| 11. |
- Milberg, Per, et al.
(author)
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Assemblages of flower-visiting insects in clear-cuts are rich and dynamic
- 2021
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In: European Journal of Entomology. - : Akademie Ved Ceske Republiky Entomologicky Ustav,Czech Academy of Sciences, Institute of Entomology. - 1210-5759 .- 1802-8829. ; 118, s. 182-191
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Journal article (peer-reviewed)abstract
- Clear-cuts in production forests provide an open, sunny environment, with an abundance of nectar, as well as exposed soil and woody debris. This makes them a potential habitat for several groups of insects that typically use open habitats like grassland, including those species that visit flowers. In the current study, we used colour pan traps to catch flower-visiting species. Study sites were selected according to age (2-8 yrs since clear-cut) and land-use history (forest or meadow 150 yrs ago). We caught and identified solitary bees (395 specimens belonging to 59 species), social bees (831/16), other Hymenoptera (367/66), Syrphidae (256/31), and beetles (Lepturinae & Cetoniinae; 11,409/12). Age of the clear-cut strongly affected species composition as well as several groups and species, with most species caught mainly in the younger clear-cuts. Flower abundance statistically affected several groups and species, but inferring causation is difficult due to the flower-richness bias in pan trap catches. Bare soil and woody debris were important for the insect assemblage sampled, while bare rock was not. Although the majority of the insects caught were forest species, about one third of the species were associated with open, agricultural sites and hence seem to be able to locate and exploit resources in clear-cuts.
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| 12. |
- Milberg, Per, 1959-, et al.
(author)
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Assemblages of flower-visiting insects in clear-cuts are rich and dynamic
- 2021
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Other publicationabstract
- Clear-cuts in production forests provide an open, sunny environment, with an abundance of nectar, as well as exposed soil and woody debris. This makes them a potential habitat for several groups of insects that typically use open habitats like grassland, including those species that visit flowers. In the current study, we used colour pan traps to catch flower-visiting species. Study sites were selected according to age (2-8 yrs since clear-cut) and land-use history (forest or meadow 150 yrs ago). We caught and identified solitary bees (395 specimens belonging to 59 species), social bees (831/16), other Hymenoptera (367/66), Syrphidae (256/31), and beetles (Lepturinae & Cetoniinae; 11,409/12). Age of the clear-cut strongly affected species composition as well as several of the groups and species, with most species caught mainly in the younger clear-cuts. Flower abundance statistically affected several groups and species, but such effects are potentially suspect due to the flower-richness bias in pan trap catches. Bare soil and woody debris seemed irrelevant were important for the insect assemblage sampled, while bare rock sometimes positively affected flower-visiting insectswas not. Although the majority of the insects caught were forest species, about one third of the species were associated with open, agricultural sites and hence seem to be able to locate and exploit resources in clear-cuts.
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| 13. |
- Milberg, Per, et al.
(author)
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How spruce and pine fare in a wooded meadow without management for a century
- 2024
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In: Baltic Forestry. - : INST FORESTRY LRCAF. - 1392-1355 .- 2029-9230. ; 30:1
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Journal article (peer-reviewed)abstract
- Spruce ( Picea abies) ) and pine ( Pinus sylvestris) ) dominate much of Scandinavia, but it is unclear how these species fare in places not subjected to forestry. Currently, evidence suggests that in the absence of disturbance, spruce will increase while pine will decrease. The term "sprucification" has been coined to describe the landscape-wise change. We tested this prediction in a 3.4 ha wooded meadow in southern Sweden set aside for free development in 1923. Comparing with older data, we assessed how tree density, basal area and size distribution has changed since 1937 when trees were mapped. We also estimated annual mortality and recruitment of new trees. The number of trees had declined since 1937, while the basal area had increased somewhat. Spruce but not pine had shifted its geographic distribution within the reserve. Mortality was three times higher among spruce than pine. Recruitment of new trees was modest, with most being spruce. Size distribution of spruce changed substantially over time with a loss of small trees and addition of large trees. Size distribution of pine, however, remained unaffected, except for the decline in the number of small trees. On balance, despite a century of free development, there was no clear evidence for sprucification in this former wooded meadow, now a dense mixed forest.
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| 14. |
- Milberg, Per, et al.
(author)
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Maintaining an open landscape: Comparison of management methods for semi-natural grasslands: A Swedish multi-site study
- 2023
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In: Global Ecology and Conservation. - : ELSEVIER. - 2351-9894. ; 48
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Journal article (peer-reviewed)abstract
- Traditional management of semi-natural grasslands by grazing or annual mowing is not always feasible and the current study set out to evaluate alternative management methods. At eleven locations in southern Sweden, block experiments were conducted evaluating seven treatments in 5 m*20 m plots: grazing, annual mowing, annual spring burning, mowing every third year, mechanical removal of woody plants, herbicide control of woody plants, and untreated control. After approximately 13 years, trends for woody plants and species richness, and the occurrence of management-dependent plant species, low-grown species, and pollinator-attracting plant species were analysed. Overall, the annual mowing and grazing treatments resulted in fewer woody plants, the highest species richness, and more management-dependent, low-grown, and pollinator-attracting species. The untreated control plots showed the opposite effect, whereas less intense management (annual burning, mowing every third year, and mechanical and chemical treatments of woody plants) showed mixed and often intermediate effects. Compared to grazing and mowing, less intense management methods do not constitute long-term management alter-natives to preserve typical features of species-rich grasslands. However, they may be short-term alternatives at sites where the recruitment of woody species is absent or rare. However, to prevent the encroachment of woody species, less intensive management might be a better long-term alternative at more productive sites with slow or inhibited woody species recruitment.
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| 15. |
- Milberg, Per, et al.
(author)
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Pollinator activity and flowering in agricultural weeds in Sweden
- 2024
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In: Ecology and Evolution. - : WILEY. - 2045-7758. ; 14:7
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Journal article (peer-reviewed)abstract
- The extent to which weeds in arable land are useful to pollinators depends in part on the temporal pattern of flowering and insect flight activity. We compiled citizen science data on 54 bees and hoverflies typical of agricultural areas in southern Sweden, as well as 24 flowering weed species classified as pollinator-friendly in the sense that they provide nectar and/or pollen to pollinators. The flight periods of the bees and hoverflies varied greatly, but there were also some consistent differences between the four groups studied. The first group to fly were the early flying solitary bees (7 species), followed by the social bees (18 species). In contrast, other solitary bees (11 species) and hoverflies (22 species) flew later in the summer. Solitary bees had the shortest flight periods, while social bees and hoverflies had longer flight periods. Flowering of weed species also varied greatly between species, with weeds classified as winter annuals (e.g., germinating in autumn) starting early together with germination generalists (species that can germinate in both autumn and spring). Summer annuals (spring germinators) and perennials started flowering about a month later. Germination generalists had a much longer flowering period than the others. Weekly pollinator records were in most cases significantly explained by weed records. Apart from early flying solitary bees, all models showed strong positive relationships. The overall best explanatory variable was the total number of weeds, with a weight assigned to each species based on its potential as a nectar/pollen source. This suggests that agricultural weeds in Sweden provide a continuous potential supply of nectar and pollen throughout the flight season of most pollinators. The usefulness of weeds to pollinators depends partly on the temporal pattern of flowering and flight activity. We compiled citizen science data on observation of bees and hoverflies typical of agricultural areas in southern Sweden, as well as flowering of weed species classified as pollinator-friendly. Flight periods among the 54 pollinator species varied greatly among species as did flowering among the weeds. Data suggest that agricultural weeds in Sweden provide a continuous supply of nectar and pollen throughout the flight season for all pollinators except early-flying solitary bees.image
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| 16. |
- Milberg, Per, et al.
(author)
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Site factors are more important than management for indicator species in semi-natural grasslands in southern Sweden
- 2020
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In: Plant Ecology. - : SPRINGER. - 1385-0237 .- 1573-5052. ; 221:7, s. 577-594
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Journal article (peer-reviewed)abstract
- Management of semi-natural grasslands is essential to retain the characteristic diversity of flora and fauna found in these habitats. To maintain, restore or recreate favourable conditions for grassland species, knowledge regarding how they occur in relation to grazing intensity and soil nutrient availability is crucial. We focused on grassland plant species, i.e., species selected to indicate high natural values in semi-natural grasslands. Environmental monitoring data collected at 366 grassland sites in southern Sweden between 2006 and 2010 were used to relate the occurrence of indicator species to factors describing geographic location, local site conditions related to nutrients and moisture, and management. Site productivity, soil moisture and cover of trees and shrubs were the main structuring factors, while other factors related to management had a lesser effect (grass sward height, amount of litter, type of grazer). Not surprisingly, these patterns were also reflected in species-wise analyses of the 25 most commonly occurring indicator species, with almost all species negatively related to site productivity and most also to soil moisture. Furthermore, many species were negatively affected by increasing sward height and litter. In contrast, species-wise responses varied among species in relation to increasing cover of trees and shrubs. In comparison to cattle grazing, sheep grazing was detrimental to six species and beneficial to none, while horse grazing was detrimental to no species and beneficial to four species. When evaluating species traits, taller plant species were favoured when site productivity, grass sward height and the amount of grass litter were high. There were no strong patterns related to the flowering time, leaf arrangement, or nutrient and light requirements of species. These results highlight the importance of nutrient-poor and dry sites, e.g., when selecting sites for conservation, and the importance of the type of management executed.
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| 17. |
- Milberg, Per, et al.
(author)
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Using citizen science data to compare flight phenology of two oligolectic bees (Hymenoptera: Andrenidae) with the flowering of their host plants
- 2024
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In: European Journal of Entomology. - : CZECH ACAD SCI, INST ENTOMOLOGY. - 1210-5759 .- 1802-8829. ; 121, s. 67-72
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Journal article (peer-reviewed)abstract
- Understanding the relationship between solitary bee flight and flowering phenology is globally relevant for environmental management and habitat restoration. Using Swedish citizen science data over an 11 -year period, the fl ight behaviours of two oligolectic solitary bees (Andrena hattorfiana and Andrena marginata) were compared to the flowering phenology of their hosts (Knautia arvensis and Succisa pratensis) in southern Sweden. There were 2,327 and 4,566 records of fl ight and fl owering, respectively. While associative studies cannot resolve the degree of oligolecty, a strong temporal association of Andrena hattorfiana with Knautia arvensis and Andrena marginata with Succisa pratensis was indicated. Three conclusions emerged when comparing annual data: first, the flight period of both bee species studied overlapped with the flowering period of their corresponding host plants. Second, earlier fl owering of Knautia arvensis corresponded with the earlier fl ight of Andrena hattorfiana. Third, the fl ight period duration was unaffected by the flowering period duration. For Andrena hattorfiana/Knautia arvensis, climate change may shift the start of fl ight and fl owering periods to earlier dates in the year. A similar response would be expected for Andrena marginata/Knautia arvensis, but not for Andrena marginata/Succisa pratensis where there instead might be an increasing mismatch between the fl ight and fl owering periods.
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| 18. |
- Plue, Jan, et al.
(author)
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Buffering effects of soil seed banks on plant community composition in response to land use and climate
- 2020
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In: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 30:1, s. 128-139
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Journal article (peer-reviewed)abstract
- 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.Location Europe.Time period 1978–2014.Major taxa studied Flowering plantsMethodsUsing 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 temperature range more important than mean annual temperature for determining richness. Climate and land‐use effects were generally less pronounced when plant community richness included seed bank species richness, while there was no clear effect of land use and climate on compositional similarity between the seed bank and the herb layer.Main conclusionsHigh seed bank diversity and compositional similarity between the herb layer and seed bank plant communities may provide a potentially important functional buffer against the impact of ongoing environmental changes on plant communities. This capacity could, however, be threatened by climate warming. Dormant life‐history stages can therefore be important sources of diversity in changing environments, potentially underpinning already observed time‐lags in plant community responses to global change. However, as soil seed banks themselves appear, albeit less, vulnerable to the same changes, their potential to buffer change can only be temporary, and major community shifts may still be expected.
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| 19. |
- Plue, Jan, et al.
(author)
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European soil seed bank communities across a climate and land-cover gradient
- 2020
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Other publicationabstract
- This is the data set used for the publication Buffering effects of soil seed banks on plant community composition in response to land use and climate, published in the journal Global Ecology and Biogeography.Aim.Climate 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.Location. EuropeTime period. 1978 – 2014Major taxa studied. Flowering plantsMethods.Using a space-for-time/warming approach, we study plant species richness and composition in the herb layer and the soil seed bank in 2796 community plots from 54 datasets in managed grasslands, forests and intermediate, successional habitats across a climate gradient.Results.Soil 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 temperature range more important than mean annual temperature for determining richness. Climate and land use effects were generally less pronounced when plant community richness included seed bank species richness, while there was no clear effect of land use and climate on compositional similarity between the seed bank and the herb layer.Main conclusions.High seed bank diversity and compositional similarity between the herb layer and seed bank plant communities may provide a potentially important functional buffer against the impact of ongoing environmental changes on plant communities. This capacity could, however, be threatened by climate warming. Dormant life-history stages can therefore be important sources of diversity in changing environments, potentially underpinning already observed time-lags in plant community responses to global change. However, as soil seed banks themselves appear, albeit less, vulnerable to the same changes, their potential to buffer change can only be temporary, and major community shifts may still be expected.MethodsThis dataset is a collection of 41 published and 5 unpublished data sets, consisting of 2796 plots with corresponding seed bank and herb layer community data. Sampling effort varied across data sets, but involved sampling of the soil and subsequent germination trials in a greenhouse to determine seed bank composition. Herb layer communities were determined by the identification of plants in relevés. Please consult the readme file and published paper for further details.Usage NotesPlease contact database or individual data set authors for further information and collaboration when using the data set or any of its component parts. Please also note that some of these data sets have already been published alongside their orginal papers. Finally, please cite data and datasets according to community standards.
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| 20. |
- Westerberg, Lars, et al.
(author)
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Color pan traps often catch less when there are more flowers around
- 2021
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In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11:9, s. 3830-3840
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Journal article (peer-reviewed)abstract
- When assessing changes in populations of species, it is essential that the methods used to collect data have some level of precision and preferably also good accuracy. One commonly used method to collect pollinators is colour pan traps, but this method has been suggested to be biased by the abundance of surrounding flowers. The present study evaluated the relationship between pan trap catches and the frequency of flowers on small (25 m(2)) and large (2-6 ha) spatial scales. If pan traps work well, one should assume a positive relationship, that is, more insects caught when they have more food. However, in contrast, we found that catches in pan traps were often negatively affected by flower frequency. Among the six taxa evaluated, the negative bias was largest in Vespoidea and Lepturinae, while there was no bias in solitary Apoidea (Cetoniidae, Syrphidae and social Apoidea were intermediate). Furthermore, red flowers seemed to contribute most to the negative bias. There was also a tendency that the negative bias differed within the flight season and that it was higher when considering the large spatial scale compared to the small one. To conclude, pan trap catches may suffer from a negative bias due to surrounding flower frequency and color. The occurrence and magnitude of the negative bias were context and taxon dependent, and therefore difficult to adjust for. Thus, pan traps seem less suited to evaluate differences between sites and the effect of restoration, when gradients in flower density are large. Instead, it seems better suited to monitor population changes within sites, and when gradients are small.
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