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Journal Cover Theoretical Ecology
  [SJR: 1.255]   [H-I: 19]   [12 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1874-1746 - ISSN (Online) 1874-1738
   Published by Springer-Verlag Homepage  [2350 journals]
  • Models for alarm call behaviour
    • Authors: Luciana Mafalda Elias de Assis; Raul Abreu de Assis; Moiseis Cecconello; Ezio Venturino
      Pages: 1 - 18
      Abstract: The evolution of alarm call behaviour under individual selection is studied. Four mathematical models of increasing complexity are proposed and analysed. Theoretical conditions for the evolution of “selfish”, “mutualistic”, “altruistic” or “spiteful” alarm calls are established. The models indicate that the hypotheses of benefits of retaining group members or avoiding group detection are not sufficient to explain the evolution of alarm call behaviour, but serve as a complementary factor to facilitate its evolution in most cases. It is hypothesized that the evolution of alarm calls between non-kin should evolve probably when calls are mutualistic, mildly altruistic and there are beneficial group size effects against predation.
      PubDate: 2018-03-01
      DOI: 10.1007/s12080-017-0345-0
      Issue No: Vol. 11, No. 1 (2018)
  • Dynamics from a predator-prey-quarry-resource-scavenger model
    • Authors: Joanneke E. Jansen; Robert A. Van Gorder
      Pages: 19 - 38
      Abstract: Allochthonous resources can be found in many foodwebs and can influence both the structure and stability of an ecosystem. In order to better understand the role of how allochthonous resources are transferred as quarry from one predator-prey system to another, we propose a predator-prey-quarry-resource-scavenger (PPQRS) model, which is an extension of an existing model for quarry-resource-scavenger (a predator-prey-subsidy (PPS) model). Instead of taking the allochthonous resource input rate as a constant, as has been done in previous theoretical work, we explicitly incorporated the underlying predator-prey relation responsible for the input of quarry. The most profound differences between PPS and PPQRS system are found when the predator-prey system has limit cycles, resulting in a periodic rather than constant influx of quarry (the allochthonous resource) into the scavenger-resource interactions. This suggests that the way in which allochthonous resources are input into a predator-prey system can have a strong influence over the population dynamics. In order to understand the role of seasonality, we incorporated non-autonomous terms and showed that these terms can either stabilize or destabilize the dynamics, depending on the parameter regime. We also considered the influence of spatial motion (via diffusion) by constructing a continuum partial differential equation (PDE) model over space. We determine when such spatial dynamics essentially give the same information as the ordinary differential equation (ODE) system, versus other cases where there are strong spatial differences (such as spatial pattern formation) in the populations. In situations where increasing the carrying capacity in the ODE model drives the amplitude of the oscillations up, we found that a large carrying capacity in the PDE model results in a very small variation in average population size, showing that spatial diffusion is stabilizing for the PPQRS model.
      PubDate: 2018-03-01
      DOI: 10.1007/s12080-017-0346-z
      Issue No: Vol. 11, No. 1 (2018)
  • Do yearly temperature cycles reduce species richness' Insights from
           calanoid copepods
    • Authors: Harshana Rajakaruna; Mark Lewis
      Pages: 39 - 53
      Abstract: The metabolic theory of ecology (MTE) has explained the taxonomic richness of ectothermic species as an inverse function of habitat mean temperature. Extending this theory, we show that yearly temperature cycles reduce metabolic rates of taxa having short generation times. This reduction is due to Jensen’s inequality, which results from a nonlinear dependency of metabolic rate of organisms on temperature. It leads to a prediction that relatively lower species richness is found in habitats with larger amplitudes of yearly temperature cycles where mean temperatures and other conditions are similar. We show that metabolically driven generation time of a taxon also relates functionally to species richness, and similarly, its yearly cycles reduce richness. We test these hypotheses on marine calanoid copepods with 46,377 records of data collected by scientific cruise surveys in Mediterranean regions, across which the temperature amplitudes vary dramatically. We test both bio-energetic and phenomenological effects of temperature cycles on richness in 86 1° × 1° latitudinal and longitudinal spatial units. The models incorporated the effect of both periodic fluctuations and mean temperature explained 21.6% more variation in the data, with lower AIC, compared to models incorporated only the mean temperature. The study also gives insight into the basis of energetic-equivalence rule in MTE determining richness, which can be governed by generation time of taxon. The results of this study lead to the proposition that amplitude of yearly temperature cycles may contribute to both the longitudinal and the latitudinal differences in species richness and show how the metabolic theory can explain macro-ecological patterns arising from yearly temperature cycles.
      PubDate: 2018-03-01
      DOI: 10.1007/s12080-017-0347-y
      Issue No: Vol. 11, No. 1 (2018)
  • The dispersal success and persistence of populations with asymmetric
    • Authors: D. Scott Rinnan
      Pages: 55 - 69
      Abstract: Asymmetric dispersal is a common trait among populations, often attributed to heterogeneity and stochasticity in both environment and demography. The cumulative effects of population dispersal in space and time have been described with some success by Van Kirk and Lewis’s average dispersal success approximation (Bull Math Biol 59(1): 107–137 1997), but this approximation has been demonstrated to perform poorly when applied to asymmetric dispersal. Here we provide a comparison of different characterizations of dispersal success and demonstrate how to capture the effects of asymmetric dispersal. We apply these different methods to a variety of integrodifference equation population models with asymmetric dispersal, and examine the methods’ effectiveness in approximating key ecological traits of the models, such as the critical patch size and the critical speed of climate change for population persistence.
      PubDate: 2018-03-01
      DOI: 10.1007/s12080-017-0348-x
      Issue No: Vol. 11, No. 1 (2018)
  • Dynamic choices are most accurate in small groups
    • Authors: Julián Vicente-Page; Alfonso Pérez-Escudero; Gonzalo G. de Polavieja
      Pages: 71 - 81
      Abstract: According to the classic results of Galton and Condorcet, as well as in modern decision-making models, accuracy in groups increases with group size. However, these studies do not consider the naturally occurring situation in which individuals dynamically re-evaluate their decision with a possible change of opinion. The dynamics of re-evaluation in groups are very different to individual re-evaluation because individuals influence the group and the group influences the individual. We find that individual accuracy in a group is higher when individuals re-evaluate because all members have more access to social information, while in single decisions, those deciding first have less. This improvement is smaller in large groups as in this case errors can cascade across the members of the group before re-evaluation can correct them. The net result is a maximal accuracy at a small group size. We also analyzed the case in which individuals are influenced only by a small number of the other individuals. In this case, cascading errors affect the interacting subgroups but are very unlikely to reach the whole group. This results in a local optimum at a small group size but also an optimum at a very large size. We thus suggest that re-evaluation dynamics can make small and very large groups optimal. Also, features that may be seen as limitations, like an influence from only a small number of individuals, may turn to be beneficial when considering local animal interactions, here filtering out cascading of errors in the group when reconsideration dynamics takes place.
      PubDate: 2018-03-01
      DOI: 10.1007/s12080-017-0349-9
      Issue No: Vol. 11, No. 1 (2018)
  • Coexistence and displacement in consumer-resource systems with local and
           shared resources
    • Authors: Victoria M. Hunt; Joel S. Brown
      Pages: 83 - 93
      Abstract: Competition for local and shared resources is widespread. For example, colonial waterbirds consume local prey in the immediate vicinity of their colony, as well as shared prey across multiple colonies. However, there is little understanding of conditions facilitating coexistence vs. displacement in such systems. Extending traditional models based on type I and type II functional responses, we simulate consumer-resource systems in which resources are “substitutable,” “essential,” or “complementary.” It is shown that when resources are complementary or essential, a small increase in carrying capacity or decrease in handling time of a local resource may displace a spatially separate consumer species, even when the effect on shared resources is small. This work underscores the importance of determining both the nature of resource competition (substitutable, essential, or complementary) and appropriate scale-dependencies when studying metacommunities. We discuss model applicability to complex systems, e.g., urban wildlife that consume natural and anthropogenic resources which may displace rural competitors by depleting shared prey.
      PubDate: 2018-03-01
      DOI: 10.1007/s12080-017-0350-3
      Issue No: Vol. 11, No. 1 (2018)
  • Generalizing matrix structure affects the identification of least-cost
           paths and patch connectivity
    • Authors: Shantel J. Koenig; Darren J. Bender
      Pages: 95 - 109
      Abstract: Understanding and assessing landscape connectivity is often a primary goal when studying patchy or spatially structured populations. It is commonly accepted that the matrix plays a role in determining connectivity; however, it is not clear how the process of assessing connectivity is impacted by different ways in which the matrix may be represented, particularly if matrix structure is generalized to expedite analysis. We conducted a controlled experiment using computer simulations to evaluate the impact of increasing levels of matrix generalization on connectivity assessment using a constant arrangement of habitat patches. We varied matrix generalization for six simulated landscape patterns by adjusting the number of classes and level of pattern grain in 16 ways to yield sets of landscapes for which the matrix ranged from not generalized (i.e., heterogeneous) to completely generalized (i.e., homogeneous) while habitat placement was held constant. Least-cost paths were calculated for each landscape, and a spatial interaction model (SIM) was implemented to model the counts of patch inflows (immigration) and pairwise exchange. Applying a SIM allowed us to generate absolute outputs and explicitly compare the effect of changes to matrix generalization on connectivity. We found that both assessment of connections (i.e., measured distance and spatial delineation of least-cost paths) and patch inflows/pairwise exchange were highly sensitive to matrix generalization and that effects were inconsistent and unpredictable across the range of matrix representations, especially when estimating connectivity for individual patches. We conclude that matrix pattern may have an underappreciated effect on connectivity and that least-cost path delineation and connectivity assessment may be very sensitive to generalizations of the matrix. We suggest that sensitivity analysis of the matrix representation should be performed when conducting connectivity analyses.
      PubDate: 2018-03-01
      DOI: 10.1007/s12080-017-0351-2
      Issue No: Vol. 11, No. 1 (2018)
  • Landscape configuration drives persistent spatial patterns of occupant
    • Authors: Elizabeth A. Hamman; Scott A. McKinley; Adrian C. Stier; Craig W. Osenberg
      Pages: 111 - 127
      Abstract: Variation in the density of organisms among habitat patches is often attributed to variation in inherent patch properties. For example, higher quality patches might have higher densities because they attract more colonists or confer better post-colonization survival. However, variation in occupant density can also be driven by landscape configuration if neighboring patches draw potential colonists away from the focal habitat (a phenomenon we call propagule redirection). Here, we develop and analyze a stochastic model to quantify the role of landscape configuration and propagule redirection on occupant density patterns. We model a system with a dispersive larval stage and a sedentary adult stage. The model includes sensing and decision-making in the colonization stage and density-dependent mortality (a proxy for patch quality) in the post-colonization stage. We demonstrate that spatial variation in colonization is retained when the supply of colonists is not too high, post-colonization density-dependent survival is not too strong, and colonization events are not too frequent. Using a reef fish system, we show that the spatial variation produced by propagule redirection is comparable to spatial variation expected when patch quality varies. Thus, variation in density arising from the spatial patterning of otherwise identical habitat can play an important role in shaping long-term spatial patterns of organisms occupying patchy habitats. Propagule redirection is a potentially powerful mechanism by which landscape configuration can drive variation in occupant densities, and may therefore offer new insights into how populations may shift as landscapes change in response to natural and anthropogenic forces.
      PubDate: 2018-03-01
      DOI: 10.1007/s12080-017-0352-1
      Issue No: Vol. 11, No. 1 (2018)
  • Whence Lotka-Volterra'
    • Authors: James P. O’Dwyer
      Abstract: Competition in ecology is often modeled in terms of direct, negative effects of one individual on another. An example is logistic growth, modeling the effects of intraspecific competition, while the Lotka-Volterra equations for competition extend this to systems of multiple species, with varying strengths of intra- and interspecific competition. These equations are a classic and well-used staple of quantitative ecology, providing a framework to understand species interactions, species coexistence, and community assembly. They can be derived from an assumption of random mixing of organisms, and an outcome of each interaction that removes one or more individuals. However, this framing is somewhat unsatisfactory, and ecologists may prefer to think of phenomenological equations for competition as deriving from competition for a set of resources required for growth, which in turn may undergo their own complex dynamics. While it is intuitive that these frameworks are connected, and the connection is well-understood near to equilibria, here, we ask the question: when can consumer dynamics alone become an exact description of a full system of consumers and resources' We identify that consumer-resource systems with this property must have some kind of redundancy in the original description, or equivalently there is one or more conservation laws for quantities that do not change with time. Such systems are known in mathematics as integrable systems. We suggest that integrability in consumer-resource dynamics can only arise in cases where each species in an assemblage requires a distinct and unique combination of resources, and even in these cases, it is not clear that the resulting dynamics will lead to Lotka-Volterra competition.
      PubDate: 2018-04-24
      DOI: 10.1007/s12080-018-0377-0
  • Multiple hysteretic patterns from elementary population models
    • Authors: Theresa Wei Ying Ong; John Vandermeer
      Abstract: Critical transitions whereby small changes in conditions can cause large and irreversible changes in ecosystem states are a cause of increasing concern in ecology. Here, we focus on the irreversibility of these transitions, formally known as hysteresis. We explore how simple correlations between parameters in Lotka-Volterra predator-prey equations result in a variety of complicated hysteretic patterns. These patterns include “unattainable” stable states that once lost may never be recovered. We suspect these patterns to be common in natural systems, where interactions between diverse assemblages are unavoidable. Thus, understanding underlying hysteretic structures may be necessary for rescuing lost ecosystem states and avoiding future losses.
      PubDate: 2018-04-21
      DOI: 10.1007/s12080-018-0376-1
  • Correction to: Ocean zoning within a sparing versus sharing framework
    • Authors: Jennifer McGowan; Michael Bode; Matthew H. Holden; Katrina Davis; Nils C. Krueck; Maria Beger; Katherine L. Yates; Hugh P. Possingham
      Abstract: The article “Ocean zoning within a sparing versus sharing framework,” written by Jennifer McGowan, Michael Bode, Matthew H. Holden, Katrina Davis, Nils C. Krueck, Maria Beger, Katherine L. Yates, and Hugh P. Possingham, was originally published electronically on the publisher’s internet portal.
      PubDate: 2018-04-16
      DOI: 10.1007/s12080-018-0368-1
  • A flow network model for animal movement on a landscape with application
           to invasion
    • Authors: Rosalyn Rael; Caz Taylor
      Abstract: Animal movement, whether for foraging, mate-seeking, predator avoidance, dispersal, or migration, is a fundamental aspect of ecology that shapes spatial abundance distributions, genetic compositions, and dynamics of populations. A variety of movement models have been used for predicting the effects of natural or human-caused landscape changes, invading species, or other disturbances on local ecology. Here we introduce the flow network—a general modeling framework for population dynamics and movement in a metapopulation representing a network of habitat sites (nodes). Based on the principles of physical transport phenomena such as fluid flow through pipes (Pouiselle’s Law) and analogously, the flow of electric current across a circuit (Ohm’s Law), the flow network provides a novel way of modeling movement, where flow rates are functions of relative node pressures and the resistance to movement between them. Flow networks offer the flexibility of incorporating abiotic and biotic conditions that affect either pressures, resistance, or both. To illustrate an application of the flow network, we present a theoretical invasion scenario. We consider the effects of spatial structure on the speed of invasion by varying the spatial regularity of node arrangement. In the context of invasion, we model management actions targeting nodes or edges, and consider the effects on speed of invasion, node occupation, and total abundance. The flow network approach offers the flexibility to incorporate spatial heterogeneity in both rates of flow and site pressures and offers an intuitive approach to connecting population dynamics and landscape features to model movement.
      PubDate: 2018-04-04
      DOI: 10.1007/s12080-018-0373-4
  • Movement behaviour determines competitive outcome and spread rates in
           strongly heterogeneous landscapes
    • Authors: Gabriel Andreguetto Maciel; Frithjof Lutscher
      Abstract: Classical models for biological invasions were single-species models in homogeneous landscapes, but most invasions happen in the presence of interacting species and in heterogeneous environments. The combination of spatial variation and species interaction could alter the spreading process significantly. For example, the ‘environmental heterogeneity hypothesis of invasions’ posits that heterogeneity offers more opportunities for invaders and reduces the negative impact on native species. Environmental heterogeneity offers an obvious coexistence mechanism on the regional scale if two or more competing species have different spatial niches, i.e. if the local competitive advantage changes in space. We consider a more subtle mechanism of space use through individual movement behaviour when the local competitive advantage remains with the same species. Specifically, we model the densities of two species, diffusing and competing in an infinite landscape consisting of two types of patches. We include individual behaviour in terms of movement rate and patch preference. We consider the scenario that one of the species is the stronger local competitor in both patch types. We then uncover a number of mechanisms—based solely on movement behaviour—through which these two species can coexist regionally, how the inferior competitor can replace the superior competitor globally, or how a bistable situation can arise between the two. We calculate mutual invasion conditions as well as mutual spatial spread rates, and we show that spread rates may depend on movement parameters in unexpected ways.
      PubDate: 2018-03-10
      DOI: 10.1007/s12080-018-0371-6
  • Changing environmental spectra influence age-structured populations:
           increasing ENSO frequency could diminish variance and extinction risk in
           long-lived seabirds
    • Authors: Annie E. Schmidt; Louis W. Botsford; D. Patrick Kilduff; Russell W. Bradley; Jaime Jahncke; John M. Eadie
      Abstract: As global climate changes, there is increasing need to understand how changes in the frequencies of environmental variability affect populations. Age-structured populations have recently been shown to filter specific frequencies of environmental variability, favoring generational frequencies, and very low frequencies, a phenomenon known as cohort resonance. However, there has been little exploration of how changes in the spectra of environmental signals will affect the stability and persistence of age-structured populations. To examine this issue, we analyzed a likely example to show how changes in the frequency of an influential climate phenomenon, the El Niño-Southern Oscillation (ENSO), could affect a marine bird population. We used a density-dependent, age-structured population model to calculate the transfer function (i.e., the frequency-dependent sensitivity) of Brandt’s cormorant (Phalacrocorax penicillatus), a representative marine bird species known to be influenced by ENSO. We then assessed how the population would be affected by ENSO forcing that was doubled and halved in frequency. The transfer function indicated this population is most sensitive to variance at low frequencies, but does not exhibit the sensitivity to generational frequencies (cohort resonance) observed in shorter-lived species. Doubling the frequency of ENSO unexpectedly resulted in higher mean adult population abundance, lower variance, and lower probability of extinction, compared to forcing with the historical or reduced ENSO frequency. Our results illustrate how long-lived species with environmentally driven variability in recruitment, including many species of marine birds and fish, may respond in counterintuitive ways to anticipated changes in environmental variability.
      PubDate: 2018-03-06
      DOI: 10.1007/s12080-018-0372-5
  • Remembering the good and the bad: memory-based mediation of the
           food–safety trade-off in dynamic landscapes
    • Authors: Chloe Bracis; Eliezer Gurarie; Jeffery D. Rutter; R. Andrew Goodwin
      Abstract: Predator–prey interactions are central to fitness as animals simultaneously avoid death and consume resources to ensure growth and reproduction. Along with direct effects, predators can also exert strong non-consumptive effects. For example, prey shift habitat use in the presence of predators, a potentially learned behavior. The impact of cognition on movement and predator interactions is largely unexplored despite evidence of learned responses to predation threat. We explore how learning and spatial memory influence predator–prey dynamics by introducing predators into a memory-driven movement modeling framework. To model various aspects of risk, we vary predator behavior: their persistence and spatial correlation with the prey’s resources. Memory outperforms simpler movement processes most in patchy environments with more predictable predators that are more easily avoided once learned. In these cases, memory aids foragers in managing the food–safety trade-off. For example, particular parameterizations of the predation memory reduce encounters while maintaining consumption. We found that non-consumptive effects are highest in landscapes of concentrated, patchy resources. These effects are intensified when predators are highly correlated with the forager’s resources. Smooth landscapes provide more opportunities for foragers to simultaneously consume resources and avoid predators. Predators are able to effectively guard all resources in very patchy landscapes. These non-consumptive effects are also seen with the shift away from the best quality habitat compared to foraging in a predator-free environment.
      PubDate: 2018-02-19
      DOI: 10.1007/s12080-018-0367-2
  • Production of nitrate spikes in a model of ammonium biodegradation
    • Authors: I. R. Moyles; A. C. Fowler
      Abstract: Nitrification at the site of a contaminant ammonium plume from a former coal carbonisation plant can be modelled with three competing bacterial populations of Nitrosomonas, Nitrobacter, and Brocadia anammoxidans. Oscillations of chemical species at the site can be explained by a reduced model of ammonium competition between Nitrosomonas and B. anammoxidans which effectively acts as an activator-inhibitor system. Stable oscillations occur in conditions of low nutrient (ammonium) supply and this causes a spatial travelling wave in a borehole profile when diffusion is introduced.
      PubDate: 2018-02-17
      DOI: 10.1007/s12080-018-0370-7
  • Aggregating fields of annual crops to form larger-scale monocultures can
           suppress dispersal-limited herbivores
    • Authors: Collin B. Edwards; Jay A. Rosenheim; Moran Segoli
      Abstract: An important part of landscape ecology is determining how the arrangement (aggregation or fragmentation) of patches in space influences the population dynamics of foraging organisms. One hypothesis in agricultural ecology is that fine-grain spatial heterogeneity in cropping (many small agricultural fields) should provide better pest control than coarse-grain heterogeneity (few large agricultural fields); this hypothesis has been proposed as an explanation for the increased pest abundance associated with agricultural intensification. However, empirical studies have found mixed support for this hypothesis, and some, surprisingly, demonstrate a strong decrease in pest abundance with increased crop aggregation. We developed a spatially explicit simulation model of pest movement across an agricultural landscape to uncover basic processes that could reduce pest abundance in landscapes with fewer, larger fields. This model focuses on herbivore movement and does not include predation effects or other biological interactions. We found that field aggregation in the model led to severely reduced pest densities and further discovered that this relationship was due to an increased distance between fields and a decreased “target area” in more aggregated landscapes. The features that create a negative relationship between aggregation and pest densities rely on crop rotation and limited dispersal capabilities of the pests. These findings help to explain seemingly counter-intuitive empirical studies and provide an expectation for when field aggregation may reduce pest populations in agro-ecosystems.
      PubDate: 2018-02-16
      DOI: 10.1007/s12080-018-0369-0
  • The role of succession in the evolution of flammability
    • Authors: Isaac Kazuo Uyehara; Stephen W. Pacala
      Abstract: Fire-prone ecosystems contain plants that are both fire-adapted and flammable. It has been hypothesized that these plants were under selection to become more flammable, but it is unclear whether this could be adaptive for an individual plant. We propose arrested succession as a robust mechanism that supports the evolution of flammability in surface fire ecosystems without the need to invoke group selection or additional fitness benefits. We used the natural history of lodgepole pine (Pinus ponderosa) forests, longleaf pine (Pinus palustris) forests, and tall grass prairies to create a general mathematical model of surface fire ecosystems and solved for the evolutionarily stable strategy (ESS) level of flammability. In our model, fires always kill understory plants and only sometimes kill overstory plants. Thus, more flammable plants suffer increased mortality due to fires, but also more frequently arrest succession by clearing their understory of late successional competitors. Increased flammability was selected for when the probability of an overstory plant dying from an individual fire was below a maximum threshold and the rate of succession relative to fires was above a minimum threshold. Future studies can test our model predictions and help resolve whether or not plants have been selected to be more flammable.
      PubDate: 2018-02-03
      DOI: 10.1007/s12080-018-0366-3
  • Social transmission of migratory knowledge: quantifying the risk of losing
           migratory behavior
    • Authors: Andrew Foss-Grant; Sharon Bewick; William F. Fagan
      Abstract: When migration is a learned behavior, small populations have a significant problem of maintaining migratory knowledge across generations. These populations risk losing migratory behavior entirely, which may exacerbate existing stressors on population size. Here we investigated the success of various behavioral, demographic, and social factors towards maintaining migration within small populations. Using a discrete-time probabilistic model to simulate repeated migrations, we found that migratory group size plays an important role in maintaining migratory knowledge within the population. Rare, large groups allow for migratory knowledge to be spread to many individuals at once. When a population learns migration information incrementally, the presence of individuals that can learn quickly, therefore transitioning rapidly into leaders, has a profound impact on migrational persistence. Furthermore, small populations are better able to maintain migratory behavior when groups rely on informed leaders as compared to using collective group knowledge, even when that collective knowledge is heavily weighted towards knowledgeable individuals. Finally, we found that both species with short lifespans and species that migrate with fixed group compositions are at especially high risk of losing their migration behavior at small population sizes.
      PubDate: 2018-02-03
      DOI: 10.1007/s12080-017-0362-z
  • Resilience in a two-population system: interactions between Allee effects
           and connectivity
    • Authors: Carter L. Johnson; Alan Hastings
      Abstract: Resilience in ecosystems and resistance to regime shifts has been a major focus in ecological research. How migration and general network dynamics affect the resilience of populations or induce regime shift cascades is a particularly challenging open question in theoretical ecology. We focus on regime shifts in populations with variable-strength Allee effects to demonstrate the effect of migration on resilience in two-population systems with critical transitions. The result is a mathematical model that justifies the assumption that resilience can be averaged across connected populations and suggests several management strategies to either avoid or induce regime shift cascades.
      PubDate: 2018-01-29
      DOI: 10.1007/s12080-018-0365-4
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