Per Milberg
Linköping University, IFM Biology, Faculty Member
- Plant ecologist with a particular interest in applied ecology, especially conservation of species and habitats. Also interested in weeds and seeds, and in general natural history.edit
Questions Can signs of 19th century grassland management, which can be observed in the flora immediately (2–4 yrs) after clear-cutting in boreonemoral Sweden, still remain 4 yrs later? Do the effects from the time since clear-cutting... more
Questions Can signs of 19th century grassland management, which can be observed in the flora immediately (2–4 yrs) after clear-cutting in boreonemoral Sweden, still remain 4 yrs later? Do the effects from the time since clear-cutting differ between forest and grassland plant species? Location Province of Ostergotland, southern Sweden. Methods Twelve contemporary clear-cut areas that were once meadows and 12 that were once forests were selected using land-use maps from the 1870s. Grasses and herbaceous plants were surveyed twice, once in 2009 and once in 2013 (2–4 and 6–8 yrs after clear-cutting, respectively). Plant presence was recorded within 100 circular sample plots (radius 1 m) placed evenly throughout each respective clear-cut area along transects spaced 25-m apart. The number of sample plots in which a species was present was taken as a measure of that species' frequency. Random effects meta-analysis, odds ratios and ANCOVA were used to analyse species responses to clear-cutting over time. Results A total of 170 plant species were found in the study, of which 33 were classified as grassland indicator species and 31 as plants primarily confined to forests. Clear-cut areas with a history as meadowland had, on average, up to 64% higher total species richness and 110% more grassland indicator species than did clear-cut areas with a history as forest. The time since clear-cutting had no effect on total species richness. However, the odds of finding a grassland indicator species decreased with the time since clear-cutting, whereas the odds of finding a forest species increased. Conclusions We concluded that land-use history plays an important role in explaining the flora found in Swedish clear-cuts, and that its effects on species richness remain for a minimum of 8 yrs after harvest (conservative estimate). This phenomenon highlights the importance of acknowledging land-use legacies in ecological research and conservation. Future studies should investigate various options for the promotion of grassland plants in clear-cuts with a history of grassland management while also acknowledging the potential conflicts between conservation and production. The results may pertain to other countries with similar land-use histories.
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Neo-nicotinioids are used as insecticides in a variety of crops, e.g. as seed-coating, but have also been found lethal to pollinating insects. In 2013, the European Union introduced a moratorium on some of these compounds. At the same... more
Neo-nicotinioids are used as insecticides in a variety of crops, e.g. as seed-coating, but have also been found lethal to pollinating insects. In 2013, the European Union introduced a moratorium on some of these compounds. At the same time, the Swedish monitoring program NILS (National Inventory of Landscapes in Sweden) had completed its first round and today a second round has been completed. Thus, it is possible to analyze the effect of the moratorium on monitoring data on bumblebees in N=419 sites in southern Sweden. The presence of neo-nicotiniods was assessed using the official records of the type of crop grown on a field (Blockdatabasen), maintained by the Swedish board of Agriculture. The change in bumblebee abundance was compared to the area of different crops in the surrounding landscape. We tested the hypothesis that abundance of bumblebees increased more in landscapes with more oilseed rape (a common crop where seeds previously were coated with neo-nikotinoids). We found no effect on diversity but significant increase in abundance for some species (Bombus pascuorum, B. lucorum) while other did not change (B. terrestris). There was no effect of connectivity of oilseed rape fields in the surrounding landscape, and no evidence of a threshold: it was mostly enough with one field to see an increase after the moratorium. The fact that bumblebee populations recover indicate that the negative effect is mediated directly via the crop. Our study is a nice example of how monitoring data paired with official data can be used for large scale biodiversity studies.peerReviewe
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Abstract With steadily shrinking areas of species-rich semi-natural grasslands in Europe, the management of the remaining fragments becomes ever more crucial for the preservation of key elements of biodiversity in the agricultural... more
Abstract With steadily shrinking areas of species-rich semi-natural grasslands in Europe, the management of the remaining fragments becomes ever more crucial for the preservation of key elements of biodiversity in the agricultural landscape. Detailed knowledge about species-wise, as well as group-wise, relationships can provide guidelines for conservation management and a basis for predictions about different management scenarios. In the present study, we related the occurrence of species of bumblebees (N = 12), butterflies (31) and day-flying moths (4) and their total richness in 424 sites in southern Sweden to three grass sward attributes, (i) flower abundance, (ii) height of the grass sward and (iii) within-site variation in height of vegetation. The abundance of nectar-bearing flowers proved overall the best predictor of richness and in most of the occurrence-based species-wise models. However, both high grass sward height and high variation in grass sward height contributed significantly to species richness and occurrence of individual species. There was a tendency for bumblebees to respond less positively to flower abundance and vegetation height than butterflies and moths. One expectation was that grassland specialists, red-listed species, or species decreasing in other part of Europe, would be more responsive to tall vegetation or flower abundance but there was no support for this in the data. Hence, management strategies that promote common species will also benefit all, or most of, the rare ones as well.
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Research Interests: Geography, Biology, Ecology, Biodiversity, Canopy, and 4 moreHabitat, Transect, Mediterranean Climate, and Basal Area
This article briefly describes the success of the knowledge-transfer reform within medicine known as evidence-based medicine. In this field, the idea is that any decision about an intervention, or lack thereof, should be based on the best... more
This article briefly describes the success of the knowledge-transfer reform within medicine known as evidence-based medicine. In this field, the idea is that any decision about an intervention, or lack thereof, should be based on the best available knowledge. The current move towards a similar reform within nature conservation is reviewed, and its differences with medicine discussed. If "evidencebased conservation" is broadly accepted among researchers, practitioners and NGOs, it might lead to a more consistent protocol for reporting case studies trying interventions and, in the long run, a more efficient use of limited resources for conservation.
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Summary Seeds of Anthriscus sylvestris have physiologically dormant, underdeveloped embryos; thus, they have morphophysiological dormancy (MPD). Germination is delayed until loss of physiological and of morphological (embryo growth)... more
Summary Seeds of Anthriscus sylvestris have physiologically dormant, underdeveloped embryos; thus, they have morphophysiological dormancy (MPD). Germination is delayed until loss of physiological and of morphological (embryo growth) dormancy has occurred. Responses of seeds and embryos to warm (25/15 °C) and cold (1 °C) stratification and to gibberellic acid (GA3) were investigated to determine which one of the eight types of MPD is found in seeds of this species. Cold stratification was the only requirement for loss of MPD, and embryo growth occurred during this treatment. Further, GA3 did not promote loss of MPD. Thus, seeds have deep complex MPD. Nondormant seeds germinated equally well at 15/5 (or 15/6), 20/10 and 25/15 °C, but at each temperature regime germination was higher in light than in darkness. After 16 weeks of cold stratification in darkness at 1 °C, 70% of the seeds germinated during a 2-week period in darkness at 15/5 °C. Thus, in situ germination, especially in spring following seed dispersal, could result in rapid depletion of seeds buried in the soil.
Research Interests: Botany, Biology, Seed dormancy, Flora, Darkness, and 4 moreApiaceae, Germination, Dormancy, and Gibberellic Acid
Responses to climate change have often been found to lag behind the rate of warming that has occurred. In addition to dispersal limitation potentially restricting spread at leading range margins, the persistence of species in new and... more
Responses to climate change have often been found to lag behind the rate of warming that has occurred. In addition to dispersal limitation potentially restricting spread at leading range margins, the persistence of species in new and unsuitable conditions is thought to be responsible for apparent time‐lags. Soil seed banks can allow plant communities to temporarily buffer unsuitable environmental conditions, but their potential to slow responses to long‐term climate change is largely unknown. As local forest cover can also buffer the effects of a warming climate, it is important to understand how seed banks might interact with land cover to mediate community responses to climate change. We first related species‐level seed bank persistence and distribution‐derived climatic niches for 840 plant species. We then used a database of plant community data from grasslands, forests and intermediate successional habitats from across Europe to investigate relationships between seed banks and t...
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We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature,... more
We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other nationa...
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ObjectivesTo examine similarities and dissimilarities in patient and family caregiver dyads in their experience of stress, support, and sense of security.Methods144 patients and their family caregivers participated. Patients were admitted... more
ObjectivesTo examine similarities and dissimilarities in patient and family caregiver dyads in their experience of stress, support, and sense of security.Methods144 patients and their family caregivers participated. Patients were admitted to six Swedish specialist palliative home care units and diagnosed with a non-curable disease with an expected short survival. We analysed similarity patterns of answers within dyads (correlations) as well as dissimilarities, expressed as the difference between within-dyad responses. The latter were subjected to a model-building procedure using GLM, with 13 sociodemographic and clinical characteristics as independent variables.ResultsWithin dyads, patients and family caregivers scored similar in their perception of support and sense of security with care. There was also dissimilarity within dyad responses in their perception of stress and support that could be attributed to sociodemographic or clinical characteristics. When patients scored higher l...
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AimClimate and land use are key determinants of biodiversity, with past and ongoing changes posing serious threats to global ecosystems. Unlike most other organism groups, plant species can possess dormant life‐history stages such as soil... more
AimClimate and land use are key determinants of biodiversity, with past and ongoing changes posing serious threats to global ecosystems. Unlike most other organism groups, plant species can possess dormant life‐history stages such as soil seed banks, which may help plant communities to resist or at least postpone the detrimental impact of global changes. This study investigates the potential for soil seed banks to achieve this.LocationEurope.Time period1978–2014.Major taxa studiedFlowering plants.MethodsUsing a space‐for‐time/warming approach, we study plant species richness and composition in the herb layer and the soil seed bank in 2,796 community plots from 54 datasets in managed grasslands, forests and intermediate, successional habitats across a climate gradient.ResultsSoil seed banks held more species than the herb layer, being compositionally similar across habitats. Species richness was lower in forests and successional habitats compared to grasslands, with annual temperatur...
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To maintain the high biodiversity and preserve the conservation value of semi-natural grasslands, management like grazing or mowing is necessary. Given the limited resources available for management, and few remaining areas, the best... more
To maintain the high biodiversity and preserve the conservation value of semi-natural grasslands, management like grazing or mowing is necessary. Given the limited resources available for management, and few remaining areas, the best management method and intensity should be used. However, the evaluation and comparison of effects of different management intensities on a larger scale is often challenging, as most studies have a limited scope (e.g. only investigating effects in one grassland or for one type of organism). In view of this, we used meta-analysis methods to explore effects of different mowing intensities on biodiversity on a European scale, to reach more robust conclusions. We included studies examining effects of annual mowing compared to both more and less frequent mowing, e.g. twice a year or every other year, on European grassland flora and fauna. Our results suggest that mowing more frequently than once per year has a more positive effect on grassland biodiversity, especially in more productive grasslands. However, differences in effects between frequencies were small, suggesting that mowing more seldom could be a viable management option. This meta-analysis is an example of how ecological knowledge can be compiled to contribute to evidence-based conservation policy and more cost-effective management.peerReviewe
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Abstract Butterfly conservation in Europe is mainly focused on well-defined grassland habitat patches. Such an approach ignores the impact of the surrounding landscape, which may contain complementary resources and facilitate dispersal.... more
Abstract Butterfly conservation in Europe is mainly focused on well-defined grassland habitat patches. Such an approach ignores the impact of the surrounding landscape, which may contain complementary resources and facilitate dispersal. Here, we investigated butterfly species richness and abundance in a habitat normally regarded as unsuitable matrix: production forestry clear-cuts. Butterflies were recorded in 48 clear-cuts in southern Sweden differing with regards to the time since clear-cutting and land-use history (meadow or forest based on historical maps from the 1870s). All clear-cuts had been managed as production forests for at least 80–120 years. A total of 39 species were found in clear-cuts of both land-use histories, but clear-cuts with a history as meadow had on average 34% higher species richness and 19% higher abundance than did clear-cuts with a history as forest. No effect of the time since clear-cutting was found, irrespective of land-use history, which was likely due to the narrow timespan sampled (
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Methane (CH4) emissions via emergent aquatic macrophytes can contribute substantially to the global CH4 balance. We addressed temporal variability in CH4 flux by using the static chamber approach to quantify fluxes from plots dominated by... more
Methane (CH4) emissions via emergent aquatic macrophytes can contribute substantially to the global CH4 balance. We addressed temporal variability in CH4 flux by using the static chamber approach to quantify fluxes from plots dominated by two species considered to differ in flux transport mechanisms (Phragmites australis, Carex rostrata). Temporal variability in daily mean emissions from early June to early October was substantial. The variable that best explained this variation was air temperature. Regular and consistent diel changes were absent and therefore less relevant to include when estimating or modelling CH4 emissions. Methane emissions per m(2) from nearby plots were similar for Phragmites australis and Carex rostrata indicating that CH4 production in the system influenced emissions more than the species identity. This study indicates that previously observed diel patterns and species-effects on emissions require further evaluation to support improved local and regional CH...
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Old living oaks (Quercus robur) are known as a very species-rich habitat for saproxylic beetles, but it is less clear to what extent such veteran trees differ from an even rarer feature: downed trunks of large oaks. In this study, we set... more
Old living oaks (Quercus robur) are known as a very species-rich habitat for saproxylic beetles, but it is less clear to what extent such veteran trees differ from an even rarer feature: downed trunks of large oaks. In this study, we set out to sample this habitat, using window traps, with two aims: (1) to describe the variation of assemblages among downed trunks of different type and (2) to compare beetles on downed oaks with data from veteran standing trees. The results showed that trunk volume and sun exposure better explained assemblages as well as species numbers on downed trunks than did decay stage. Furthermore, species classified as facultative saproxylic species showed weak or no differentiation among downed trunks. Species with different feeding habits showed no apparent differentiation among downed trunks. Furthermore, species composition on dead, downed oak trunks differed sharply from that of living, veteran oaks. Wood or bark feeders were more common on veterans than d...
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ABSTRACT Hydraulic tracer studies are frequently used to estimate wetland residence time distributions (RTDs) and ultimately pollutant removal. However, there is no consensus on how to analyse these data. We set out to (i) review the... more
ABSTRACT Hydraulic tracer studies are frequently used to estimate wetland residence time distributions (RTDs) and ultimately pollutant removal. However, there is no consensus on how to analyse these data. We set out to (i) review the different methods used and (ii) use simulations to explore how the data analysis method influences the quantification of wetland hydraulics and pollutant removal. The results showed that the method influences the water dispersion (N) most strongly and the removal least strongly. The influence increased with decreasing effective volume ratio (e) and N, indicating a greater effect of the method in wetlands with low effective volume and high dispersion. The method of moments with RTD truncation at 3 times the theoretical residence time (t(n)) and tracer background concentration produced the most dissimilar parameters. The most similar parameters values were those for gamma modelling and the method of moments with RTD truncation at tracer background concentration. For correct removal estimates, e was more important than N. However, the results from the literature review and simulations indicated that previously published articles may contain overestimated e and underestimated N values as a result of frequent RTD truncations at 3t(n), when using the method of moments. As a result, the removal rates may also be overestimated by as much as 14% compared to other truncation methods or modelling. Thus, it is recommended that wetland hydraulic tracer studies should use the same method, specifically, RTD truncation. We conclude that the choice of tracer data analysis method can greatly influence the quantifications of wetland hydraulics and removal rate.