bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of vegetation classification and plant indicators to assess grazing abandonment in Estonian coastal wetlands
Authors: Burnside Niall G. , Joyce Chris B. , Puurmann Elle , Scott Dawn M.
Published: February 2009

Question: What are the effects of grazing abandonment on the vegetation composition of Estonian coastal wetlands?

Location: Vormsi Island and Silma Nature Reserve in western Estonia, Europe.

Methods: Local knowledge and field reconnaissance were used to identify current and historical management levels of wetland sites within the west Estonian study area. Nine study sites, with varying management histories, were selected comprising an area of 287 ha. A total of 198 quadrats were taken from 43 distinct vegetation patches in five of the sites. TWINSPAN analysis was used to identify community type, and a phytosociological key was constructed for character taxa. This vegetation classification was then applied within a GIS‐based context to classify all the study sites, using a ground survey technique and 1:2000 scale air photos.

Results: We identified 11 different brackish coastal wetland community types. Indicator species were defined with community characteristics for the seven main vegetation types readily recognisable in the field. Coastal wet grasslands were most extensive in grazed sites, or sites that had been more intensively grazed, while abandoned sites were largely composed of Phragmites australis stands, tall grassland, and scrub. Site variations based on vegetation composition were significantly correlated with past grazing intensity. Plant community types showed significant edaphic differences, with particularly low soil moisture and high conductivity and pH for open pioneer patches compared to other vegetation types.

Conclusion: Abandonment of traditionally grazed coastal grasslands threatens their characteristic biodiversity. This study found that grazing abandonment reduced the extent of coastal wetland grasslands of particular conservation value. Nevertheless, plant species of conservation interest were found across the sequence of community types described. The study shows that grazing is an important factor influencing coastal wetland plant communities but suggests that vegetation distribution is affected by environmental variables, such as topography.
Habitat engineering under dry conditions: The impact of pikas (Ochotona pallasi) on vegetation and site conditions in southern Mongolian steppes
Authors: Wesche Karsten , Nadrowski Karin , Retzer Vroni
Published: February 2009

Question:Does ecosystem engineering by small mammals have a significant influence on vegetation patterns in the arid steppe vegetation of southern Mongolia?

Location:Gobi Altay Mountains, southern Mongolia.

Methods:We assessed the impact of the small lagomorphOchotona pallasion plant community composition, nutrient levels and biomass production in montane desert steppes. Data were derived from vegetation relevés, harvests of above‐ground standing crop and a bioassay, followed by analyses of soil and plant nutrient contents.

Results:Although the local climate is arid with <150 mm annual precipitation, clear evidence of allogenic ecosystem engineering was found. Plant communities on burrows differed from those on undisturbed steppe in that they contained more species of annuals and dwarf shrubs, and a greater abundance of the important fodder grassAgropyron cristatum. Standing crop and nutrient concentrations were higher for plants growing on burrow soil.In situmeasurements and a pot experiment showed that this effect was related to increased levels of soil nutrients (P, K, N) rather than moisture availability.

Conclusions:The study confirms thatO. pallasipositively influences soil nutrient levels on its burrows, which leads to increased grassland productivity even under dry conditions. Thus,O. pallasidoes not deteriorate site conditions, and the need for presently applied pest control schemes aimed at this species should be reassessed.
Differential effects of emergent Nothofagus dombeyi on growth and basal area of canopy species in an old‐growth temperate rainforest
Authors: Donoso Pablo J. , Lusk Christopher H.
Published: February 2009

Question: Does overyielding of tree species mixtures in vertically stratified forests depend on complementary light use?

Location: Andes of south‐central Chile.

Methods: Basal area data were obtained from 80 circular plots distributed regularly throughout old‐growth stands with an emergent Nothofagus dombeyi tier over a canopy composed mainly of Laureliopsis philippiana and Saxegothaea conspicua. Radial growth was measured from cores obtained from trees at the centre of each plot. The effects of competition on growth were evaluated through a competition index (CI) based on distances to and diameters of the two nearest neighbours.

Results: Overall, basal area of the canopy species was only weakly affected by the number of N. dombeyi per plot, and with basal area of N. dombeyi. However, the two main canopy species responded differently: whereas basal area of S. conspicua was negatively correlated with that of N. dombeyi, that of L. philippiana showed no response. Radial growth of S. conspicua was negatively correlated with CI calculated from canopy trees and more weakly so from emergent N. dombeyi. In contrast, radial growth of L. philippiana was not affected by competition with either canopy or emergent neighbours.

Conclusions: Results indicate that emergent N. dombeyi tend to depress growth and basal area of S. conspicua, but not of the more shade‐tolerant L. philippiana. This supports the proposal that enhancement of wood production in stratified mixtures will be greatest when component species have strongly contrasting light use traits.
Multi‐species interactions in competitive hierarchies: New methods and empirical test
Authors: Perkins T. Alex , Holmes William R. , Weltzin Jake F.
Published: February 2009

Question: Are competitive hierarchies, which are typically based on the results of pair‐wise competition experiments, sensitive to the level of species interaction in the underlying competition experiments?

Location: Controlled greenhouse study using vegetation typical of old‐fields in East Tennessee, USA.

Methods: We extend traditional competitive effect/response methods to incorporate data from competition experiments featuring any level of species interaction (i. e., 2, 3, …, n species interacting simultaneously) and develop an ordinal technique that makes hierarchies more robust to variation in the numerical values of relative yield. We apply these methodological techniques to empirical data from a greenhouse experiment wherein four old‐field plant species were grown in pair‐wise and tri‐wise combination. We also demonstrate how resampling can be used to determine the variability of data and its consequences for development of competitive hierarchies.

Results: Different hierarchies were produced when we used different evaluation methods, different levels of species interaction, and different levels of replication. More acute resampling distributions and wider ranges of target/neighbor scores revealed that higher levels of species interaction lead to more distinct hierarchies.

Conclusions: Hierarchies developed from interactions among subsets of species may inadequately characterize relationships among the full community because of indirect or higher‐order interactions within multi‐species assemblages. Different evaluation methods can yield different hierarchies, and resampling is an effective tool to determine the sensitivity of resultant hierarchies to the level of replication. In sum, our new methodology can be used to control uncertainty in poorly‐replicated experiments.
Multi‐stemmed trees in subtropical coastal dune forest: Survival strategy in response to chronic disturbance
Authors: Nzunda Emmanuel F. , Griffiths Megan E. , Lawes Michael J.
Published: February 2009

Questions: Is multi‐stemming a survival strategy in response to chronic disturbance? Is multi‐stemming under phylogenetic control? What environmental factors are associated with multi‐stemming? When do trees initiate growth of multiple stems? Do multi‐stemmed trees have limited stature?

Location: Subtropical Indian Ocean coastal dune forest at Cape Vidal in the Greater St. Lucia Wetland Park, northeastern South Africa.

Methods: Tree physiognomy and environmental conditions were sampled in 20 transects that were 300 m long and 5 m wide.

Results: 38.9 % of trees were multi‐stemmed, with no correlation between multi‐stemming and taxonomic grouping. The multi‐stemming trait was most associated with stem decumb‐ency and substrate erosion and multi‐stemmed individuals were less common in protected dune slacks. Trees at Cape Vidal appear to facultatively produce multiple stems from an early stage. There was no trade‐off between tree height and stem number.

Conclusions: Coastal winds and the unstable dune substrate are important environmental correlates of multi‐stemming. Both short stature and the high incidence of multi‐stemming are related to the tree‐disturbance interaction. The taxonomically widespread phenotypic plasticity in this trait indicates the importance of multi‐stemming to tree survival even under low levels of disturbance.
Upward shift of alpine plants increases floristic similarity of mountain summits
Authors: Jurasinski Gerald , Kreyling Jürgen
Published: February 2009

Question: Does the upward shift of species and accompanied increase in species richness, induced by climate change, lead to homogenization of Alpine summit vegetation?

Location: Bernina region of the Swiss Alps.

Methods: Based on a data set from previous literature we expand the analysis from species richness to beta‐diversity and spatial heterogeneity. Species compositions of mountain summits are compared using a two‐component heterogeneity concept including the mean and the variance of Sørensen similarities calculated between the summits. Non‐metric multidimensional scaling is applied to explore developments of single summits in detail.

Results: Both heterogeneity components (mean dissimilarity and variance) decrease over time, indicating a trend towards more homogeneous vegetation among Alpine summits. However, the development on single summits is not strictly unidirectional.

Conclusions: The upward shift of plant species leads to homogenization of alpine summit regions. Thus, increasing alpha‐diversity is accompanied by decreasing beta‐diversity. Beta‐diversity demands higher recognition by scientists as well as nature conservationists as it detects changes which cannot be described using species richness alone.
Changing climate and historic‐woodland structure interact to control species diversity of the ‘Lobarion’ epiphyte community in Scotland
Authors: Ellis Christopher J. , Coppins Brian J.
Published: February 2009

Question: How will changing climate and habitat structure interact to control the species diversity of lichen epiphytes?

Location: Scotland.

Method: Species richness (=diversity) of the epiphyte lichen community known as Lobarion (named after Lobaria pulmonaria) was quantified for 94 Populus tremula stands across Scotland, and compared in a predictive model to seven climate variables and eight measures of woodland structure. An optimum model was selected and used to project Lobarion diversity over the geographic range of the study area, based on IPCC climate change scenarios and hypothetical shifts in woodland structure.

Results: Species diversity of the Lobarion community was best explained by three climate variables: (1) average annual temperature; (2) autumn and winter precipitation; in combination with (3) historic‐woodland extent. Projections indicate a positive effect of predicted climate change on Lobarion diversity, consistent with the physiological traits of cyanobac‐terial lichens comprising the Lobarion. However, the general response to climate is modified significantly by the effect on diversity of historic‐woodland extent.

Conclusions: Historic‐woodland extent may exert an important control over local climate, as well as impacting upon the metapopulation dynamics of species in the Lobarion. In particular, a temporal delay in the response of Lobarion species to changed woodland structure is critical to our understanding of future climate change effects. Future Lobarion diversity (e.g. in the 2050s) may depend upon the interaction of contemporary climate (e.g. 2050s climate) and historic habitat structure (e.g. 1950s woodland extent). This is supported by previous observations for an extinction debt amongst lichen epiphytes, but suggests an extension of simple climate‐response models is necessary, before their wider application to lichen epiphyte diversity.
Natural avalanche disturbance shapes plant diversity and species composition in subalpine forest belt
Authors: Rixen Christian , Haag Susanne , Kulakowski Dominik , Bebi Peter
Published: February 2009

Background: Disturbances by avalanches have created unique habitats for animals and plants in subalpine ecosystems worldwide, but at the same time avalanches can pose a major threat to humans. Thus, avalanches are suppressed by means of avalanche barriers to protect settlements and infrastructures in populated areas of the European Alps. As a consequence, the disturbance regime in avalanche tracks has fundamentally changed.

Methods: In the present study we address ecological consequences of avalanche suppression on plant diversity. We analysed plant diversity and species composition in recent and old avalanche tracks with and without avalanche suppression and in undisturbed adjacent forests at high and low elevations.

Results: The number of species was higher in both active and inactive avalanche tracks as compared to undisturbed subalpine forest. The species composition indicated a wider range of ecological niches in active than in inactive avalanche tracks. The vegetation from active tracks showed lower indicator values for temperature and nitrogen availability. The proportion of alpine species was lower in formerly active tracks.

Conclusions: The conditions that exist in active avalanche tracks increase plant diversity in relation to undisturbed forest. In the few decades following avalanche suppression, species composition changes in tracks from which avalanches have been excluded. Continued suppression of avalanche disturbance may lead to a decline in plant and habitat diversity. Avalanche disturbance can exert an important influence on the biodiversity of subalpine forests and provide important habitats. Anthropogenic changes in the natural regime of avalanche disturbance are likely to contribute significantly to future landscape changes in subalpine forests.
Improved estimates of incident radiation and heat load using non‐ parametric regression against topographic variables
Authors: McCune Bruce
Published: February 2009

Question: Can non‐parametric multiplicative regression (NPMR) improve estimates of potential direct incident radiation (PDIR) and heat load based on topographic variables, as compared to least‐squares multiple regression against trigonometric transforms of the predictors?

Methods: We used a multiplicative kernel smoothing technique to interpolate between tabulated values of PDIR, using a locally linear model and a Gaussian kernel, with slope, aspect, and latitude as predictors. Heat load was calculated as a 45 degree rotation of the PDIR response surface.

Results: This method yielded a fit to a complex response surface with R2 > 0.99 and eliminated the areas of poor fit given by a previously published method based on least squares multiple regression with trigonometric functions of the predictors.

Conclusions: Improved estimates of PDIR and heat load based on topographic variables can be obtained by using non‐parametric multiplicative regression (NPMR). The main drawback to the method is that it requires reference to the data tables, since those data are part of the model.
Effects of fertilisation and irrigation on ‘foliar afterlife’ in alpine tundra
Authors: Soudzilovskaia Nadejda A. , Onipchenko Vladimir G. , Cornelissen Johannes H.C. , Aerts Rien
Published: February 2009

Question:How do increases in soil nutrient and water availability alter the nutrient fluxes through the resorption and litter decomposition pathways and how do they affect litter nutrient pools in a low‐productive alpine tundra ecosystem?

Location:An alpine lichen‐rich tundra on Mt. Malaya Khati‐para in the NW Caucasus, Russia (43°27’ N, 41°42’ E; altitude 2800 m a.s.l.).

Methods:We conducted a 4‐year fertilisation (N, P, N+P, lime) and irrigation experiment, and analysed the responses of nutrient resorption from senescing leaves, leaf litter quality and decomposability of six pre‐dominant vascular plant species, total plant community litter production and litter (nutrient) accumulation.

Results:Vascular plant litter [N] and [P] increased 1.5 and 10 fold in response to N and P additions, due to increased concentrations of the nutrients in fresh leaves and unchanged or reduced resorption efficiency. Litter decomposability was not affected by nutrient amendments. Fertilisation enhanced litter production (180%; N+P treatment) and litter accumulation (80%; N+P), owing to tremendously increased production and low decomposability of graminoids. Together with increased litter [N] and [P] this led to great increases in total litter nutrient pools.

Conclusions:Due to increased production of graminoids, nutrients added to the alpine tundra soil were mostly immobilised in recalcitrant, nutrient‐rich litter. This suggests that changing species composition in low productive ecosystems may act as an internal buffer mechanism, which under increased soil nutrient availability prevents the community from rapidly acquiring features typical of a high productive ecosystem such as high decomposability and high nutrient availability.
The third party
Authors: Jones Clive G. , Callaway Ragan M.
Published: February 2009

Abstract. Spatial and temporal variation in interactions among plants, other species and the abiotic environment create context‐dependency in vegetation pattern. We argue that we can enhance understanding of context‐dependency by being more explicit about the kinds of direct interactions that occur among more than two living and non‐living entities (i.e., third through nth parties) and formalizing how their combinations create context‐dependency using simple conceptual models. This general approach can be translated into field studies of context‐dependency in communities by combining: progressive sampling of local variation in vegetation pattern that encompasses variation in combinations of direct interactions; spatial and temporal measures of these direct interactions; locally parameterized versions of the conceptual models; and appropriately scaled experiments.
Measuring beta‐diversity from taxonomic similarity
Authors: Bacaro Giovanni , Ricotta Carlo , Mazzoleni Stefano
Published: February 2009

Question: The utility of beta (β‐) diversity measures that incorporate information about the degree of taxonomic (dis)similarity between species plots is becoming increasingly recognized. In this framework, the question for this study is: can we define an ecologically meaningful index of β‐diversity that, besides indicating simple species turnover, is able to account for taxonomic similarity amongst species in plots?

Methods: First, the properties of existing measures of taxonomic similarity measures are briefly reviewed. Next, a new measure of plot‐to‐plot taxonomic similarity is presented that is based on the maximal common subgraph of two taxonomic trees. The proposed measure is computed from species presences and absences and include information about the degree of higher‐level taxonomic similarity between species plots. The performance of the proposed measure with respect to existing coefficients of taxonomic similarity and the coefficient of Jaccard is discussed using a small data set of heath plant communities. Finally, a method to quantify β‐diversity from taxonomic dissimilarities is discussed.

Results: The proposed measure of taxonomic β‐diversity incorporates not only species richness, but also information about the degree of higher‐order taxonomic structure between species plots. In this view, it comes closer to a modern notion of biological diversity than more traditional measures of β‐di‐versity. From regression analysis between the new coefficient and existing measures of taxonomic similarity it is shown that there is an evident nonlinearity between the coefficients. This nonlinearity demonstrates that the new coefficient measures similarity in a conceptually different way from previous indices. Also, in good agreement with the findings of previous authors, the regression between the new index and the Jaccard coefficient of similarity shows that more than 80% of the variance of the former is explained by the community structure at the species level, while only the residual variance is explained by differences in the higher‐order taxonomic structure of the species plots. This means that a genuine taxonomic approach to the quantification of plot‐to‐plot similarity is only needed if we are interested in the residual system's variation that is related to the higher‐order taxonomic structure of a pair of species plots.
Post‐dispersal granivory in a tall‐tussock grassland: A positive feedback mechanism of dominance?
Authors: Murillo Natalia , Laterra Pedro , Monterubbianesi Gloria
Published: February 2009

Questions: Is post‐dispersal seed predation a factor contributing to a positive feedback mechanism for dominance of tall‐tussock grasslands? Do seeds dispersed into neighbouring microhabitats of contrasting dominance differ in their probabilities of being predated? Does predation rate vary among predator groups? Do seed eaters selectively forage among the available seeds?

Location: The southern and flooding sub‐regions of the Argentinian Pampas.

Methods: We examined seed predation by vertebrate and invertebrate predators within two microhabitats of grassland mosaics (highly dominated tall‐grass patches vs. scarcely dominated short‐grass matrix) for different seed species in semi‐natural grasslands. Proportion of seeds eaten by different predator groups was estimated through exclusion experiments and analysed using ANOVA for split‐split‐plot designs. Experiments were performed during the autumn of two consecutive years in both Pampa sub‐regions.

Results: Removal of seeds after a five day trial was two to four times higher in the tall‐grass patches than in the short‐grass matrix. During the same period, vertebrate predation was six times higher than invertebrate predation in the tall‐grass phase of the Southern Pampa, but it did not differ in the short‐grass matrix. Relative predation among phases showed the same pattern in the Hooding Pampa, where preferences by seed species also varied according to phase.

Conclusions: The highest predation intensity shown by vertebrates in the tall‐grass patches indicates that they are the main seed predators in these systems, possibly because this microhabitat grants them refuge against carnivorous predators. This could significantly reduce the available seeds for recruitment of subordinate species after different disturbance events (fires, trampling by large herbivores, burrowing), representing an active filter to the floristic composition of the patch and contributing with other mechanisms to the dominance of tall‐grass species.
Woody vegetation of a mosaic of protected areas adjacent to the Kruger National Park, South Africa
Authors: Peel M.J.S. , Kruger J.M. , MacFadyen S.
Published: February 2009

Question: How is pattern detected and spatial scale defined in a manner that is meaningful to management?

Location: Protected areas to the west of the Kruger National Park, South Africa.

Methods: A Two‐Way Indicator Species Analysis (TWIN‐SPAN) based on composition and structure was applied to woody survey data. The resulting TWINSPAN classes for individual monitoring sites were used in a supervised classification of Landsat ETM+ imagery across the study area. The training sample's co‐ordinates were fed into a GIS and the resulting TWINSPAN point‐feature shape file was processed using a 1 km theme‐buffer function.

Results: The supervised classification using the theme‐buffer signatures yielded a satisfactory overall accuracy (κ= 0.75; r2= 0.80; p= 0.05) using a test sample compiled by reserve wardens throughout the study area. The derived vegetation map was smoothed using a majority filter and after on‐screen digitizing a small gabbro intrusion, it was accepted as the best representation of the woody vegetation of the study area at a scale of 1:250 000. Seven plant communities were identified in the current study and satisfactorily accommodated within various topographical units of four extrapolated Landscapes of the Kruger National Park.

Conclusions: Vegetation patterns are described of the areas under conservation management to the west of the KNP at a spatial scale that allows for the meaningful examination and comparison of the structure, functioning, and ultimately effective management, of these savannas. This contribution thus links to the co‐ordinated effort extending into the Trans‐Frontier National Park in Mocambique. A key objective is to better understand the functioning of these savanna systems for effective management and we discuss some of the key ecological issues within the plant communities of each landscape. The latter illustrate the usefulness of the technique in practice.
Small gap dynamics in the southern boreal forest of eastern Canada: Do canopy gaps influence stand development?
Authors: de Römer André H. , Kneeshaw Daniel D. , Bergeron Yves
Published: February 2009

Question: To what extent do small‐scale disturbances in the forest canopy, created by natural disturbance agents, affect stand development? Doubts exist as to whether small canopy openings have any real effect on the understory tree recruitment, especially in boreal forests.

Location: Conifer and mixed stands in the Gaspesian region in eastern Québec. The main natural disturbance agents are recurring outbreaks of Choristoneura fumiferana (eastern spruce budworm) and winds.

Methods: Linear transects in 27 sites were used to describe the gap (< 0.1 ha) regime parameters, including gap fraction, gap size and change in disturbance severity through time. Three stand types were distinguished, based on a gradient of abundance of tree host species for the eastern spruce budworm. The impact of gaps was evaluated on the basis of changes in the number, the period of recruitment, and the composition of tree saplings present within gap areas. Changes were measured along the gap size gradient, and according to the pattern of recent budworm epidemics.

Results: The gap fraction is highly variable (18%‐64%) and is on average relatively high (42%). Gap sizes have a positively skewed distribution. In most cases the growth rate among gap filling saplings increased sufficiently to date disturbance events. The composition and the structure of understory trees were affected by gap formation. The number of shade‐intolerant tree species did increase during or following periods of particularly severe canopy disturbances. However, the establishment or survival of shade intolerant species was not restricted to larger gaps or more intensely disturbed periods.

Conclusions: In sub‐boreal forests of Eastern Canada, small scale disturbances in the tree canopy influence stand regeneration dynamics, but not to the extent that parameters such as sapling composition and recruitment patterns depend on gap regime characteristics.
Semi‐dry grasslands along a climatic gradient across Central Europe: Vegetation classification with validation
Authors: Illyés Eszter , Chytrý Milan , Botta‐Dukát Zoltán , Jandt Ute , Škodová Iveta , Janišová Monika , Willner Wolfgang , Hájek Ondřej
Published: February 2009

Question: What is the variation in species composition of Central European semi‐dry grasslands? Can we apply a training‐and‐test validation approach for identifying phytosociological associations which are floristically well defined in a broad geographic comparison; can we separate them from earlier described associations with only a local validity?

Location: A 1200 km long transect running along a gradient of increasing continentality from central Germany via Czech Republic, Slovakia, NE Austria, Hungary to NW Romania.

Methods: Relevés with > 25% cover of Brachypodium pin‐natum and/or Bromus erectus were geographically selected from a larger database. They were randomly split into two data sets, TRAINING and TEST, each with 422 relevés. Cluster analysis was performed for each data set on scores from significant principal coordinates. Different partitions of the TRAINING data set were validated on the TEST data set, using a new method based on the comparison of % frequencies of species occurrence in clusters. Clusters were characterized by statistically defined groups of diagnostic species and values of climatic variables.

Results: Species composition changed along the NW‐SE gradient and valid clusters were geographically well separated. Optimal partition level was at 11 clusters, six being valid: two clusters Germany and the Czech Republic corresponded to the Bromion erecti; two clusters from the Czech Republic and Hungary to the Cirsio‐Brachypodion, and two clusters were transitional between these two alliances.

Conclusion: The training‐and‐test validation method used in this paper proved to be efficient for discriminating between robust clusters, which are appropriate candidates for inclusion in the national or regional syntaxonomic overviews, and weak clusters, which are specific to the particular classification of the given data set.
Plant dispersal strategies and the colonization of Araucaria forest patches in a grassland‐forest mosaic
Authors: Duarte Leandro da S. , Carlucci Marcos B. , Hartz Sandra M. , Pillar Valério D.
Published: February 2009

Questions: In a natural grassland‐forest mosaic: What is the influence of phylogeny and diaspore traits related to disperser attraction (DAT) on (1) seed size/number trade‐off (SSNT) in woody species colonizing forest patches; (2) on the frequency of the species? 3. What is the influence of forest patch area on mean seed size and number. 4. Do phylogeny and DAT expressed at the species level affect this relationship?

Location: Campos grassland and Araucaria forest in São Francisco de Paula, RS, Brazil, at ca. 29°28’ S; 50° 13’ W.

Methods: Forest patches of different sizes in a grassland site recovering for ten years since human disturbances were surveyed by the relative abundance of vertebrate‐dispersed woody saplings. We described colonizer species according to taxonomic phylogenetic relationships and diaspore type, size and color. We analyzed with a variation partitioning method their influence on SSNT and on species frequency in the patches. At the community level we regressed mean seed size and number on forest patch area and evaluated how these relationships were affected by phylogeny and DAT at the species level.

Results: 1. Phylogeny and DAT mostly explained seed size and seed number per diaspore variation. 2. By controlling phylogeny and DAT influence the frequency of species in forest patches was positively associated with their seed number in the diaspores, and negatively associated with their seed size. 3. Mean seed size and seed number at the community level were positively associated with patch area. 4. When phylogeny and DAT influences on seed size were removed this relationship was stronger for seed size and weaker for seed number.

Conclusions: 1. Energy allocation to dispersal in detriment of offspring survival increased the successful establishment of colonizer species in forest patches, despite phylogenetic relationships and DAT variation in their diaspores. 2. Although patch area exerted a selective pressure on seed size, habitat preferences of dispersers may also influence patch colonization.
Control of mammalian gene expression by amino acids, especially glutamine
Authors: Brasse‐Lagnel Carole , Lavoinne Alain , Husson Annie
Published: February 2009

Molecular data rapidly accumulating on the regulation of gene expression by amino acids in mammalian cells highlight the large variety of mechanisms that are involved. Transcription factors, such as the basic‐leucine zipper factors, activating transcription factors and CCAAT/enhancer‐binding protein, as well as specific regulatory sequences, such as amino acid response element and nutrient‐sensing response element, have been shown to mediate the inhibitory effect of some amino acids. Moreover, amino acids exert a wide range of effects via the activation of different signalling pathways and various transcription factors, and a number of cis elements distinct from amino acid response element/nutrient‐sensing response element sequences were shown to respond to changes in amino acid concentration. Particular attention has been paid to the effects of glutamine, the most abundant amino acid, which at appropriate concentrations enhances a great number of cell functions via the activation of various transcription factors. The glutamine‐responsive genes and the transcription factors involved correspond tightly to the specific effects of the amino acid in the inflammatory response, cell proliferation, differentiation and survival, and metabolic functions. Indeed, in addition to the major role played by nuclear factor‐κB in the anti‐inflammatory action of glutamine, the stimulatory role of activating protein‐1 and the inhibitory role of C/EBP homology binding protein in growth‐promotion, and the role of c‐myc in cell survival, many other transcription factors are also involved in the action of glutamine to regulate apoptosis and intermediary metabolism in different cell types and tissues. The signalling pathways leading to the activation of transcription factors suggest that several kinases are involved, particularly mitogen‐activated protein kinases. In most cases, however, the precise pathways from the entrance of the amino acid into the cell to the activation of gene transcription remain elusive.
Differential recognition of heat shock elements by members of the heat shock transcription factor family
Authors: Yamamoto Noritaka , Takemori Yukiko , Sakurai Mayumi , Sugiyama Kazuhisa , Sakurai Hiroshi
Published: February 2009

Heat shock transcription factor (HSF), an evolutionarily conserved stress response regulator, forms trimers and binds to heat shock element (HSE), comprising at least three continuous inverted repeats of the sequence 5′‐nGAAn‐3′. The single HSF of yeast is also able to bind discontinuously arranged nGAAn units. We investigated interactions between three human HSFs and various HSE types in vitro, in yeast cells, and in HeLa cells. Human HSF1, a stress‐activated regulator, preferentially bound to continuous HSEs rather than discontinuous HSEs, and heat shock of HeLa cells caused expression of reporter genes containing continuous HSEs. HSF2, whose function is implicated in neuronal specification and spermatogenesis, exhibited a slightly higher binding affinity to discontinuous HSEs than did HSF1. HSF4, a protein required for ocular lens development, efficiently recognized discontinuous HSEs in a trimerization‐dependent manner. Among four human γ‐crystallin genes encoding structural proteins of the lens, heat‐induced HSF1 preferred HSEs on the γA‐crystallin and γB‐crystallin promoters, whereas HSF4 preferred HSE on the γC‐crystallin promoter. These results suggest that the HSE architecture is an important determinant of which HSF members regulate genes in diverse cellular processes.
Global Expression Profiling in Epileptogenesis: Does It Add to the Confusion?
Authors: Wang Yi Yuen , Smith Paul , Murphy Michael , Cook Mark
Published: February 2009

Since the inception of global gene expression profiling platforms in the mid‐1990s, there has been a significant increase in publications of differentially expressed genes in the process of epileptogenesis. In particular for mesial temporal lobe epilepsy, the presence of a latency period between the first manifestation of seizures to chronic epilepsy provides the opportunity for therapeutic interventions at the molecular biology level. Using global expression profiling techniques, approximately 2000 genes have been published demonstrating differential expression in mesial temporal epilepsy. The majority of these changes, however, are specific to laboratory or experimental conditions with only 53 genes demonstrating changes in more than two publications. To this end, we review the current status of gene expression profiling in epileptogenesis and suggest standard guidelines to be followed for greater accuracy and reproducibility of results.
Performance evaluation of the PENTRA 60C+ automated hematology analyzer and comparison with the ADVIA 2120
Authors: GUERTI K. , VERTESSEN F. , DANIËLS L. , VAN DER PLANKEN M.
Published: February 2009

The PENTRA 60C+ hematology analyzer provides a complete blood cell (CBC) count, including a five‐part differential (5‐DIFF) count and two leukocyte subpopulations, i.e. large immature cells (LIC’s) and atypical lymphocytes (ALY’s). We evaluated its analytical performance and assessed agreement with the ADVIA 2120, in order to install the analyzer in a small satellite hematology laboratory. First we assessed repeatability, reproducibility and carry‐over to evaluate the analytical performance. Then we used Pearson correlation coefficients, Passing and Bablok regression analysis and a graphical approach (n = 209) to evaluate agreement with the ADVIA 2120. Repeatability and reproducibility were excellent for the majority of CBC and 5‐DIFF count parameters. Carry‐over was negligible. Our data showed very good correlation for most CBC count parameters. Lower correlation coefficients were observed for red cell distribution width, mean corpuscular volume and mean platelet volume. As compared to the ADVIA 2120, the 5‐DIFF count performed very well. Agreement was poorer for low‐level eosinophils and basophils. Furthermore, the PENTRA 60C+ was equally able to identify pathological blood samples through the determination of LIC’s and ALY’s. Therefore, the PENTRA 60C+ is an eligible blood cell counter to be operational in a satellite laboratory setting.
Quality assurance for point‐of‐care testing of oral anticoagulation: a large‐scale evaluation of the Hemochron Junior Signature Microcoagulation System
Authors: MADDOX J. M. , BOGO P. H. , McGREGOR E. , PIPPARD M. J. , KERR R.
Published: February 2009

We report the first large‐scale evaluation of the Hemochron Junior Signature (HJS) Microcoagulation System for community monitoring of oral anticoagulation and establishment of a programme of internal and external quality assurance. Over 1600 HJS results, with a simultaneous venous sample for central analysis, were obtained over a 19 month period. Monitoring of an initial period of HJS results (n = 135) revealed an International Normalized Ratio (INR) over estimation (mean +1.05), with only 27% of results within 0.5 of the central laboratory INR. A correction factor was introduced which reduced the INR bias to +0.07 and improved the percentage of results within 0.5 of the central laboratory INR to 76% (n = 353). A revised correction factor was later introduced to adjust for an under estimation at higher INR values. This changed the INR bias to –0.05, with 76% of results within 0.5 of the central laboratory INR (n = 1174). Local external quality assurance samples were distributed monthly with a total of 791 samples during the study period. 84% of test results were within 15% of the median value (range 73–97% per month). These results emphasize the value of a robust quality assurance programme when using point‐of‐care devices for community monitoring of oral anticoagulation.
Serum macrophage migration inhibitory factor (MIF) levels after allogeneic hematopoietic stem cell transplantation
Authors: TOUBAI T. , SHONO Y. , NISHIHIRA J. , IBATA M. , SUIGITA J. , KATO N. , OHKAWARA T. , TONE S. , LOWLER K. P. , OTA S. , TANAKA J. , ASAKA M. , REDDY P. , IMAMURA M.
Published: February 2009

Macrophage migration inhibitory factor (MIF) may play an important role in the pathogenesis of acute graft‐versus‐host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo‐HSCT), as MIF plays an important role to regulate the production of tumor necrosis factor‐α (TNF‐α), one of the inflammatory cytokines which induces and exacerbates aGVHD. We examined the association between serum MIF levels and aGVHD vs. chronic GVHD (cGVHD) in allo‐SCT patients in this study. We found a significant increase in the peak serum MIF (14.46 ng ± 1.47 ng/ml) at onset in patients that developed aGVHD (n = 23, P = 0.009). We also found that mean serum MIF levels in patients who developed extensive type cGVHD within 6 months (12.58 ± 2.18 ng/ml, n = 13) were significantly higher than MIF levels before allo‐HSCT (7.86 ± 1.17 ng/ml, n = 19, P = 0.04). Therefore, we speculated that serum MIF levels increase during the active phase of both aGVHD and cGVHD.
Measurement of CD4+ T cells in point‐of‐care settings with the Sysmex pocH‐100i haematological analyser
Authors: BRIGGS C. , MACHIN S. , MÜLLER M. , HAASE W. , HOFMANN K. , FORSTREUTER F. , HINZMANN R.
Published: February 2009

The decision to provide antiretroviral therapy to HIV‐positive patients mainly depends on the CD4+ T‐cell count, with therapy indicated at a cut‐off value of <350–200 CD4+ T cells/μl blood. Monitoring patients is still a major problem in countries with limited resources where blood samples often have to be transported over long distances to regional referral centres in which the count can be performed on flow cytometers. We have evaluated a newly developed simple and inexpensive method for CD4+ T‐cell quantification. It is a variation of the Invitrogen T4 Quant kit, with manual isolation of nuclei from CD4+ T cells and subsequent counting on the small haematology analyser pocH‐100i, Sysmex. We have demonstrated that this new method is highly reproducible and gives stable and linear results over a wide range of CD4+ T‐cell concentrations. Method comparison to two different flow cytometers showed excellent correlation with concordances of about 93%. Overall, this method is rapid, easy to perform and offers a good reliable alternative to measurement by flow cytometry. The pocH‐100i has the additional benefit of providing a complete blood count with a three‐part white blood cell differential and software for patient data storage and handling.
Elevated expression of IL‐12 and IL‐23 in patients with aplastic anemia
Authors: GU Y. , ZHANG J. , PENG J. , HU X. , XU C.
Published: February 2009

Aplastic anemia (AA), which is characterized by hypocellular bone marrow (BM) and blood pancytopenia, was considered as a T‐helper1 (Th1) mediated disease. Interleukin (IL)‐12 and IL‐23 produced by antigen presenting cells are essential for inducing and sustaining Th1 effector cells via different pathways. However, less is known with regard to the levels of expression and synthesis of these two cytokines in patients with AA. This was determined in the current study in 26 patients with AA as well as in 20 healthy controls. Our results showed that IL‐12 p40, IL‐12 p35 and IL‐23 p19 gene expression can be detected in all samples both from the patients and the controls, using real‐time reverse transcription polymerase chain reaction. Furthermore, an increased expression of IL‐12 p40, IL‐12 p35 and IL‐23 p19 mRNA was observed in bone marrow mononuclear cells and peripheral blood mononuclear cells of patients with AA compared with the corresponding one in normal controls. Higher levels of IL‐12 and IL‐23 were also found in BM plasma and PB plasma in patients with AA than in normal controls. Therefore, the augmented expression of IL‐12 and IL‐23 in patients with AA may play an important role in the pathogenesis of this disease.
Psychological Characteristics and Social Integration of Patients with Ischemic and Non‐Ischemic Heart Failure Newly Listed for Heart Transplantation: The Waiting for a New Heart Study
Authors: Spaderna Heike , Weidner Gerdi , Zahn Daniela , Smits Jacqueline M.A.
Published: February 2009

It is not known whether psychosocial risk factors for coronary artery disease (CAD) are present in patients listed for heart transplantation (HTx). The aim of this study was to examine whether HTx candidates with ischemic heart failure (due to CAD) have an adverse psychological risk profile and reduced social integration compared to patients with non‐ischemic etiology. In the multi‐site study “Waiting for a New Heart”, waiting‐list‐related stressors, depression, anxiety, trait‐anger, anger‐expression, dispositional coping, social integration, and social support were assessed in 318 newly registered HTx candidates (53.5 ± 11.4 years, 18% female, left ventricular ejection fraction <25%). Medical parameters at time of listing were provided by Eurotransplant. Analyses revealed a high level of stress (on average 70% of 50 HTx‐related stressors), and signs of clinical depression in 39 per cent of the sample. Social integration was correlated with reduced depression (p < .05). While ischemic and non‐ischemic groups were comparable in terms of disease severity, men with CAD reported significantly more anxiety, anger, anger‐in, and less social integration than non‐ischemic men after adjusting for age and marital status (ps < .05). To conclude, psychosocial stress is common in HTx candidates, particularly in men with underlying CAD. Thus, targeting psychosocial stress and increasing social integration may enhance well‐being in patients waiting for a new heart.
Mechanical stretch promotes fetal type II epithelial cell differentiation via shedding of HB‐EGF and TGF‐α
Authors: Wang Yulian , Maciejewski Benjamin S. , Soto‐Reyes Dariana , Lee Hyeon‐Soo , Warburton David , Sanchez‐Esteban Juan
Published: February 2009

The mechanisms by which mechanical forces promote fetal lung development are not fully understood. Here, we investigated differentiation of fetal type II epithelial cells via the epidermal growth factor receptor (EGFR) in response to mechanical strain. First, we showed that incubation of embryonic day (E) 19 fetal type II cells with recombinant heparin‐binding EGF‐like growth factor (HB‐EGF) or transforming growth factor (TGF)‐α, but not with amphiregulin (AR), betacellulin (BTC) or epiregulin (EPR), increased fetal type II cell differentiation, as measured by surfactant protein B/C mRNA and protein levels. Next, we demonstrated that 5% cyclic stretch of E19 monolayers transfected with plasmid encoding alkaline phosphatase (AP)‐tagged ligands shed mature HB‐EGF and TGF‐α into the supernatant and promoted type II cell differentiation. Release of these ligands was also observed in E19 cells subjected to higher degrees of cyclic strain, but not in cells exposed to continuous stretch. Interestingly, the addition of fibroblasts to type II cell cultures did not enhance release of HB‐EGF. Whereas HB‐EGF shedding was also detected in E18 cells exposed to 5% cyclic stretch, release of this ligand after 2.5% sustained stretch was restricted to cells isolated on E18 of gestation. In addition, mechanical stretch released EGF, AR and BTC. We conclude that mechanical stretch promotes fetal type II cell differentiation via ectodomain shedding of HB‐EGF and TGF‐α. The magnitude of shedding varied depending on gestational age, ligand, and strain protocol. These studies provide novel mechanistic information potentially relevant to fetal lung development and to mechanical ventilation‐induced lung injury.