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Nonliving resources frequently flow across ecosystem boundaries, which can yield networks of spatially coupled ecosystems. Yet the significance of resource flows for ecosystem function has predominantly been understood by studying two or a few coupled ecosystems, overlooking the broader resource flow network and its spatial structure. Here, we investigate how the spatial structure of larger resource flow networks influences ecosystem function at metaecosystem scales by analyzing metaecosystem models with homogeneously versus heterogeneously distributed resource flow networks but otherwise identical characteristics. We show that metaecosystem function can differ strongly between metaecosystems with contrasting resource flow networks. Differences in function generally arise through the scaling up of nonlinear local processes interacting with spatial variation in local dynamics, the latter of which is influenced by network structure. However, we find that neither network structure guarantees the greatest metaecosystem function. Rather, biotic (organism traits) and abiotic (resource flow rates) properties interact with network structure to determine which yields greater metaecosystem function. Our findings suggest that the spatial structure of resource flow networks coupling ecosystems can be a driver of ecosystem function at landscape scales. Furthermore, our study demonstrates how modifications to the structural, biotic, or abiotic properties of metaecosystem networks can have nontrivial large-scale effects on ecosystem function. [ABSTRACT FROM AUTHOR]

Rural and rural-urban linkages are in terms of different flows that give the spatial structure of the regions a known entity. Therefore, in the past few decades, we have seen the attention of planners to the network approach and the basic interaction between different points and topics. Considering the importance of this issue, the aim of the current research is to investigate the relationship between rural settlements and the city of Shaft located in Jirdeh in the central part of Shaft with a network analysis approach. The research method is a descriptive-analytical type, which was carried out by a survey method. The statistical population consisted of 33 villagers, members of the Islamic Council of the villages of Jiredeh and Shaft, and a matrix questionnaire was implemented in order to measure the relationships between them. Also, the theory and model of network analysis using Ucinet software and tests of density, degree, ambidexterity, transferability, E-I, etc. have been used to analyze the data and various graphs have been used to show relationships. The results show that there is little network cohesion and cooperation between the studied villages at the village level. The low level of the density index at the level of the network or two-way shows that there are few relationships and most of the flows are one-way and towards the city of the shaft. [ABSTRACT FROM AUTHOR]

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Nowadays, changes in food consumption patterns due to urbanization, increasing per capita consumption, economic growth and the move from local to global in the consumer markets necessitate ensuring food security for different countries, especially developing ones. This study investigates the impact of rural-urban linkages affected by spatial flows on food security. The present research method is quantitative and has been conducted by employing a descriptive-analytical method. The research population consisted of households in peri-urban villages of Dehdasht. Twenty one villages were randomly selected using Cochran's formula. 358 households were randomly selected from 3538 households using Cochran's formula. Correlation and regression analysis were conducted using SPSS to analyze the collected data. In addition, the structural equation model (SEM) of partial least squares regression (PLS) method was applied using SMART PLS 3. The results indicate that rural-urban linkages affected by spatial flows (independent variable) with a T value of 27.678 and a path coefficient of 0.745 have a positive effect on food security (dependent variable). Moreover, the results of multivariate linear regression showed that the social linkage and the economic linkage variable with the values 0.509 and 0.151 respectively had the greatest and the least impact on food security. [ABSTRACT FROM AUTHOR]

Ecosystems are linked to neighbouring ecosystems not only by dispersal, but also by the movement of subsidy. Such subsidy couplings between ecosystems have important landscape-scale implications because perturbations in one ecosystem may affect community structure and functioning in neighbouring ecosystems via increased/decreased subsidies. Here, we combine a general theoretical approach based on harvesting theory and a two-patch protist meta-ecosystem experiment to test the effect of regional perturbations on local community dynamics. We first characterized the relationship between the perturbation regime and local population demography on detritus production using a mathematical model. We then experimentally simulated a perturbation gradient affecting connected ecosystems simultaneously, thus altering cross-ecosystem subsidy exchanges. We demonstrate that the perturbation regime can interact with local population dynamics to trigger unexpected temporal variations in subsidy pulses from one ecosystem to another. High perturbation intensity initially led to the highest level of subsidy flows; however, the level of perturbation interacted with population dynamics to generate a crash in subsidy exchange over time. Both theoretical and experimental results show that a perturbation regime interacting with local community dynamics can induce a collapse in population levels for recipient ecosystems. These results call for integrative management of human-altered landscapes that takes into account regional dynamics of both species and resource flows. [ABSTRACT FROM AUTHOR]

Some fifty years in the development of ideas about the definition and use of functional regions are elaborated in this article, as an introduction to this Special Issue of the Moravian Geographical Reports. The conceptual basis for functional regions is discussed, initially in relation to region-organising interactions and their behavioural foundations. This paper presents an approach to functional regions which presumes that such regions objectively exist and that they are based on more or less tangible processes (however, a different view of regions is also briefly described). A typology of functional regions is presented and the development of methods for finding a definition of functional regions is discussed, as well as a typology for these methods. The final part of this article stresses the importance of functional regions in geographical research, and introduces some emerging new prospects in the study of functional regions. [ABSTRACT FROM AUTHOR]

As societal demand for food, water and other life-sustaining resources grows, the science of ecosystem services (ES) is seen as a promising tool to improve our understanding, and ultimately the management, of increasingly uncertain supplies of critical goods provided or supported by natural ecosystems. This promise, however, is tempered by a relatively primitive understanding of the complex systems supporting ES, which as a result are often quantified as static resources rather than as the dynamic expression of human-natural systems. This article attempts to pinpoint the minimum level of detail that ES science needs to achieve in order to usefully inform the debate on environmental securities, and discusses both the state of the art and recent methodological developments in ES in this light. We briefly review the field of ES accounting methods and list some desiderata that we deem necessary, reachable and relevant to address environmental securities through an improved science of ES. We then discuss a methodological innovation that, while only addressing these needs partially, can improve our understanding of ES dynamics in data-scarce situations. The methodology is illustrated and discussed through an application related to water security in the semi-arid landscape of the Great Ruaha river of Tanzania. [ABSTRACT FROM AUTHOR]

n algorithm is proposed for calculating the parameters of weak shock waves at large distances from their origination. In chosen meridional planes, the parameters of the near field of the three-dimensional flow are used to determine the streamwise coordinates of 'phantom bodies' by linear relations. When the initial body is replaced by a system of 'phantom bodies' for which discrete values of the Whitham function are found, the far-field parameters are calculated by the Whitham theory, independently in each meridional plane. Results calculated for a body with axial symmetry and for bodies with spatial symmetry are presented. [ABSTRACT FROM AUTHOR]

Despite a recent emphasis on understanding cross-habitat interactions, few studies have examined the ecological linkages between lakes and surrounding terrestrial habitats. The current paradigm of land–lake interactions is typically unidirectional: the view is that nutrients and matter are transported downslope from the surrounding watershed to their ultimate lacustrine destination. Emergent aquatic insects, which spend their larval stages in lake sediments and emerge as adults to mate over land, can act as vectors of material, energy and nutrients from aquatic to terrestrial habitats. In this study, we document a gradient of midge (Diptera: Chironomidae) infall rates into terrestrial habitats (measured as g dw midges m−2 d−1) surrounding eight lakes in Northern Iceland (≈66°N latitude). Lakes ranged from having virtually no midge infall (for example, Helluvaðstjörn, 0.03 g m−2 d−1) to extreme levels (for example, Mývatn, 19 g m−2 d−1) with abundances of midges decreasing logarithmically with distance from shore. Annual midge input rates are estimated as high as 1200–2500 kg midges ha−1 y−1. As midges are approximately 9.2% total N, this can result in a significant fertilization effect of terrestrial habitats with consequences for plant quality and community structure. In addition, we used naturally-occurring δ13C and δ15N isotopes to examine food web structure and diet sources of terrestrial arthropod consumers surrounding lakes with differing amounts of midge input. Terrestrial arthropods showed increased utilization of aquatic-derived (that is, midge) C relative to terrestrial sources as midge infall increased. This pattern was particularly pronounced for predators, such as spiders and opiliones, and some detritivores (Collembola). These findings suggest that, despite being largely ignored, aquatic-to-terrestrial linkages can be large and midges can fuel terrestrial communities by directly serving as resources for predators and decomposers. [ABSTRACT FROM AUTHOR]

Spatial flows of materials and organisms across ecosystem boundaries are ubiquitous. Understanding the consequences of these flows should be a basic goal of ecosystem science, and yet it has received scant theoretical treatment to date. Here, using a simple, open, nutrient-limited ecosystem model with trophic interactions, we explore theoretically how spatial flows affect the functioning of local ecosystems, how physical mass-balance constraints interact with biological demographic constraints in the regulation of this functioning, and how failure to consider these constraints explicitly can lead to models that are ecologically inconsistent. In particular, we show that standard prey-dependent models for trophic interactions may lead to implausible outcomes when embedded in an ecosystem context with appropriate mass flows and mass-balance constraints. Our analysis emphasizes the need for integration of population, community, and ecosystem perspectives in ecology and the critical consequences of assuming closed versus open systems.

Ecologists increasingly recognize that a consideration of spatial dynamics is essential for resolving many classical problems in community ecology. In the present paper, I argue that understanding how trophic interactions influence population stability can have important implications for the expression of spatial processes. I use two examples to illustrate this point. The first example has to do with spatial determinants of food chain length. Prior theoretical and empirical work has suggested that colonization–extinction dynamics can influence food chain length, at least for specialist consumers. I briefly review evidence and prior theory that food chain length is sensitive to area. A metacommunity scenario, in which each of various patches can have a food chain varying in length (but in which a consumer is not present on a patch unless its required resource is also present), shows that alternative landscape states are possible. This possibility arises if top predators moderate unstable interactions between intermediate predators and basal resources. The second example has to do with the impact of recurrent immigration on the stability of persistent populations. Immigration can either stabilize or destabilize local population dynamics. Moreover, an increase in immigration can decrease average population size for unstable populations with direct density-dependence, or in predator–prey systems with saturating functional responses. These theoretical models suggest that the interplay of temporal variation and spatial fluxes can lead to novel qualitative phenomena. [ABSTRACT FROM AUTHOR]