Johan Hollander

Johan Hollander
World Maritime University | WMU

Professor

About

61
Publications
11,422
Reads
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1,759
Citations
Additional affiliations
January 2010 - November 2015
Lund University
Position
  • Researcher Marine Biology
January 2008 - December 2010
The University of Sheffield
Position
  • PostDoc Position
January 2001 - December 2006
Marine Biological Laboratory
Position
  • PhD Student

Publications

Publications (61)
Article
Full-text available
Coastal protection has evolved from focusing on hard solutions such as breakwaters and groynes to include soft or nature‐based solutions (NbS). NbS have been proposed as cost‐effective means to offer long‐term coastal protection and at the same time strengthen coastal resilience and biodiversity. However, projects utilizing NbS for coastal protecti...
Article
Climate change and anthropogenic activities are producing a range of new selection pressures, both abiotic and biotic, on marine organisms. Although it is known that climate change can differentially affect fitness‐related traits at different trophic levels of the food web, it is not clear if different trophic levels will respond via phenotypic pla...
Article
Full-text available
Marine ecosystems are currently facing a variety of anthropogenic perturbations, including climate change. Trophic differences in response to climate change may disrupt ecological interactions and thereby threaten marine ecosystem function. Yet, we still do not have a comprehensive understanding of how different trophic levels respond to climate ch...
Article
Along with a steady increasing use of artificial nitrogen fertilizer, concerns have been raised about the effects that high nitrogen loading may have on ecosystems. Due to the toxicity of unionized ammonia (NH 3), tolerance criteria have been proposed for ambient water management in many countries; however, these are mainly based on acute or chroni...
Article
The Caribbean region is home to some of the world’s most biologically diverse marine resources, which inhabitants rely on for food and economic sustainability. To facilitate the management and conservation of these resources, international and regional fishery bodies have offered capacity building assistance to Caribbean countries, toward full impl...
Article
Full-text available
Seagrass meadows are one of the most important habitats in coastal regions since they constitute a multifunctional ecosystem providing high productivity and biodiversity. They play a key role in carbon sequestration capacity, mitigation against coastal erosion and as nursery grounds for many marine fish and invertebrates. However, despite these eco...
Article
Full-text available
There is widespread consensus among climate scientists today that global climate change is real and has anthropogenic roots. Marine species, for example, are exposed to a large array of abiotic stressors, such as warming and ocean acidification, that are linked directly to anthropogenic climate change. The general view on whether natural population...
Article
Full-text available
The flat periwinkles, Littorina fabalis and L. obtusata, comprise two sister gastropod species that have an enormous potential to elucidate the mechanisms involved in ecological speciation in the marine realm. However, the molecular resources currently available for these species are still scarce. In order to circumvent this limitation, we used RNA...
Article
Full-text available
Abstract Characterizing the patterns of hybridization between closely related species is crucial to understand the role of gene flow in speciation. In particular, systems comprising multiple contacts between sister species offer an outstanding opportunity to investigate how reproductive isolation varies with environmental conditions, demography and...
Article
Alarming amounts of microplastics have recently been shown to accumulate in the environment. Recent focus has been on synthetic material contaminating the marine environment, while effects on freshwater habitats and organisms have received less attention. We here confirm and analyse occurrence of microplastics in the duck mussel, Anodonta anatina,...
Article
Full-text available
The evolution of assortative mating is a key part of the speciation process. Stronger assortment, or greater divergence in mating traits, between species pairs with overlapping ranges is commonly observed, but possible causes of this pattern of reproductive character displacement are difficult to distinguish. We use a multidisciplinary approach to...
Data
Figure S6. Posterior distributions of the NM model parameters.
Data
Table S1. Collection sites of Littoraria cingulata and L. filosa. Table S2. Analysis of individual penis traits (after size correction). Table S3. Uniform prior distributions [low bound – high bound], after having ensured that priors included the posteriors. Table S4. Parameter estimation under the NM model, chosen for having received the highes...
Data
Figure S4. Posterior probabilities of models NM and RM over 100 rounds of leave‐one‐out cross‐validation analysis.
Data
Figure S1. Feature extraction from penis drawings (see Supplementary Methods for details).
Data
Figure S2. Demographic models investigated in this study.
Data
Figure S5. Principal component analysis of datasets simulated under models NM and RM (1e6 datasets under each model) using the a priori simulated summary statistics.
Article
Full-text available
Numerous prey organisms, including many rotifers, exhibit inducible defensive plasticity, such as spines, in response to predators. Here, we test the hypothesis that prey modify their defence response to different predator sizes with a bi-directional adjustment in spine length. First, we show experimentally, that large-sized predators induce a redu...
Article
Full-text available
It is rare to encounter a scientific fact that stirs widespread debate and distrust quite like the matter of climate change. Despite consensus among climate specialists about a theory that is supported by a mountain of facts from the physical, natural, and cultural sciences, the debate continues to be perpetrated by politicians, industrialists, aca...
Article
The need for sustainable agricultural systems, which for example enhance soil organic carbon (SOC) content, has increased the interest for management with reduced tillage. In this study we used a Swedish long-term (20 yrs.) systems experiment, including reduced tillage (harrowing 10 cm) and plowing (moldboard plow 0–20 cm) combined with three level...
Article
Full-text available
The evolution of phenotypic plasticity requires a number of conditions. Selection of plasticity is favoured when the organism experience environmental change, costs are low and cues are reliable about the environmental heterogeneity. However, organisms living in stable environments, not showing constitutive traits but a large amount of plasticity,...
Article
Full-text available
Non-significant results are less likely to be reported by authors and, when submitted for peer review, are less likely to be published by journal editors. This phenomenon, known collectively as publication bias, is seen in a variety of scientific disciplines and can erode public trust in the scientific method and the validity of scientific theories...
Article
Full-text available
A central question in evolutionary biology is how coevolutionary history between predator and prey influences their interactions. Contemporary global change and range expansion of exotic organisms impose a great challenge for prey species, which are increasingly exposed to invading non-native predators,with which they share no evolutionary history....
Article
Full-text available
Extreme climatic events, such as heat waves, are predicted to increase in frequency and intensity during the next hundred years, which may accelerate shifts in hydrological regimes and submerged macrophyte composition in freshwater ecosystems. Since macrophytes are profound components of aquatic systems, predicting their response to extreme climati...
Article
Full-text available
An official journal of the Genetics Society, Heredity publishes high-quality articles describing original research and theoretical insights in all areas of genetics. Research papers are complimented by News & Commentary articles and reviews, keeping researchers and students abreast of hot topics in the field.
Article
Full-text available
There have been few attempts to synthesise the growing body of literature on phenotypic plasticity to reveal patterns and generalities about the extent and magnitude of plastic responses. Here, we conduct a review and meta-analysis of published literature on phenotypic plasticity in aquatic (marine and freshwater) gastropods, a common system for st...
Presentation
Full-text available
Natural selection can strengthen the reproductive isolation between two divergent lineages that come into secondary contact, a process known as reinforcement. However, how often this process contributes to speciation is still poorly understood. In many cases, reinforcement can produce stronger assortative mating in areas where the two lineages over...
Presentation
Full-text available
Natural selection can strengthen the reproductive isolation between two divergent lineages that come into secondary contact, a process known as reinforcement. However, how often this process contributes to speciation is still poorly understood. In many cases, reinforcement can produce stronger assortative mating in areas where the two lineages over...
Article
Full-text available
Since 2006, the Pacific oyster Crassostrea gigas has been a permanent resident on the west cost of Sweden. Because C. gigas is nonindigenous in Scandinavia, it may modify ecosystems and affect the resident biota. Individuals of C. gigas often settle in large aggregations, and the physical structure of the resulting reef provides attachment points a...
Article
A fundamental issue in speciation research is to evaluate phenotypic variation and the genomics driving the evolution of reproductive isolation between sister taxa. Above all, hybrid zones are excellent study systems for researchers to examine the association of genetic differentiation, phenotypic variation and the strength of selection. We investi...
Article
Full-text available
Organisms display an impressive array of defence strategies in nature. Inducible defences (changes in morphology and/or behaviour within a prey's lifetime) allow prey to decrease vulnerability to predators and avoid unnecessary costs of expression. Many studies report considerable interindividual variation in the degree to which inducible defences...
Data
Full-text available
Haplotype networks derived from mtDNA and nuclear sequence data.
Data
Logistic regressions for model validation.
Data
Summary statistics for all datasets, as used in the ABC analyses.
Data
Parameter estimates from the ABC models.
Data
Full-text available
Posterior quantile analyses used in model checking.
Article
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Parallel evolution of similar phenotypes provides strong evidence for the operation of natural selection. Where these phenotypes contribute to reproductive isolation, they further support a role for divergent, habitat-associated selection in speciation. However, the observation of pairs of divergent ecotypes currently occupying contrasting habitats...
Article
Full-text available
A pattern of greater divergence in mating traits between sister-species pairs with overlapping ranges than between allopatric species pairs is expected if reinforcement commonly contributes to speciation. Few large-scale comparative analyses have addressed this prediction, especially for genital form. Here, we show that penial morphology follows th...
Article
Full-text available
In addition to having constitutive defence traits, many organisms also respond to predation by phenotypic plasticity. In order for plasticity to be adaptive, induced defences should incur a benefit to the organism in, for example, decreased risk of predation. However, the production of defence traits may include costs in fitness components such as...
Data
Further details of the principal components analysis. (XLS)
Article
Full-text available
The expression of anti-predator adaptations may vary on a spatial scale, favouring traits that are advantageous in a given predation regime. Besides, evolution of different developmental strategies depends to a large extent on the grain of the environment and may result in locally canalized adaptations or, alternatively, the evolution of phenotypic...
Chapter
Full-text available
Biological invasions offer fertile grounds for studying evolutionary ecology because species’ contact histories are uncharacteristically well-defined. As a result, invasions can be used to gain glimpses of the earliest micro-evolutionary responses of natural populations to new species’ interactions by studying changes in behaviour, physiology or mo...
Data
Shape variables. Shape variables and categorical response variables assessed to describe variation in shell shape among surviving and non-surviving individuals from the two ecotypes and three different laboratory environmental treatments.
Article
Full-text available
Few surveys have concentrated on studying the adaptive value of phenotypic plasticity within genetically-distinct conspecific ecotypes. Here, we conduct a test to assess the adaptive value that partial phenotypic plasticity may have for survival in the marine gastropod Littorina saxatilis. This species has evolved canalized ecotypes but, neverthele...
Article
Formation of partially reproductively isolated ecotypes in the rough periwinkle, Littorina saxatilis, may be a case of incipient nonallopatric ecological speciation. To better understand the dynamics of ecotype formation, its timescale, driving forces and evolutionary consequences, we developed a spatially explicit, individual-based model incorpora...
Article
Some mitochondrial introgression is common between closely related species, but distinct species rarely show substantial introgression in their entire distribution range. In this study, however, we report a complete lack of mitochondrial divergence between two sympatric species of flat periwinkles (Littorina fabalis and Littorina obtusata) which, b...
Article
Full-text available
Corticosterone exposure during prenatal development as a result of maternal upregulation of circulating hormone levels has been shown to have effects on offspring development in mammals. Corticosterone has also been documented in egg yolk in oviparous vertebrates, but the extent to which this influences phenotypic development is less studied. We sh...
Article
Recent research has shown the potential for nonallopatric speciation, but we lack an adequate understanding of the mechanisms of prezygotic barriers and how these evolve in the presence of gene flow. The marine snail Littorina saxatilis has distinct ecotypes in different shore microhabitats. Ecotypes hybridize in contact zones, but gene flow is imp...
Article
Two ecotypes of a marine intertidal snail (Littorina saxatilis), living at different microhabitats and shore levels, have evolved in sympatry and in parallel across the Galician rocky shore. These ecotypes differ in many traits (including size) due to differential adaptation. They meet, mate assortatively, and partially hybridize at the mid shore w...
Article
Phenotypic plasticity is the ability of a genotype to modify its phenotypic characteristics in response to different environments. Theory predicts that adaptive plasticity should primarily evolve in organisms that experience heterogeneous environments. An organism's dispersal rate is a key component in these models, because the degree of dispersal...
Article
Variation in ontogenetic development among individuals may be a major contributor to morphological variation within species. Evolution of different growth trajectories might, for example, evolve as a response to varying ecological contexts of individuals living in different environments, or by life-stage or gender differences. The intertidal periwi...
Article
The evolution of reproductive isolation in the presence of gene flow is supported by theoretical models but rarely by data. Empirical support might be gained from studies of parallel hybrid zones between interbreeding taxa. We analysed gene flow over two hybrid zones separating ecotypes of Littorina saxatilis to test the expectation that neutral ge...
Article
In organisms encountering predictable environments, fixed development is expected, whereas in organisms that cannot predict their future environment, phenotypic plasticity would be optimal to increase local adaptation. To test this prediction we experimentally compared phenotypic plasticity in two rocky-shore snail species; Littorina saxatilis rele...
Article
A crucial assumption in models of ecological speciation is that reproductive barriers evolve as a consequence of ecological divergence of populations, rather than geographical separation. To test the prediction that barriers between populations might evolve in the face of gene flow, we studied reproductive barriers between populations of two Swedis...

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Projects

Projects (5)
Project
Global climate change is contributing to elevated sea levels and storm surges, leading to increased coastal erosion and flooding. This accelerating trend has profound effects on urban and rural coastal areas. Infrastructure and flood defense systems have been instigated, often using hard structures such as groins and seawalls. However, hard structures may cause or contribute to shifting erosion alongshore and eventually converting sandy beaches and dune landscapes into rock and concrete coasts. Loss of sandy beaches means loss of valuable ecosystems and their ecosystem services for coastal inhabitants. Previous actions have not yet fully explored the efficiency, sustainability, and stakeholder acceptance of ecosystem-based protection measures also known as green infrastructure, such as beach nourishment and eelgrass meadow restoration. With these coastal ecosystem-based adaptations, we can reduce the negative impacts of coastal erosion, while at the same time facilitating an improvement in biodiversity and ecosystem services on land and sea. These new insights make research on green infrastructure and “building with nature” more exciting than ever.
Project
We are studying the formation and evolution of reproductive barriers, which prevent or restrict gene flow between populations, eventually leading to the formation of species. Pairs of sister species with some overlapping populations, likely resulting from secondary contact, offer an excellent opportunity in which we can study this process. In such scenarios, a pattern of greater differentiation in reproductive traits could be observed if the crossing between the two species produces unfit or inviable offspring. However, this pattern of reproductive character displacement can result in the face of gene flow (reinforcement) or without gene flow (reproductive interference). We are testing these possibilities in a sister-species pair of sea snails of the genus Littoraria from Australia to better understand the role that natural selection might be playing in the formation of species by reinforcing the reproductive isolation between species that still exchange genes.
Project
We ask the question, if and how, large political events may have influenced the climate change science. We are also interested in extreme climatic events as well as invasive species and how they may influence aquatic organisms and ecosystems.