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  • 1.
    Bergman, Karl-Olof
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    Ek, Tommy
    Johanneson, Jens
    Jonsson, Sofia
    Westerberg, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    Brist- och funktionalitetsanalys -Östergötlands eklandskap2007Report (Other academic)
  • 2.
    Bergner, Adam
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Avci, Mustafa
    Faculty of Forestry, Süleyman Demirel University, Isparta, Turkey.
    Eryigit, Hasan
    Isparta Province Forest District Directorate, Isparta, Turkey.
    Jansson, Nicklas
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Niklasson, Mats
    Southern Swedish Forest Research Centre, SLU, Alnarp, Sweden.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Influences of forest type and habitat structure on bird assemblagesof oak (Quercus spp.) and pine (Pinus spp.) stands in southwesternTurkey2015In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 336, p. 137-147Article in journal (Refereed)
    Abstract [en]

    The Mediterranean basin exhibits a multitude of forest habitats affected by former and current exploitation and management. Recent afforestation programs have resulted in an increase in the proportion of coniferous trees, while oak stands, formerly utilized for coppicing and grazing, are abandoned or converted into coniferous plantations. The loss of oak stands might negatively affect birds dependent upon broadleaved forests. Studies confirming or rejecting that statement are scarce, particularly in the eastern part of the region. Using a study area in southwestern Turkey we applied a guild-based approach to investigate how pine and oak stands across a chronosequence differ in their capacity to support forest bird assemblages. Variables describing the vegetation were sampled to characterize the stands and relate bird assemblages to stand structure. Bird abundance and species richness was positively associated with age for both stand types. Richness and diversity was highest in oak stands, while there were no differences in bird abundance between the two forest types. Pine stands supported a different bird species composition compared to oak stands of the same age. Stand age and structure, rather than forest type, held the highest explanatory powers for bird assembly structure. Primary cavity-nesters and ground-nesters were more abundant in oak stands, possibly reflecting differences in stand structure and resource distribution. To support these birds with suitable habitats, oaks stands need conservation. Management practices in pine stands should strive for increasing the amount of old trees and retain vegetation in the understory to benefit breeding birds.

  • 3.
    Bergstedt, Johan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    In the eye of the beholder: bias and stochastic variation in cover estimates2009In: PLANT ECOLOGY, ISSN 1385-0237, Vol. 204, no 2, p. 271-283Article in journal (Refereed)
    Abstract [en]

    Cover estimates by eye is a prevailing method to assess abundance. We examined cover estimates with regard to bias and random variation. Ten observers working with a national forest vegetation survey estimated sixteen 100 m(2)-plots, placed in two different vegetation types. These had similar species composition but were clearly distinguishable in the field. In species-wise analyses, observer bias varied greatly, with Dicranum spp., Vaccinium vitis-idaea and Vaccinium myrtillus having the largest bias. Experience had a surprisingly small impact on variation. Power analysis revealed only small differences between observers in the ability to distinguish the two vegetation types, and little value in averaging the assessments from two, three or four observers. Cover estimates did better than presence/absence data in separating the two vegetation types and multivariate analyses were more powerful than univariate ones.

  • 4.
    Blixt, Torbjörn
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Jonason, Dennis
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Clear-cuts in production forests: From matrix to neo-habitat forbutterflies2015In: Acta Oecologica, ISSN 1146-609X, E-ISSN 1873-6238, Vol. 69, p. 71-77Article in journal (Refereed)
    Abstract [en]

    Butterfly conservation in Europe is mainly focused on well-defined grassland habitat patches. Such anapproach ignores the impact of the surrounding landscape, which may contain complementary resourcesand facilitate dispersal. Here, we investigated butterfly species richness and abundance in a habitatnormally regarded as unsuitable matrix: production forestry clear-cuts. Butterflies were recorded in 48clear-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 productionforests for at least 80e120 years. A total of 39 species were found in clear-cuts of both land-usehistories, 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-cuttingwas found, irrespective of land-use history, which was likely due to the narrow timespan sampled (<8years). The absence of temporal effect suggests that clear-cuts may provide butterflies with valuableresources for 10e15 years. Assuming a 100 year forest rotational cycle, this means that 10e15% of thetotal forested area are made up by clear-cuts valuable to butterflies, which corresponds to an area aboutfour times as large as that of species-rich semi-natural grasslands. The study illustrates the importance ofconsidering land-use legacies in ecological research and question the landscape-ecological view thatclear-cuts make up an unsuitable matrix for butterflies. Moreover, forest conservation management withspecial attention to land-use history may increase the quality of the landscape, thus facilitating butterflymetapopulation persistence. Given their large area and assets of nectar and host plant resources, clearcutsmust be considered as a butterfly habitat in its own right. Being a man-made environment withshort history, we might call it a neo-habitat.

  • 5.
    Burman, Joseph
    et al.
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 230 53 Alnarp, Sweden/Ecology Research Group, Canterbury Christ Church University, Canterbury, Kent, CT1 1QU, England, UK .
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Ostrow, Suzanne
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Ryrholm, Nils
    University of Gävle, 801 76 Ga¨vle, Sweden.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Winde, Inis
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences,Alnarp, Sweden, Department of Biology, Lund University, So¨lvegatan 37, 223 62 Lund, Sweden.
    Nyabuga, Franklin N.
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 230 53 Alnarp, Sweden, Department of Biology, Lund University, So¨lvegatan 37, 223 62 Lund, Sweden.
    Larsson, Mattias C.
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 230 53 Alnarp, Sweden.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Revealing hidden species distribution with pheromones: the caseof Synanthedon vespiformis (Lepidoptera: Sesiidae) in Sweden2016In: Journal of Insect Conservation, ISSN 1366-638X, E-ISSN 1572-9753, Vol. 20, no 1, p. 11-21Article in journal (Refereed)
    Abstract [en]

    Synanthedon vespiformis L. (Lepidoptera:Sesiidae) is considered a rare insect in Sweden, discoveredin 1860, with only a few observations recorded until a sexpheromone attractant became available recently. This studydetails a national survey conducted using pheromones as asampling method for this species. Through pheromonetrapping we captured 439 specimens in Southern Sweden at77 sites, almost tripling the number of previously reportedrecords for this species. The results suggest that S. vespiformisis truly a rare species with a genuinely scattereddistribution, but can be locally abundant. Habitat analyseswere conducted in order to test the relationship betweenhabitat quality and the number of individuals caught. InSweden, S. vespiformis is thought to be associated with oakhosts, but our attempts to predict its occurrence by theabundance of oaks yielded no significant relationships. Wetherefore suggest that sampling bias and limited knowledgeon distribution may have led to the assumption that thisspecies is primarily reliant on oaks in the northern part ofits range, whereas it may in fact be polyphagous, similar toS. vespiformis found as an agricultural pest in Central andSouthern Europe. We conclude that pheromones canmassively enhance sampling potential for this and otherrare lepidopteran species. Large-scale pheromone-basedsurveys provide a snapshot of true presences and absencesacross a considerable part of a species national distributionrange, and thus for the first time provide a viable means ofsystematically assessing changes in distribution over timewith high spatiotemporal resolution.

  • 6.
    Hansson, B.
    et al.
    Department of Animal Ecology, Lund University, Lund SE-223 62, Sweden.
    Westerberg, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    Heterozygosity-fitness correlations within inbreeding classes: Local or genome-wide effects?2008In: Conservation Genetics, ISSN 1566-0621, E-ISSN 1572-9737, Vol. 9, no 1, p. 73-83Article in journal (Refereed)
    Abstract [en]

    Marker-based studies of inbreeding may lead to an enhanced understanding of inbreeding depression in natural populations, which is a major concern in conservation genetics. Correlations between marker heterozygosity and variation in fitness-associated traits-'heterozygosity-fitness correlations' (HFCs)-are of particular importance and have been widely applied in natural populations. In partially inbred populations, HFCs can be driven by selection against inbred individuals and thus reflect inbreeding depression. However, other explanations for HFCs also exist, such as functional effects of the markers per se or that the markers reveal selection on linked fitness genes due to extended linkage disequilibrium (LD) in the population. Accordingly, HFCs do not only arise in partially inbred populations, they may also occur within inbreeding classes such as families, i.e. in situations when there is no variation in the inbreeding coefficient. In this study we focus on the importance of LD for within-family HFCs, thereby aiming at enhancing our general understanding of HFCs. For non-coding markers, within-family HFCs have been proposed to be caused in two ways: either by 'local effects' at linked fitness genes in LD with the markers, or by 'general effects' due to a correlation between proportion of heterozygous markers (H M ) and heterozygosity at genome-wide distributed fitness genes (H GW ). To evaluate these contrasting hypotheses for within-family HFCs, we analysed simulated data sets of sexually reproducing populations with varying levels of LD. The results confirmed that segregation induces variation in both H M and H GW at a fixed level of inbreeding, as expected, the variation in H M declined with increasing number of markers, whereas the variation in H GW declined with decreasing LD. However, less intuitively, there was no positive correlation between the variation in H M and H GW within inbreeding classes when the local component of H GW was accounted for (i.e. when the part of the chromosome in LD with the markers was excluded). This strongly suggests that within-family HFCs are not caused by general effects. Instead, our results support the idea that HFCs at a known level of inbreeding can be driven by local effects in populations with high to moderate LD. Note however that we define the local component of H GW as the part of the chromosomes in LD with the markers. This implies that when LD is high, the local component will consist of a substantial part of the genome and thus provides a rather 'genome-wide' view. We caution against routinely interpreting positive HFCs as evidence of inbreeding depression and non-significant HFCs as lack thereof, especially when few markers are used. © 2007 Springer Science+Business Media, Inc.

  • 7.
    Hansson, B.
    et al.
    Department of Animal Ecology, Ecology Building, Lund University, 223 62 Lund, Sweden.
    Westerberg, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    On the correlation between heterozygosity and fitness in natural populations2002In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 11, no 12, p. 2467-2474Article, review/survey (Refereed)
    Abstract [en]

    Three primary hypotheses currently prevail for correlations between heterozygosity at a set of molecular markers and fitness in natural populations. First, multilocus heterozygosity-fitness correlations might result from selection acting directly on the scored loci, such as at particular allozyme loci. Second, significant levels of linkage disequilibrium, as in recently bottlenecked-and-expanded populations, might cause associations between the markers and fitness loci in the local chromosomal vicinity. Third, in partially inbred populations, heterozygosity at the markers might reflect variation in the inbreeding coefficient and might associate with fitness as a result of effects of homozygosity at genome-wide distributed loci. Despite years of research, the relative importance of these hypotheses remains unclear. The screening of heterozygosity at polymorphic DNA markers offers an opportunity to resolve this issue, and relevant empirical studies have now emerged. We provide an account of the recent progress on the subject, and give suggestions on how to distinguish between the three hypotheses in future studies.

  • 8.
    Jonason, Dennis
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Ibbe, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Tunér, Albert
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Vegetation in clear-cuts depends on previous land use: a century-old grassland legacy2014In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, no 22, p. 4287-4295Article in journal (Refereed)
    Abstract [en]

    Plant species richness in central and northern European seminatural grasslandsis often more closely linked to past than present habitat configuration, which isindicative of an extinction debt. In this study, we investigate whether signs ofhistorical grassland management can be found in clear-cuts after at least80 years as coniferous production forest by comparing floras between clear-cutswith a history as meadow and as forest in the 1870s in Sweden. Study sites wereselected using old land-use maps and data on present-day clear-cuts. Speciestraits reflecting high capacities for dispersal and persistence were used toexplain any possible links between the plants and the historical land use. Clearcutsthat were formerly meadow had, on average, 36% higher species richnessand 35% higher richness of grassland indicator species, as well as a larger overallseed mass and lower anemochory, compared to clear-cuts with history asforest. We suggest that the plants in former meadows never disappeared afterafforestation but survived as remnant populations. Many contemporary forestsin Sweden were managed as grasslands in the 1800s. As conservation of remaininggrassland fragments will not be enough to reduce the existing extinctiondebts of the flora, these young forests offer opportunities for grassland restorationat large scales. Our study supports the concept of remnant populationsand highlights the importance of considering historical land use for understandingthe distribution of grassland plant species in fragmented landscapes, aswell as for policy-making and conservation.

  • 9.
    Lindström, Tom
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology . Linköping University, The Institute of Technology.
    Håkansson, Nina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology .
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    Wennergren, Uno
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology . Linköping University, The Institute of Technology.
    Splitting the tail of the displacement kernel shows the unimportance of kurtosis2008In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 89, no 7, p. 1784-1790Article in journal (Refereed)
    Abstract [en]

    Animals disperse in space through different movement behaviors, resulting in different displacement distances. This is often described with a displacement kernel where the long-distance dispersers are within the tail of the kernel. A displacement with a large proportion of long-distance dispersers may have impact on different aspects of spatial ecology such as invasion speed, population persistence, and distribution. It is, however, unclear whether the kurtosis of the kernel plays a major role since a fatter tail also influences the variance of the kernel. We modeled displacement in landscapes with different amounts and configurations of habitats and handled kurtosis and variance separately to study how these affected population distribution and transition time. We conclude that kurtosis is not important for any of these aspects of spatial ecology. The variance of the kernel, on the other hand, was of great importance to both population distribution and transition time. We argue that separating variance and kurtosis can cast new light on the way in which long-distance dispersers are important in ecological processes. Consequences for empirical studies are discussed.

  • 10.
    Lättman, Håkan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Ecology. Linköping University, The Institute of Technology.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Ecology. Linköping University, The Institute of Technology.
    Rapp, Malin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Tälle, Malin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Ecology. Linköping University, The Institute of Technology.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Ecology. Linköping University, The Institute of Technology.
    Biodiversity in the wake of urban sprawl: loss among epiphytic lichens on large oaksManuscript (preprint) (Other academic)
    Abstract [en]

    Biodiversity often suffers from urbanisation. In the present study, we focused on how the age of urbanisation affects the richness of 17 epiphytic lichens species and their cover on large oaks, with a minimum spacing of 250 m, in urban environments in the city of Linköping (100,000 inhabitants), SE Sweden. We also surveyed trees in adjacent rural areas, selected to have similar distributions of tree trunk circumference and oak density within 300 m. Lichen richness and cover were significantly lower on urban trees compared to rural trees. Furthermore, richness and cover decreased with the length of time that urban trees had been surrounded by houses. Roughly one species is lost every 30 years. Most of the species that were analysed demonstrated a drop in occurrence with respect to the duration of housing development. The reduction in the probability of occurrence varied from 60% (Calicium viride, Evernia prunastri), 80% (Chrysotrix candelaris) to 90% (Ramalina spp.) during the 160-year period of urbanisation considered. Therefore, even if valuable trees survive over the course of development, their lichen flora are likely to become depleted over time.

  • 11.
    Lättman, Håkan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Rapp, Malin
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Tälle, Malin
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Decline in lichen biodiversity on oak trunks due to urbanization2014In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 32, no 4, p. 518-528Article in journal (Refereed)
    Abstract [en]

    Biodiversity often suff ers from urbanization. In the present study, we focused on how the duration of urbanization aff ects therichness of 17 epiphytic lichen species and their cover on large oaks in urban environments in a city of 100 000 inhabitantsin southeast Sweden. We also surveyed trees in adjacent rural areas, selected to have similar distributions of tree trunkcircumference and surrounding oak density (within 300 m). Lichen richness and cover were lower on urban trees comparedto rural trees. Furthermore, richness and cover decreased with the length of time that urban trees had been surrounded byhouses. Most of the species that were analysed demonstrated a decline in occurrence with respect to the duration of housingdevelopment. Th e reduction in the probability of occurrence varied from 60% ( Calicium viride , Evernia prunastri ), 80%( Chrysothrix candelaris ) to 90% ( Ramalina spp.) during the considered 160-year period of urbanization. Th erefore, even ifvaluable trees survive over the course of development, their lichen biota is likely to become depleted over time.

  • 12.
    Milberg, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Cronvall, Erik
    Department of Forest Resource Management, SLU, SE-901 83 Umeå, Sweden.
    Eriksson, Åsa I.
    Department of Forest Resource Management, SLU, SE-901 83 Umeå, Sweden.
    Glimskär, Anders
    Department of Ecology, SLU, Box 7044, SE-750 07 Uppsala, Sweden.
    Islamovic, Azra
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Jonason, Dennis
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Löfqvist, Zandra
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Flower abundance and vegetation height as predictors fornectar-feeding insect occurrence in Swedish semi-natural grasslands2016In: Agriculture, Ecosystems & Environment, ISSN 0167-8809, E-ISSN 1873-2305, Vol. 230, p. 47-54Article in journal (Refereed)
    Abstract [en]

    With steadily shrinking areas of species-rich semi-natural grasslands in Europe, the management of theremaining fragments becomes ever more crucial for the preservation of key elements of biodiversity inthe agricultural landscape. Detailed knowledge about species-wise, as well as group-wise, relationshipscan provide guidelines for conservation management and a basis for predictions about differentmanagement 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 threegrass sward attributes, (i)flower abundance, (ii) height of the grass sward and (iii) within-site variation inheight of vegetation. The abundance of nectar-bearingflowers proved overall the best predictor ofrichness and in most of the occurrence-based species-wise models. However, both high grass swardheight and high variation in grass sward height contributed significantly to species richness andoccurrence of individual species. There was a tendency for bumblebees to respond less positively toflower abundance and vegetation height than butterflies and moths. One expectation was that grasslandspecialists, red-listed species, or species decreasing in other part of Europe, would be more responsive totall vegetation orflower abundance but there was no support for this in the data. Hence, managementstrategies that promote common species will also benefit all, or most of, the rare ones as well.

  • 13.
    Milberg, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Norman, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Pettersson, Roger B.
    Department of Wildlife, Fish and Environmental Studies, SLU, 901 83 Umea°, Sweden.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Wikars, Lars-Ove
    Hovgården 66, Borlänge, Sweden .
    Jansson, Nicklas
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    A burning desire for smoke? Sampling insects favoured by forestfire in the absence of fire2015In: Journal of Insect Conservation, ISSN 1366-638X, E-ISSN 1572-9753, Vol. 19, no 1, p. 55-65Article in journal (Refereed)
    Abstract [en]

    Fire-favoured insects are difficult to sampleexcept opportunistically after forest fires. Here, we tested ifsmoke from a small fire could be an efficient way to samplesuch insects. Insects were sampled over ca. 10 h hours, byhand-picking and netting on screens put up around the fire.Two specimens of the rare and redlisted Hormopeza spp.(Diptera, Empididae) were caught. Large numbers([20,000) of Microsania spp. (Diptera, Platypezidae) werecaught, but none in the absence of smoke. The numbers ofMicrosania spp. clearly peaked in late afternoon, and ashort sampling period would be sufficient if targeting onlythis taxon. Of the almost 200 species of Coleoptera, 17 %were considered as fire-favoured, contributing 9 % of thespecimens, suggesting low efficiency of the method for thisgroup. Using 23 sites differing in fire history, catches ofMicrosania spp. were unaffected by numbers and area offorest fire (preceding 5 years and within 10 km radius overthe sampling sites). In contrast, there was a weak trend forthe proportion of fire-favoured Coleoptera to increase withincreasing number of fires. To conclude, smoke as producedin our study can clearly attract fire-favoured Diptera,but smoke had only a weak effect on fire-favoured Coleopterain the study area. It is still likely that selectivelypicking specimens of species attracted to smoke is a morecost-efficient method than using, e.g., Malaise traps thatcatch indiscriminately.

  • 14.
    Milberg, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    Bergstedt, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    Fridman, Jonas
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Odell, Gunnar
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    Systematic and random variation in vegetation monitoring data2008In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 19, p. 633-644Article in journal (Refereed)
    Abstract [en]

    Question: Detecting species presence in vegetation and making visual assessment of abundances involve a certain amount of skill, and therefore subjectivity. We evaluated the magnitude of the error in data, and its consequences for evaluating temporal trends.

    Location: Swedish forest vegetation.

    Methods: Vegetation data were collected independently by two observers in 342 permanent 100-m2 plots in mature boreal forests. Each plot was visited by one observer from a group of 36 and one of two quality assessment observers. The cover class of 29 taxa was recorded, and presence/absence for an additional 50.

    Results: Overall, one third of each occurrence was missed by one of the two observers, but with large differences among species. There were more missed occurrences at low abundances. Species occurring at low abundance when present tended to be frequently overlooked. Variance component analyses indicated that cover data on 5 of 17 species had a significant observer bias. Observer-explained variance was < 10% in 15 of 17 species.

    Conclusion: The substantial number of missed occurrences suggests poor power in detecting changes based on presence/absence data. The magnitude of observer bias in cover estimates was relatively small, compared with random error, and therefore potentially analytically tractable. Data in this monitoring system could be improved by a more structured working model during field work.

  • 15.
    Milberg, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Tälle, Malin
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, Faculty of Science & Engineering.
    Fogelfors, Håkan
    Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Corrigendum to "The biodiversity cost of reducing management intensity in species-rich grasslands: Mowing annually vs. every third year" [Basic Appl. Ecol. 22 (2017) 61-74]2018In: Basic and Applied Ecology, ISSN 1439-1791, E-ISSN 1618-0089, p. 97-98Article in journal (Refereed)
  • 16.
    Musa, Najihah
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Andersson, Klas
    Swedish University of Agriculture Science, Sweden.
    Burman, Joseph
    Swedish University of Agriculture Science, Sweden.
    Andersson, Fredrik
    Mid Sweden University, Sweden.
    Hedenstrom, Erik
    Mid Sweden University, Sweden.
    Jansson, Niklas
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Paltto, Heidi
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Winde, Inis
    Swedish University of Agriculture Science, Sweden.
    Larsson, Mattias C.
    Swedish University of Agriculture Science, Sweden.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Using Sex Pheromone and a Multi-Scale Approach to Predict the Distribution of a Rare Saproxylic Beetle2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 6Article in journal (Refereed)
    Abstract [en]

    The European red click beetle, Elater ferrugineus L., is associated with wood mould in old hollow deciduous trees. As a result of severe habitat fragmentation caused by human disturbance, it is threatened throughout its distribution range. A new pheromone-based survey method, which is very efficient in detecting the species, was used in the present study to relate the occurrence of E. ferrugineus to the density of deciduous trees. The latter data were from a recently completed regional survey in SE Sweden recording >120,000 deciduous trees. The occurrence of E. ferrugineus increased with increasing amount of large hollow and large non-hollow trees in the surrounding landscape. Quercus robur (oak) was found to be the most important substrate for E. ferrugineus, whereas two groups of tree species (Carpinus betulus, Fagus sylvatica, Ulmus glabra, vs. Acer platanoides, Aesculus hippocastanum, Fraxinus excelsior, Tilia cordata) were less important but may be a complement to oak in sustaining populations of the beetle. The occurrence of E. ferrugineus was explained by the density of oaks at two different spatial scales, within the circle radii 327 m and 4658 m. In conclusion, priority should be given to oaks in conservation management of E. ferrugineus, and then to the deciduous trees in the genera listed above. Conservation planning at large spatial and temporal scales appears to be essential for long-term persistence of E. ferrugineus. We also show that occurrence models based on strategic sampling might result in pessimistic predictions. This study demonstrates how pheromone-based monitoring make insects excellent tools for sustained feedback to models for landscape conservation management.

  • 17. Palmer, MW
    et al.
    McGlinn, D
    Westerberg, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    Milberg, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    Indices for detecting differences in species composition: some simplifications of RDA and CCA2008In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 89, p. 1769-1771Article in journal (Refereed)
    Abstract [en]

    We provide algebraic simplifications for the redundancy analysis (RDA) eigenvalue and the canonical correspondence analysis (CCA) eigenvalue in the special case of permanent plots sampled twice. The indices for RDA and CCA are interrelated and are intuitively interpretable. These simplifications also apply to simple split-plot designs and to a balanced design with two independent samples.

  • 18.
    Tälle, Malin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Paltto, Heidi
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Pihlgren, Aina
    Swedish Biodiversity Centre, Swedish University of Agricultural Sciences and Uppsala University, Sweden.
    Svensson, Roger
    Swedish Biodiversity Centre, Swedish University of Agricultural Sciences and Uppsala University, Sweden.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Wissman, Jörgen
    Swedish Biodiversity Centre, Swedish University of Agricultural Sciences and Uppsala University, Sweden.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Mowing for biodiversity: grass trimmer and knife mower perform equally well2014In: Biodiversity and Conservation, ISSN 0960-3115, E-ISSN 1572-9710, Vol. 23, no 12, p. 3073-3089Article in journal (Refereed)
    Abstract [en]

    Mowing of semi-natural grasslands is an important management method to maintain the conservation value and species-richness of this habitat. Mowing using cutting instruments, e.g. sickle bar mowers, is thought to be superior by practitioners compared with other mechanical instruments that tears off the plant material, e.g. grass trimmers. However, almost no studies exist that supports this assumption. We analysed a 12-year field trial in a semi-natural grassland in south-eastern Sweden, with the aim of determining which mowing technique best maintains the conservation value of semi-natural grasslands. Two mowing techniques were compared: mowing using a hand-pushed sickle bar mower (a type of knife mower), or mowing using a grass trimmer at a 5-cm or 0-cm cutting height. The odds that a recorded species belongs to a group of indicator species were calculated for sample plots, and odds ratios were calculated contrasting treatments. Three types of indicator species classification systems were used: (i) indicators of management for species richness, (ii) indicators of excess nitrogen and (iii) indicators of lack of management. The odds ratios were calculated for years 1–5, 7 and 12 of the trial. In addition, Principal Response Curve analysis was performed to analyse the change in vegetation composition over time and ANOVA for plant species richness in plots. The results showed that over time there were no differences in the odds of finding indicators of any of the three types, for any of the mowing techniques. Furthermore, there were no apparent change in vegetation composition and only a small effect on richness. These results suggest that mowing using a sickle bar mower or a grass trimmer had the same effect on the floristic composition of grasslands, and both techniques can be recommended for use in semi-natural grasslands.

  • 19.
    Tälle, Malin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, Faculty of Science & Engineering.
    Deak, Balazs
    Univ Debrecen, Hungary.
    Poschlod, Peter
    Univ Regensburg, Germany.
    Valko, Orsolya
    MTA DE Biodivers and Ecosyst Serv Res Grp, Hungary.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Similar effects of different mowing frequencies on the conservation value of semi-natural grasslands in Europe2018In: Biodiversity and Conservation, ISSN 0960-3115, E-ISSN 1572-9710, Vol. 27, no 10, p. 2451-2475Article, review/survey (Refereed)
    Abstract [en]

    Both agricultural intensification and abandonment have led to the loss of European semi-natural grasslands. Nature conservation management measures like mowing are essential for preserving the biodiversity of remaining grasslands. However, there are no conclusive results from studies examining effects of different mowing frequencies across Europe. To fill this gap, we evaluated data from European studies comparing mowing frequencies to determine which are the most beneficial from a nature conservation viewpoint. We searched literature for short- and long-term studies comparing the effects of different mowing frequencies on outcome measures relevant for biodiversity conservation. We found 29 relevant studies where mowing once per year was compared to higher or lower mowing frequencies. The studies covered various grassland types and organisms. The effects were analysed using response ratios, where mowing once per year, i.e. the traditional mowing frequency in semi-natural grasslands, was compared to mowing every fifth, third or second year and mowing two, three or four times a year. Overall, we found similar effects of the different mowing frequencies on the biodiversity of flora and fauna. More frequent mowing generally had a more positive effect, but differences between frequencies were small. Effects were habitat-specific, differing between site and study conditions. For example, a higher mowing frequency was more beneficial in more productive grasslands. These results suggest that in most European semi-natural grasslands, mowing less frequently is a way of using the limited funds available for management more efficiently while still maintaining grassland conservation values, but e.g. site productivity must be considered when determining a suitable mowing frequency.

  • 20.
    Tälle, Malin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Deák, Balázs
    MTA-DE Biodiversity and Ecosystem Services Research Group, Egytem tér 1, Debrecen H-4032, Hungary.
    Poschlod, Peter
    Ecology and Conservation Biology, Institute of Plant Sciences, University of Regensburg, D-93040 Regensburg, Germany.
    Valkó, Orsolya
    University of Debrecen, Department of Ecology, P.O. Box 71, Debrecen H-4010, Hungary.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Grazing vs. mowing: A meta-analysis of biodiversity benefits forgrassland management2016In: Agriculture, Ecosystems & Environment, ISSN 0167-8809, E-ISSN 1873-2305, Vol. 222, p. 200-212Article, review/survey (Refereed)
    Abstract [en]

    To maintain the high biodiversity of semi-natural grasslands, management by grazing or mowing isneeded. Given the limited resources and few remaining areas, the best management method should beused. However, only a few studies comparing the effects of mowing and grazing on grassland biodiversityexists. Therefore, the goal of the present review was to extract as much data as possible from theliterature and evaluate them using a meta-analysis approach. We searched scientific and grey literaturefor studies comparing the effects of grazing and annual mowing on outcomes relevant for biodiversityconservation. We identified 35 relevant studies on grazing and annual mowing that provided datasuitable for the meta-analysis. We found that grazing generally had a more positive effect on theconservation value of semi-natural grasslands compared to mowing, but effect sizes were generally smallto moderate for most contrasts. Furthermore, effects varied across some grassland characteristics e.g. fordifferent grassland types, with grazing and mowing having a similar effect or mowing having a morepositive effect in certain cases. Our results suggest, that in most cases grazing should be the preferredmanagement method when managing for grassland conservation.

  • 21.
    Tälle, Malin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Fogelfors, Håkan
    Dept of Crop Production Ecology, Swedish Univ. of Agricultural Sciences, Box 7043, SE-750 07 Uppsala, Sweden.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    The conservation benefit of mowing vs grazing for management ofspecies-rich grasslands: a multi-site, multi-year field experiment2015In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 33, no 6, p. 761-768Article in journal (Refereed)
    Abstract [en]

    Species-rich semi-natural grasslands in Europe are becoming more fragmented and many species that depend on thishabitat type are rare and threatened today. Management methods like mowing and grazing are needed to preserve remaininggrasslands. Because management is costly it is important to use the most cost-effective as well as the most beneficialmanagement method, but few studies have compared mowing and grazing. We investigated the effect of mowing andgrazing on grassland vegetation using data from 11 long-term field trials situated in southern Sweden. We calculated thechange in the odds of finding species belonging to three different groups of indicators at the start of the treatment and after8 and 14 years. The used indicator groups were indicators of good management, excess nitrogen and poor management.The results revealed an increase in the odds of finding indicators of good management in mowed plots and an increasein finding indicators of excess nitrogen in grazed plots. The odds of finding indicators of poor management remainedunchanged. Results from sub-analysis of the grazing intensity showed a more negative effect from grazing with low grazingintensity than normal/high grazing intensity. Therefore, mowing is the best long-term management method for seminaturalgrasslands in Sweden and grazing using a low grazing intensity should be avoided.

  • 22.
    Westerberg, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    Lindström, Tom
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology .
    Nilsson, E.
    Wennergren, Uno
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology .
    The effect on dispersal from complex correlations in small-scale movement2008In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 213, no 2, p. 263-272Article in journal (Refereed)
    Abstract [en]

    Calculations of large-scale displacement distances were made to evaluate the combined effect of small-scale movement pattern of a Collembola, Protaphorura armata. The effect of presence of food and conspecific density on turning angle, step length and activity/motility was investigated. Calculations of net square displacement were made both by assuming correlated random walk (CRW) and by resampling data to account for correlation structures in movement patterns that violate the assumptions of CRW. In presence of food, individuals spent less time moving (decreased activity), but when they moved they showed larger turning angles than individuals moving in areas without food. Increased conspecific density did not affect time spent moving by individuals, but when step length decreased and turning angle increased. P. armata showed negative density-dependent dispersal and exhibited area-restricted search as a response to both food and increased conspecific density. The CRW was relatively robust to some violations of its underlying assumptions. However, the expected displacement increased substantially, as much as 50%, when accounting for observed auto-correlation in step length and correlation between step length and turning angle. Hence, an explanation for increased displacement and dispersal of a species can also be the result of a more complex correlation of its behaviour rather than solely altering specific movement parameters, for example increasing step length or decreasing turning angle. The results emphasise the importance of careful analysis of small-scale movement before using them as predictors of population distribution and invasion speed in heterogeneous landscapes. © 2007 Elsevier B.V. All rights reserved.

  • 23.
    Westerberg, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology.
    Wennergren, Uno
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology.
    Matrix models: A tool for landscape management2005In: New trends in ecology research / [ed] Burk, A. R, New York: Nova Science Publisher, Inc. , 2005, p. 135-158Chapter in book (Other academic)
    Abstract [en]

    Ecology is the study of the interrelationships between organisms and their environment, including the biotic and abiotic components. There are at least six kinds of ecology: ecosystem, physiological, behavioural, population, and community. Specific topics include: acid deposition, acid rain revisited, biodiversity, biocomplexity, carbon sequestration in soils, coral reefs, ecosystem services, environmental justice, fire ecology, floods, global climate change, hypoxia, and invasion. This new book presents new research on ecology from around the world.

  • 24.
    Westerberg, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    Wennergren, Uno
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology .
    Predicting the spatial distribution of a population in a heterogeneous landscape2003In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 166, no 1-2, p. 53-65Article in journal (Refereed)
    Abstract [en]

    A spatially explicit, population-based density-independent matrix model was used to analyse the effect of landscape composition on the spatial asymptotic distribution of a population. The landscape was considered being continuous rather than consisting of patches. The redistribution of a population was viewed in a simplistic way, and modelled using a response function to local landscape quality and a displacement function. Hence, the approach is suitable for landscape ecologists. Some of the analytical methods from non-negative matrix theory were used to determine the differences between the asymptotical spatial population distribution (the dominating right eigenvector of the movement matrix) and the randomly arranged resources. The results showed that the amount and quality of poor habitats had the greatest impact on matching between population and resource distribution. The results on matching between population and resource distribution are discussed in relation to designing reserves for endangered species and in the biocontrol of pest species in agricultural systems. © 2003 Elsevier Science B.V. All rights reserved.

  • 25.
    Westerberg, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Ecology .
    Östman, Örjan
    Wennergren, Uno
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology .
    Movement effects on equilibrium distributions of habitat generalists in heterogeneous landscapes2005In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 188, no 2-4, p. 432-447Article in journal (Refereed)
    Abstract [en]

    The effect of landscape heterogeneity on population distribution and persistence has been well investigated for habitat specialists, but the response of habitat generalist to landscape heterogeneity is less well known. We used a matrix model for an agricultural habitat generalist carabid (Pterostichus cupreus (L.)) on a lattice landscape, to study the effect of changing landscape composition and configuration on the within generation equilibrium (asymptotic) population distribution. Movements were approximated from diffusion functions that depended on habitat quality only. The population distribution of P. cupreus was sensitive to both habitat composition and configuration. Habitat configuration generally explained more variation in the population distribution relative the resources, but the changes in amount of preferred habitat had a larger effect at low amounts of preferred habitat. The resource use of P. cupreus was less sensitive when there was low contrast between habitat qualities. Numerical solutions indicated that the stable population distribution is usually reached within a generation, and the analytical results from our equilibrium model are thus reasonable approximations. The (transient) time to reach equilibrium population distribution was lower in landscapes where preferred habitat was scarce and scattered, and there was a trade-off between transient time and the population distribution relative to the resources. We found no clear threshold effects, only a gradually steeper decline in resource use as preferred resources were randomly lost in high contrast landscapes. Overall, the results were congruent with other results on generalists where demography and density dependent processes have been included, which indicate that movement alone is a driving force. © 2005 Elsevier B.V. All rights reserved.

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