New Zealand machair vegetation

Abstract. Machair vegetation is reported for the first time from New Zealand. The habitat is similar to that of British machairs in climate, topography and generally in soil. pH and CaCO₃ content are much lower through most of the sequence, though this difference may partly reflect the greater disturbance of British machair. Sea machair is present, predominantly comprising native species. This grades into machair proper, which contains many species found also in British machair. The machair includes Ammophila-occupied hillocks, a feature typical of British machair. Machair marsh is also present.     

The UK Machair Habitat Action Plan: Progress and problems

Summary

Machair is a complex dune grassland habitat confined to Scotland and Ireland. With two-thirds of the world area of machair in Scotland, the UK has a special responsibility for this resource, and the UK Machair Habitat Action Plan identifies a range of realistic management targets and actions aimed at protecting and enhancing the habitat.

Machair's conservation importance is substantially reliant on active, traditional management, but quantitative and location-based information on management is rarely available, and this will have an impact on any numerical targets in the Plan. Though progress has been made on many of the actions, further measurable progress will very much depend, not only on improvements in the information base, but also in the understanding of relationships between land use and biodiversity.

Progress to date on actions and targets is evaluated, and problems are identified.     

Agriculture,weeds and the western isles machair

Summary

The Western Isles machair has supported agriculture for 5,000 years, but its future suitability for this purpose is far from certain. Marine transgression and changes in agricultural practice have profound effects on this fragile environment, but the dynamics of cause and effect are not documented. A constructive policy for management and conservation of the machair must be based on an intimate knowledge of the environment, gained in detailed, multidisciplinary studies involving several years of close monitoring. The project described in this paper aims to define, in geomorphological and vegetational terms, the responses of the machair to changing patterns of agriculture, climatic conditions and rising sea levels.     

Plant species and community responses to sand burial on the machair of the Outer Hebrides,Scotland

Question: Is there a critical depth of burial by sand beyond which species and communities fail to recover, and does repeated incremental burial have a greater impact than a single large deposition? Location: The machair on the calcareous sand dunes on South Uist, in the Outer Hebrides of Scotland, UK. Methods: Eight turves were collected from each of four machair sub‐community types. After acclimatization in an unheated polythene tunnel, they were buried with sterilized machair shell sand, either by one single burial to 5 cm or by five applications of 1 cm of sand at approximately seven‐week intervals. Species response was recorded on five occasions. Results: Within machair sub‐communities, burial by sand reduced the abundance (local rooted frequency) of plants more than it reduced species richness. Intermittent burial was more damaging than a single burial event. Those species with the highest pre‐burial frequencies tended to dominate recovery in the sub‐community as a whole. Species occurring across all four sub‐community types exhibited varying responses to community burial between the differing types. Samples from slack sub‐communities had distinctly different response characteristics from those of foredunes and unploughed and three‐year fallow dune grassland. Conclusions: The perennial life‐form of many machair species has been evolutionarily selected for and dominates throughout the machair habitat. Account needs to be taken of competitive interaction between species in relation to burial response. The results of the investigation show that the hypotheses of Gilbertson et al. and Kent et al. on ‘machair stratification’ require refinement in that frequency of shallow burial can be as important as overall burial depth.     

Polymorphism for cyanogenesis in Lotus corniculatus on links and machair in Orkney and the outer hebrides

Summary

A survey of the cyanogenic polymorphism in Lotus corniculatus L. at Birsay Links, Orkney, showed the relative frequency of the cyanogenic phenotype to be low (7–8 per cent) on the dry soils towards the centre of the links but to rise steadily towards the borders where soil moisture content was high. At other links and machair sites in Orkney and the Outer Hebrides the cyanogenic phenotype never fell below a relative frequency of 83 per cent although moisture content was usually no higher than that recorded for the driest soils at Birsay. Several possible explanations are presented for this difference.     

The conservation and management of machair

Summary

Machair is a landform located on the north and west coasts of Scotland and Ireland. This paper describes the habitat components that constitute a machair system and the complex interrelationship of biotic and abiotic factors that have created this landscape. A total landscape approach is essential for effective management.     

How does dune morphology shape coastal EC habitats occurrence? A remote sensing approach using airborne LiDAR on the Mediterranean coast

We examined the relationship between coastal habitats (sensu European Union Habitats Directive) and local dune morphology along a Mediterranean coastal dune system by integrating field collected vegetation data and remotely sensed imagery. Specifically, we described the morphological profile of each EC habitat based on the morphological variables that are most likely to affect their occurrence, including elevation, slope, curvature, northness, eastness and sea distance. In addition, we assessed the role and strength of each morphological variable in determining the occurrence of EC habitats.We used 394 random vegetation plots representative of six EC habitats (Habitat 1210: “Annual vegetation of drift lines”; Habitat 2110: “Embryonic shifting dunes”; Habitat 2120: “Shifting dunes along the shoreline with Ammophila arenaria”; Habitat 2210 and 2230: “Crucianellion maritimae fixed beach dunes” and “Malcolmietalia dune grasslands”; Habitat 2250: “Coastal dunes with Juniperus spp.”; Habitat 2260: “Cisto-Lavanduletalia dune sclerophyllous scrubs”) found along the Tyrrhenian coast of central Italy. We derived each morphological variable from a DTM (Digital Terrain Model) obtained from 2-m resolution LiDAR (Light Detection And Range) images. The mean value of each variable was calculated at different spatial scales using buffer areas of increasing radius (2 m, 4 m, 8 m) around each vegetation plot. Mean morphological values for each EC habitat were compared using Kruskal-Wallis rank test. The role and strength of the relationship between habitat type and the morphological variables were assessed using Generalized Linear Models.EC habitats occur differentially across dune morphology, and the role and strength of each morphological variable define habitat specificity. Dune elevation and sea distance were determined to be the key factors in shaping EC habitat occurrence along this section of the Mediterranean coast. Identification of the close relationship between habitat type and morphological variables deriving from airborne LiDAR imagery points to the high potential of such remote sensing tool for analyzing and monitoring the integrity of coastal dune ecosystems. As airborne LiDAR enables the rapid collection of extremely accurate topographic data over large areas, it also offers useful information for the management of these threatened and fragile ecosystems.     

Roll of the Botanical Society of Edinburgh

Summary

The succession of vascular plants and lichens along a 131m transect, representing 70 – 80 years accretion to a sand-dune system, was studied at Tentsmuir Point National Nature Reserve, Fife. Its flora is compared to other dune areas and the reasons why some such areas are lichen-rich and others lichen-poor are discussed.     

Intégration des critères métaboliques de la TEP au 18FDG pour le choix des lésions cibles en imagerie onco-hématologique

IntroductionMalignant lymphoma is a heterogeneous and widespread disease. The morphological response assessment is currently based on the choice of target lesions at baseline, defined by size criteria on enhanced CT (eCT). FDG PET/CT is now commonly used at staging and the aim of this study was to evaluate the relevance of using metabolic criteria rather than size criteria to define the target lesions.Patients and methodsFifty-nine patients with aggressive lymphoma were retrospectively included. Target lesions were chosen by two radiologists on eCT and by two nuclear physicians on PET/CT. Response assessment, based on the sum of the products of the greatest diameters of up to six target lesions chosen either by size or metabolic criteria, was computed and compared to a clinical gold standard (GS) for each patient. Interobserver agreement and comparison to the GS were assessed with kappa (κ) and intraclass correlation (ICC) statistics.ResultsThe spatial distribution of target nodal areas was equivalent among eCT and PET/CT readers with a maximum of target lesions in cervical and mediastinal areas. Choosing with PET/CT led to significant heterogeneity in the size of target lesions when compared with eCT alone (P = 0.03). Interobserver agreement for quantifying the response rate was equivalent in both groups. However, there was a greater correlation to the response of the GS when using PET/CT to target the patient (κ = 0.64 vs. 0.47) and an increased rate of complete responses.ConclusionsMetabolic criteria can replace current size criteria to define target lesions on FDG PET/CT. The morphological response rate appears accurate with an increased rate of complete responses after therapy and a better correlation to the haematological standard of reference.     

Changes in the breeding wader populations of the machair of the Western Isles,Scotland, between 2000 and 2007

Capsule The machair of the Uists continues to support one of the most important assemblages of breeding waders in Europe, but there have been major variations in population change across the archipelago, the causes of which are poorly understood.     

Proposte Per La Tutela Di Alcune Aree,Di Particolare Interesse Geobotanico,Nel Parco Nazionale Del Circeo

Abstract

Proposals for the protection of some areas, of particular geobotanical interest, in the Circeo National Park. — The Circeo National Park is located south of Rome in the province of Latina. Its area is about 7.445 hectares. It is characterised by three neatly differentiated environments: the calcareous massive of Mt. Circeo, the State Forest of Sabaudia and the littoral dune. The Park's vegetation is threatened by numerous dangers. These are caused by the progressive building expansion in act on Mt. Circeo as well as on the littoral dune; by the introduction of various alien species, particularly in parks and gardens, which contaminate the local flora; by the afflux of picnickers who converge mainly on the dune; by pasture allowed in the State Forest; by the building of a road which cuts in half the southern slope of Mt. Circeo; by the exploitation of a stone-mine on Mt. Circeo. In order to preserve, at least partially, the vegetation from such threats, the Author proposes that five areas should be fenced and declared « Integral protected area ». Three areas are included in the State Forest, one on Mt. Circeo and the other on the dune. The total area is about 583 hectares. These areas comprise the most interesting aspects of the natural vegetation of the Park and groups of introduced arboreal plants (Pinus and Eucalyptus) of particular technical interest. The establishment of these reserves will have a scientific as well as an experimental aim. In such reserves all human activities should be prohibited with the exception of some cultural interventions on the introduced species. The areas of the State Forest include a nucleus of forest of Quercus cerris; a mesohygrophilous cenosis in which Quercus pedunculata predominate, with Alnus glutinosa and Fraxinus oxycarpa; a scrubby heath with Erica arborea, Erica scoparia and Myrtus communis, with specimen of Quercus pseudo-suber; a small prairie abundant with annual species; a plot of Eucaliptus grandis. The area of Mt. Circeo include large patches of maquis and wood-maquis (macchia and macchia-foresta), alophilous cenosis, rocky plant communities, and other facies of Mediterranean vegetation with specimen of Chamaerops humilis. The area of the dune is variegated with patches of maquis on sandy soil, swamp cenosis, fragments of mesohygrophilous vegetation, and small nuclei of introduced species. The Author suggests some executive norms in order to provide full protection of the proposed areas as well as the environment of the Park. He favours a solution by which the State should acquire both areas of the dune and of the Mt. Circeo, and also suggests particular bonds for the defense of the natural vegetation of the State Forest. In the forest, in fact, no plants of Quercus pedunculata, Quercus suber, Quercus ilex, Quercus pseudo-suber, Cytisus laburnum, Acer campestre and Tilia europaea should be utilised. Finally the Author advises against the introduction in the forest of species alien to the local flora and the destruction, except in particular cases, of the underwood.     

State of Scots pine (Pinus sylvestris L.) under nutrient and water deficit on coastal dunes of the Baltic Sea

The aim of the present study was to assess the ecophysiological state of Scots pine (Pinus sylvestris L.) growing at different heights on one of the typical coastal sand dunes in the dune field situated in southwestern Estonia. Dependence of the anatomical structure, morphological parameters, nutrients accumulation and biochemical characteristics of needles on the location of the site on the dune and on the concentration of nutrients in soil and in needle tissues was established. Correlation analysis revealed the dependence of chlorophyll a on the concentration of N and Mg in soil as well as in needles. The mesophyll area and chlorophyll concentration in needles were smallest on the top of the dune. The proportion of epidermis in the total needle cross-section area from the top was a little larger than in the needles from the bottom; the epicuticular wax layer on needles decreased towards the top. The length of needles and shoots was the lowest on the top of the dune, where the growth substrate contains notably less nutrients and water than needed for optimum growth of trees. The t test showed statistically significant larger average tree-ring width of the pines growing at the bottom. The pines on the top and at the bottom of the dune were not sensitive to temperature conditions. The radial growth of pines on the top of the dune was positively correlated with the total precipitation of the previous year.     

Nitrogen translocation in a clonal dune perennial,Hydrocotyle bonariensis

Summary Hydrocotyle bonariensis, a common rhizomatous perennial of coastal North Carolina, forms extensive clones in dune systems characterized by a patchy nitrogen distribution. An experiment was conducted in which Hydrocotyle clones were grown across artificially created soil nitrogen gradients to determine: (1) the effect of soil nitrogen availability and nitrogen translocation on clonal structure and (2) the costs versus benefits of nitrogen translocation as measured by sexual and clonal reproduction. Acropetal translocation of nitrogen resulted in highly significant benefits to clones growing from areas of high N to areas of low N. Limited basipetal translocation was also demonstrated. Hydrocotyle ramets responded to increased nitrogen availability, from either intraclonal translocation or immediate uptake from the soil, by producing branches. Nitrogen level, however, had no effect on internode distances. Clonal integration of nitrogen, in tandem with a plastic morphology, allow Hydrocotyle clones to expand across a nitrogen-limited dune environment and to locally exploit nitrogen patches when they are encountered.     

Fluctuating deposition of ocean water drives plant function on coastal sand dunes

Sea‐level rise will alter the hydrology of terrestrial coastal ecosystems. As such, it becomes increasingly important to decipher the present role of ocean water in coastal ecosystems in order to assess the coming effects of sea‐level rise scenarios. Sand dunes occur at the interface of land and sea. Traditionally, they are conceived as freshwater environments with rain and ground water as the only water sources available to vegetation. This study investigates the possibility of ocean water influx to dune soils and its effect on the physiology of sand dune vegetation. Stable isotopes are used to trace the path of ocean water from the soil to the vegetation. Soil salinity, water content and δ¹⁸O values are measured concurrently with stem water and leaf tissue of eight species during the wet and dry season and from areas proximal and distal to the ocean. Our results indicate the dune ecosystem is a mixed freshwater and marine water system characterized by oceanic influence on dune hydrology that is spatially heterogeneous and fluctuates temporally. Ocean water influx to soil occurs via salt spray in areas 5–12 m from the ocean during dry season. Accordingly, vegetation nearest to the sea demonstrate a plastic response to ocean water deposition including elevated integrated water use efficiency (δ¹³C_leaf) and uptake of ocean water that comprised up to 52% of xylem water. We suggest physiological plasticity in response to periodic ocean water influx may be a functional characteristic common to species on the leading edge of diverse coastal habitats and an important feature that should be included in modeling coastal ecosystems. Rising sea level would likely cause a repercussive landward shift of dune species in response to encroaching maritime influences. However, human development would restrict this process, potentially causing the demise of dune systems and the protection from land erosion they provide.     

Effect of cereal harvesting method on a recent population decline of Corn Buntings Emberiza calandra on the Western Isles of Scotland

Capsule Population decline since 1995 is associated with the harvesting of cereals as arable silage.

Aim To survey Corn Bunting populations on the Western Isles and test whether population changes since 1995 are associated with change in cereal harvesting methods.

Methods Twelve areas of machair on the Uists and Benbecula were re-surveyed in 2002, after previous surveys in 1983 and 1995. These and other areas of suitable habitat on these islands, plus Berneray, Baleshare, Vallay, Barra and Vatersay, were surveyed in 2003–05 to provide a breeding population estimate for the Western Isles. Cereal strips in the 12 core survey areas were mapped in 2002 and the timing and method of harvesting of each was recorded. Cattle-feeding stands in 24 crofting townships were visited in March 2003 to record the type of fodder available, measure grain abundance and ripeness in fodder samples, and record foraging Corn Buntings. Experimental trials tested whether Corn Buntings selected fodder with riper grain.

Results The Western Isles Corn Bunting population was estimated at 117 occupied territories in 2005, a decline of 17% since 2002/03, and of at least 62% since 1995. Population decline was greater in areas with higher proportions of the cereal area harvested as arable silage. Arable silage contained fewer and less-ripe grains than traditionally harvested cereal, and was less likely to attract feeding Corn Buntings. Corn Buntings preferred to feed on silage containing riper grain.

Conclusions The remaining Corn Bunting population of the Western Isles is declining rapidly, probably because of reduction in winter grain supply caused by change from traditional reaper-binder harvesting and stacking of fully ripe cereals to harvesting the crop as unripe or partially ripe arable silage. Management change to restore a supply of ripe grain over winter is likely to be essential if this population decline is to be halted and reversed.     

Understanding the influence of urbanization on invasibility: <Emphasis Type="Italic">Carpobrotus edulis</Emphasis> as an exemplar

Coastal dune areas are valuable ecosystems, generally impacted by habitat destruction and invasive alien species. In this study, we assessed how human disturbance and invasion by Carpobrotus edulis impact the soils and the establishment of native flora in the north-western coastal regions of Spain. We compared soil characteristics (pH, conductivity, water content, nutrients and enzymatic activities) and native plant as well as C. edulis fitness correlates (germination and early growth) between uninvaded and invaded soils from urban and natural coastal dune areas. We found that human disturbance impacts coastal soils by increasing organic matter and water content, modifying soil nutrients and cycles, and reducing the pH in urban soils. The presence of invasive C. edulis further increases these impacts. These changes in soil characteristics allow for the establishment of the native, but ruderal, Scolymus hispanicus and non-native C. edulis, both of which are not adapted to the typically limiting conditions of coastal dunes. In some instances, the coastal dune endemic, Malcolmia littorea, showed no fitness effects in response to urbanization or the presence of C. edulis. These results suggest that human disturbed coastal areas might be more easily invaded than natural areas. More broadly, our findings of differential responses of different native species to disturbance and invasion, illustrate the need for multi-taxon approaches when assessing the impacts of invasive species.     

A conceptual model of coastal dune ecology synthesizing spatial gradients of vegetation, soil, and geomorphology

Patterns of coastal dune vegetation are closely related with soil conditions controlled by geomorphic forms and processes. This study developed a conceptual model integrating these relationships in a spatially explicit manner. A rectangle of 180 × 280 m containing 126 grids of 20 × 20 m was established in the Sindu coastal dunefield in west Korean Peninsula. Sampling from each grid determined 11 soil properties and identified percent cover of 21 woody and herbaceous plant species. Digital elevation models were generated by topographic survey and used to derive eight topographic parameters. Redundancy analysis and canonical correspondence analysis examined the effect of geomorphic factors on edaphic characteristics and the edaphic influence on spatial distribution of vegetation, respectively. The spatial pattern of soil properties and plant species were inferred from spatial interpolation techniques. In the foredune area, distance from the coastline was a significant indicator of soil nutrients derived from the marine sources by aeolian processes. This favored the dominance by Elymus mollis. Moisture-tolerant species (e.g., Calamagrostis epigeios) had high cover in the acidic soils of dune slacks, which covaried with wetness index, an indirect measure of the depth to the freshwater table. Vegetation–soil interactions (e.g., nitrogen fixation by legumes) were important in secondary dune areas, with topographic effects less significant. Vegetation, soil, and geomorphic factors are closely connected in a causal chain across a whole dune area. Our model thus addresses the importance of integrating foredune, dune slack, and secondary dune into one continuous system.     

Factors influencing the natural regeneration of the pioneering shrub Calligonum mongolicum in sand dune stabilization plantations in arid deserts of northwest China

Calligonum mongolicum is a successful pioneer shrub to combat desertification, which is widely used for vegetation restoration in the desert regions of northwest China. In order to reveal the limitations to natural regeneration of C. mongolicum by asexual and sexual reproduction, following the process of sand dune stabilization, we assessed clonal shoots, seedling emergence, soil seed bank density, and soil physical characteristics in mobile and stabilized sand dunes. Controlled field and pot experiments were also conducted to assess germination and seedling emergence in different dune soil types and seed burial depths. The population density of mature C. mongolicum was significantly different after sand dune stabilization. Juvenile density of C. mongolicm was much lower in stabilized sand dunes than mobile sand dune. There was no significant difference in soil seed bank density at three soil depths between mobile and stabilized sand dunes, while the emergence of seedlings in stabilized dunes was much lower than emergence in mobile dunes. There was no clonal propagation found in stabilized dunes, and very few C. mongolicum seedlings were established on stabilized sand dunes. Soil clay and silt content, air‐filled porosity, and soil surface compaction were significantly changed from mobile sand dune to stabilized dunes. Seedling emergence of C. mongolicm was highly dependent on soil physical condition. These results indicated that changes in soil physical condition limited clonal propagation and seedling emergence of C. mongolicum in stabilized sand dunes. Seed bank density was not a limiting factor; however, poor seedling establishment limited C. mongolicum's further natural regeneration in stabilized sand dunes. Therefore, clonal propagation may be the most important mode for population expansion in mobile sand dunes. As a pioneer species C. mongolicum is well adapted to propagate in mobile sand dune conditions, it appears unlikely to survive naturally in stabilized sand dune plantations.