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The treeline ecotone divides forest from open alpine or arctic vegetation states. Treelines are generally perceived to be temperature limited. The role of herbivores in limiting the treeline is more controversial, as experimental evidence from relevant large scales is lacking. Here we quantify the impact of different experimentally controlled herbivore densities on the recruitment and survival of birch Betula pubescens tortuosa along an altitudinal gradient in the mountains of southern Norway. After eight years of summer grazing in large-scale enclosures at densities of 0, 25, and 80 sheep/km 2 , birch recruited within the whole altitudinal range of ungrazed enclosures, but recruitment was rarer in enclosures with low-density sheep and was largely limited to within the treeline in enclosures with high-density sheep. In contrast, the distribution of saplings (birch older than the experiment) did not differ between grazing treatments, suggesting that grazing sheep primarily limit the establishment of new tree recruits rather than decrease the survival of existing individuals. This study provides direct experimental evidence that herbivores can limit the treeline below its potential at the landscape scale and even at low herbivore densities in this climatic zone. Land use changes should thus be considered in addition to climatic changes as potential drivers of ecotone shifts.

Vegetation at ecotone transitions between open and forested areas is often heavily affected by two key processes: climate change and management of large herbivore densities. These both drive woody plant state shifts, determining the location and the nature of the limit between open and tree or shrub-dominated landscapes. In order to adapt management to prevailing and future climate, we need to understand how browsing and climatic factors together affect the growth of plants at biome borders. To disentangle herbivory and climate effects, we combined long-term tree growth monitoring and dendroecology to investigate woody plant growth under different temperatures and red deer (Cervus elaphus) herbivory pressures at forest–moorland ecotones in the Scottish highlands. Reforestation and deer densities are core and conflicting management concerns in the area, and there is an urgent need for additional knowledge. We found that deer herbivory and climate had significant and interactive effects on tree growth: in the presence of red deer, pine (Pinus sylvestris) growth responded more strongly to annual temperature than in the absence of deer, possibly reflecting differing plant–plant competition and facilitation conditions. As expected, pine growth was negatively related to deer density and positively to temperature. However, at the tree population level, warming decreased growth when more than 60% of shoots were browsed. Heather (Calluna vulgaris) growth was negatively related to temperature and the direction of the response to deer switched from negative to positive when mean annual temperatures fell below 6.0°C. In addition, our models allow estimates to be made of how woody plant growth responds under specific combinations of temperature and herbivory, and show how deer management can be adapted to predicted climatic changes in order to more effectively achieve reforestation goals. Our results support the hypothesis that temperature and herbivory have interactive effects on woody plant growth, and thus accounting for just one of these two factors is insufficient for understanding plant growth mechanics at biome transitions. Furthermore, we show that climate-driven woody plant growth increases can be negated by herbivory.

Wildfire is an increasingly significant disturbance in temperate uplands, yet its long‐term impacts on vegetation remain poorly understood. In Scotland, UK, where blanket bogs and heathlands dominated by Calluna vulgaris are widespread, we investigated how wildfire affects vegetation composition and diversity, what the recovery time scales are, and which taxa are most vulnerable. To address these questions, we conducted a space‐for‐time substitution survey across 27 wildfire sites, spanning 2–24 years since fire. Cover of individual plant species and lichens and data on soil carbon, nitrogen, and pH were collected in burnt and adjacent unburnt areas, with fire severity assessed using remote sensing. Regression models were used to examine Shannon diversity, heterogeneity, and compositional dissimilarity between burnt and unburnt areas over time. Effects on community composition were assessed using Canonical Correspondence Analysis (CCA) and Non‐Metric Multidimensional Scaling (NMDS). Our results indicate that wildfire severity and habitat play crucial roles in shaping post‐fire vegetation dynamics. Blanket bog and wet heathland displayed resistance to severe burning, with mild effects on vegetation composition. Dry heathland experienced stronger initial impacts but demonstrated significant recovery over time. Vegetation composition resembled adjacent unburnt areas in approximately 20–25 years following low‐severity fire, and higher‐severity fires prolonged regeneration times. Wildfire reduced Shannon diversity in dry moorland but increased it in wet moorland, with no effect of time since fire. Plot heterogeneity increased with fire severity and also showed no temporal trend. Sphagnum abundance showed little relationship with time since fire and may contribute to the resilience of wet moorlands to severe fire. Lichens and pleurocarpous mosses were reduced in cover, whereas graminoids and acrocarpous mosses were abundant in recently burnt areas. The increased risks and consequences of wildfire under climate change may be most severely felt on dry moorland habitats. Although wet moorlands are currently resilient, ongoing management is crucial as future conditions may increase their susceptibility to fire and vegetation change. This study examines wildfire impacts on vegetation composition and diversity across 27 Scottish blanket bog and heathland sites spanning 2–24 years since fire. Vegetation change and recovery were strongly influenced by habitat type and fire severity, with wet moorlands showing resistance to severe burning and dry heathlands experiencing greater initial impacts but eventual recovery. The findings highlight the vulnerability of dry moorlands under climate change and suggest that, although wet peatlands are currently resilient, ongoing management is crucial as future conditions may increase their susceptibility to severe fire and vegetation change.

With the species composition and/or functioning of many ecosystems currently changing due to anthropogenic drivers it is important to understand and, ideally, predict how changes in one part of the ecosystem will affect another. Here we assess if vegetation composition or soil chemistry best predicts the soil microbial community. The above and below-ground communities and soil chemical properties along a successional gradient from dwarf shrubland (moorland) to deciduous woodland (Betula dominated) were studied. The vegetation and soil chemistry were recorded and the soil microbial community (SMC) assessed using Phospholipid Fatty Acid Extraction (PLFA) and Multiplex Terminal Restriction Fragment Length Polymorphism (M-TRFLP). Vegetation composition and soil chemistry were used to predict the SMC using Co-Correspondence analysis and Canonical Correspondence Analysis and the predictive power of the two analyses compared. The vegetation composition predicted the soil microbial community at least as well as the soil chemical data. Removing rare plant species from the data set did not improve the predictive power of the vegetation data. The predictive power of the soil chemistry improved when only selected soil variables were used, but which soil variables gave the best prediction varied between the different soil microbial communities being studied (PLFA or bacterial/fungal/archaeal TRFLP). Vegetation composition may represent a more stable ‘summary' of the effects of multiple drivers over time and may thus be a better predictor of the soil microbial community than one-off measurements of soil properties.

1. Planning for nature conservation has increasingly emphasised the concepts of resilience and spatial networks. Although the importance of habitat networks for individual species is clear, their significance for long-term ecological resilience and multi-species conservation strategies is less established. 2. Referencing spatial network theory, we describe the conceptual basis for defining and assessing a network of wildlife areas that supports species' resilience to multiple forms of perturbations and pressures. We explore actions that could enhance network resilience at a range of scales, based on ecological principles, with reference to four well-established strategies for intervention in a spatial network (\"Better, Bigger, More and Joined\") from the influential Making Space for Nature report by Lawton et al. (2010). 3. Building existing theory into useable and scalable approaches applicable to large numbers of species is challenging but tractable. We illustrate the policy context, describe the elements of a long-term adaptive management plan and provide example actions, metrics and targets for early implementation using England as a case study, where there is an opportunity to include large-scale ecological planning in a newly launched 25-year environment plan. 4. Policy implications. The concept of resilient ecological networks has attracted sc entific and political support, but there is no consensus on what a resilient network would look like, or how to assess it. Therefore, it is unclear whether existing targets for action will be sufficient to achieve network resilience. We show that the scientific principles to place resilience and network theory at the heart of largescale and long-term environmental planning are established and ready to implement in practice. Delivering a resilient network to support nature recovery is achievable and can be integrated with ongoing conservation actions and targets, by assessing their effectiveness on properties of the entire network. England's 25 Year Environment Plan promises to deliver a natural environment that is protected and enhanced for the future and so provides the ideal testbed.

Browsing by cervids plays a key role in structuring forest ecosystems and dynamics. Many boreal forest systems are managed for timber resources, and at the same time the wild cervid populations are also harvested. Thus, the determination of sustainable densities of cervids for the purpose of forest and game management is challenging. In this study we report on a red deer (Cervus elaphus) exclosure experiment in the mature forests of Western Norway. Ten pairs of exclosures and browsed plots were initiated in 2008. The rate of browsing and height growth of marked individuals was recorded annually, and the total densities of all tree species assessed over the following 4 y. We found that height growth of rowan (Sorbus aucuparia) saplings (1 m tall), the most numerous tree species at the site, was prevented when 20% of the shoots were browsed. Outside of the exclosures, net height growth of rowan saplings tended to be positive when trees were below 40 cm in height, but growth was constrained in rowan saplings over this height. The density of rowan also increased in both treatments, showing that recruitment was occurring, but the increase was greater where browsed than in the exclosure. The increase in density of rowan, combined with the curtailment of height growth in the presence of red deer, serves to create a carpet of short stature rowan saplings. This has parallels with the browsing lawn concept, but it seems to occur in interaction with snow depth; individuals protruding above the snow layer are likely to be browsed during the winter, whilst smaller individuals are protected during this season, when browsing is at its peak.

1. Wild large herbivores provide goods and income to rural communities, have major impacts on land use and habitats of conservation importance and, in some cases, face local or global extinction. As a result, substantial effort is applied to their management across the globe. To be effective, however, management has to be science-based. We reviewed recent fundamental and applied studies of large herbivores with particular emphasis on the relationship between the spatial and temporal scales of ecosystem response, management decision and implementation. 2. Long-term population dynamics research has revealed fundamental differences in how sex/age classes are affected by changes in density and weather. Consequently, management must be tailored to the age and sex structure of the population, rather than to simple population counts. 3. Herbivory by large ungulates shapes the structure, diversity and functioning of most terrestrial ecosystems. Recent research has shown that fundamental herbivore/vegetation interactions driving landscape change are localized, often at scales of a few metres. For example, sheep and deer will selectively browse heather Calluna vulgaris at the edge of preferred grass patches in heather moorland. As heather is vulnerable to heavy defoliation, in the long term this can lead to loss of heather cover despite the average utilization rate of heather in a management area being low. Therefore, while herbivore population management requires a large-scale approach, management of herbivore impacts on vegetation may require a much more flexible and site-specific approach. 4. Localized impacts on vegetation have cascading effects on biodiversity, because changes in vegetation structure and composition, induced by large herbivores affect habitat suitability for many other species. As such, grazing should be considered as a tool for broader biodiversity management requiring a more sophisticated approach than just, for example, eliminating grazing from conservation areas through the use of exclosures. 5. Synthesis and applications. The management of wild large herbivores must consider different spatial scales, from small patches of vegetation to boundaries of an animal population. It also requires long-term planning based on a deep understanding of how population processes, such a birth rate, death rate and age structure, are affected by changes in land use and climate and how these affect localized herbivore impacts. Because wild herbivores do not observe administrative or political boundaries, adjusting their management to socio-political realities can present a challenge. Many developing countries have established co-operative management groups that allow all interested parties to be involved in the development of management plans; developed countries have a lot to learn from the developing world's example.

Questions: Is there evidence for biotic homogenization of upland vegetation? Do the magnitude and nature of floristic and compositional change vary between vegetation types? What can be inferred about the drivers responsible for the observed changes? Location: Upland heath, mire and grassland communities of the northwest Highlands of Scotland, UK. Methods: We re-survey plots first described in a phytosociological study of 1956—1958 to assess the changes in plant species composition over the last 50 yr in five major upland vegetation types. Using a combination of multivariate analysis, dissimilarity measures, diversity metrics and published data on species attributes; we quantify, characterize and link potential drivers of environmental change with the observed changes in species composition. Results: Grassland and heath vegetation declined in species richness and variation in community composition, while mires showed little change. Previously distinct vegetation types became more similar in composition, characterized by the increased dominance of generalist upland graminoids and reduced dwarfshrub, forb and lichen cover, although novel assemblages were not apparent. Species with an oceanic distribution increased at the expense of those with an arctic-montane distribution. Temperature, precipitation and acidity were found to be potentially important in explaining changes in species composition: species that had undergone the greatest increases had a preference for warmer, drier and more acidic conditions. Conclusions: The vegetation of the northwest Scottish Highlands has undergone marked biotic homogenization over the last 50 yr, manifested through a loss of various aspects of diversity at the local, community and landscape scales. The magnitude of change varies between vegetation types, although the nature of change shows many similar characteristics. Analyses of species attributes suggest these changes are driven by climate warming and acidification, although over-grazing may also be important. This study highlights the importance of the link between the loss of plant diversity and homogenization at multiple scales, and demonstrates that boreal heath communities are particularly at risk from these processes.

1. Disturbance is one of the most important factors structuring the taxonomic and functional composition of vegetation. Vegetation resistance or resilience to disturbance depends on local environmental conditions, further modifying the pool of species and traits. This paper aims to understand how disturbance and local environment combine to affect the resistance and resilience of vegetation. 2. A functional-trait approach was used to detect traits related to vegetation resistance and resilience, and trait attributes of individual species responding to disturbance. Trait approaches enable comparison of vegetation responses across biogeographic regions containing different species pools. 3. At 35 European forest and grassland sites, experimental disturbance (human trampling) was applied at five intensities. Indices for resistance and resilience were calculated, based on total vegetation cover, and related to climate and local site factors. Additional indices were calculated for the most common species to demonstrate traits that confer resistance and resilience to disturbance. 4. Vegetation resistance was related to occurrence of species with traits selected by a history of intensive land use (smaller leaf size, rosette plant form) and local environmental conditions. Vegetation resilience, however, was associated with ecosystem properties that facilitate higher growth rates. Resilient vegetation occurred where irradiation was higher (grasslands, open forests) with sufficient water availability (summer precipitation, humidity) and comprised of species with traits related to enhanced growth rates (increased specific leaf area, decreased leaf dry matter content). 5. Synthesis. This pan-European disturbance experiment demonstrates that different drivers (land use or climate) of vegetation response show different mechanistic responses to physical disturbance. Resistance depends on the functional composition of predominant species in the assemblage, which is strongly affected by land-use history; resilience is directly connected to growth rates affected by climate. We argue for the inclusion of land-use history and climate into the planning process for visitor management, especially in areas of high conservation interest.

The need for policy makers to understand science and for scientists to understand policy processes is widely recognised. However, the science-policy relationship is sometimes difficult and occasionally dysfunctional; it is also increasingly visible, because it must deal with contentious issues, or itself becomes a matter of public controversy, or both. We suggest that identifying key unanswered questions on the relationship between science and policy will catalyse and focus research in this field. To identify these questions, a collaborative procedure was employed with 52 participants selected to cover a wide range of experience in both science and policy, including people from government, non-governmental organisations, academia and industry. These participants consulted with colleagues and submitted 239 questions. An initial round of voting was followed by a workshop in which 40 of the most important questions were identified by further discussion and voting. The resulting list includes questions about the effectiveness of science-based decision-making structures; the nature and legitimacy of expertise; the consequences of changes such as increasing transparency; choices among different sources of evidence; the implications of new means of characterising and representing uncertainties; and ways in which policy and political processes affect what counts as authoritative evidence. We expect this exercise to identify important theoretical questions and to help improve the mutual understanding and effectiveness of those working at the interface of science and policy.