Thomas Persson

Soil water and temperature patterns in an arid desert dune sand

Abstract Under arid natural conditions, soil water content governs and limits the number and size of perennial plant species. Thus, plant-available soil water is the main constraint for sustainable control of desert encroachment. To evaluate possibilities for re-vegetation of bare sand surfaces, soil water and temperature patterns for typical sand dunes in a desert climate were investigated. Bare and vegetated soil transects were selected for observation of soil water content and temperature. The investigated soil transects covered crest-to-crest spacings (about 60 m horizontally and 15 m vertically) in a shifting sand dune area. Observations were made at Shapotou field research station bordering the Tengger Desert in Northwestern China. The paper presents two-dimensional properties of soil water content (0.1–3.0 m depth) and temperature (0–1.0 m depth) before and after rainfall. Rainfall (15–22 mm) affected soil water distribution down to 1.5–2.0 m and temperature distribution down to 1.0 m. Soil water appeared to be transported through the apparently highly pervious and homogeneous sand along the dune slopes. High water contents and, thus, infiltration occurred mainly at the non-sloping parts, i.e. the dune crests and bottoms. Rainfall changed the temperature patterns from a mainly horizontally layered appearance before the rainfall to increasingly vertically shaped patterns.

Pollen-based quantitative reconstructions of Holocene regional vegetation cover (plant-functional types and land-cover types) in Europe suitable for climate modelling

We present quantitative reconstructions of regional vegetation cover in north-western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1° × 1° spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant-functional types and three land-cover types [evergreen trees, summer-green (deciduous) trees, and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen, and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However, the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k, 0.5k, and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe, in particular Britain and Ireland. Furthermore, the relationship between summer-green and evergreen trees, and between individual tree taxa, differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance, when Pinus is dominant over Picea as pollen percentages, Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover-climate interactions, biodiversity and human resources.

Input and output legitimacy: synergy or trade-off? Empirical evidence from an EU survey

Since the breakdown of the ‘permissive consensus’ in the early 1990s we have witnessed an input turn in the debate on EU legitimacy. Many scholars have been arguing for enhancing the input legitimacy of the EU through promoting stakeholder participation and deliberation on important European issues. Yet, others warn that this strategy might not help in increasing overall legitimacy of the EU, since increased input legitimacy could be thought to undermine its output legitimacy by making decision-making less efficient. This article assesses, empirically, the relationship between input and output legitimacy within the context of the EU chemicals policy overhaul. Contrary to what some scholars suggest, we find evidence from a survey that measures aimed at increasing the input legitimacy of the EU also hold the promise of increasing its output legitimacy.

Democratizing European Chemicals Policy: Do Consultations Favour Civil Society Participation?

Abstract As part of the strategy for better governance, the European Commission has taken steps towards improved consultation and dialogue on European Union (EU) policy with interested parties. Opening up the policy process and getting interest groups involved are considered important for the democratic legitimacy of EU policy making. This article examines the public Internet consultation on the Commission proposal for a new European chemicals policy, the so-called REACH system. Being one of the most consulted issues in EU history, the chemicals policy review is considered as a critical test for the participatory mechanisms provided by the European Communities. By analysing more than 6000 contributions to the consultation, it is demonstrated that it invited broad participation, although industry was considerably better represented than NGOs and other civil society associations. Moreover, an overwhelming majority of participants were national actors from the largest member states rather than transnational actors. It is concluded that online consultations can invite broad participation in EU policy shaping but it is unlikely to bring about equal participation from different group of actors. Therefore it raises concern when measured against standards of democratic governance.

Influence of landscape structure on mosquitoes (Diptera: Culicidae) and dytiscids (Coleoptera: Dytiscidae) at five spatial scales in Swedish wetlands

Patterns of species diversity and community structure depend on scales larger than just a single habitat and might be influenced by the surrounding landscape. We studied the response of two insect families, mosquitoes (Diptera: Culicidae) and dytiscids (Coleoptera: Dytiscidae), to landscape variables at five spatial scales. We studied adult mosquito and dytiscid abundance, diversity, and species assemblages in relation to water permanence (area of permanent water bodies versus temporary wetlands) and forest cover (area covered by forest versus open land) within nested circles of 100 to 3000 m around trap sites in four wetlands in southern Sweden and in five wetlands in central Sweden. We found that mosquito abundance was greatest in areas with plentiful forest cover and a high proportion of temporary water, while most dytiscids favored open areas with a high proportion of permanent wetlands. However, diversity of both mosquitoes and dytiscids was positively correlated with high permanence and little forest cover. Mosquito species assemblages were mainly influenced by forest cover at a large spatial scale, whereas permanence was more important at local scales. Dytiscid species assemblages were mainly influenced by water permanence, especially at intermediate spatial scales. These results can be explained by the flight capability and dispersal behavior of mosquito and dytiscid species. The observed landscape associations of mosquitoes and dytiscids could be useful when creating new wetlands. Mosquito colonization could be reduced by creating permanent wetlands in an open landscape, which would favor colonization by dytiscids, a potential predator of mosquito larvae, while also supporting the diversity of both taxa.

Comparison of two concentration methods for pollen in minerogenic sediments

Abstract This study concerns a comparison of the conventional HF method and a method using ZnCl2 as a heavy liquid, combined with HF, for the concentration of pollen in minerogenic sediments. The investigation clearly shows that the ZnCl2 method is as accurate as the HF method and is superior as regards both the concentration and the preservation of pollen grains.

The ankle strategy for postural control—a comparison between a model-based and a marker-based method

When analysing postural control statistical characteristics of the centre of pressure or the ground reaction force are often used. A complement would be to analyse movement strategies as well. The purpose of this study was to determine to what extent the ankle strategy is used to maintain the balance in standing. One important question is if it is sufficient to use only force plate data in this determination, or if markers have to be used. To answer this question we studied two different methods--a marker-based method and a model-based method. The latter needs force plate data only as input to an inverted pendulum model. Different measures were calculated and used to draw conclusions of to what extent the ankle strategy was used. Experiments demonstrated that the data from the two methods provided the same general conclusions, although there were some differences in the estimated measures. By using the model-based method instead of tracking markers we can increase the clinical effectiveness considerably, get a lesser amount of data, and still get results comparable to the marker-based method.

Can overconfidence be used as an indicator of reconstructive rather than retrieval processes

In a recent paper Wagenaar (1988) suggested that overconfidence can be used as an indicator of reconstructive processes which allow responses based on inference to be distinguished from responses based on retrieval. The ecological models (Björkman, in press; Gigerenzer, Hoffrage, & Kleinbölting, 1991; Juslin, 1993a, 1993b, 1994) provide a more positive view of the calibration of reconstructive responses. In this paper we compare these two views and argue that overconfidence cannot be considered a reliable indicator of reconstructive processes since people may be well calibrated for tasks that require inference, provided that tasks are selected in offunbiased manner. Instead, we discuss two different models: the response-independence model which is appropriate to retrieval, and the response-dependence model which applies to inference. These two models predict different distributions of solution probabilities and they therefore provide a criterion by which we can distinguish between direct retrieval and reconstruction. In two empirical studies modelled after Experiment 1 in Wagenaars (1988) paper it is shown that calibration can be very similar and quite reasonable both for tasks that are dominated by inference and tasks that are dominated by retrieval processes. In Experiment 2 we show that the two conditions nevertheless differ in regard to the distributions of solution probabilities in the manner predicted by the two response models presented in the paper. It is proposed that the issue of which is the most appropriate interpretation of solution probabilities is neglected, and that the criterion should be of interest also to applications outside the domain of calibration research.

Biotic responce to climatic changes during the time span 13 000 - 10 000 BP. - A case study from SW Sweden.

Palaeoecological studies based on analysis of pollen, plant macro-fossils and insect remains at a stratigraphic reference site, covering the time span 13,000–10,000 yrs B.P., in SW Sweden (Hakulls Mosse, province of Skane) are interpreted against the two dominant palaeoclimatic models: the palaeobotanical model (Iversen) and the palaeoentomological model (Coope). An important time lag is found in the vegetation response to climatic improvement after deglaciation, which means that the biotic changes are best explained against the palaeoentomological model. This implies optimal summer temperatures 13,000–12,500 followed by a gradual deterioration until 11,000 when a sudden drop of temperature leads to a minimum between 11,000 and 10,500. A distinct rise of summer temperature around 10,500 is confirmed although the time lag in the vegetation response is ab. 300 years.

Party Size and Portfolio Payoffs: The Proportional Allocation of Ministerial Posts in Coalition Governments

Over 30 years ago, Eric Browne and Mark Franklin demonstrated that parties in a coalition tend to receive portfolio payoffs in almost perfect proportionality to their seat share. Even though this result has been confirmed in several studies, few researchers have asked what the underlying mechanism is that explains why parties receive a proportional payoff. The aim of this paper is to investigate the causal mechanism linking party size and portfolio payoffs. To fulfil this aim, a small-n analysis is performed. By analysing the predictions from a statistical analysis of all post-war coalition governments in 14 Western European countries, two predicted cases are selected, the coalitions that formed after the 1976 Swedish election and the 1994 German election. In these case studies two hypotheses are evaluated: that the proportional distribution of ministerial posts is the result of a social norm, and that parties obtain payoffs according to their bargaining strength. The results give no support to the social norm hypothesis. Instead, it is suggested that proportionality serves as a bargaining convention for the actors involved, thus rendering proportional payoffs more likely.