Jan-olov Weslien - Academia.edu (original) (raw)
Papers by Jan-olov Weslien
Canadian Journal of Forest Research, 1990
The Canadian Entomologist
ABSTRACT
Forest Ecology and Management
Det är ingen större risk för insektsskador på omgivande granskog vid lagring av skogsbränsle. Det... more Det är ingen större risk för insektsskador på omgivande granskog vid lagring av skogsbränsle. Det är en slutsats som kan dras av en studie i Uppland och södra Dalarna. Under tre somrar placerades högar av fällda unggranar i kanten mellan hygge och granungskog på 31 försöks- platser. På samtliga platser blev det angrepp av sex- tandad barkborre på omgivande skog,
Agricultural and Forest Entomology, 2014
ABSTRACT
Insect Conservation and Diversity, 2015
1. Life history traits of solitary nest provisioning bees and wasps (Aculeata) are characterised ... more 1. Life history traits of solitary nest provisioning bees and wasps (Aculeata) are characterised by low fecundity and extensive parental care. Therefore, it can be expected that egg-laying females are demanding in their nest choice.
Journal of economic entomology, 2004
We investigated the effects of Bacillus thuringiensis variety kurstaki x aizawai (Bt) on infestat... more We investigated the effects of Bacillus thuringiensis variety kurstaki x aizawai (Bt) on infestation levels of two lepidopteran insects as well as on seed quality in Norway spruce, Picea abies L. (Karst.) in central Sweden. Spruce flowers (female strobili) were sprayed with a 0.2% suspension (wt:wt) of the Bt preparation Turex 50 WP, 25,000 IU/mg in water. To expose even those lepidopteran larvae that feed exclusively embedded within the cone tissue, the Bt treatment was applied to open flowers, before they closed and developed into cones. The experimental design included three main factors: treatment (untreated control, water, or Bt), spruce genotype (three clones), and spraying time (spraying before, during, and after the phase of highest pollen receptivity). The Bt treatment reduced the proportion of cones infested by the cone worm Dioryctria abietella Den. et Schiff. (Lepidoptera: Pyralidae) from approximately 30 to 15%. There was no statistically significant treatment effect on...
Systematics and Biodiversity, 2010
Scandinavian Journal of Forest Research, 2009
Forest productivity is expected to increase in the future owing to the use of genetically improve... more Forest productivity is expected to increase in the future owing to the use of genetically improved plant material and climate warming. Increased productivity will lead to shorter optimum rotation lengths and larger annual clear-cut areas. This study explored the likely effects of ...
Scandinavian Journal of Forest Research, 2005
ABSTRACT Damage by the large pine weevil, Hylobius abietis (L.), is a major threat to conifer pla... more ABSTRACT Damage by the large pine weevil, Hylobius abietis (L.), is a major threat to conifer plantations throughout Eurasia, but damage is usually less severe in northern areas. However, pine weevil damage seems to increase if the sites are burnt. The aim of this study was to determine the effects of variations in the time of planting (with respect to the total age of the clear-cut and the time since burning) on pine weevil damage to seedlings on burnt sites in northern Sweden. The study also explored whether there is an optimal time for planting at which damage levels are reduced to acceptable levels. Ten sites were selected in an inland area of northern Sweden where pine weevils are normally scarce. The sites were dry–mesic and represented a range of times since clear-cutting and since burning. The sites were planted in June 1998, 1999 and 2000 with 1-year-old container-grown seedlings of Norway spruce [Picea abies (L.) Karst.]. Pine weevil damage was reduced if planting was done no earlier than 3 years after clear-cutting and no earlier than 2 years after burning. Planting too soon after burning, irrespective of the age of the clear-cut, resulted in unacceptably high damage levels.
Scandinavian Journal of Forest Research, 1989
The risk for damage associated with spruce bark beetle attacks on living trees was estimated in 1... more The risk for damage associated with spruce bark beetle attacks on living trees was estimated in 12 forest districts in the Nordic countries during three years. Pheromone‐baited traps and trees were used. Five groups of three traps were deployed annually on fresh spruce clear‐ ...
Journal of Economic Entomology, 2004
ABSTRACT
Journal of Chemical Ecology, 1987
In field experiments in Sweden, the constituent 2-methyl-3-buten-2-ol of the aggregation pheromon... more In field experiments in Sweden, the constituent 2-methyl-3-buten-2-ol of the aggregation pheromone of the spruce bark bettleIps typographus (L.) was effectively replaced by 2-methyl-3-butyn-2-ol.
Journal of Applied Entomology, 2011
ABSTRACT
Journal of Applied Entomology, 1988
ABSTRACT
Journal of Animal Ecology, 2011
1. Priority effects have been hypothesized to have long-lasting impact on community structure in ... more 1. Priority effects have been hypothesized to have long-lasting impact on community structure in natural ecosystems. Long-term studies of priority effects in natural ecosystems are however sparse, especially in terrestrial ecosystems. 2. Wood decay is a slow process involving a high diversity of insect and fungus species. Species interactions that drive change in communities of insects and fungi during wood decay are poorly understood because of a lack of sufficient long-term studies. 3. In this paper, we followed the colonization and succession of wood-living insects and fungi on cut trees during 15 years, from tree death and onwards, in a boreal forest landscape. We test the long-term priority effects hypothesis that the identity and abundance of species that colonize first affect the colonization success of later-arriving species. We also hypothesize that species interact in both facilitative and inhibitory ways, which ultimately affect habitat quality for a red-listed late-succession beetle species. 4. Possible causal associations between species were explored by path analysis. The results indicate that one bark beetle species, Hylurgops palliatus, and one wood-borer species, Monochamus sutor, which colonized the wood during the first year after cutting, influenced the occurrence of a rare, wood-living beetle, Peltis grossa, that started to emerge from the stumps about 10 years later. The positive effects of Hylurgops palliatus and negative effects of M. sutor were largely mediated through the wood-decaying fungus species Fomitopsis pinicola. 5. The study shows that variable priority effects may have long-lasting impact on community assembly in decaying wood. The study also exemplifies new possibilities for managing populations of threatened species by exploring links between early, well-understood species guilds and late, more poorly understood species guilds.
Forest Ecology and Management, 2008
The availability of habitat for wood-dependent species has been greatly reduced in Fennoscandian ... more The availability of habitat for wood-dependent species has been greatly reduced in Fennoscandian boreal forests and hence the setting aside of forest land for conservation purposes is a common strategy. Here, we explore the biodiversity quality and conservation relevance of three categories of set-asides dominated by Norway spruce (nature reserves, woodland key habitats and retention patches, i.e. groups of living
Forest Ecology and Management, 1999
Relative population levels of the spruce bark beetle, Ips typographus (L.) (Coleoptera, Scolytida... more Relative population levels of the spruce bark beetle, Ips typographus (L.) (Coleoptera, Scolytidae) and associated insects were estimated in 12 spruce stands in central Sweden. Spruce bolts and window traps baited with semiochemicals were used for the monitoring. Six stands were unmanaged and had ongoing attacks on standing trees by I. typographus. This had led to an accumulation of dead spruce trees during several years. These six stands were compared pairwise with six old-managed stands with similar forest structure, but with no attacks during the previous years and with low amounts of dead trees. Catches of 17 species were included in a quantitative analysis. Four species, all known to be common predators in I. typographus galleries, were caught in signi®cantly higher numbers in the unmanaged stands (two-to three-fold difference). In contrast, the number of I. typographus caught was almost identical for the two stand types. Our results indicate that predators of the spruce bark beetle may be more sensitive to certain forestry operations than their prey. Caging or baiting of bolts strongly in¯uenced the colonization of predatory species and the number of I. typographus offspring that emerged. Compared to uncaged, unbaited bolts, offspring production was ca. 30% higher in bolts caged with a ®ne nylon netting and ca. 30% lower in uncaged bolts baited with ethanol and -pinene. No difference between stand types was found in the production of offspring by I. typographus in the bolts. In a multiple-regression analysis, including the density of certain predators and of I. typographus galleries, one factor, namely`Thanasimus larvae per bolt', could signi®cantly explain some of the variation in I. typographus offspring production in the 36 bolts. #
Forest Ecology and Management, 2009
Forest Ecology and Management, 1999
Attacks of bark-and wood-boring beetles on mechanically created high stumps of Norway spruce, Pic... more Attacks of bark-and wood-boring beetles on mechanically created high stumps of Norway spruce, Picea abies L. (Karst.), were studied in the provinces of Dalarna (Granga Èrde area) and Uppland (Fagero Èn) in central Sweden. The experiment included a total of 362 stumps in the Granga Èrde area as well as 48 stumps and 18 logs at Fagero Èn. Most inspections were conducted in the ®rst and second autumns following the cuttings made to create the stumps. All stumps were attacked by at least one species during the two-year period, and for almost all of them (95%) the initial attacks occurred in the ®rst summer. The most frequently encountered species on the stumps were the scolytids Ips typographus (L.), Pityogenes chalcographus (L.), Hylurgops palliatus (Gyll.), Orthotomicus spp., Trypodendron lineatum (Oliv.), Dryocoetes sp. and Polygraphus poligraphus (L.), and the cerambycids Tetropium spp. and Monochamus sutor (L.). Both the time of cutting and stump diameter in¯uenced beetle colonisation. I. typographus was not found in autumn-cut stumps, while Orthotomicus spp. was found more frequently in autumn-cut stumps than in spring-cut stumps. There was a positive relationship between I. typographus occupancy and stump diameter, while negative relationships were found between stump diameter and H. palliatus and T. lineatum occupancy. Most stumps (ca. 80%) were attacked by more than one bark-and wood-boring species in the ®rst summer. The proportion of stumps attacked was signi®cantly higher than the proportion of logs attacked for P. poligraphus, T. lineatum and Tetropium spp., whereas the opposite was true for I. typographus. The percentage of bark area utilised by I. typographus was signi®cantly higher in logs than in stumps. #
Canadian Journal of Forest Research, 1990
The Canadian Entomologist
ABSTRACT
Forest Ecology and Management
Det är ingen större risk för insektsskador på omgivande granskog vid lagring av skogsbränsle. Det... more Det är ingen större risk för insektsskador på omgivande granskog vid lagring av skogsbränsle. Det är en slutsats som kan dras av en studie i Uppland och södra Dalarna. Under tre somrar placerades högar av fällda unggranar i kanten mellan hygge och granungskog på 31 försöks- platser. På samtliga platser blev det angrepp av sex- tandad barkborre på omgivande skog,
Agricultural and Forest Entomology, 2014
ABSTRACT
Insect Conservation and Diversity, 2015
1. Life history traits of solitary nest provisioning bees and wasps (Aculeata) are characterised ... more 1. Life history traits of solitary nest provisioning bees and wasps (Aculeata) are characterised by low fecundity and extensive parental care. Therefore, it can be expected that egg-laying females are demanding in their nest choice.
Journal of economic entomology, 2004
We investigated the effects of Bacillus thuringiensis variety kurstaki x aizawai (Bt) on infestat... more We investigated the effects of Bacillus thuringiensis variety kurstaki x aizawai (Bt) on infestation levels of two lepidopteran insects as well as on seed quality in Norway spruce, Picea abies L. (Karst.) in central Sweden. Spruce flowers (female strobili) were sprayed with a 0.2% suspension (wt:wt) of the Bt preparation Turex 50 WP, 25,000 IU/mg in water. To expose even those lepidopteran larvae that feed exclusively embedded within the cone tissue, the Bt treatment was applied to open flowers, before they closed and developed into cones. The experimental design included three main factors: treatment (untreated control, water, or Bt), spruce genotype (three clones), and spraying time (spraying before, during, and after the phase of highest pollen receptivity). The Bt treatment reduced the proportion of cones infested by the cone worm Dioryctria abietella Den. et Schiff. (Lepidoptera: Pyralidae) from approximately 30 to 15%. There was no statistically significant treatment effect on...
Systematics and Biodiversity, 2010
Scandinavian Journal of Forest Research, 2009
Forest productivity is expected to increase in the future owing to the use of genetically improve... more Forest productivity is expected to increase in the future owing to the use of genetically improved plant material and climate warming. Increased productivity will lead to shorter optimum rotation lengths and larger annual clear-cut areas. This study explored the likely effects of ...
Scandinavian Journal of Forest Research, 2005
ABSTRACT Damage by the large pine weevil, Hylobius abietis (L.), is a major threat to conifer pla... more ABSTRACT Damage by the large pine weevil, Hylobius abietis (L.), is a major threat to conifer plantations throughout Eurasia, but damage is usually less severe in northern areas. However, pine weevil damage seems to increase if the sites are burnt. The aim of this study was to determine the effects of variations in the time of planting (with respect to the total age of the clear-cut and the time since burning) on pine weevil damage to seedlings on burnt sites in northern Sweden. The study also explored whether there is an optimal time for planting at which damage levels are reduced to acceptable levels. Ten sites were selected in an inland area of northern Sweden where pine weevils are normally scarce. The sites were dry–mesic and represented a range of times since clear-cutting and since burning. The sites were planted in June 1998, 1999 and 2000 with 1-year-old container-grown seedlings of Norway spruce [Picea abies (L.) Karst.]. Pine weevil damage was reduced if planting was done no earlier than 3 years after clear-cutting and no earlier than 2 years after burning. Planting too soon after burning, irrespective of the age of the clear-cut, resulted in unacceptably high damage levels.
Scandinavian Journal of Forest Research, 1989
The risk for damage associated with spruce bark beetle attacks on living trees was estimated in 1... more The risk for damage associated with spruce bark beetle attacks on living trees was estimated in 12 forest districts in the Nordic countries during three years. Pheromone‐baited traps and trees were used. Five groups of three traps were deployed annually on fresh spruce clear‐ ...
Journal of Economic Entomology, 2004
ABSTRACT
Journal of Chemical Ecology, 1987
In field experiments in Sweden, the constituent 2-methyl-3-buten-2-ol of the aggregation pheromon... more In field experiments in Sweden, the constituent 2-methyl-3-buten-2-ol of the aggregation pheromone of the spruce bark bettleIps typographus (L.) was effectively replaced by 2-methyl-3-butyn-2-ol.
Journal of Applied Entomology, 2011
ABSTRACT
Journal of Applied Entomology, 1988
ABSTRACT
Journal of Animal Ecology, 2011
1. Priority effects have been hypothesized to have long-lasting impact on community structure in ... more 1. Priority effects have been hypothesized to have long-lasting impact on community structure in natural ecosystems. Long-term studies of priority effects in natural ecosystems are however sparse, especially in terrestrial ecosystems. 2. Wood decay is a slow process involving a high diversity of insect and fungus species. Species interactions that drive change in communities of insects and fungi during wood decay are poorly understood because of a lack of sufficient long-term studies. 3. In this paper, we followed the colonization and succession of wood-living insects and fungi on cut trees during 15 years, from tree death and onwards, in a boreal forest landscape. We test the long-term priority effects hypothesis that the identity and abundance of species that colonize first affect the colonization success of later-arriving species. We also hypothesize that species interact in both facilitative and inhibitory ways, which ultimately affect habitat quality for a red-listed late-succession beetle species. 4. Possible causal associations between species were explored by path analysis. The results indicate that one bark beetle species, Hylurgops palliatus, and one wood-borer species, Monochamus sutor, which colonized the wood during the first year after cutting, influenced the occurrence of a rare, wood-living beetle, Peltis grossa, that started to emerge from the stumps about 10 years later. The positive effects of Hylurgops palliatus and negative effects of M. sutor were largely mediated through the wood-decaying fungus species Fomitopsis pinicola. 5. The study shows that variable priority effects may have long-lasting impact on community assembly in decaying wood. The study also exemplifies new possibilities for managing populations of threatened species by exploring links between early, well-understood species guilds and late, more poorly understood species guilds.
Forest Ecology and Management, 2008
The availability of habitat for wood-dependent species has been greatly reduced in Fennoscandian ... more The availability of habitat for wood-dependent species has been greatly reduced in Fennoscandian boreal forests and hence the setting aside of forest land for conservation purposes is a common strategy. Here, we explore the biodiversity quality and conservation relevance of three categories of set-asides dominated by Norway spruce (nature reserves, woodland key habitats and retention patches, i.e. groups of living
Forest Ecology and Management, 1999
Relative population levels of the spruce bark beetle, Ips typographus (L.) (Coleoptera, Scolytida... more Relative population levels of the spruce bark beetle, Ips typographus (L.) (Coleoptera, Scolytidae) and associated insects were estimated in 12 spruce stands in central Sweden. Spruce bolts and window traps baited with semiochemicals were used for the monitoring. Six stands were unmanaged and had ongoing attacks on standing trees by I. typographus. This had led to an accumulation of dead spruce trees during several years. These six stands were compared pairwise with six old-managed stands with similar forest structure, but with no attacks during the previous years and with low amounts of dead trees. Catches of 17 species were included in a quantitative analysis. Four species, all known to be common predators in I. typographus galleries, were caught in signi®cantly higher numbers in the unmanaged stands (two-to three-fold difference). In contrast, the number of I. typographus caught was almost identical for the two stand types. Our results indicate that predators of the spruce bark beetle may be more sensitive to certain forestry operations than their prey. Caging or baiting of bolts strongly in¯uenced the colonization of predatory species and the number of I. typographus offspring that emerged. Compared to uncaged, unbaited bolts, offspring production was ca. 30% higher in bolts caged with a ®ne nylon netting and ca. 30% lower in uncaged bolts baited with ethanol and -pinene. No difference between stand types was found in the production of offspring by I. typographus in the bolts. In a multiple-regression analysis, including the density of certain predators and of I. typographus galleries, one factor, namely`Thanasimus larvae per bolt', could signi®cantly explain some of the variation in I. typographus offspring production in the 36 bolts. #
Forest Ecology and Management, 2009
Forest Ecology and Management, 1999
Attacks of bark-and wood-boring beetles on mechanically created high stumps of Norway spruce, Pic... more Attacks of bark-and wood-boring beetles on mechanically created high stumps of Norway spruce, Picea abies L. (Karst.), were studied in the provinces of Dalarna (Granga Èrde area) and Uppland (Fagero Èn) in central Sweden. The experiment included a total of 362 stumps in the Granga Èrde area as well as 48 stumps and 18 logs at Fagero Èn. Most inspections were conducted in the ®rst and second autumns following the cuttings made to create the stumps. All stumps were attacked by at least one species during the two-year period, and for almost all of them (95%) the initial attacks occurred in the ®rst summer. The most frequently encountered species on the stumps were the scolytids Ips typographus (L.), Pityogenes chalcographus (L.), Hylurgops palliatus (Gyll.), Orthotomicus spp., Trypodendron lineatum (Oliv.), Dryocoetes sp. and Polygraphus poligraphus (L.), and the cerambycids Tetropium spp. and Monochamus sutor (L.). Both the time of cutting and stump diameter in¯uenced beetle colonisation. I. typographus was not found in autumn-cut stumps, while Orthotomicus spp. was found more frequently in autumn-cut stumps than in spring-cut stumps. There was a positive relationship between I. typographus occupancy and stump diameter, while negative relationships were found between stump diameter and H. palliatus and T. lineatum occupancy. Most stumps (ca. 80%) were attacked by more than one bark-and wood-boring species in the ®rst summer. The proportion of stumps attacked was signi®cantly higher than the proportion of logs attacked for P. poligraphus, T. lineatum and Tetropium spp., whereas the opposite was true for I. typographus. The percentage of bark area utilised by I. typographus was signi®cantly higher in logs than in stumps. #