bluuebunny/crossref_metadata_2025 huggingface dataset:
Top‐soil translocation as a technique in the re‐creation of species‐rich meadows
Authors: Vécrin M.P. , Muller S.
Published: February 2009

Abstract. In France, most civil engineering and excavation projects are at present accompanied by compensatory measures with the aim of preserving biodiversity. In order to avoid the destruction of a habitat of high conservation interest in NE France, harbouring two legally protected plant species, an experiment of soil translocation was conducted on an area of 1 ha. The donor site was an extensively managed mesophilic meadow and the receiving site was a neighbouring arable land. The vegetation of the translocated meadow was described 8 and 17 months after soil translocation, and compared (1) with vegetation resulting from more classical restoration techniques tested on the arable land (natural regeneration and seed mixture sowing) and (2) with the soil seed bank and vegetation previously present on the donor site. Results showed that the soil translocation technique permitted the development of many meadow species, including two legally protected species, and few ruderal species despite a large area of bare ground. This technique seems effective in terms of number and abundance of meadow species compared to natural regeneration and commercial seed sowing. In the case of the two classical methods, species richness was lower and only widespread species were present. Topsoil translocation provides a good compensatory method to avoid habitat and species destruction. However, the study should be continued, with the aim of assessing the longer term development and stabilization of the vegetation of the translocated meadow.
Phenological description of natural vegetation in southern Africa using remotely‐sensed vegetation data
Authors: Hoare David , Frost Phillip
Published: February 2009

Abstract. Various attempts have been made to describe and map the vegetation of southern Africa with recent efforts having an increasingly ecologi cal context. Vegetation classification is usually based on vegetation physiognomy and floristic composition, but phenology is useful source of information which is rarely used, although it can contribute functional information on ecosystems. The objectives of this study were to identify a suite of variables derived from time‐series NDVI data that best describe the phenological phenomena of vegetation in southern Africa and, secondly, to assess a classification of pixels of the study area based on NDVI variables using a preexisting map of the biomes that was delimited on the basis of life forms and climate. A number of variables were derived from the satellite data for describing phenological phenomena, which were analysed by multivariate techniques to determine which variables best explained the variation in the satellite data. This set of variables was used to produce a phenological classification of the vegetation of southern Africa, the results of which are discussed in relation to their concordance with the existing biome boundaries.
Immediate increase in plant species richness after clear‐cutting of boreal herb‐rich forests
Authors: Pykälä Juha
Published: February 2009

Abstract. The flora of clear‐cuttings with soil scarification in forests was compared < 1–2 yr after cutting with that in mature herb‐rich forests in SW Finland. The total and mean numbers of vascular plant species both in the study areas and in the sample plots, were almost double in clear‐cut areas compared to mature forests. Clear‐cuttings and mature forests were distinctly separated by multivariate analyses (DCA). Several dozen species not found in forests were common in clear‐cut areas. Most of them probably belong to the neglected native species pool of early boreal forest succession and are dependent on the long‐term persistent seed bank or effective wind dispersal. It is emphasized that in forests many plant species are confined to the very early stages (< 2 yr) after disturbance. The storage effect of the long‐term persistent seed bank is crucial for the maintenance of plant diversity in boreal forests. Probably a considerable part of the flora of agricultural areas is composed of species that were originally disturbance dependent forest plants. Scarification is beneficial to disturbance dependent plants and may be useful in restoration of populations of species of early succession.
Effects of rock climbing on plant communities on exposed limestone cliffs in the Swiss Jura mountains
Authors: Rusterholz Hans‐Peter , Miiller Stefan W. , Baur Bruno
Published: February 2009

Abstract. Exposed cliffs of the Swiss Jura mountains harbour a highly diverse flora with many rare and endangered plant species. Many cliffs are frequently visited by rock climbers. We examined the impact of rock climbing on vascular plants in the lower part of four cliffs of the Gerstelflue (NW Switzerland) by comparing the vegetation of climbed and unclimbed areas. In climbed areas plant cover and species density were reduced. Similarly, the density of forbs and shrubs decreased, whereas the density of ferns tended to increase. In addition, rock climbing caused a significant shift in plant species composition and altered the proportions of different plant life forms. Rock climbing can be a threat to sensitive plants of the limestone cliff community.
Restoration, succession and climatic change
Authors: Wilson J. Bastow , White Peter S. , Bakker Jan P. , Díaz Sandra
Published: February 2009

Two outstanding papers on restoration and succession are briefly discussed as model papers for the type of research papers Appl. Veg.Sci. should publish. The paper on restoration concentrates on the introduction of hay to a site in order to speed up the introduction of target species. The paper on succession discusses the importance of plant colonization ‘windows’ opened by extreme weather events for succession and for offering optimum periods for intervention in restoration practice.

Some remarks are also made on the electronic availability of ecology papers.
Population structure of the threatened perennial Serratula tinctoria in relation to vegetation and management
Authors: Bissels Stephanie , Hölzel Norbert , Otte Annette
Published: February 2009

Question: How does vegetation and management affect the population stage structure of Serratula tinctoria, a species indicative of highly endangered and species‐rich flood‐plain meadows? Are different management regimes suitable to support viable populations of S. tinctoria?

Location: Flood‐plain of the northern Upper Rhine, Germany.

Methods: We analysed the population structure of S. tinctoria at 24 meadow sites which differed in vegetation and management. In this comparative study the investigated meadows were either (1) late mown in September; (2) early mown in June or (3) mown in June and then grazed by sheep.

Results: The structure of the surrounding vegetation had a clear effect on the population structure of S. tinctoria. The percentage of bare soil, as well as the cover of bryophytes, were positively related, whereas the Ellenberg N‐value of the established vegetation was negatively related to the density and proportion of seedlings. Generally, we found only slight differences between the population structure of S. tinctoria in early and late mown meadows. Both management regimes had high densities of seedlings. In contrast, the meadow pastures supported significantly lower densities of seedlings and generative adults but relatively high densities of juveniles and vegetative adults, indicating a greater importance of clonal propagation under grazing pressure.

Conclusions: Our results clearly showed that viable populations of S. tinctoria may occur in all of the studied management regimes. Although S. tinctoria was considered to be highly sensitive to early mowing, our findings suggest a facilitation of the species at more nutrient‐rich sites by mowing in June, which is also a benefit for the integration of management in farming systems.
Effects of fire on soil respiration, ATP content and enzyme activities in Mediterranean maquis
Authors: Fioretto A. , Papa S. , Pellegrino A.
Published: February 2009

Question: Do low or high intensity fires affect micro‐organism activity in the upper soil layer of Mediterranean maquis?

Location: 600 m from the sea in the Nature Reserve of Castel Volturno (Campania, southern Italy, 40°57’N; 13°55’E).

Methods: Soil respiration was measured in situ on intact soil; enzyme activity (cellulase, xylanase, invertase, trehalase and protease) and ATP content were measured on soil samples collected under three species of maquis vegetation: Phillyrea angustifolia L., Myrtus communis L. and Cistus incanus L.

Results: Soil microbial respiration showed no significant differences in CO2 flux in treated and untreated plots, but the ATP content in the soil under C. incanus and M. communis was lower in the treated plots for most of the study period. In the soil under Ph. angustifolia, ATP content was low only for one week after fire. The reduction was more marked in the samples from ‘high fire intensity’ than from ‘low fire intensity’ plots. Soil respiration and ATP content exhibited seasonal variations linked to soil water content. Among the enzyme activity measured in the soil under the three plant covers, only invertase declined in burned plots throughout the study period, particularly in the ‘high fire intensity’ plots. Activity of the enzymes cellulase, xylanase, trehalase and protease had a different sensitivity depending on the respective shrub cover.

Conclusions: Impact of fire on soil microbial activity is largely dependent on vegetation mosaic and species identity.
Recording relative water table depth using PVC tape discolouration: Advantages and constraints in fens
Authors: Navrátilová Jana , Hájek Michal
Published: February 2009

Question: Recognizing water table dynamics in wetlands is crucial for understanding species‐environment relationships, ecosystem function and changes during restoration. The PVC tape discolouration method enables spatially and temporally extensive studies of reductive conditions associated with long‐term water table dynamics in peat soils. The reliability of the method has been verified only for ombrotrophic bogs, even though wide usage can be expected in minerotrophic fens.

Location: Třreboň basin, Czech Republic.

Methods: Using data from 49 plots in six poor and moderately rich fens, we correlated the directly measured lowest, highest and mean water table depths and the same variables indicated by discolouration of PVC tape attached to green bamboo stakes installed vertically in the soil profile.

Results: The depth to the first sign of PVC discolouration was highly correlated with the directly measured position of the highest water table, the correlation between the depth of complete discolouration and the directly measured position of the lowest water table was poorer. The accuracy of the minimum water table measurement depended on the depth of the peat layer. Surprisingly, the depth at which the green bamboo stakes turned brown correlated highly with the minimum water table.

Conclusions: The PVC tape discolouration method reliably indicates water table maxima in fens, but minima are not accurately indicated. The depth of the green bamboo discolouration is suggested as a new alternative indicator of the minimum water table, even in fens and mineral soils. Combining both methods enables efficient monitoring of water table dynamics at a large number of mire sites.
Early stages of Calluna vulgaris regeneration after burning of coastal heath in central Norway
Authors: Nilsen Liv S. , Johansen Line , Velle Liv G.
Published: February 2009

Questions: How does Calluna vulgaris regenerate after burning wet and dry heaths of different age?

Location: Central Norway.

Methods: Patches of Calluna dominated old and young wet heath and old dry heath were burned. The mean temperatures reached in the categories of heath were measured. Cover, frequency, height and number of seedlings of Calluna were studied in plots.

Results: The mean burning temperatures varied from 680 to 740°C, and were highest in wet heath that had not been burned for at least 50 years. Regeneration of Calluna was evident in the year of burning, but only from seeds. Even heath with a short burning interval lacked vegetative regeneration. Calluna cover increased yearly and exceeded 50 % three years after burning. Regeneration was evident in the year of burning, and was highest in heath with a short burning interval. The height increased regularly at all sites, but was most rapid in dry heath, probably because of better microclimatic conditions. There were more seedlings in the heath with a short burning interval.

Conclusions: Calluna only regenerates from seeds afterburning in central Norway. The density of Calluna increased rapidly, which is positive for the conservation and management of coastal heaths in central Norway.
Comparing PAR transmission models for forest understorey vegetation
Authors: Stadt Kenneth J. , Lieffers Victor J.
Published: February 2009

Question: Do Beer's Law models, multi‐layer scattering models, and a semi‐empirical model for predicting PAR transmission through understorey vegetation give comparable results? Do different driving variables (LAI, PLAI and percentage cover) give different results? How do the models vary when fit with species‐specific, species‐average and the ‘default’ parameters recommended in the literature?

Location: Upland boreal forests of western North America.

Methods: In calibration and validation plots, PAR transmission was measured, total cover visually estimated, and leaf dispersion, PLAI and cover estimated for each species using a point‐frame. Leaf inclination was measured by clinometer. PAR transmission was modelled using empirically‐fit Beer's Law models, a semi‐empirical model based on hemispherical gap fraction and first‐order scattering, and a multi‐layer model allowing multiple scattering. All models were modified to use leaf area index (LAI), vertically projected leaf area index (PLAI), or percentage cover data.

Results: The empirical Beer's Law models had the least bias and best precision in predicting PAR transmission. The semi‐empirical model also had little bias and good precision, since the scattering coefficient compensated for problems in the estimation of gap fraction. The multi‐layer model consistently underestimated transmission. There was little benefit in accounting for species separately. LAI and PLAI‐based models were the most precise, but percentage cover models also provided reasonable predictions of PAR transmission.

Conclusions: PAR transmission through forest understories can be simply modelled with Beer's Law using one empirical coefficient representing the average understorey species. More complex scattering models are less effective, likely because they fail to account for the complexity of the dispersion of this vegetation layer and its effect on radiation scattering.
Effects of fire on the structure and diversity of a Spartina argentinensis tall grassland
Authors: Feldman Susana R. , Lewis J.P.
Published: February 2009

Question: What are the effects of fire on the structure and the diversity of a Spartina ar gentinensis tall grassland in the short and medium run. S. argentinensis is the dominant species of tall grasslands on inland marshes of the Chaco‐Pampean region (Argentina), where spontaneous or man‐made fires are very frequent.

Location: Federico Wildermuth Reserve (31°57′S; 61°23′W), Province of Santa Fe, Argentina, an area never ploughed that supported cattle until its exclusion in 1988.

Methods: Vegetation was surveyed in randomly placed permanent plots using the Braun‐Blanquet cover‐abundance scale. The data were analysed by multivariate methods (PCA and MRPP) for synthesizing information and testing hypotheses.

Results: Fire did not have a long‐lasting effect on the tall grassland. There was only a temporarily reduction of cover‐abundance of S. argentinensis which allowed an increase in the number of accompanying species such as Heliotropium curassavicum, Pluchea sagittalis, and Verbena litoralis and of some naturalised or weed species, such as Melilotus alba and Cirsium vulgare, respectively. Fire increased diversity, which remained relatively high for two to three years. Three years after the fire there were no significant differences on the amount of litter accumulated on burned and unburned plots.

Conclusion: Fire should be considered an intrinsic part of the dynamics of S. argentinensis tall grassland.
Vegetation and seed bank in a calcareous grassland restored from a Pinus forest
Authors: Bistea E. , Mahy G.
Published: February 2009

Question: What is the importance of the seed bank in the maintenance of the restoration potential of a 60‐year‐old abandoned calcareous grassland overgrown by Pinus trees?

Location: ‘Les Pairées’, province of Luxembourg, Belgium.

Methods: The seed bank and the above‐ground vegetation were surveyed in three adjacent stands, previously forming a unique calcareous grassland: a 60‐year‐old Pinus forest, a four‐year‐old clear‐cutting and a typical calcareous grassland. Floristic diversity was compared among stands and between vegetation and seed bank.

Results: The species richness of the vegetation and the seed bank was significantly lower in the Pinus forest. More floristic similarities were found between the clear‐cutting and the calcareous grassland. Seed bank was essentially transient, dominated by annual species. Its correspondence with the above‐ground vegetation was weak.

Conclusion: Very few calcareous grassland species have persisted in the Pinus stand. Four years after clear‐cutting, the stand was nearing restoration towards a calcareous grassland. Seed longevity in the soil was not the most explicative factor. Dispersal of propagules from adjacent sources was also important.
Conservation and restoration of the Pinus palustris ecosystem
Authors: Gilliam Frank S. , Platt William J.
Published: February 2009

Abstract. The well‐documented decline of the Pinus palustris ecosystem has resulted from several anthropogenic influences, such as forest clearing (e.g. pine plantation forestry, agriculture) and urban development, both of which are closely related to increases in human populations. Other impacts have arisen from alterations in disturbance regimes responsible for maintaining the structure and function of these ecosystems. Restoration and management of degraded pine savanna ecosystems is critical. Identification of ecological processes that determine the structure and function of the intact system are important because successful restoration efforts should be based on sound scientific understanding. In this paper, we introduce this special issue on the ecology, conservation, and restoration of the Pinus palustris ecosystem. Some global climate change scenarios have suggested that future changes may occur that alter frequency and severity of disturbances such as fires and hurricanes. Such changes may have large effects on pine stands, and ultimately entire Pinus palustris savanna ecosystems, thus presenting further challenges to their sustainable management.
Pine savanna overstorey influences on ground‐cover biodiversity
Authors: Platt William J. , Carr Susan M. , Reilly Matthew , Fahr Jean
Published: February 2009

Question:Does the overstorey of pine savannas influence plant species biodiversity in the ground cover?

Location:Camp Whispering Pines (30°41’N; 90°29’W), eastern Louisiana (USA).

Methods:We used ecologically sensitive restoration logging to remove patches ofPinus palustris(longleaf pine) in a second‐growth loess plainPinus palustrissavanna managed using frequent lightning season fires. Five years later, we measured numbers of vascular plant species and transmitted light in replicated 100‐m2plots. Treatments involved three different overstorey conditions: no overstorey for 5 years, no overstorey for several decades, and overstorey pines present for decades.

Results:Both recent and long‐term openings contained, on average, about 100 vascular plant species per 100 m2, 20% more than in similar‐sized areas beneath overstorey trees. Responses varied with life form; more herbaceous species occurred in recent and older overstorey openings than beneath overstorey trees. Total numbers of all species and of less abundant forb species were positively and linearly related to light transmitted to ground level. Those species responding to openings in the overstorey and positively associated with increased transmitted light levels were monocarpic and shortlived perennial forb and grass species with a seed bank in the soil. In addition, community structure, as reflected in species composition and abundances, appeared to vary with canopy condition.

Conclusions:Restoration involving ecologically sensitive removal of patches of overstorey pines in frequently burned pine savannas should benefit the ground cover and increase plant species biodiversity as a result of increased abundance of seed bank species.
Conservation management of Pinus palustris ecosystems from a landscape perspective
Authors: Kirkman L. Katherine , Mitchell Robert J.
Published: February 2009

Question: Do case studies from silvicultural and restoration studies and applied conservation management in second‐growth Pinus palustris stands provide unique insights for conservation models?

Methods: A review of management paradigms that conserve the high biological diversity and rare species, drawn from characteristics in both second‐growth and old‐growth stands, is presented for fire‐maintained Pinus palustris (longleaf pine) forests.

Results: A common assumption that old‐growth stands provide the primary information for the development of conservation management strategies de‐emphasizes lessons learned from second‐growth and restoration studies. Primary conservation management goals for the Pinus palustris ecosystem include the perpetual regeneration of the fire‐maintained forest and conservation of the characteristically high biological diversity and rare species. Several attributes, such as a sustained population of Picoides borealis (red‐cockaded woodpecker), Aristida stricta (wiregrass)‐dominated ground cover, and undisturbed upland‐wetland ecotones, can predict a diverse and ecologically functional ecosystem. Such indicators are linked to critical structural and functional features of the system and reflect previous land management histories that suggest sustainable approaches.

Conclusions: A traditional definition of ‘old‐growth’ relying on overstorey may be limited in describing important features of healthy, diverse Pinus palustris ecosystems. Some characteristics are significantly more important for maintenance of diversity than age of the trees and these features may be present in old‐ or second‐growth forests. We advocate that the management history, structural characteristics and landscape context of stands that harbour desirable conservation attributes (red‐cockaded woodpeckers, wiregrass, gopher tortoises and undisturbed upland‐wetland ecotones) can be used as indicators to identify important conservation and forest management principles.
Modelling responses of pine savannas to climate change and large‐scale disturbance
Authors: Beckage Brian , Gross Louis J. , Platt William J.
Published: February 2009

Global warming can potentially influence ecological communities through altered disturbance regimes in addition to increased temperatures. We investigate the response of pine savannas in the southeastern United States to global warming using a simple Lotka‐Volterra competition model together with predicted changes to fire and hurricane disturbance regimes with global climate change. In the southeastern United States, decreased frequency of both fires and hurricanes with global warming will shift pine savannas toward a forested state. A CO2 fertilization effect that increases the growth rate of tree populations will also push southeastern landscapes from open savannas towards closed forests. Transient dynamics associated with climate driven changes in vegetation will last on the order of decades to a century. In our model, the sensitivity of savannas to relative changes in the frequency of fire versus hurricanes is linearly dependent on the growth rate and mortality of trees in fire and hurricane disturbances.
Importance of sediment deposition and denitrification for nutrient retention in floodplain wetlands
Authors: Olde Venterink Harry , Vermaat Jan E. , Pronk Mario , Wiegman Frank , van der Lee Guda E.M. , van den Hoorn Martin W. , Higler L.W.G. (Bert) , Verhoeven Jos T.A.
Published: February 2009

Questions: Various floodplain communities may differ in their relative abilities to influence water quality through nutrient retention and denitrification. Our main questions were: (1) what is the importance of sediment deposition and denitrification for plant productivity and nutrient retention in floodplains; (2) will rehabilitation of natural floodplain communities (semi‐natural grassland, reedbed, woodland, pond) from agricultural grassland affect nutrient retention?

Location: Floodplains of two Rhine distributaries (rivers Ussel and Waal), The Netherlands.

Methods: Net sedimentation was measured using mats, denitrification in soil cores by acetylene inhibition and bio‐mass production by clipping above‐ground vegetation in winter and summer.

Results: Sediment deposition was a major source of N and P in all floodplain communities. Highest deposition rates were found where water velocity was reduced by vegetation structure (reedbeds) or by a drop in surface elevation (pond). Sediment deposition was not higher in woodlands than in grassland types. Denitrification rates were low in winter but significantly higher in summer. Highest denitrification rates were found in an agricultural grassland (winter and summer) and in the ponds (summer). Plant productivity and nutrient uptake were high in reedbeds, intermediate in agricultural grasslands, ponds and semi‐natural grasslands and very low in woodlands (only understorey). All wetlands were N‐limited, which could be explained by low N:P ratios in sediment.

Conclusions: Considering Rhine water quality: only substantial P‐retention is expected because, relative to the annual nutrient loads in the river, the floodplains are important sinks for P, but much less for N. Rehabilitation of agricultural grasslands into ponds or reedbeds will probably be more beneficial for downstream water quality (lower P‐concentrations) than into woodlands or semi‐natural grasslands.
Fen‐meadow succession in relation to spatial and temporal differences in hydrological and soil conditions
Authors: van der Hoek D. , Sýkora K.V.
Published: February 2009

Question: In fen meadows with Junco‐Molinion plant communities, falling groundwater levels may not lead to a boosted above‐ground biomass production if limitation of nutrients persists. Instead, depending on drainage intensity and micro‐topography, acidification may trigger a shift into drier and more nutrient‐poor plant communities.

Location: Nature reserve, central Netherlands, 5 m a.s.l.

Methods: Long‐term study (1988‐1997) in a fen meadow along a gradient in drainage intensity at different scales.

Results: Above‐ground biomass increased only slightly over ten years, despite a lower summer groundwater table. The accountable factors were probably a limited availability of nutrients (K in the higher well‐drained plots, P in the intermediate plots and N in the lower hardly drained plots), plus removal of hay.

Junco‐Molinion species increased in dry sites and Parvo‐caricetea species increased in wet sites, presumably primarily because of soil acidification occurring when rainwater becomes more influential than base‐rich groundwater. The extent of the shift in species composition depends primarily on the drainage intensity and secondarily on microtopography. Local hydrological measures have largely failed to restore wetter and more basic‐rich conditions.

Conclusions: Acidification and nutrient removal, leaching and immobilization resulted in the succession towards Junco‐Molinion at the cost of Calthion palustris elements. Lower in the gradient this change was reduced by the presence of buffered groundwater in slightly drained sites. To conserve the typical plant communities of the Junco‐Molinion to Calthion gradient in the long term, further acidification must be prevented, for example by inundation with base‐rich surface water.
Higher acidification rates in fens with phosphorus enrichment
Authors: Kooijman A.M. , Paulissen M.P.C.P.
Published: February 2009

Question: Why is bryophyte succession in eutrophicated fens faster than in natural fens?

Location: Mineral‐rich fens in The Netherlands and NW Europe.

Methods: Literature review on the ecology of four bryophyte species in various successional types as observed in Dutch fens.

Results: Bryophyte succession in eutrophicated fens from the brown moss Calliergonella cuspidata to Sphagnum squarrosum is much faster than in natural fens with species shifts from Scorpidium scorpioides to Sphagnum subnitens. Under P‐poor conditions, the brown moss stage is stabilized as long as mineral‐rich water is supplied. This is because S. scorpioides is tolerant of rainwater, is a strong competitor and can counteract acidification to some extent while S. subnitens is intolerant to groundwater and has low growth rates and low acidification capacity. In contrast, the Sphagnum stage is stable after rapid succession from rich‐fen mosses under P‐rich conditions. Calliergonella cuspidata has suboptimal growth in rainwater, possibly due to ammonium toxicity, while the high growth rates of S. squarrosum in nutrient‐rich and highly acidic groundwater allow early establishment and rapid expansion.

Conclusions: If measures to improve fen base status occur in environments of increased nutrient (P) availability, the management may not lead to the desired restoration of brown moss stages, but instead to rapid acidification by S. squarrosum.
Seed dispersal in fens
Authors: Middleton Beth , van Diggelen Rudy , Jensen Kai
Published: February 2009

Question: How does seed dispersal reduce fen isolation and contribute to biodiversity?

Location: European and North American fens.

Methods: This paper reviews the literature on seed dispersal to fens.

Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and reducing genetic exchange. Species in fragmented wetlands may have lower reproductive success, which can lead to biodiversity loss. While fens may have always been relatively isolated from each other, they have become increasingly fragmented in modern times within agricultural and urban landscapes in both Europe and North America. Dispersal by water, animals and wind has been hampered by changes related to development in landscapes surrounding fens. Because the seeds of certain species are long‐lived in the seed bank, frequent episodes of dispersal are not always necessary to maintain the biodiversity of fens. However, of particular concern to restoration is that some dominant species, such as the tussock sedge Carex stricta, may not disperse readily between fens.

Conclusions: Knowledge of seed dispersal can be used to maintain and restore the biodiversity of fens in fragmented landscapes. Given that development has fragmented landscapes and that this situation is not likely to change, the dispersal of seeds might be enhanced by moving hay or cattle from fens to damaged sites, or by reestablishing lost hydrological connections.
Sphagnum establishment on bare peat: The importance of climatic variability and Sphagnum species richness
Authors: Chirino C. , Campeau S. , Rochefort L.
Published: February 2009

Question: What is the relative ability of four species of Sphagnum (S. fuscum, S. rubellum, S. magellanicum and S. angustifolium) to establish on bare peat substratum in the field when re‐introduced as single or multi‐species re‐introductions and in relation to interannual variations in climate?

Location: Continental southeastern Canada.

Methods: Diaspores (fragments) of four Sphagnum species alone or in combination were re‐introduced onto residual peat surfaces and were monitored to follow the development of the moss carpet over four growing seasons. In order to compare results under a variety of climatic conditions, this whole experimental setting was repeated four times (trials), with a four‐year follow‐up for each trial.

Conclusions: The establishment rate of the moss carpet varied among years, in response to climatic variations between growing seasons. The relative success of different moss species and combinations of species, however, did not vary within or between trials. Thus, the species and combinations of species resulting in the highest short‐term or long‐term establishment rates remained the same for all trials, independent of the climatic conditions at the time of re‐introduction. Our results showed no link between the number of species in the diaspore mixture and successful establishment of the moss carpet. Yet successful regeneration was clearly influenced by the identity of species chosen for re‐introduction. S. fuscum, alone or in combination, was the species found to lead to the most extensive development of the moss carpet under the current test conditions.
Spatial heterogeneity in the determinants of woody plant invasion of lowland heath
Authors: Manning Peter , Putwain Philip D. , Webb Nigel R.
Published: February 2009

Questions: 1. What is the scale and extent of spatial variability in factors affecting Betula invasion of heaths? 2. How much effect does each factor have on within‐patch patterns of invasion? 3. How can this understanding aid in managing Betula invasions?

Location: Lowland heath of southern England.

Methods: Determinants of Betula (both B. pubescens and B. pendula) invasion: biomass density, necromass density, mean vegetation height, P‐availability, soil water content and total Betula seed bank density, were measured at two sites on a 5‐ha sampling grid. Spatial pattern was assessed using geostatistics. Contributions of each determinant to within‐site heterogeneity in predicted Betula seedling densities were estimated by varying variables over their full and interquartile ranges in a statistical model derived from experimental data.

Results: Salient spatial trends were revealed: strong autocorrelation over distances of < 50 m for soil factors and more extensive autocorrelation (0 to > 150 m) in vegetation variables and Betula seed bank densities. The latter resulted in single across‐site gradients, the former small, distinct patches. All patterns were overlain with variance that was present at distances of < 17.6 m. Variables displaying spatial pattern also accounted for within‐site heterogeneity in predicted Betula seedling densities but their relative contribution to this varied between sites.

Conclusions: Identifiable spatial autocorrelation in factors controlling patch‐scale invasion patterns allows managers to target invasion prone patches, potentially reducing management intensities. Furthermore, management effort may be optimised by spatially de‐coupling Betula seed from safe‐sites. This plan may adaptable to the management of other weeds and open‐land ecosystems.
Using life‐history traits to achieve a functional classification of habitats
Authors: Hérault Bruno , Honnay Olivier
Published: February 2009

Question: To establish a habitat classification based on functional group co‐occurrence that may help the drawing up of conservation plans.

Location: Riverine forest fragments in the Grand‐duché de Luxembourg, Europe.

Methods: Forest fragments were surveyed for their abundance of vascular plants. These were clustered into emergent groups according to 14 life‐traits related to plant dispersal, establishment and persistence. Forest fragments were classified according to similar distribution of the identified emergent groups. Environmental factors were related to the emergent group richness in each forest type using generalized linear models.

Results: Contrary to former species centred classifications, only two groups of forests, each with clearly different emergent group composition and conservation requirements, were detected: (1) swamp forests characterized by anemogamous perennials, annuals and hydrochorous perennials and (2) moist forests characterized by barochorous perennials, small geophytes and zoochorous phanerophytes. From a conservation point of view, priority should be given to large swamp forest with intact flooding regimes. This is in accordance with the high wind and water dispersal capacities of their typical emergent groups. For the moist forests, conservation priorities should be high forest connectivity and historical continuity since dispersal and establishment of their characteristic emergent groups are highly limited.

Conclusions: The described methodology, situated at an intermediate integration level between the individual species and whole community descriptors, takes advantage of both conservation plans built for single species and the synthetic power of broad ecological measures.
A study on genomic distribution and sequence features of human long inverted repeats reveals species‐specific intronic inverted repeats
Authors: Wang Yong , Leung Frederick C. C.
Published: February 2009

The inverted repeats present in a genome play dual roles. They can induce genomic instability and, on the other hand, regulate gene expression. In the present study, we report the distribution and sequence features of recombinogenic long inverted repeats (LIRs) that are capable of forming stable stem‐loops or palindromes within the human genome. A total of 2551 LIRs were identified, and 37% of them were located in long introns (largely > 10 kb) of genes. Their distribution appears to be random in introns and is not restrictive, even for regions near intron–exon boundaries. Almost half of them comprise TG/CA‐rich repeats, inversely arranged Alu repeats and MADE1 mariners. The remaining LIRs are mostly unique in their sequence features. Comparative studies of human, chimpanzee, rhesus monkey and mouse orthologous genes reveal that human genes have more recombinogenic LIRs than other orthologs, and over 80% are human‐specific. The human genes associated with the human‐specific LIRs are involved in the pathways of cell communication, development and the nervous system, as based on significantly over‐represented Gene Ontology terms. The functional pathways related to the development and functions of the nervous system are not enriched in chimpanzee and mouse orthologs. The findings of the present study provide insight into the role of intronic LIRs in gene regulation and primate speciation.
Functional Characterization of Nonadrenergic Noncholinergic Neurotransmitter Release via Endocannabinoids: An in Vitro Study in Rabbit Corpus Cavernosum
Authors: Vural Ismail M. , Ozturk Gokce S. , Sarioglu Yusuf
Published: February 2009

Introduction

Corporal smooth muscle relaxation is mediated mainly but not completely by nitric oxide. Endocannabinoids modulate the various neurotransmitter systems.

Aim

In the present study, a possible role of endocannabinoids on non-nitrergic nonadrenergic noncholinergic (NANC)-mediated relaxations was investigated.

Methods

In precontracted tissues, control electrical field stimulation (EFS)-induced NANC relaxation responses were obtained using varying frequencies of stimulation in the presence of L-arginine methyl ester (L-NAME), guanethidine, and atropine. To investigate the effects of cannabinoids on EFS-evoked non-nitrergic NANC relaxation responses, a similar experimental procedure was applied in the presence of cannabinoid receptor antagonists AM251 or AM630; vanilloid receptor antagonist capsazepine; or cannabinoid receptor agonists anandamide, arachidonyl-2-chloroethylamide (ACEA), or JHW015.

Main Outcome Measures

Effects of cannabinoid receptor antagonists and agonists on EFS-evoked non-nitrergic NANC relaxation responses.

Results

L-NAME abolished EFS-induced relaxation responses at lower frequencies (2–4 Hz) and inhibited the relaxation responses at higher frequencies (8–32 Hz). AM251 and AM630 either together or separately inhibited, whereas anandamide, ACEA, and JHW015 enhanced non-nitrergic NANC relaxation responses. Anandamide did not alter EFS-induced non-nitrergic NANC relaxations in the presence of AM251 and AM630. Capsazepine enhanced non-nitrergic NANC relaxation responses.

Conclusion

These results suggest that non-nitrergic NANC relaxations may be mediated partially by cannabinoid-like neuronal factors acting at both cannabinoid CB1 and cannabinoid CB2 receptors.
Losartan, an Angiotensin Type I Receptor, Restores Erectile Function by Downregulation of Cavernous Renin-Angiotensin System in Streptozocin-Induced Diabetic Rats
Authors: Yang Rong , Yang Bin , Wen Yanting , Fang Feng , Cui Souxi , Lin Guiting , Sun Zeyu , Wang Run , Dai Yutian
Published: February 2009

Introduction

The high incidence of erectile dysfunction (ED) in diabetes highlights the need for good treatment strategies. Recent evidence indicates that blockade of the angiotensin type I receptor (AT1) may reverse ED from various diseases.

Aim

To explore the role of cavernous renin-angiotensin system (RAS) in the pathogenesis of diabetic ED and the role of losartan in the treatment of diabetic ED.

Methods

The AT1 blocker (ARB) losartan (30 mg/kg/d) was administered to rats with streptozocin (65 mg/kg)-induced diabetes. Erectile function, cavernous structure, and tissue gene and protein expression of RAS in the corpora cavernosa were studied.

Main Outcome Measure

We sought to determine the changes of cavernous RAS in the condition of diabetes and after treatment with losartan.

Results

RAS components (angiotensinogen, [pro]renin receptor, angiotensin-converting enzyme [ACE], and AT1) were expressed in cavernosal tissue. In diabetic rats, RAS components were upregulated, resulting in the increased concentration of angiotensin II (Ang II) in the corpora. A positive feedback loop for Ang II formation in cavernosum was also identified, which could contribute to overactivity of cavernous RAS in diabetic rats. Administration of losartan blocked the effect of Ang II, downregulated the expression of AT1 and Ang II generated locally, and partially restored erectile function (losartan-treated group revealed an improved intracavernous pressure/mean systemic arterial pressure ratio as compared with the diabetic group (0.480 ± 0.031 vs. 0.329 ± 0.020, P < 0.01). However, losartan could not elevate the reduced smooth muscle/collagen ratio in diabetic rats.

Conclusions

The cavernous RAS plays a role in modulating erectile function in corpora cavernosa and is involved in the pathogenesis of diabetic ED. ARB can restore diabetic ED through downregulating cavernous RAS.
Potential of Adipose-Derived Stem Cells for Treatment of Erectile Dysfunction
Authors: Lin Guiting , Banie Lia , Ning Hongxiu , Bella Anthony J. , Lin Ching-Shwun , Lue Tom F.
Published: February 2009

Introduction

Adipose-derived stem cells (ADSCs) are a somatic stem cell population contained in fat tissue that possess the ability for self-renewal, differentiation into one or more phenotypes, and functional regeneration of damaged tissue, which may benefit the recovery of erectile function by using a stem cell-based therapy.

Aim

To review available evidence concerning ADSCs availability, differentiation into functional cells, and the potential of these cells for the treatment of erectile dysfunction (ED).

Methods

We examined the current data (from 1964 to 2008) associated with the definition, characterization, differentiation, and application of ADSCs, as well as other kinds of stem cells for the cell-based therapies of ED.

Main Outcome Measures

There is strong evidence supporting the concept that ADSCs may be a potential stem cell therapy source in treating ED.

Results

The ADSCs are paravascularly localized in the adipose tissue. Under specific induction medium conditions, these cells differentiated into neuron-like cells, smooth muscle cells, and endothelium in vitro. The insulin-like growth factor/insulin-like growth factor receptor (IGF/IGFR) pathway participates in neuronal differentiation while the fibroblast growth factor 2 (FGF2) pathway is involved in endothelium differentiation. In a preliminary in vivo experiment, the ADSCs functionally recovered the damaged erectile function. However, the underlying mechanism needs to be further examined.

Conclusion

The ADSCs are a potential source for stem cell-based therapies, which imply the possibility of an effective clinical therapy for ED in the near future.
Clinical recommendations for the use of lapatinib ditosylate plus capecitabine for patients with advanced or metastatic HER2‐positive breast cancer
Authors: SNYDER Raymond D , BOYLE Frances M , CHAN Arlene , CRAFT Paul S , BOER Richard DE , MAINWARING Paul N , McCARTHY Nicole J , WILCKEN Nicholas R
Published: February 2009

Primary and acquired resistance to trastuzumab pose a therapeutic challenge when treating patients with HER2 (erbB‐2)‐positive locally advanced or metastatic breast cancer (MBC). The recent introduction of lapatinib (Tykerb/Tyverb, GlaxoSmithKline, Brentford, UK) provides a new management option for such patients. A prospective, randomized phase III clinical trial has confirmed that lapatinib in combination with capecitabine extends time to progressive disease in HER2‐positive MBC, compared with capecitabine alone in patients with disease progression despite prior anthracycline, taxane and trastuzumab therapy. Preliminary data also indicate that lapatinib may exert a beneficial effect on brain metastases, a common sanctuary site for HER2‐positive breast cancer following trastuzumab treatment. The tolerability of lapatinib is commensurate with that of other erbB family tyrosine kinase inhibitors and no significant new adverse events have emerged following its introduction into clinical practice. In particular, no additive cardiotoxicity has been observed when lapatinib is prescribed after trastuzumab therapy. Based on the published literature and supplemented by clinical experience, this article provides practical management recommendations for the use of lapatinib plus capecitabine in patients with MBC. Issues addressed include patient selection, baseline evaluation and monitoring for clinical benefit. The minimization and management of adverse events is also discussed in detail, particularly the dermatological and gastrointestinal effects, which are the most clinically significant side‐effects of lapatinib therapy. Further recommendations cover the minimization of drug interactions, anticipated dosing alterations and the optimal employment of oral anticancer regimens.
Examining Teacher Grades Using Rasch Measurement Theory
Authors: Randall Jennifer , Engelhard George
Published: February 2009

In this study, we present an approach to questionnaire design within educational research based on Guttman's mapping sentences and Many‐Facet Rasch Measurement Theory. We designed a 54‐item questionnaire using Guttman's mapping sentences to examine the grading practices of teachers. Each item in the questionnaire represented a unique student scenario that was graded by teachers. Three focus groups of elementary (N = 5), middle (N = 4), and high school (N = 2) teachers examined the scenarios for clarity, comprehensiveness, and ease of understanding. Based on the suggestions of the focus groups, the revised questionnaires were completed by 516 public school teachers located in a major metropolitan county in the Southeast. The grades assigned by the teachers to the scenarios were analyzed using the FACETS computer program. The results of the analyses suggest that teachers primarily assign grades on the basis of student achievement as expected, although for some teachers other facets (ability, behavior, and effort) may play a role in final grade assignment.