Lennart Persson

Lennart Persson
Umeå University | UMU · Department of Ecology and Environmental Science

PhD

About

207
Publications
22,714
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18,708
Citations
Citations since 2017
0 Research Items
4370 Citations
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
Additional affiliations
June 1982 - June 1988
Lund University
Position
  • Professor (Assistant)

Publications

Publications (207)
Article
Background In recent decades, many attempts have been made to restore eutrophic lakes through biomanipulation. Reducing the populations of planktivorous and benthivorous fish (either directly or through stocking of piscivorous fish) may induce ecosystem changes that increase water transparency and decrease the risk of algal blooms and fish kills, a...
Article
Full-text available
Patterns in biomass production are determined by resource input (productivity) and trophic transfer efficiency. At fixed resource input, variation in consumer biomass production has been related to food quality, metabolic type and diversity among species. In contrast, intraspecific variation in individual body size because of ontogenetic developmen...
Article
Many marine ecosystems have undergone 'regime shifts', i.e. abrupt reorganizations across trophic levels. Establishing whether these constitute shifts between alternative stable states is of key importance for the prospects of ecosystem recovery and for management. We show how mechanisms underlying alternative stable states caused by predator-prey...
Article
1.Coexistence of predators that share the same prey is common. This is still the case in size structured predator communities where predators consume prey species of different sizes (interspecific prey responses) or consume different size classes of the same species of prey (intraspecific prey responses).2.A mechanism has recently been proposed to...
Conference Paper
Background/Question/Methods Many animal species, in particular those that grow over substantial ranges of body size between birth and maturation, occupy different ecological niches in different stages of their life as during ontogeny they change, for example, their use of resources and/or habitats. Such ontogenetic niche shifts are especially imp...
Article
Humic lakes with a high external supply of DOC and low input of nutrients can often support a high biomass of metazoan zooplankton. In such lakes, autotrophic algae compete with bacteria for inorganic nutrients, but bacteria support mixotrophic growth. Consequently, planktonic communities are often dominated by mixotrophic flagellates, while obliga...
Article
Full-text available
Food-dependent growth and size-dependent interactions form cornerstones in the dynamics of fish populations. Using two freshwater examples, we illustrate the importance of considering both these cornerstones for understanding system dynamics. Moreover, a proper understanding of the dynamics requires mechanistic linkages between individual-, populat...
Article
Full-text available
Theoretical studies show that both cannibalism and intraspecific resource competition can have major effects on population dynamics. Cannibalistic intensity, offspring size, harvesting and refuge availability are important factors affecting the interplay between cannibalism and competition. We studied two populations of the common guppy (Poecilia r...
Conference Paper
Background/Question/Methods In size-structured populations theory predicts that population structure is determined by stage-specific resource use efficiencies. When adults are more efficient energetically the population is dominated by juveniles (maturation regulation), and when juveniles are more efficient energetically the population is dominate...
Conference Paper
Background/Question/Methods The potential occurrence of alternative stable states, ASS, (i.e. the presence of hysteresis) in marine food-webs is receiving increasing attention. If present, ASS have important consequences for how to manage exploitation of the oceans. For example, by preventing recovery of e.g. overexploited top piscivores followin...
Article
Full-text available
Occurrence of cannibalism and inferior competitive ability of predators compared to their prey have been suggested to promote coexistence in size-structured intraguild predation (IGP) systems. The intrinsic size-structure of fish provides the necessary prerequisites to test whether the above mechanisms are general features of species interactions i...
Article
Using a size-structured population model, life-history information and records of piscivores in systems without prey fish, we analysed the role of the timing of shifting from small-to-large invertebrate prey types in regulating piscivore performance, especially under conditions of low availability of prey fish. Large invertebrate prey are generally...
Article
Abstract Catastrophic collapses of top predators have revealed trophic cascades and community structuring by top-down control. When populations fail to recover after a collapse, this may indicate alternative stable states in the system. Overfishing has caused several of the most compelling cases of these dynamics, and in particular Atlantic cod sto...
Article
Ontogenetic development is a fundamental aspect of the life history of all organisms and has major effects on population and community dynamics. We postulate a general conceptual framework for understanding these effects and claim that two potential energetics bottlenecks at the level of the individual organism--the rate by which it develops and th...
Data
Full-text available
Background In lakes that have become eutrophic due to sewage discharges or nutrient runoff from land, problems such as algal blooms and oxygen deficiency often persist even when nutrient supplies have been reduced. One reason is that phosphorus stored in the sediments can exchange with the water. There are indications that the high abundance of phy...
Article
Full-text available
In the study of mechanisms structuring fish communities, mixed competition–predation interactions where large predators feed on prey fish versus those in which small predators compete with prey fish for a shared prey have been the focus of substantial research. We used a long-term data set from a system inhabited by brown trout (Salmo trutta) (pred...
Article
1. Size-dependent interactions and habitat complexity have been identified as important factors affecting the persistence of intraguild predation (IGP) systems. Habitat complexity has been suggested to promote intraguild (IG) prey and intraguild predator coexistence through weakening trophic interactions particularly the predation link. 2. Here, we...
Article
Most organisms show substantial changes in size or morphology after they become independent of their parents and have to find their own food. Furthermore, the rate at which these changes occur generally depends on the amount of food they ingest. In this book, André de Roos and Lennart Persson advance a synthetic and individual-based theory of the e...
Chapter
This chapter provides a summary of the topics covered by the present volume. The summary serves the purpose of clearly showing how different chapters fit together in a general framework with respect to model approaches as well as results obtained. Reading this summary chapter will show readers the different types of community modules that will be a...
Chapter
This chapter focuses on consumer-resource dynamics in systems where consumers of different sizes compete for a shared resource. It considers the implications of three important aspects of consumer life history: the explicit handling of a juvenile period leading to a delay between the time when an individual is born to when it starts to reproduce; t...
Chapter
This chapter discusses a variety of positive interactions between predators foraging on different stages of the same prey species, which all emerge owing to the biomass overcompensation that may occur in prey life history stages in response to increased mortality. These interactions include emergent facilitation of specialist predators by generalis...
Chapter
This chapter considers the consequences for community structure of ontogenetic diet shifts that involve the use of different resources in different life history stages, whereby these resources are in limited supply and are hence competed for by all individuals foraging on them. It explores the consequences of ontogenetic diet shifts using stage-str...
Chapter
This chapter first considers the question of how ecologists have conceptualized populations. In other words, how has their research looked at “group[s] of individuals of one species”? It reflects on the classical models that form the theoretical basis of population ecology: the Lotka–Volterra competition model, Lotka–Volterra predator–prey model, a...
Chapter
This chapter discusses the emergence of a positive feedback between the density of predators and the availability of its food, mediated through biomass overcompensation in the prey life history stage that it forages on. This positive feedback between predation, prey availability, and thus predator population growth rate manifests itself at the popu...
Chapter
The previous two chapters discussed how the size scaling of foraging and metabolic rates affected the dynamics of consumer-resource systems. Using different modeling approaches, it was shown that stage-dependent competitive ability was the main predictor of population dynamics; that is, it largely set the conditions for different types of cycles to...
Chapter
This chapter investigates the necessary conditions for the biomass in particular size ranges of a population to increase in response to an increase in mortality, and how the overcompensation comes about through a change in the population energetics. Ultimately, this overcompensation in stage-specific biomass solely results from the interplay betwee...
Chapter
This chapter considers how stage structure and ontogenetic niche shifts may affect the coexistence between two consumer species competing for two resources in the absence and presence of predators, and how ontogenetic niche shifts may give rise to alternative stable states. More specifically, the analysis will use techniques developed within the co...
Book
Most organisms show substantial changes in size or morphology after they become independent of their parents and have to find their own food. Furthermore, the rate at which these changes occur generally depends on the amount of food they ingest. This book advances a synthetic and individual-based theory of the effects of this plastic ontogenetic de...
Chapter
This chapter discusses mixed interactions from a different perspective, taking as its point of departure the models for a structured prey, structured predator community with exclusive resources for both prey and predator that were analyzed in Chapter 6. For both the stage-structured biomass model and the size-structured model based on Kooijman–Metz...
Chapter
This chapter considers models where processes like foraging, metabolism, and mortality are continuous, whereas reproduction is assumed to take place as a discrete event at the start of the growth season. The assumption of discrete reproduction is relevant for many organisms living in seasonal environments (winter/summer, dry/wet seasons). The use o...
Chapter
This chapter shows that overcompensation and cohort cycles are also found in demand-driven systems, and that shifts in overcompensation patterns and cycle types can, as for supply-driven systems, be related to whether development or reproduction is more limited and controls the population at equilibrium. Furthermore, it considers whether dynamical...
Article
The theory of cannibal dynamics predicts a link between population dynamics and individual life history. In particular, increased individual growth has, in both modeling and empirical studies, been shown to result from a destabilization of population dynamics. We used data from a long-term study of the dynamics of two leech (Erpobdella octoculata)...
Article
Body size (≡ biomass) is the dominant determinant of population dynamical processes such as giving birth or dying in almost all species, with often drastically different behaviour occurring in different parts of the growth trajectory, while the latter is largely determined by food availability at the different life stages. This leads to the questio...
Conference Paper
Background/Question/Methods: Ontogenetic development of individuals between their time of birth and maturation characterizes the life history of virtually all biological species and uniquely distinguishes the fundamental units of ecology from those in other fields of natural science. Yet, classic ecological theory about population and community dyn...
Conference Paper
Background/Question/Methods Catastrophic collapses of apex predators have revealed how their top-down control of prey structures marine ecosystems through trophic cascades. After collapsing many of these predator populations fail to recover. For Atlantic cod the lack of recovery is often claimed to result from competition for zooplankton between p...
Article
1. In many populations, sufficient size variation to allow for cannibalism may develop not only among age cohorts but also within them. Here, we used data on resource dynamics, consumer body size distribution and gape size limitation to unravel mechanisms promoting cannibalism within cohorts of young-of-the-year (YOY) perch (Perca fluviatilis). 2....
Article
Full-text available
Cross-ecosystem movements of material and energy are ubiquitous. Aquatic ecosystems typically receive material that also includes organic matter from the surrounding catchment. Terrestrial-derived (allochthonous) organic matter can enter aquatic ecosystems in dissolved or particulate form. Several studies have highlighted the importance of dissolve...
Article
In basic intraguild predation (IGP) systems, predators and prey also compete for a shared resource. Theory predicts that persistence of these systems is possible when intraguild prey is superior in competition and productivity is not too high. IGP often results from ontogenetic niche shifts, in which the diet of intraguild predators changes as a re...
Article
1. Life-history omnivory or size-induced mixed competition–predation systems have under many conditions theoretically been shown to be fragile, whereas at the same time existing empirical data suggest such systems to be common in nature. 2. In a whole lake experiment covering 17 years, we analysed the effects of the introduction of the intraguild p...
Conference Paper
Background/Question/Methods Intraguild predation (IGP) has been suggested to be common in nature although theory suggests that the room for coexistence of intraguild consumer and intraguild predator is limited. Size-dependent interactions and refuges have been identified as important factors affecting the community dynamics of IGP systems. In a r...
Conference Paper
Background/Question/Methods The majority of animal species on Earth have a complex life cycle, characterized by distinct shifts in ecological niche during ontogeny. These ontogenetic niche shifts involve changes in resource use, habitat as well as susceptibility to predators. Ontogenetic niche shifts are especially common among species that grow...
Conference Paper
Background/Question/Methods Life history omnivory or size-induced mixed competition/predation systems have theoretically been shown to be fragile at the same time as existing empirical data suggests such systems to be common in nature. In a whole lake experiment covering 17 years, we analyzed the effects of the introduction of the intraguild prey...
Article
Full-text available
There is considerable variation in cannibalism between different species and also between individuals of different species, although relatively little is known about what creates this variation. We investigated the degree of cannibalism in guppy (Poecilia reticulata) populations originating from high and low predation environments in Trinidad, and...
Article
A study by Sumari (O. Sumari. 1971. Ann. Zool. Fenn. 8: 406-421) of the fish communities in 32 Finnish lakes concluded that the main factors affecting perch (Perca fluviatilis) populations were biotic, of which the competitive interspecific effect of roach (Rutilus rutilus) was the main one analysed. A reanalysis of this data set suggests that abio...
Article
Planktivorous fish are known to affect the zooplankton community both in terms of species composition and species specific morphological traits. Remains of cladocerans are deposited as microfossils in lake sediments, and the microfossil assembly hence refl ects the historical impact of the planktivore community in the lake. The microfossils of clad...
Article
Full-text available
Food webs can respond in surprising and complex ways to temporary alterations in their species composition. When such a perturbation is reversed, food webs have been shown to either return to the pre-perturbation community state or remain in the food web configuration that established during the perturbation. Here we report findings from a replicated...
Article
Full-text available
Tilman’s theory predicts the outcome of competition between two consumers sharing two resources on the basis of the shape of zero net-growth isoclines (ZNGIs). In his theory, intraspecific differences in resource use are not accounted for. Here we extend this theory to include situations where organisms undergo ontogenetic diet shifts, as these cha...
Article
Cannibalistic interactions generally depend on the size relationship between cannibals and victims. In many populations, a large enough size variation to allow for cannibalism may not only develop among age-cohorts but also within cohorts. We studied the implications of variation in hatching period length and initial cohort size for the emergence o...
Article
The degree to which growth in early life stages of animals is regulated via density-dependent feedbacks through prey resources is much debated. Here we have studied the influence of size- and density-dependent mechanisms as well as size-selective predation pressure by cannibalistic perch Perca fluviatilis on growth patterns of young-of-the-year (YO...
Article
1. Recent theory suggests that compensation or even overcompensation in stage-specific biomass can arise in response to increased mortality. Which stage that will show compensation depends on whether maturation or reproduction is the more limiting process in the population. Size-structured theory also provides a strong link between the type of regu...
Article
Full-text available
We hypothesize that size at hatching strongly affects population dynamics of cannibalistic fish species and is a crucial determinant of how populations respond to selective removal of large individuals (harvesting). We use a mechanistic mathematical model to study the relation between hatching size and response to harvesting mortality, using Eurasi...
Article
Full-text available
We investigated productivity at the basal trophic level in 15 unproductive lakes in a gradient ranging from clear-water to brown-water (humic) lakes in northern Sweden. Primary production and bacterial production in benthic and pelagic habitats were measured to estimate the variation in energy mobilization from external energy sources (primary prod...
Article
Variation in growth rates among individuals leading to the formation of broad size distributions is commonly observed in animal cohorts. Here we use laboratory derived size–scaling relationships to identify mechanisms driving changes in size distribution patterns within cohorts during early ontogeny. We introduced young-of-the-year perch Perca fluv...
Conference Paper
Background/Question/Methods Terrestrial organic carbon has long been recognized a significant subsidy to aquatic ecosystems via an uptake of dissolved organic carbon by bacteria and subsequent consumption by organisms at higher trophic levels. However, the effect of organic carbon input from adjacent ecosystems on benthic food webs has not been ad...
Article
Full-text available
Productivity denotes the rate of biomass synthesis in ecosystems and is a fundamental characteristic that frames ecosystem function and management. Limitation of productivity by nutrient availability is an established paradigm for lake ecosystems. Here, we assess the relevance of this paradigm for a majority of the world's small, nutrient-poor lake...
Article
1. The size of an individual is an important determinant of its trophic position and the type of interactions it engages in with other heterospecific and conspecific individuals. Consequently an individual’s ecological role in a community changes with its body size over ontogeny, leading to that trophic interactions between individuals are a size-d...
Article
This study quantified new biomass production of algae and bacteria in both benthic and pelagic habitats of clear-water lakes to contrast how carbon from the atmosphere and terrestrial sources regulates whole-lake metabolism. We studied four small unproductive lakes in subarctic northern Sweden during one summer season. The production of new biomass...
Article
Full-text available
Size-selective mortality inevitably leads to a decrease in population density and exerts a direct negative effect on targeted size classes. But density and population size structure are also shaped by food-dependent processes, such as individual growth, maturation, and reproduction. Mortality relaxes competition and thereby alters the dynamic inter...
Article
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A high degree of trophic polymorphism has been associated with the absence of high variability in population density. An explanation for this pattern is that density fluctuations may influence selective regime forms in populations. Still, only few studies have investigated evolutionary dynamics in fluctuating populations. Here we report on a multiy...
Article
Full-text available
Cod stocks in the North West Atlantic and the Baltic Sea have shown similar dynamics in recent decades with a rapid decline in abundance and a lack of stock recovery following a period of large biomass. We explore whether the lack of recovery can be ascribed to an emergent Allee effect, which is a mechanism intrinsic to the community in contrast to...
Article
Full-text available
In seasonal environments, accumulated energy reserves are important to avoid starvation mortality during periods of low resource levels. Here we investigated patterns of energy accumulation and the importance of growth history for winter survival in young-of-the-year Eurasian perch (Perca fluviatilis). Under simulated winter conditions in aquaria,...
Article
Full-text available
Prey in natural communities are usually shared by many predator species. How predators coexist while competing for the same prey is one of the fundamental questions in ecology. Here, we show that competing predator species may not only coexist on a single prey but even help each other to persist if they specialize on different life history stages o...
Article
Full-text available
Most organisms exhibit a substantial size variation among individuals due to individual differences in experienced biotic and abiotic environmental conditions and because individuals undergo growth and development during most of their life time. One important issue in this context is how size variation within cohorts may develop over time. Here, we...
Article
Full-text available
Recent theory suggests that absolute population size may qualitatively influence the outcome of evolution under disruptive selection in asexual populations. Large populations are predicted to undergo rapid evolutionary branching; however, in small populations, the waiting time to branching increases steeply with decreasing abundance, and below a cr...
Article
Recreational angling opportunities in lakes are distributed across landscapes and attract anglers based on the combination of angling quality, travel distance, and availability of facilities. The relationship between angler density and fishing quality, as measured by catch rate, represents a numerical response that is analogous to a predator numeri...
Chapter
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Article
We formulate and analyze an archetypal consumer-resource model in terms of ordinary differential equations that consistently translates individual life history processes, in particular food-dependent growth in body size and stage-specific differences between juveniles and adults in resource use and mortality, to the population level. This stage-str...
Article
For most consumer species, winter represents a period of harsh food conditions in addition to the physiological strain that results from the low ambient temperatures. In size-structured populations, larger-bodied individuals do better during winter as they have larger energy reserves to buffer starvation periods. In contrast, smaller-bodied individ...
Article
Full-text available
We analyze a stage-structured biomass model for size-structured consumer-resource interactions. Maturation of juvenile consumers is modeled with a food-dependent function that consistently translates individual-level assumptions about growth in body size to the population level. Furthermore, the model accounts for stage-specific differences in reso...
Article
Full-text available
The majority of taxa grow significantly during life history, which often leads to individuals of the same species having different ecological roles, depending on their size or life stage. One aspect of life history that changes during ontogeny is mortality. When individual growth and development are resource dependent, changes in mortality can affe...
Article
Full-text available
Size variation among individuals born at the same time in a common environment (within cohorts) is a common phenomenon in natural populations. Still, the mechanisms behind the development of such variation and its consequences for population processes are far from clear. We experimentally investigated the development of early within-cohort size var...
Article
The majority of taxa grow significantly during life history, which often leads to individuals of the same species having different ecological roles, depending on their size or life stage. One aspect of life history that changes during ontogeny is mortality. When individual growth and development are resource dependent, changes in mortality can affe...
Article
Full-text available
Many top-predator fish stocks in both freshwater and marine systems have collapsed as a result of overharvesting. Consequently, some of these communities have shifted into seemingly irreversible new states. We showed, for predators feeding on prey that exhibit food-dependent growth, that culling of fish prey may promote predator recovery. We remove...
Article
Full-text available
There is extensive evidence that some species of ecological generalists, which use a wide diversity of resources, are in fact heterogeneous collections of relatively specialized individuals. This within-population variation, or “individual specialization,” is a key requirement for frequency-dependent interactions that may drive a variety of types o...
Article
Full-text available
Resource polymorphism is a well-known phenomenon in many taxa, assumed to be a consequence of strong competition for resources and to be facilitated by stable environments and the presence of several profitable resources on which to specialize. In fish, resource polymorphism, in the form of planktivore-benthivore pairs, is found in a number of spec...
Article
Conceptual models of lake ecosystem structure and function have generally assumed that energy in pelagic systems is derived from in situ photosynthesis and that its use by higher trophic levels depends on the average properties of individuals in consumer populations. These views are challenged by evidence that allochthonous subsidies of organic car...
Article
Full-text available
Resource polymorphism is a well‐known phenomenon in many taxa, assumed to be a consequence of strong competition for resources and to be facilitated by stable environments and the presence of several profitable resources on which to specialize. In fish, resource polymorphism, in the form of planktivore‐benthivore pairs, is found in a number of spec...
Article
Many animal species live in groups. Group living may increase exploitation competition within the group, and variation among groups in intra-group competition intensity could induce life-history variability among groups. Models of physiologically structured populations generally predict single generation cycles, driven by exploitation competition w...
Article
1. In size-structured communities where individuals grow in size over their life cycle, interactions between species will shift between competitive and predatory interactions depending on size relationships. The outcome of interactions will subsequently depend on the strength of competitive and predatory interactions, respectively. 2. In a whole la...
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Full-text available
Question: How is the process of evolutionary branching influenced by demographic stochasticity? Mathematical methods: Adaptive dynamics of (i) a simple consumer-resource model and (ii) an analogous but individual-based model with finite population size. Key assumptions: Consumers have access to two habitats with dynamic resources. The fraction of t...