| 1. |
- Nilsson, Sven, et al.
(författare)
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Long-term land-use changes and extinction of specialised butterflies
- 2008
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-4598 .- 1752-458X. ; 1:4, s. 197-207
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Tidskriftsartikel (refereegranskat)abstract
- 1. Land-use change in 450 ha in southern Sweden between 1814 and 2004 was recorded. Butterflies and burnet moths were surveyed in 1904–1913 and 2001–2005. 2. We explore if local extinctions were related to land-use changes and species attributes. 3. Land use changed drastically over the 190-year period, and the largest relative change occurred for hay meadows with late harvest, which decreased from 28% to 0%. The area changed from grasslands and grazed forests to being dominated by timber forests. Previous open grazed mixed woodlands changed to spruce plantations with clear-cuts. 4. Of the 48 resident butterfly and burnet moths found a century ago, 44% have become extinct. The extinct Aporia cratægi, Colias palaeno, and Leptidea sinapis were abundant 100 years ago and had their highest densities in flower-rich glades in forest, a habitat which no longer exists. 5. The butterfly extinctions could be predicted from species-specific attributes as a short flight length period (P < 0.02), narrow habitat breadth (P < 0.02), small distribution area in Europe (P = 0.033) and possibly larvae food plant nitrogen class (P < 0.06). In a multiple logistic regression, the flight length period was the only significant variable because the independent variables were intercorrelated. 6. We conclude that the most important factor explaining the high extinction rate is that flower-rich habitats have disappeared from both woodlands as well as from open farmlands. The most sensitive species are specialised species with a short summer flight which have gone extinct. Only the most unspecialised species still persist in the current landscape.
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| 2. |
- Wittwer, Torben, et al.
(författare)
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Does one community shape the other? Dragonflies and fish in Swedish lakes
- 2010
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Ingår i: Insect Conservation and Diversity. - London : Wiley. - 1752-4598 .- 1752-458X. ; 3:2, s. 124-133
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Tidskriftsartikel (refereegranskat)abstract
- 1. Freshwater communities are often structured by predation. In permanent lentic freshwater habitats dragonfly larvae are major predators which, in return, suffer predation by fish. Antipredator traits vary between the dragonfly species, and the dragonfly communities are therefore shaped by the presence of fish. But fish communities vary, and as different fish species affect dragonflies in different ways, the species composition of the fish community may affect the composition of the dragonfly community. 2. We sampled dragonfly larvae in 24 lakes with a known fish stock in south-western Sweden, and explored the impact of fish as well as vegetation structure on dragonfly communities by means of multivariate analyses. 3. We found that the presence of four fish species affected the community structure of dragonflies. The impact strength depended mainly on the abundance of Perca fluviatilis, with which most dragonfly species were negatively correlated. Many dragonfly species were also positively correlated with the occurrence of at least one fish species, which may reflect similar habitat requirements or imply indirect positive effects of these fish species. 4. Of the 24 recorded dragonfly species, four did not occur in lakes dominated by P. fluviatilis, whereas only one species was lacking in lakes dominated by Rutilus rutilus. The dragonfly species diversity was higher in R. rutilus lakes than in P. fluviatilis lakes. 5. Our results suggest that the fish species composition is a major determinant of the dragonfly community, which in turn will influence the lower trophic levels.
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| 3. |
- Abrahamsson, Markus, et al.
(författare)
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Saproxylic beetle assemblages in artificially created high-stumps of spruce (Picea abies) and birch (Betula pendula/pubescens) – does the surrounding landscape matter?
- 2009
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 2, s. 284-294
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Tidskriftsartikel (refereegranskat)abstract
- Abstract. 1. To create high-stumps (snags) is a common conservation action during final felling in Swedish production forests. However, many wood-living beetle species are only found in certain areas with higher overall biodiversity, so called hotspots. It has been argued that it is efficient to concentrate conservation efforts to hotspots. 2. The saproxylic beetle fauna was sampled on ten clearcuts inside hotspots and ten clearcuts outside the hotspots. They were collected with window traps mounted on 2- and 4-year-old spruce and birch high-stumps. We also used environmental data (e.g. tree species composition) to confirm differences between the surroundings of two, the clearcut types. 3. High-stumps on the hotspot clearcuts did not attract more saproxylic beetle species, or red-listed species, than high-stumps outside the hotspots. The environmental data showed that the clearcuts differed in several important aspects, for instance, were there a higher proportion of broadleaved trees around the hotspot compared with the clearcuts outside the hotspots. In a Canonical Correspondence Analysis, the proportion of coniferous and broadleaved forest was an important explanatory variables. The hotspot variable did contribute significantly in explaining the beetle composition on the birch high-stumps, but not on the spruce high-stumps. 4. In general, the study suggests that concentrating high-stumps to hotspot areas will not benefit more species. However, the result indicates birch high-stumps could be prioritised in a biologically rich landscape. The hotspot effect may be more noticeable in the future as the high-stumps decay and their importance for late successional species increase
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| 4. |
- Haaland, Christine
(författare)
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Sown wildflower strips for insect conservation: a review
- 2011
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 4, s. 60-80
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Forskningsöversikt (refereegranskat)abstract
- 1. Sown wildflower strips are increasingly being established in European countries within agri-environmental schemes to enhance biodiversity, especially in intensively used agricultural areas. 2. The regulations vary between countries regarding the seed mixture, intensity of management and period of time over which subsidies are given. Insects in particular are intended to benefit from these schemes. 3. This review treats studies of insect diversity and abundance in sown wildflower strips. Schemes on wildflower strips in several countries in Central and Northern Europe are compared. 4. In a significant majority of studies, sown wildflower strips support higher insect abundances and diversity than cropped habitats. In general, numbers and diversity also tend to be higher than in other margin types such as sown grass margins and natural regeneration, but pollen- and nectar-rich flower mixtures may outperform them. 5. Common species are the main beneficiaries of the establishment of wildflower strips, although some studies point out the presence of rare or declining insect species. 6. Insect groups respond differently to particular characteristics of the strips. Flower abundance, seed mixture, vegetation structure, management, age and landscape have been identified as factors influencing insect abundance and diversity. 7. Future work should address under-represented comparisons, such as with pollen- and nectar-rich seed mixes, and neglected groups, in particular parasitoids. Nevertheless, sown wildflower strips can already be seen as a beneficial measure to enhance insect diversity. This is especially the case, where schemes for sown strips vary within a region to favour different species groups
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| 5. |
- Stenbacka, Fredrik, et al.
(författare)
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Saproxylic parasitoid (Hymenoptera, Ichneumonoidea) communities in managed boreal forest landscapes
- 2010
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 3, s. 114-123
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Tidskriftsartikel (refereegranskat)abstract
- 4. The general distribution pattern revealed no significant differences in species richness among stand types, but parasitoid assemblages were affected by forest successional stage. Idiobionts, dominated by Ontsira antica and Bracon obscurator, preferred clear-cuts over forested sites, while koinobionts, especially Cosmophorus regius, were more common in mature forests and reserves. We conclude that the stand types studied were complementary in assemblage composition, but that none held a complete assemblage of saproxylic parasitoids and we suggest that a range of successional stages be retained to help conserve the entire parasitoid community.
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| 6. |
- Brunet, Jörg
(författare)
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Implications from large-scale spatial diversity patterns of saproxylic beetles for the conservation of European Beech forests
- 2013
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 6, s. 162-169
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Tidskriftsartikel (refereegranskat)abstract
- . 1.European Beech (Fagus sylvatica) is the natural dominant tree species in many forests across Europe. Despite Europe's global responsibility for these forests, the correct conservation strategies are still a matter of debate. In particular, it remains controversial whether high conservation efforts should be directed towards beech forests, owing to the small number of insects that are Fagus specialists, and at what spatial scale conservation should take place. 2.To provide evidence for this discussion, we compiled saproxylic beetle data from 1115 flight-interception traps in eight countries and addressed two main questions: (i) what percentage of central European species can be expected in beech-dominated forests? and (ii) which are the important spatial scales for the conservation of biodiversity in beech-dominated forests?3.We included six spatial scales in our analysis: among traps, forest stands, forest sites, low/high elevations, oligo/eutrophic soils, and European bioregions. 4.By extrapolating species numbers, we showed that 70% of the central European saproxylic beetle species can be expected in beech-dominated forests. Multiplicative -diversity partitioning revealed the forest site level as the most important diversity scale for species richness, particularly for red-listed and rare species, followed by elevation and bioregion. 5.We conclude that beech-dominated forests form a useful umbrella for the high species diversity of central European saproxylic beetles. Conservation activities, such as protecting areas or increasing dead wood, should be undertaken in as many forest sites as possible, at different elevations, and in different bioregions. For this, the Natura 2000 net may provide the most useful template.
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| 7. |
- Flenner, Ida, 1976-, et al.
(författare)
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Dragonfly community re-organisation in boreal forest lakes : rapid species turnover driven by climate change?
- 2008
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Ingår i: Insect Conservation and Diversity. - Oxford : Blackwell Publishing. - 1752-458X .- 1752-4598. ; 1:3, s. 169-179
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Tidskriftsartikel (refereegranskat)abstract
- Climate change affects many ecosystems on earth. If not dying out or migrating, the species affected have to survive the altered conditions, including changes in community structure. It is, however, usually difficult to distinguish changes caused by a changing climate from other factors.Forestry is considered to be the major disturbance factor in Swedish forests. Here, we use forest lake data sets from 1996 and 2006 which include species abundance data for dragonfly larvae, water plant structure, forest age and forestry measures during a period of 25 years: from 1980 to 2005. Hence, we were able to discriminate between forestry effects and changes in species composition driven by recent climate change.We explored effects on regional species composition, species abundance and ecosystem functions, such as changes in niche use, utilising dragonflies (Odonata) as model organisms.Our results show that dragonflies react rapidly to climate change, showing strong responses over such a short time span as 10 years. We observed changes in both species composition and abundance; former rare species have become more frequent and now occur in lakes of a wider quality range, while former widespread species have become more selective in their choice of waters. The new communities harbour about the same number of species as before, but seen from a regional perspective, diversity is reduced.We predict that the altered species composition and abundance might raise new demands in conservation planning as well as altering the ecological functions of the aquatic systems.
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| 8. |
- Johansson, Therese, et al.
(författare)
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Short-term responses of beetle assemblages to wildfire in a region with more than 100 years of fire suppression
- 2011
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 4:2, s. 142-151
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Tidskriftsartikel (refereegranskat)abstract
- 1. Suppression of wildfires in boreal landscapes has become widespread and has seriously affected many fire favoured species. However, little is known about the response of organism assemblages to large wildfires in regions with a long history of effective fire suppression, such as Scandinavia.2. We studied the short-term effects of a >1600 ha wildfire on beetle assemblages in northern Sweden. The first summer after fire, beetles were sampled in 12 sites using 36 large window traps, half in old pine forest stands in the burned area and half in similar, but unburned control stands. The entire beetle assemblage and eight subgroups were analysed: saproxylics, non-saproxylics, moderately fire favoured, strongly fire favoured, fungivores, predators, cambium consumers and red-listed species.3. Species composition differed markedly between burned and unburned forests in all nine groups. Furthermore, beetle abundance was higher in the burned area for the entire assemblage and for saproxylics, both groups of fire favoured species, predators and cambium consumers. Species number was higher only for non-saproxylics, strongly fire favoured species and cambium consumers.4. Our results show that wildfire has rapid and strong effects on a wide range of beetles. However, we only trapped two individuals of fire-dependent beetles, which may suggest a lack of such species in the region, possibly due to >100 years of fire suppression. At the regional scale, the studied wildfire may potentially increase the abundance of these beetles after a longer period of reproduction in the burned area.
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| 9. |
- Marini, Lorenzo, et al.
(författare)
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High mobility reduces beta-diversity among orthopteran communities - implications for conservation
- 2012
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 5, s. 37-45
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Tidskriftsartikel (refereegranskat)abstract
- 5. Measures currently included in most agri-environment schemes have only focused on the extensive management at the field scale. Our results imply that orthopteran diversity would benefit from maintaining extensively managed meadows scattered throughout the whole region, as the loss of species-rich isolated grassland patches due to abandonment or eutrophication might cause severe reductions of the regional species pool. Increasing connectivity might be also considered as a complementary measure to increase species occupancy and population persistence, particularly for sedentary species.
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| 10. |
- Ranius, Thomas
(författare)
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Dispersal patterns of a saproxylic beetle, Osmoderma eremita, in Mediterranean woodlands
- 2013
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 6, s. 309-318
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Tidskriftsartikel (refereegranskat)abstract
- Dispersal patterns of a beetle inhabiting tree hollows, Osmoderma eremita (Scopoli, 1763) (Coleoptera: Cetoniidae), were studied in a cork oak (Quercus suber) woodland in central Italy, the southernmost part of its distribution range. During 2years, we used radio telemetry to monitor dispersal of 39 free-ranging individuals (16 males, 23 females). Telemetered beetles spent their lifetime not only inside hollow trees but also in other habitats, such as above or under the ground surface. Beetles were more active at the beginning of the season. Eighty-one per cent of the males and 69% of the females conducted dispersals during their lifetime. The dispersal distance over individuals' lifetime did not differ between sexes. The longest dispersal was conducted by a female that moved 1504m. Thirty-nine per cent of dispersing individuals reached distances farther than 250m. Both dispersal rate and range are higher than what has been found in Northern Europe. The population size per tree is low, most of the adults leave their natal tree, and a high predation rate (at least 28%) was observed among dispersing beetles. Therefore, to balance the local extinction risk from single trees, a high density of hollow trees is probably required. It is desirable that suitable trees are concentrated at a spatial scale of a few hundred metres.
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