Disentangling the role of management,vegetation structure,and plant quality for Orthoptera in lowland meadows

Seminatural grasslands provide habitats for various species and are important for biodiversity conservation. The understanding of the diverse responses of species and traits to different grassland managenient methods is therefore urgently needed. We disentangled the role of grassland management (fertilization and irrigation), vegetation structure (biomass, sward height) and plant quality (protein and fiber content) for Orthoptera communities in lowland hay meadows in Germany. We found vegetation structure to be the most important environmental category in explaining community structure of Orthoptera (species richness, total individuals, fiinctional diversity and species composition). Intensively used meadows (fertilized, irrigated, high plant biomass) were characterized by assemblages with few species, low functional diversity, and low conservation value. Thereby, the relatively moderate fertilizer inputs in our study system of up to -75 kg N/ha/year reduced functional diversity of Orthoptera, while this negative effect of fertilization was not detectable when solely considering taxonomic aspects. We found strong support for a prominent role of plant quality in shaping Orthoptera communities and especially the trait composition. Our findings demonstrate the usefulness of considering both taxonomic and functional comp on ents (functio nal diversity) in biodiversity research and we suggest a stronger involvement of plant quality measures in Orthoptera studies.     

The impact of grazing management on Orthoptera abundance varies over the season in Mediterranean steppe-like grassland

As semi-natural grassland has a high level of biological diversity, understanding the effects of grazing and its variation over time is important in order to identify sustainable grazing practices. We measured temporal variation in Orthoptera abundance and spatial vegetation structure during seasonal grazing in an extensive sheep-farming system. We studied five grazed pasture areas (pre-grazing and post-grazing) and two adjacent ungrazed grasslands. We recorded the total abundance of Orthoptera and described the vegetation structure of 175 replicate plots (25 per pasture/grassland) during six field sampling sessions. We demonstrated that the impact of grazing on Orthoptera abundance is species-specific and greatly varies over the grazing season. The decrease of phytovolume is significant after 4–7 weeks of sheep grazing. Total Orthoptera abundance was higher in pre-grazed plots than in ungrazed plots, and higher in ungrazed plots than in post-grazed plots. These differences were particularly high during the peak of adult abundance. No difference in species richness was observed between grazing intensities. Total Orthoptera abundance positively correlated to phytovolume only when grazing pressure was high. However, the relationship between abundance and phytovolume differed between species. Extensive grazing by sheep tends to homogenize spatial vegetation structure and to temporarily reduce total Orthoptera abundance at pasture scale. However, rotational grazing allows spatial and temporal heterogeneity in vegetation structure to be maintained at farm scale, heterogeneity that is beneficial for Orthoptera. In contrast, absence of grazing has a negative impact on Orthoptera abundance as it favours the accumulation of litter, which is detrimental for a high proportion of xerothermophilic Orthoptera associated with bare ground and short vegetation.     

高寒草地植物群落关键种对不同放牧家畜组合放牧的响应

如何通过合理的利用方式提高高寒草地管理水平,实现其可持续利用一直是草地生态学领域的研究热点。为明确不同放牧家畜组合下高寒草地植物群落关键种的演替规律及其驱动因素,基于中等放牧强度设置了不同放牧家畜组合放牧样地（牦牛单牧、藏羊单牧、牦牛藏羊1 ： 2混牧、牦牛藏羊1 ： 4混牧、牦牛藏羊1 ： 6混牧）以及围封样地,并在连续放牧处理7年后系统分析了不同放牧家畜组合下植物群落特征与土壤理化性质变化,以期确定最优放牧组合。结果表明：（1）不同放牧家畜组合均会显著降低高寒草地植物盖度,但对其物种丰富度与多样性指数的影响并不显著。（2）牦牛藏羊1 ： 2混牧下植物群落特征与禁牧处理下植物群落特征较为相似,且牦牛藏羊1 ： 2混牧下的植物群落稳定性最强、组织水平最高。（3）牦牛单牧与1 ： 2混牧下关键种为矮生嵩草;藏羊单牧下关键种为天山针茅;1 ： 4混牧下关键种为星毛委陵菜;1 ： 6混牧与围封下关键种为赖草。（4）围封能够显著降低土壤容重,藏羊单牧则会显著增加土壤容重与土壤速效氮、磷含量。（5）土壤速效氮、容重与含水量是驱动不同放牧家畜组合下植物群落关键种演替的重要理化因子。综上所述,中等放牧强度下,牦牛藏羊1 ： 2混牧是青藏高原高寒草地较为理想的利用方式。此外,相较于单纯增加草地物种丰富度或多样性,建立植物群落物种之间的有效关联是提高青藏高原高寒草地管理水平的另一关键途径。     

Short-term effects on sheep pastureland due to grazing abandonment in a Western Mediterranean island ecosystem: A multidisciplinary approach

Changes of pasture communities consequent to management practices resulting from land abandonment considerably affect the structure and function of the ecosystem. This study analyses the consequences of grazing abandonment in terms of plant and soil microbial diversity and fertility, on a Mediterranean upland sheep pasture, over a short period (five years). Grazing was experimentally excluded by fencing ten 10×10 m permanent plots within an area that had supported grazing until 2000, by 0.23 sheep ha^?1. Plant and soil microbial communities and physicochemical parameters were monitored within the fenced and unfenced control plots, during three sampling times from 2000 (before the fencing) to 2005. Grazing cessation notably altered the floral composition, with an average dissimilarity of 96.7% between the vegetation communities, over five years. No significant change occurred in the control plots that were grazed throughout the sampling period. This work highlighted that, over a short term, the structural change in the specific plant composition affected only the grass species, confirming that grazing favours the small-sized species over the annual species. Further, it was evident that species groups of conservational and phytogeographic interest, like the endemic and Mediterranean-Atlantic species, tended to disappear with pasture abandonment and were substituted by more widespread species throughout the Mediterranean or even the world. Pasture abandonment was accompanied by an increase of soil pH and a decrease in soil organic matter and soil nitrogen. The microbial parameters recorded at three different sampling times revealed a substantial effect of the plant community, or the time of grazing abandonment, on soil microbial abundance and diversity. Considerable importance is given to the consequences of pasture abandonment on the conservation of plant and microbial diversity and on soil fertility.     

Phytodiversity of temperate permanent grasslands: ecosystem services for agriculture and livestock management for diversity conservation

Plant diversity has been reported to increase productivity. Farming practices aiming at conserving or increasing plant diversity are, however, usually less profitable than conventional ones. In this review, we aim to find reasons for this discrepancy, discuss ecosystem services of grassland phytodiversity that are useful for farmers, and ways of livestock management most beneficial for diversity. Under agricultural conditions, a clear effect of species richness on a site’s primary or secondary production has not yet been demonstrated. Reasons could be that species numbers in permanent grassland are above the threshold of five species found effective in experimental plots or that the conditions are more in equilibrium with management than in weeded experimental plots. Other diversity effects on production stability, nutrient and water retention or product quality might convince farmers to increase diversity. However, these should be tested in agricultural situations, as most research has again been carried out in experimental plots. To enhance phytodiversity, grazing has been found superior over mowing, as selective grazing, treading and excreta deposition increase the heterogeneity of a sward and thus the niches available. Especially rotational grazing with intermediate intensity may be advantageous for phytodiversity. However, complex interactions between environmental conditions, sward composition, management and livestock behaviour make it difficult to forecast grazing effects. Thus, ecological and agricultural researchers should cooperate more, e.g. either in interdisciplinary projects or by hiring researchers from the respective other profession and thus diversifying research groups, in order to integrate agricultural management into biodiversity research and biodiversity measurements into agricultural research to advance our understanding of how to make conservation and enhancement of grassland phytodiversity both feasible and sustainable.     

Platycleis vittata (Orthoptera: Tettigoniidae) in the northwestern part of its range is close to extinction: is this the result of landscape changes?

The northwestern distributions of several steppe species of Orthoptera extend to the southeastern part of the Czech Republic (Pannonia) and occupy more or less isolated fragments of optimal habitats. Their distributional limits are not conditioned by macroclimate in most cases but reflect landscape development (physical structure, plant community type and microclimate) and the insects’ dispersal abilities. These species prefer permanent grassland, and assessment of land use records indicates that the area occupied by permanent grassland has been greatly reduced by agriculture over the last two centuries. The area occupied by permanent grasslands in Pannonia was highest in the nineteenth century, declined until the second half of the twentieth century, and slightly increased at the beginning of the twenty first century. These changes in the area of permanent grassland generally reflect economic and political processes; in particular, consolidation of land plots and expropriation of private property brought an end to grazing. The distribution of a model Orthoptera specialist, Platycleis vittata, on steppe habitats was surveyed at 48 potentially suitable locations from 2004 to 2010. The survey determined that the area with suitable habitat is currently very limited at all 48 locations. Occurrence was confirmed in just two locations that are 3 km apart. The research suggests that Platycleis vittata in the Czech Republic is on the brink of extinction because of extreme fragmentation of suitable biotopes and degradation of optimal habitats.     

Traditional Cattle Grazing in a Mosaic Alkali Landscape: Effects on Grassland Biodiversity along a Moisture Gradient

Extensively managed pastures are of crucial importance in sustaining biodiversity both in local- and landscape-level. Thus, re-introduction of traditional grazing management is a crucial issue in grassland conservation actions worldwide. Traditional grazing with robust cattle breeds in low stocking rates is considered to be especially useful to mimic natural grazing regimes, but well documented case-studies are surprisingly rare on this topic. Our goal was to evaluate the effectiveness of traditional Hungarian Grey cattle grazing as a conservation action in a mosaic alkali landscape. We asked the following questions: (i) How does cattle grazing affect species composition and diversity of the grasslands? (ii) What are the effects of grazing on short-lived and perennial noxious species? (iii) Are there distinct effects of grazing in dry-, mesophilous- and wet grassland types? Vegetation of fenced and grazed plots in a 200-ha sized habitat complex (secondary dry grasslands and pristine mesophilous- and wet alkali grasslands) was sampled from 2006–2009 in East-Hungary. We found higher diversity scores in grazed plots compared to fenced ones in mesophilous- and wet grasslands. Higher cover of noxious species was typical in fenced plots compared to their grazed counterparts in the last year in every studied grassland type. We found an increasing effect of grazing from the dry- towards the wet grassland types. The year-to-year differences also followed similar pattern: the site-dependent effects were the lowest in the dry grassland and an increasing effect was detected along the moisture gradient. We found that extensive Hungarian Grey cattle grazing is an effective tool to suppress noxious species and to create a mosaic vegetation structure, which enables to maintain high species richness in the landscape. Hungarian Grey cattle can feed in open habitats along long moisture gradient, thus in highly mosaic landscapes this breed can be the most suitable livestock type.     

The effects of grassland management and aspect on Orthoptera diversity and abundance: site conditions are as important as management

Calcareous grasslands represent local hotspots of biodiversity in large parts of Central and Northern Europe. They support a great number of rare species which are adapted to these xerothermic habitats. Due to massive changes in land use, calcareous grasslands have become a rare habitat type and their conservation has been given a high priority in the habitats directive of the European Union. It is well known that grassland management may affect biodiversity substantially. However, the quality of calcareous grasslands is also influenced by abiotic conditions, such as aspect (i.e. sun exposure), which affects the local mesoclimate. We studied the combined effects of aspect and grassland management on Orthoptera diversity on 16 sites in Central Germany, in an unbalanced crossed design with three factors: aspect, management type and management intensity. For both response variables (diversity and abundance) we obtained a similar pattern. South-facing pastures maintained a greater diversity than north-facing pastures, but both had a greater diversity than extensively used meadows. Intensively used meadows maintained the lowest diversity and abundances. A multivariate analysis revealed that the abundance of rare Orthoptera species correlated with bare ground cover and forb cover, both of which were greatest at south-facing pastures. Our results suggest that grazing is a more suitable management for maintaining a high biodiversity in calcareous grasslands than mowing. Moreover, the mesoclimate (in this studied measured by its surrogate: aspect) is a crucial factor determining species richness and needs to be considered in reserve planning.     

Biodiversity in agricultural landscapes: different non-crop habitats increase diversity of ground-dwelling beetles (Coleoptera) but support different communities

Agricultural intensification poses a major threat to the conservation of biodiversity and associated ecosystem services. Since non-crop habitats are regarded as important refuges for farmland biodiversity, various greening measures have been proposed to halt biodiversity loss. However, the effectiveness of these measures for biodiversity conservation is still under debate. Therefore, we here compared ground-dwelling beetle (Coleoptera) assemblages of different non-crop habitats (field margins, set-aside fields sown with wildflowers, and permanent grassland fallows) and wheat fields within an intensively used agricultural landscape in western Germany. Taxonomic diversity of Carabidae, Staphylinidae and other coleopteran families and their conservation value were higher in all non-crop habitats than on wheat fields. Surprisingly, though, different types of non-crop habitats did not differ in species richness or the number of threatened species. Thus, field margins and sown wildflower fields were as effective in promoting beetle diversity as grassland fallows. However, different non-crop habitats supported different species assemblages, and several species, in particular especially large ones, were restricted to grassland fallows. These results suggest that different greening measures are effective in promoting the biodiversity of beetles, and that permanent grassland fallows are essential for nature conservation. The fact that habitat types harbored different assemblages stresses the need to combine a variety of greening measures to yield the highest benefit for biodiversity.

     

The important role of scattered trees on the herbaceous diversity of a grazed Mediterranean dehesa

Scattered trees are considered keystone structures and play an important role in Mediterranean sylvopastoral systems. Such systems are associated with high biodiversity and provide important natural resources and ecosystem services. In this study, we measured the contribution of scattered trees and different grazing management (cattle, sheep and wildlife only) to the diversity of the grassland sward in a dehesa (open holm oak woodland) located in Central Spain. We analyzed alpha and beta diversity through measurement of species richness, Shannon-Wiener, and Whittaker indices, respectively; and the floristic composition of the herb layer using subplots within two adjacent plots (trees present vs. trees absent) under three different grazing management regimes, including wildlife only, during a year. We found a 20–30% increment in the alpha diversity of wooded plots, compared to those without trees, regardless of grazing management. All beta indices calculated showed more than 60% species turnover. Wooded plots were occupied by different herbaceous species in different heterogeneous microsites (under the canopy, in the ecotone or on open land) created by the trees. Livestock grazing modified species composition (e.g. more nitrophilous species) compared to wildlife only plots. In addition to all their other benefits, trees are important to maintaining grassland diversity in Mediterranean dehesas.     

Plant species diversity and grazing in the Scandinavian mountains - patterns and processes at different spatial scales

There is a long tradition of grazing by semi‐domestic reindeer and sheep in alpine and sub‐alpine Scandinavian habitats, but present management regimes are questioned from a conservation point of view. In this review we discuss plant diversity patterns in the Scandinavian mountains in a global, regional and local perspective. The main objective was to identify processes that influence diversity at different spatial scales with a particular focus on grazing. In a global perspective the species pool of the Scandinavian mountains is limited. partly reflecting the general latitudinal decline of species but also historical and ecological factors operating after the latest glaciation. At the local scale, both productivity and disturbance are primary factors structuring diversity, but abiotic factors such as soil pH, snow distribution and temperature are also important. Although evidence is scarce, grazing favours local species richness in productive habitats, whereas species richness decreases with grazing when productivity is low. Regional patterns of plant diversity is set by, 1) the species pool. 2) the heterogeneity and fragmentation of communities, and 3) local diversity of each plant community. We suggest that local shifts in community composition depend both on the local grazing frequency and the return‐time of the plant community after a grazing session. In addition, an increasing number of grazing‐modified local patches homogenises the vegetation and is likely to reduce the regional plant diversity. The time scale of local shifts in community composition depends on plant colonisation and persistence, From a mechanistic point of view, diversity patterns at a regional scale also depend on the regional dynamics of single species. Colonisation is usually a slow and irregular process in alpine environments, whereas the capacity for extended local persistence is generally high. Although the poor knowledge of plant regional dynamics restricts our understanding of how grazing influences plant diversity, we conclude that grazing is a key process for maintaining biodiversity in the Scandinavian mountains.     

Effects of long‐term grazing management on sand dune vegetation of high conservation interest

Question: Can long‐term grazing management maintain and restore species‐rich sand dune plant communities within a sand dune site of high conservation interest? Location: Newborough Warren, North Wales, UK. Methods: Vegetation changes that occurred between 1987 and 2003, subsequent to grazing by domestic livestock being introduced to the site after decades with little or no stock grazing, were analysed using data collected from permanent monitoring quadrats over a 16‐year period. Results: At the plant community level, grazing brought about a shift from a tall‐grass dominated, species‐poor community to a more species‐rich community in the dry dunes, but did not change community type in dune slacks. However, at the species level, grazing enhanced the abundance of some desired perennial, annual and biennial species, graminoids and bryophytes in both habitat types. The increased frequency of positive indicator species for habitat condition suggests that grazing was beneficial for species of conservation interest. Ellenberg nitrogen (N) values decreased after grazing in dry habitats but showed no long‐term change independent of grazing, suggesting no increase in site fertility over the study period. Surprisingly, light (L) values also decreased in the dry dunes after grazing. Conclusions: Long‐term grazing management can play an important role for the conservation of dune communities and associated species. Because of its positive effects on species diversity, plant communities and habitat condition in sand dunes, livestock grazing is recommended for conservation management.     

Diversity and floristic patterns of mediterranean grasslands: the relative influence of environmental and land management factors

Managed grasslands are normally ecosystems with high species diversity. They are associated with traditional extensive livestock grazing. Land-use changes, in particular gradual abandonment or grazing intensification, lead to major changes in floristic patterns of these grasslands, some included in priority habitats of the EU Habitats Directive. In order to analyse these patterns of change, Mediterranean grasslands of eastern areas of mainland Portugal were studied aiming to: (1) establish ecological gradients underlying their floristic patterns; (2) examine the relative importance of both environmental and land-use factors on their floristic composition; (3) assess how floristic composition and species richness are affected by land-use factors. Vegetation sampling was carried out from 2008 to 2009 following phytosociological procedures. Canonical Correspondence Analysis was applied. Variation partitioning was used to assess the relative influence of land-use variables. Richness, legumes cover, endemic species and bryophytes cover were compared in four land-management regimes: unmanaged; extensive grazing by sheep; extensive grazing by cattle and sheep; frequent soil tillage. Significant differences were found in floristic and diversity patterns, revealing the importance of grazing as a management tool for maintaining or improving floristic diversity. From our findings slight extensive grazing can contribute to both maintenance of species diversity and to the increase in legumes cover and thus to palatability and economic value of studied grasslands. Interactions between herbivores and grasslands, considering also their influences on soil properties, have an important role in the equilibrium states which promote biodiversity and conservation of the services of these ecosystems.     

Biodiversity of soil macrofauna in the New Forest: a benchmark study across a national park landscape

The New Forest National Park is a hotspot for biodiversity in the UK. A long history of grazing by ponies in the New Forest landscape has created a diverse mosaic of habitats that are of international significance. We investigated patterns of species diversity and composition across the New Forest landscape by sampling soil, leaf litter and ground macrofauna from woodland, grassland and heathland plots across the entire landscape. We used a spatially replicated design of hand sorted soil pits, Winkler extraction of leaf litter, and pitfall traps. We concentrated on diversity patterns of the following target groups: Coleoptera, Formicidae, Isopoda, Chilopoda, Diplopoda, Opiliones and Lumbricidae. The most striking difference in species assemblages is between wooded and open areas. Woodlands are the most diverse habitats and have a distinct assemblage, largely due to those leaf litter invertebrate species which are only present under a closed canopy. Open areas are less diverse, with diversity particularly low in the wet grasslands. However, the open areas do have a distinct fauna, especially in the wet and dry heaths which are home to a number of rare species, particularly of Formicidae. We discuss the potential conservation problems facing the New Forest and how these might affect soil macrofauna biodiversity in the future and conclude that climate change; over-grazing; and land use changes represent the largest threats. Although a relatively stable landscape which benefits from protection under UK law, changes in grazing intensity or management practices in the New Forest, particularly for some of the habitats of European importance (e.g. wet heathlands), could negatively affect soil macrofauna biodiversity. Climate change may also exacerbate biodiversity decline as a result of increased grazing intensity or changes in management.     

Pollinator behavioural responses to grazing intensity

It has been suggested that intensive grazing management, aimed at maintaining plant diversity, might not be the optimal choice to preserve diversity of insects in semi-natural pastures. In the present study the behaviour of flower visiting insects was studied in two semi-natural pastures in central Sweden. Two grazing treatments were established with one grazed from mid-May, “continuous”, and one grazed from mid-July, “late”. Flower visitors were followed for 9 weeks in summer 2003 in 7 pairs of 5 × 5 m plots on two sides of a fence dividing the two grazing treatments. Visitor behaviour was studied on three decision levels between: (1) habitats, (2) flowers and (3) activities on flowers. The pattern varied between decision levels: More species and individual visitors chose to forage in the late grazing treatment. Visitation rate and flower constancy did not differ between treatments and was related, to a large extent, to plant species richness. In relation to flowers, insects utilized a broader diversity of activities in the late grazing treatment. All patterns were consistent across sites and during the whole study period. The differences in pollinator abundance and activities on flowers were best explained by the higher abundance of flowers. It is suggested that studies of insect behaviour may be a useful tool when deciding on management recommendations. Late grazing is recommended as a useful management regime and might potentially function as a substitute for mowing in the future.     

Are cladoceran diversity and community structure linked to spatial heterogeneity in urban landscapes and pond environments?

Biodiversity patterns in cladoceran communities were investigated in urban waterbodies in relation with residential land use, pond management, and waterbody environments. We evaluated species richness in the pelagic and littoral zones of eighteen waterbodies of a large Canadian city. Gamma diversity (26 species) observed at a small scale in the urban survey was important comparatively to large-scale surveys of lakes. Beta diversity ranged from 1 to 8 species among waterbodies. We tested if littoral species greatly contributed to regional diversity in urban waterbodies. Littoral species (Chydoridae, Ilyocryptidae, Macrothricidae, Polyphemidae) accounted for 58% of the total species pool. We distinguished five cladoceran assemblages associated to different waterbodies (temporary ponds, permanent lakes, and wetlands). Cladoceran communities were more diverse and variable in permanent lakes than in temporary ponds. Changes in cladoceran species assemblages among waterbodies were driven by variations in waterbody size and phosphorus enrichment, macrophyte and algal biomass, urban density, pond management practices, and the presence of potential predators as fish and macroinvertebrates. Our study indicates that both artificial ponds and lakes and natural wetlands are valuable habitats for the conservation of cladoceran biodiversity and rare endemic species in urban regions. Further research on pond management strategies promoting urban aquatic biodiversity should be undertaken.     

The rehabilitation value of a small culturally significant island based on the arthropod natural capital

Small islands are particularly vulnerable to degradation by invasive species and often lack source populations to replace those lost during localized extinctions. Robben Island, a significant South African cultural heritage site, has a long history of anthropogenic impact. Introduced alien mammals and trees have resulted in numerous localized plant extinctions with their impact on arthropod biodiversity remaining unclear. We used Robben Island’s arthropod fauna as focal group to investigate the rehabilitation potential of this transformed island. Ground surface-living, foliage-inhabiting and flower-visiting arthropods were collected using five sampling techniques. Arthropod diversity was highest in the two ‘natural’ habitats compared to alien Eucalyptus plantations. Arthropod compositional diversity differed significantly between alien plantations and natural habitats. Nevertheless, a remarkable 17 % of all species were confined to plantations. However, when we corrected for the effect of rarity, only 15 species (4 %) were unique to alien plantations and all those identified to species level were either alien in origin or were widespread generalists only normally associated with transformed areas. This emphasizes the need to identify species that drive similarity indices to fully comprehend the conservation value of alien vegetation. Arthropods found in the remaining natural vegetation showed remarkable tolerance of long-term grazing pressures from introduced alien mammals. Only eight Orthoptera species were sampled, yet one was a rediscovery of a rare species and another a range extension. All indigenous species showed strong preferences for natural habitats. Thus, Robben Island could still hold conservation value if the natural habitats are rehabilitated and the Eucalyptus plantations removed.     

Threatened inland sand vegetation in the temperate zone under different types of abiotic and biotic disturbances during a ten-year period

In sandy grassland vegetation of Central Europe, extensive grazing is often a management tool to maintain and improve nature conservation value. As part of a long-term field experiment lasting 10 years we investigated the effects of sheep grazing as a type of moderate disturbance. As “experiments by nature” happened in this time period we were also able to study severe biotic (rabbit grazing) and abiotic (drought) disturbances, examining the recovery and resilience of the system after these severe disturbances.Within a six-fold replicated randomised split-plot design, 25-m² plots of Armerio-Festucetum trachyphyllae vegetation were studied from 2000 to 2009 in the northern upper Rhine valley (Germany). We analysed sheep-grazed and non-grazed plots (both with very low rabbit impact until the first half of 2005). In 2005 we established an additional plot type without rabbit and sheep grazing. Severe rabbit impact was studied in detail from 2006 to 2008 concerning flower resources, seed production, endozoochorous seed dispersal and phytomass extraction. Data were analysed by ordination methods and mixed linear models.In times of low rabbit densities moderate disturbance by sheep grazing maintained species diversity. Severe drought in 2003 resulted in a marked decrease of species numbers, but the system recovered already in 2004. The subsequently analysed “high rabbit impact” resulted in decreases of species numbers, cover of bryophytes, flower quantities and seed content in faeces. Species numbers also declined on plots without rabbit grazing, but for different reasons. Shifts in phenological phases due to rabbit grazing were not observed, but the sum of flowers and number of flowering species decreased. After the decline of the rabbit population, species numbers slightly increased in 2009. Non-grazed plots showed an increase of litter.Despite severe disturbances by rabbits or drought, the community structure was relatively stable, especially in case of non-ruderalised plots and showed only slight changes. We developed a conceptual model, showing the high potential of recovery and resilience even in the case of severe disturbances.     

Does natural reforestation represent a potential threat to dung beetle diversity in the Alps?

Traditional agro-pastoral practices are in decline over much of the Alps, resulting in the complete elimination of livestock grazing in some areas. Natural reforestation following pastoral abandonment may represent a significant threat to alpine biodiversity, especially that associated with open habitats. This study presents the first assessment of the potential effects of natural reforestation on dung beetles by exploring the relationships between the beetle community (abundance, diversity, species turnover and assemblage structure) and the vegetation stages of ecological succession following pastoral abandonment. A hierarchical sampling design was used in the montane belt of the Sessera Valley (north-western Italian Alps). Dung beetles were sampled across 16 sampling sites set in four habitat types corresponding to four different successional stages (pasture, shrub, pioneer forest and beech forest) at two altitudinal levels. The two habitats at the extremes of the ecological succession, i.e. pasture and beech forest, had the greatest effect on the structure of local dung beetle assemblages. Overall, dung beetle abundance was greater in beech forest, whereas species richness, Shannon diversity and taxonomic diversity were significantly higher in pasture, hence suggesting this latter habitat can be considered as a key conservation habitat. Forests and pastures shared a lower number of species than the other pairs of habitats (i.e. species turnover between these two habitats was the highest). The two intermediate seral stages, i.e. shrub and pioneer forest, showed low dung beetle abundance and diversity values. Local dung beetle assemblages were also dependent on season and altitude; early-arriving species were typical of pastures of high elevation, whereas late-arriving species were typical of beech forests. It is likely that grazing in the Alps will continue to decrease in the future leading to replacement of open habitats by forest. This study suggests therefore that, at least in the montane belt, reforestation may have potentially profound and negative effects on dung beetle diversity. Maintaining traditional pastoral activities appears to be the most promising approach to preserve open habitats and adjacent beech forests, resulting in the conservation of species of both habitats.     

Plant community ecology of Pinus sylvestris, an extirpated species reintroduced to Ireland

Plantation forests can make a significant contribution to the conservation of native biodiversity, especially where native forest cover is low. Ireland is used as a case study to explore the contribution to biodiversity made by stands of Pinus sylvestris (Scots pine), a reintroduced species. Despite its disputed native status, P. sylvestris is being widely planted in semi-natural habitats in Ireland. The associated vegetation communities have not previously been described and their conservation value is unknown. Baseline information is needed to inform conservation and forest management strategies. Botanical surveys were carried out at 20 plots of P. sylvestris-dominated woodland and scrub throughout the Republic of Ireland. Vegetation, structural and environmental data were recorded. Data were analysed using non-parametric and multivariate statistical techniques and a synoptic table was prepared. P. sylvestris was found to be a non-specialist in terms of its environmental tolerances. β diversity among plots was high while α diversity within plots was low to moderate. The plots surveyed contained 14.2% of the Irish native flora. There was a low level of constancy of species. Four reasonably well defined vegetation communities were identified. Soil pH, altitude and slope had important roles in partitioning these vegetation types and soil pH was positively correlated with species richness. P. sylvestris is well established, well integrated and naturalising in Irish semi-natural habitats. Some of the associated vegetation communities corresponded to habitats of international conservation importance. This research demonstrates that stands of P. sylvestris represent an important resource for Ireland’s native botanical and habitat diversity.