Simulation of control drives in a tower crane

The design of a control system for a tower crane is investigated. Underlying the controller design is the theory of optimal linear control. Computer models of a crane and the control systems for the crane drives are developed. Simulation data reveals that the motion of the load can be effectively controlled so that it should follow a predetermined trajectory

Territory choice during the breeding tenure of male sedge warblers

A territorial male can shift the location of its territory from year to year in order to increase its quality. The male can base its decision on environmental cues or else on its breeding experiences (when territory shift is caused by breeding failure in previous seasons). We tested these possible mechanisms of territory choice in the sedge warbler (Acrocephalus schoenobaenus), a territorial migrating passerine that occupies wetlands. This species bases its territory choices on an environmental cue: tall wetland vegetation cover. We found that the magnitude of territory quality improvement between seasons (measured as the area of tall wetland vegetation) increased throughout the early stages of a male's breeding career as a result of territory shifts dependent on the earliness of arrival. The distance the territory was shifted between seasons depended negatively on the previous year's territory quality and, less clearly, on the previous year's mating success. On the other hand, previous mating or nesting success had no influence on territory quality improvement between seasons as measured in terms of vegetation. The results imply that tall wetland vegetation is a long-term, effective environmental cue and that a preference for territories in which this type of landcover prevails has evolved into a rigid behavioral mechanism, supplemented by short-term individual experiences of breeding failure

Do local enemies attack alien and native Impatiens alike?

The enemy release hypothesis (ERH) attributes the invasive behavior of some alien species to decreased pressure from natural enemies, as they have been left behind in the hosts’ native range. The majority of research supports this idea, but some studies confirm it only partially or even contradict it. Here, we present the results of ERH tests of three Impatiens species studied in southern Poland in 2010–2011. Two of them are alien and invasive in Europe (Impatiens glandulifera, I. parviflora) and one is native (I. noli-tangere). We compared the three species in terms of the percentage of all leaves showing symptoms of disease and/or damage, and also the number of pests recorded on the monitored plants. In 1071 individual plant controls, we assessed 17 180 leaves, 7552 of which showed symptoms of disease/damage, and we recorded 5721 invertebrates, 5220 of them were pests. Rusts and spots were the predominant symptoms and Aphidoidea were the dominant group of pests. Comparisons of the two alien and one native Impatiens did not confirm the ERH in 90% of the performed tests. Most of the differences between the species were not significant, and most of the significant ones contradicted the ERH. The only results confirming the ERH were found in comparisons between I. parviflora and I. noli-tangere. The tests between two alien species showed that I. parviflora was under higher pest pressure, while I. glandulifera had more disease and damage symptoms, thus, plant–enemy relations differed between the two balsams. In summary, the presented results add evidence that the success of some alien species may depend on factors related to biotic and/or abiotic conditions in ways that are not explained by the enemy release hypothesis

Flowers of Impatiens glandulifera as hubs for both pollinators and pathogens

Flower infestation by pathogens may influence pollination effectiveness. At the same time, by sharing infested flowers, pollinators increase transmission of pathogens. In the presented study we identified fungi that colonised flowers of the invasive alien Himalayan balsam Impatiens glandulifera, one of the most nectar rewarding plants in Europe, as well as its pollinators. We determined factors (e.g., plant size, length of flower lower sepal and the width of its entry, air temperature and sun illuminance) that affect pathogen species presence and pollinators numbers. The study was conducted in three regions in Poland differing in time from the I. glandulifera invasion onset. It allowed embedding our results in the context of the evolution of increased competitive ability (EICA) hypothesis. With reference to this hypothesis we tested whether I. glandulifera from the two younger populations are more frequently pollinated than individuals from the old one, which may be a result of the higher infection prevalence in the flowers of individuals from the latter population. Harmful primary pathogens of I. glandulifera (e.g., Botrytis cinerea and Fusarium graminearum) were identified from its flowers. Although the knowledge of the impact of the recorded pathogen species on the pollinators that transmit them is still limited, these pathogens are known to cause devastating diseases of native plant species and to incur significant economic losses in crops. Therefore, the facilitation of their transmission by I. glandulifera in the invaded communities may pose a serious threat both to native biodiversity and nearby crop production. We did not find support for the EICA hypothesis that flower release from pathogens may increase the pollinator’s activity. Bombus hortorum was the most frequent visitor in the youngest surveyed population, while B. pascuorum was most frequent in the two others. So far the dominance of B. hortorum as a pollinator of I. glandulifera has not been recorded. A possible explanation is that flowers in the youngest population, with significantly wider entries than in the two older ones, were more accessible for this large bumblebee. We suggest that the shifts in flower dimensions may result from the evolutionary processes and/or phenotypic plasticity; however, this suggestion needs to be confirmed in further studies. At the same time, it can be expected that exceptionally frequent visits of B. hortorum in flowers of I. glandulifera in the youngest population may contribute to increasing transmission rate of pathogen species to the new native host plants that are particularly associated with this pollinator

Invasive alien plants in Poland - the state of research and the use of the results in practice

The participation of species of alien origin in the flora of individual regions of the world is increasing. A large proportion of these species pose a threat to biodiversity. Issues of the dynamics of changes in the flora and the scale and pace of the processes, with particular emphasis on the biology, ecology, chorology, and genetic variability of the populations of plants of alien origin, including those alien species which are invasive, have been the subject of many years of research in this field in Poland. The present study is an overview of the state of research on invasive plant species in Poland, including the main results of the basic and applied research which have provided the basis for (i) the preparation of a list of invasive plant species for Poland; (ii) assessing the degree of invasiveness of the species analysed, in accordance with the adoption of criteria and the development of methodological solutions. In this work, a new version of the list of invasive plant species has been prepared on the basis of earlier studies, combining theoretical and practical aspects of definition, and it is compared with the list of invasive alien plant species considered to constitute a threat to the EU and Poland as a member country. The categorization (risk assessment) of invasive alien species along with the identification of the most endangered types of natural habitats is often used in practice in the management of invasive plants in Poland. The results of our research have fed into the formulation of legal regulations at the global and regional levels

ARES(2014)2425342 - 22/07/2014. Organisation and running of a scientific workshop to complete selected invasive alien species (IAS) risk assessments

The introduction and spread of invasive alien species (IAS) constitutes one of the most important drivers of global change in biodiversity and ecosystem services. Robust risk assessment methods are required for IAS to provide the foundation upon which to prioritise appropriate action. In a previous study (Roy, Schonrogge et al. 2014) minimum standards were developed to provide an assessment framework for risk assessments and ultimately for underpinning the development of a proposed list of “IAS of EU concern”, in accordance to the provisions of the Regulation (EU) No 1143/2014 of the European Parliament and of the Council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species. In practice, of the protocols assessed in detail, only four (GB NNRA, EPPO DSS, Harmonia+ and ENSARS) were sufficiently compliant with the minimum standards to be considered and of these only the GB NNRA and EPPO DSS have published IAS risk assessments. As a result, using the information from such “substantially compliant” protocols, a draft list of approximately 50 species was compiled. It is important to note that this list of species is based on availability of robust risk assessments already completed through methods which are almost compliant with the minimum standards, and it does not constitute the list of “IAS of EU concern”. In view of the application of the forthcoming EU Regulation on IAS (and building-on ENV.B.2/ETU/2013/0026) the Commission hosted a 2-day scientific workshop to examine the selected risk assessments and pool the existing knowledge existing in the EU to complete the missing information, on the basis of robust scientific evidence, in order to make them fully compliant with the minimum standards, wherever possible. The workshop was led by Helen Roy (CEH) and Riccardo Scalera (ISSG). An additional 16 experts from fifteen member states were selected based on their expertise in invasion biology and represented a breadth of expertise from a variety of perspectives including taxonomic (all taxa), environmental (freshwater, marine and terrestrial), impacts (environmental, socio-economic and health) and disciplines (ecologists, conservation practitioners, scientists, policy-makers, risk assessors). In view of the gaps across risk assessments for ecosystem services and climate change two experts were invited to guide the development of approaches for these specific themes. In total the risk assessments for 56 species were considered. The GB NNRA and EPPO DSS have published IAS risk assessments which, when considering species that score medium to high impact, together cover 51 species (noting that Fallopia japonica and F. sachalinensis are separate species). Two further risk assessments were suggested for consideration by the GB Non-Native Species Secretariat which follow the GB NNRA protocol: coati (Nasua nasua) and skunk (Mephitis mephitis), although scored as low impact. Finally an additional three species have been considered through new European–wide risk assessments, with the reported outcome of high impact, for this project which again follow the GB NNRA protocol: Pallas squirrel (Callosciurus erythraeus), grey squirrel (Sciurus carolinensis) and coypu (Myocastor coypus). The main gaps across all risk assessments were in relation to climate change and ecosystem services but additional information was also required on benefits as mentioned with minimum standard “Description (Taxonomy, invasion history, distribution range (native and introduced), geographic scope, socio-economic benefits)” and in some cases information to support the minimum standard “Includes status (threatened or protected) of species or habitat under threat“ was missing. It was agreed that systematic consideration of a list of questions in relation to the minimum standards on ecosystem services and climate change would be useful guidance for experts. An outline of the approaches agreed through the workshop for the minimum standards “Includes possible effects of climate change in the foreseeable future“ and “Can broadly assess environmental impact with respect to ecosystem services” were developed as guidance for documenting information in relation to climate change and ecosystem services. Each species was considered separately with the experts providing an overview of the information available for addressing the identified gaps. After all species had been considered the workshop participants (excluding the EC, Helen Roy and Riccardo Scalera) adopted a consensus approach to confirm whether or not the risk assessment was compliant with the minimum standards and whether the overall score of the risk assessment remained applicable. No changes were made to the scores but any recommendations were noted. There were very few recommendations for change. The outcome for each risk assessment was agreed and summarised as “compliant” or “not compliant” with the minimum standards. Of the risk assessments for the 56 species considered through this project, 53 were agreed to be fully compliant with the minimum standards. However, Pacific oyster, Crassostrea gigas, although compliant with the minimum standards should be excluded as it is not within the scope of the regulation (see art 2.e) because it is listed in annex IV of Council Regulation (EC) No 708/2007 of 11 June 2007 concerning use of alien and locally absent species in aquaculture. Four of the risk assessments were not considered to be compliant because of major information gaps: Elodea canadensis (Canadian pondweed), Heracleum mantegazzianum (giant hogweed), M. mephitis (skunk), N. nasua (coati)

A scenario‐guided strategy for the future management of biological invasions

Future dynamics of biological invasions are highly uncertain because they depend on multiple social–ecological drivers. We used a scenario-based approach to explore potential management options for invasive species in Europe. During two workshops involving a multidisciplinary team of experts, we developed a management strategy arranged into 19 goals relating to policy, research, public awareness, and biosecurity. We conceived solutions for achieving these goals under different plausible future scenarios, and identified four interrelated recommendations around which any long-term strategy for managing invasive species can be structured: (1) a European biosecurity regime, (2) a dedicated communication strategy, (3) data standardization and management tools, and (4) a monitoring and assessment system. Finally, we assessed the feasibility of the management strategy and found substantial differences among scenarios. Collectively, our results indicate that it is time for a new strategy for managing biological invasions in Europe, one that is based on a more integrative approach across socioeconomic sectors and countries

European scenarios for future biological invasions

1. Invasive alien species are one of the major threats to global biodiversity, ecosystem integrity, nature's contributions to people and human health. While scenarios about potential future developments have been available for other global change drivers for quite some time, we largely lack an understanding of how biological invasions might unfold in the future across spatial scales. 2. Based on previous work on global invasion scenarios, we developed a workflow to downscale global scenarios to a regional and policy-relevant context. We applied this workflow at the European scale to create four European scenarios of biological invasions until 2050 that consider different environmental, socio-economic and socio-cultural trajectories, namely the European Alien Species Narratives (Eur-ASNs). 3. We compared the Eur-ASNs with their previously published global counterparts (Global-ASNs), assessing changes in 26 scenario variables. This assessment showed a high consistency between global and European scenarios in the logic and assumptions of the scenario variables. However, several discrepancies in scenario variable trends were detected that could be attributed to scale differences. This suggests that the workflow is able to capture scale-dependent differences across scenarios. 4. We also compared the Global- and Eur-ASNs with the widely used Global and European Shared Socioeconomic Pathways (SSPs), a set of scenarios developed in the context of climate change to capture different future socio-economic trends. Our comparison showed considerable divergences in the scenario space occupied by the different scenarios, with overall larger differences between the ASNs and SSPs than across scales (global vs. European) within the scenario initiatives. 5. Given the differences between the ASNs and SSPs, it seems that the SSPs do not adequately capture the scenario space relevant to understanding the complex future of biological invasions. This underlines the importance of developing independent but complementary scenarios focussed on biological invasions. The downscaling workflow we implemented and presented here provides a tool to develop such scenarios across different regions and contexts. This is a major step towards an improved understanding of all major drivers of global change, including biological invasions