Plant communities of trampled habitats in North Korea

Abstract. A syntaxonomic study of trampled plant communities in North Korea is presented. Analytic and synthetic methods of the Braun-Blanquet approach together with a numeric-syntaxonomical analysis (cluster analysis and principal coordinate analysis ordination) were employed. With the exception of the Bryo-Saginetum japonicae, all the associations, such as the Artemisio asiaticae-Plantaginetum asiaticae, Plantagini depressae-Polygonetum avicularis, Polygono avicularis-Potentilletum costatae, Eragrostio multicaulis-Plantaginetum depressae, Euphorbio maculatae-Centipedetum minimae, Digitario pectiniformis-Eleusinetum indicae and Setario viridis-Chlorisetum virgatae, are described for the first time. Some communities also include a number of subassociations. Trampled communities are found along edges of paths and in cracks among paving stones. Soils vary from loamy to sandy and skeletal. A phenomenon of seasonality in expression of ruderal communities was observed in North Korea. It is assumed that this seasonality is controlled by pattern of precipitation showing distinct climatic seasons (e.g. pre-monsoon and post-monsoon periods). The ruderal vegetation seasonality is supposed to become more pronounced towards tropical regions. Several mesophilous or slightly hygrophilous European species occur frequently in North Korean trampled communities including Chenopodium glaucum, C. ficifolium and Potentilla supina. Their occurrence in trampled habitats is hypothesized as being related to high air humidity and associated wet climate.     

The desert vegetation of El Pinacate,Sonora, Mexico

The Pinacate region is part of the Gran Desierto, one of the driest deserts in North America. The presence-absence of perennial plant species, together with soil and landform characteristics, were registered in 110 sampling sites within this region. A classification and ordination of plant communities showed soil and landform units to be good predictors of plant variation. Plant distribution and species richness were also strongly related to altitude and rockiness. A Generalised Linear Model was used to fit the response curves of individual species.The environmental factors related with plant distribution are indicators of the water regime within a given site. Plant communities repeat along topographic gradients the large-scale biogeographic variation of the Sonoran Desert. Microphyllous shrubs colonise the drier bajada slopes, while more diverse communities, dominated by cacti and drought-deciduous trees, grow on the wetter pediments and in pockets within rocky soils.     

Classification and ordination in the Indian Peaks area,Colorado Rocky Mountains

Summary A mid-latitude, Northern Hemisphere alpine vegetation in the Colorado Rocky Mountains was suitable for analysis by syntaxonemie and numerical methods, which interpreted the Braun-Bianquet association data, distributed by habitat and vegetation dominance types, correspondingly. Classification and ordination yielded complementary, interpretable results, which combined were more informative than results of either technique alone. Syntaxonomic results can faeilitate the interpretation of numerical results; the syntaxonomic relationships can be clarified by the results of numerical analysis.Alliances and orders of the Braun-Blanquet hierarchy, and their diagnostic taxa groups were derived by numerical methods from an association/taxa matrix. On the basis of this matrix, numerical methods demonstrated some of the environmental gradient complexes controlling the compositional variation. The compositional distinctiveness and uniformity of orders and alliances parallel environmental distictiveness and uniformity.The following attributes of the sampled vegetation and environment were probably responsible for the successful combination of syntaxonomic and numerical results: 1. The sampled area as a geographically limited universe, characterized by relative environmental, biotic, and historical distinctiveness and uniformity, 2. The wide range, high diversity, and clear denfinition of habitat and vegetation dominance types. Because it effectively summarizes and simplifies field data, syntaxonomy can play an important role in building local vegetatio models.Most of the figures in this paper are from a book version of a University of Colorado, Department of Environmental, Population, and Organismic Biology, Ph. D. thesis which was produced at the Institute of Arctic and Alpine Research. I would like to thank Dr. P.J. Webber, the thesis advisor, for his support, for suggesting the numerical methods, and for computer programs which were written by W.F. Reid. Vicki Dow, Marilyn Joel, and Karen Sproul drafted the majority of figures. I am grateful to Gwen Archer for editorial help.     

The vegetation of a New Zealand dune slack

The vegetation of a dune slack at Mason Bay, Stewart Island, New Zealand was found to comprise a mosaic of communities. Although the broad vegetational patterns could be correlated with the depth of the water table, the patterns were far from simple. Species diversity over the whole slack was lower than values reported from European dune slacks; even the most diverse communities did not reach European mean values.For nomenclature see Wilson in press. Vascular plants of Stewart Island. D.S.I.R., Wellington, New Zealand; Sainsbury (1955). A handbook of the New Zealand mosses. N.Z. R. Soc. 5: 1–490 & Hamlin (1972). Hepaticae of New Zealand, Dominion Museum, Wellington.     

Correlation between stand structure and ground vegetation: an analytical approach

The effect of stand structure on the diversity of the forest's ground vegetation was examined based on data on permanent sample plots collected in the northern parts of North-Carelia, eastern Finland. Different ordination methods (DCA, GNMDS, LNMDS, and HMDS) were used together with the TWINSPAN classification method. The aim was to construct a basis for classifying forests with respect to the biodiversity of the forest vegetation. Fertility and stand age showed the strongest correlation with the variation in ground vegetation. Other important factors were basal area, tree species composition, and crown cover. These variables were important in the division of the sample plots into different classes. According to the diversity indices, species diversity was at its highest in young stands on fertile forest sites. As a result, twenty-one different classes were formed based on the relative abundance of understorey species. The variables with the highest correlation were used to describe the stand structure in these classes.     

Numerical studies of compositional gradients in oreophilous vegetation (northern Apennines,Italy)

Summary A numerical study of a set of phytosociological data from oreophilous vegetation in the Apennines (Italy) has been performed. Ranking, classification and ordination methods have been used. The advantages of the joint use of the different methods is diseussed. The results confirm a compositional gradient related to degradation due to grazing, and another, related to base-richness in the soil. Compositional variation does not appear strongly disjointed.Nomenclature follows Zangheri (1976)This work was supported by a grant from the Italian CNR, Pfoject Environment Quality. We wish to thank Professor L. Orlóci for discussions and facllities, and Drs. D. Ubaldi and C. Ferrari for participation in the fieldwork.     

Two centuries of vegetation succession in an inland sand dune area,central Netherlands

Questions: (a) What are the rates and directions of vegetation succession in an inland sand‐dune system? (b) What are the differences in successional trajectories in different relief types? and (c) Is it possible to preserve the last areas of still active dunes and under what circumstances? Location: The study sites were located in the northern part of the Veluwe Region, central Netherlands; longitude 5°44′ E, latitude 52°20′ N, altitude 9 to 24 m a.s.l. Methods: Vegetation and relief mapping was conducted in three permanent plots, 200 m × 200 m in size, in 1988 and 2003. Phytosociological relevés (2400) were recorded in each 10 m × 10 m subplots. Age of woody species was determined by wood coring. Geographic Information System, ordination analyses, and TWINSPAN were used for data exploration and elaboration. Results: A total of 70 vascular plants and 19 bryophytes were recorded over successional stages spanning approximately190 years. The following dominant species formed the sequence of successional stages, but not all participated in all relief types: Ammophila arenaria, Festuca arenaria, Corynephorus canescens, Festuca ovina and Agrostis capillaris, and pine forest dominated in its herb layer at first by Deschampsia flexuosa and later by either Empetrum nigrum, Vaccinium myrtillus or Vaccinium vitis‐idaea. Conclusions: The successional trajectory is basically unidirectional for more than 100 years; no clear multiple successional pathways were observed, as is frequent in coastal dunes. Successional divergence was observed after approximately 130 years in the composition of the herb layer in the closed pine forest. The obvious vegetation heterogeneity in the still active sand‐blown area is related to differences in timing of vegetation establishment on particular relief types, thus the succession exhibits a terrain‐dependent asynchronous character. We conclude that the last patches of still‐active sand dunes can be preserved only by repeated strong artificial disturbances.     

Variation in Greek phrygana vegetation in relation to soil and climate

Abstract. Variation in species composition and community structure in nine Greek phrygana (dwarf-shrub) sites was related to soil and climate variables by using Canonical Correspondence Analysis. The distribution of the Greek phrygana communities appeared to be related to soil rather than to climate. It is postulated that human action has eliminated the original variability related to climate factors in western Greek ecosystems; as a result, phrygana communities in this part of Greece are the result of human impact.     

Size distributions and dispersions along a 485-year chronosequence for sand dune vegetation

Using a sand dune chronosequence that spans 485 years of primary succession, we collected nearest-neighbor vegetation data to test two predictions associated with the traditional "size-advantage" hypothesis for plant competitive ability: (1) the relative representation of larger species should increase in later stages of succession; and (2) resident species that are near neighbors should, over successional time, become more similar in plant body size and/or seed size than expected by random assembly. The first prediction was supported over the time period between mid to later succession, but the second prediction was not; that is, there was no temporal pattern across the chronosequence indicating that either larger resident species, or larger seeded resident species, increasingly exclude smaller ones from local neighborhoods over time. Rather, neighboring species were generally more different from each other in seed sizes than expected by random assembly. As larger species accumulate over time, some relatively small species are lost from later stages of succession, but species size distributions nevertheless remain strongly right-skewed-even in late succession-and species of disparate sizes are just as likely as in early succession to coexist as immediate neighbors. This local-scale coexistence of disparate sized neighbors might be accounted for-as in traditional interpretations-in terms of species differences in "physical-space-niches" (e.g., involving different rooting depths), combined with possible facilitation effects. We propose, however, that this coexistence may also occur because competitive ability involves more than just a size advantage, with traits associated with survival (tolerance of intense competition) and fecundity (offspring production despite intense competition) being at least equally important.     

Arbuscular mycorrhizae in a tropical sand dune ecosystem on the Gulf of Mexico

 Root samples of 37 species distributed on the beach and along a successional gradient (from mobile to stabilized areas) in a tropical sand dune system on the Gulf of Mexico showed that 97% of the species were mycorrhizal. The mycorrhizal inoculum potential of the sand from several dune areas was compared using two different bioassays. Firstly, the field rate of colonization by arbuscular mycorrhizal fungi of Chamaecrista chamaecristoides seedlings transplanted to random plots in the foredunes and in the mobile area was measured. The seedlings were harvested at intervals during 3 weeks to record mycorrhizal structures. In the mobile area, no mycorrhizal colonization was observed during the experiment. In the foredunes, hyphae and external mycelium were present in 40% of the seedlings as early as 8 days after transplanting. After 15 days, arbuscules and vesicles were observed in 60 and 20% of the seedlings, respectively, and after 21 days, 100, 46 and 20% of the seedlings showed hyphae, arbuscules and vesicles, respectively. Secondly, maize seedlings were transplanted to pots previously filled with sand from the foredunes, mobile dunes, grassland and a Dyphisa robinoides shrub area. After 1 month, the lowest mycorrhizal inoculum potential was recorded for the mobile dunes and the highest for the shrub area. As expected, mycorrhizal inoculum potential increased with dune stabilization. Accepted: 17 July 1996     

Coastal lowland vegetation of eastern Saudi Arabia

This study assesses the plant communities and environmental factors that govern species richness and distribution in the coastal lowlands of eastern Saudi Arabia using TWINSPAN, DCA and regression analyses. Thirty-four vegetation groups were identified, some of these occur in only one habitat: Juncus rigidus and Aeluropus lagopoides-Phragmites australis in the high saline flats, Plantago boissieri-Savignya parviflora, Panicum turgidum-Plantago boissieri-Moltkiopsis ciliata and Panicum turgidum-Haloxylon salicornicum in the non-saline flats, and Bassia eriophora-Launaea mucronata in the depressions between dunes. Some other groups are represented in at least four out of six studied habitats: Zygophyllum qatarense-Launaea capitata-Plantago boissieri, Zygophyllum qatarense-Plantago boissieri and Haloxylon salicornicum-Zygophyllum qatarense. Among 20 examined soil and community variables, regression analysis indicates that only six are influential in the stand ordination process (K, lime, sulphates, pH, plant cover and species richness). Some human impacts (e.g. grazing and cutting intensities) also play an important role. The nature of soil surface and salinity are the main factors that affect the species richness. This revised version was published online in November 2006 with corrections to the Cover Date.     

Home Garden Production and Energetic Sustainability in Calakmul,Campeche, Mexico

Energy flows were studied for the 2002–2003 agricultural cycle in four households for which agriculture is part of a diversified survival strategy and four that practice agriculture as a business. Home garden inputs and outputs were measured monthly. Quantified inputs were: household labour, household agro-system production, and purchased external renewable and non-renewable energy. Outputs measured were: sales, family and animal foods. While both strategies had similar indicators in biomass and energy production, vegetable richness, and soil quality, household garden function and sustainability differed between subsistence and commercial householders. Subsistence gardens complemented family diet and contributed to household system resiliency. They relied heavily on renewable energy sources from within their agro-system. Gardens in commercial households reduced fruit tree area and increased animal husbandry for the market. They depended more on purchased non-renewable energy sources and were less sustainable and much less energy efficient than traditional gardens.

Effects of grass-encroachment on vegetation and soil in Dutch dry dune grasslands

The encroachment of tall grass species in open dune vegetation, as observed in the Dutch dry dune area, is considered unfavourable for nature conservation. The effects of grass-encroachment on the vegetation and the availability of light and its relation to nutrients were investigated through a comparative study of grass-dominated and open dune grassland plots at ten locations along the Dutch coast.Grass-dominated plots have a low species diversity and number of species, especially of mosses and lichens. This is associated with a high biomass and a low availability of light at soil surface. In addition, nutrient availability seems to be important. Root biomass and the amounts of both ectorganic and endorganic matter are significantly higher in grass-dominated plots, which may account for the higher nutrient uptake in the vegetation.It is likely that a grass-dominated system can maintain and consolidate itself because of the better competition for light and nutrients. The relevance of these results for restoration management is briefly discussed.     

Short-term responses of rehabilitating coastal dune forest ground vegetation to livestock grazing

We investigated the responses of the ground vegetation in a 17‐year‐old coastal dune forest plant community to four levels of experimentally applied livestock grazing (three grazing levels and one ungrazed control) from May 1994 to March 1996. The effects of grazing were apparently subordinate to site‐specific intrinsic vegetation change and there were some indications that rainfall interacted with grazing level. Grazing had some apparent but no significant effects on plant species composition, significantly affected plant species richness over time, and significantly increased the range of species richness and vegetation cover values as well as the relative abundance and numbers of plant species with erect growth forms. Vegetation cover changed significantly over time, independently of grazing. Our results point to two important, easily measured mechanisms for the conservation management of coastal dune forests – the interaction of disturbance type with plant growth form and the increase of variation in community structural variables under disturbance. These mechanisms, although they potentially have wide application and predictive power, have not been studied adequately.     

Influences of transformation of cover values on classification and ordination of lake vegetation

Summary Numerical ordination (Program ORDINA) and classification (Program TABORD) have been applied to vegetation data from a lake in south Sweden.Full percentage values and different transformations of the estimated percented cover scale have been tested on relevés with nymphaeids (+ elodeids) and on relevés containing obly helophytes. The used scales have been: percentage (P), Hult-Sernander-Du Rietz (HSD), Log (%+1) (LP), 1+ log% (L), 100+ % (HP) and Presence/Absence (P/A). The main aim has been to find if there is an optimal transformation regarding both quantitative and qualitative information in vegetation data.In the classification of helophytes a dataset with 87 relevés and 20 species have been used applying P-and L-scales and P/A. The similarity between the different scales has been compared in relation to common relevés between every two corresponding clusters. L and P/A give very similar results, more similar than L and P or PA and P. It is also interesting that the result with P-scale is more similar to L than to P/A. The P-scale neglects with the species with a low cover value, whilst the L-scale takes notice of both quantity and quality.In the classification of 90 nymphaeid relevés containing only 6 species P, HSD, L, HP and P/A were applied. The L-scale (and partly PH-scale) gave a result similar to the most quantitative P-and HSD-scales. P/A-values gave a very deviating result. In the ordination of helophytes only 38 relevés with 18 species, taken along a transcect, were used and P, P/A and 4 different transformations were applied. The similarity between order of relevés in the graphs and real order of relevés along the transect was used as an objective test of the effectiveness of the scale applied. The P-scale gave a bad result, whilst P/A gave the best result. The intermediate scales L and HP gave acceptable results.In the ordination of nymphaeids (+ elodeids) 90 relevés, where only pattern was studied, the L-scale gave the best result most similar to P-and HSD, but applying the two extremes, P-scale and P/A, resulted in large reduction of information.In the submitted ordinations and classifications the applied L-scale (and HP-scale) always gave ecologically interpretable results, but the extreme transformation were less reliable.This work has been supported by grants from the University of Lund, for which I am duty grateful.Nomenclature follows Lid (1974).I am grateful to Professor Nils Malmer, head of the Department of Plant Ecology, Lund, Sweden, Dr. Eddy van der Maarel, University of Nijmegen, Holland, and my colleague Fil. Kand. Stefan Persson for valuable advice and discussions. I also thank my wife Fil. Kand. Eva Waldemarsson Jensén, Institute of Ecological Botany, Uppsala, for valuable discussions, Mr. Tommy Olsson for valuable technical advice, Dr. R.S. Clymo for advice with DIVINF and PCA and correction of the language, Mrs. Mimmi Varga for drawing the figures and Mrs. Brita Billstein for typewriting the text and the tables.