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Lars Mørch Korslund

Associate Professor Department of Natural Sciences

Email: lars.korslund@uia.no
Phone: +47 38 14 16 40
Mobile phone: +47 40 21 53 45
Office: J1019 (Universitetsveien 25, 4630 Kristiansand, Norway)

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Background and experience

I am an ecologist specializing in marine and freshwater systems, with a particular focus on fish ecology, bioacoustics, and telemetry-based approaches.

I hold an M.Sc. in Biology and a Ph.D. in Ecology (2006) from the University of Oslo. Following my Ph.D., I worked as a researcher at the Centre for Ecological and Evolutionary Synthesis (CEES) and completed a postgraduate teaching qualification. I have been a at the Department of Natural Sciences at UiA since 2009.

Areas of responsibility

I currently serve as Deputy Chair of the Centre for Coastal Research (CCR) and Deputy Head of the Department of Natural Sciences.

Teaching

I teach and contribute to several courses at UiA, including:

BIO112 – Introduction to Biology
BIO206 – General Ecology
BIO300 – Bachelor’s Thesis in Biology
BIO413 – Coastal Benthic Ecology
BIO414 – Pelagic Ecology
BIO415 – Study Design, Data Analysis, and Reproducible Science

My teaching emphasizes quantitative skills, inquiry-based learning, ecological understanding, and reproducible science.

I supervise bachelor’s and master’s students every year, usually in connection with my ongoing research projects. Prospective students are very welcome to get in touch if they are interested in a thesis within my research areas.

Research

I primarily study marine and aquatic ecosystems. My work centers on fish ecology and integrates multiple methodological approaches, including passive acoustic monitoring, acoustic telemetry, and genetics.

Bioacoustics and Ecoacoustics

A major part of my research uses Passive Acoustic Monitoring (PAM) to study sound production and communication in fish and, to some extent, amphibians. My research spans both bioacoustics and ecoacoustics and addresses:

Why, how, and when animals use sound
How acoustic communication influences population ecology and evolution
How sound can be used to monitor biodiversity and ecosystem state
The impacts of anthropogenic noise on individuals, populations, and ecosystems

These approaches generate large volumes of data, and I collaborate with colleagues to develop and apply deep learning tools for efficient data processing and analysis.

Left: Sea surface temperature (red) and Acoustic Complexity Index (ACI - a measure of activity of soniferous species - orange) through the month of May 2023 in a coastal ecosystem in Southern Norway. ACI is calculated individually (white dots) for each 1-minute sound recording, between 12.00 and 13.00 every day. In periods like this, when the water temperature changes relatively quickly between 7 and 14 degrees, the activity of soniferous fish, and therefore the soundscape as a whole, are strongly affected by the ambient temperature. The data were recorded at 3 meters depth.
Right: A spectrogram of the mating call of a male pool frog (Pelophylax lessonae) recorded in Arendal, Norway June 1, 2020. The males call intensively, to attract females and to intimidate competing males, during the spawning season in May and June, often producing large choruses, and sometimes this can be heard more than a kilometer away.

Salmonids and Coastal Ecosystems

I also study salmonids—particularly brown trout (Salmo trutta) and Atlantic salmon (Salmo salar) - in coastal ecosystems, including rivers and streams. These species depend on both freshwater and marine habitats, and small coastal systems are often heavily affected by human infrastructure. My research focuses on how environmental conditions and human impacts influence competition, migration behavior, and life-history strategies. A key goal is to improve our understanding of these processes to support effective management and conservation.

Saha, Atal; Jorde, Per Erik; Sodeland, Marte; Albretsen, Jon; Korslund, Lars & Knutsen, Halvor (2025). Genomic population structure and local adaptation in the emerging commercially exploited Littorina littorea. ICES Journal of Marine Science. ISSN 1054-3139. 82(7). doi: 10.1093/icesjms/fsaf119. Full text in Research Archive Show summary
To address food deficit, stakeholders continuously diversify food systems by exploiting new commercially viable species. However, the absence of sustainable management measures often conflicts with global biodiversity policies. In light of this challenge, understanding genetic diversity and the geographic scale of population connectivity is essential. We employ ddRAD sequencing in Littorina littorea, a low-trophic, emerging commercial species, to investigate its genetic population structure in Norwegian coastal waters. From an initial detection of over two million SNPs (single nucleotide polymorphisms), 60 831 loci were retained for downstream genomic analyses in 189 individuals sampled across 17 coastal sites. Our results revealed significant isolation-by-distance across the study area, likely reflecting genetic divergence between populations along the west and southern coasts of Norway. While the overall genetic structure appears to be primarily shaped by genetic drift, our genome scan analyses provided evidence for selection acting on specific loci. We identified 39 SNPs potentially under selection, of which 16 overlapped with genes encoding proteins involved in transmembrane transport, metabolic processes, and pathogenesis-related functions. We found no evidence supporting the presence of chromosomal inversions. Oceanographic modelling suggests a likely link between observed genetic divergence and the prevailing ocean current in the region. Our findings demonstrate the adaptive potential of distinct populations to varying environmental conditions and highlight the importance of preserving their full genetic diversity to ensure long-term resilience and sustainability.
Saha, Atal; Jorde, Per Erik; Sodeland, Marte; Korslund, Lars & Knutsen, Halvor (2025). Pelagic Larval Duration and Isolation by Distance in Coastal Species. Evolutionary Applications. 18(12). doi: 10.1111/eva.70187. Full text in Research Archive Show summary
Dispersal among populations is crucial both for demographic stability and for the evolutionary potential of species. In marine organisms, dispersal has been shown to be prevalent during pelagic early life stages. Consequently, pelagic larval duration (PLD) has been proposed as an important driver of gene flow in marine species and is influencing genetic differentiation among populations. Despite this prediction, empirical studies have often failed to find the expected correlation between PLD and genetic metrics of gene flow. This could mean either that PLD is a poor predictor of gene flow or that differences in methodology, oceanography or sampling design across studies obscure the underlying mechanisms of gene flow. In the present study, we address these issues by using a consistent sampling design for 10 coastal species with previously published genetic data (ddRAD and microsatellites), and that differ in PLD. We investigate gene flow using an isolation-by-distance (IBD) model with pairwise FST-estimates regressed against distances measured along the prevailing coastal ocean current in the study region. We find a significant (p < 0.05) correlation between species' PLD and IBD slopes, with a moderately strong correlation (r2 > 0.5), These findings support the notion of PLD as a key factor determining dispersal and gene flow among populations of coastal species. Our findings reiterate genetics as a useful tool for inferring population dispersal in marine organisms when potentially confounding factors are eliminated by adopting a consistent sampling design.
Reamon, Molly Claire; Marcussen, Johanna Bjånes; Laugen, Ane Timenes & Korslund, Lars (2024). Efficient and reliable methods for estimating the abundance of keystone coastal macrofauna over large spatial scales. Ecology and Evolution. 14(8), p. 1–15. doi: 10.1002/ece3.70088. Full text in Research Archive Show summary
Coastal bivalves are important ecosystem engineers, and identifying critical habitats can enhance conservation outcomes for threated keystone species as well as determining hotspots for invasive species. As early action is more efficient in both conservation and mitigation of species invasions, efficient and reliable tools for mapping and monitoring species over large scales are essential. We assessed the reliability and efficiency of towed video and quadrat sampling for estimating the abundance of three keystone macrofaunal bivalve species. To assess reliability, we compared the measured density based on each of the two methods to the “true” density estimated by manually surveying an entire transect. We found that both the video and quadrat method caused underestimation of the density of bivalves, but that the amount of underestimation was comparable, and further that both methods took substantially less time than surveying an entire transect manually. The video method underestimated the abundance of Pacific oysters (Magallana gigas), European flat oysters (Ostrea edulis), and blue mussels (Mytilus spp.) by 23%, 24%, and 16%, respectively. The causes of underestimation for the two oyster species were bivalves grouped in clusters, large amounts of small individuals, and generally higher abundances. While Mytilus spp. were underestimated overall, here observer experience was important, with inexperienced observers overestimating and experienced observers underestimating. Our study found both methods to be reliable and efficient for estimating the abundance of three keystone macrofaunal species, suggesting their potential applicability to other sessile or slow-moving species. We propose that these methods, due to their efficiency, can advance scientific knowledge and enhance conservation outcomes by establishing population baselines, assessing trends over time, and identifying and protecting critical habitats.
Evensen, Vetle Nesland; Henriksen, Gabriel Bergman; Melhus, Sondre; Olsen, Ole Steine; Haugen, Kristina & Dolmen, Dag [Show all 11 contributors for this article] (2023). ReFrogID: Pattern Recognition for Pool Frog Identification Using Deep Learning and Feature Matching. Lecture Notes in Computer Science (LNCS). ISSN 0302-9743. 14381, p. 365–376. doi: 10.1007/978-3-031-47994-6_33. Full text in Research Archive Show summary
The global decline in amphibian populations is a pressing issue, with numerous species facing the threat of extinction. One such species is the pool frog, Pelophylax lessonae, whose Norwegian population has experienced a significant long-term decline since monitoring began in 1996. This decline has pushed the species to the verge of local extinction. A substantial knowledge gap in the species’ biology hinders the proposal and evaluation of effective management actions. Consequently, there is a pressing need for efficient techniques to gather data on population size and composition. Recent advancements in Machine Learning (ML) and Deep Learning (DL) have shown promising results in various domains, including ecology and evolution. Current research in these fields primarily focuses on species modeling, behavior detection, and identity recognition. The progress in mobile technology, ML, and DL has equipped researchers across numerous disciplines, including ecology, with innovative data collection methods for building knowledge bases on species and ecosystems. This study addresses the need for systematic field data collection for monitoring endangered species like the pool frog by employing deep learning and image processing techniques. In this research, a multidisciplinary team developed a technique, termed ReFrogID, to identify individual frogs using their unique abdominal patterns. Utilizing RGB images, the system operates on two main principles: (1) a DL algorithm for automatic segmentation achieving AP@89.147, AP50@99.123, and AP75@98.942, and (2) pattern matching via local feature detection and matching methods. A new dataset, pelophylax_lessonae, addresses the identity recognition problem in pool frogs. The effectiveness of ReFrogIDis validated by its ability to identify frogs even when human experts fail. Source code is available at here.
Lamsal, Alaka; Edgar, Kristin Skarsfjord; Jenkins, Andrew; Renssen, Hans; Kjær, Lene Jung & Alfsnes, Kristian [Show all 25 contributors for this article] (2023). Prevalence of tick-borne encephalitis virus in questing Ixodes ricinus nymphs in southern Scandinavia and the possible influence of meteorological factors. Zoonoses and Public Health. ISSN 1863-1959. 70(6), p. 473–484. doi: 10.1111/zph.13049. Full text in Research Archive Show summary
Ixodes ricinus ticks are Scandinavia's main vector for tick-borne encephalitis virus (TBEV), which infects many people annually. The aims of the present study were (i) to obtain information on the TBEV prevalence in host-seeking I. ricinus collected within the Øresund-Kattegat-Skagerrak (ØKS) region, which lies in southern Norway, southern Sweden and Denmark; (ii) to analyse whether there are potential spatial patterns in the TBEV prevalence; and (iii) to understand the relationship between TBEV prevalence and meteorological factors in southern Scandinavia. Tick nymphs were collected in 2016, in southern Scandinavia, and screened for TBEV, using pools of 10 nymphs, with RT real-time PCR, and positive samples were confirmed with pyrosequencing. Spatial autocorrelation and cluster analysis was performed with Global Moran's I and SatScan to test for spatial patterns and potential local clusters of the TBEV pool prevalence at each of the 50 sites. A climatic analysis was made to correlate parameters such as minimum, mean and maximum temperature, relative humidity and saturation deficit with TBEV pool prevalence. The climatic data were acquired from the nearest meteorological stations for 2015 and 2016. This study confirms the presence of TBEV in 12 out of 30 locations in Denmark, where six were from Jutland, three from Zealand and two from Bornholm and Falster counties. In total, five out of nine sites were positive from southern Sweden. TBEV prevalence of 0.7%, 0.5% and 0.5%, in nymphs, was found at three sites along the Oslofjord (two sites) and northern Skåne region (one site), indicating a potential concern for public health. We report an overall estimated TBEV prevalence of 0.1% in questing I. ricinus nymphs in southern Scandinavia with a region-specific prevalence of 0.1% in Denmark, 0.2% in southern Sweden and 0.1% in southeastern Norway. No evidence of a spatial pattern or local clusters was found in the study region. We found a strong correlation between TBEV prevalence in ticks and relative humidity in Sweden and Norway, which might suggest that humidity has a role in maintaining TBEV prevalence in ticks. TBEV is an emerging tick-borne pathogen in southern Scandinavia, and we recommend further studies to understand the TBEV transmission potential with changing climate in Scandinavia.
Halvorsen, Silje; Korslund, Lars; Mattingsdal, Morten & Slettan, Audun (2023). Estimating number of European eel (Anguilla anguilla) individuals using environmental DNA and haplotype count in small rivers. Ecology and Evolution. 13(2). doi: 10.1002/ece3.9785. Full text in Research Archive Show summary
Knowledge about population genetic data is important for effective conservation management. Genetic research traditionally requires sampling directly from the organism, for example tissue, which can be challenging, time-consuming, and harmful to the animal. Environmental DNA (eDNA) approaches offer a way to sample genetic material noninvasively. In attempts to estimate population size of aquatic species using eDNA, researchers have found positive correlations between biomass and eDNA concentrations, but the approach is debated because of variations in the production and degrading of DNA in water. Recently, a more accurate eDNA-approach has emerged, focusing on the genomic differences between individuals. In this study, we used eDNA from water samples to estimate the number of European eel (Anguilla anguilla) individuals by examining haplotypes in the mitochondrial D-loop region, both in a closed aquatic environment with 10 eels of known haplotypes and in three rivers. The results revealed that it was possible to find every eel haplotype in the eDNA sample collected from the closed environment. We also found 13 unique haplotypes in the eDNA samples from the three rivers, which probably represent 13 eel individuals. This means that it is possible to obtain genomic information from European eel eDNA in water; however, more research is needed to develop the approach into a possible future tool for population quantification.
Korslund, Lars; Floden, Marius Stener; Albertsen, Milla Mona Sophie; Landsverk, Amalie; Løkken, Karen Margrete Vestgård & Johansen, Beate Strøm (2023). Home Range, Movement, and Nest Use of Hedgehogs (Erinaceus europaeus) in an Urban Environment Prior to Hibernation. Animals. 14(1). doi: 10.3390/ani14010130. Full text in Research Archive Show summary
The West European hedgehog (Erinaceus europaeus) is in decline, and it is important to identify its challenges. We used VHF-telemetry to monitor pre-hibernation space use, nest use, and hibernation sites in a suburban area in Norway. Based on nine adult hedgehogs tracked between August and November 2002, we found that home range size was not dependent on individual sex or weight and that home ranges overlapped between individuals regardless of sex. The distance moved was not dependent on individual sex, but there was a tendency for increased movement before dawn. The number of nests used per individual (0–10) and the number of nest switches (0–14) varied greatly and did not differ significantly between sexes. Out of 28 nest sites, 16 were linked to buildings and 12 to vegetation, and nesting material was most often grass and leaves. Three hedgehogs monitored until hibernation established winter nests under tree roots in natural forest patches in September, and this suggests that establishing or maintaining forest patches in urban areas is important to ensure suitable hibernation habitat for hedgehogs. Our study was limited by a low sample size, and additional research is required to gain a deeper understanding of the challenges hedgehogs face in urban environments.
Pelsmaeker, Nicolas De; Korslund, Lars & Steifetten, Øyvind (2022). Host in reserve: The role of common shrews (Sorex araneus) as a supplementary source of tick hosts in small mammal communities influenced by rodent population cycles. Ecology and Evolution. 12(4), p. 1–12. doi: 10.1002/ece3.8776. Full text in Research Archive Show summary
Rodents often act as important hosts for ticks and as pathogen reservoirs. At north -ern latitudes, rodents often undergo multi- annual population cycles, and the peri -odic absence of certain hosts may inhibit the survival and recruitment of ticks. We investigated the potential role of common shrews (Sorex araneus) to serve as a sup -plementary host source to immature life stages (larvae and nymphs) of a generalist tick Ixodes ricinus and a small mammal specialist tick I. trianguliceps, during decreas-ing abundances of bank voles (Myodes glareolus). We used generalized mixed models to test whether ticks would have a propensity to parasitize a certain host species dependent on host population size and host population composition across two high- latitude gradients in southern Norway, by comparing tick burdens on trapped ani -mals. Host population size was defined as the total number of captured animals and host population composition as the proportion of voles to shrews. We found that a larger proportion of voles in the host population favored the parasitism of voles by I. ricinus larvae (estimate = −1.923, p= .039) but not by nymphs (estimate = −0.307,p= .772). I. trianguliceps larvae did not show a lower propensity to parasitize voles, regardless of host population composition (estimate = 0.875, p= .180), while nymphsparasitized shrews significantly more as vole abundance increased (estimate= 2.106, p= .002). These results indicate that common shrews may have the potential to act as a replacement host during periods of low rodent availability, but long- term observa-tions encompassing complete rodent cycles may determine whether shrews are able to maintain tick range expansion despite low rodent availability.
Pelsmaeker, Nicolas De; Korslund, Lars & Steifetten, Øyvind (2021). High-elevational occurrence of two tick species, Ixodes ricinus and I. trianguliceps, at their northern distribution range. Parasites & Vectors. 14(1), p. 1–14. doi: 10.1186/s13071-021-04604-w. Full text in Research Archive Show summary
Background During the last decades a northward and upward range shift has been observed among many organisms across different taxa. In the northern hemisphere, ticks have been observed to have increased their latitudinal and altitudinal range limit. However, the elevational expansion at its northern distribution range remains largely unstudied. In this study we investigated the altitudinal distribution of the exophilic Ixodes ricinus and endophilic I. trianguliceps on two mountain slopes in Norway by assessing larval infestation rates on bank voles (Myodes glareolus). Methods During 2017 and 2018, 1325 bank voles were captured during the spring, summer and autumn at ten trapping stations ranging from 100 m to 1000 m.a.s.l. in two study areas in southern Norway. We used generalized logistic regression models to estimate the prevalence of infestation of both tick species along gradients of altitude, considering study area, collection year and season, temperature, humidity and altitude interactions as extrinsic variables, and host body mass and sex as intrinsic predictor variables. Results We found that both I. ricinus and I. trianguliceps infested bank voles at altitudes up to 1000 m.a.s.l., which is a substantial increase in altitude compared to previous findings for I. ricinus in this region. The infestation rates declined more rapidly with increasing altitude for I. ricinus compared to I. trianguliceps, indicating that the endophilic ecology of I. trianguliceps may provide shelter from limiting factors tied to altitude. Seasonal effects limited the occurrence of I. ricinus during autumn, but I. trianguliceps was found to infest rodents at all altitudes during all seasons of both years. Conclusions This study provides new insights into the altitudinal distribution of two tick species at their northern distribution range, one with the potential to transmit zoonotic pathogens to both humans and livestock. With warming temperatures predicted to increase, and especially so in the northern regions, the risk of tick-borne infections is likely to become a concern at increasingly higher altitudes in the future.
Kjær, Lene Jung; Klitgaard, Kirstine; Soleng, Arnulf; Edgar, Kristin Skarsfjord; Lindstedt, Heidi Elisabeth Heggen & Paulsen, Katrine Mørk [Show all 17 contributors for this article] (2020). Spatial patterns of pathogen prevalence in questing Ixodes ricinus nymphs in southern Scandinavia, 2016. Scientific Reports. 10, p. 1–14. doi: 10.1038/s41598-020-76334-5. Full text in Research Archive
Halvorsen, Silje; Korslund, Lars; Gustavsen, Per Øyvind & Slettan, Audun (2020). Environmental DNA analysis indicates that migration barriers are decreasing the occurrence of European eel (Anguilla anguilla) in distance from the sea. Global Ecology and Conservation. 24. doi: 10.1016/j.gecco.2020.e01245. Full text in Research Archive
Lydersen, Espen; Holtan, Marijanne; Korslund, Lars; Raddum, Gunnar; Dolmen, Dag & Wærvågen, Svein Birger [Show all 7 contributors for this article] (2020). Water chemistry, zooplankton and benthos in small lakes within the distribution area of the rare European pool frog Pelophylax lessonae (Camerano) in Norway. VANN. ISSN 0042-2592. 55(1), p. 37–51. Full text in Research Archive Show summary
In June 2018, water chemistry, benthos and zooplankton were investigated in 7 small lakes/ ponds within the key area of the European pool frog Pelophylax lessonae (Camerano) in Norway. The geographic distribution of the Norwegian population is minor, limited to a very few small lakes in the county of Agder in southernmost Norway. Since the species is thermophilic, reproduction success only occurs in warm summers. Accordingly, the pool frog is one of the most rare vertebrates in Norwegian fauna, classified as critically endangered in the Norwegian red list. A breeding program is today established in order to rescue this species.The article deals with potential biotope challenges most relevant for the recruitment success of the pool frog in Norway, primarily related to physical, chemical and biological conditions in surface water. In addition, terrestrial biotope challenges and potential effects of low genetic diversity in the very small Norwegian population are discussed
Pelsmaeker, Nicolas De; Korslund, Lars & Steifetten, Øyvind (2020). Do bank voles (Myodes glareolus) trapped in live and lethal traps show differences in tick burden? PLOS ONE. 15(9), p. 1–14. doi: 10.1371/journal.pone.0239029. Full text in Research Archive Show summary
In studies assessing tick abundance, the use of live traps to capture and euthanize rodent hosts is a commonly used method to determine their burden. However, captive animals can experience debilitating or fatal capture stress as a result prior to collection. An alternative method is the use of lethal traps, but this can potentially lead to tick drop-off between the time of capture and collection. In this study, in order to determine whether subjecting animals to capture stress is inevitable, we tested the difference in sheep tick (Ixodes ricinus) larval burdens between bank voles (Myodes glareolus) captured alive and euthanized, and lethally trapped bank voles. During 2017 and 2018, 1318 bank voles were captured using live (Ugglan Special no. 2) and lethal (Rapp2 Mousetrap) traps during two consecutive years over three seasons in two locations in Norway. Voles captured alive would remain captive until euthanized, while lethally trapped voles were killed instantly upon capture. Log-linear models, accounting for overdispersion, were used to determine whether trap type was influencing observed tick burden. Bank voles captured in lethal traps carried 5.7% more larvae compared to euthanized voles captured in live traps, but this difference was not significant (p = 0.420). Males were overall captured 2.7 times more frequently than females, and the sex ratio was equal in both trap types. This study shows that the use of lethal traps to determine tick burden of rodents is sufficiently reliable, without having to subject animals to potentially lethal stress, hereby reducing some ethical concerns of animal suffering and the results thereof, without compromising accuracy. Lethal trapping is also often more economical and practical, further favoring this collection method.
Kjær, Lene Jung; Klitgaard, Kristine; Soleng, Arnulf; Edgar, Kristin Skarsfjord; Lindstedt, Heidi Elisabeth Heggen & Paulsen, Katrine Mørk [Show all 17 contributors for this article] (2020). Spatial data of Ixodes ricinus instar abundance and nymph pathogen prevalence, Scandinavia, 2016–2017. Scientific Data. 7(1). doi: 10.1038/s41597-020-00579-y. Full text in Research Archive Show summary
Ticks carry pathogens that can cause disease in both animals and humans, and there is a need to monitor the distribution and abundance of ticks and the pathogens they carry to pinpoint potential high risk areas for tick-borne disease transmission. In a joint Scandinavian study, we measured Ixodes ricinus instar abundance at 159 sites in southern Scandinavia in August-September, 2016, and collected 29,440 tick nymphs at 50 of these sites. We additionally measured abundance at 30 sites in August-September, 2017. We tested the 29,440 tick nymphs in pools of 10 in a Fluidigm real-time PCR chip to screen for 17 different tick-associated pathogens, 2 pathogen groups and 3 tick species. We present data on the geolocation, habitat type and instar abundance of the surveyed sites, as well as presence/absence of each pathogen in all analysed pools from the 50 collection sites and individual prevalence for each site. These data can be used alone or in combination with other data for predictive modelling and mapping of high-risk areas.
Kjær, Lene Jung; Soleng, Arnulf; Edgar, Kristin Skarsfjord; Lindstedt, Heidi Elisabeth H; Paulsen, Katrine Mørk & Andreassen, Åshild Kristine [Show all 16 contributors for this article] (2019). A large scale screening for the taiga tick, Ixodes persulcatus, and the meadow tick, Dermacentor reticulatus in southern Scandinavia, 2016. Parasites & Vectors. doi: 10.1186/s13071-019-3596-3. Full text in Research Archive
Kjær, Lene Jung; Soleng, Arnulf; Edgar, Kristin Skarsfjord; Lindstedt, Heidi Elisabeth Heggen; Paulsen, Katrine Mørk & Andreassen, Åshild Kristine [Show all 16 contributors for this article] (2019). Predicting the spatial abundance of Ixodes ricinus ticks in southern Scandinavia using environmental and climatic data. Scientific Reports. 9(1). doi: 10.1038/s41598-019-54496-1. Full text in Research Archive Show summary
Recently, focus on tick-borne diseases has increased as ticks and their pathogens have become widespread and represent a health problem in Europe. Understanding the epidemiology of tick-borne infections requires the ability to predict and map tick abundance. We measured Ixodes ricinus abundance at 159 sites in southern Scandinavia from August-September, 2016. We used field data and environmental variables to develop predictive abundance models using machine learning algorithms, and also tested these models on 2017 data. Larva and nymph abundance models had relatively high predictive power (normalized RMSE from 0.65–0.69, R2 from 0.52–0.58) whereas adult tick models performed poorly (normalized RMSE from 0.94–0.96, R2 from 0.04–0.10). Testing the models on 2017 data produced good results with normalized RMSE values from 0.59–1.13 and R2 from 0.18–0.69. The resulting 2016 maps corresponded well with known tick abundance and distribution in Scandinavia. The models were highly influenced by temperature and vegetation, indicating that climate may be an important driver of I. ricinus distribution and abundance in Scandinavia. Despite varying results, the models predicted abundance in 2017 with high accuracy. The models are a first step towards environmentally driven tick abundance models that can assist in determining risk areas and interpreting human incidence data.
Kjær, Lene Jung; Soleng, Arnulf; Edgar, Kristin Skarsfjord; Lindstedt, Heidi Elisabeth H.; Paulsen, Katrine Mørk & Andreassen, Åshild Kristine [Show all 16 contributors for this article] (2019). Predicting and mapping human risk of exposure to ixodes ricinus nymphs using climatic and environmental data, Denmark, Norway and Sweden, 2016. Eurosurveillance. ISSN 1025-496X. 24(9). doi: 10.2807/1560-7917.ES.2019.24.9.1800101. Full text in Research Archive
Korslund, Lars (2018). Relative efficiency of two models of ugglan special live-traps for capturing small rodents in boreo-nemoral forest. Annales Zoologici Fennici. ISSN 0003-455X. 55(4-6), p. 247–256. doi: 10.5735/086.055.0607. Full text in Research Archive
Milhano, Natacha Alexandra da Fonseca; Korslund, Lars; Evander, Magnus; Ahlm, Clas; Vainio, Kirsti & Dudman, Susanne Gjeruldsen [Show all 7 contributors for this article] (2017). Circulation and diagnostics of Puumala virus in Norway: nephropatia epidemica incidence and rodent population dynamics. APMIS - Journal of Pathologiy, Microbiology and Immunology. ISSN 0903-4641. 125(8), p. 732–742. doi: 10.1111/apm.12712. Full text in Research Archive
Kjelland, Vivian; Rollum, Rikke; Korslund, Lars; Slettan, Audun & Tveitnes, Dag (2015). Borrelia miyamotoi is widespread in Ixodes ricinus ticks in southern Norway. Ticks and Tick-borne Diseases. ISSN 1877-959X. 6(4), p. 516–521. doi: 10.1016/j.ttbdis.2015.04.004. Full text in Research Archive
Flydal, Kjetil; Korslund, Lars; Reimers, Eigil; Johansen, Frode Berntin & Colman, Jonathan Edward (2009). Effects of power lines on area use and behaviour of semi-domestic reindeer in enclosures. International Journal of Ecology. ISSN 1687-9708. 2009. doi: 10.1155/2009/340953. Full text in Research Archive Show summary
We conducted large-scale, replicated experiments to test the effects of two parallel power lines on area use, behaviour, and activity of semidomestic reindeer in enclosures. Yearling female reindeer were released into four 50×400?m enclosures; two treatment enclosures with power lines and two control enclosures. Reindeer from two herds, one from Kautokeino (domestic tame) and one from Vågå, (domestic wild) were tested separately and compared. Individual location within the enclosures was not affected by the power lines. Effects on restless behaviour were ambiguous, with slightly more restless behaviour in the treatment enclosures for the domestic tame reindeer, while the domestic wild reindeer maintained a stable level in the treatment enclosures, increasing with time in the control enclosures. Activity changes were slightly more common among animals within treatment enclosures for both herds, with no indication of habituation during the experiment. The domestic wild reindeer had more than three times the amount of restless behaviour than the domestic tame reindeer. Our study indicates that for reindeer in enclosures, the disturbance from a power line construction is negligible. This suggests that power lines are a minor disturbing factor compared to human handling when using fenced in areas like grazing gardens in reindeer husbandry.
Korslund, Lars (2006). Activity of root voles (Microtus oeconomus) under snow: social encounters synchronize individual activity rhythms. Behavioral Ecology and Sociobiology. ISSN 0340-5443. 61(2), p. 255–263. doi: 10.1007/s00265-006-0256-3. Full text in Research Archive
Korslund, Lars & Steen, Harald (2006). Small rodent winter survival: snow conditions limit access to food resources. Journal of Animal Ecology. ISSN 0021-8790. 75. doi: 10.1111/j.1365-2656.2005.01031. Full text in Research Archive

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Kjelland, Vivian; Korslund, Lars & Slettan, Audun (2014). Fakta om flått. Kagge Forlag AS. ISBN 9788248914143. 126 p. Full text in Research Archive

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Lien, Anne; Larsen, Jorunn; Nygård, Malene Østreng; Gabrielsen, Tove M.; Korslund, Lars & Marcussen, Johanna Bjånes [Show all 10 contributors for this article] (2024). Gimle: En gressplen erstatter ikke skog. p. 15–15. Full text in Research Archive
Lien, Anne; Nygård, Malene Østreng; Laugen, Ane Timenes; Lie, Asbjørn; Slettan, Audun & Johansen, Beate Strøm [Show all 33 contributors for this article] (2023). Utbygging vil ødelegge for biologisk mangfold på campus Gimlemoen. NB! 34 forfattere totalt. p. 19–19. Full text in Research Archive
Larsen, Jorunn; Korslund, Lars & Fiskvatn, Kari (2023). Fortellingen om enda en skog som forsvinner. Full text in Research Archive
Korslund, Lars (2021). Flåtten kryper høyere. [Journal]. Aftenposten (morgenutg. : trykt utg.). Full text in Research Archive
Korslund, Lars (2021). Flåtten kryper høyere. [Journal]. Agderposten. Full text in Research Archive
Korslund, Lars (2021). Flåtten kryper høyere. [Journal]. NTBtekst. Full text in Research Archive
Korslund, Lars (2021). Flåtten kryper høyere. [Journal]. Dagbladet. Full text in Research Archive
Kjær, Lene Jung; Klitgaard, Kirstine; Soleng, Arnulf; Edgar, Kristin Skarsfjord; Lindstedt, Heidi Elisabeth Heggen & Paulsen, Katrine Mørk [Show all 17 contributors for this article] (2020). Author Correction: Spatial data of Ixodes ricinus instar abundance and nymph pathogen prevalence, Scandinavia, 2016–2017 (Scientific Data, (2020), 7, 1, (238), 10.1038/s41597-020-00579-y). Scientific Data. 7(1). doi: 10.1038/s41597-020-00606-y. Full text in Research Archive
Kjær, Lene Jung; Soleng, Arnulf; Edgar, Kristin Skarsfjord; Lindstedt, Heidi Elisabeth H.; Paulsen, Katrine Mørk & Andreassen, Åshild Kristine [Show all 18 contributors for this article] (2019). A large-scale screening for the taiga tick, Ixodes persulcatus, and the meadow tick, Dermacentor reticulatus, in southern Scandinavia, 2016. Parasites & Vectors. 12:338, p. 1–4. doi: 10.1186/s13071-019-3596-3. Full text in Research Archive
Korslund, Lars (2019). Jakter på øl-ingrediens i Setesdal. [Radio]. NRK Sørlandet. Full text in Research Archive
Korslund, Lars (2019). Damfrosken – Norges mest truede dyr. Full text in Research Archive
NRK, Dagsrevyen & Korslund, Lars (2019). Damfrosken skal reddes. [TV]. NRK. Full text in Research Archive
Skår, Kari Løberg & Korslund, Lars (2019). Dette er Norges mest utrydningstruede dyr. [Internet]. NRK.no. Full text in Research Archive
Aas, Tarald Reinholt & Korslund, Lars (2019). Lasten var dyrebar: Mandag ble 25 mer eller mindre voksne damfrosker skysset fra Dyreparken. [Journal]. Agderposten. Full text in Research Archive
Korslund, Lars (2018). Kulden kan gi færre flått i sommer. [Internet]. NRK Nettavis. Full text in Research Archive
Korslund, Lars (2018). Trolig færre flått i år. [Radio]. Nyhetsmorgen NRK P2. Full text in Research Archive
Korslund, Lars (2018). Damfrosk i Agder. Full text in Research Archive
Korslund, Lars & Kjelland, Vivian (2018). Seasonal patterns in questing activity of the sheep tick (Ixodes ricinus) in Scandinavia. Full text in Research Archive
Kjelland, Vivian; Kjelland, Vivian; Korslund, Lars; Edgar, Kristin Skarsfjord; Stuen, Snorre & Slettan, Audun [Show all 9 contributors for this article] (2017). Ixodes ricinus winter survival and spring emergence in southern Norway. Full text in Research Archive
Reimers, Eigil; Flydal, Kjetil; Korslund, Lars; Eftestøl, Sindre; Colman, Jonathan Edward & Alemu, Diress Tsegaye (2015). Power lines, reindeer and UV. Biological Conservation. ISSN 0006-3207. 184, p. 471–471. doi: 10.1016/j.biocon.2014.12.026. Full text in Research Archive
Korslund, Lars (2013). Skaperverket - Skummel som en slange. [TV]. NRK3. Full text in Research Archive Show summary
Er hoggormen Norges farligste skapning eller finnes det noen skapninger som er enda farligere? For å finne svaret møter programleder Ludvig Løkholm Lewin en svært irritert skogens konge og norsk naturs sleipeste snikmorder. I tillegg måler han krefter med Norges største rovdyr og taper.
Korslund, Lars (2013). Lemenår – et fantastisk naturfenomen som kan gå tapt? Full text in Research Archive
Korslund, Lars (2013). Forskningskonferansen - Forskningsdagene ved UiA. Full text in Research Archive
Korslund, Lars (2013). Can microhabitat use explain individual differences in tick parasitism in coexisting small mammal species? Full text in Research Archive
Korslund, Lars (2013). Evolusjonens kunststykker og lappverk - Et blikk fra oss selv fra utsiden. Full text in Research Archive
Korslund, Lars (2013). Lemenår – et fantastisk naturfenomen som kan gå tapt? Full text in Research Archive
Korslund, Lars (2013). Lemenår – et fantastisk naturfenomen som kan gå tapt? Full text in Research Archive
Korslund, Lars (2013). Forskningskonferansen - Forskningsdagene ved UiA. Full text in Research Archive
Korslund, Lars (2012). Lemenår – et fantastisk naturfenomen som kan gå tapt? Full text in Research Archive
Korslund, Lars (2012). Åpen dag ved UiA - Evolusjonens kunststykker og lappverk. Full text in Research Archive
Korslund, Lars (2012). Sørlandssendinga. [Radio]. Intervju - Forskningskonferansen - Forskningsdagene. Full text in Research Archive
Korslund, Lars (2012). Forskningskonferansen - Forskningsdagene ved UiA. Full text in Research Archive
Korslund, Lars (2012). Økologi i naturfag VG1. Full text in Research Archive
Korslund, Lars (2012). Forskningskonferansen - Forskningsdagene ved UiA. Full text in Research Archive
Korslund, Lars (2011). Evolusjonens kunststykker og lappverk. Full text in Research Archive
Korslund, Lars (2011). Can microhabitat use explain individual differences in tick parasitism in coexisting wood mice (Apodemus sylvaticus), bank voles (Myodes glareolus) and common shrews (Sorex araneus)? Full text in Research Archive Show summary
The sheep tick (Ixodes. ricinus) is a major vector of a variety of zoonoses in Europe. This tick species are an ecological generalist, feeding on a variety of hosts. Small mammals are important hosts of juvenile stages (larvae and nymphs) and play an important role in the transmission of such illnesses to humans. Ticks are often heterogeneous distributed between hosts; while some hosts carry no parasites, others carry many. This aggregation of vectors increases the rate of disease spread in a population, and individuals or species hosting large tick burdens therefore play a very important role in the transmission mechanism of tick-borne diseases. Several studies from continental Europe and the Great Britain has shown that the yellow-necked mouse (Apodemus flavicollis) and the wood mouse (A. sylvaticus) carry more ticks than the bank vole (Myodes glareolus), but these studies lack the ability to explain the large interindividual heterogeneity in tick burden across host species. Larvae and nymphs of the sheep tick are vulnerable to high temperatures and low humidity, and their spatial distribution are therefore indirectly governed by vegetation characteristics. The spatial distribution of small mammal hosts are also highly affected by habitat type, and this suggests that the microhabitat use of coexisting small mammals can influence their tick burden. Here I present a study where I test the relationship between individual microhabitat use of small mammals and their tick burden. The study was carried out in a heterogeneous woodland landscape located in Southern Norway. Live trapping of small mammals in high spatial resolution was carried out during four trap sessions throughout 2010. At each trap location, habitat characteristics were examined and abundance of questing ticks were recorded by standard blanket dragging during each of the four trap sessions. Abundance of both host-seeking larva and nymphs were significantly higher in sites where the ground were covered with leaf litter, and where heath of the Vaccinium genus were scarce. There were significant differences in microhabitat use between the small mammal as well; Bank voles were trapped in areas with more leaf litter and more Vaccinium heath than common shrews, while wood mice shoved an intermediate pattern. Contrary to most other studies of tick burden on small mammals, no significant differences in burden between host species could be detected, but males had a significantly higher larval burden than females. However, regardless of sex or species, individuals trapped in sites with much leaf litter (where the highest density of host-seeking tick larva were observed) had a significantly higher larval burden than individuals trapped in sites with minor amounts of leaf litter. These results suggest that the commonly observed heterogeneity in tick burden across host species might be due to individual differences in microhabitat use. The capacity to reduce the spread of tick-borne pathogens rests on the ability to successfully detect individuals that hosts disproportionately large numbers of ticks. This study suggests that individual space use characteristics effect this pattern. Further studies are needed to investigate whether individual microhabitat use and tick burden levels are constant over time or whether they change throughout the season.
Korslund, Lars (2011). Lemenår – et fantastisk naturfenomen som kan gå tapt? Full text in Research Archive
Korslund, Lars (2011). Hva forsker du på? Fædrelandsvennen. ISSN 0805-3790. Full text in Research Archive
Korslund, Lars (2010). Snø, klima og smågnagere. Full text in Research Archive
Korslund, Lars (2001). Abundance of ticks and host over an altitudinal gradient in southern Norway. Full text in Research Archive
Haraldstad, Tormod; Johansen, Kurt; Höglund, Erik & Korslund, Lars (2024). Overvåking av sjøørret i kystvassdrag langs Sørlandskysten. - Utvandringstidspunkt, sjøoverlevelse og livshistoriestrategier. NORCE Research AS. Full text in Research Archive
Bergan, Ingvild; Andreasen, Johan Kristian; Korslund, Lars; Bomark, Nils-Erik; Solgaard, Geir & Elnan, Merete (2018). Rapport – STIL-prosjektet ProDiG Universitetet i Agder. 7Letras. Full text in Research Archive

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Published Apr. 16, 2024 10:58 AM - Last modified Sep. 15, 2026 3:27 PM

Lars Mørch Korslund

Background and experience

I am an ecologist specializing in marine and freshwater systems, with a particular focus on fish ecology, bioacoustics, and telemetry-based approaches.

Areas of responsibility

I currently serve as Deputy Chair of the Centre for Coastal Research (CCR) and Deputy Head of the Department of Natural Sciences.

Teaching

I teach and contribute to several courses at UiA, including:

BIO112 – Introduction to Biology

BIO206 – General Ecology

BIO300 – Bachelor’s Thesis in Biology

BIO413 – Coastal Benthic Ecology

BIO414 – Pelagic Ecology

BIO415 – Study Design, Data Analysis, and Reproducible Science

My teaching emphasizes quantitative skills, inquiry-based learning, ecological understanding, and reproducible science.

I supervise bachelor’s and master’s students every year, usually in connection with my ongoing research projects. Prospective students are very welcome to get in touch if they are interested in a thesis within my research areas.

Research

I primarily study marine and aquatic ecosystems. My work centers on fish ecology and integrates multiple methodological approaches, including passive acoustic monitoring, acoustic telemetry, and genetics.

Bioacoustics and Ecoacoustics

A major part of my research uses Passive Acoustic Monitoring (PAM) to study sound production and communication in fish and, to some extent, amphibians. My research spans both bioacoustics and ecoacoustics and addresses:

Why, how, and when animals use sound

How acoustic communication influences population ecology and evolution

How sound can be used to monitor biodiversity and ecosystem state

The impacts of anthropogenic noise on individuals, populations, and ecosystems

These approaches generate large volumes of data, and I collaborate with colleagues to develop and apply deep learning tools for efficient data processing and analysis.

Salmonids and Coastal Ecosystems

Publications