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Abstract: Recent years have seen increasing demand for wider application of strategic environmental assessment (SEA), especially SEA of major policies, as a powerful instrument to safeguard the environment during the rapid industrialization and urbanization in China. Debates on SEA are concentrated on its feasibility and effective implementation in practice. This study applies Emergy analysis within the framework of social–economic–natural complex eco-system theory to overcome the limitations of methods used for assessing regional sustainability so far. This established model is tested in the case of Chinese paper industry to assess the sustainability of 5 policy scenarios. The results show that Emergy-based Indices (EbI) are more effective to measure the sustainability of industry complex ecosystem, thus EbI approach is very useful in SEAs on policy scenarios of a given complex ecosystem. [Copyright &y& Elsevier]

• Spatial patterns of a single species are studied in patchy environment. • The system contains three patches with different networks of corridors. • We find that the network with fully connected corridors is not optimal. • The construction of corridor has a risk of species extinction. Many authors have reported the risk of habitat fragmentation and the importance of connecting corridors between subpopulations (patches). However, we report that the connection of corridors may be harmful to species conservation. The paper deals with the birth and death processes of a single species living in a network composed of three patches. The disturbance due to a changing environment is assumed to affect only one patch. Two types of metapopulation models are applied. One is the lattice simulation model where we set a lattice as a patch. The other is based on metapopulation theory, which utilizes reaction-migration equations. The lattice simulation reveals that the connecting corridor between patches may be disadvantageous; the complete graph or a network with fully connected corridors is found not to be optimal for species conservation. Similar results are indicated by the application of metapopulation theory. We discuss the relationship between the risk of corridor construction and the effect of the hub patch. [ABSTRACT FROM AUTHOR]

• Estimating the geographical distribution of species has long been done in Ecology. • Appropriately measuring and showing uncertainty in the models is crucial. • In this paper we provide a method to map uncertainty using cartograms under a Bayesian framework. Predicting the geographical distribution of a species is a central topic in ecology, conservation and management of natural resources especially for invasive organisms. Invasive species can modify the structure and function of invaded ecosystems, altering their biodiversity, and causing significant economic losses locally and globally. Therefore, measuring and visualizing the uncertainty inherent in species' potential distributions is fundamental for effective biodiversity monitoring and planning conservation interventions. This paper discusses a new Bayesian approach to mapping this uncertainty using cartograms, previously published knowledge, and presence/absence data. [ABSTRACT FROM AUTHOR]

Highlights • The mining area and the surrounding land cover changes on the southern slope of Qilian Mountains in the northeast of Qinghai Tibet Plateau. • Estimating the surrounding ecosystem services variation and loss due to the spatial adjacency effect of the mining areas. • Trade-off analysis between mining benefits and loss of ecosystem service values in fragile Qinghai-Tibet Plateau. Abstract Surface mining can destroy the ecosystems and result in the loss of the service values of the surrounding ecosystems through direct occupation and indirect impact on the neighboring ecosystems. In the Qinghai-Tibet Plateau (QTP), where the ecological system is fragile and sensitive, the mining development has led to a series of ecological and environmental issues and social controversies and aroused much attention in the recent years. This paper selected six typical open-pit coal mines in the Southern Slope of Qilian Mountain (SSQM) in the northern QTP to monitor the changes of mining extent and the surrounding land cover from 1975 to 2016 and estimate the surrounding ecosystem service value (ESV) changes by considering spatial adjacency effects. A trade-off analysis is finally employed to compare the mining benefit and ESV loss associated with the development of mining areas. Results showed that the mining areas increased in six regions, especially after year 2000, which resulted in the decline of wetland, meadow and grassland areas. The regional ecosystem service values decreased with the expansion of mining areas, and the spatial adjacency effect has accelerated with the loss of ecosystem service value, especially the service value of wetlands and hydrological regulation function. The larger the mining extent and unit area value of the surrounding ecosystem services, the greater the ESV loss due to mining activities, and the dispersive and disorderly exploitation of mining areas will also result in a rapid increase in ESV loss, while mining development in areas with lower ESV is more beneficial. The results of this paper are instructive to the development and planning of mineral resources in Qinghai-Tibet Plateau and other ecologically fragile areas. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Highlights • The paper gives a survey to adaptive dynamics and reviews several eco-evolutionary models of prey–predator interactions. • General case of a prey–predator system that include an adaptive trait of the prey against predator activity is taken together with overview of typical specific examples of predator–prey models with Holling's type functional responses. • The study confirms that predator functional response affected by prey trait adaptation causes reversible and irreversible regime shifts and we distinguish typical cases. • It is proved that specialized adaptive trait changes induce stability or irreversible regime shift, whereas intraspecific competition asymmetry is necessary for reversible regime shifts, hysteresis or more complex dynamics. Abstract The paper concerns with regime shifts between multiple attractors in ecological predator–prey models and hysteresis phenomena caused by evolution. We present a survey of eco-evolutionary models with an adaptive trait affecting the prey defence or activity that influence predator functional response and give overview of typical consequences of the trait evolution to the predator–prey dynamics together with important references to related adaptive dynamics research. The selection and mutation process is modelled by a resident-mutant model (possible mutant invasion into a monomorphic resident population). Model derivations are given in detail for all of the common functional responses (Holling's type I, II, III and generalized). Different types of adaptive trait value dependences with respect to transient dynamics are distinguished according to the effect to the eco-system: we prove that if the prey adaptive trait evolution influence only the functional response of the predator, stable dynamics and irreversible abrupt regime changes are typical, whereas reversible regime shifts or more complex dynamics caused by adaptivity of the prey trait occur for trait adaptations that bring an advantage against predator together with intraspecific competition asymmetry. We confirm possibility of hysteresis eco-evolutionary cycle, persistent oscillations between different attractors of the ecological subsystem driven by adaptive trait dynamics. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • We develop a Tree-Grass spatiotemporal model (pulse fires) using PDEs and diffusion. • Existence of bi-stable (e.g. forest vs. grassland) traveling wave solutions. • Fire frequency influences the sign of traveling-wave speed (forest progress or not). Abstract Long term tree–grass dynamics is an important issue in many places around the world. Especially, if we intend to take into account environmental and human perturbations, like fire events, herbivory, etc. In this paper, we complete and extend temporal models developed in recent papers by Yatat et al. (2014, 2017) and Tchuinte Tamen et al. (2014) , using diffusion operators, into spatio-temporal models, in order to study the long term dynamics of a mosaic of forest and grassland in a humid context of Central Africa. We take into account local biomass diffusion, as well as local tree–grass competition for nutrients and light. For this model, we carry out a qualitative analysis that highlights some ecological thresholds shaping the dynamics of the system. In addition, we show that monostable and bistable travelling wave solutions may exist. We illustrate some of our theoretical results with numerical simulations, and, also explore the use of impulsive fires on the dynamics of a mosaic of forest and grassland in a humid savanna. We found that depending on fire-return time as well as difference in diffusion potential of woody and herbaceous vegetation, fire events are able to greatly slow down or even stop the progression of forest in humid regions. [ABSTRACT FROM AUTHOR]

This paper further develops a new way of modelling evolutionary game models with an emphasis on ecological realism, concerned with how ecological factors determine payoffs in evolutionary games. Our paper is focused on the impact of strategically neutral growth limiting factors and background fitness components on game dynamics and the form of the stability conditions for the rest points constituted by the intersections of the frequency and density nullclines. It is shown that for the density dependent case, that at the stationary state, the turnover coefficients (numbers of newborns per single dead adult) are equal for all strategies. In addition, the paper contains a derivation of the EESS (eco-evolutionarily stable states) conditions, describing evolutionary stability under limited population growth. We show that evolutionary stability depends on the local geometry (slopes) of the intersecting nullclines. The paper contains examples showing that density dependence induces behaviour which is not compatible with purely frequency dependent static game theoretic ESS stability conditions. We show that with the addition of density dependence, stable states can become unstable and unstable states can be stabilised. The stability or instability of the rest points can be explained by a mechanism of eco-evolutionary feedback. [ABSTRACT FROM AUTHOR]

In 2012 Broom and Rychtar developed a new framework to consider the evolution of a population over a non-homogeneous underlying structure, where fitness depends upon multiplayer interactions amongst the individuals within the population played in groups of various sizes (including one). This included the independent model, and as a special case the territorial raider model, which has been considered in a series of subsequent papers. Here individuals are based upon the vertex of a graph but move to interact with their neighbours, sometimes meeting in large groups. The most important single property of such populations is the fixation probability, the probability of a single mutant completely replacing the existing population. In a recent paper we considered the fixation probability for the Birth Death Birth (BDB) dynamics for three games, a Public Goods game, the Hawk–Dove game and for fixed fitnesses for a large number of randomly generated graphs, in particular seeing if important underlying graph properties could be used as predictors. We found two good predictors, temperature and mean group size, but some interesting and unusual features for one type of graph, Barabasi–Albert graphs. In this paper we use a regression analysis to investigate (the usual) three alternative evolutionary dynamics (BDD, DBB, DBD) in addition to the original BDB. In particular, we find that the dynamics split into two pairs, BDB/DBD and BDD/DBB, each of which give essentially the same results and found a good fit to the data using a quadratic regression involving the above two variables. Further we find that temperature is the most important predictor for the Hawk–Dove game, whilst for the Public Goods game the group size also plays a key role, and is more important than the temperature for the BDD/DBB dynamics. • A framework is used for the evolution of a population over a non-homogeneous structure. • The temperature and mean group size are good predictors for the fixation probability. • This is still true for the three other evolutionary dynamics used in this paper. • A regression analysis split the regressions into two pairs BDB/DBD and BDD/DBB. • These pairs gave essentially the same results finding a good fit to the data. [ABSTRACT FROM AUTHOR]

The world's most endangered feline species; the Iberian Lynx has suffered severe population decline and is now on the verge of extinction despite recovery plans. In this paper, an attempt has been made to understand the extinction dynamics of this endangered cat species. The paper focuses on the spread of rabbit haemorrhagic disease in the European rabbit population and its effect on the survival of the Iberian Lynx. A qualitative analysis of an eco-epidemiological model with simple law of mass action and Holling type II functional response is carried out. Existence and uniqueness of solutions are established and shown to be uniformly bounded. The basic reproduction number R 0 is obtained and the occurrence of a backward bifurcation at R 0 = 1 is shown to be possible using central manifold theory. The global stability of endemic equilibrium is established using a geometric approach. Criteria for diffusion-driven instability caused by local random movements of European rabbits and Iberian Lynx are obtained. Detailed analysis of Turing patterns formation selected by the reaction-diffusion system under zero flux boundary conditions is presented. We found that diffusion coefficients and transmission rate have appreciable influence on spatial spread of the epidemic. Numerical simulation results confirm the analytical finding and generate beautiful patterns that are consistent with the field observations and suggest that Iberian Lynx might have become extinct from Portugal and neighbouring countries. Suggestions for disease eradication and its control which in turn may increase the population of Iberian Lynx are discussed. [ABSTRACT FROM AUTHOR]

Numerical integration is a popular technique that can be successfully applied to evaluating the pest insect abundance in an agricultural field. In this paper we apply numerical integration in the problem where data about insects obtained as a result of a trapping procedure have random error (noise). We compare several methods of numerical integration that have different accuracy of evaluation when precise data are considered. In particular, we consider the composite trapezoidal and composite Simpson's rules of integration, and compare them with a statistical approach to obtaining an estimate based on the sample mean. The comparison is first done in the case when the number of traps where the data are available is large. It will be shown in the paper that noise in the data badly affects the accuracy of evaluation on fine grids of traps, so the different methods of numerical integration no longer differ in terms of their accuracy. We then consider an ecologically relevant case of a small number of traps, i.e. when the data available for evaluation are sparse. It will be discussed in the paper that the impact of noise is negligible on coarse grids of traps and therefore we can keep the accuracy hierarchy of numerical integration methods established from the consideration of precise data. We are then able to give recommendations on how to use methods of numerical integration to evaluate pest abundance. Our results are illustrated by numerical experiments. [ABSTRACT FROM AUTHOR]

Complexity has radically changed human understanding of the world environment and continues challenging our best scientific theories. In a rapidly changing research landscape, historical and philosophical insights into Complexity can heighten awareness of the proper theoretical perspectives scientists should adopt to advance the study of biocomplexity, including ecological complexity. The present work aims to deepen this awareness and disclose how researchers should generally approach, scientifically and philosophically, the question of what Complexity is, which is of great importance not only to the scientific community but also far beyond. First, this article reviews some critical historical turning points that led to Complexity. Second, the paper discusses philosophical-scientific approaches to the emergence as one of the most critical features of complex systems. The critical ideas behind attempts to understand the generators of complexity in nature are then presented, focusing on the living world. Finally, the review focuses on understanding the ecosystem- and organism-oriented perspectives of biocomplexity. We conclude that the genuine problem of the origin of complexity theory and biocomplexity will continue to inspire generations of researchers to search for new, more comprehensive mathematical and computational frameworks to explain biological hierarchies in order to further advance the scientific understanding of life. [ABSTRACT FROM AUTHOR]

Understanding dynamical behavior of a spatially distributed population is crucial to conservation and management of endangered species. This paper considers predator–prey systems with Beddington–DeAngelis functional response, where the predator moves between source–sink patches asymmetrically and acts as an agent. Our aim is to show how agent-based diffusion affects dynamics of the system and total population abundance of the species. Using dynamical systems theory, we demonstrate stability of positive equilibria in the system, which implies coexistence of the species and change of abundance by diffusion. Moreover, we show Hopf and Bautin bifurcations with multiple limit cycles, which implies multiple oscillations of populations and even extinction of species. Furthermore, this work demonstrates that diffusion in the system may lead to results reversing those without diffusion. The diffusion could change dynamics of the system between coexistence at a steady state and persistence in periodic oscillation, while evolution in asymmetry of diffusion could make the predator reach a total abundance larger than that without diffusion, even reach the maximal abundance. Our results are consistent with experimental observations and are important in studying conservation of biodiversity. • Predator-prey systems with predator's asymmetric diffusion between source–sink patches are considered. • A rigorous analysis on persistence of the system is given. • Subcritical Hopf bifurcation is used to show existence of two limit cycles and bi-stability. • Diffusion in the system could lead to results reversing those if non-diffusing. • Intermediate diffusion to the sink could make the predator reach total abundance higher than if non-diffusing. [ABSTRACT FROM AUTHOR]

• Optimal control of the hybrid variable-order fractional model of Coronavirus is presented. • Existence, uniqueness, boundedness, positivity, local and global stability of the solutions of the proposed model problem are proved. • Two control variables are considered to reduce the transmission of infection into healthy people. • Necessary conditions for the control problem are given. • Finite difference method with a hybrid variable-order operator and generalized fourth order Runge-Kutta method are used to study the optimality systems. • Stability analysis and convergence for the proposed method are proved. • Comparative studies between the obtained approximate solutions and the WHO real data for Egypt are given. • Numerical simulations are given. A novel coronavirus is a serious global issue and has a negative impact on the economy of Egypt. According to the publicly reported data, the first case of the novel corona virus in Egypt was reported on 14 February 2020. Total of 96753 cases were recorded in Egypt from the beginning of the pandemic until the eighteenth of August, where 96, 581 individuals were Egyptians and 172 were foreigners. Recently, many mathematical models have been considered to better understand coronavirus infection. Most of these models are based on classical integer-order derivatives which can not capture the fading memory and crossover behavior found in many biological phenomena. Therefore, we study the coronavirus disease in this paper by exploring the dynamics of COVID-19 infection using new variable-order fractional derivatives. This paper presents an optimal control problem of the hybrid variable-order fractional model of Coronavirus. The variable-order fractional operator is modified by an auxiliary parameter in order to satisfy the dimensional matching between the both sides of the resultant variable-order fractional equations. Existence, uniqueness, boundedness, positivity, local and global stability of the solutions are proved. Two control variables are considered to reduce the transmission of infection into healthy people. To approximate the new hybrid variable-order operator, Grünwald-Letnikov approximation is used. Finite difference method with a hybrid variable-order operator and generalized fourth order Runge-Kutta method are used to solve the optimality system. Numerical examples and comparative studies for testing the applicability of the utilized methods and to show the simplicity of these approximation approaches are presented. Moreover, by using the proposed methods we can concluded that, the model given in this paper describes well the confirmed real data given by WHO about Egypt. [ABSTRACT FROM AUTHOR]

Abstract: Obtaining reliable estimates of pest insect species abundance is an essential part of ecological monitoring programs. It is often the case that data available for obtaining such estimates are sparse which in turn makes achieving an accurate evaluation difficult. This is especially true for strongly heterogeneous pest population density distributions. In our paper we discuss the accuracy of a mean density estimate when a certain class of high aggregation density distributions is considered and a standard statistical method is employed to handle sparse sampled data. It will be shown in the paper that conventional conclusions about the accuracy of the pest population size evaluation do not work when the data are sparse and a new approach is required. Namely, if the number of traps is small, an estimate of the mean density becomes a random variable with an error of high magnitude and we have to compute the probability of an accurate estimate rather than computing the estimate itself. We have obtained a probability of an accurate estimate based on the assumption that only one trap falls within a sub-domain where the pest population density is different from zero. The probability has been calculated for the one-dimensional and the two-dimensional problem. [Copyright &y& Elsevier]

• A novel multi-scale coupled malaria transmission model is developed. • The model couples within-human and -mosquito dynamics to population level dynamics. • Feedback functions using the parasite life-history stages uniquely couples the levels. • Human host immune response leads to damping oscillations with increased biting rate. • Oscillations in the within-human model amplifies the oscillations within mosquitoes. In this paper, we developed a novel deterministic coupled model tying together the effects of within-host and population level dynamics on malaria transmission dynamics. We develop within-host and within-vector dynamic models, population level between-hosts models, and a nested coupled model combining these levels. The unique feature of this work is the way the coupling and feedback for the model use the various life stages of the malaria parasite both in the human host and the mosquito vector. Analysis of the coupled and the within-human host models indicate the existence of locally asymptotically stable infection- and parasite-free equilibria when the associated reproduction numbers are less than one. The population-level model, on the other hand, exhibits backward bifurcation, where the stable disease-free equilibrium co-exists with a stable endemic equilibrium. A global sensitivity analysis was carried out to measure the effects of the sensitivity and uncertainty in the various model parameters estimates. The results indicate that the most important parameters driving the pathogen level within an infected human are the production rate of the red blood cells from the bone marrow, the infection rate, the immunogenicity of the infected red blood cells, merozoites and gametocytes, and the immunosensitivity of the merozoites and gametocytes. The key parameters identified at the population level are the human recovery rate, the death rate of the mosquitoes, the recruitment rate of susceptible humans into the population, the mosquito biting rate, the transmission probabilities per contact in mosquitoes and in humans, and the parasite production and clearance rates in the mosquitoes. Defining the feedback functions as a linear function of the mosquito biting rate, numerical exploration of the coupled model reveals oscillations in the parasite populations within a human host in the presence of the host immune response. These oscillations dampen as the mosquito biting rate increases. We also observed that the oscillation and damping effect seen in the within-human host dynamics fed back into the population level dynamics; this in turn amplifies the oscillations in the parasite population within the mosquito-host. [ABSTRACT FROM AUTHOR]

Highlights • A mathematical model is proposed for pest control in Jatropha curcas using integrated pesticides. • Bio-pesticides are costly; require a long term process and expensive to impose. • Chemical pesticides can be introduced in the farming system along with bio-pesticide making the process faster and cost effective. • Optimal profile of both pesticides minimizes the negative effects in cost effective way. Abstract This paper presents the formulation and analysis of a mathematical model for Jatropha curcas plantation with a view to control its natural pests using application of integrated pesticides. Bio-pesticides are costly, require a long term process and expensive to impose. But if chemical pesticides are introduced in the farming system along with bio-pesticide, the process will be faster as well as cost effective. Here, we study the control of pests using integrated approach i.e. using combination of bio-pesticides and chemical pesticides. We identify the parameter for which stability switches may occur. Finally, optimal concentration profile of both pesticides have been determined using optimal control theory to minimize it negative effects and also to make the process cost effective. Numerical simulations justify the main results. [ABSTRACT FROM AUTHOR]

Highlights • This paper explores how the biomass energy flow between species and habitat loss simultaneously affect species survival. • The species providing little energy to others, receiving substantially more energy than they provide to others, or having diverse energy sources are more vulnerable to habitat loss. • The spatial structure of habitat loss determines the types of species that habitat loss has more adverse impacts on. • Although habitat loss adversely affects species survival, some species can still benefit from habitat loss. Abstract With the increasing need for animal and plant resources, not only global habitats but also the biomass energy flow between species are being damaged, and species survival is consequently subjected to increasing challenges. To address this situation, we investigated how the biomass energy flow between animal species and habitat loss simultaneously influence animal survival. The models used to explore this topic included a community model, built using a food-web model and adaptive dynamics, and habitat loss models. The simulation results suggest that (1) species providing little energy to others, receiving substantially more energy than they provide to others, or having diverse energy sources are more vulnerable to habitat loss. (2) The spatial structure of habitat loss determines the types of species that habitat loss has more adverse impacts on. For the most vulnerable species, random habitat loss is more dangerous than contagious habitat loss, while other species face more severe population reduction and lose more of their distribution area under contagious habitat loss than under random habitat loss, especially when an intermediate to significant fraction of habitat is lost. (3) Although habitat loss adversely affects species survival, some species can benefit from it, especially random habitat loss, and these species can provide intermediate levels of energy to others, both receive and provide fair amounts of energy to others, or have single energy sources. The results can help us achieve a balance between obtaining animal resources and protecting environments. [ABSTRACT FROM AUTHOR]

Highlights • Diffusive predator-prey model with prey refuge and type III response function is analyzed. • Both one and two-dimensional spatial diffusion have been considered. • Cases like sedentary prey and mobile predator or mobile prey and sedentary predator have been discussed. • Non-Turing patterns, like spiral waves, patchy structures, spot pattern, or spatiotemporal chaos may arise depending on the refuge availability and diffusion rate of species. Abstract Prey-predator interaction is one of the most commonly observed relationships in ecosystem. In the study of prey-predator models, it is frequently assumed that the changes in population densities are only time-dependent and the dynamics is generally represented by coupled nonlinear ordinary differential equations. In natural system, however, either prey or predator or both move from one place to another for various reasons. In such a case, their dynamic interaction depends both on time and space and requires coupled nonlinear partial differential equations for its dynamic representation. It is also well documented that prey refuges affect the interaction between prey and predator significantly. In this paper, we studied the dynamics of a diffusive prey-predator interaction with prey refuge and type III response function. We have considered both one and two dimensional diffusivity in the model system and presented different stability results under the assumptions that one or both species may be mobile or sedentary. Our results showed that the system may exhibit different spatiotemporal (non-Turing) patterns, like spiral waves, patchy structures, spot pattern, or even spatiotemporal chaos depending on the refuge availability and diffusion rate of species. Another interesting finding was that the dynamic complexity in a prey-predator model increases in case of mobile predator and sedentary prey compare to mobile prey and sedentary predator while refuge availability is varied. [ABSTRACT FROM AUTHOR]

Abstract: In conjunction with ecological service, in this study a definition for water eco-service is proposed, as well as a novel model designed for water eco-service assessment and compensation in a coal mining region based on the complex ecosystem theory. As a case study, the model was applied to assess the impact of coal mining on local water eco-service, economy, and society in the Mentougou District through cost–benefit analysis. A multi-compensation system that includes financial compensation, water resource supplementation and industry support, as well as capacity-building was also designed. The results show that water eco-service in the coal mining region of Mentougou has been damaged in four aspects (resource, environment, habitat, and disaster) with the damage valued at $5.54 million. It was also found that coal enterprises and both the Mentougou and Beijing governments are responsible for the multi-compensation to the damaged mining region at specific proportions and in various ways. The multi-compensation measures and schemes in both temporal and spatial scales are outlined in this paper and this study provides new theories on and methods for water ecological compensation in coal mining areas where reconstruction is needed. This paper will provide decision-making basis for policymakers. [Copyright &y& Elsevier]

Highlights • We obtain explicit bilateral estimates for biodiversity in a competition system with several resource in presence of extinctions and self-limitation effects. • We establish the global stability of solutions for systems with extinctions and large turnover rates. • In particular, we show that when the extinction threshold is not zero, the large time dynamics of the system is fundamentally non-predictable. • For a system with random parameters, we obtain estimates for the ecosystem robustness with respect to variations of resource supply which support the R * rule. Abstract We study the biodiversity problem for resource competition systems with extinctions and self-limitation effects. Our main result establishes estimates of biodiversity in terms of the fundamental parameters of the model. We also prove the global stability of solutions for systems with extinctions and large turnover rate. We show that when the extinction threshold is distinct from zero, the large time dynamics of system is fundamentally non-predictable. In the last part of the paper we obtain explicit analytical estimates of ecosystem robustness with respect to variations of resource supply which support the R * rule for a system with random parameters. [ABSTRACT FROM AUTHOR]

Highlights • The efficiency potential of simulated annealing (SA) algorithm for land resource spatial allocation (LRSA) is explored. • Our design makes the SA efficiency increased by 35% for LRSA. • The presented approach can obtain ideal solution on any location of Pareto frontier. • The approach provides a useful interactive tool for landscape spatial planning making. Abstract The primary work of formulating land use planning is to pursuit an optimized land use pattern to guide human activities for land utilization effectively. However, due to numerous spatial units and multiple land use types, as well as the spatial heterogeneity and incompatible objectives, land resource spatial optimization (LRSA) becomes a challenging issue. Currently, relevant research focuses on the exploitation of methods to enhance the efficiency of LRSA to meet the interactive demand of plan making. This paper designed a new simulated annealing (SA) algorithm for LRSA and provided an interactive platform to determine the ideal land use pattern in terms of stakeholder preferences on conflicted objectives. First, a general optimization model with three parts, including objectives, constraints and the multi-objective decision making technique, was presented. Second, for SA with crossed combinations of three cooling functions and four types of solution renewal jump steps, 12 SA sub-models were proposed, of which efficiency was compared. Lastly Jiangdu County in China was used as a case study. The following conclusions were reached: our excavation made SA efficiency for LRSA increased by about 35%, and the sub-model with logistic curve as cooling function and jump step was a gradually decreasing parameter was the most effective model; the proposed approach could obtain an ideal solution on any location of the frontier according to stakeholder preferences for conflicted objectives, thereby providing a useful interactive tool to reach an agreeable scheme transparently. [ABSTRACT FROM AUTHOR]

Highlights • Nonlinear harvesting is introduced into the predator-prey model. • Hopf bifurcation and Turing instability of the model are analyzed. • Weakly nonlinear analysis is employed to identify pattern selection. Abstract In this paper, the effect of diffusion on pattern selection in a predator-prey model with Michaelis–Menten type predator nonlinear harvesting is investigated. From the analysis of stability and bifurcation, the stability of the positive equilibrium and the occurrence conditions for the Hopf bifurcation, as well as the Turing instability, are obtained. Consequently, different patterns will occur in the system. It is necessary and imperative to derive the amplitude equations for understanding pattern selection. To this end, the multiple time scale analysis technique is employed to obtain the amplitude equations at the critical value of the Turing instability. Further, by analyzing the amplitude equations, we could identify different patterns, such as spot-like, stripe-like, hexagon-like and mixed state patterns. Finally, numerical simulations show that the rationality of the theoretical analysis and the obtained results will enrich the dynamical investigation of the predator-prey model. [ABSTRACT FROM AUTHOR]

Highlights • Model of mosaic disease of Jatropha curcas plants is proposed. • Effects of awareness-based use of nutrients and insecticides are investigated. • Awareness based on observation of infection cannot lead to eradication of disease. • Global awareness campaigns can eradicate the disease if the transmission is weak. Abstract Plant diseases are responsible for substantial and sometimes devastating economic and societal costs and thus are a major limiting factor for stable and sustainable agricultural production. Diseases of crops are particular crippling in developing countries that are heavily dependent on agriculture for food security and income. Various techniques have been developed to reduce the negative impact of plant diseases and eliminate the associated parasites, but the success of these approaches strongly depends on population awareness and the degree of engagement with disease control and prevention programs. In this paper we derive and analyse a mathematical model of mosaic disease of Jatropha curcas , an important biofuel plant, with particular emphasis on the effects of interventions in the form of nutrients and insecticides, whose use depends on the level of population awareness. Two contributions to disease awareness are considered in the model: global awareness campaigns, and awareness from observing infected plants. All steady states of the model are found, and their stability is analysed in terms of system parameters. We identify parameter regions associated with eradication of disease, stable endemic infection, and periodic oscillations in the level of infection. Analytical results are supported by numerical simulations that illustrate the behaviour of the model in different dynamical regimes. Implications of theoretical results for practical implementation of disease control are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Environmental security, as the opposite of environmental vulnerability (fragility), is multi-layered, multi-scale and complex, existing in both the objective physical, biological, and social realm, and the subjective realm of individual human perception. In this paper, we detect and quantify the scales and spatial patterns of human land use as ecosystem disturbances at different hierarchical levels in a panarchy of social–ecological landscapes (SELs) by using a conceptual framework that characterizes multi-scale disturbance patterns exhibited on satellite imagery over a four-year time period in Apulia (South Italy). In this paper we advance the measure of the functional importance of ESPs provided by natural areas and permanent cultivations based on their effectiveness at performing the services. Any landscape element contributes to the overall proportion of disturbance in the region, through its composition of disturbed locations (pixels), and to the overall disturbance connectivity through its configuration. Such landscape elements represent, in turn, functional units for assessing functional contributions of ES providers at different scale(s) of operation of the service. We assume that such effectiveness at performing the services will result directly affected by how much disturbance surrounds ESP locations at different neighborhoods. Multi-scale measurements of the composition and spatial configuration of disturbance are the basis for evaluating vulnerability of ecosystem services through multi-scale disturbance profiles concerning land-use locations where most of ecosystem service providers reside. Vulnerability estimates are derived from the identification of scale range couplings or mismatches among land-use disturbances related to different land uses and revealed by trajectories from the global profile to local spatial patterns. Scale mismatches of disturbances in space and time determine the role of land use as a disturbance source or sink, and may govern the triggering of landscape changes affecting ecosystem service providers at the scale(s) of operation of the service. The role of natural areas and permanent cultivations (olive groves and vineyards) in providing disturbance regulation across scales in South Italy has consequences for regional SELs since it may govern if and how disturbances associated with land-use intensification (sources) will affect the functional contribution of ES providers. [Copyright &y& Elsevier]

Abstract: Sustainability of ecosystem services to humanity will depend on knowledge of how ecosystems work in their natural states, which can then be carried over to managed states. The objective of this paper is to describe four properties of ecosystems taken as natural conditions to be maintained under exploitation. Three of these are design properties: near-steady-state or extremal dynamics, dominance of indirect effects, and positive utility in network organization. One is a regulatory property: distributed multivariable control. The methodology of the paper is mathematical modeling. The design properties are drawn from the inherent formalism in models. The control property is demonstrated by manipulating model parameters to achieve a management goal. The results show that: (1) natural ecosystems operate near, but not at, steady states or extrema, and ecosystems exploited for human purposes should be similarly maintained (near-steady-state imperative); (2) indirect effects are dominant in natural ecosystem networks, and should be taken into account in managing ecosystems for human benefits (nonlocal imperative); (3) natural ecosystems enhance positive relationships among their constituents, and ecosystems maintained for human services should be managed to maximize their expression of mutualistic and synergistic network properties (nonzero imperative); and (4) natural ecosystems are regulated by checks and balances distributed across many control variables in interactive networks, so that obtaining human services from ecosystems should similarly be through coordinated use of many, not few, control variables (multifactorial control imperative). The conclusion from these results is that ecosystems under natural conditions evidence organizational properties evolved over evolutionary time, and management for sustainable extraction of ecosystem services should seek to preserve and emulate these properties in the new exploited states. [ABSTRACT FROM AUTHOR]

Abstract: Despite the growing body of literature on ecosystem services, still many challenges remain to structurally integrate ecosystem services in landscape planning, management and design. This paper therefore aims to provide an overview of the challenges involved in applying ecosystem service assessment and valuation to environmental management and discuss some solutions to come to a comprehensive and practical framework. First the issue of defining and classifying ecosystem services is discussed followed by approaches to quantify and value ecosystem services. The main part of the paper is focussed on the question how to analyze trade-offs involved in land cover and land use change, including spatial analysis and dynamic modelling tools. Issues of scale are addressed, as well as the question how to determine the total economic value of different management states. Finally, developments and challenges regarding the inclusion of ecosystem services in integrative landscape planning and decision-making tools are discussed. It is concluded that the ecosystem service approach and ecosystem service valuation efforts have changed the terms of discussion on nature conservation, natural resource management, and other areas of public policy. It is now widely recognized that nature conservation and conservation management strategies do not necessarily pose a trade-off between the “environment” and “development”. Investments in conservation, restoration and sustainable ecosystem use are increasingly seen as a “win-win situation” which generates substantial ecological, social and economic benefits. [ABSTRACT FROM AUTHOR]

Abstract: As a national innovative scientific and technological facility that integrates monitoring, research and demonstrations, the Chinese Ecosystem Research Network (CERN) has become one of the largest networks in the world that consists of 40 field stations, 5 sub-centers and 1 synthesis center, covering almost all typical ecosystems in China: cropland, forest, grassland, desert, marshes, lakes, bays and urban ecosystem. Its unique features are the emphasis on understanding long-term structure and function, patterns and processes of ecosystems, combination of the inter-site comprehensive research or cross-site comparison research and the voluntary site-based exploration, and the data sharing both for domestic institutions and international networks at different levels. This paper provides a brief review of CERN by introducing its developing history, objectives and missions, summarizing its progress with the long-term ecological research in China including monitoring, scientific accomplishments in carbon cycle, ecosystem structure and functions, ecosystem restoration and data management. The paper also describes CERN''s strategic plan to 2020 and its development perspectives in the future with focus on six core thematic areas. [Copyright &y& Elsevier]

Abstract: The period-doubling route to chaos has occupied a prominent position and it is still object of great interest among the different complex phenomena observed in nonlinear dynamical systems. The reason of such interest is that such route to chaos has been observed in many physical, chemical and ecological models when they change over from simple periodic to complex aperiodic motion. In interlinked social–ecological systems (SESs) there might be an apparent great ability to cope with change and adapt if analysed only in their social dimension. However, such an adaptation may be at the expense of changes in the capacity of ecosystems to sustain the adaptation and it could affect the quality of ecosystem goods and services since it could degrade natural renewable and non-renewable resources and generate traps and breakpoints in the whole SES eventually leading to chaotic behaviour. This paper is rooted in previous results on modelling tourism-based SESs, only recently object of theoretical investigations, focusing on the dynamics of the coexistence between mass-tourists and eco-tourists. Here we describe a finer scale analysis of time-dependent regimes in the ranges of the degradation coefficient (bifurcation parameter), for which the system can exhibit coexistence. This bifurcation parameter is determined by objective changes in the real world in the quality of ecosystem goods and services together with whether and how such changes are perceived by different tourist typologies. Varying the bifurcation parameter, the dynamical system may in fact evolve toward an aperiodical dynamical state in many ways, showing that there could be different scenarios for the transition to chaos. This paper provides a further evidence for the period-doubling route to chaos with reference to tourism-based socio-ecological models, and for a period locking behaviour, where a small variation in the bifurcation parameter can lead to alternating regular and chaotic dynamics. Moreover, for many models undergoing chaos via period-doubling, it has been showed that structural perturbations with real ecological justification, may break and reverse the expected period-doublings, hence inhibiting chaos. This feature may be of a certain relevance also in the context of adaptive management of tourism-based SESs: these period-doubling reversals might in fact be used to control chaos, since they potentially act in way to suppress possibly dangerous fluctuations. [Copyright &y& Elsevier]

Abstract: GIS (Geographical Information Systems) based decision support tools will be useful in helping guide regions to sustainability. These tools need to be simple but effective at identifying, for regional managers, areas most in need of initiatives to progress sustainability. Multiple criteria analysis (MCA) has been used as a decision support tool for a wide number of applications, as it provides a systematic framework for evaluating various options. It has the potential to be used as a tool for sustainability assessment, because it can bring together the sustainability criteria from all pillars, social, economic and environmental, to give an integrated assessment of sustainability. Furthermore, the use of GIS and MCA together is an emerging addition to conducting sustainability assessments. This paper further develops a sustainability assessment framework developed for the Glenelg Hopkins Catchment Management Authority region of Victoria, Australia by providing a GIS-based decision support system for regional agencies. This tool uses multiple criteria analysis in a GIS framework to assess the sustainability of sub-catchments in the Glenelg Hopkins Catchment. The multiple criteria analysis based on economic, social and environmental indicators developed in previous stages of this project was used as the basis to build a model in ArcGIS®. The GIS-based multiple criteria analysis, called An Index of Regional Sustainability Spatial Decision Support System (AIRS SDSS), produced maps showing sub-catchment sustainability, and environmental, social and economic condition. As a result, this tool is able to highlight those sub-catchments most in need of assistance with achieving sustainability. It will also be a valuable tool for evaluation and monitoring of strategies for sustainability. This paper shows the usefulness of GIS-based multiple criteria analysis to enhance the monitoring and evaluation of sustainability at the regional to sub-catchment scale. [Copyright &y& Elsevier]

• This paper investigates the complex dynamics of a stochastic uni-directional consumer-resource mutualism system. • We establish sufficient conditions for the extinction and persistence in mean of the resource, the consumer or the entire system. • In the case of extinction of one species, we give the density function of the other species. • We discuss the stochastically ultimate boundedness and stochastic permanence. • We establish sufficient conditions for the existence of an ergodic stationary distribution to the system. Like predation and competition, mutualism is recognized as a consumer-resource interaction, which includes bi-directional and uni-directional mutualisms. In this paper, we firstly propose a stochastic uni-directional consumer-resource system of two species in which the consumer has both positive and negative effects on the resource, while the resource has only a positive effect on the consumer. We then mathematically analyze the system, to demonstrate the existence, uniqueness, asymptotic pathwise behavior and stochastically ultimately boundedness of the global positive solution, and to establish sufficient conditions for the global attractivity and the existence of ergodic stationary distribution of the system. We also establish sufficient conditions for the extinction and persistence in mean of the resource, the consumer or the entire system. Numerical simulations are carried out to demonstrate the analytical results. [ABSTRACT FROM AUTHOR]

Abstract: We address the three main issues raised by Stirling et al. [Stirling, I., Derocher, A.E., Gough, W.A., Rode, K., in press. Response to Dyck et al. (2007) on polar bears and climate change in western Hudson Bay. Ecol. Complexity]: (1) evidence of the role of climate warming in affecting the western Hudson Bay polar bear population, (2) responses to suggested importance of human–polar bear interactions, and (3) limitations on polar bear adaptation to projected climate change. We assert that our original paper did not provide any “alternative explanations [that] are largely unsupported by the data” or misrepresent the original claims by Stirling et al. [Stirling, I., Lunn, N.J., Iacozza, I., 1999. Long-term trends in the population ecology of polar bears in western Hudson Bay in relation to climate change. Arctic 52, 294–306], Derocher et al. [Derocher, A.E., Lunn, N.J., Stirling, I., 2004. Polar bears in a warming climate. Integr. Comp. Biol. 44, 163–176], and other peer-approved papers authored by Stirling and colleagues. In sharp contrast, we show that the conclusion of Stirling et al. [Stirling, I., Derocher, A.E., Gough, W.A., Rode, K., in press. Response to Dyck et al. (2007) on polar bears and climate change in western Hudson Bay. Ecol. Complexity] – suggesting warming temperatures (and other related climatic changes) are the predominant determinant of polar bear population status, not only in western Hudson (WH) Bay but also for populations elsewhere in the Arctic – is unsupportable by the current scientific evidence. The commentary by Stirling et al. [Stirling, I., Derocher, A.E., Gough, W.A., Rode, K., in press. Response to Dyck et al. (2007) on polar bears and climate change in western Hudson Bay. Ecol. Complexity] is an example of uni-dimensional, or reductionist thinking, which is not useful when assessing effects of climate change on complex ecosystems. Polar bears of WH are exposed to a multitude of environmental perturbations including human interference and factors (e.g., unknown seal population size, possible competition with polar bears from other populations) such that isolation of any single variable as the certain root cause (i.e., climate change in the form of warming spring air temperatures), without recognizing confounding interactions, is imprudent, unjustified and of questionable scientific utility. Dyck et al. [Dyck, M.G., Soon, W., Baydack, R.K., Legates, D.R., Baliunas, S., Ball, T.F., Hancock, L.O., 2007. Polar bears of western Hudson Bay and climate change: Are warming spring air temperatures the “ultimate” survival control factor? Ecol. Complexity, 4, 73–84. doi:10.1016/j.ecocom.2007.03.002] agree that some polar bear populations may be negatively impacted by future environmental changes; but an oversimplification of the complex ecosystem interactions (of which humans are a part) may not be beneficial in studying external effects on polar bears. Science evolves through questioning and proposing hypotheses that can be critically tested, in the absence of which, as Krebs and Borteaux [Krebs, C.J., Berteaux, D., 2006. Problems and pitfalls in relating climate variability to population dynamics. Clim. Res. 32, 143–149] observe, “we will be little more than storytellers.” [Copyright &y& Elsevier]

Abstract: Building on Aristotle''s distinction between oikonomía (‘the art of household management’) and chrematistics (khrēmatistiké, ‘the art of acquisition’) and the associated difference between use-value and exchange-value based economic processes this paper critically discusses modern economics by employing system theory insights. It is argued that the constitution of modern economics has been, at the political and ideological level, strongly associated to the rise of capitalist free-market economy, while at the methodological level it is based on the Newtonian ideals of formal elegance and simplicity of models. These Newtonian ideals in turn underpin the universal claim of modern economics’ theories and the presumption of causal relations between objects that respond in a fully determinable mechanical way to outside stimuli. Discussing the link between modern economics methodological claims at one hand and its political/ideological legitimization of the free-market institutional arrangement of the economic process at the other, in the final part of this paper both modern economics and the free-market dynamics are discussed from the perspective of dynamic complex system''s theory. [Copyright &y& Elsevier]

Abstract: This paper discusses the epistemological predicament associated with the formal modeling of the behavior of complex adaptive systems. This is a class of systems which: (i) express functions and structures on multiple levels and scales; and (ii) become “something different” in time, because of evolution. The paper addresses four points. (#1) The pre-analytical definition of “what is observed and how” is essential in determining any quantitative output of mathematical models. Scientists have to learn how to acknowledge and to deal better with the fact that the observer always affects what is observed when defining the descriptive domain. This influence of the observer occurs even before there is interaction with the observed in the process of gathering empirical data. (#2) The peculiar human ability to share a commensurate experience involves the concept of semiotic identity. The generation of knowledge is possible only because of the co-existence of a semiotic reality and physical systems. (#3) The special organization of living systems depends on their ability to establish and maintain a semiotic coupling between functional and structural types. This coupling is associated with the concept of holon and explains why it is impossible to formalize in substantive terms organizations recognized as holons. Holons can only be handled in semiotic terms. (#4) A strong semiotic identity entails an uncontested selection of an appropriate sampling procedure for validating the choice of the formal identity used in the model. On the contrary, a weak semiotic identity entails a tautology in the modeling relation. The formal identity used to represent the semiotic identity in the model has also to be used to decide about the relative sampling used for validation. The distinction between strong and weak semiotic identities places a limit on the power of modeling. A sound modeling relation requires strong semiotic identities, whereas the typical issues associated with science for governance imply perceptions and representations based on weak semiotic identities. [Copyright &y& Elsevier]

Abstract: This paper presents in a synthetic way, a complex systems perspective on sustainability that highlights systems integrity and ethical integrity as complements. Sustainability is characterised as coevolution of economic, social and environmental systems respecting a dynamic “triple bottom line”—the simultaneous satisfaction of quality/performance goals pertaining to each of the three spheres. The theme of system regulation and governance leads to demarcation of a fourth fundamental category of organisation, the political sphere whose role is regulation of the economic and social spheres and thus of relations with (and within) the environmental sphere. Perspectives for the application of this “Tetrahedral Model” in sustainability science and policy analyses are outlined, relating to the “four capitals” and to the question of monetary evaluation of changes in social and environmental domains. The paper concludes by making a link between the triple bottom line, complexity and deliberation in sustainability politics. [Copyright &y& Elsevier]

Abstract: In this paper, a new model of phytoplankton growth in the chemostat is proposed. First, we give a description of the chemostat and we recall the main models: the simple Monod model, experimentally validated for bacteria growth and the Droop model, which is validated for phytoplankton growth and takes into account the possible nutrient storage. Though our model is quite similar to the Droop one, our approach is based on biochemical mechanisms and not on empirical observations. We study two versions of the model: one taking into account cell mortality; the other not. The main result is the global asymptotic stability of the equilibrium, ensuring survival of the cells under some hypotheses. The paper ends with some illustrative simulations and a comparison with the dynamic energy budget modelling approach. [Copyright &y& Elsevier]

Current developments in ecosystem theory to understand ecological complexity, particularly those incorporating and applying thermodynamic principles, are making it possible to integrate various ecosystem approaches into a consistent theoretical framework. The time, therefore, seems right to apply this theory to explain observations published in the ecological literature that typically lack linkages to ecological theory or other rule-based explanations. This paper presents the foundations of that theory of ecological complexity in eight observational principles and summarizes the results from a review of a number of papers using thermodynamic principles to explain ecological observations. The theory will continue to evolve and be modified as more test cases are made, however, here explanations of some published ecological observations are presented to illustrate how the ecosystem theory is applied. [Copyright &y& Elsevier]

• Ecological sustainable partitioning of metapopulations networks. • Network topology and the metapopulations stability. • Ensuring stability in the partitioned subnetworks. • Computational algorithm for partitioning the patched ecological networks. • Strategy toward minimizing human-induced habitat destruction. Ecological complex networks are common in the study of patched ecological systems where evolving populations interact within and among the patches. The loss of the dispersal connections between patches due to reasons such as erosion of migration corridors and road construction can cause an undesirable partitioning of such networks resulting in instability or negative impact on the metapopulations. A partitioning or spatial cut that is aware of the stability of the dynamics in the resulting daughter sub-networks can be an effective tool in dealing with the situation like proposing road alignment through a metapopulations network. This paper provides some mathematical conditions along with an heuristic graph partitioning algorithm that can help in finding ecologically suitable partitions of the metapopulations networks. Our study noted the crucial role of network connectivity (measured by Fiedler value) in stabilizing the metapopulations. That is, a sufficiently connected metapopulations network along with constrained internal patch dynamics has stable dynamics around its homogeneous co-existential equilibrium solution. With the considered mathematical model in this paper, network partitioning does not alter the internal patch dynamics around its homogeneous equilibrium point, but it can change the connectivity levels in the partitioned subnetworks. Thus, the proposed partitioning problem for an already stable metapopulations network is reduced to finding its subnetworks with desirable connectivity levels. [ABSTRACT FROM AUTHOR]

Highlights • Robert Rosen said that ecosystems are chimeras with their own genotype and phenotype. • Chimera members provide functions to each other that they cannot do for themselves. • Loop analysis of a marine plankton community illustrates how chimeras could work. • A thought experiment is used to explore ecosystem chimeran problems and solutions. • Evolution: The Complexity Synthesis should replace Evolution: The Modern/Extended Synthesis. Abstract Robert Rosen wrote an interesting paper entitled, “Cooperation and Chimera” in which he explained how living systems or their parts often combine with those of others to create chimeran individuals with new genotypes, phenotypes, and environments. He concluded that these relationships are mainly cooperative in that the partners provide functional capabilities to each other that the recipients cannot provide for themselves. Rosen developed his concept of chimeras within the broader areas of Rosennean Complexity and Relational Biology, providing insights into notions of purpose, function, causality, survival, persistence, and complexity. Chimeras are ubiquitous and occur throughout the biological hierarchy. At the ecosystem level, chimeras can be formed when the member populations are organized into functional groups such as the nodes of a food web, and they interact with each other through environmental modifications that feedback to change phenotypes and genotypes, and form a new individual with a purpose: ecological survival and evolutionary persistence. Thus, ecosystems are Rosennean Complex (RC) chimeras. This concept is applied to the Narragansett Bay plankton food web using loop analysis. Then a Thought Experiment involving Mother Nature is employed to illustrate how being a Rosennean Complex chimera helps the food web solve three critical problems: securing matter and energy, which is a priori necessary for all open systems; maintaining functional and modular integrity as a chimeran individual; and manipulating time especially using feedforward and anticipation – none of these functions could be accomplished by a single ecosystem member. In ecology, Rosen's chimeras are closest to the concept of niche construction, however, since niche is a population-level concept, based largely on physiology and environmental factors, it is impossible to extrapolate niche construction to ecosystem chimera construction. The parts do not reveal the whole in complex systems. Rosennean Complex ‘chimera construction’ approaches should be used at the ecosystem level while retaining ‘niche construction’ at the population level. In evolution, the areas of symbiogenesis and coevolution align with chimeran concepts to provide adaptive advantages and opportunities not available with gene-centred individual and population-based fitness concepts. Evolutionary success for the ecosystem as a selection unit involves more than a collection of genes, and fitness is more than changes in gene frequencies. Ecological survival and persistence necessitate chimerization and the formation of new cooperative ecosystemic individuals. This study concludes that a paradigm shift is needed from Evolution: The Modern/Extended Synthesis to Evolution: The Complexity Synthesis. [ABSTRACT FROM AUTHOR]

Species competition in a fluctuating environment is often modelled with stochastic reaction-diffusion equations. In most cases the movement of individuals is described as Fickian diffusion. However, in heterogeneous environments this is not the first choice. Recently, it has been shown that Fokker-Planck diffusion describes the movement of species in a more realistic way. Fickian diffusion always leads to spatially uniform stationary distributions whereas the Fokker-Planck diffusion generates nonuniform solutions according to the heterogeneity of the environment and the corresponding spatial variation of diffusion. Species accumulate in regions of low diffusivity and tend to lower their densities in areas of high diffusivity. In the present paper, the impact of Fokker-Planck diffusion is studied with particular consideration of changing spatio-temporal population patterns during the competitive invasion of a spatially heterogeneous, populated habitat. The standard Lotka-Volterra competition model is applied to describe the resident-invader interaction. The resident is assumed to be adapted to the heterogeneous living conditions, i.e., its motion is modelled as space-dependent Fokker-Planck diffusion. The invader's diffusion is taken as neutral Fickian. Furthermore, it is shown that multiplicative environmental noise can either foster or hinder the invasion. [ABSTRACT FROM AUTHOR]

In this paper, I propose a new evenness-based method for calculating plot-to-plot (dis)similarity coefficients. The method is very flexible, as (dis)similarity can be calculated for any kind of species abundance data (also including functional or phylogenetic differences between species), and can be easily generalized to multiple sites. To show how the proposed method works in practice, the behavior of two similarity coefficients based on Pielou's and Williams’ evenness is examined with simulated data representing an ideal ecological gradient. Being derived from classical evenness indices, which have been used in ecology for decades, this new family of measures has a great potential for future research in community ecology and multivariate analysis. [ABSTRACT FROM AUTHOR]

Animal search patterns are governed by the various movement strategies undertaken when animals encounter stimuli. The stimuli caused by resource growth and depletion can modify search patterns due to the need to finding resources. In this paper, we investigate the influence of resource depletion on the dynamics of dispersal of a population which is related to diffusion or anomalous diffusion. Our approach is to develop a population level model using partial differential equations that takes into account rules for movement based on the resource levels. Through numerical analysis, we show that the population dispersal patterns depend on the resource depletion, with superdiffusive spread in cases where the depletion rate (as given by high consumption and low replenishment) is high. This has the potential to increase searching efficiency. [ABSTRACT FROM AUTHOR]

Patterns and rates of invasive species spread have been a focus of attention for several decades. Majority of studies focused on the species proliferation in a relatively uniform “open space” thus leaving aside the effects of the landscape geometry as given by size and shape of inaccessible areas. In this paper, we address this issue by considering the spatiotemporal dynamics of an alien species in a domain where two large uniform habitats are connected by a narrow corridor. We consider the case where the species is originally introduced into one of the habitats but not to the other. The alien species is assumed to be affected by a predator, so that mathematically our system consists of two coupled diffusion–reaction equations. We show that the corridor tends to slow down the spread: it takes the alien population an extra time to penetrate through the corridor, and this delay time can be significant in the case of patchy spread. We also show that a sufficiently narrow corridor blocks the spread; simple analytical estimates for the critical width of the corridor are obtained. Finally, we show that the corridor can become a refuge for the alien population. If considered on a longer timescale that includes species adaptation and/or climate change, the corridor may then become a source of a secondary invasion. [ABSTRACT FROM AUTHOR]

We consider a two-trophic ecological model comprising of two predators competing for their common prey. We cast the model into the framework of a singular perturbed system of equations in one fast variable (prey population density) and two slow variables (predator population densities), mimicking the common observation that the per-capita productivity rate decreases from bottom to top along the trophic levels in Nature. We assume that both predators exhibit Holling II functional response with one of the predators (territorial) having a density dependent mortality rate. Depending on the system parameters, the model exhibits small, intermediate and/or large fluctuations in the population densities. The large fluctuations correspond to periodic population outbreaks followed by collapses (commonly known as cycles of “boom and bust”). The small fluctuations arise due to a singular Hopf bifurcation in the system, and are ecologically more desirable. However, more interestingly, the system exhibits mixed-mode oscillations (which are concatenations of the large amplitude oscillations and the small amplitude oscillations) that indicate the adaptability of the species to prolong the time gap between successive cycles of boom and bust. Numerical simulations are carried out to demonstrate the extreme sensitivity of the system to initial conditions (chaos and bistability of limit cycles are observed) as well as to the system parameters (here we only show the sensitivity to the density dependent mortality rate of the territorial predator). This model throws light at the uncertainties in long term behaviors that are associated with a real ecological system. We show that even very small changes in the system parameters due to natural or human-induced causes can lead to a complete different ecological phenomenon, thus affecting the predictability of the density of the prey population. In this paper, we explain the mechanisms behind the irregular fluctuations in the population sizes in an attempt to understand the dynamics occurring in a natural population and also comment on the inherent uncertainties associated with the system. [ABSTRACT FROM AUTHOR]

Debris-covered glaciers are glaciers with the largest part of the ablation zone covered by a debris layer. Recent papers showed that debris-covered glaciers are able to support plant and arthropod life, advancing the hypothesis that such landforms could act as warm-stage refugia for cold-adapted species due to their microclimate features and thermal inertia. However, integrated research comparing debris-covered glaciers with surrounding landforms to outline their ecological peculiarities are currently lacking. We analyze some abiotic (glacier surface velocity, ice melting rate and supraglacial debris thickness; ground temperature and humidity; substrate physical and chemical parameters) and biotic features (vascular plant and arthropod communities) of an Alpine debris-covered glacier (Belvedere, Western Alps, Italy), and compare them with those of the surrounding iceless landforms as reference sites (stable slope and iceless moraine). Our data show remarkable differences between stable slopes and unstable landforms as a whole (iceless moraine and supraglacial debris). The iceless moraine and the supraglacial debris show similar substrate features, but different ground temperature (lower on supraglacial debris) and different occurrence of cold-adapted species (more frequent/abundant on supraglacial debris). Such differences could be attributed to the thermal effect of underlying ice. Our data support the hypothesis advanced by previous studies: the thermal contrast with the surrounding landforms and the ability to descend below the climatic treeline give debris-covered glaciers the ecological requirements to be considered potential warm-stage refugia for cold-adapted species. However, our data highlighted that biotic colonization of such landforms could be prevented by some glaciological features, like the mechanical disturbance due to the ordinary ice dynamics (e.g. high glacier surface velocity) and time since the last extraordinary ice dynamic (e.g. surge-type movements). The combined effect of such features is currently preventing colonization by low-dispersal taxa as some cold-adapted ground beetles. [ABSTRACT FROM AUTHOR]

Global mean sea level has been rising in response to global warming since the past few decades and is anticipated to potentially affect the coastal population. The main driver of global warming is the enhanced concentration of the heat-trapping gas carbon dioxide in the atmosphere. In this paper, we propose a nonlinear mathematical model to study the effect of an increase in the anthropogenic carbon dioxide emissions on sea level rise and its effect on the human population. The long-term behavior of the proposed system is analyzed using stability theory of differential equations. The model analysis shows that an increase in the anthropogenic emission rate of carbon dioxide leads to increase in the equilibrium levels of surface temperature and sea water level. Further, it is found that the increase in anthropogenic emission rate of carbon dioxide and melting rate of ice sheets lead to decrease in the equilibrium level of human population as a result of crowding caused by the decrease in the total inhabitable land area due to sea level rise. Numerical simulations are carried out to illustrate the effect of key parameters on the dynamics of the system. [ABSTRACT FROM AUTHOR]

The most common threats to wetlands and the Keoladeo National Park are water scarcity, changing biodiversity, increasing rate of contamination, uncontrolled growth of grass, urbanization and human intervention. In this paper, an attempt has been made to study the degradation and conservation of biotic part of the park through a reaction diffusion modeling. The biotic part of wetland is divided into three categories good biomass, bad biomass, and bird population. Good biomasses are those species that provide food for bird population and contain floating vegetation, fishses, waterfowl and useful species. Bad biomasses contain Paspalum distichum and its family that affect the growth of good biomass. The interaction between good biomass and bird population is considered to be Crowley–Martin type functional response. We have presented the theoretical analysis of stability and Turing instability. With the help of numerical simulations, we have observed spatial patterns for the wetland model system. This study demonstrates that spatial heterogeneity, diffusion coefficients and per capita availability of water to bad biomass play an important role on the dynamical behavior of the model system. Also, we have pointed out the parameters that are responsible for the bad health of wetland ecosystem and suggested enhancing the water supply, decontamination and optimizing the land use structure for sustaining ecological balance and socio-economic stability of a region. [ABSTRACT FROM AUTHOR]

In this paper, in view of the senescence of plant and the decay of wrack, time delays are introduced into the plant-wrack model. The effects of wrack decay and time delay on the dynamical behaviors of the diffusive plant-wrack model are studied analytically and numerically. When the delay is zero, the wrack decay will induce the change of stability of the unique equilibrium point, further lead to the occurrence of the Hopf bifurcation and the Turing instability. When the delay is present, the conditions for the occurrence of the Hopf bifurcation are established. By comparing the results of the model without and with delay, it is found that the increases of delay may induce no stability switches, a single stability switch or multiple stability switches, when the value of wrack decay can stabilize model with zero delay. When the value of wrack decay can destabilize model with zero delay, numerical simulations show that the small delay may cause homogeneous distributions of vegetation, while the larger delay may cause the emergence of periodic oscillation of vegetation. The obtained results provide a basis for understanding the spatiotemporal evolution of such a plant-wrack model with delay. • Plant-wrack model with delay is proposed. • Effects of wrack decay and delay are analyzed. • Complex dynamics are presented. [ABSTRACT FROM AUTHOR]

Abstract: The international conference “Models in Population Dynamics and Ecology 2012” (MPDE’12) was held at the Federal University of Santa Maria, Brazil, from 10 to 13 September, 2012. MPDE’12 consisted of 9 keynote talks, 3 mini-symposia, 30 contributed talks and 23 posters and gathered about 100 participants from 10 different countries of the Americas and Europe. The meeting explored a wide spectrum of topics such as biological invasions and spread of epidemics, behavioral ecology, collective dynamics, individual animal movement, ecological pattern formation, evolutionary dynamics, epidemiology and eco-epidemiology. This special issue of Ecological Complexity consists of 9 carefully selected papers presented at the conference. Here, we highlight some of the new findings and results of these papers. [Copyright &y& Elsevier]