Svæðisbundin áhrif íslenskra háskóla

Mikill munur er á menntunarstigi þjóðarinnar eftir landshlutum. Árið 2011 höfðu þannig 38% íbúa höfuðborgarsvæðisins á aldrinum 25–64 ára lokið háskólaprófi en 21–23% í flestum öðrum landshlutum. Þessi munur skýrist að hluta af takmörkuðu framboði starfa sem krefjast háskólamenntunar en að hluta af skorti á háskólafólki til starfa. Í þessari rannsókn eru upptökusvæði og áhrif háskóla á búsetuþróun metin á grundvelli gagna um allar brautskráningar frá Háskóla Íslands, Háskólanum á Bifröst, Háskólanum á Hólum og Háskólanum á Akureyri á tímabilinu 1991–2015. Niðurstöður sýna að meirihluti háskólanema sem stunda nám í heimabyggð býr þar áfram eftir brautskráningu en yfirleitt snýr mikill minnihluti háskólanema heim frá háskólanámi utan heimabyggðar. Háskólanemar í fjarnámi eru hins vegar álíka líklegir til að búa áfram í heimabyggð og þeir sem stunda staðarnám við háskóla þar sem þeir eru búsettir. Fjallað er um niðurstöðurnar í samhengi við niðurstöður erlendra rannsókna og byggðaþróun á Íslandi.Peer ReviewedRitrýnd tímari

Multigenerational exposure to elevated temperatures leads to a reduction in standard metabolic rate in the wild

In light of global climate change, there is a pressing need to understand and predict the capacity of populations to respond to rising temperatures. Metabolic rate is a key trait that is likely to influence the ability to cope with climate change. Yet, empirical and theoretical work on metabolic rate responses to temperature changes has so far produced mixed results and conflicting predictions. Our study addresses this issue using a novel approach of comparing fish populations in geothermally warmed lakes and adjacent ambient‐temperature lakes in Iceland. This unique ‘natural experiment' provides repeated and independent examples of populations experiencing contrasting thermal environments for many generations over a small geographic scale, thereby avoiding the confounding factors associated with latitudinal or elevational comparisons. Using Icelandic sticklebacks from three warm and three cold habitats, we measured individual metabolic rates across a range of acclimation temperatures to obtain reaction norms for each population. We found a general pattern for a lower standard metabolic rate in sticklebacks from warm habitats when measured at a common temperature, as predicted by Krogh's rule. Metabolic rate differences between warm‐ and cold‐habitat sticklebacks were more pronounced at more extreme acclimation temperatures, suggesting the release of cryptic genetic variation upon exposure to novel conditions, which can reveal hidden evolutionary potential. We also found a stronger divergence in metabolic rate between thermal habitats in allopatry than sympatry, indicating that gene flow may constrain physiological adaptation when dispersal between warm and cold habitats is possible. In sum, our study suggests that fish may diverge toward a lower standard metabolic rate in a warming world, but this might depend on connectivity and gene flow between different thermal habitats

Patterns, processes, and conservation management consequences of intraspecific diversity, illustrated by fishes from recently glaciated lakes

Patterns in phenotypic and genotypic diversity within many species are becoming increasingly apparent, although there remain many species for which such patterns have yet to be described adequately. Fishes from recently glaciated ecosystems are likely to be particularly rich in intraspecific diversity, yet current conservation management strategies are, in many parts of the world, particularly in Europe, conventionally and overwhelmingly focused on species, regardless of competing species concepts, and appropriate policies for managing diversity at a sub-specific level still have to be developed. Occasional attempts to protect certain vulnerable ecotypes and proposed alternative units of conservation (e.g. ‘Pragmatic Species’ or ‘Evolutionarily Significant Units’) reinforce the conventional primacy of contemporary expressed patterns of variation. Intraspecific phenotypic and genotypic patterns are ultimately the result of complex processes of divergence; conservation approaches that focus on the products of evolution largely ignore the processes that generate and maintain those patterns. Policies that acknowledge the continuation of evolution, the derivation of novel diversity over often very short time spans and the role of environment in initiating and perpetuating these processes are poorly integrated into management strategy. To address possible deficits, where intraspecific diversity is not addressed in management practice, we believe it to be important first to characterize hidden genetic and phenotypic diversity, which may intimate eco-evolutionary processes, initially among species of high conservation status. A second step should be to use an approach to intraspecific diversity that illuminates the ultimate processes and mechanisms that bring about that diversity, which also concedes the central role of the environment and affords adequate protection to the ecosystems that drive these processes, such as the United Nations Convention on Biological Diversity (CBD) Ecosystems approach

What is a fish? The life and legend of David L.G. Noakes

David Lloyd George Noakes (1942–2020) is best known for his insatiable curiosity, his quick wit and dry sense of humor, his scientific contributions to the field of animal behaviour, and his ability to form and maintain long-lasting connections. His research interests were vast but remained grounded in early life history, behaviour, social behaviour, the evolution of behaviour, behavioural genetics, and evolutionary ecology. David had a remarkable ability to establish and maintain strong connections within the international academic community. David was also internationally recognized for his numerous contributions as a scientific editor, promoting accessibility to the international community that he served. We memorialize David’s legacy in this tribute article, ensuring that his accomplishments and the momentous impact he had on the scientific community are not soon forgotten

Geothermal stickleback populations prefer cool water despite multigenerational exposure to a warm environment

Given the threat of climate change to biodiversity, a growing number of studies are investigating the potential for organisms to adapt to rising temperatures. Earlier work has predicted that physiological adaptation to climate change will be accompanied by a shift in temperature preferences, but empirical evidence for this is lacking. Here, we test whether exposure to different thermal environments has led to changes in preferred temperatures in the wild. Our study takes advantage of a “natural experiment” in Iceland, where freshwater populations of threespine sticklebacks (Gasterosteus aculeatus) are found in waters warmed by geothermal activity year-round (warm habitats), adjacent to populations in ambient-temperature lakes (cold habitats). We used a shuttle-box approach to measure temperature preferences of wild-caught sticklebacks from three warm–cold population pairs. Our prediction was that fish from warm habitats would prefer higher water temperatures than those from cold habitats. We found no support for this, as fish from both warm and cold habitats had an average preferred temperature of 13°C. Thus, our results challenge the assumption that there will be a shift in ectotherm temperature preferences in response to climate change. In addition, since warm-habitat fish can persist at relatively high temperatures despite a lower-temperature preference, we suggest that preferred temperature alone may be a poor indicator of a population's adaptive potential to a novel thermal environment

Gene expression in the phenotypically plastic Arctic charr (Salvelinus alpinus): A focus on growth and ossification at early stages of development

Publisher's version (útgefin grein)Gene expression during development shapes the phenotypes of individuals. Although embryonic gene expression can have lasting effects on developmental trajectories, few studies consider the role of maternal effects, such as egg size, on gene expression. Using qPCR, we characterize relative expression of 14 growth and/or skeletal promoting genes across embryonic development in Arctic charr (Salvelinus alpinus). We test to what extent their relative expression is correlated with egg size and size at early life‐stages within the study population. We predict smaller individuals to have higher expression of growth and skeletal promoting genes, due to less maternal resources (i.e., yolk) and prioritization of energy toward ossification. We found expression levels to vary across developmental stages and only three genes (Mmp9, Star, and Sgk1) correlated with individual size at a given developmental stage. Contrary to our hypothesis, expression of Mmp9 and Star showed a non‐linear relationship with size (at post fertilization and hatching, respectively), whilst Sgk1 was higher in larger embryos at hatching. Interestingly, these genes are also associated with craniofacial divergence of Arctic charr morphs. Our results indicate that early life‐stage variation in gene expression, concomitant to maternal effects, can influence developmental plasticity and potentially the evolution of resource polymorphism in fishes.We thank John Postlethwait for his valuable comments on the manuscript. This research was funded by the Icelandic Research Fund, Rannis (grant number 141360 to CAL et al., and grant number 173814–051 to SVB).Peer Reviewe