13(1): 64-71.


Abstract

Phytosociological databases are important data sources for a broad scale of ecological investigations. Vegetation samples are traditionally managed and published in tabular format, allowing for handling of the vegetation data in various combinations. Such tables usually comprise relevés originated from the same locality, vegetation type and collected by the same investigator. Nevertheless, these relevés are usually affected by the same bias. In this paper, we demonstrate the importance of the effects acting at the level of the table (i.e., ‘locally’), using the example of species removals from groups of relevés. We examine the effect of the removal of infrequent species on community classification in relation with several data set properties using simulated plot data sampled from simulated coenoclines. A data set comprised groups of relevés (‘tables’), within which relevés are sampled from the same point of the coenocline. Classifications obtained after the removal or permutation of infrequent species occurrences from these tables, after the removal of rare species from randomised tables and without any treatment were compared to a reference classification based on gradient positions of the relevés. The results show that the removal of locally infrequent species helps to recognise the gradient pattern incorporated in the tabular arrangement of relevés if the arrangement of relevés among tables is in accordance with their gradient position. In cases when the grouping of relevés is irrelevant regarding the real underlying pattern, the species removal is disadvantageous. Testing between-table heterogeneity within a data set is an especially successful way of examination of biological relevance of the arrangement of relevés. We conclude that influence of table-level effects is mainly dependent on the pattern which is in accordance with the grouping of plots.

Kulcsszavak
Coenocline, Multivariate analysis, Noise elimination, Phytosociology, Rare species, Vegetation databases

Bátori et al. (2012) Journal of Cave and Karst Studies

Bátori Z., Körmöczi L., Erdős L., Zalatnai M., Csiky J. (2012): Importance of karst sinkholes in preserving relict, mountain and wet woodland plant species under sub-Mediterranean climate: a case study from southern Hungary. Journal of Cave and Karst Studies 74(1): 127-144.


Abstract

Abstract: Species composition and the vegetation pattern of the understory were investigated in different sized solution sinkholes in a woodland area of the Mecsek Mountains (southern Hungary). Vegetation data together with topographic variables were collected along transects to reveal the vegetation patterns on the slopes, and a species list was compiled for each sinkhole. The results indicate that the vegetation pattern significantly correlates with sinkhole size. In smaller sinkholes, vegetation does not change substantially along the transects; in larger sinkholes, however, vegetation inversion is pronounced. We also found that sinkhole size clearly influences the number of vascular plant species, in accordance with the well-known relationship between species number and area. In the forest landscape, many medium-sized and large sinkholes have
developed into excellent refuge areas for glacial relicts, mountain, and wet-woodland plant species.

Erdős et al. (2012) Pakistan Journal of Botany

Erdős L., Méri Á., Bátori Z., Gallé R., Körmöczi L. (2012): North-south facing vegetation gradients in the Villány Mts: A case study on the population and the community level. Pakistan Journal of Botany 44(3): 927-932.

Abstract
The study of gradients can provide basic information about the ecology of plant populations as well as about
community organization. In this study, north-south facing vegetation gradients were investigated in a submediterranean region of South Hungary. Vegetation was examined along five contiguous belt transects, each 200 m long, crossing the mountain ridge or plateau. Plant community sequences were identified visually during field studies. Moreover, community boundaries were delineated objectively, using the moving-split window analysis. In addition, number and size of the population patches were analyzed. This study revealed that mesic forest communities of the northern slopes are replaced by shrubforests and closed rock swards near the ridge, whereas mosaics of shrubforests and open rock swards occur on the southern slopes. Number of significant community boundaries was higher on the southern slopes than on the northern ones. Southern slopes support much more plant species. They have more population patches, which are significantly smaller than patches of the northern slopes. Community sequences along north-south gradients in the Villány Mts are similar to those of the nearby mountainous areas, with one fundamental difference of the xeric grasslands near the ridge. The conclusion of the present paper is that this sequence represents a transitional type between the submediterranean-subcontinental and the continental types. In addition, southern slopes support higher biodiversity and are more patchy than northern ones.

Lengyel et al. (2012) Applied Vegetation Science

Szabolcs Lengyel, Katalin Varga, Beatrix Kosztyi, László Lontay, Eszter Déri, Péter Török, Béla Tóthmérész (2012): Grassland restoration to conserve landscape-level biodiversity: a synthesis of early results from a large-scale project. Applied Vegetation Science 15(2): 264-276.



Abstract
Question: European landscapes have long been influenced by intensifying use by humans. Although habitat restoration can reverse this process, it is often limited in scope by socioeconomic constraints. Here we present a grassland restoration project that is exceptional in spatial scale in Europe.
Location: A total area of 760 ha of arable land was restored in the Egyek-Pusztakócs unit (50 km2) of Hortobágy National Park, east Hungary, between 2005 and 2008.

Methods: Restoration targeted alkali steppes and loess grasslands by sowing seeds of either two (alkali) or three (loess) foundation grass species. In 2009, we surveyed the vegetation in restored and target grasslands and quantified the factors influencing restoration success in a space-for-time substitution design.
Results: We recorded 100 species of flowering plants, of which 37 species were non-weed, ‘target’ species. Annual weeds dominated 1-yr-old fields but had decreased dramatically by the third year due to a developing perennial grass cover. Former alfalfa fields had proportionally fewer weeds than former cereal and sunflower fields. The diversity of common species and the cover of target species increased from 1- to 4-yr-old restored fields. Alkali-restored fields had more heterogeneous vegetation and more species than loess-restored fields. Distance to the target vegetation did not directly affect vegetation variables. There was significant spatial variability in vegetation development, possibly suggesting several local pathways of succession.
Conclusions: Grassland restoration was generally successful in accelerating secondary succession towards alkali steppes and loess grasslands. However, further management is necessary to counter the homogenizing effects of litter accumulation, to reduce perennial weeds and to enhance the colonization of target species. Our project provides useful practical insights into grassland restoration and in applying restoration at a number of sites within a larger area to conserve biodiversity at the landscape scale.


Keywords
Conservation; Habitat diversity; Landscape ecology; Management; Mosaic habitat structure; Pannonic alkali steppe; Pannonic loess steppic grassland; Restoration success; Succession

Török et al. (2012) Journal for Nature Conservation

Péter Török, Tamás Miglécz, Orsolya Valkó, András Kelemen, Balázs Deák, Szabolcs Lengyel, Béla Tóthmérész (2012): Recovery of native grass biodiversity by sowing on former croplands: Is weed suppression a feasible goal for grassland restoration? Journal for Nature Conservation 20(1): 41-48.


Abstract
Grassland restoration on former croplands offers good opportunity to mitigate the loss of grassland biodiversity. Weed suppression can be another benefit, which becomes increasingly important because of the high recent rate of abandonment of arable lands in Central and Eastern Europe. Our aim was to evaluate the usefulness of sowing two low-diversity seed mixtures followed by annual mowing, a frequently used restoration technique, in weed suppression. We found that rapidly forming cover of sown grasses effectively suppressed short-lived weeds and their germination except in the first year. The detected dense seed bank of short-lived weeds points out the possibility and threat of later weed infestation. In the short run perennial weeds cannot be suppressed easily by sowing and annual mowing. We found that the effectiveness of seed sowing followed by mowing in weed suppression can be different on sites with different history or seed mixture. Rapidly establishing perennial weeds, such as Agropyron species were only detected in former alfalfa fields; Cirsium arvense was found in former cereal and sunflower fields but not in former alfalfa fields. We found that the rate of weed suppression and success was influenced by the seed mixtures used. In several alkali restorations the high proportion of perennial weeds was detected in year 3. In loess restorations, much lower scores were typical. This was likely caused by the different seed mixture used. The loess seed mixture contained seeds of a clonally spreading tall-grass, Bromus inermis, which could compete more effectively with clonally spreading weeds, than could short grass species with or without tussock forming. Our findings indicate that post-restoration management require carefully designed actions that are fine-tuned addressing specific threats at the site level.

Keywords
Seed sowing; Weed suppression; Plant trait; Succession; Establishment success; Cropland

Valkó et al. (2012) Flora

Orsolya Valkó, Péter Török, Gábor Matus, Béla Tóthmérész (2012): Is regular mowing the most appropriate and cost-effective management maintaining diversity and biomass of target forbs in mountain hay meadows? Flora 207(4): 303-309.


Abstract
Conservation of grassland biodiversity is a key issue in the EU agro-biodiversity policy. We assessed the effects of yearly mowing on target forb biomass in years with contrasting precipitation (2006–2007) in mountain fen and dry-mesophilous hay meadows in NE-Hungary. We hypothesised: (i) Species richness and biomass of target forbs is higher in mown than in abandoned stands. (ii) Mowing has more an effect on the biomass of target forbs, graminoids and litter than precipitation.

Mowing increased the species richness of forbs and target forbs. The biomass of forbs and target forbs was not affected by mowing because of the specific responses of certain forbs. The majority of target species were supported, but tall forbs (Succisa pratensis; Lathyrus pratensis) were suppressed by mowing. Precipitation affected only the amount of litter in dry-mesophilous meadows and forb biomass in fen meadows. In the dry year, the biomass of target forbs decreased but the proportion of the species did not change. Our results showed that mowing is necessary to maintain overall plant biodiversity in hay meadows by removal of graminoid biomass and litter, but not all target forbs were favoured by regular yearly mowing. Decreased mowing frequency (mowing in every second or third year) on the entire meadow or temporarily changing mosaics of mown and unmown stripes might be the most suitable management option for maintaining the highest biodiversity of forbs.

Keywords
Target species; Phytomass; Grassland biodiversity; Mosaic management; Cost-effectiveness; Grassland restoration

Török et al. (2012) Ecological Engineering

Péter Török, Tamás Miglécz, Orsolya Valkó, András Kelemen, Katalin Tóth, Szabolcs Lengyel, Béla Tóthmérész (2012): Fast restoration of grassland vegetation by a combination of seed mixture sowing and low-diversity hay transfer. Ecological Engineering 44: 133-138.

Abstract

Technical reclamation of grasslands is a powerful tool for conserving biodiversity in fragmented landscapes. Plant material transfer and sowing seeds of local provenance are used most frequently to recover grassland vegetation in former croplands. The joint application of these methods is rarely used, although it has the potential to gain a predictable and directed vegetation development with effective early weed suppression. We studied the effectiveness of combining low diversity seed sowing and hay-transfer in weed suppression and recovery of perennial grassland vegetation in Hortobágy Puszta, Central-Europe, by testing the following hypotheses: (i) lower weed cover and biomass is expected in vegetation recovered by the joint method of sowing and hay transfer than by seed sowing only. (ii) With sowing and additional hay transfer a higher rate of establishment of Festuca species is expected than with sowing only. Our results supported both hypotheses. We found that the additional application of hay significantly accelerated the development of perennial grassland vegetation and provided a higher weed suppression rate in the first year and onwards in most plots than seed sowing only. A higher establishment rate was detected both in the cover and the biomass of perennial grasses including Festuca species in all plots with hay addition than with sowing only. Our results suggest that a combination of hay transfer and low diversity sowing may provide a cost-effective alternative to the more costly high-density sowing and if proper sources for high-diversity hay are available, it may replace high-diversity seed mixtures.

Keywords

Grassland restoration; Festuca; Biomass; Litter; Weeds; Mulch; Species richness

Molnár V. & Sramkó (2012) Biologia

Attila Molnár V. & Gábor Sramkó (2012): Epipactis albensis (Orchidaceae): a new species in the flora of Romania. Biologia 67(5): 883-888.

Abstract

A small population of Epipactis albensis Nováková & Rydlo, a species previously unknown in the flora of Romania, was found in Gorge Turda (Cheile Turzii, county Cluj) in 2011. The occurrence is currently the easternmost known population of this strictly autogamous species originally described from the Czech Republic, and recently known only from five other Central-European countries. Morphological features, habitat preference, soil reaction, currently known distribution and biological characteristics of the plant are presented.

Keywords

Epipactis albensis, autogamous species, distribution, floristics, mapping, Romania

Molnár V. et al. (2012) Journal of Ecology

Attila Molnár V, Jácint Tökölyi, Zsolt Végvári, Gábor Sramkó, József Sulyok, Zoltán Barta (2012): Pollination mode predicts phenological response to climate change in terrestrial orchids: a case study from central Europe. Journal of Ecology 100(5): 1141-1152.

PDF a Greenfo.hu oldalról

Summary

1. Herbarium collections contain long-term data for a wide range of taxa and provide unique opportunities to evaluate the importance of life-history components in driving species-specific responses to climate change. In this paper, we analyse the relationships between change in flowering dates and life-history traits within a phylogenetic framework. The study is based on an extensive data set of herbarium specimens of orchids collected in Hungary between 1837 and 2009, supplemented by recent field observations (1980–2011).
2. Of the 39 taxa investigated, 31 (79%) showed apparent advancement in mean flowering time. Among these, advancement was statistically significant in nine taxa. The rest (eight taxa) showed non-significant delays in flowering. Averaging across all taxa, flowering time advanced by 3 days (3.8% of flowering period) during the last 50 years compared with the period before 1960. In taxa showing significant advancement, flowering times advanced by 7.7 days (8.6% of the flowering period). The most extreme advancement was 13.9 days.
3. Multivariate models were used to evaluate ways in which life history may affect phenological responses to climate change. Pollination mode (i.e. deceptive vs. rewarding vs. autogamous), life span (i.e. short-lived vs. long-lived), biogeographical distribution type (i.e. Mediterranean vs. non-Mediterranean) and flowering time (i.e. mean date of blooming) emerged as important factors that influence changes in flowering through time. Phylogenetic relatedness did not predict phenological response. The strongest response was observed in orchids that flower relatively early in spring, exhibit an autogamous or deceptive pollination mechanism, have a long life span and possess a Mediterranean centre of distribution.
4. Synthesis. Our investigation demonstrates that the majority of Hungarian orchids have shifted their yearly mean flowering to earlier dates during the past 50 years. Certain life-history traits, but not phylogenetic relatedness, were found to be important in predicting climatic responsiveness in European terrestrial orchids.

Keywords
biological collections; flowering time; global change; herbarium specimens; life history; life span;  Orchidaceae; phenological shift; phylogenetic control; plant–climate interactions; pollinator

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Az Ökológus Tea előadássorozat tavaly indult Oborny Beáta szervezésével és néhány diáktársam segítségével az ELTE-n. Az első évben igen tartalmas előadásokat hallottunk, és legalább ilyen gondolatébresztőek voltak az előadások utáni viták, diskurzusok. A tavalyi tapasztalatok alapján úgy vélem, jócskán vannak magas színvonalú kutatások Magyarországon (ebben megerősít a nem rég lezajlott 9. Magyar Ökológus Kongresszus is), de eddig a születő eredmények itthon mégsem kaptak kellő publicitást. Ennek egy oka lehet talán, hogy a legfontosabb kutatási eredményeinket leginkább nemzetközi, referált, angol nyelvű folyóiratokban jelentetjük meg (előbb vagy utóbb), ahhoz azonban túl sok folyóirat létezik, hogy a többségünk az érdeklődési területén kívül is böngésszen a közlemények között. Ahhoz, hogy rendszeresen értesüljünk arról, milyen kutatások folynak, milyen eredmények születnek a magyar ökológiában, hasznos lenne egy olyan "hírcentrum", amely tudósít a frissen megjelenő cikkekről. Ezt szeretnénk megvalósítani a most induló Ökológus Tea Blog segítségével.

A blog tulajdonképpen szakirodalmi figyelőként fog működni, magyar szerzők által írt, referált (impakt faktorral rendelkező) folyóiratban megjelent cikkek hivatkozásai és absztraktjai jelennek majd meg rajta. A blogot olvasók viszonylag frissen értesülhetnek a legfontosabb hazai, ökológiai kutatási eredményekről, ami már önmagában érdekes lehet, de reméljük, hogy ez új tudományos együttműködéseket is inspirálhat a különböző kutatási területek között. Szintén hasznos forrás lehet kutatási témát vagy témavezetőt kereső hallgatók számára, akik innen tájékozódhatnak a magyar tudományos műhelyek eredményeiről.

Az összefoglalók feltöltését a 2012-ben megjelent cikkekkel kezdjük. Az általunk elérhető és rendszeresen figyelt folyóiratokat igyekszünk magunk végigböngészni a ma (szeptember 19-én) aktuális számoktól kezdődően, és kikeresni a magyar szerzők műveit. Biztosan lesz azonban olyan cikk, amit nem találunk meg, ezért kérünk minden olyan magyar szerzőt (határon innen és túl), akinek a 2012. évtől van referált folyóiratban megjelent, ökológiai témájú közleménye, hogy küldje el a cikk hivatkozását az okologustea.blog [ kukac ] gmail.com címre. A beküldött cikkek között olyanok is lehetnek, amelyek a 2012. év korábbi számaiban jelentek meg, de az ilyen számokban keresni már nem fogunk. A referált folyóiratokra való szűkítés miatt nem szeretnénk az "impakt-sznobizmus" bűnébe esni. Valamilyen módon azonban húznunk kellett egy határt, hogy saját munkánk elvégezhető mennyiségű legyen, és - mivel a munkát diákok végzik - egyszerűsítsük a döntést.

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Lengyel Attila

(blogszerkesztő, ELTE TTK PhD hallgató; honlapom itt)