Robust tools are needed to prioritise the management of invasive non-native species
Probably in response to recent changes in habitat structure, populations of a number of species of deer are increasing both in numbers and in geographical distribution in lowland Britain. In the wake of this expansion there is increasing awareness and concern over damage to agriculture/horticulture and forestry, as well as damage to sensitive vegetation in conservation areas. Despite a perception that damage levels are rising, data that actually quantify the scale of impact by deer on lowland agriculture and forestry interests or conservation habitats are scarce. This review attempts to draw together such objective data as are available to assess more formally the actual impact of deer damage in these different contexts and the economic significance of damage caused. The review concludes with a brief consideration of implications for management. The majority of agricultural damage reported in England and Wales was due to Fallow, Red and Roe Deer; Muntjac were only implicated in a little horticultural damage where they are numerous. Most reports were of damage to pasture or cereals, with oilseed rape, nursery and orchard crops also frequently damaged. Because of fundamental differences in ecology and distribution, different species of deer were implicated in different types of damage, depending on feeding habit and distribution in relation to geographical patterns of crop‐type. In a woodland context, Fallow, Red and Roe Deer were implicated in the majority of reported damage in lowland UK, which is most frequent in the north of England and lowest in Wales. Despite the apparent severity of damage caused to agriculture or forestry, the actual economic significance of such damage would appear in many cases to be negligible or small. Field crops frequently recover completely from such damage, and although woodland crops may be checked and quality of the timber may be reduced as a consequence of earlier browsing damage, losses may be far less than they first appear. This whole question of the true economic cost of deer damage needs further research. Deer damage to conservation habitats in England and Wales appears largely restricted to woodland; impact on heathlands, grasslands and wetlands is generally welcomed as helping to arrest invasion of scrub. Within woodlands, while concern is expressed in a small number of cases over losses of sensitive ground flora or suppression of natural regeneration, the major problem is in damage to coppice regrowth on sites where coppice management has been recently reintroduced.
Biological invasions are a threat to biodiversity, society and the economy. There is an urgent need to provide evidence‐based assessments of the risks posed by invasive alien species (IAS) to prioritize action. Risk assessments underpin IAS policies in many ways: informing legislation; providing justification of restrictions in trade or consumer activities; prioritizing surveillance and rapid response. There are benefits to ensuring consistency in content of IAS risk assessments globally, and this can be achieved by providing a framework of minimum standards as a checklist for quality assurance. From a review of existing risk assessment protocols, and with reference to the requirements of the EU Regulation on IAS (1143/2014) and international agreements including the World Trade Organisation, Convention on Biological Diversity and International Plant Protection Convention, coupled with consensus methods, we identified and agreed upon 14 minimum standards (attributes) a risk‐assessment scheme should include. The agreed minimum standards were as follows: (1) basic species description; (2) likelihood of invasion; (3) distribution, spread and impacts; (4) assessment of introduction pathways; (5) assessment of impacts on biodiversity and ecosystems; (6) Assessment of impact on ecosystem services; (7) assessment of socio‐economic impacts; (8) consideration of status (threatened or protected) of species or habitat under threat; (9) assessment of effects of future climate change; (10) completion possible even when there is a lack of information; (11) documents information sources; (12) provides a summary in a consistent and interpretable form; (13) includes uncertainty; (14) includes quality assurance. In deriving these minimum standards, gaps in knowledge required for completing risk assessments and the scope of existing risk assessment protocols were revealed, most notably in relation to assessing benefits, socio‐economic impacts and impacts on ecosystem services but also inclusion of consideration of climate change. Policy implications. We provide a checklist of components that should be within invasive alien species risk assessments and recommendations to develop risk assessments to meet these proposed minimum standards. Although inspired by implementation of the European Union Regulation on invasive alien species, and as such developed specifically within a European context, the derived framework and minimum standards could be applied globally.
Summary1. Coastal grazing marshes comprise an important habitat for wetland biota but are threatened by agricultural intensi®cation and conversion to arable farmland. In Britain, the Environmentally Sensitive Area (ESA) scheme addresses these problems by providing ®nancial incentives to farmers to retain their grazing marshes, and to follow conservation management prescriptions. 2. A modelling approach was used to aid the development of management prescriptions for ground-nesting birds in the North Kent Marshes ESA. This ESA contains the largest area of coastal grazing marsh remaining in England and Wales (c. 6500 ha) and supports nationally important breeding populations of lapwing Vanellus vanellus and redshank Tringa totanus. 3. Counts of ground-nesting birds, and assessments of sward structure, surface topography and wetness, landscape structure and sources of human disturbance were made in 1995 and again in 1996, on 19 land-holdings with a combined area of c. 3000 ha. The land-holdings varied from nature reserves at one extreme to an intensive dairy farm at the other. 4. Models of relationship between the presence or absence of ground-nesting birds and the grazing marsh habitat in each of c. 430 marshes were constructed using a generalized linear mixed modelling (GLMM) method. This is an extension to the conventional logistic regression approach, in which a random term is used to model dierences in the proportion of marshes occupied on dierent land-holdings. 5. The combined species models predicted that the probability of marshes being occupied by at least one ground-nesting species increased concomitantly with the complexity of the grass sward and surface topography but decreased in the presence of hedgerows, roads and power lines. 6. Models were also prepared for each of the 10 most widespread species, including lapwing and redshank. Their composition diered between species. Variables describing the sward were included in models for ®ve species: heterogeneity of sward height tended to be more important than mean sward height. Surface topography and wetness were important for waders and wildfowl but not for other species. Eects of boundaries, proximity to roads and power lines were included in some models and were negative in all cases. 7. Binomial GLMMs are useful for investigating habitat factors that aect the distribution of birds at two nested spatial scales, in this case ®elds (marshes) grouped within farms. Models of the type presented in this paper provide a framework for targeting of conservation management prescriptions for ground-nesting birds at the ®eld scale on the North Kent Marshes ESA and on lowland wet grassland elsewhere in Europe.
The Antarctic is considered to be a pristine environment relative to other regions of the Earth, but it is increasingly vulnerable to invasions by marine, freshwater and terrestrial non‐native species. The Antarctic Peninsula region (APR), which encompasses the Antarctic Peninsula, South Shetland Islands and South Orkney Islands, is by far the most invaded part of the Antarctica continent. The risk of introduction of invasive non‐native species to the APR is likely to increase with predicted increases in the intensity, diversity and distribution of human activities. Parties that are signatories to the Antarctic Treaty have called for regional assessments of non‐native species risk. In response, taxonomic and Antarctic experts undertook a horizon scanning exercise using expert opinion and consensus approaches to identify the species that are likely to present the highest risk to biodiversity and ecosystems within the APR over the next 10 years. One hundred and three species, currently absent in the APR, were identified as relevant for review, with 13 species identified as presenting a high risk of invading the APR. Marine invertebrates dominated the list of highest risk species, with flowering plants and terrestrial invertebrates also represented; however, vertebrate species were thought unlikely to establish in the APR within the 10 year timeframe. We recommend (a) the further development and application of biosecurity measures by all stakeholders active in the APR, including surveillance for species such as those identified during this horizon scanning exercise, and (b) use of this methodology across the other regions of Antarctica. Without the application of appropriate biosecurity measures, rates of introductions and invasions within the APR are likely to increase, resulting in negative consequences for the biodiversity of the whole continent, as introduced species establish and spread further due to climate change and increasing human activity.
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