Simon Kärvemo

Swedish University of Agricultural Sciences | SLU · Department of Ecology

Ips typographus is the most important tree‐killing bark beetle in Europe. In the north, it overwinters either in the bark of its host tree or in the ground, while in central Europe, overwintering in trees is most common. Few studies have estimated winter mortality of I. typographus in northern Europe. Mortality of I. typographus adults overwinterin...

Because of their dependence on ambient temperature ectothermic animals can serve as sentinels of conservation problems related to global warming. Reptiles in temperate areas are especially well suited to study such effects, as their annual and daily activity patterns directly depend on ambient temperature. This study is based on annual data spannin...

Reliable assessment measures are crucial for tracking changes in biodiversity and for evaluating the state of biodiversity. Two of the main drivers of biodiversity are habitat heterogeneity and resource amount. These drivers are used as proxies of biodiversity but assessing both is costly, limiting their practical use. To test which of the drivers...

Non‐native tree species are widely used in forest plantations. This may have negative consequences for biodiversity. Hitherto, most studies have compared species diversity between native and non‐native forest stands, which makes it difficult to separate the impact of tree species per se from stand characteristics. Our study, conducted in the south...

Context Biodiversity is highly affected by industrial forestry, which leads to the loss and fragmentation of natural habitats. To date, most conservation studies have evaluated associations among a single species group, forest type, or spatial scale. Objective The objective was to evaluate the richness of multiple species groups across various for...

Genomic variation within and among populations is shaped by the interplay between natural selection and the effects of genetic drift and gene flow. Adaptive divergence can be found in small-scale natural systems even when population sizes are small, and the potential for gene flow is high, suggesting that local environments exert selection pressure...

The chytrid fungus Batrachochytrium dendrobatidis ( Bd ) has caused worldwide declines in amphibian populations. While Bd is widespread in southern and central Europe, its occurrence and distribution in northernmost Europe is mostly unknown. We surveyed for Bd in breeding anurans in Sweden by sampling 1917 amphibians from 101 localities and 3 regio...

The restoration of forest structure and function is increasingly being used in boreal forests in order to halt the loss of biodiversity. Often ecological restoration is aimed at increasing the volume of dead and dying trees to enhance the biodiversity of deadwood-dependent organisms, but it may also increase population sizes of pest bark beetle spe...

Amphibians are among the most threatened vertebrate taxa due to anthropogenic habitat change and emerging pathogens. The fungus Batrachochytrium dendrobatidis (Bd) may cause trade-offs between the immune responses and other important functions, such as mobility. The pool frog (Pelophylax lessonae) is red-listed in Sweden, and an earlier study cond...

Published by the British Herpetological Society We used externally applied transmitters to study movements of female grass snakes (Natrix natrix) during the egg-laying period in a near-urban landscape in Sweden. Half of the studied snakes were residents while the other half were translocated individuals with no previous experience of the area. As p...

The present study examines the hibernation habitats of the locally vulnerable pool frog (Pelophylax lessonae) in the northern parts of Uppland, Sweden. Temperature and light levels were recorded throughout hibernation. Each hibernation site also had a micro (similar habitat) and a macro habitat (different habitat) control location. Data on tree bas...

Human-induced changes of the environment, including landscape alteration and habitat loss, may affect wildlife disease dynamics and have important ramifications on wildlife conservation. Amphibians are among the vertebrate taxa most threatened by anthropogenic habitat change. The emerging fungal pathogen Batrachochytrium dendrobatidis (Bd) has caus...

Gaining ecological knowledge on movement patterns and habitat selection of the red-listed pool frog (Pelophylax lessonae) in Sweden is of importance for adapting forestry within its habitats. Forestry is one of the major threats to persistence of pool frogs in northern Uppland. Drainage ditching and timber harvesting in core habitats degrade breedi...

The fungal pathogen Batrachochytrium dendrobatidis (Bd) poses a major threat to amphibian populations. To assist efforts to address such threats, we examined differences in Bd host infection prevalence among amphibian species and its relations to both local environmental factors in breeding habitats and landscape variables measured at three scales...

Summary table over data: Including detected presence of chytrid (Bd), number of infected individuals (Bd+), number of non-positive individuals (Bd-), Bd infection prevalence per site including all species (prev all), species sampled 2015 (Species 2015) and 2016 (Species 2016): Bb = Bufo bufo, Bob = Bombina bombina, Bv = Bufotes variabilis, Ec = Epi...

Results from the local and landscape models at three spatial scales and associations with detected Bd infection prevalence in the four-species Bayesian mixed-effects models. Mean (post.mean), lower (l-95% CI) and upper (u-95% CI) 95% confidence intervals, effective sample sizes (eff.samp) and p-values (pMCMC). Prevalence in Bombina bombina is the i...

Six species and differences in detected Bd infection prevalence. Bayesian mixed-effects models of Bd-prevalence and the six species of amphibians with prevalence in Bombina bombina as the intercept against which prevalence in the other species was tested. Mean (post.mean), lower (l-95% CI) and upper (u-95% CI) 95% confidence intervals, effective sa...

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is a major threat to amphibian populations. Here we asked if the prevalence of Bd differs between amphibian species and whether it is related to local environmental factors in breeding habitats as well as landscape variables measured at three scales (500, 2000 and 5000 m radius) in southernmos...

The pool frog (Pelophylax lessonae) has a limited distribution in Scandinavia and is red-listed in Sweden. Most of the ~120 Swedish localities are concentrated along a limited coastline in south-central Sweden. The major threat to the species is loss of suitable habitat, e.g. due to forest drainage ditching and clear cutting. Understanding importan...

Forestry has significantly changed many boreal forest landscapes with negative effects on biodiversity. Main reasons are habitat loss and deterioration, due to a simplified forest composition, including a reduction in old trees and dead wood. In Sweden, measures to counter the loss of biodiversity are taken at forest harvesting, and include forest...

Forestry has markedly changed a large proportion of the world's boreal forests, often with negative effects on biodiversity. As a result, forest restoration is increasingly implemented to counteract the negative effects. However, restoration measures aimed at mimicking natural disturbance regimes could simultaneously increase the risk of unwanted n...

Forest pest insects may cause large-scale tree growth reductions and tree mortality during outbreaks. The large-scale development of outbreaks has frequently been studied, while the colonization-extinction dynamics during outbreaks is less known. We study the colonization-extinction dynamics of a severe tree-killing bark beetle, Ips typographus, du...

The European spruce bark beetle Ips typographus (L.) is one of the most important pests of mature Norway spruce in Europe. Outbreaks are often triggered by large-scale storm disturbances, which provide the beetles with a large surplus of suitable breeding material in the form of wind-felled spruces in storm gaps. Due to high reproductive success in...

Bark beetle outbreaks have increased in Europe and North America. To mitigate damage efficiently during outbreaks, robust models predicting where the risk for tree mortality is highest across forest landscapes and better understanding of the underlying mechanisms are required. Using Boosted Regression Trees, we modelled relative risks of infestatio...

Populations of snakes and other reptiles are declining worldwide. Habitat loss and degradation is thought to be a significant factor in these declines, so to improve management strategies it is important to increase our understanding of reptilian habitat requirements. Modern agriculture is abandoning the tradition of gathering compost and manure in...

In this paper we show that the number of grass snake (Natrix natrix L.) specimens deposited in Swedish museum collections has declined in the last eighty years, and that this is correlated with a dramatic national decrease in the number of livestock holdings. These results support the hypothesis that Swedish grass snakes are declining and that this...

Dice snakes (Natrix tessellata) can reach exceptionally large population densities where local conditions permit. Here we report on a study of one large population from Histria, the southern-most area of the Danube Delta in Romania. There the dice snakes forage in the brackish waters of Lake Sinoe. Many snakes are visibly infected by parasitic nema...

An archaeological excavation site among ancient ruins in Histria, south-eastern Romania, that harbours several thousand dice snakes (Natrix tessellata), is the focus of various ongoing studies. The current work evaluates seasonal variation of gender specific movements. Seasonal movements were estimated from captures of adult snakes over four years....

1. A lack of warm nest-sites prevents oviparous reptile species from reproducing in cool climates; such areas are dominated by viviparous species because sun-seeking pregnant females can maintain high temperatures for their developing offspring. 2. Our field and laboratory studies show that one oviparous species (the grass snake, Natrix natrix) esc...

The European spruce bark beetle (Ips typographus) and the North American mountain pine beetle (Dendroctonus ponderosae) may kill millions of trees during outbreak periods. Both species have also experienced large outbreaks in recent years. But the magnitude of the outbreaks of D. ponderosae is much larger. In this review we compare the outbreak his...

During an extensive study regarding the epidemiology of larval Eustrongylides infestation in a free-ranging endangered population of dice snakes (Natrix tessellata) from Histria, Romania, an adult female was euthanized to evaluate pathologic changes. Parasites appeared as nodules at various locations: in subcutaneous connective tissues, on the sero...

During outbreak periods, the European spruce bark beetle and the North American mountain pine beetle are able to kill millions of coniferous trees. Throughout the 20th century, six outbreaks have occurred in Sweden and four in British Columbia, with about 20-year intervals in both regions. The outbreaks of the mountain pine beetles seem to grow muc...