Search

Developing a holistic understanding of the ecosystem impacts of global change requires methods that can quantify the interactions among multiple response variables. One approach is to generate high dimensional spaces, or hypervolumes, to answer ecological questions in a multivariate context. A range of statistical methods has been applied to construct hypervolumes but have not yet been applied in the context of ecological data sets with spatial or temporal structure, for example, where the data are nested or demonstrate temporal autocorrelation. We outline an approach to account for data structure in quantifying hypervolumes based on the multivariate normal distribution by including random effects. Using simulated data, we show that failing to account for structure in data can lead to biased estimates of hypervolume properties in certain contexts. We then illustrate the utility of these "model-based hypervolumes" in providing new insights into a case study of afforestation effects on ecosystem properties where the data has a nested structure. We demonstrate that the model-based generalization allows hypervolumes to be applied to a wide range of ecological data sets and questions., (© 2019 The Authors. Ecology published by Wiley Periodicals, Inc. on behalf of Ecological Society of America.)

A primary requirement for policy objectives is reliable figures on the composition of any region. Currently there is no comprehensive, definitive set of statistics for the British Uplands, hence the present paper. An overview of the background to the region is first provided, together with some examples of the available figures and a discussion of their limitations. The paper uses a formal structure, with landscapes at the highest level followed by habitats, then vegetation, and finally species, with exact definitions of the categories applied at all levels. The figures are produced from a survey of stratified, random one kilometre squares. The tables give comprehensive figures for Great Britain (GB) as a whole, and also England, Wales and Scotland.

The paper demonstrates that the British Uplands have been influenced to a great extent by policy - for example, the planting of almost a million hectares of exotic conifers since the Second World War, and the extent of designated areas. Otherwise, climate change transcends policy and is locally important to coastal and high mountain habitats. The different policies affecting the Uplands, such as the Common Agricultural Policy, are described, as are the wide range of designations such as National Parks, which may have a stabilising effect in times of great change. A new trend has started in Scotland in the last 20 years of local initiatives, such as the community ownership of Eigg, however large landowners still dominate. An impact table is presented of the habitats that make up the Uplands and their links to driving forces, with potential changes described that are likely to take place under future policies such as Brexit. Dwarf shrub heath is the habitat affected by many management drivers, whereas habitats such as Inland Rock, are relatively stable but most likely to be affected by climate change.

The majority of forest cover in the British Uplands had been lost by the beginning of the Nineteenth Century, because of felling followed by overgrazing by sheep and deer. The situation remained unchanged until a government policy of afforestation, mainly by exotic conifers, after the First World War up to the present day. This paper analyses the distribution of these predominantly coniferous plantations, and shows how they occupy specific parts of upland landscapes in different zones throughout Britain Whilst some landscapes are dominated by these new forests, elsewhere the blocks of trees are more localised. Although these forests virtually eliminate native ground vegetation, except in rides and unplanted land, the major negative impacts are at the landscape level. For example, drainage systems are altered and ancient cultural landscape patterns are destroyed. These impacts are summarised and possible ways of amelioration are discussed. By contrast, in recent years, a series of projects have been set up to restore native forest cover, as opposed to the extensive plantations of exotic species. Accordingly, the paper then provides three examples of such initiatives designed to restore native forests to otherwise bare landscapes, as well as setting them into a policy context. Whilst such projects cover a limited proportion of the British Uplands they nevertheless restore forest to landscapes at a local level.

The Countryside Survey (CS) of Great Britain (GB) provides a unique and statistically robust series of datasets, consisting of an extensive set of repeated ecological measurements at a national scale, covering a time span of 29 years. CS was first undertaken in 1978 to provide a baseline for ecological and land use change monitoring in the rural environment of GB, following a stratified random design, based on 1 km squares. Originally, eight random 1 km squares were drawn from each of 32 environmental classes, thus comprising 256 sample squares in the 1978 survey. The number of these sites increased to 382 in 1984, 506 in 1990, 569 in 1998 and 591 in 2007. Detailed information regarding vegetation types and land use was mapped in all five surveys, allowing reporting by defined standard habitat classifications. Additionally, point and linear landscape features (such as trees and hedgerows) are available from all surveys after 1978. From these stratified, randomly located sample squares, information can be converted into national estimates, with associated error terms. Other data, relating to soils, freshwater and vegetation, were also sampled on analogous dates. However, the present paper describes only the surveys of landscape features and habitats. The resulting datasets provide a unique, comprehensive, quantitative ecological coverage of extent and change in these features in GB. Basic results are presented and their implications discussed. However, much opportunity for further analyses remains. [ABSTRACT FROM AUTHOR]

Atmospheric nitrogen (N) deposition has had detrimental effects on species composition in a range of sensitive habitats, although N deposition can also increase agricultural productivity and carbon storage, and favours a few species considered of importance for conservation. Conservation targets are multiple, and increasingly incorporate services derived from nature as well as concepts of intrinsic value. Priorities vary. How then should changes in a set of species caused by drivers such as N deposition be assessed? We used a novel combination of qualitative semi-structured interviews and quantitative ranking to elucidate the views of conservation professionals specialising in grasslands, heathlands and mires. Although conservation management goals are varied, terrestrial habitat quality is mainly assessed by these specialists on the basis of plant species, since these are readily observed. The presence and abundance of plant species that are scarce, or have important functional roles, emerged as important criteria for judging overall habitat quality. However, species defined as ‘positive indicator-species’ (not particularly scarce, but distinctive for the habitat) were considered particularly important. Scarce species are by definition not always found, and the presence of functionally important species is not a sufficient indicator of site quality. Habitat quality as assessed by the key informants was rank-correlated with the number of positive indicator-species present at a site for seven of the nine habitat classes assessed. Other metrics such as species-richness or a metric of scarcity were inconsistently or not correlated with the specialists’ assessments. We recommend that metrics of habitat quality used to assess N pollution impacts are based on the occurrence of, or habitat-suitability for, distinctive species. Metrics of this type are likely to be widely applicable for assessing habitat change in response to different drivers. The novel combined qualitative and quantitative approach taken to elucidate the priorities of conservation professionals could be usefully applied in other contexts. [ABSTRACT FROM AUTHOR]

1. Although invasions by alien plants are major threats to the biodiversity of natural habitats, individual habitats vary considerably in their susceptibility to invasion. Therefore the risk assessment procedures, which are used increasingly by environmental managers to inform effective planning of invasive plant control, require reliable quantitative information on the extent to which different habitats are susceptible to invasion. It is also important to know whether the levels of invasion in different habitats are locally specific or consistent among regions with contrasting climate, flora and history of human impact. 2. We compiled a database of 52 480 vegetation plots from three regions of Europe: Catalonia (Mediterranean–submediterranean region), Czech Republic (subcontinental) and Great Britain (oceanic). We classified plant species into neophytes, archaeophytes and natives, and calculated the proportion of each group in 33 habitats described by the European Nature Information System (EUNIS) classification. 3. Of 545 alien species found in the plots, only eight occurred in all three regions. Despite this large difference in species composition, patterns of habitat invasions were highly consistent between regions. None or few aliens were found in environmentally extreme and nutrient-poor habitats, e.g. mires, heathlands and high-mountain grasslands. Many aliens were found in frequently disturbed habitats with fluctuating nutrient availability, e.g. in man-made habitats. Neophytes were also often found in coastal, littoral and riverine habitats. 4. Neophytes were found commonly in habitats also occupied by archaeophytes. Thus, the number of archaeophytes can be considered as a good predictor of the neophyte invasion risk. However, neophytes had stronger affinity to wet habitats and disturbed woody vegetation while archaeophytes tended to be more common in dry to mesic open habitats. 5. Synthesis and applications. The considerable inter-regional consistency of the habitat invasion patterns suggests that habitats can be used as a good predictor for the invasion risk assessment. This finding opens promising perspectives for the use of spatially explicit information on habitats, including scenarios of future land-use change, to identify the areas of highest risk of invasion. [ABSTRACT FROM AUTHOR]