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"Lundberg, Per"
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Habitat-Selecting Life History
Adaptive life histories emerge through their environmentally dependent effects on fitness. Those effects are consequences of habitat quality and the density-dependent decisions that organisms make on habitat choice. Density dependence for ideal organisms maximizing fitness through habitat selection is uniquely revealed by their habitat isodars, lines in the state space of species’ densities that confer equal fitness between habitats coupled by dispersal. We use isodars to structure simple simulations of habitat selection in stable and stochastic environments. The simulations demonstrate an indirect effect of ideal habitat selection that can dampen otherwise wide fluctuations in abundance and their impact on pace-of-life strategies. The ability of habitat selection to equalize fitness between habitats also has a direct effect on life history evolution. Habitat selection can promote phenotypically plastic life histories between habitats that might otherwise convey divergent genetically fixed strategies. The direct and indirect effects on life history demonstrate that it is not just habitat that requires our concern in managing and conserving nature, but how those activities are likely to impinge on habitat selection.
Journal Article
Mortality in patients with ventricular septal defect in Sweden: a national register study
ObjectivesVentricular septal defect (VSD) is the most common congenital heart defect. Much remains unclear about the long-term prognosis for VSD patients. This study aimed to investigate the all-cause and cardiovascular mortality in patients with VSD compared with controls without congenital heart disease in Sweden.MethodsSwedish National Patient Register was used to identify all VSD patients born between 1970 and 2017. Mortality data were collected from the Swedish National Cause of Death register. Patients with associated complex congenital heart disease or non-congenital VSD were excluded. The VSD cases were matched by age and sex with 10 controls without congenital heart disease for each case.ResultsA total of 22 855 VSD patients were included. The hazard of death for the entire VSD cohort, including patients with syndromes and associated non-complex congenital cardiac lesions, was increased compared with matched controls without congenital heart disease, with a HR of 6.8 (95% CI 6.1 to 7.6) for ages 0–17 years and HR of 3.1 (95% CI 2.5 to 4.0) for ages >18 years, during a mean follow-up of 14.3 years (±11.1). In isolated, non-syndromic VSD, the hazard of death was still elevated compared with controls, regardless of whether the VSD had been repaired in childhood or not. The HR for death for unrepaired VSDs was 4.8 (95% CI 4.1 to 5.6) for ages 0–17 years and 2.1 (95% CI 1.5 to 3.0) for ages >18 years and for VSDs repaired before 18 years of age HR for death was 2.9 (95% CI 1.2 to 7.1) for ages 0–17 years and 8.2 (95% CI 2.2 to 30.4) for ages >18 years.ConclusionsMortality rates were three times higher in adult VSD patients compared with matched controls. Mortality risk was highest in VSD cohorts that included patients with syndromes and congenital valvular lesions, highlighting VSD patients at extra risk of adverse outcomes.
Journal Article
Robust Decision-Making under Severe Uncertainty for Conservation Management
In conservation biology it is necessary to make management decisions for endangered and threatened species under severe uncertainty. Failure to acknowledge and treat uncertainty can lead to poor decisions. To illustrate the importance of considering uncertainty, we reanalyze a decision problem for the Sumatran rhino, Dicerorhinus sumatrensis, using information-gap theory to propagate uncertainties and to rank management options. Rather than requiring information about the extent of parameter uncertainty at the outset, information-gap theory addresses the question of how much uncertainty can be tolerated before our decision would change. It assesses the robustness of decisions in the face of severe uncertainty. We show that different management decisions may result when uncertainty in utilities and probabilities are considered in decision-making problems. We highlight the importance of a full assessment of uncertainty in conservation management decisions to avoid, as much as possible, undesirable outcomes.
Journal Article
Inflammation increases NT-proBNP and the NT-proBNP/BNP ratio
Plasma BNP and NT-proBNP are often regarded as interchangeable parameters in assessing heart failure (HF) severity and prognosis. Renal failure results in disproportionate increases of NT-proBNP and an increased NT-proBNP/BNP ratio. Low kidney function is therefore considered particularly when NT-proBNP is used to assess HF. The purpose of this study was to identify other conditions affecting the NT-proBNP/BNP ratio. We examined the NT-proBNP/BNP ratio, 26 other lab parameters, and clinical factors in 218 patients admitted to the HF ward. In addition to renal function, we also found significant correlations between the NT-proBNP/BNP ratio and inflammation as measured by orosomucoid (r = 0.525, p < 0.0001), CRP (r = 0.333, p < 0.0001), haptoglobulin (r = 0.201, p = 0.02), and alpha1-antitrypsin (r = 0.223, p = 0.01). Reverse correlation was found with transferrin (r = −0.323, p < 0.0001), albumin (r = −0.251, p = 0.003), and S-Fe (r = −0.205, p = 0.02), parameters known to decrease during inflammation. Inflammation increased levels of NT-proBNP more than BNP, resulting in an increased NT-proBNP/BNP ratio. Our findings indicate that NT-proBNP should be evaluated concomitantly with inflammatory status to avoid overestimation of HF severity.
Journal Article
Political Institutions and Their Historical Dynamics
Traditionally, political scientists define political institutions deductively. This approach may prevent from discovery of existing institutions beyond the definitions. Here, a principal component analysis was used for an inductive extraction of dimensions in Polity IV data on the political institutions of all nations in the world the last two centuries. Three dimensions of institutions were revealed: core institutions of democracy, oligarchy, and despotism. We show that, historically and on a world scale, the dominance of the core institutions of despotism has first been replaced by a dominance of the core institutions of oligarchy, which in turn is now being followed by an increasing dominance by the core institutions of democracy. Nations do not take steps from despotic, to oligarchic and then to democratic institutions, however. Rather, nations hosting the core democracy institutions have succeeded in historically avoiding both the core institutions of despotism and those of oligarchy. On the other hand, some nations have not been influenced by any of these dimensions, while new institutional combinations are increasingly influencing others. We show that the extracted institutional dimensions do not correspond to the Polity scores for autocracy, \"anocracy\" and democracy, suggesting that changes in regime types occur at one level, while institutional dynamics work on another. Political regime types in that sense seem \"canalized\", i.e., underlying institutional architectures can and do vary, but to a considerable extent independently of regime types and their transitions. The inductive approach adds to the deductive regime type studies in that it produces results in line with modern studies of cultural evolution and memetic institutionalism in which institutions are the units of observation, not the nations that acts as host for them.
Journal Article
Dispersal, Migration, and Offspring Retention in Saturated Habitats
We examine the evolutionary stability of year‐round residency in territorial populations, where breeding sites are a limiting resource. The model links individual life histories to the population‐wide competition for territories and includes spatial variation in habitat quality as well as a potential parent‐offspring conflict over territory ownership. The general form of the model makes it applicable to the evolution of dispersal, migration, partial migration, and delayed dispersal (offspring retention). We show that migration can be evolutionarily stable only if year‐round residency in a given area would produce a sink population, where mortality exceeds reproduction. If this applies to a fraction of the breeding habitat only, partial migration is expected to evolve. In the context of delayed dispersal, habitat saturation has been argued to form an ecological constraint on independent breeding, which favors offspring retention and cooperative breeding. We show that habitat saturation must be considered as a dynamic outcome of birth, death, and dispersal rates in the population, rather than an externally determined constraint. Although delayed dispersal often associates with intense competition for territories, life‐history traits have direct effects on stable dispersal strategies, which can often override the effect of habitat saturation. As an example, high survival of floaters selects against delayed dispersal, even though it increases the number of competitors for each breeding vacancy (the “habitat saturation factor”). High survival of territory owners, by contrast, generally favors natal philopatry. We also conclude that spatial variation in habitat quality only rarely selects for delayed dispersal. Within a population, however, offspring retention is more likely in high‐quality territories.
Journal Article
Accelerate Synthesis in Ecology and Environmental Sciences
Ecology is a leading discipline in the synthesis of diverse knowledge. Ecologists have had considerable experience in bringing together diverse, multinational data sets, disciplines, and cultural perspectives to address a wide range of issues in basic and applied science. Now is the time to build on this foundation and invest in ecological synthesis through new national or international programs. While synthesis takes place through many mechanisms, including individual efforts, working groups, and research networks, centers are extraordinarily effective institutional settings for advancing synthesis projects.
Journal Article
Principles of niche expansion
Niche expansion is attained by adaptations in two generalized phenotypical traits—niche position and niche width. This gives room for a wide range of conceptual ways of niche filling. The niche variation hypothesis reduces the range by predicting that expansion occurs by increasing variation in niche position, which has been debated on empirical and theoretical grounds as also other options seem possible. Here, we propose a general theory of niche expansion. We review empirical data and show with an eco-evolutionary model how resource diversity and a trade-off in resource acquisition steer niche evolution consistent with observations. We show that the range can be reduced to a discrete set of two orthogonal ways of niche filling, through (1) strict phenotypical differentiation in niche position or (2) strict individual generalization. When individual generalization is costly, niche expansion undergoes a shift from (2) to (1) at a point where the resource diversity becomes sufficiently large. Otherwise, niche expansion always follows (2), consistent with earlier results. We show that this either–or response can operate at both evolutionary and short-term time scales. This reduces the principles of niche expansion under environmental change to a notion of orthogonality, dictated by resource diversity and a resource-acquisition trade-off.
Journal Article