A recent floristic and environmental survey was undertaken on the roadside verges along the main highway between El Arish and Rafah (31° 10'N, 33° 48'E and 31° 17'N, 34° 15'E) that extend for about 45 km on the northeastern Mediterranean coast of Sinai (Egypt). 63 stands were studied at 700-m intervals to represent the variation of vegetation, and to compile the floristic composition of the study area. Four main landform zones were distinguished (from the seashore inwards) and run parallel to the roadway: (A) coastal plain, (B) saline depressions, (C) sand plains and (D) sand dunes. There is a gradual increase in the total number of recorded species in the recognized landform units. Application of TWINSPAN analysis yielded 18 vegetation groups (VG) that comprised 7 main vegetation types (VT). These vegetation types were (I) Artemisia monosperma in the sand dunes, (II) Artemisia monosperma-Echinops spinosus in the sand plains, coastal plain and sand dunes, (III) Cyperus capitatus-Ammophila arenaria in the sand dunes, (IV) Ammophila arenaria-Pancratium maritimum in the coastal plain, (V) Zygophyllum album, (VI) Arthrocnemum macrostachyum and (VII) Arthrocnemum macrostachyum-Zygophyllum album in the saline depressions. Ordination techniques of Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to examine the relationship between the roadside vegetation and the 8 studied environmental variables: total soluble salts (TSS), pH, calcium carbonate (CaCO_), sand, fine fractions (silt and clay), distance from the seashore (DFS), landform units (LF) and altitude (Alt). Both ordination techniques indicated that soil salinity, calcareous sediments, soil texture, landform, altitude and distance from seashore were the most important factors for the distribution of the vegetation pattern along the road verges in the study area. These gradients were related closely to the first three CCA axes, and accounted for 72.4% of the species relationship among the stands. Low species richness in the vegetation types of the coastal plain and saline depressions may be related to their high soil salinity, while the high species diversity and the highest share of alien weeds of vegetation types characterized the sand dunes may be related to the high disturbance of their substrates as a result of agriculture practising, farming processes and other excessive human disturbances.
We investigated how cluster analysis and diversity-ordering can be used for the classification of geographically and historically distinct plant and insect communities. The study sites include fens and Brachypodium pinnatum dominated grasslands. The stands of the fen vegetation type could be arranged into similar groups by cluster analysis, principal component analysis and diversity ordering techniques. In the case of the B. pinnatum dominated grasslands of diverse development, however, no groups could be differentiated on the basis of either diversity ordering or ordination. Of the various cluster analyses, the result of global optimisation was similar to those of PCA ordination and diversity ordering techniques.
Authors:J. T. Kundrát, Zs. Balogh, S. Harangi, B. Tóthmérész, and E. Simon
The contamination level of oxbows depends on both natural and anthropogenic effects. The aim of our study was to identify those abiotic and biotic factors that determine the contamination level of oxbows. The effect of anthropogenic activities, seasonality, and vegetation types was studied on the contamination level of surface water of oxbows. The following chemical variables were measured: suspended solid, ammonium, nitrate, chlorophyll-a, Al, Ba, Fe, Mn, Pb, Sr and Zn from eight oxbows from 2013 summer to 2014 autumn in the Upper Tisza region in Eastern Hungary. Three of the studied oxbows were protected, four oxbows were used for fishing and one oxbow was contaminated with wastewater. Our findings revealed that anthropogenic activities had remarkable effect on the contamination level of oxbows. Seasonality also influenced the contamination level, except the concentration of suspended solid, chlorophyll-a and manganese. Significant differences were found among vegetation types for the concentration of suspended solids, aluminium, iron, manganese and lead. The high level of iron concentration was not explained by the anthropogenic activities, suggesting that the quality of oxbows depends on both natural and anthropogenic effects.
The present study was carried out at a dune slack meadow near Mórahalom town in the Southern part of the Great Hungarian Plain. The area of the grassland is approximately 840,000 m
. The vegetation is mosaic-like in accordance with the variable microrelief and water content. The lower part of the grassland consists of various types of saltmarshes and wet meadows and at the upper microrelief, Pannonic sand steppe patches occur. True bug assemblages were sampled at 16 patches using 5×50 sweeps at each sampling site. The sampling was repeated three times in both 2007 and 2008. The area, the perimeter, the shape index of the sampled patches as well as the diversity of the surrounding patches were assessed as “landscape parameters”. The plant species number and diversity of the sampled patches were estimated from the data of 5×5 m coenological quadrats. Altogether 66,087 adult individuals belonging to 153 species were collected. The ordination methods showed that the true bug assemblages of the sampling patches differ from each other in accordance with the vegetation type. These assemblages differed in their species composition and diversity as well as in their assemblage structure. The results suggested that the vegetation type based on plant species composition determined the true bug assemblages.
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:A. Huertas Herrera, M. V. Lencinas, and G. Martínez Pastur
The comprehensive assessment of environmental gradients influencing species assemblages is important for implementing new conservation strategies under climate change. This study aims to determine the multi-scale effect of altitudinal and longitudinal gradients as drivers of richness and plant community assembly in mountain landscapes of Isla de los Estados (Argentina) to identify areas with greater conservation value in Southern Patagonia. We chose three fjords across the island that extends from West to East and we categorized landscapes into four ecosystem types according to their vegetation type (forests and open-lands) and elevation (lower lands, 0-100 m.a.s.l. and upper lands, 300-400 m.a.s.l.). Forest structure, soil cover (woody debris, rocky outcrop and bare soil) and vegetation cover (vascular and non-vascular), including richness and growthforms (trees, shrubs, prostrate and erect herbs, tussock and rhizomatous grasses, ferns and inferior plants) were measured in 60 sampling areas (3 fjords × 2 vegetation types × 2 elevations × 5 replicates). ANOVAs and multivariate methods were used to analyse heterogeneity in forest structure, plant richness, and life-form. In addition, species richness and the Simpson’s diversity index were calculated to understand plant assembly at multiple-scales (α, β and γ). Our results showed that environmental gradients (altitudinal and longitudinal) are more important drivers of change of ecosystem type than forest spatial structure. Furthermore, forest structure significantly varied with altitudinal and longitudinal gradients affecting most of the studied variables. A greater similarity (in richness and cover) between open-lands of lower and higher elevations was detected, as well as between forests. Fjords showed a West-East gradient, where the western and center fjords were more closely related to each other than to the eastern fjord. A multi-scale diversity approach may play central role in improving our understanding the main environmental drivers of richness and plant community assembly in these forests, both theoretical and empirical, and may be used to identify the spatial scale at which ecosystem types have greater conservation value. This study indicates that for southern forest conservation at regional level, efforts must cover all environmental gradients, including the different vegetation types to assure ful conservation of all the species assemblages.
Govind Wild Life Sanctuary in the Western Himalayas with its diverse vegetation types provides excellent habitats and microclimates for a lush growth of bryophytes. During investigations on the bryophytes of this region Plagiothecium euryphyllum (Cardot et Thér.) Z. Iwats. and P. cavifolium (Brid.) Z. Iwats. have been identified for the first time from India. P. euryphyllum is characterised by bright green to yellowish green plants, irregularly branched, complanate. Central strand developed. Leaves erectopatent, imbricate, ovate oblong, margin entire, acute to acuminate at apex, costa two forked, decurrent with hyaline, rectangular cells. Seta reddish, capsule erect to inclined, while plants of P. cavifolium are yellowish green, glossy, prostrate, irregularly branched, branches julaceous. Leaves appressed to stem, closely imbricate, erectopatent, ovate lanceolate, symmetrical, margin minutely dentate at apex, cells at alar region rectangular costa two short. Seta reddish brown, capsule erect, pyriform. A morpho-taxonomic account of above two taxa is provided.
Authors:A. Borhidi, J. Csiky, K. Lájer, and R. Pál
This paper deals with a new
dominated half-ruderal Pannonian weed association. In order to identify this vegetation type, samples were compared with some dry and semidry Central European weed associations of Agropyretalia repentis. The community studied seems to belong to the Artemisio-Agropyrion repentis alliance. Based on results, the
dominated dry half-ruderal sand grass stands are classified in the frame of a new association under the name of
Gypsophilo paniculatae-Agropyretum repentis
. It can be divided into two subassociations, notably a more natural typical one rich in species, replacing disturbed sand grasses →
, and another type containing less species and exposed to much stronger disturbance →
The relationship between plant communities and elevation in the Guandi mountainous area was studied. Data from 89 sampling units, each of 10 m x 20 m size, taken along an elevation gradient were analyzed by TWINSPAN, DECORANA and diversity and evenness indices. The samples were clustered into 23 groups by TWINSPAN, representing 23 vegetation types. The composition and distribution of communities varied greatly along the altitude gradient, suggesting that community diversity is closely related to elevation in the Guandi Mountains. This is due to the change of temperature and water-conditions along the elevation gradient. Species heterogeneity and evenness were significantly correlated with elevation along the entire gradient, but showing first a trend of increases and then decreases, corresponding to the hypothesis of maximum diversity at medium elevation. Species richness varied greatly in the study area, and was not significantly correlated with elevation.
We present a test involving a large number of data-analytical techniques to identify a rigorous numerical classification method optimising on statistically identified faithful species. The test follows a stepwise filtering process involving various numerical-classification tools. Five steps were involved in the testing: (1) evaluation of 322 classification tools using Optim-Class 1; (2) comparison of 20 best performing methods by standardising the various performances across a range of fidelity values using OptimClass 1 and OptimClass 2, to assess the effectiveness of the agglomerative clustering and one divisive technique; (3) calculation and comparison of Uniqueness values and ISAMIC (Indicator Species Analysis Minimising Intermediate Constancies) scores of the resulting classifications; (4) comparison of different classifications by analysing the similarities of the resulting synoptic tables using faithful species, assuming that clusters with similar faithful species represent corresponding vegetation types, and (5) final selection of the single best method based on an expert review of non-geometric internal evaluators, NMDS ordinations and mapped classification solutions. A complex data set, representing many forest vegetation types and consisting of 506 relevés of 20 m × 20 m sampled in the indigenous forests of Mpumalanga Province (South Africa), was tested. Analysis of Uniqueness provided insight into which methods produced classifications that did not share faithful species. The analysis of synoptic table similarity showed that the classification results were at most 88% similar, while in the most divergent case similarity of only 50% was achieved. OptimClass eliminated poorly performing numerical-classification combinations and highlighted the best performing methods. Yet it was unable to reveal the single best performing method unequivocally across the range of fidelity values used. In such cases, we suggest the solution can be sought in relying on involving external data through expert opinion. Ordinal Clustering and TWINSPAN produced the most outlying classification results. Flexible beta clustering (β= −0.25) in combination with Bray-Curtis coefficient, standardised by sample unit totals, produced the most informative result for our data set when using informal expert-defined ecological and biogeographical judgement criteria. We recommend that the performance of a set of methods be tested prior to selecting the final classification approach.