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Dive into the research topics where Göran Sahlén is active.

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Featured researches published by Göran Sahlén.


Archive | 2010

European Red List of dragonflies

Göran Sahlén; Vincent J. Kalkman; Jean-Pierre Boudot; Rafał Bernard; Klaus-Jürgen Conze; Geert De Knijf; Elena S. Dyatlova; Sónia Ferreira; Miloš Jovic; Jürgen Ott; Elisa Riservato

The European Red List is a review of the conservation status of c.6,000 European species (mammals, reptiles, amphibians, freshwater fishes, butterflies, dragonflies, and selected groups of beetles, ...


Insect Conservation and Diversity | 2008

Dragonfly community re‐organisation in boreal forest lakes: rapid species turnover driven by climate change?

Ida Flenner; Göran Sahlén

Abstract. 1  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. 2 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. 3 We explored effects on regional species composition, species abundance and ecosystem functions, such as changes in niche use, utilising dragonflies (Odonata) as model organisms. 4 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. 5 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.


International Journal of Odonatology | 2004

Critical species of Odonata in Europe

Göran Sahlén; Rafał Bernard; Adolfo Cordero Rivera; Robert Ketelaar; Frank Suhling

Abstract The status of the odonate fauna of Europe is fairly well known, but the current IUCN Red List presents only six species out of ca 130, two of which are actually out of danger today. In this paper we propose a tentative list of 22 possibly declining or threatened species in the region. For the majority, reliable data of population size and possible decline is still lacking. Also 17 endemic species are listed, most occurring in the two centres of endemism in the area: the south-eastern (mountains and islands) and the western Mediterranean. These species should receive extra attention in future updates of the world Red List due to their limited distribution. The extreme variation in biomes and the human exploitation of habitats make conservation planning complicated in Europe. Within the EU, the FFH directive is a working tool aiding conservation. However, the species included do not fully correspond to those on the current Red List, nor to those discussed in this paper. We believe that future conservation efforts should focus on the most valuable and threatened habitats in each sub-region. Active conservation measures could be implemented on a European scale, provided that research will establish a solid ground for such measures.


Insect Conservation and Diversity | 2010

Does one community shape the other? Dragonflies and fish in Swedish lakes

Torben Wittwer; Göran Sahlén; Frank Suhling

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.


Insect Conservation and Diversity | 2014

Farmland versus forest: comparing changes in Odonata species composition in western and eastern Sweden

Kamilla Koch; Christine Wagner; Göran Sahlén

Despite the loss of natural ecosystems in the developed world during the past millennia, anthropogenic landscapes still sustain much biodiversity. Our question was, whether ten year changes in regional Odonata faunas are comparable between farmland and forested areas, or if the species pool of farmland areas respond in other ways than that of forest. We used data of dragonfly larvae collected from 16 lakes in a farmland area in south‐western Sweden in the years 2002 and 2011/12, and compared these to data from 34 lakes in a forest area in south‐eastern Sweden in the years 1996 and 2006. The species‐richness in the agricultural region increased by 17% but decreased by 13% in the forested region. The changes in occurrence and regional distribution were similar in both areas, affecting 71% and 69% of the species pool. Average extinction rates were comparable between the agricultural and the forested region (38% and 43%) while colonisation rates differed greatly (64% and 114%). The species composition differed between the regions; the forest lakes harboured a 29% larger species pool. It is possible that in the forested region, the regional species pool in areas surrounding the study sites could stabilise the extinction and have a positive effect on changes in species composition. We assume that the different habitat structures of the waters in the agricultural and the forest regions and changes in temperature are the main driving forces behind the shifts. The mean seasonal air temperature has increased by circa 0.5 °C in both regions, when comparing ten‐year periods before each sampling year.


Ecological Entomology | 2009

Predator-induced spine length and exocuticle thickness in Leucorrhinia dubia (Insecta: Odonata): a simple physiological trade-off?

Ida Flenner; Karin Olne; Frank Suhling; Göran Sahlén

1. Morphological defence structures evolve against predators but are costly to the individual, and are induced only when required. A well‐studied example is the development of longer abdominal spines in dragonfly larvae in the presence of fish. Numerous attempts to discover trade‐offs between spine size and behaviour, development time or body size have, however, produced little evidence.


Upsala Journal of Medical Sciences | 2010

Secretions from seminal vesicles lack characteristic markers for prostasomes

Göran Sahlén; Ove Nilsson; Anders Larsson; Lena Carlsson; Bo Johan Norlén; Gunnar Ronquist

Abstract Background. Prostasomes are suggested to be produced in the prostate gland. Although biochemical studies support this, some immunohistochemical findings indicate that also the seminal vesicles could be a source of prostasomes. Therefore, we have compared the secretion of the vesicles with that of the prostate using biochemical and ultrastructural techniques. Methods. Ultracentrifuged pellets of substance from seminal vesicle secretions were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and flow cytometry. The secretory cells of the seminal vesicles were examined with transmission electron microscopy. These findings were then compared with published results from similar studies of the prostate secretory cells. Results. In SDS-PAGE, the seminal vesicle pellets lacked the three prostasome-characteristic CD-markers, namely CD10, CD13, and CD26, but expressed two proteins of about 55 kDa and 70 kDa, corresponding to clusterin and heat shock protein (HSP70). Flow cytometry showed the presence of secretion particles in the seminal pellet, although of a smaller size than that of the prostasomes. Electron microscopy of the luminal part of the cells in the seminal vesicles demonstrated many secretion granules, each enclosed in a vesicle with a size of about 1 μm. Conclusions. Pelleted seminal vesicle secretion is different to prostate secretion in several ways. No prostasome characteristics were detected in the pelleted seminal vesicle secretion.


PLOS ONE | 2016

A Global Population Genetic Study of Pantala flavescens

Daniel Troast; Frank Suhling; Hiroshi Jinguji; Göran Sahlén; Jessica L. Ware

Among terrestrial arthropods, the dragonfly species Pantala flavescens is remarkable due to their nearly global distribution and extensive migratory ranges; the largest of any known insect. Capable of migrating across oceans, the potential for high rates of gene flow among geographically distant populations is significant. It has been hypothesized that P. flavescens may be a global panmictic population but no sufficient genetic evidence has been collected thus far. Through a population genetic analysis of P. flavescens samples from North America, South America, and Asia, the current study aimed to examine the extent at which gene flow is occurring on a global scale and discusses the implications of the genetic patterns we uncovered on population structure and genetic diversity of the species. This was accomplished using PCR-amplified cytochrome oxidase one (CO1) mitochondrial DNA data to reconstruct phylogenetic trees, a haplotype network, and perform molecular variance analyses. Our results suggested high rates of gene flow are occurring among all included geographic regions; providing the first significant evidence that Pantala flavescens should be considered a global panmictic population.


International Journal of Odonatology | 2003

An extended description of the larva of Megaloprepus caerulatus from Costa Rica (Odonata: Pseudostigmatidae)

Ingemar Hedström; Göran Sahlén

Abstract The larva of Megaloprepus caerulatus is described and illustrated from specimens collected near the northern border of Barbilla National Park on the Costa Rican Caribbean slope. Habits and characters of larvae of three different size classes obtained from artificial tree holes permit the identification of small (body length 4 mm, excluding the caudal lamellae) larvae up to the final stadium. New diagnostic characters include the shape of the prementum and head.


Systematic Entomology | 2016

For consistency's sake? A reply to Bybee et al.

Göran Sahlén; Frank Suhling; Andreas Martens; Stanislav N. Gorb; Ola M. Fincke

1Ecology and Environmental Science, Halmstad University, Halmstad, Sweden, 2Institut für Geoökologie, Technische Universität Braunschweig, Braunschweig, Germany, 3Institut für Biologie und Schulgartenentwicklung, Pädagogische Hochschule Karlsruhe, Karlsruhe, Germany, 4Zoological Institute: Functional Morphology and Biomechanics, Kiel University, Kiel, Germany and 5Ecology and Evolutionary Biology Program, Department of Biology, University of Oklahoma, Norman, OK, U.S.A.

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Gunnar Ronquist

Uppsala University Hospital

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Frank Suhling

Braunschweig University of Technology

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Anders Larsson

Uppsala University Hospital

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