• Energy Research

AbstractThe composition of weed floras in Central European fields has shifted creating a novel management issue: new weeds, that is, species that are currently spreading and increasing in impact. In their role as primary decision makers on the ground, farmers' perception of these new weeds plays a pivotal role in collecting information on their occurrence and control. We conducted an online survey to determine if Austrian farmers recognized 15 selected new weed taxa (12 species and 3 genera) from their farm. The 181 surveyed farmers also estimated the required management effort for these species and elicited their current management practices. Additional questions were posed to understand farmers' general perception of changes in the weed flora. We used a generalized linear mixed model to estimate differences in management effort and identify new weeds that merit monitoring and management programs. Two weed genera (Fallopia spp. and Panicum spp.) showed significantly higher than average management effort. The most commonly used management measures were manual removal, herbicide use and crop rotation. A majority of farmers reported changes in the weed flora; over two thirds reported new species and over one third reported new weeds that were difficult to control. In summary, our results suggest that respondents were aware of the challenges posed by new weeds but required more information on management and prevention strategies.

Summary This account presents information on all aspects of the biology of Ambrosia artemisiifolia L. (Common ragweed) that are relevant to understanding its ecology. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, and history, conservation, impacts and management. Ambrosia artemisiifolia is a monoecious, wind‐pollinated, annual herb native to North America whose height varies from 10 cm to 2.5 m, according to environmental conditions. It has erect, branched stems and pinnately lobed leaves. Spike‐like racemes of male capitula composed of staminate (male) florets terminate the stems, while cyme‐like clusters of pistillate (female) florets are arranged in groups in the axils of main and lateral stem leaves. Seeds require prolonged chilling to break dormancy. Following seedling emergence in spring, the rate of vegetative growth depends on temperature, but development occurs over a wide thermal range. In temperate European climates, male and female flowers are produced from summer to early autumn (July to October). Ambrosia artemisiifolia is sensitive to freezing. Late spring frosts kill seedlings and the first autumn frosts terminate the growing season. It has a preference for dry soils of intermediate to rich nutrient level. Ambrosia artemisiifolia was introduced into Europe with seed imports from North America in the 19th century. Since World War II, it has become widespread in temperate regions of Europe and is now abundant in open, disturbed habitats as a ruderal and agricultural weed. Recently, the North American ragweed leaf beetle (Ophraella communa) has been detected in southern Switzerland and northern Italy. This species appears to have the capacity to substantially reduce growth and seed production of A. artemisiifolia. In heavily infested regions of Europe, A. artemisiifolia causes substantial crop‐yield losses and its copious, highly allergenic pollen creates considerable public health problems. There is a consensus among models that climate change will allow its northward and uphill spread in Europe.

AbstractAimsArable habitats (i.e. fields, orchards, vineyards, and their fallows) were created by humans and have been essential elements in Central European landscapes for several millennia. In recent decades, these habitats have been drastically altered by changes in land use as well as agricultural practices and, more recently, by climate change. These changes have precipitated substantial changes in vegetation and their spatial and temporal trajectories have not yet been exhaustively studied. Here, we present the AgriWeedClim database — a new resource of vegetation plot (relevé) data of arable habitats in Central Europe.LocationGermany, Czech Republic, Slovakia, Switzerland, Liechtenstein, Austria, Hungary, Northern Italy, Slovenia, Croatia.MethodsVegetation plot data were obtained from large repositories (e.g. European Vegetation Archive), specialized regional databases, colleagues and the literature. Data were then checked for completeness and standardized (e.g. taxonomy, nomenclature, crop types). Species were assigned native, archaeophyte (i.e. alien species introduced before c. 1492 CE) or neophyte (i.e. alien species introduced after c. 1492 CE) status.ResultsThe AgriWeedClim database version 1.0 contains georeferenced data from 32,889 vegetation plots sampled from 1916 to 2019.ConclusionsWe provide an overview of this new resource and present example analyses to show its content and possible applications. We outline potential research questions including analysis of patterns and causes of vegetation changes in arable habitats from the early 20th century to the present.

No saturation in the introduction, acceleration of spread and the increasing impacts of alien species are a characteristic feature of the Anthropocene. Concomitantly, alien species affecting human health are supposed to increase, mainly due to increasing global trade and climate change. In this study, we assess challenges and solutions posed by such species to the public health sector in Austria over the next few decades. We did so using an online questionnaire circulated to 131 experts and stakeholders working on human health and biological invasions, supplemented by in-depth interviews with eleven selected experts. Results from the online survey and in-depth interviews largely support and complement each other. Experts and stakeholders suggest that (i) the allergenic Ambrosia artemisiifolia (common ragweed), the photodermatoxic Heracleum mantegazzianum (giant hogweed), and vectors of diseases such as Aedes albopictus (Asian tiger mosquito) are considered the alien species posing the most severe challenges; (ii) challenges are expected to increase in the next few decades and awareness in the public health sector is not sufficient; (iii) effective and efficient solutions are mainly related to prevention. Specific solutions include pathway management of introduction and spread by monitoring and controlling established populations of ragweed, hogweed and mosquitos.