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Jonsson, Bengt-Gunnar
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Publications (10 of 127) Show all publications
Ekström, M., Esseen, P.-A. -., Westerlund, B., Grafström, A., Jonsson, B.-G. & Ståhl, G. (2018). Logistic regression for clustered data from environmental monitoring programs. Ecological Informatics, 43, 165-173
Open this publication in new window or tab >>Logistic regression for clustered data from environmental monitoring programs
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2018 (English)In: Ecological Informatics, ISSN 1574-9541, E-ISSN 1878-0512, Vol. 43, p. 165-173Article in journal (Refereed) Published
Abstract [en]

Large-scale surveys, such as national forest inventories and vegetation monitoring programs, usually have complex sampling designs that include geographical stratification and units organized in clusters. When models are developed using data from such programs, a key question is whether or not to utilize design information when analyzing the relationship between a response variable and a set of covariates. Standard statistical regression methods often fail to account for complex sampling designs, which may lead to severely biased estimators of model coefficients. Furthermore, ignoring that data are spatially correlated within clusters may underestimate the standard errors of regression coefficient estimates, with a risk for drawing wrong conclusions. We first review general approaches that account for complex sampling designs, e.g. methods using probability weighting, and stress the need to explore the effects of the sampling design when applying logistic regression models. We then use Monte Carlo simulation to compare the performance of the standard logistic regression model with two approaches to model correlated binary responses, i.e. cluster-specific and population-averaged logistic regression models. As an example, we analyze the occurrence of epiphytic hair lichens in the genus Bryoria; an indicator of forest ecosystem integrity. Based on data from the National Forest Inventory (NFI) for the period 1993–2014 we generated a data set on hair lichen occurrence on >100,000 Picea abies trees distributed throughout Sweden. The NFI data included ten covariates representing forest structure and climate variables potentially affecting lichen occurrence. Our analyses show the importance of taking complex sampling designs and correlated binary responses into account in logistic regression modeling to avoid the risk of obtaining notably biased parameter estimators and standard errors, and erroneous interpretations about factors affecting e.g. hair lichen occurrence. We recommend comparisons of unweighted and weighted logistic regression analyses as an essential step in development of models based on data from large-scale surveys. 

Keywords
Bryoria, Cluster-specific model, Complex sampling design, Correlated data, Logistic regression, National forest inventory, Population-averaged model
National Category
Biological Sciences
Identifiers
urn:nbn:se:miun:diva-32718 (URN)10.1016/j.ecoinf.2017.10.006 (DOI)000424721000015 ()2-s2.0-85038109792 (Scopus ID)
Available from: 2018-01-19 Created: 2018-01-19 Last updated: 2018-03-19Bibliographically approved
Bernes, C., Macura, B., Jonsson, B.-G., Junninen, K., Müller, J., Sandström, J., . . . Macdonald, E. (2018). Manipulating ungulate herbivory in temperate and boreal forests: Effects on vegetation and invertebrates. A systematic review. Environmental Evidence, 7(1), Article ID 13.
Open this publication in new window or tab >>Manipulating ungulate herbivory in temperate and boreal forests: Effects on vegetation and invertebrates. A systematic review
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2018 (English)In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 7, no 1, article id 13Article, review/survey (Refereed) Published
Abstract [en]

Background: Livestock grazing and 'overabundance' of large wild herbivores in forested areas have long been perceived as conflicting with the aims of both silviculture and forest conservation; however, certain kinds of herbivory can help to maintain habitat values in forest ecosystems. Management of mammalian herbivory in protected forests can, therefore, be a critical tool for biodiversity conservation. The primary aim of this systematic review was to examine how forest vegetation and invertebrates are affected by manipulation of the grazing/browsing pressure by livestock or wild ungulates. The ultimate purpose was to investigate whether such manipulation is useful for conserving or restoring biodiversity in forest set-asides. Methods: We considered studies of manipulated ungulate herbivory in forests anywhere within the boreal and temperate zones, not only in protected areas but also in production forest. Non-intervention or alternative levels of intervention were used as comparators. Relevant outcomes included abundance, diversity and composition of plants and invertebrates, tree regeneration, and performance of focal/target species. Studies were mainly selected from a recent systematic map of the evidence on biodiversity effects of forest management relevant to protected areas. Additional studies were identified through updated searches online and in bibliographies of existing reviews. Relevant studies were critically appraised, and studies with low or unclear validity were excluded from the review. Quantitative outcomes were extracted from 103 articles, and summary effect sizes were derived by meta-analysis. Results: Most of the 144 studies included in the review had been conducted in North America, Europe or Australia/New Zealand. The intervention most commonly studied was experimental exclusion (or enclosure) of wild and/or domestic ungulates by fencing. Other studies examined culling of wild ungulates or compared forests long grazed by livestock to ungrazed forests. Effects on vegetation and invertebrates were reported in 135 and 23 of the studies, respectively. We found negative responses to herbivory in the abundance of understorey vegetation as a whole, woody understorey and bryophytes, and also in the species richness of woody understorey vegetation, whereas the richness of forbs and bryophytes responded positively. Several effects depended on ungulate origins: Understorey abundance responded negatively to livestock and to ungulates introduced into the wild, but not to native ones. In contrast, understorey species richness responded positively to livestock but not to wild ungulates. The duration and intensity of herbivory had few significant effects on vegetation - exceptions included woody understorey abundance and richness, which decreased with increasing duration and intensity, respectively. Among invertebrates we found negative responses to herbivory in the abundance of lepidopterans and spiders, but no significant effects on species richness. Conclusions: Our review revealed a large body of high-validity experimental studies on impacts of ungulate herbivory in forests. This evidence confirmed that manipulation of such herbivory is often highly influential on tree regeneration and on the abundance, diversity and composition of understorey vegetation. Nevertheless, we also identified important knowledge gaps - we found few studies of boreal areas, long-term herbivory effects, impacts on bryophytes, lichens and invertebrates, and effects of manipulation less radical than total exclusion of ungulates. 

Keywords
Biodiversity, Deer, Forest conservation, Forest restoration, Forest set-aside, Herbivory, Livestock, Natural regeneration, Silvopastoral system, Wood-pasture
National Category
Biological Sciences
Identifiers
urn:nbn:se:miun:diva-33695 (URN)10.1186/s13750-018-0125-3 (DOI)2-s2.0-85046121337 (Scopus ID)
Available from: 2018-06-01 Created: 2018-06-01 Last updated: 2018-06-01Bibliographically approved
Ruete, A., Snäll, T., Jonsson, B.-G. & Jönsson, M. (2017). Contrasting long-term effects of transient anthropogenic edges and forest fragment size on generalist and specialist deadwood-dwelling fungi. Journal of Applied Ecology, 54(4), 1142-1151
Open this publication in new window or tab >>Contrasting long-term effects of transient anthropogenic edges and forest fragment size on generalist and specialist deadwood-dwelling fungi
2017 (English)In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 54, no 4, p. 1142-1151Article in journal (Refereed) Published
Abstract [en]

Forests are becoming increasingly fragmented world-wide, creating forest patches with reduced area and greater exposure to human land uses along fragment edges. In this study, we predict the future impacts of anthropogenic edges and fragment size on the future occupancy of deadwood-dwelling fungi in boreal old-growth forest fragments. We used Bayesian models fitted to empirical data to predict 40years of occupancy dynamics of logs by a group of old-growth forest indicator fungi and two common fungi under different scenarios of clear-cutting in adjacent forest (0%, 25%, 50% and 100%) and fragment sizes (1-20ha). Small fragment size (1-3<bold></bold>14ha) and intensified forestry with 50-100% clear-cutting of forest around old-growth forest fragments lead to lower predicted occupancy of old-growth indicator fungi while common generalist species like Fomitopsis pinicola increased. There was a trade-off between fragment size and management, where increasing fragment size buffered the negative long-term effects from increased adjacent clear-cutting. These changes in fungal occupancy at the edge should be accounted for when working towards conservation targets for protected areas, such as the Aichi target 11.Synthesis and applications. Preserve what is left - but buffer for change. Small forest fragments often represent the last vestiges of high habitat quality (i.e. species, structures) in managed forest landscapes. As effective area-based conservation measures for the long-term occupancy of old-growth fungi, small fragments need to be managed to protect species from degrading transient edge effects. Management should focus on increasing the size of conservation areas with permanent buffer zones. Alternatively, non-simultaneous adjacent clear-cutting in a way that reduces the edge effect over time (i.e. dynamic buffers) may increase the effective area and improve performance of set-asides in protecting species of special concern for conservation. Preserve what is left - but buffer for change. Small forest fragments often represent the last vestiges of high habitat quality (i.e. species, structures) in managed forest landscapes. As effective area-based conservation measures for the long-term occupancy of old-growth fungi, small fragments need to be managed to protect species from degrading transient edge effects. Management should focus on increasing the size of conservation areas with permanent buffer zones. Alternatively, non-simultaneous adjacent clear-cutting in a way that reduces the edge effect over time (i.e. dynamic buffers) may increase the effective area and improve performance of set-asides in protecting species of special concern for conservation.

Keywords
boreal forests, common and indicator species, core:edge ratio, deadwood, edge effect, fragment size, projection scenarios, protected areas, set-asides
National Category
Ecology
Identifiers
urn:nbn:se:miun:diva-31364 (URN)10.1111/1365-2664.12835 (DOI)000405534500014 ()2-s2.0-85023643280 (Scopus ID)
Available from: 2017-08-10 Created: 2017-08-10 Last updated: 2017-12-18Bibliographically approved
Carlsson, F., Edman, M. & Jonsson, B.-G. (2017). Increased CO2 evolution caused by heat treatment in wood-decaying fungi. Mycological progress, 16(5), 513-519
Open this publication in new window or tab >>Increased CO2 evolution caused by heat treatment in wood-decaying fungi
2017 (English)In: Mycological progress, ISSN 1617-416X, E-ISSN 1861-8952, Vol. 16, no 5, p. 513-519Article in journal (Refereed) Published
Abstract [en]

Wood-decaying fungi are regarded as the main decomposers of woody debris in boreal forests. Given that fungal respiration makes a significant contribution to terrestrial carbon flows, it is important to understand how the wood-decaying fungal metabolism is regulated in relation to different environmental conditions and disturbances. In the present study, we investigated the effect of temperature stress on wood decomposition rate in 18 species of wood-decaying fungi, representing a broad range of species-habitat associations. Heat shock duration and temperature were calibrated to match the conditions of a forest fire. We found a general increase in fungal decay rate after heat shock; the response was more pronounced in species associated with fire-prone forests. The underlying mechanism is unclear, but possibly relates to an up-regulation at the cellular level in response to heat shock. Our results show that the decomposition rate of dead wood can be strongly affected by environmental triggers.

Keywords
Decomposition, Saproxylic fungi, CO2, Heat treatment, Wood decay, Carbon cycling
National Category
Biological Sciences
Identifiers
urn:nbn:se:miun:diva-30835 (URN)10.1007/s11557-017-1281-5 (DOI)000399824400004 ()2-s2.0-85014052521 (Scopus ID)
Available from: 2017-06-09 Created: 2017-06-09 Last updated: 2017-12-18Bibliographically approved
Ståhl, G., Ekström, M., Dahlgren, J., Esseen, P.-A., Grafström, A. & Jonsson, B.-G. (2017). Informative plot sizes in presence-absence sampling of forest floor vegetation. Methods in Ecology and Evolution, 8(10), 1284-1291
Open this publication in new window or tab >>Informative plot sizes in presence-absence sampling of forest floor vegetation
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2017 (English)In: Methods in Ecology and Evolution, ISSN 2041-210X, E-ISSN 2041-210X, Vol. 8, no 10, p. 1284-1291Article in journal (Refereed) Published
Abstract [en]

Plant communities are attracting increased interest in connection with forest and landscape inventories due to society's interest in ecosystem services. However, the acquisition of accurate information about plant communities poses several methodological challenges. Here, we investigate the use of presence-absence sampling with the aim to monitor state and change in plant density. We study what plot sizes are informative, i.e. the estimators should have as high precision as possible. Plant occurrences were modelled through different Poisson processes and tests were developed for assessing the plausibility of the model assumptions. Optimum plot sizes were determined by minimizing the variance of the estimators. While state estimators of similar kind as ours have been proposed in previous studies, our tests and change estimation procedures are new. We found that the most informative plot size for state estimation is 1·6 divided by the plant density, i.e. if the true density is 1 plant per square metre the optimum plot size is 1·6 square metres. This is in accordance with previous findings. More importantly, the most informative plot size for change estimation was smaller and depended on the change patterns. We provide theoretical results as well as some empirical results based on data from the Swedish National Forest Inventory. Use of too small or too large plots resulted in poor precision of the density (and density change) estimators. As a consequence, a range of different plot sizes would be required for jointly monitoring both common and rare plants using presence-absence sampling in monitoring programmes. 

Keywords
density, intensity, optimum plot size, plant monitoring, point pattern, Poisson model, sample plots, vegetation change, vegetation survey
National Category
Ecology
Identifiers
urn:nbn:se:miun:diva-32220 (URN)10.1111/2041-210X.12749 (DOI)000412858600012 ()2-s2.0-85031105755 (Scopus ID)
Available from: 2017-12-04 Created: 2017-12-04 Last updated: 2017-12-12Bibliographically approved
Jonsson, B.-G. (2017). Inget nytt under solen: 200 ord med Malthus. In: Edith Andresen, Gustav Lidén, Sara Nyhlén (Ed.), Hållbarhetens många ansikten: samtal, forskning och fantasier (pp. 139-139). Sundsvall: Mid Sweden University
Open this publication in new window or tab >>Inget nytt under solen: 200 ord med Malthus
2017 (Swedish)In: Hållbarhetens många ansikten: samtal, forskning och fantasier / [ed] Edith Andresen, Gustav Lidén, Sara Nyhlén, Sundsvall: Mid Sweden University , 2017, p. 139-139Chapter in book (Other academic)
Place, publisher, year, edition, pages
Sundsvall: Mid Sweden University, 2017
Series
Genusstudier vid Mittuniversitetet, ISSN 1654-5753 ; 13
National Category
Ecology
Identifiers
urn:nbn:se:miun:diva-32386 (URN)978-91-88527-37-0 (ISBN)
Available from: 2017-12-11 Created: 2017-12-11 Last updated: 2017-12-11
Kuuluvainen, T., Hofgaard, A., Aakala, T. & Jonsson, B. G. (2017). North Fennoscandian mountain forests: History, composition, disturbance dynamics and the unpredictable future. Forest Ecology and Management, 385, 140-149
Open this publication in new window or tab >>North Fennoscandian mountain forests: History, composition, disturbance dynamics and the unpredictable future
2017 (English)In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 385, p. 140-149Article in journal (Refereed) Published
Abstract [en]

North Fennoscandian mountain forests are distributed along the Scandes Mountains between Sweden and Norway, and the low-mountain regions of northern Norway, Sweden and Finland, and the adjacent northwestern Russia. Regionally, these forests are differentiated into spruce, pine or birch dominance due to climatic differences. Variation in tree species dominance within these regions is generally caused by a combination of historical and prevailing disturbance regimes, including both chronic and episodic disturbances, their magnitude and frequency, as well as differences in edaphic conditions and topography. Because of their remoteness, slow growth and restrictions of use, these mountain forests are generally less affected by human utilization than more productive and easily utilizable forests at lower elevations and/or latitudes. As a consequence, these northern forests of Europe are often referred to as “Europe's last wilderness”, even if human influence of varying intensity has been ubiquitous through historical time. Because of their naturalness, the North Fennoscandian mountain forests are of paramount importance for biodiversity conservation, monitoring of ecosystem change and for their sociocultural values. As such, they also provide unique reference areas for basic and applied research, and for developing methods of forest conservation, restoration and ecosystem-based management for the entire Fennoscandia. However, the current rapid change in climate is predicted to profoundly affect the ecology and dynamics of these forests in the future.

Keywords
Biodiversity, Boreal forest, Climate change, Cultural heritage, Natural disturbance, Northern Europe
National Category
Biological Sciences
Identifiers
urn:nbn:se:miun:diva-29813 (URN)10.1016/j.foreco.2016.11.031 (DOI)000392680800015 ()2-s2.0-85028259263 (Scopus ID)
Note

Reprint of: North Fennoscandian mountain forests: History, composition, disturbance dynamics and the unpredictable future

Part of the special issue: “Ecology of Mountain Forest Ecosystems in Europe” published in the journal Forest Ecology and Management 388, 2017.

https://doi.org/10.1016/j.foreco.2017.02.035

WOS: 000399521200009

Available from: 2017-01-02 Created: 2017-01-02 Last updated: 2017-11-30Bibliographically approved
Esseen, P.-A. -., Ekström, M., Westerlund, B., Palmqvist, K., Jonsson, B. G., Grafström, A. & Ståhl, G. (2016). Broad-scale distribution of epiphytic hair lichens correlates more with climate and nitrogen deposition than with forest structure. Canadian Journal of Forest Research, 46(11), 1348-1358
Open this publication in new window or tab >>Broad-scale distribution of epiphytic hair lichens correlates more with climate and nitrogen deposition than with forest structure
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2016 (English)In: Canadian Journal of Forest Research, ISSN 0045-5067, E-ISSN 1208-6037, Vol. 46, no 11, p. 1348-1358Article in journal (Refereed) Published
Abstract [en]

Hair lichens are strongly influenced by forest structure at local scales, but their broad-scale distributions are less understood. We compared the occurrence and length of Alectoria sarmentosa (Ach.) Ach., Bryoria spp., and Usnea spp. in the lower canopy of &gt; 5000 Picea abies (L.) Karst. trees within the National Forest Inventory across all productive forest in Sweden. We used logistic regression to analyse how climate, nitrogen deposition, and forest variables influence lichen occurrence. Distributions overlapped, but the distribution of Bryoria was more northern and that of Usnea was more southern, with Alectoria's distribution being intermediate. Lichen length increased towards northern regions, indicating better conditions for biomass accumulation. Logistic regression models had the highest pseudo R2 value for Bryoria, followed by Alectoria. Temperature and nitrogen deposition had higher explanatory power than precipitation and forest variables. Multiple logistic regressions suggest that lichen genera respond differently to increases in several variables. Warmingdecreased the odds for Bryoria occurrence at all temperatures. Corresponding odds for Alectoria and Usnea decreased in warmer climates, but in colder climates, they increased. Nitrogen addition decreased the odds for Alectoria and Usnea occurrence under high deposition, but under low deposition, the odds increased. Our analyses suggest major shifts in the broad-scale distribution of hair lichens with changes in climate, nitrogen deposition, and forest management.

Keywords
Climate change, Epiphytic lichens, Forest structure, Nitrogen deposition, Temperature
National Category
Biological Sciences
Identifiers
urn:nbn:se:miun:diva-29297 (URN)10.1139/cjfr-2016-0113 (DOI)000386675600012 ()2-s2.0-84992362214 (Scopus ID)
Note

Dubbelt WoS-nummer: 000393108100012

Available from: 2016-11-14 Created: 2016-11-14 Last updated: 2017-08-09Bibliographically approved
Jonsson, B.-G., Ekström, M., Esseen, P.-A., Grafström, A., Ståhl, G. & Westerlund, B. (2016). Dead wood availability in managed Swedish forests - Policy outcomes and implications for biodiversity. Forest Ecology and Management, 376, 174-182
Open this publication in new window or tab >>Dead wood availability in managed Swedish forests - Policy outcomes and implications for biodiversity
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2016 (English)In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 376, p. 174-182Article in journal (Refereed) Published
Abstract [en]

Dead wood is a critical resource for forest biodiversity and widely used as an indicator for sustainable forest management. Based on data from the Swedish National Forest Inventory we provide baseline information and analyze trends in volume and distribution of dead wood in Swedish managed forests during 15 years. The data are based on ≈30,000 sample plots inventoried during three periods (1994-1998; 2003-2007 and 2008-2012). The forest policy has since 1994 emphasized the need to increase the amount of dead wood in Swedish forests. The average volume of dead wood in Sweden has increased by 25% (from 6.1 to 7.6 m3 ha-1) since the mid-1990s, but patterns differed among regions and tree species. The volume of conifer dead wood (mainly from Picea abies) has increased in the southern part of the country, but remained stable or decreased in the northern part. Heterogeneity of dead wood types was low in terms of species, diameter and decay classes, potentially negatively impacting on biodiversity. Overall, we found only minor effects of the current forest policy since most of the increase can be attributed to storm events creating a pulse of hard dead wood. Therefore, the implementation of established policy instruments (e.g. legislation and voluntary certification schemes) need to be revisited. In addition to the retention of dead trees during forestry operations, policy makers should consider calling for more large-scale targeted creation of dead trees and management methods with longer rotation cycles. © 2016 The Authors.

Keywords
Boreal forest, Environmental objectives, National Forest Inventory, Natura 2000, Saproxylic species, Western Taiga
National Category
Biological Sciences
Identifiers
urn:nbn:se:miun:diva-28489 (URN)10.1016/j.foreco.2016.06.017 (DOI)000381233500018 ()2-s2.0-84974578053 (Scopus ID)
Funder
Swedish Research Council, 340-2013-5076
Note

CODEN: FECMD

Available from: 2016-07-22 Created: 2016-07-21 Last updated: 2017-08-09Bibliographically approved
Hedenström, E., Fagerlund-Edfeldt, A., Edman, M. & Jonsson, B.-G. (2016). Resveratrol, piceatannol, and isorhapontigenin from Norway spruce (Picea abies) debarking wastewater as inhibitors on the growth of nine species of wood-decaying fungi. Wood Science and Technology, 50(3), 617-629
Open this publication in new window or tab >>Resveratrol, piceatannol, and isorhapontigenin from Norway spruce (Picea abies) debarking wastewater as inhibitors on the growth of nine species of wood-decaying fungi
2016 (English)In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 50, no 3, p. 617-629Article in journal (Refereed) Published
Abstract [en]

The diethyl ether extract obtained from solvent-solvent extraction of Norway spruce (Picea abies) debarking water, a byproduct from debarking of logs in the pulp and paper industry, was tested for inhibition of growth on agar plates of nine species of wood-decaying fungi: Antrodia sinuosa, Antrodia xantha, Coniophora puteana, Fomitopsis pinicola, Gloeophyllum sepiarium, Heterobasidion parviporum, Phlebiopsis gigantea, Serpula himantioides, and Serpula lacrymans. One fraction of the extract showed excellent antifungal activity for a majority of the species, with complete inhibition of growth for A. sinuosa, A. xantha, and G. sepiarium. The major constituents of the most active fraction were identified as the hydroxystilbenes resveratrol, isorhapontigenin (synonymous with methyl piceatannol), and piceatannol (synonymous with astringenin). The active compounds were isolated or synthesized and used individually for dose-response studies. It was found that isorhapontigenin and piceatannol inhibited all growth of A. sinuosa, A. xantha, and G. sepiarium in 0.35 % weight concentration. The hydroxystilbenes were the three most abundant substances in the debarking water and can be obtained as a mixture or in enriched forms. From some extraction steps of the raw debarking water, it would be possible to obtain the hydroxystilbenes in quantities that might be of commercial interest as efficient natural fungicides.

National Category
Ecology
Identifiers
urn:nbn:se:miun:diva-27810 (URN)10.1007/s00226-016-0814-4 (DOI)000373743300012 ()2-s2.0-84961825289 (Scopus ID)
Available from: 2016-06-08 Created: 2016-06-07 Last updated: 2017-11-30Bibliographically approved
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