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Diehl, Sebastian
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Publications (10 of 74) Show all publications
Gronchi, E., Straile, D., Diehl, S., Jöhnk, K. D. & Peeters, F. (2023). Impact of climate warming on phenological asynchrony of plankton dynamics across Europe [Letter to the editor]. Ecology Letters, 26(5), 717-728
Open this publication in new window or tab >>Impact of climate warming on phenological asynchrony of plankton dynamics across Europe
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2023 (English)In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 26, no 5, p. 717-728Article in journal, Letter (Refereed) Published
Abstract [en]

Climate warming alters the seasonal timing of biological events. This raises concerns that species-specific responses to warming may de-synchronize co-evolved consumer-resource phenologies, resulting in trophic mismatch and altered ecosystem dynamics. We explored the effects of warming on the synchrony of two events: the onset of the phytoplankton spring bloom and the spring/summer maximum of the grazer Daphnia. Simulation of 16 lake types over 31 years at 1907 North African and European locations under 5 climate scenarios revealed that the current median phenological delay between the two events varies greatly (20–190 days) across lake types and geographic locations. Warming moves both events forward in time and can lengthen or shorten the delay between them by up to ±60 days. Our simulations suggest large geographic and lake-specific variations in phenological synchrony, provide quantitative predictions of its dependence on physical lake properties and geographic location and highlight research needs concerning its ecological consequences.

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
climate change, Daphnia, phenology, phytoplankton, regional modelling
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-205796 (URN)10.1111/ele.14190 (DOI)000943587500001 ()36870064 (PubMedID)2-s2.0-85149523435 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, 2016.0083Swedish Research Council, 2018-04726
Available from: 2023-03-28 Created: 2023-03-28 Last updated: 2023-07-13Bibliographically approved
Diehl, S., Berger, S., Uszko, W. & Stibor, H. (2022). Stoichiometric mismatch causes a warming-induced regime shift in experimental plankton communities. Ecology, Article ID e3674.
Open this publication in new window or tab >>Stoichiometric mismatch causes a warming-induced regime shift in experimental plankton communities
2022 (English)In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, article id e3674Article in journal (Refereed) Published
Abstract [en]

In many ecosystems, consumers respond to warming differently than their resources, sometimes leading to temporal mismatches between seasonal maxima in consumer demand and resource availability. A potentially equally pervasive, but less acknowledged threat to the temporal coherence of consumer-resource interactions is mismatch in food quality. Many plant and algal communities respond to warming with shifts toward more carbon-rich species and growth forms, thereby diluting essential elements in their biomass and intensifying the stoichiometric mismatch with herbivore nutrient requirements. Here we report on a mesocosm experiment on the spring succession of an assembled plankton community in which we manipulated temperature (ambient vs. +3.6°C) and presence versus absence of two types of grazers (ciliates and Daphnia), and where warming caused a dramatic regime shift that coincided with extreme stoichiometric mismatch. At ambient temperatures, a typical spring succession developed, where a moderate bloom of nutritionally adequate phytoplankton was grazed down to a clear-water phase by a developing Daphnia population. While warming accelerated initial Daphnia population growth, it speeded up algal growth rates even more, triggering a massive phytoplankton bloom of poor food quality. Consistent with the predictions of a stoichiometric producer–grazer model, accelerated phytoplankton growth promoted the emergence of an alternative system attractor, where the extremely low phosphorus content of the abundant algal food eventually drove Daphnia to extinction. Where present, ciliates slowed down the phytoplankton bloom and the deterioration of its nutritional value, but this only delayed the regime shift. Eventually, phytoplankton also grew out of grazer control in the presence of ciliates, and the Daphnia population crashed. To our knowledge, the experiment is the first empirical demonstration of the “paradox of energy enrichment” (grazer starvation in an abundance of energy-rich but nutritionally imbalanced food) in a multispecies phytoplankton community. More generally, our results support the notion that warming can exacerbate the stoichiometric mismatch at the plant–herbivore interface and limit energy transfer to higher trophic levels.

Place, publisher, year, edition, pages
Ecological Society of America, 2022
Keywords
alternative states, C:P ratio, Daphnia, ecological stoichiometry, food quality, mesocosm experiment, paradox of energy enrichment, plant-herbivore, temperature, warming
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-124874 (URN)10.1002/ecy.3674 (DOI)000780007500001 ()2-s2.0-85127759512 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, 016.0083Swedish Research Council, 621-2010-5316
Note

Originally included in thesis in manuscript form.

Available from: 2016-08-29 Created: 2016-08-29 Last updated: 2023-09-05Bibliographically approved
Gronchi, E., Jöhnk, K. D., Straile, D., Diehl, S. & Peeters, F. (2021). Local and continental-scale controls of the onset of spring phytoplankton blooms: Conclusions from a proxy-based model. Global Change Biology, 27(9), 1976-1990
Open this publication in new window or tab >>Local and continental-scale controls of the onset of spring phytoplankton blooms: Conclusions from a proxy-based model
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2021 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 27, no 9, p. 1976-1990Article in journal (Refereed) Published
Abstract [en]

A key phenological event in the annual cycle of many pelagic ecosystems is the onset of the spring algal bloom (OAB). Descriptions of the factors controlling the OAB in temperate to polar lakes have been limited to isolated studies of single systems and conceptual models. Here we present a validated modelling approach that, for the first time, enables a quantitative prediction of the OAB and a systematic assessment of the processes controlling its timing on a continental scale. We used a weather-driven, one-dimensional lake model to simulate the seasonal dynamics of the underwater light climate in 16 lake types characterized by the factorial combination of four lake depths with four levels of water transparency. We did so at 1962 locations across Western Europe and over 31 years (1979–2009). Assuming that phytoplankton production is light-limited in winter, we identified four patterns of OAB control across lake types and climate zones. OAB timing is controlled by (i) the timing of ice-off in ice-covered clear or shallow lakes, (ii) the onset of thermal stratification in sufficiently deep and turbid lakes and (iii) the seasonal increase in incident radiation in all other lakes, except for (iv) ice-free, shallow and clear lakes in the south, where phytoplankton is not light-limited. The model predicts that OAB timing should respond to two pervasive environmental changes, global warming and browning, in opposite ways. OAB timing should be highly sensitive to warming in lakes where it is controlled by either ice-off or the onset of stratification, but resilient to warming in lakes where it is controlled by incident radiation. Conversely, OAB timing should be most sensitive to browning where it is controlled by incident radiation, but resilient to browning where it is controlled by ice-off or the onset of stratification. Available lake data are consistent with our findings.

Place, publisher, year, edition, pages
John Wiley & Sons, 2021
Keywords
browning, ice phenology, k-ɛ turbulence model, phenology, phytoplankton, regional modelling, spring bloom, warming
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-181025 (URN)10.1111/gcb.15521 (DOI)000617033300001 ()33459454 (PubMedID)2-s2.0-85101049685 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, 2016.0083Swedish Research Council Formas, 2018-04726
Available from: 2021-03-05 Created: 2021-03-05 Last updated: 2021-07-06Bibliographically approved
Uszko, W., Diehl, S. & Wickman, J. (2020). Fitting functional response surfaces to data: a best practice guide. Ecosphere, 11(4), Article ID e03051.
Open this publication in new window or tab >>Fitting functional response surfaces to data: a best practice guide
2020 (English)In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 11, no 4, article id e03051Article in journal (Refereed) Published
Abstract [en]

Describing how resource consumption rates depend on resource density, conventionally termed "functional responses," is crucial to understanding the population dynamics of trophically interacting organisms. Yet, accurately determining the functional response for any given pair of predator and prey remains a challenge. Moreover, functional responses are potentially complex surfaces in multidimensional space, where resource density is only one of several factors determining consumption rates. We explored how three sources of error can be addressed in the design and statistical analysis of functional response experiments: ill-chosen spacing of prey densities, heteroscedastic variance in consumption rates, and non-independence of parameters of the function describing prey consumption in relation to prey density and additional environmental factors. We generated extensive, virtual data sets that simulated feeding experiments in which both prey density and environmental temperature were varied, and for which the true, deterministic functional response surface was known and realistic variance had been added. We compared eight different methods of functional response fitting, one of which stood out as best performing. We subsequently tested several conclusions from the simulation study against experimental data of zooplankton feeding on algae across a broad range of temperatures. We summarize our main findings in three best practice guidelines for the experimental estimation of functional response surfaces, of which the second is the most important: (1) space prey densities logarithmically, starting from very low densities; (2) log-transform prey consumption data prior to fitting; and (3) fit a multivariate functional response surface to all data (including all prey densities and other factors, in our case temperature) in a single step. We also observed that functional response surfaces were fitted more accurately and precisely than their component parameters. The latter occurred because parameter estimates were non-independent, which is an inevitable feature of fitting complex nonlinear functions to data: A given response surface can often be described with near-equal accuracy by multiple parameter combinations. We therefore conclude that fitted functional response models perform better at optimizing the fit of the overall response surface than at determining how component parameters, such as the attack rate or handling time, depend on environmental factors such as temperature.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2020
Keywords
data transformation, functional response, heteroscedasticity, Hill exponent, ingestion rate, parameter correlation, parameter estimation, prey density, temperature, type III
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-172511 (URN)10.1002/ecs2.3051 (DOI)000536583400024 ()2-s2.0-85084508099 (Scopus ID)
Funder
Swedish Research Council, 621-2010-5316
Available from: 2020-07-02 Created: 2020-07-02 Last updated: 2020-07-02Bibliographically approved
Vasconcelos, F. R., Diehl, S., Rodríguez, P., Hedström, P., Karlsson, J. & Byström, P. (2019). Bottom-up and top-down effects of browning and warming on shallow lake food webs. Global Change Biology, 25, 504-521
Open this publication in new window or tab >>Bottom-up and top-down effects of browning and warming on shallow lake food webs
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2019 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 25, p. 504-521Article in journal (Refereed) Published
Abstract [en]

The productivity and trophic structure of aquatic ecosystems is the result of an interplay between bottom-up and top-down forces that operate both within and across the benthic and pelagic compartments of lake food webs. Contemporary and projected climate changes urge the question how this interplay will be affected by increasing inputs of terrestrial derived, dissolved organic matter (‘browning’) and warming. We addressed this issue by exploring how browning and warming affect the behavior of a relatively simple, conceptual model of a shallow lake food web that is compartmentalized into, dynamically coupled, benthic and pelagic components (abiotic resources, primary producers, grazers, and carnivores). We compared model expectations with the results of a factorial manipulation of browning and warming in a replicated, large-scale field experiment. Both the model and the experiment suggest that browning affects the food web from the bottom-up by reducing light supply to the benthic habitat and increasing nutrient supply to the pelagic habitat, with concomitant decreases of benthic and increases of pelagic primary and secondary production. The model also predicts that warming effects should primarily operate via relaxed top-down control by top consumers in the more productive of the two habitats. The latter was only partially supported by the experimental data, possibly because the model still lacks one or two important trophic links, such as the one from pelagic producers to benthic deposit feeders. We propose that our coupled benthic-pelagic food web model provides a useful conceptual starting point for future theoretical and empirical studies of the impacts of environmental changes on shallow lakes.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
benthic and pelagic habitats, bottom-up and top-down control, browning, food webs, light and nutrients, shallow lake, top predator, warming
National Category
Ecology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-133326 (URN)10.1111/gcb.14521 (DOI)000456028900011 ()30430702 (PubMedID)2-s2.0-85058481248 (Scopus ID)
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council, 621-2011-3908Swedish Research Council, 621-2014-5238Ecosystem dynamics in the Baltic Sea in a changing climate perspective - ECOCHANGEThe Kempe Foundations
Note

Originally included in thesis in manuscript form.

Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2023-03-24Bibliographically approved
Wickman, J., Diehl, S. & Brännström, Å. (2019). Evolution of resource specialisation in competitive metacommunities [Letter to the editor]. Ecology Letters, 22(11), 1746-1756
Open this publication in new window or tab >>Evolution of resource specialisation in competitive metacommunities
2019 (English)In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 22, no 11, p. 1746-1756Article in journal, Letter (Refereed) Published
Abstract [en]

Spatial environmental heterogeneity coupled with dispersal can promote ecological persistence of diverse metacommunities. Does this premise hold when metacommunities evolve? Using a two-resource competition model, we studied the evolution of resource-uptake specialisation as a function of resource type (substitutable to essential) and shape of the trade-off between resource uptake affinities (generalist- to specialist-favouring). In spatially homogeneous environments, evolutionarily stable coexistence of consumers is only possible for sufficiently substitutable resources and specialist-favouring trade-offs. Remarkably, these same conditions yield comparatively low diversity in heterogeneous environments, because they promote sympatric evolution of two opposite resource specialists that, together, monopolise the two resources everywhere. Consumer diversity is instead maximised for intermediate trade-offs and clearly substitutable or clearly essential resources, where evolved metacommunities are characterised by contrasting selection regimes. Taken together, our results present new insights into resource-competition-mediated evolutionarily stable diversity in homogeneous and heterogeneous environments, which should be applicable to a wide range of systems.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
Adaptive dynamics, coexistence, consumer-resource interactions, ESS, spatial models
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-162861 (URN)10.1111/ele.13338 (DOI)000480204800001 ()31389134 (PubMedID)2-s2.0-85070487188 (Scopus ID)
Available from: 2019-09-06 Created: 2019-09-06 Last updated: 2023-03-24Bibliographically approved
Maier, D. B., Diehl, S. & Bigler, C. (2019). Interannual variation in seasonal diatom sedimentation reveals the importance of late winter processes and their timing for sediment signal formation. Limnology and Oceanography, 64(3), 1186-1199
Open this publication in new window or tab >>Interannual variation in seasonal diatom sedimentation reveals the importance of late winter processes and their timing for sediment signal formation
2019 (English)In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 64, no 3, p. 1186-1199Article in journal (Refereed) Published
Abstract [en]

Disentangling the process information contained in a diatom sediment signature is crucial for reliable future predictions based on paleolimnological records. In this study, we combine limnological and paleolimnological monitoring to address the fundamental question: Which environmental information is contained in a diatom sediment signal? We compared annual diatom sequential sediment trap records with the diatom record of the annually varved lake sediment of Nylandssjon (northern Sweden) from three meteorologically different years (2012-2014). The seasonal patterns in diatom sedimentation were strikingly different in varve years 2012 and 2014 compared to varve year 2013. In 2012 and 2014, up to 70% of the annual flux occurred in a single spring month and was dominated by Cyclotella glomerata. In contrast, in 2013, peak fluxes were much lower and more annually integrated. Next, we compared the full-year diatom trap results with year round in-lake physical, chemical, and biological monitored parameters, as well as meteorological variables. Annual averages of environmental conditions did not explain the interannual variability in diatom sedimentation. Instead, the seasonality of diatom sedimentation was determined by the timing of the spring diatom bloom relative to lake over-turn in winters with warm vs. cold air temperature. With our combined limnological and paleolimnological monitoring approach, we find that an annual diatom signal can either contain primarily seasonal climate information from a short time period or be annually integrated. We synthesize our results in a novel conceptual model, which describes the response of sediment diatom signals to two distinct sequences of late-winter conditions.

Place, publisher, year, edition, pages
Association for the Science of Limnology and Oceanography, 2019
National Category
Geology Climate Research
Identifiers
urn:nbn:se:umu:diva-159614 (URN)10.1002/lno.11106 (DOI)000467593600022 ()2-s2.0-85065469146 (Scopus ID)
Available from: 2019-06-17 Created: 2019-06-17 Last updated: 2023-03-24Bibliographically approved
Vasconcelos, R. F., Diehl, S., Rodríguez, P., Karlsson, J. & Byström, P. (2018). Effects of Terrestrial Organic Matter on Aquatic Primary Production as Mediated by Pelagic-Benthic Resource Fluxes. Ecosystems (New York. Print), 21(6), 1255-1268
Open this publication in new window or tab >>Effects of Terrestrial Organic Matter on Aquatic Primary Production as Mediated by Pelagic-Benthic Resource Fluxes
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2018 (English)In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 21, no 6, p. 1255-1268Article in journal (Refereed) Published
Abstract [en]

Flows of energy and matter across habitat boundaries can be major determinants of the functioning of recipient ecosystems. It is currently debated whether terrestrial dissolved organic matter (tDOM) is a resource subsidy or a resource subtraction in recipient lakes. We present data from a long-term field experiment in which pelagic phosphorus concentration and whole-ecosystem primary production increased with increasing tDOM input, suggesting that tDOM acted primarily as a direct nutrient subsidy. Piecewise structural equation modeling supports, however, a substantial contribution of a second mechanism: colored tDOM acted also as a resource subtraction by shading benthic algae, preventing them from intercepting nutrients released across the sediment-water interface. Inhibition of benthic algae by colored tDOM thus indirectly promoted pelagic algae and whole-ecosystem primary production. We conclude that cross-ecosystem terrestrial DOM inputs can modify light and nutrient flows between aquatic habitats and alter the relative contributions of benthic and pelagic habitats to total primary production. These results are particularly relevant for shallow northern lakes, which are projected to receive increased tDOM runoff.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
spatial subsidy, allochthonous input, dissolved organic matter, resource competition, nutrients, light, pelagic, benthic, warming, brownification, piecewise SEM
National Category
Ecology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-152268 (URN)10.1007/s10021-017-0217-x (DOI)000444384400013 ()2-s2.0-85040653355 (Scopus ID)
Funder
Knut and Alice Wallenberg FoundationThe Kempe FoundationsSwedish Research Council, 621-2011-3908Swedish Research Council, 621-2014-5238
Available from: 2018-10-02 Created: 2018-10-02 Last updated: 2023-03-24Bibliographically approved
Diehl, S., Thomsson, G., Kahlert, M., Guo, J., Karlsson, J. & Liess, A. (2018). Inverse relationship of epilithic algae and pelagic phosphorus in unproductive lakes: Roles of N-2 fixers and light. Freshwater Biology, 63(7), 662-675
Open this publication in new window or tab >>Inverse relationship of epilithic algae and pelagic phosphorus in unproductive lakes: Roles of N-2 fixers and light
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2018 (English)In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 63, no 7, p. 662-675Article in journal (Refereed) Published
Abstract [en]

Phosphorus (P) often limits the biomass of primary producers in freshwater lakes. However, in unproductive northern lakes, where anthropogenic nitrogen (N) deposition is low, N instead of P can limit primary producers. In addition, light can be limiting to primary producers at high concentrations of coloured dissolved organic matter (cDOM), as cDOM is the major determinant of light penetration in these lakes.

To address resource limitation of epilithic algal biomass, we repeatedly sampled epilithon (periphyton on stony substrata) in 20 lakes covering a large, correlated cDOM and N‐deposition gradient across boreal and subarctic Sweden. Across these lakes, pelagic total N (TN) and total P (TP) were positively correlated, and benthic light supply was negatively correlated, with cDOM. Microscopically determined algal biovolume and epilithic carbon (C), N and P were subsequently regressed against benthic light supply and pelagic TN and TP.

Patterns in epilithic biovolume were driven by N2‐fixing cyanobacteria, which accounted for 2%–90% of total epilithic biovolume. Averaged over the growing season, epilithic algal biovolume, C and N were negatively related to TP and positively to TN, and were highest in the clearest, most phosphorus‐poor lakes, where epilithon was heavily dominated by potentially N2‐fixing cyanobacteria.

A structural equation model supports the hypothesis that cDOM had two counteracting effects on total epilithic algal biovolume: a positive one by providing N to algae that depend on dissolved N for growth, and a negative one by shading N2‐fixing cyanobacteria, with the negative effect being somewhat stronger.

Together, these findings suggest that (1) light and N are the main resources limiting epilithic algal biomass in boreal to subarctic Swedish lakes, (2) epilithic cyanobacteria are more competitive in high‐light and low‐nitrogen environments, where their N2‐fixing ability allows them to reach high biomass, and (3) epilithic N increases with N2 fixer biomass and is—seemingly paradoxically—highest in the most oligotrophic lakes.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
dissolved organic matter, light, nitrogen-fixing cyanobacteria, nutrients, periphyton
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-150170 (URN)10.1111/fwb.13103 (DOI)000434110200005 ()2-s2.0-85044620431 (Scopus ID)
Funder
Swedish Research Council, 621-2014-5238Swedish Research Council Formas
Available from: 2018-07-18 Created: 2018-07-18 Last updated: 2023-03-24Bibliographically approved
Wickman, J., Diehl, S., Blasius, B., Klausmeier, C. A., Ryabov, A. B. & Brännström, Å. (2017). Determining Selection across Heterogeneous Landscapes: A Perturbation-Based Method and Its Application to Modeling Evolution in Space. American Naturalist, 189(4), 381-395
Open this publication in new window or tab >>Determining Selection across Heterogeneous Landscapes: A Perturbation-Based Method and Its Application to Modeling Evolution in Space
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2017 (English)In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 189, no 4, p. 381-395Article in journal (Refereed) Published
Abstract [en]

Spatial structure can decisively influence the way evolutionary processes unfold. To date, several methods have been used to study evolution in spatial systems, including population genetics, quantitative genetics, moment-closure approximations, and individual-based models. Here we extend the study of spatial evolutionary dynamics to eco-evolutionary models based on reaction-diffusion equations and adaptive dynamics. Specifically, we derive expressions for the strength of directional and stabilizing/disruptive selection that apply both in continuous space and to metacommunities with symmetrical dispersal between patches. For directional selection on a quantitative trait, this yields a way to integrate local directional selection across space and determine whether the trait value will increase or decrease. The robustness of this prediction is validated against quantitative genetics. For stabilizing/disruptive selection, we show that spatial heterogeneity always contributes to disruptive selection and hence always promotes evolutionary branching. The expression for directional selection is numerically very efficient and hence lends itself to simulation studies of evolutionary community assembly. We illustrate the application and utility of the expressions for this purpose with two examples of the evolution of resource utilization. Finally, we outline the domain of applicability of reaction-diffusion equations as a modeling framework and discuss their limitations.

Place, publisher, year, edition, pages
UNIV CHICAGO PRESS, 2017
Keywords
evolution, spatial, reaction-diffusion models, adaptive dynamics, quantitative genetics, metacommunities
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:umu:diva-134209 (URN)10.1086/690908 (DOI)000398685600006 ()28350499 (PubMedID)2-s2.0-85016447959 (Scopus ID)
Available from: 2017-06-20 Created: 2017-06-20 Last updated: 2023-03-23Bibliographically approved
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