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‘Alpine grazing reduces blazing’ is a widely and strongly held view concerning the effects of livestock grazing on fuels, and therefore fire behaviour and impact, in Australia's high country landscapes. As a test of this hypothesis, we examined the patterns of burning across the alpine (treeless) landscapes of the Bogong High Plains in Victoria, following the extensive fires of January 2003. Data were collected from multiple transects, each 3–5 km long, with survey points located randomly at either 50, 200 or 500 m intervals. The transects traversed the major regions of the Bogong High Plains, both grazed and ungrazed. At each point, we recorded whether the point was burnt or unburnt, the vegetation type (closed-heath, open-heath, grassland or herbfield), the estimated prefire shrub cover, slope, aspect, and a GPS location. At burnt heathland sites, we recorded the minimum twig diameter (an a posteriori measure of fire severity) in a sample of common shrubs. In total, there were 108 km of transect lines, 419 survey points and 4050 twig measurements, with sample points equally distributed across grazed and ungrazed country. The occurrence of fire (i.e. burnt or unburnt) in grazed and ungrazed areas was analysed by logistic regression; the variation in twig diameters byanova. Approximately half of all points were burnt. There was no statistically significant difference between grazed and ungrazed areas in the proportion of points burnt. Fire occurrence was determined primarily by vegetation type, with the proportion burnt being 0.87 for closed-heath, 0.59 for open-heath, and 0.13 for grassland and all snow-patch herbfield points unburnt. In both closed-heath and open-heath, grazing did not significantly lower the severity of fire, as measured by the diameter of burnt twigs. We interpret the lack of a grazing effect in terms of shrub dynamics (little or no grazing effect on long-term cover of taller shrubs), diet and behaviour of cattle (herbs and dwarf shrubs eaten; tall shrubs not eaten and closed-heath vegetation generally avoided), and fuel flammability (shrubs more flammable than grass). Whatever effects livestock grazing may have on vegetation cover, and therefore fuels in alpine landscapes, they are likely to be highly localized, with such effects unlikely to translate into landscape-scale reduction of fire occurrence or severity. The use of livestock grazing in Australian alpine environments as a fire abatement practice is not justified on scientific grounds. [ABSTRACT FROM AUTHOR]

The open coastal heathlands in Norway have changed character in recent decades, mainly because traditional practices such as burning, cutting and grazing have been abandoned or reduced. In a project aimed at increasing our knowledge of woodland regeneration in oceanic boreal heathlands, an area on the island of Kalvøya in the archipelago of Vikna on the extreme outer coast of central Norway has been studied. Kalvøya has calcareous bedrock; rich heath, rich fens and low-herb woodland cover 20% of the island. Large parts are paludified, and wet heath and mire vegetation cover 60%. The island has not been inhabited, but it was used for summer farming in the latter part of the 19th century and later for stock grazing. The woodland and scrub were mapped using aerial photographs from 1961 and 1981, and by fieldwork in 2001. Vegetation changes were analyzed using GIS techniques. Woodland and scrub increased from 3.0% in 1961, to 4.3% in 1981, to 11.6% in 2001. Betula pubescens is the commonest woody species. The oldest trees are 150 to 175 years old, growing in the most heavily wooded area, far away from the summer farm. In addition to human impact (summer farm, grazing pressure), the geology, terrain (degree of exposure), and climatic factors are important for woodland colonisation and distribution. [ABSTRACT FROM AUTHOR]

This paper describes how second/third year undergraduates with little prior botanical knowledge, attending a one-week field course in Western Scotland, were enabled to complete within one day an intensive phytosociological exercise. They showed that two stands of heathland vegetation were objectively different through identification of plants, estimation of species abundance, and ordination analysis. This gave them the knowledge and confidence to design and undertake a subsequent project in field botany. [ABSTRACT FROM AUTHOR]

Tropical cyclonic storm systems can have profound impacts on coastal plant communities both through direct mechanical damage and indirect factors, such as flooding or salt spray. Storms with high wind and low rainfall are especially likely to cause high salt spray accumulation on plants growing in close proximity to the ocean. I measured salt spray accumulation on a common coastal heathland plant species, Myrica pensylvanica, during normal growing-season conditions and following Tropical Storm Floyd. At both sampling times, salt spray accumulation was highest in areas closest to the ocean and salt decreased as distance from the ocean increased. Salt spray accumulation on leaves following the tropical storm was twice the salt spray accumulation during normal growing-season conditions. I also found higher necrosis on leaves following the tropical storm, particularly at distances farther from the ocean. These results suggest that even minor cyclonic storms could have an impact on coastal plants in New England through salt spray damage. [ABSTRACT FROM AUTHOR]

Abstract: The large losses of heathland area since the end of the 18th century can be expected to have resulted in the decline or even extinction of many characteristic heathland species. Historical data on plant species distribution patterns can provide valuable information in this context. Therefore, the aims of this research are to study how the loss of heathland area has changed the presence of heathland and forest plant species in north-western Belgium using historical plant distribution data, and to test whether the heathland flora shows an extinction debt. Furthermore, plant traits determining extinction sensitivity are investigated. Our results revealed that, despite the dramatic reduction of heathland area (more than 99% of heathland was destroyed over a 230-year period), the loss of heathland species is relatively limited (11%) and is comparable with that of forest species (11%). Heathland species that have a long-term persistent seed bank or can propagate vegetatively are least sensitive to extinction. For forest species, on the other hand, growth form is the key determinant for extinction sensitivity. Long-lived woody species have a greater chance of persisting. The relatively low extinction numbers probably represent an extinction debt and the full effects of habitat loss may not have been fully manifested yet. Consequently, future extinctions are expected to occur unless environmental conditions are improved. Therefore, heathland restoration and prevention of further heathland area losses is required. [Copyright &y& Elsevier]

Abstract Extant representatives of the ancient crustacean family Anaspididae are restricted to the island State of Tasmania, Australia. Allanaspides hickmani and Allanaspides helonomus were first described in the early 1970s from surface pools in buttongrass moorland in two adjacent watersheds in south-west Tasmania. Both of these catchments have since been inundated for hydroelectric power generation (Lake Gordon and Serpentine Impoundments). Surveys indicate that both species persist in a small number of highly fragmented populations on the margins of the two impoundments. A. hickmani and A. helonomus have extant Areas of Occupancy of c. 21 and 54 km2, respectively. We estimate that inundation resulted in the loss of 85–94% of the original range of A. hickmani and c. 78% of the original range of A. helonomus. Under IUCN Red List guidelines and National threatened species legislation A. hickmani but not A. helonomus may qualify for listing as Vulnerable (Area of Occupancy <20 km2). At the present time only A. hickmani is listed as Rare under Tasmanian (State) threatened species legislation but A. helonomus merits the same listing under State legislation. Global warming appears to pose the most significant potential threat to Allanaspides species. [ABSTRACT FROM AUTHOR]

North American coastal sandplain heathlands are unique in species composition and vegetation, but the extent to which edaphic factors influence the structure of these communities is currently debated. It was hypothesized that salt spray and edaphic factors maintain the dwarf stature and community composition of heathlands by limiting plant growth and excluding competitively dominant woody species close to the ocean. Field surveys were carried out to investigate the spatial patterns of salt spray accumulation, soil salt and soil moisture. High salt spray correlated significantly with increased leaf necrosis and water stress in Myrica pensylvanica and with decreased plant height. Plant community composition changed across a salt spray and soil gradient, as well. Distinctive sub-communities were identified that separated according to soil salt and soil moisture but salt spray was the main factor affecting sites occupied only by heathland vegetation. Results from this study suggest that salt spray suppresses the growth of heathland plants in close proximity to the ocean, and therefore maintains the low stature in these dwarf shrublands. This research also demonstrates that the physical environment influences the community structure in heathlands, particularly by limiting tree species from growing in high salt spray, low water availability sites. [ABSTRACT FROM AUTHOR]

1. Atmospheric nutrient deposition has contributed to widespread changes in heathlands throughout Europe. As a consequence, management is now being considered as a potential tool with which to compensate for increased nutrient loads. Currently, only limited information is available on the extent to which management measures could compensate for atmospheric nutrient deposition. We hypothesized that low-intensity management measures are not sufficient to counterbalance current nutrient inputs, particularly of nitrogen (N). 2. In order to improve heathland management schemes, we evaluated the effectiveness of different management measures in reducing the impact of ongoing atmospheric nutrient loads. We compared the effects of mowing, prescribed burning (low-intensity management) and sod-cutting (high-intensity management) on heathland nutrient budgets [N, calcium (Ca), potassium (K), magnesium (Mg) and phosphorus (P)] in the Lueneburg Heath nature reserve (north-west Germany). Nutrient balances were calculated by analysing the present-day input, the output as a result of the removal of biomass/humus horizons, and changes in leaching rates. 3. Nutrient losses by increased leaching following management measures were negligible compared with nutrient losses caused by the removal of above-ground biomass or humus horizons. The total quantities of nutrients removed by sod-cutting were equivalent to between 37 and 176 years of atmospheric input (for N, 89 years). 4. In contrast, the quantities of N removed by mowing and prescribed burning were equivalent to only 5 years of atmospheric input. Thus, heathlands subjected to such treatments will accumulate N in the long term. In addition, output–input ratios for phosphorus (P) exceeded those for N in the mowing and sod-cutting experiments. It is therefore likely that heathlands currently (co-) limited by N will shift to being more P-limited in the long term. This will promote species that are well adapted to P-limited sites (e.g. Molinia caerulea). 5. Synthesis and applications. This study shows that low-intensity management cannot compensate for atmospheric N loads in the long term. Consequently, high-intensity management measures are an indispensable tool in preserving a long-term balanced N budget in heathlands. In order to maintain a diverse structure, managers need to combine low- and high-intensity management measures. Prescribed burning proved to be the best means of avoiding an increasing P shortage, because this measure causes very low P outputs. [ABSTRACT FROM AUTHOR]

A description and analysis of the vascular plant composition of heathlands in the Annapolis valley were undertaken to provide a basis for biodiversity preservation within a system of protected sites. Species presence and abundance were recorded at 23 remnant sites identified using topographic maps, air photos, and Nova Scotia Department of Natural Resources records. A total of 126 species was recorded, of which 94 were native and 31 introduced. The Annapolis heathland remnants are strongly dominated by Corema conradii with Comptonia peregrina, Vaccinium angustifolium and Pteridium aquilinum var. lathtsculum. A number of species, including Solidago bicolor, Carex tonsa var. rugosperma, Dichanthelium depauperatum, Lechea intermedia, Melampyrum lineare, and Rubus hispidus, were characteristic of heathland remnants, although they usually contributed little to the total cover. The most frequent alien species were Hieracium pilosella and Festucafiliformis, but Pinus sylvestris, present at 7 of 18 sites, appeared to have the greatest impact in displacing native species. Species listed as at risk and sensitive in Nova Scotia, including Helianthemun canadense, Hudsonia ericoides and Viola sagittata var. ovata, occur in open disturbed sand in the Corema heathlands. Distinctive patterns of variation occur in several species and variation in crop relatives is noted with particular reference to the genera Rubus (blackberries), Amelanchier (Juneberries, Saskatoon) and Vaccinium (Blueberries). The available evidence suggests that the heathlands and sandy barrens in the Annapolis valley differ from those further west in Canada and from anthropogenic and coastal heathlands of Nova Scotia in their species composition including particularly the presence of Corema conradii, Hudsonia ericoides and Amelanchier lucida. The need to protect representative examples is supported. [ABSTRACT FROM AUTHOR]

Methods used in the restoration of lowland heath vary depending on edaphic factors at a site and need for introduction of ericaceous propagules. This study investigates the effect of some methods on growth of an important ericaceous species, Heather ( Calluna vulgaris). It also explores whether success of growth of C. vulgaris in restoration schemes is affected by its degree of colonization by ericoid mycorrhizal fungi (ERM). The success of Heather growth was compared at three sites, a control area of natural heathland and two restoration sites. These were a quarry where soil had been translocated but not chemically manipulated and a site on agricultural land where the top soil had been improved but then either stripped away or acidified prior to attempting heathland restoration. Propagules of C. vulgaris were applied either as turves or as clippings. Results show that clippings produced as dense a cover of C. vulgaris as turves over a period of 13 years and that plants in such swards can exhibit a degree of ERM colonization comparable to that found in mature plants growing in natural heathland. Young (<2 years of age) plants of C. vulgaris had less extensive mycorrhizal colonization of their roots, particularly when growing on restored agricultural soils. A relationship was found between lower levels of mycorrhizal colonization and smaller aboveground plant growth. Success of heathland restoration may be improved by finding means to enhance the rate and extent of mycorrhizal colonization of young C. vulgaris growing in a restoration environment. [ABSTRACT FROM AUTHOR]

The decline in grasslands and other species-rich early successional habitats on the coastal sandplains of the northeastern United States has spurred management to increase the area of these declining plant communities. We mechanically removed overstory oak and applied seed from a nearby sandplain grassland on the island of Martha’s Vineyard, Massachusetts, to evaluate this technique for creating an open oak community able to support sandplain herbaceous species. We compared vegetation structure and composition before and after clearing in an area of total tree removal (clearcutting), an area where 85% of tree basal area was removed (savanna cutting), and in adjacent coastal oak forest. Plant responses to clearcutting and savanna cutting were similar. Sandplain herbs colonized at high frequencies after seeding and increased herbaceous cover from less than 7% before clearing to 22–38% three growing seasons later. Pennsylvania sedge ( Carex pensylvanica) increased in cover approximately 6-fold, accounting for 84–90% of the increased herbaceous cover. Other native ruderals and exotic herbs reached 2 and less than or equal to 1%, cover, respectively, after three years. Species richness across cleared treatments increased from 30 to 79 species. All forest species were retained. Forest shrubs and trees initially declined from their dominant cover but rebounded after three years. Tree clearing plus seeding appeared to be a viable management practice for increasing cover of herbaceous sandplain species while causing minimal increases in exotic herbaceous cover. The long-term persistence of sandplain herbs may require periodic disturbances that limit woody regrowth. [ABSTRACT FROM AUTHOR]

Much of the ecology of rare bumblebee species remains poorly understood and in need of further study. It has recently been suggested that differences in the range and rate of decline among bumblebee species may relate to differences in their degree of habitat specialization. We examine biotope use by 17 bumblebee species in the Hebrides, southern UK and South Island, New Zealand. We identify a cluster of widespread and abundant species that occur in almost all biotopes and exploit man-made environments such as gardens and arable margins, this group corresponding to the “mainland ubiquitous” species of previous studies. A second grouping of species includes those associated to varying degrees with heathland. It is notable that some species occupy markedly different biotopes in different parts of their range; for example B. soroeensis is found largely on upland heaths in the Hebrides, but on calcareous grassland in the south. Some species, such as B. subterraneus and B. distinguendus, now survive only in specific rare biotopes and could be mistaken for habitat specialists, but it is clear from their historic distributions that they formerly occupied a broader range of biotopes. Surviving populations of several of the species that have declined most ( B. distinguendus, B. sylvarum, B. muscorum sladeni, B. humilis) exhibit a markedly coastal distribution, when once they were widespread inland. We suggest that this is probably simply because some coastal biotopes are less amenable to agricultural improvement, and so more have escaped the detrimental effects of intensive farming. Our results concur with previous suggestions that bumblebees are generally not habitat specialists, so that the conservation of most bumblebee species could be achieved by restoration of flower-rich unimproved meadows. [ABSTRACT FROM AUTHOR]

Abstract: In two natural heathland vegetations, we analysed the effect of turf cutting on spore numbers of arbuscular mycorrhizal fungi (AMF). Next to this, we performed a controlled factorial experiment to examine the role of AMF for germination and establishment of Arnica montana in both turf cut and non-turf cut situations. AMF spore numbers decreased with soil depth, and, along with the topsoil, almost all AMF spores were removed with the removal of the acidified and/or eutrophied organic layer. Recolonisation of AMF spore numbers after turf cutting was slow: spore numbers of approximately 60–95 sporesg−1 dry soil were found two and a half years after turf cutting, corresponding with 55–70% of AMF spore numbers found in natural field populations of A. montana. Since AMF colonisation increased establishment and biomass, and decreased mortality of A. montana, it was suggested that lack of AMF after turf removal might complicate the establishment of this herbaceous species. Removal of organic material as a management measure should therefore carefully be applied, taking in consideration the low recolonisation rates of AMF as this can markedly effect the success of restoration. [Copyright &y& Elsevier]

The study aimed to determine how quickly heather responds in Scottish moorland once deer grazing pressure is reduced. We monitored heather attributes and deer distribution over ten years in Glen Lui and Glen Derry, two contrasting nearby areas of c. 200 ha at Mar Lodge in the eastern Cairngorms. In one area the deer received winter food, affecting the zonation of their impact. In both areas the deer were initially lightly culled, then culling was increased. Mean heather shoot utilisation was 35% and 48% less in the last five years of the study than initially in the two areas, and was very closely correlated with deer pellet-group counts. In Glen Lui heather cover increased significantly but height increases were small. In Glen Derry heather increased significantly in height but little in cover. We attributed the different response to the presence of a secondary grazer (rabbits, Orycrolagus cuniculus) in Glen Lui and also better conditions for heather growth on the drier soils there; rabbits graze more delicately than deer, taking mainly the shoot tips of heather and thus encourage lateral shoot growth. In Glen Lui heather response also varied between four radial zones based on distance from the feeding grounds. At best, there was appreciable recovery four years after the easing of deer grazing pressure, but average amounts of recovery were modest. [ABSTRACT FROM AUTHOR]

The carnivorous plant Drosophyllum lusitanicum inhabits heathland and ruderal sites in Portugal, Spain and Morocco. In the literature, various theories have been discussed concerning the ability of Drosophyllum to survive the annual dry period in summer. In August 2004, we examined: (1) the microclimate, (2) soil parameters and (3) the physiological conditions of the plants on two sites in Portugal and Spain. First, during the day, plants are exposed to very high air and soil temperatures and very low air humidity. The climatic extremes are not significantly softened by the population, only the wind speed is drastically decreased. During the night, on the other hand, very high air humidity and dew formation could be observed. The harsh climate is accompanied by stressful soil conditions. Second, the soil is completely dry, poor in fine earth, calcium and nutrients and more or less acid. Third, in spite of these climatic and edaphic extremes, all plants were green, produced trapping mucilage and caught numerous animals. Far from being affected by these conditions, Drosophyllum showed even better growth and reproduction on more extreme sites. We analysed the root system and found living fine roots missing. The osmotic value of the plants is rather low and water storage organs are absent. Therefore we conclude that in summer Drosophyllum is nourished by the dew at night. [ABSTRACT FROM AUTHOR]

Question: Can combined sod cutting and liming successfully restore species composition of degraded wet heaths? Location: The Netherlands. Methods: The effects of sod cutting with or without liming on plant species composition were studied in two degraded wet heath areas. Seeds and seedlings of Arnica montana were put out in the treated plots to test the suitability of the restored soil conditions. In addition, seed banks of both degraded areas were studied. Results: Germination, growth and survival of Arnica montana were significantly greater after sod cutting and liming compared to sod cutting alone. At the end of the four-year study period, the number of endangered wet heath species was significantly greater in the sod-cut plots than in the untreated vegetation. Acid-tolerant species were especially positively affected. Additional liming only slightly increased the total number of species over the two-year study period and the number of endangered species did not increase. Viable seeds of most of the endangered species were absent in the seed banks of both areas. Conclusions: Sod cutting is sufficient for the return of acid-tolerant, endangered wet heath species of early successional stages, because their seeds are still present in the seed bank. In contrast, acid-sensitive species likely depend on combined sod cutting and liming, as they need the weakly buffered soil conditions created by these restoration measures. However, successful restoration of formerly species-rich wet heaths is limited significantly by the absence of seeds of the target species in the seed banks. Therefore, re-introduction of wet heath target species in areas with limited seed availability should be seriously considered. [ABSTRACT FROM AUTHOR]

Question: Can prescribed winter burning compensate atmospheric nutrient loads for dry heathlands? What effects does prescribed burning have on nutrient balances, particularly as regards the limiting nutrients N and P? Location: Lueneburg Heath, NW Germany. Methods: In two burning experiments (in 10/15 year old Calluna-stands) nutrient balances (for N, Ca, K, Mg, P) were calculated by analysing nutrient inputs (atmospheric deposition, ash deposition), nutrient stores (above-ground biomass, organic horizon) and nutrient outputs (biomass combustion, leaching). Results: Atmospheric nutrient deposition amounted to 22.8 kg·ha-1·a-1 for N and < 0.5 kg·ha-1·a-1 for P. Nutrient stores in the above-ground biomass were 95/197 kg·ha-1 for N and 5/13 kg·ha-1 for P (first/second experiment, respectively). From these stores 90/53% (for N) and 25/14% (for P) were removed by burning. Effects of leaching on nutrient balances were low. In the first two years after burning, leaching rates of N increased by about 4/6 kg·ha-1, whereas leaching rates of P did not change significantly. Input/output-ratios showed that prescribed burning leads to positive nutrient balances for N, Ca and Mg in the long term. For example, the amounts of N removed by prescribed burning are equivalent to ca. five years of atmospheric inputs. Applied in ten-year cycles, this measure alone cannot prevent N accumulation in the long term. Conclusion: Regarding 10/15 year old Calluna-heaths, we assume that prescribed burning cannot compensate for atmospheric N inputs, thus making long-term changes in the nutritional state inevitable. Therefore, prescribed burning should be applied in combination with high-intensity management measures. [ABSTRACT FROM AUTHOR]

1. Numerous studies describe thresholds at which transitions between alternate ecosystem states occur but few quantitatively delimit these conditions and present them in simple frameworks that are of use in ecosystem management. Previous research on heathland ecosystems has provided a site-specific statistical model that describes the determinants of the threshold point in heath–scrub vegetation transition, but the wider applicability, and thus utility, of this model was unknown. 2. Multi-site experimental manipulations were conducted to assess whether a consistent set of factors limited the recruitment of Betula species into heathland vegetation. Data were pooled and used to fit a single general statistical model. The applicability of this model to a wider range of environments was tested using two independent data sets. 3. The identity of the factors controlling Betula colonization, which include Betula seed bank density, phosphorus (P) availability and disturbance effects, were broadly similar between sites, but the strength of their effect varied widely. 4. The general model (explained deviance 59·8%) described Betula seedling densities as a function of biomass and necromass density, vegetation height, Betula seed bank density, P availability and soil water content. These relationships were complex, with numerous interaction and polynomial terms. 5. Although the model was derived from data from a single community type it was reasonably accurate in the prediction of seedling densities over a wider range of heath conditions. However, data capable of validating predictions of high seedling densities were not available. 6. Synthesis and applications. The apparent success of the general statistical model suggests that an approach incorporating multi-site experiments and statistical modelling can facilitate our understanding of ecosystem state transitions and inform the management of invasive species. By describing Betula invasion as a function of variables that are simple, general descriptions of the environment, the model can potentially inform management in a wide range of conditions. The results suggest that heaths close to seed sources and in the degenerate state of the dwarf shrub cycle are the most vulnerable to invasion, and management should target such sites as a priority. At regional scales, these conditions are probably most common in high soil phosphorus sorption capacity areas, where management should be prioritized. [ABSTRACT FROM AUTHOR]

Abstract: During the last decades, the perennial tussock grass Molinia caerulea has shown an increased abundance in European heathlands, most likely as a result of increased nitrogen deposition and altered management schemes. Because of its deciduous nature, Molinia produces large amounts of litter each year, which may affect the intensity and frequency of accidental fires in heathlands. These fires may influence plant population dynamics and heathland community organization through their effects on plant vital attributes and competitive interactions. In this study, fire-induced changes in competitive ability and invasiveness of Molinia through changes in biomass production, seed set and seed germination under both natural and laboratory conditions were investigated. We found that fire significantly increased aboveground biomass, seed set and germination of Molinia. Seed set was twice as high in burned compared to unburned heathland. Two years after fire, seedling densities in natural conditions were on average six times higher in burned than in unburned heathland, which resulted in increased abundance of Molinia after burning. The seed germination experiment indicated that seeds harvested from plants in burned heathland showed higher germination rates than those from unburned heathland. Hence, our results clearly demonstrate increased invasive spread of Molinia after large and intense fires. Active management guidelines are required to prevent further encroachment of Molinia and to lower the probability of large fires altering the heathland community in the future. [Copyright &y& Elsevier]

Abstract: Climate change constitutes a serious threat for European heathlands as unlike other sources of damage, such as over-grazing, local remediation is not a possibility. Within the large pan-European projects, CLIMOOR and VULCAN, the effect of periodic drought and increased temperature were investigated in four heathland ecosystems along a geographical and climatic gradient across Europe. Fluorogenically labelled substrates for four enzymes (glucosidase, sulphatase, phosphatase, leucine amino peptidase) were used to measure extra-cellular enzyme activity in soil samples from each of the CLIMOOR sites. Microbial extra-cellular enzyme production is linked to microbial activity as well as soil physico-chemical properties, making soil enzymes one of the more reactive components of terrestrial ecosystems and potentially excellent indicators of soil microbial functional status and diversity. Across all sites and over all the substrates, organic matter content was exponentially, inversely related to enzyme activity. Although the increase in temperature produced by the CLIMOOR roofs was small (on average 0.9°C), this was sufficient to increase enzyme activity in all sites (on average by 45%). The increase was within the range of seasonal variability at each of the sites. The effect of drought on enzyme activity was more pronounced in the Northern European sites than the southern European, and most moisture limited, site. This suggests that the effect of temperature increases may be observed across all regions; however, the soils of northern Europe may be more sensitive to changes in rainfall patterns than more moisture limited Southern European soils. [Copyright &y& Elsevier]

Abstract: A parameterization for the dry deposition of SO2 is evaluated by means of four statistical sensitivity studies using a sampling-based approach to sensitivity analysis. Measurements over a heathland, grassland and coniferous forest are used to identify those meteorological and vegetation-specific factors which drive the deposition component of the model (model-based studies) and which are most important in the determination of model-measurement discrepancies. Sensitivity indices and scatter plots for monthly average fluxes indicate that the dominant factors are for most months related to non-stomatal components of the deposition flux. [Copyright &y& Elsevier]

The influence of management and nutrient availability on the vegetation dynamics of heathlands characterised by Calluna vulgaris and Erica tetralix were studied in three mountain sites in Northern Spain. A total of 90 plots (1 m2 each) received different combinations of cutting and twice the estimated background atmospheric deposition of nitrogen (56 kg ha−1 yr−1). One of the two dominant ericaceous species was selectively cut by hand at ground level and their regeneration compared in the presence or absence of the other. The results after 2 years showed significant effects of the fertiliser on the vegetation cover, mainly by favouring perennial herbaceous species. There were less noteworthy effects on the number of flowers and on the annual growth of the ericaceous species. It is concluded that, in the short term, increased nutrients alone, at twice the estimated current atmospheric deposition for the area, will not alter significantly the composition of the mountain heathlands. However, once the stands reach the mature phase, the capacity of the community to regenerate after a severe disturbance diminishes. A drastic impact, such as cutting may not result in re-growth of the same shrub species but in replacement by herbaceous species, which will also benefit from the increased nutrients. [ABSTRACT FROM AUTHOR]

To study the impact of high atmospheric nitrogen deposition on the leaching of NOand NHbeneath forest and heathland vegetation, investigations were carried out in adjacent forest and heathland ecosystems in Northwest Germany. The study area is subjected to high deposition of nitrogen ranging from 15.9 kg ha-1 yr-1 in bulk precipitation to 65.3 kg ha-1 yr-1 beneath a stand ofPinus sylvestrisL. with NH4-N accounting for 70-80% of the nitrogen deposited. Considerable leaching of nitrogen compounds from the upper horizons of the soil, mostly as nitrate, occurred at most of the forest sites and below a mixed stand ofCalluna vulgaris(L.) Hull. andErica tetralix, but was low in aBetula pubescensEhrh. swamp forest as well as beneathErica tetralixL. wet heath and heath dominated byMolinia caerulea(L.) Moench. Ground water concentrations of both NO3-N and NH4-N did not exceed 1 mg L-1 at most of the sites investigated. [ABSTRACT FROM AUTHOR]

Current restoration measures of degraded, acidified heathland ecosystems have not always been successful in the Netherlands. Positive effects of a restored hydrology are often counteracted by acidification of the soil and the local groundwater system. Liming of the heathlands in the catchment of moorland pools might contribute to the restoration of both habitats. Experimental catchment liming was carried out in two degraded Dutch heathlands, with doses varying between 2 and 6 tons/ha. Catchment liming resulted in increased pH and base cation concentrations in the highest elevated limed parts, as well as in the lower situated, nonlimed heath areas and moorland pools. Generally, catchment liming created suitable conditions for the return of heathland target species, and the positive effects lasted for at least 6 years. The response of the heathland vegetation to the liming has, however, been slow because only a small number of endangered plant species increased in abundance. In contrast, four Red List soft-water macrophytes strongly increased in abundance in the moorland pool. Our results show that, even with the slow return of Red List plant species, catchment liming can be a successful management tool for the restoration of the acidified heathland landscape. [ABSTRACT FROM AUTHOR]

The effects of the fire retardant Phos-Chek D75R on species composition, survival and growth of eastern Australian heathland vegetation are described. Two sites in Victoria were selected, Victoria Valley in the Grampian Ranges and Marlo in East Gippsland. Both areas supported heathland vegetation that was long, unburnt and relatively undisturbed. Plots were subjected to single applications of increasing concentrations of retardant (0.5, 1.0 and 1.5 L fire retardant m-2) or no additional fire retardant (?Control' and ?Water only' treatments). A single application of Phos-Chek did not appear to significantly change species composition or projected foliage cover of the major life forms of native heathland vegetation. However, it did cause whole plant and shoot death of key species Allocasuarina paludosa, Banksia marginata, Leptospermum continentale and L. myrsinoides, and was observed to affect other species. The fertilising effect of the fire retardant generally increased shoot growth of the key species but did not significantly increase the overall height of these species. The application of fire retardant enhanced weed invasion, particularly when supplied at higher concentrations. A number of research recommendations are made from this preliminary investigation. [ABSTRACT FROM AUTHOR]

• The effects of increasing ammonium concentrations in combination with different pH levels were studied on five heathland plant species to determine whether their occurrence and decline could be attributed to ammonium toxicity and/or pH levels.• Plants were grown in growth media amended with four different ammonium concentrations (10, 100, 500 and 1000 µmol l−1) and two pH levels resembling acidified (pH 3.5 or 4) and weakly buffered (pH 5 or 5.5) situations.• Survival ofAntennaria dioicaandSuccisa pratensiswas reduced by low pH in combination with high ammonium concentrations. Biomass decreased with increased ammonium concentrations and decreasing pH levels. Internal pH of the plants decreased with increasing ammonium concentrations. Survival ofCalluna vulgaris,Deschampsia flexuosaandGentiana pneumonanthewas not affected by ammonium. Moreover, biomass increased with increasing ammonium concentrations. Biomass production ofG. pneumonanthereduced at low pH levels.• A decline of acid-sensitive species in heathlands was attributed to ammonium toxicity effects in combination with a low pH.New Phytologist(2005)doi: 10.1111/j.1469-8137.2005.01338.x© New Phytologist(2005) [ABSTRACT FROM AUTHOR]

In the Mediterranean region, cycles of controlled burning combined with continuous grazing appear to have been an effective tool for maintaining isolated Calluna vulgaris heathlands in the form in which they occur in many places in the Atlantic region. Changes in land use and management of the mosaic of extensively exploited heathland and associated grassland over recent decades, such as bringing land into cultivation followed by its abandonment and the prohibition of fires has resulted in a process of transformation into new shrub communities with lower biodiversity. In the Mediterranean region, these changes are similar to those described in the Atlantic area, but encroachment occurs faster and could lead ultimately to afforestation by Mediterranean woodland.In a study area of 300 ha of heathland in the Spanish Mediterranean basin (specifically, in the Montseny Natural Park and Biosphere Reserve), comparison of present and former vegetation showed that shrub cover increased from 15% in 1967 to 32% in 2000. Broom (Cytisus scoparius) was the main invasive species in abandoned crop fields, whereas Mediterranean holm oak forest (Quercus ilex) increased by 18%. The surface area of fernlands doubled and C. vulgaris heathlands decreased from 35% to just 9% during the same period. Intermixed grasslands also decreased moderately and progressively from 4% to 3%.It seems probable that cycles of fires are more important in terms of shrub control and biodiversity conservation than continuous grazing alone, even at a high rate of stocking (four small ruminants per hectare per year). This encroachment process throws into relief the role that isolated habitats can play as a monitor of land use changes. [Copyright &y& Elsevier]

Question: The significance of disturbances caused by periodical inundation was investigated with respect to its effects on vegetation dynamics, species richness and fluctuations, and to the relevance of certain plant properties. Location and Method: At a sod-cut stand within nutrient-poor inland sand dunes, permanent plots along a transect were surveyed over a period of up to nine years after sod cutting. Results: In contrast to never inundated plots, periodically inundated plots were characterized by low vegetation cover and by high numbers of species belonging to many different communities. each of them with a low cover. Periodical inundations favoured the presence of pioneers, species tolerant of disturbances. species adapted to wet conditions and stoloniferous species. Furthermore. annual fluctuations of species within each plot were higher and most species occurred only sporadically. Discussion: A comprehensive model is presented describing the relevant processes identified in the littoral zone. Changing water tables result in the creation of gaps. The re-colonization of these gaps follows mainly from vegetative regeneration and less to the dispersion of diaspores. highest species numbers in the zone of moderate disturbances result from a high rate of re-colonization in spite of local extinctions following each disturbance event. It is suggested that colonization abilities are among the most important features for species occurrence at a site rich in disturbances (more important than competitive abilities and more important than a slow rate of displacement). For nature conservation such sites are very important, because they allow (rare) pioneer species to survive for longer periods of time. [ABSTRACT FROM AUTHOR]

1. Semi-natural habitats have been shaped by human disturbance regimes for centuries. Spatially and temporally heterogeneous land-use practices, such as cutting, burning, grazing and turf-cutting, have resulted in complex mosaic landscapes that are of high priority for conservation in Europe. Contemporary conservation subjects these systems to management regimes that are generally less diverse, in terms of disturbances and fine-scale temporal and spatial variability, than traditional land use, but the ecological consequences of these simplifications are unclear.2. We investigated the interactive effects of fire and grazing on plant species composition and diversity along local environmental (moisture) gradients in coastal heathlands. A replicated series of post-fire successions (n = 12) was initiated in three heathland habitats and the areas subjected to two grazing regimes. Floristic and environmental data were recorded in permanent plots over a 5-year period. Community data were analysed using multivariate ordination techniques (principal components analysis, partial redundancy analyses, and principal response curves) and generalized linear models.3. Fire induced strong successional trends in the species composition of the heathlands. These trends differed among heathland habitats, and with grazing. Strong interactions between fire, habitat and grazing implied that the effect of grazing on the successional dynamics differed among habitats. Species diversity decreased in the first year after fire but increased beyond the pre-fire levels during succession. This trend was not affected by local environment or grazing, although there were main effect differences in diversity between environments and grazing regimes.4. Synthesis and applications. Our results demonstrate that the two management practices do not have simple additive effects within the semi-natural system studied, as grazing created ecological opportunities for additional sets of species, increased variability among habitats, and added complexity to the post-fire successional dynamics. In order to preserve diversity, conservation management should thus aim to preserve the level of complexity of the traditional management regimes, both in terms of the actual disturbances (e.g. fire and grazing) as well as the spatial scales at which they are applied. Further, the considerable change in these effects along the local environmental gradient brings into question the efficiency of general management prescriptions, and indicates that local environmental variability should be taken into account in the conservation of semi-natural habitats.Journal of Applied Ecology(2005)42, 139–149doi: 10.1111/j.1365-2664.2005.00982.x [ABSTRACT FROM AUTHOR]

The advent of remote-sensed satellite land cover data has provided the opportunity to assess the relationship between invertebrate species distributions and individual land cover types. Water beetle species occur in habitats within specific land cover types and the relationship between the distribution of water beetle species and land covers at the regional scale was investigated using records of 154 species from 1018 sites in north-east England. The land covers of tilled land and urban in the lowlands and of shrub heath and heath grassland in the upland areas proved to be most important in explaining the distribution of species. There were both positive and negative associations between some species and other covers such as woodland and the coast. However, a considerable number of species, generally those with a large number of records, showed no strong relationships with any land cover types. The integration of water beetle species recording data and remote-sensed land cover data as a basis for predicting and monitoring both species distribution and environmental change is discussed. [ABSTRACT FROM AUTHOR]

The wind-pollinated, dioecious shrubJuniperus communisL. is declining in Dutch heathlands, mainly because recruitment is scarce. Aside from ecological factors, inbreeding associated with reduced population size and isolation in the currently fragmented landscape might explain this decline. However, the breeding system of this species largely prevents inbreeding. We assessed variation in 18 allozyme loci in 12 Dutch juniper populations to investigate population structure and to test the hypothesis that small populations have less genetic variation and show more inbreeding than large populations. Variation was high for a species with a fragmented distribution, but similar to values observed in other juniper species. The proportion of polymorphic loci (P) ranged between 0.72 and 0.83, expected heterozygosity (H e) ranged between 0.16 and 0.27 and the mean effective number of alleles per locus (A) ranged between 2.5 and 3.3. Population size was not correlated with genetic variation or with sex ratio. Deviations from Hardy–Weinberg expectations, mainly heterozygote deficiencies, were mostly observed in larger populations, which appear to have been broken up into smaller subunits. Differentiation among populations was small (F ST = 0.026) and there was a significant departure from random mating (F IS = 0.174). Geographic and genetic structures were not related. Our data suggest that gene flow in this wind-pollinated shrub was high during the establishment phase of the current populations. Gene exchange by pollen and seeds may be less extensive in the present-day landscape. However, juniper decline is not likely to be caused by genetic factors. Alternative hypotheses include changed heathland disturbance regimes, pollen limitation, seed predation and age-related fecundity reductions. Implications for the restoration of juniper populations are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Soils of wet heathlands have lost their buffering capacity as a result of acidification, eutrophication, and desiccation. Many characteristic plant species have disappeared from these ecosystems because of the unfavourable soil conditions. Restoration projects should aim at counteracting the negative effects of acidification in particular. Blocking of drainage ditches to increase groundwater influence and lime application to improve soil pH and buffering capacity have been applied in many restoration projects in the Netherlands, but with varying success. In this mesocosm experiment, the restoration of the soil buffering capacity of degraded wet heath soil was studied. Groundwater with low or high calcium and bicarbonate concentrations and low or high flow velocities was applied to soil columns filled with wet heath soil. Measurements of the nutrient concentrations in soil pore water and soil extractions revealed that restoration of the soil buffering capacity was optimal at both high calcium concentrations and high through-flow velocity. It was concluded that high concentrations of calcium are more effective than high flow velocity in the reloading of the buffer capacity. Furthermore, the restoration was limited to the soil layers that were in direct contact with the groundwater, which stresses the need for higher groundwater levels in degraded wet heathlands. [Copyright &y& Elsevier]

The results from three long-term field manipulation studies of the impacts of increased nitrogen deposition (0-120 kg N ha-1 yr-1) on lowland and upland heathlands in the UK were compared, to test if common responses are observed. Consistent increases inCallunafoliar N content and decreases in litter C:N ratios were found across all sites, while increases in N leaching were not observed at any site over the range 0-80 kg ha-1 yr-1. However, the response ofCallunabiomass did vary between sites, possibly reflecting site differences in nutrient status and management histories. Five versions of a simulation model of heathland responses to N were developed, each reflecting different assumptions about the fate and turnover of soil N. Model outputs supported the deduction from mass balance calculations at two of the field sites that N additions have resulted in an increase in immobilisation; the latter was needed to prevent the model overestimating measured N leaching. However, this version of the model significantly underestimatedCallunabiomass. Model versions, which included uptake of organic N byCallunaand re-mobilisation of N from the soil organic store provided some improvement in the fit between modelled and field biomass data, but re-mobilisation also led to an overestimation of N leaching. Quantification of these processes and their response to increased N deposition are therefore critical to interpreting experimental data and predicting the long-term impacts of atmospheric deposition on heathlands and moorlands. [ABSTRACT FROM AUTHOR]

Aim To study the effects of the degree of fragmentation of heathland patches on their species richness and species composition, and to infer the ecological mechanisms behind the observed patterns. Location The heathland patches of the north-western part of Flanders, Belgium. During the last 200 years, the heathland area in this study area has been reduced from c. 10,000 to c. 40 ha, yielding c. 150 small and highly isolated relic fragments. Methods Different isolation measures were calculated for each of the 153 inventoried heathland patches. The influence of isolation, area and habitat diversity on species richness was investigated using correlation techniques. Community composition of the patches was tested for nestedness, and the mechanisms potentially underlying this pattern were determined. Results and main conclusions Both the analyses at the species richness and community composition level yielded evidence for a positive species-area relation. This relation was not caused by higher habitat heterogeneity in larger patches. Patch isolation, measured in different ways, however seemed much more important in explaining species richness and community composition than fragment area. Our results indicate that area effects are overcompensated by the rescue-effect: if a patch is close to other patches, species can disperse between them and prevent the species from going extinct. Species having a short living seed bank were also more sensitive to isolation than species with a long living seed bank, indicating that the latter most probably depend on the seed bank to survive periods when environmental conditions are harsh. Analogously to the spatial rescue-effect, the existence of a persistent seed bank may lead to a sort of temporal rescue-effect, where the extinction of a plant species is prevented through survival in the seed bank of a patch. [ABSTRACT FROM AUTHOR]

Soil water chemistry and element budgets were studied at three northwestern EuropeanCalluna vulgarisheathland sites in Denmark (DK), The Netherlands (NL), and Wales (UK). Responses to experimental nighttime warming and early summer drought were followed during a two-year period. Soil solution chemistry measured below the organic soil layer and below the rooting zone and water fluxes estimated with hydrological models were combined to calculate element budgets. Remarkably high N leaching was observed at the NL heath with 18 and 6.4 kg N ha-1 year-1 of NO3-N and NH4-N leached from the control plots, respectively, indicating that this site is nitrogen saturated. Increased soil temperature of +0.5°C in the heated plots almost doubled the concentrations and losses of NO3-N and DON at this site. Temperature also increased mobilization of N in the O horizon at the UK and DK heaths in the first year, but, because of high retention of N in the vegetation or mineral soil, there were no significant effects of warming on seepage water NO3-N and NH4-N. Retention of P was high at all three sites. In several cases, drought increased concentrations of elements momentarily, but element fluxes decreased because of a lower flux of water. Seepage water DOC and DON was highly significantly correlated at the UK site where losses of N were low, whereas losses of C and N were uncoupled at the NL site where atmospheric N input was greatest. Based on N budgets, calculations of the net change in the C sink or source strength in response to warming suggest no change or an increase in the C sink strength during these early years. [ABSTRACT FROM AUTHOR]

The effects of sod cutting, a common restoration measure to remove excess nutrients from grass-dominated heathlands, on nitrification were studied in dry and wet Dutch heathlands and in incubation experiments. In the field, soil ammonium and nitrate concentrations were measured after treatment by sod cutting, with or without additional liming. Potential net nitrification was measured by incubating soil samples of all treatments with extra ammonium in a climate chamber at pH 6. Potential net nitrification of heaths dominated byMolinia caeruleawas significantly higher than that of dwarf-shrub dominated heaths. Sod cutting of the former areas significantly decreased potential net nitrification, whereas in the latter areas no differences were found. Liming of sod-cut soils greatly increased potential net nitrification and the accumulation of ammonium in the soil up to toxic concentrations could be prevented. Our results show that the combination of sod cutting and liming would create suitable soil conditions for the germination and establishment of endangered plant species of dry and wet heathlands. The success of restoration projects of these areas can thus be increased. [ABSTRACT FROM AUTHOR]

Abstract. Over the past decades outdoor recreation has become progressively more important and as a result human‐induced potential damage has increased. In this study, short‐term effects – a 2‐yr period – of human trampling on some common forest and heath communities in Central Belgium were studied experimentally. Vulnerability to disturbance was compared among plant communities in terms of resistance, resilience and tolerance, which are based on cover measurements. The herb layer of the examined mesophilous forest communities appeared to be more sensitive than the heath and dry forest community, which were dominated by more resistant graminoid (Molinia caerulea, Deschampsiaflexuosa) and dwarf‐shrub species (Vaccinium myrtillus, Calluna vulgaris, Erica tetralix). The analysis showed that site structure and vegetation were already affected by low intensities of trampling, while vegetation recovery during the first year after trampling was limited in most plant communities. Recovery during the second year in vegetation cover as well as height was most pronounced in mesophilous forest communities. Occasional trampling clearly can lead to increased visual evidence of previous use and continued recreational disturbance. Therefore management plans should discourage hiking activity off paths and restrict recreation activities to the least vulnerable communities. [ABSTRACT FROM AUTHOR]

The UK Biodiversity Action Plan has identified the creation of lowland heathland as an important objective. Heathland restoration studies have identified soil pH, elevated soil nutrients and large weed seed banks as major problems in the restoration of heathland vegetation on ex-arable land. Heathland vegetation is usually found on nutrient-poor acidic soils. Creating acidic soil conditions on ex-arable sites thus may produce a suitable environment for the establishment of heath vegetation. Soil acidification by the addition of sulphur has been shown to reduce the soil pH and the availability of nutrients in arable soils. A series of experiments was established to investigate the effects of soil acidification using sulphur on the establishment of Calluna vulgaris and the development of weed vegetation. The application of sulphur at 0.24 kg m-2 to an arable soil was found to increase the survival rate of C. vulgaris cuttings planted in it. The mechanism of increased C. vulgaris survival appeared to be by sulphur application significantly reducing the cover of arable weeds arising from the soil seed bank. Higher rates of sulphur application (0.36 and 0.48 kg m-2) resulted in the death of many C. vulgaris plants. However C. vulgaris seedlings were able to establish successfully on these ex-arable soils within 18–24 months following the addition of these levels of sulphur. The application of sulphur appears to offer a practical solution to heathland creation on ex-arable land. However, it may be necessary to provide an interval of between 18 and 24 months between the application of sulphur and the addition of C. vulgaris plants or seeds for the successful establishment of heathland vegetation. [Copyright &y& Elsevier]

Gradients in stressed areas potentially provide a powerful tool to interpret relations between soil biodiversity and site quality. We measured soil chemistry, soil microbiology and nematodes along three transects representing a fertility gradient and at a disturbed site near a road in a Dracophyllum subulatum-dominated shrubland in which frosts are a major factor in preventing succession to forest; we used D. subulatum size as a site-quality index. Significant correlations between both shrub height and shrub growth rate and volumetric measures of total soil phosphorus and anaerobically mineralisable nitrogen indicate that nitrogen and phosphorus regulate plant growth. Microbial biomass and total nematode abundance significantly increased with greater plant growth, presumably in response to greater litter input. Conversely, neither heterotrophic microbial diversity nor nematode diversity was correlated with shrub performance along the transects. Litter was from a single species and thus likely similar in quality so changes in microbial or nematode diversity might not be expected. In this oligotrophic environment, nutrient levels were not only the important regulators of plant growth but also appeared to have an indirect influence on the size of the microbial and nematode populations. [Copyright &y& Elsevier]

Many areas of heathland in Europe have seen a decline in the area and condition of Calluna vulgaris (heather)-dominated vegetation, with subsequent declines in the associated faunal interest. Grazing, alongside burning, is still the predominant means of managing heathland vegetation, and, therefore, it is by manipulating this management that cost-effective improvements in vegetation condition can be made. This paper investigates the suitability of different grazing treatments for rehabilitating degraded ‘dry heath’. Treatments varied in the intensity (0–1.9 sheep ha−1 year−1) and timing (summer vs. winter) of sheep grazing. These treatments were compared with the behaviour of vegetation outside the fenced area kept under the previous management (open access all year round). As rabbits were common on the site, fences were erected to prevent access to the sheep grazed plots. Vegetation composition remained stable outside the fenced area, whilst all the fenced treatments showed a decrease in heather utilisation and an increase in the relative frequency of heather over the 5 years of the experiment. The increase was in proportion to the reduction in stocking rate, with only slow increases in relative frequency observed in the high grazing treatments (winter and summer). Other species that benefited from reducing grazing included Empetrum nigrum and Vaccinium myrtillus, whilst declines were observed for Agrostis capillaris and total monocotyledonous species. Only small overall differences were observed between the winter low, summer low and no sheep grazing treatments. However, a difference in response was present between the sheep exclosures and the sheep+rabbit exclosures, indicating that rabbits were having a noticeable effect on heather recovery at this site. On this degraded ‘dry heath’ system, imposing a reduction in stocking density improved the condition of the dwarf shrubs present and reduced the grass component of the vegetation. There was little effect of the timing of grazing, such that a reduction in sheep numbers to 0.8/0.9 sheep ha−1 year−1, to give utilisation levels of below 20%, can achieve the desired result of improving vegetation condition whilst still achieving some economic return from grazing. However, the wide range of ‘sustainable’ stocking densities for different heathland systems highlights the need to base effective management on measured utilisation rather than on stock numbers. [Copyright &y& Elsevier]

Maintenance and restoration of grasslands, heathlands, and shrublands are high priorities for conservation due to their diversity of uncommon species and assemblages and their ongoing decline resulting from invasion by shrubs and trees. Much of the literature and management concerning openlands emphasizes burning to control woody growth, based on the interpretation that these habitats and their species assemblages were widespread during the pre-European period as a consequence of natural disturbance and Native American land use. By focusing on the coastal region of New England–New York, which harbors excellent examples of these habitats, is characterized by many natural disturbances (e.g. hurricanes, fire, salt spray), and supported relatively dense Native American populations, we assess the paleoecological, archaeological, historical, and modern ecological evidence supporting this perspective.We conclude that: (1) pre-European uplands, including coastal areas, were predominantly forested and that openland habitats were uncommon because natural and human disturbance was infrequent and local; (2) extensive openland vegetation developed only with widespread European forest clearance and land use; (3) assemblages occupying grasslands, shrublands, and heathlands apparently have no lengthy history and are comprised of species that combined opportunistically over recent centuries; (4) the decline of grasslands, heathlands, and shrublands is a century-old phenomena related to a decline in agricultural land use, especially grazing, mowing, plowing and burning; (5) effectively all conservation areas supporting these openland assemblages experienced intensive historical land use; and (6) the modern distribution, composition, and structure of these habitats are largely determined by European land use.Recognition that openland assemblages have cultural origins does not diminish the biological, cultural, or aesthetic value of these habitats. However, it does suggest that grasslands, heathlands and shrublands may be best managed using a combination of approaches that replicate the effects of historical land use. Conservationists should recognize that most of these landscapes have cultural origins and are inherently dynamic; that some vegetation structures and communities cannot be maintained continuously on a given site; and that management is most effective when based on historical and ecological studies leading to clearly defined objectives and rigorous long-term measurement and re-evaluation. [Copyright &y& Elsevier]

The article discusses the performance of place in nature reserves. It focuses on the Agglestone, a rock on Godlingston Heath, part of the Studland peninsula in Dorset, England, and a nearby fence. The author comments nature reserves as local spaces and the relationship between human and nonhuman nature. He also explores the reserve as a scientific object and analyzes the creation of expert knowledge. An ecological survey of the area conducted in the 1930s by Captain Cyril Diver, the first Director-General of the organization the Nature Conservancy, is considered, as is the British government's Biodiversity Action Plan (BAP).

In the Chaîne des Puys, a mid-elevation volcanic mountain of the French Massif Central, Scots pine proves to be an ‘invasive’ species colonizing abandoned lawns or heathlands, and forms in a few years monospecific natural forests. Most of the abandonment occurred 30 to 40 years ago and this process has now stopped. Thus, we lack data on the very first phase of tree colonization. We anticipate that a simulation tool could bring an appreciable help in (i) rebuilding the entire colonization process – including the initial phase – of pine settlement and (ii) answering questions about the origin of the narrow and unimodal distributions of age of pine stands we observed. In addition, such a simulator could help managers to forecast extension of Scots pine and to predict growth and evolution of present secondary forests. A spatially explicit individual-based model is presented. The model takes into account both space and time and includes growth of trees, seed production and seed dispersal, death and competition between individuals. The influence of the initial parameters are analyzed and elements of validation given. The model was then used to predict tree settlement and stand establishment using the initial conditions from a natural stand studied in the field whose characteristics before abandonment were known (number and age-distribution of trees, location of mother trees, time of abandonment). Three simulations were achieved by using the same initial conditions but following different scenarios for the recruitment process. The scenario of a fluctuating resistance of the resident vegetation (that controls the susceptibility of the environment to tree establishment) seemed as one of the most probable to explain the actual stand characteristics. We thus concluded that dynamic models could be improved by taking into account the resistance of the vegetation to colonization as a fluctuating parameter instead of a static and permanent attribute. [ABSTRACT FROM AUTHOR]

Abstract. Based on both theoretical and empirical studies there is evidence that different species abundance distributions underlie different species-area relationships. Here I show that Australian and Californian shrubland communities (at the scale from 1 to 1000 m2 ) exhibit different species-area relationships and different species abundance patterns. The species-area relationship in Australian heathlands best fits an exponential model and species abundance (based on both density and cover) follows a narrow log normal distribution. In contrast, the species-area relationship in Californian shrublands is best fit with the power model and, although species abundance appears to fit a log normal distribution, the distribution is much broader than in Australian heathlands. I hypothesize that the primary driver of these differences is the abundance of small-stature annual species in California and the lack of annuals in Australian heathlands. Species-area is best fit by an exponential model in Australian heathlands because the bulk of the species are common and thus the species-area curves initially rise rapidly between 1 and 100 m2 . Annuals in Californian shrublands generate very broad species abundance distributions with many uncommon or rare species. The power function is a better model in these communities because richness increases slowly from 1 to 100 m2 but more rapidly between 100 and 1000 m2 due to the abundance of rare or uncommon species that are more likely to be encountered at coarser spatial scales. The implications of this study are that both the exponential and power function models are legitimate representations of species-area relationships in different plant communities. Also, structural differences in community organization, arising from different species abundance distributions, may lead to different species-area curves, and this may be tied to patterns of life form distribution. [ABSTRACT FROM AUTHOR]

Increasing dominance of grass species such as Deschampsia flexuosa on lowland dry heathlands is a major problem for land managers. This problem is especially acute in north-west Europe where replacement of dwarf-shrubs by grasses has been linked to high levels of nitrogen deposition. Interactions between Calluna vulgaris and D. flexuosa were examined using pot experiments under a variety of watering (drought vs. no drought), nitrogen addition (10 vs. 50 kg N ha-1 yr-1) and soil type (peaty vs. sandy) regimes. Two experiments using identical replacement series designs were used to investigate interactions between these two species at the seedling and young plant stage. Response of the two species to the environmental variables was different for seedlings and young plants. In the seedling experiment D. flexuosa responded significantly to soil type only, with greater cover on peaty soil than on sandy soil after 6 months. C. vulgaris germination showed a significant response to watering regime, with fewer seedlings in plots that had a drought treatment imposed. When the experiment was repeated using young plants of C. vulgaris and D. flexuosa both species responded significantly to soil type only. Height, % cover and shoot biomass of both species were greater when grown in peaty soil than when grown in sandy soil. Watering and nitrogen addition had few significant effects. Species interactions were mainly one-way. C. vulgaris biomass yield was reduced when grown in mixture with D. flexuosa, whilst D. flexuosa yield was unaffected by the presence of C. vulgaris. The yield density curve for D. flexuosa indicated that intra-specific competition was occurring at planting densities above 29 plants m-2 whilst this was not seen for C. vulgaris. The effect of soil type on species interactions was also investigated. C. vulgaris was best able to compete with D. flexuosa on sandy soils where the shoot biomass ratio was greatest (C. vulgaris:D. flexuosa= 1:4.4). Differences in the responses of these species to the environmental variables investigated may help to explain heathland vegetation changes seen under field conditions. [ABSTRACT FROM AUTHOR]

The article discusses the use of historical and ecological approach to determine the influence in Cape Cod National Seashore, the national seashore found in Massachusetts. Research sources suggested that past agriculture generated ecosystem and much reforested. Using of management approach mimic past agricultural practices to maintain and restore the importance of habitats.

Overstorey shrub species are known to influence the composition of the understorey in Southern Hemisphere heathlands. Overstorey densities are susceptible to variations in fire frequency; thus, fire regimes may influence overstorey/understorey interactions and overall floristic composition. We compared patches of Banksia heath which had supported an overstorey during a fire interval of about 30 y with patches where the overstorey was absent during the same period, and tested for differences in species composition as a function of overstorey presence. Floristic composition varied significantly between overstorey patches and open patches. Most species were less abundant in overstorey patches, however some were more abundant. The relative abundance of species in relation to overstorey was unrelated to their fire response, propagule longevity or propagule storage location. There was significantly less biomass in overstorey patches compared with open patches. The effect of the overstorey varied with soil moisture. In a dry area, the number of species was lower in overstorey patches, with fewer herb and shrub species present compared with open patches. Fewer species were recorded in a wetter area, but overstorey had no effect on the number of species recorded. Reduced intensity of competition among understorey species in overstorey patches could be responsible for the higher abundance of some species in these patches. We postulate that full diversity will be maintained when the density of overstorey shrubs fluctuates widely over a relatively short period of time. This is most likely when fire frequency is highly variable. [ABSTRACT FROM AUTHOR]

Abstract Aim This study evaluates the long-term history of grassland, heathland and shrubland communities that are high priorities for conservation in the north-eastern US and support numerous globally rare species. Such an historical perspective is necessary in order to develop appropriate conservation and management approaches for these communities. Location The study area encompasses the coastal region that extends from Cape Cod, MA to Long Island, NY, including the islands of Nantucket, Martha's Vineyard, and Block Island. Methods In order to determine whether open-land habitats occurred in the study region prior to European arrival in the seventeenth century and to assess changes to these communities through the historical period, a wide range of palaeoecological, archaeological, ethno-historical, biological and field data were reviewed. Information about the history of human impacts on these communities was used to interpret landscape change over time and to evaluate current and potential conservation and management approaches. Results The region was predominantly wooded prior to widespread Euro-American land clearing beginning in the seventeenth century, with some areas of early successional habitats, primarily on exposed sites and near Native American settlements. Grasslands, heathlands and shrublands increased dramatically as a result of intensive and primarily agricultural disturbance through the historical period. The decline in recent decades of these communities results from extensive residential and commercial development, and from widespread abandonment of traditional agricultural practices, especially intensive grazing. Main conclusions Despite considerable uncertainty as to the pre-European distribution and abundance of species characteristic of grasslands, heathlands and shrublands, historical disturbances have been sufficiently widespread and severe that it is unlikely that modern species assemblages closely resemble those that occurred prior... [ABSTRACT FROM AUTHOR]