Morten Tune Strandberg

Nordic Empetrum Dominated Ecosystems: Function and Susceptibility to Environmental Changes

Abstract This paper reviews the knowledge on crowberry (Empetrum nigrum ssp. nigrum and ssp. hermaphroditum) dominated ecosystems in the Nordic region. Empetrum leaves and litter have high phenolic content resulting in slow decomposition, and with the formation of an organic top soil, nutrients are kept in an organic nutrient bank in the soil mainly available for plants with ericoid mycorrhiza. Empetrum nigrum ssp. hermaphroditum is a strong nutrient competitor and outcompetes most plants in late successional stages. This is due to chemical interference (allelopathy) and resource competition. Crowberry as an organism is resistant to atmospheric pollution and may even increase in vigor by high atmospheric N deposition in nemoral coastal heaths, but is very sensitive to mechanical disturbances and fire. However, there are indications that the closed nutrient cycle established when Empetrum is dominant may be disturbed after airborne inputs of inorganic N.

Pervasive early 21st‐century vegetation changes across Danish semi‐natural ecosystems: more losers than winners and a shift towards competitive, tall‐growing species

Summary Semi-natural open habitats in north-western Europe are highly prioritized for conservation, and optimization of management planning is essential for continued protection of their diversity. We evaluate whether current management practices, which consist mainly of summer grazing by livestock, are sufficient to maintain plant species composition in a stable state across semi-natural areas in Denmark, or if shifts in functional composition are taking place. Further, we investigate important drivers of any ongoing changes through trait differences between winner and loser species. Using a data set of 6513 annually inventoried (2004–2010) vegetation plots from 202 semi-natural NATURA 2000 protected areas, we assessed changes in cover of all plant species and, using boosted regression trees, whether winners and losers differ in regard to autecological characteristics and traits. There were consistent changes in cover for 123 out of 603 species across the 6-year study period, with more species losing than winning (78 vs. 45). Winner and loser species were strongly differentiated by competition-related traits, but traits related to soil nutrients and soil moisture also had some importance. Generally, our results indicate a trend towards taller and more competitive species. Synthesis and applications. Despite conservation actions in order to maintain a so-called favourable conservation status, vegetation in NATURA 2000 protected areas is still undergoing compositional changes. Overall, autecological characteristics and trait differences between winners and losers match expectations given the contemporary anthropogenic pressures, especially reduced livestock grazing. Atmospheric nitrogen deposition and increased soil moisture due to reduced drainage might also be involved in observed changes. Current management (i.e. summer grazing by livestock) is insufficient to preserve the diversity of less-competitive, low-statured and stress-tolerant herbaceous species, potentially leading to species losses. Such patterns can thus be expected across semi-natural ecosystems in north-western Europe and other places where traditional land use (i.e. previous widespread extensive livestock grazing) have been replaced with various degrees of conservation management. A greater focus on returning large grazing herbivores to conservation areas is recommended for the protection of plant species diversity and to counteract ongoing changes.

Monitoring and surveillance of genetically modified higher plants

1 Introduction.- 1.1 How to use this book.- 1.2 Biotechnology and new GM crops placed on the market.- 1.3 Risk assessment, monitoring and the EU directives.- 2 Environmental concerns and concepts.- 2.1 The risk of GMHP invasion.- 2.2 Ecological effects of GMHP.- 2.3 Concepts and definitions.- 2.4 List of relevant links for information on monitoring of GMHP.- 3 Monitoring and surveillance of GMHP dispersal and effects.- 3.1 Objectives for monitoring programs.- 3.2 Scheme for the process of monitoring GMHP.- 3.3 Approaches to monitoring.- 3.3.1 Quality of monitoring programs.- 3.3.2 GMHP monitoring experience.- 3.3.3 Monitoring methods for other environmental purposes.- 3.4 Factors that may make a community invasible.- 3.5 Suggestions for a tripartite monitoring program.- 3.5.1 Dispersal subprogram.- 3.5.2 Effects subprogram.- 3.5.3 Surveillance subprogram.- 3.5.4 Problems related to effect monitoring.- 3.6 Data analysis and evaluation of results.- 3.7 Extent of monitoring.- 3.8 Reassessment of established monitoring procedures.- 4 Perspectives of habitat selection.- 4.1 Background for habitat selection in Denmark and EU.- 4.2 Important factors for selection of exposed areas.- 4.3 Background for habitat selection in relation to GMHP-monitoring.- 4.3.1 Case-by-case selection.- 4.4 Which habitats should be monitored?.- 4.4.1 Why select disturbed and grass dominated habitats?.- 4.4.2 Danish disturbed habitats dominated by grasses.- 4.5 General changes affecting plants and other organisms.- 4.6 Baseline definition.- 5 Agricultural use and effects of GMHP.- 5.1 Detection of adverse effects in cultivated fields.- 5.2 Effects and monitoring of GM crops used in large-scale farming.- 6 Dispersal of GMHP and transgenes.- 6.1 Detection of GMHP dispersal and invasion.- 6.2 Detection of hybridisation and transgene dispersal.- 7 Effect identification and detection.- 7.1 Effect types, identification and assessment.- 7.2 Assessment of effects on vegetation, ecosystem structure and function.- 7.3 Detection of effects on soil organisms.- 7.3.1 Microbiological activity.- 7.3.2 Soil animals.- 7.4 Detection of effects on aboveground organisms.- 7.4.1 Detection of effects on plant species.- 7.4.2 Detection of effects on insects.- 7.4.3 Detection of effects on birds and mammals.- 7.5 Sampling designs and data analysis methods.- 8 Data analysis and evaluation.- 8.1 Statistical methods and tools.- 8.2 Use of modelling to assist monitoring.- 8.3 Evaluation, information management and policy making.- 9 Conclusions and recommendations.- 10 References.- 11 Subject index.

The effect of grazing on biodiversity in coastal dune heathlands

The effect of sheep grazing on species richness, higher order diversity measures, inequality, species composition, functional diversity and allometric relationships at a coastal dune heathland site was investigated. After a prescribed fire in 2002, the site was divided into two parts, where one of the parts was unmanaged and the other part was fenced and grazed by sheep. Sheep grazing had a positive effect on species richness as well as a significant positive effect on the functional diversity at the coastal dune heathland site. Generally, the cover of dwarf shrubs was negatively affected by grazing, whereas the cover of sedges and grasses was positively affected by grazing. There is a need for comparative investigations of the effect of different management methods not only on floristic biodiversity, but on all relevant kinds of biodiversity as well as on soil structure, soil chemistry and habitat micro- and macrostructure. Consequently, we advocate the initiation of an international systematic investigation of the effect of different management methods.

Relationship Between Atmospheric Ammonia Concentration and Nitrogen Content in Terricolous Lichen (Cladonia portentosa)

From April 2006 to April 2007, the geographical and seasonal variation in nitrogen content in terricolous lichen (Cladonia portentosa) and atmospheric ammonia concentrations were measured at five heathland sites. The seasonal variation in the nitrogen content of the lichen was small, even though there was a large seasonal variation in the air concentration of ammonia. A sizable local variation in the nitrogen content of the lichen was found even at the scale of a few kilometres. The nitrogen content in the lichen showed a high correlation to the yearly mean value of the measured ammonia concentration in air at the different locations. This investigation is part of a larger attempt to incorporate effects of nitrogen in the conservation status of terrestrial habitat types.

The effect of nitrogen deposition on the vegetation of wet heathlands

The statistical modelling of joint species abundance is currently receiving increasing attention in the ecological literature because it complements earlier descriptive accounts of the effect of disturbance on community change with quantitative measures of spatial covariation among species at different spatial scales. Using a hierarchical Bayesian approach, we fitted both temporal and spatial plant cover data to a joint distribution model of plant abundance of the dominant plants in wet heathlands (Erica tetralix, Calluna vulgaris and Molinia caerulea) undergoing nitrogen deposition over several decades. The spatial analysis was based on pin-point cover data from 114 Danish sites with a total of 1509 randomly placed plots along a nitrogen deposition gradient. The temporal analysis was based on pin-point cover data from 22 sites with a total of 986 observations from plots that had been resampled at least three times since 2007. The spatial variation was partially explained by nitrogen deposition, as the cover of Erica decreased significantly with nitrogen deposition, whereas the cover of both Calluna and Molinia increased (albeit non-significantly) with nitrogen deposition. There was a strong and significant positive spatial covariation between Erica and Calluna. Oppositely, there was a strong and significant negative spatial covariation between Calluna and Molinia. The spatial covariation between Erica and Molinia was not significantly different from zero. There were no significant changes in the cover of any of the three species since 2007. However, by including data from 2004, the previously reported result of a significant decreasing cover of Erica was confirmed, and the cover of Calluna increased significantly. We conclude that the statistical modelling of joint species abundance is a potentially powerful tool to understand the effect of the alteration of nitrogen dynamics on community composition. This is essential to design management practices aligned with the predicted effects of varying levels of nitrogen deposition on community structure. The study also demonstrated the insight gained on the community dynamics by the use of hierarchical Bayesian models.

Identifying potential gaps in pesticide risk assessment: Terrestrial life stages of freshwater insects

1.Insecticides are important drivers of biodiversity loss and ecological impairment in freshwater ecosystems. Freshwater insects may be exposed to insecticides via water during larval/nymph stages and via air, habitats, and food during adult stages in the terrestrial environment. 2.The aquatic risk assessment (RA) of pesticides does not consider terrestrial life stages, and a literature review revealed that pesticide ecotoxicity data for adult freshwater insects are very scarce and outdated. Consequently, it is not possible to assess how adult freshwater insects may be protected through RA programs for terrestrial non-target organisms. 3.We give guidance to generating and using of such ecotoxicity data focusing on species selection, test design, and type of ecotoxicity information. 4.Policy implications. This commentary considers how terrestrial stages of aquatic insects are protected by pesticide risk assessment (RA) and highlights the necessity of performing holistic RA, focusing on organisms and populations as supplement to current subdivisions in element-based compartments (e.g. aquatic and terrestrial ecosystems). This article is protected by copyright. All rights reserved.

Data analysis and evaluation

The choice of pertinent methods for analysis of the different types of data from monitoring is crucial for an evaluation of the ecological effects. The statistical methods ideally need to be an integrated part of the monitoring plan already at the planning stage. This means that practical decisions on survey procedures, monitoring design, number of replicates, survey intervals, etc. all depend on the type of statistical tests which will be used to analyse a particular question. An important tool to help in achieving this goal is the use of statistical power analysis before survey start.

Agricultural use and effects of GMHP

This chapter presents and discusses the specific problems and types of effects from GM crops that may occur in the cultivated fields and surroundings, and suggestions are made for surveillance and monitoring. General targets for monitoring of two different types of GM crops are presented (Section 5.1), and risk-aspects of large-scale farming are discussed in particular in relation to organic farming (Section 5.2).

Dispersal of GMHP and transgenes

This chapter covers background, methods and procedures for detection of dispersal and invasion of GM plants and gene flow and hybridisation involving the transgene. The GM crop plant can, depending on the species, disperse through pollination of other individuals, through seed dispersal, through survival in the soil seed bank or through vegetative fragmentation (Section 6.1). The inserted transgene can also spread to related species through cross-pollination and hybridisation (Section 6.2). Experience from monitoring trials and information on current regulation is provided, and different ways of detection and their limitations are discussed below. Indirect effects of GM crop use, such as weeds which become resistant to herbicides, and the consequences to management are also discussed.