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Säterberg, T., Jonsson, T., Yearsley, J., Berg, S. & Ebenman, B. (2019). A potential role for rare species in ecosystem dynamics. Scientific Reports, 9, 1-12, Article ID 11107.
Open this publication in new window or tab >>A potential role for rare species in ecosystem dynamics
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2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, p. 1-12, article id 11107Article in journal (Refereed) Published
Abstract [en]

The ecological importance of common species for many ecosystem processes and functions is unquestionably due to their high a bundance.Yet, the importance of rare species is much less understood. Here we take a theoretical approach, exposing dynamical models of ecological networks to small perturbations, to explore the dynamical importance of rare and common species. We find that both species types contribute to the recovery of communities following generic perturbations (i.e. perturbations affecting all species).Yet, when perturbations are selective (i.e. affects only one species), perturbations to rare species have the most pronounced effect on community stability. We show that this is due to the strong indirect effects induced by perturbations to rare species. Because indirect effects typically set in at longer timescales, our results indicate that the importance of rare species may be easily overlooked and thus underrated. Hence, our study provides a potential ecological motive for the management and protection of rare species.

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
Keywords
ecological interactions, interaction strengths, food, diversity, perturbations, extinctions, complexity, stability
National Category
Ecology
Research subject
Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-17533 (URN)10.1038/s41598-019-47541-6 (DOI)000477950800030 ()31366907 (PubMedID)eid=2-s2.0-85070937056 (Scopus ID)
Available from: 2019-08-15 Created: 2019-08-15 Last updated: 2019-09-04Bibliographically approved
Curtsdotter, A., Banks, H. T., Banks, J. E., Jonsson, M., Jonsson, T., Laubmeier, A. N., . . . Bommarco, R. (2019). Ecosystem function in predator-prey food webs: confronting dynamic models with empirical data. Journal of Animal Ecology, 88(2), 196-210
Open this publication in new window or tab >>Ecosystem function in predator-prey food webs: confronting dynamic models with empirical data
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2019 (English)In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 88, no 2, p. 196-210Article in journal (Refereed) Published
Abstract [en]

Most ecosystem functions and related services involve species interactions across trophic levels, for example, pollination and biological pest control. Despite this, our understanding of ecosystem function in multitrophic communities is poor, and research has been limited to either manipulation in small communities or statistical descriptions in larger ones. Recent advances in food web ecology may allow us to overcome the trade-off between mechanistic insight and ecological realism. Molecular tools now simplify the detection of feeding interactions, and trait-based approaches allow the application of dynamic food web models to real ecosystems. We performed the first test of an allometric food web model's ability to replicate temporally nonaggregated abundance data from the field and to provide mechanistic insight into the function of predation. We aimed to reproduce and explore the drivers of the population dynamics of the aphid herbivore Rhopalosiphum padi observed in ten Swedish barley fields. We used a dynamic food web model, taking observed interactions and abundances of predators and alternative prey as input data, allowing us to examine the role of predation in aphid population control. The inverse problem methods were used for simultaneous model fit optimization and model parameterization. The model captured >70% of the variation in aphid abundance in five of ten fields, supporting the model-embodied hypothesis that body size can be an important determinant of predation in the arthropod community. We further demonstrate how in-depth model analysis can disentangle the likely drivers of function, such as the community's abundance and trait composition. Analysing the variability in model performance revealed knowledge gaps, such as the source of episodic aphid mortality, and general method development needs that, if addressed, would further increase model success and enable stronger inference about ecosystem function. The results demonstrate that confronting dynamic food web models with abundance data from the field is a viable approach to evaluate ecological theory and to aid our understanding of function in real ecosystems. However, to realize the full potential of food web models, in ecosystem function research and beyond, trait-based parameterization must be refined and extended to include more traits than body size. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society

Keywords
agricultural pests, allometry, body mass, conservation biological control, herbivore suppression, multitrophic functioning, predator–prey interactions, species traits
National Category
Bioinformatics and Systems Biology
Research subject
Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-16247 (URN)10.1111/1365-2656.12892 (DOI)000458963200002 ()30079547 (PubMedID)2-s2.0-85052925738 (Scopus ID)
Available from: 2018-10-01 Created: 2018-10-01 Last updated: 2019-03-07Bibliographically approved
Roubinet, E., Jonsson, T., Malsher, G., Staudacher, K., Traugott, M., Ekbom, B. & Jonsson, M. (2018). High Redundancy as well as Complementary Prey Choice Characterize Generalist Predator Food Webs in Agroecosystems. Scientific Reports, 8, Article ID 8054.
Open this publication in new window or tab >>High Redundancy as well as Complementary Prey Choice Characterize Generalist Predator Food Webs in Agroecosystems
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 8054Article in journal (Refereed) Published
Abstract [en]

Food web structure influences ecosystem functioning and the strength and stability of associated ecosystem services. With their broad diet, generalist predators represent key nodes in the structure of many food webs and they contribute substantially to ecosystem services such as biological pest control. However, until recently it has been difficult to empirically assess food web structure with generalist predators. We utilized DNA-based molecular gut-content analyses to assess the prey use of a set of generalist invertebrate predator species common in temperate agricultural fields. We investigated the degree of specialization of predator-prey food webs at two key stages of the cropping season and analysed the link temperature of different trophic links, to identify non-random predation. We found a low level of specialization in our food webs, and identified warm and cool links which may result from active prey choice or avoidance. We also found a within-season variation in interaction strength between predators and aphid pests which differed among predator species. Our results show a high time-specific functional redundancy of the predator community, but also suggest temporally complementary prey choice due to within-season succession of some predator species.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Ecology
Research subject
Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-15588 (URN)10.1038/s41598-018-26191-0 (DOI)000432789300032 ()29795226 (PubMedID)2-s2.0-85047507398 (Scopus ID)
Available from: 2018-06-14 Created: 2018-06-14 Last updated: 2019-02-20Bibliographically approved
Jonsson, T., Kaartinen, R., Jonsson, M. & Bommarco, R. (2018). Predictive power of food web models based on body size decreases with trophic complexity. Ecology Letters, 21(5), 702-712
Open this publication in new window or tab >>Predictive power of food web models based on body size decreases with trophic complexity
2018 (English)In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 21, no 5, p. 702-712Article in journal (Refereed) Published
Abstract [en]

Food web models parameterised using body size show promise to predict trophic interaction strengths (IS) and abundance dynamics. However, this remains to be rigorously tested in food webs beyond simple trophic modules, where indirect and intraguild interactions could be important and driven by traits other than body size. We systematically varied predator body size, guild composition and richness in microcosm insect webs and compared experimental outcomes with predictions of IS from models with allometrically scaled parameters. Body size was a strong predictor of IS in simple modules (r(2)=0.92), but with increasing complexity the predictive power decreased, with model IS being consistently overestimated. We quantify the strength of observed trophic interaction modifications, partition this into density-mediated vs. behaviour-mediated indirect effects and show that model shortcomings in predicting IS is related to the size of behaviour-mediated effects. Our findings encourage development of dynamical food web models explicitly including and exploring indirect mechanisms.

Keywords
Allometric trophic network model, body size ratio, indirect effects, indirect interactions, interaction strength, non-consumptive effect, predator-prey interaction, species' traits, trophic interaction modification
National Category
Ecology
Research subject
Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-15171 (URN)10.1111/ele.12938 (DOI)000430120400011 ()29575347 (PubMedID)2-s2.0-85044379453 (Scopus ID)
Available from: 2018-05-25 Created: 2018-05-25 Last updated: 2019-02-20Bibliographically approved
Jonsson, T. (2017). Conditions for Eltonian Pyramids in Lotka-Volterra Food Chains. Scientific Reports, 7, Article ID 10912.
Open this publication in new window or tab >>Conditions for Eltonian Pyramids in Lotka-Volterra Food Chains
2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 10912Article in journal (Refereed) Published
Abstract [en]

In ecological communities consumers (excluding parasites and parasitoids) are in general larger and less numerous than their resource. This results in a well-known observation known as 'Eltonian pyramids' or the ` pyramid of numbers', and metabolic arguments suggest that this pattern is independent of the number of trophic levels in a system. At the same time, Lotka-Volterra (LV) consumer-resource models are a frequently used tool to study many questions in community ecology, but their capacity to produce Eltonian pyramids has not been formally analysed. Here, I address this knowledge gap by investigating if and when LV food chain models give rise to Eltonian pyramids. I show that Eltonian pyramids are difficult to reproduce without density-dependent mortality in the consumers, unless biologically plausible relationships between mortality rate and interaction strength are taken into account.

National Category
Ecology
Research subject
Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-14167 (URN)10.1038/s41598-017-11204-1 (DOI)000409562000059 ()28883486 (PubMedID)2-s2.0-85029052365 (Scopus ID)
Available from: 2017-09-27 Created: 2017-09-27 Last updated: 2019-02-20Bibliographically approved
Jonsson, T. (2017). Metabolic theory predicts animal self-thinning. Journal of Animal Ecology, 86(3), 645-653
Open this publication in new window or tab >>Metabolic theory predicts animal self-thinning
2017 (English)In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 86, no 3, p. 645-653Article in journal (Refereed) Published
Abstract [en]
  1. The metabolic theory of ecology (MTE) predicts observed patterns in ecology based on metabolic rates of individuals. The theory is influential but also criticized for a lack of firm empirical evidence confirming MTE's quantitative predictions of processes, e.g. outcome of competition, at population or community level.
  2. Self-thinning is a well-known population level phenomenon among plants, but a much less studied phenomenon in animal populations and no consensus exists on what a universal thinning slope for animal populations might be, or if it exists.
  3. The goal of this study was to use animal self-thinning as a tool to test population-level predictions from MTE, by analysing (i) if self-thinning can be induced in populations of house crickets (Acheta domesticus) and (ii) if the resulting thinning trajectories can be predicted from metabolic theory, using estimates of the species-specific metabolic rate of A. domesticus.
  4. I performed a laboratory study where the growth of A. domesticus was followed, from hatching until emergence as adults, in 71 cohorts of five different starting densities.
  5. Ninety-six per cent of all cohorts in the three highest starting densities showed evidence of self-thinning, with estimated thinning slopes in general being remarkably close to that expected under metabolic constraints: A cross-sectional analysis of all data showing evidence of self-thinning produced an ordinary least square (OLS) slope of −1·11, exactly that predicted from specific metabolic allometry of A. domesticus. This result is furthermore supported by longitudinal analyses, allowing for independent responses within cohorts, producing a mean OLS slope across cohorts of −1·13 and a fixed effect linear mixed effects models slope of −1·09. Sensitivity analysis showed that these results are robust to how the criterion for on-going self-thinning was defined. Finally, also as predicted by metabolic theory, temperature had a negative effect on the thinning intercept, producing an estimate of the activation energy identical to that suggested by MTE.
  6. This study demonstrates a direct link between the metabolic rate of individuals and a population-level ecological process and as such provides strong support for research that aims to integrate body mass, via its effect on metabolism, consumption and competition, into models of populations and communities.
Keywords
¾ scaling law, animal self-thinning, metabolic allometry, metabolic rate, metabolic scaling, metabolic theory of ecology
National Category
Ecology
Research subject
Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-13554 (URN)10.1111/1365-2656.12638 (DOI)000398826400023 ()28102900 (PubMedID)2-s2.0-85013678153 (Scopus ID)
Available from: 2017-05-11 Created: 2017-05-11 Last updated: 2019-02-20Bibliographically approved
Banks, H. T., Banks, J. E., Bommarco, R., Curtsdotter, A., Jonsson, T. & Laubmeier, A. N. (2017). Parameter estimation for an allometric food web model. International journal of pure and applied mathematics, 114(1), 143-160
Open this publication in new window or tab >>Parameter estimation for an allometric food web model
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2017 (English)In: International journal of pure and applied mathematics, ISSN 1311-8080, E-ISSN 1314-3395, Vol. 114, no 1, p. 143-160Article in journal (Refereed) Published
Abstract [en]

The application of mechanistic models to natural systems is of interest to ecological researchers. We use the mechanistic Allometric Trophic Network (ATN) model, whichis well-studied for controlled and theoretical systems, to describe the dynamics of the aphidRhopalosiphum padi in an agricultural field. We diagnose problems that arise in a first attemptat a least squares parameter estimation on this system, including formulation of the modelfor the inverse problem and information content present in the data. We seek to establishwhether the field data, as it is currently collected, can support parameter estimation for theATN model.

National Category
Ecology
Research subject
Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-14227 (URN)10.12732/ijpam.v114i1.12 (DOI)2-s2.0-85018945115 (Scopus ID)
Available from: 2017-10-13 Created: 2017-10-13 Last updated: 2019-02-20Bibliographically approved
Jonsson, A., Jonsson, T. & Toräng, P. (2017). Utvärdering av Hornborgasjöns restaurering: måluppfyllelse och effekter på biologisk mångfald med fokus på vegetation och fågelfauna.
Open this publication in new window or tab >>Utvärdering av Hornborgasjöns restaurering: måluppfyllelse och effekter på biologisk mångfald med fokus på vegetation och fågelfauna
2017 (Swedish)Report (Other academic)
Abstract [sv]

Hornborgasjön räknas idag som en av Sveriges rikaste fågelsjöar och är internationellt utpekad som en av Sveriges värdefullaste våtmarker. Sjön har stor betydelse som både rast- och häckplats för en mängd fågelarter. Området är också av stort intresse för friluftslivet och som ett levande kulturlandskap. Under de senaste 150 åren har Hornborgasjön genomgått stora förändringar. En serie av sjösänkningar under 1800 och 1900-talen ledde till kraftig igenväxning och följdes av ett storskaligt restaureringsprojekt i senare tid. Syftet med Hornborgasjöns restaurering var att säkerställa Hornborgasjöns framtid som fågelsjö. Restaureringen är ett av Sveriges största naturvårdsprojekt. I denna rapport har vi utvärderat hur Hornborgasjöns restaurering påverkat vegetation och fågelfauna. Syftet var att analysera om och till vilken grad de biologiska målen med restaureringen uppnåtts.För att utvärdera måluppfyllelsen har vi i första hand jämfört olika naturtypers utbredning mellan åren 1905 och 2010 samt förändringar i fågelfaunan under flera tidsperioder. Analyser av vegetationskartor visar att vass- och buskområden kraftigt reducerats och att en stor öppen vattenspegel och omgivande mader återskapats. Våtmarksfåglarnas numerär har generellt sett återhämtat sig från igenväxningsperioden och är för vissa arter till och med större än vid förra sekelskiftet. För vissa naturtyper och fågelarter, som till exempel vassområden och häckande vadare, är dagens situation dock inte i linje med målen. Det står ändå klart att det övergripande målet och många av de mer specifika delmålen har uppfyllts så att Hornborgasjön idag är en levande våtmark med stort antal häckande och rastande fågelarter.I analyser av fågeldata från senare tid finns indikationer på negativa trender som man behöver vara observant på för att för framtiden säkra en biologiskt rik Hornborgasjö. En utmaning för denna utvärdering har dock varit bristen på högkvalitativa och jämförbara data att basera analyserna på. Vi belyser därför vikten av att ha ett fungerande övervakningssystem som kontinuerligt följer upp statusen i ekosystemet.

Publisher
p. 54
National Category
Ecology
Research subject
Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-14228 (URN)
Available from: 2017-10-13 Created: 2017-10-13 Last updated: 2019-02-20Bibliographically approved
Jonsson, T. & Setzer, M. (2015). A freshwater predator hit twice by effects of warming across trophic levels. Nature Communications, 6, Article ID 5992.
Open this publication in new window or tab >>A freshwater predator hit twice by effects of warming across trophic levels
2015 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 6, article id 5992Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Nature Publishing Group, 2015
National Category
Ecology
Research subject
Natural sciences; Ecological Modelling Group
Identifiers
urn:nbn:se:his:diva-10628 (URN)10.1038/ncomms6992 (DOI)000348812100010 ()25586020 (PubMedID)2-s2.0-84923096522 (Scopus ID)
Available from: 2015-01-30 Created: 2015-01-30 Last updated: 2017-12-05Bibliographically approved
Roubinet, E., Straub, C., Jonsson, T., Staudacher, K., Traugott, M., Ekbom, B. & Jonsson, M. (2015). Additive effects of predator diversity on pest control caused by few interactions among predator species. Ecological Entomology, 40(4), 362-371
Open this publication in new window or tab >>Additive effects of predator diversity on pest control caused by few interactions among predator species
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2015 (English)In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 40, no 4, p. 362-371Article in journal (Refereed) Published
Place, publisher, year, edition, pages
John Wiley & Sons, 2015
National Category
Ecology
Research subject
Natural sciences
Identifiers
urn:nbn:se:his:diva-11993 (URN)10.1111/een.12188 (DOI)000357479700005 ()2-s2.0-84935757488 (Scopus ID)
Available from: 2016-02-29 Created: 2016-02-29 Last updated: 2017-11-30Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5234-9576

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