Using circuit theory to model connectivity in ecology, evolution, and conservation brad h. Calabrese and fagan, 2004 distance between patches euclidean distance or minimum cost path link node habitat suitable patch graph landscape graph theory landscape ecology the ecological application of graph theory showed to be an. Harary graph super a,deat landscape connectivity subdivision of harary graph graph order p graph size graph structures have been exposed to be a dominant and helpful way of modeling landscape networks. Graph theory can use both structural and dispersal data unify multiple aspects of habitat connectivity can be applied at patch or landscape levels many graph. Connectivity, conservation priorities, corridors, graph theory, habitat fragmentation, habitat loss, landscape metrics, landscape planning, patches, spatial indices abstract the. The use of graph theory has been widely used in landscape ecology to identify. Harary graph super a,deat landscape connectivity subdivision of harary graph graph order p graph size graph structures have been exposed to be a dominant and helpful way of modeling. In doing so we demonstrate the utility of a mathematical graph as an ecological construct with respect to habitat connectivity. Original research role of graph theory to facilitate. The ecological application of graph theory showed to be an effective way to analyze the landscape.
Integrating landscape connectivity and habitat suitability to. In graph theory, an orientation of an undirected graph is an assignment of a direction to each edge, turning the initial graph into a directed graph. We know that contains at least two pendant vertices. Third, the design of landscape graphs and the resulting calculation of connectivity metrics allowed mapping the impact of the highway on multispecies ecological connectivity. Some of studies show that a gisbased approach is used to quantify landscape. Landscape connectivity allows for the identification of the ecologically interconnected network of landscape elements. Landscape connectivity is characterized by graph making with to base on gis. Consequently, several studies apply graph theory to landscape connectivity networks to represent and analyze the connection between landscape spatial structure and species dispersal bunn. Connectedness an undirected graph is connected iff for every pair of vertices, there is a path containing them a directed graph is strongly connected iff it satisfies the above condition for. A graphtheory framework for evaluating landscape connectivity. Edges may or may not be interconnected and deliver information about connectivity 18.
Landscape connectivity in ecology is, broadly, the degree to which the landscape facilitates or impedes movement among resource patches. Thus, there is an increasing interest in considering connectivity in landscape planning and habitat conservation. This approach can be applied easily to assessing habitat connectivity in any fragmented or patchy landscape. A conservation application of graph theory we use focalspecies analysis to apply a graphtheoretic approach to landscape connectivity in the coastal plain. A framework to optimize biodiversity restoration efforts. It includes new advances in quantifying landscape structure and connectivity such as graph theory, as well as labs that incorporate the latest scientific understanding of ecosystem. Shah4 1national center for ecological analysis and synthesis, santa barbara, california 93101 usa.
Similar applications of graph theory have emphasised the importance of structural landscape connectivity on the species richness pattern of amphibian assemblages. Circuit theory and modelbased inference for landscape connectivity 23 figure 1. Graph theory provides a simple solution for unifying and evaluating multiple aspects of habitat connectivity, can be applied at the patch and landscape levels, and can quantify either structural or functional connectivity. Graph theory is well developed in other fields, including geography transportation networks, routing applications, siting problems and computer science circuitry and network optimization. This work focuses on mapping landscape connectivity by making use of a subdivision of a harary graph through super edge antimagic total. Using circuit theory to model connectivity in ecology. Jan 01, 2001 graph theory is well developed in other fields, including geography transportation networks, routing applications, siting problems and computer science circuitry and network optimization. Alternatively, connectivity may be a continuous property of the landscape and independent of patches and paths. Calabrese and fagan, 2004 distance between patches euclidean. An historical graph comprised 3105 natural lakes connected in one of 18 components, whereas a total of 3944 water bodies lakes and reservoirs were connected in one of separate components in a graph of the contemporary system.
Graph theory urban and keitt 2000 give a general description of ecological applications of graph theory and readers should refer to any number of excellent texts on graphs as a primer e. Landscape connectivity and graph theory semantic scholar. In this context, graph structures have been shown to be a powerful and effective way of both representing the landscape pattern as a. Circuit theory and modelbased inference for landscape. In mathematics and computer science, connectivity is one of the basic concepts of graph theory. Landscape ecology is the flagship journal of a wellestablished and rapidly developing interdisciplinary science that focuses explicitly on the ecological understanding of spatial. The graph is simply a means of summarizing the spatial relationships between landscape elements in a concise way. Graph theory is a well established mainstay of information technology and is concerned with highly efficient network flow. However, uncertainties persist due to the difficulty and expense of gathering empirical data to drive or to validate connectivity models, especially in urban areas, where relationships are multifaceted and the habitat matrix cannot be considered to be binary. Modeling population connectivity by ocean currents, a graph. Among directed graphs, the oriented graphs are the ones that. Among directed graphs, the oriented graphs are the ones that have no 2cycles that. Connectivity is fundamental to understanding how landscape form influences ecological function.
Connectivity defines whether a graph is connected or disconnected. Connectivity of habitat patches is thought to be important for movement of genes, individuals, populations, and species over multiple temporal and spatial scales. The landscape is seen as a raster grid where connectivity between adjacent grid cells is a function of local landscape characteristics, and is computed using circuit theory. Landscape connectivity is fundamental to linking ecological function to landscape form. Illustration of the use of circuits to model spatial connectivity. Modelling in the context of an environmental mobilisation. The use of graph theory has been widely used in landscape ecology to. Of course, as before, the exercises emphasize easytouse, widely available software. The connectivity terms above have a special meaning in graph theory that does not correspond 4 0.
Graph theory metrics quantify, for example, the total length and configuration of edges required to connect all nodes in a graph or the number of edges passing through a given node indicating. Graph theory as an invasive species management tool. Integrating landscape connectivity and habitat suitability. Role of graph theory to facilitate landscape connectivity. We demonstrate the use of graph theory in a metapopulation context, and suggest that graph theory as applied to conservation biology can provide leverage on applications concerned with landscape connectivity. Keywords functional connectivity graph theory reserve network component patch prioritisation introduction habitat loss and fragmentation pose two primary threats to biodiversity across spatial scales that range from the global to very local ones. A graphtheory framework for evaluating landscape connectivity and conservation planning. Connectivity, conservation priorities, corridors, graph theory, habitat fragmentation, habitat loss, landscape metrics, landscape planning, patches, spatial indices abstract the loss of connectivity of natural areas is a major threat for wildlife dispersal and survival and for the conservation of biodiversity in general. We use focalspecies analysis to apply a graphtheoretic approach to landscape connectivity in the coastal plain of north carolina.
Graph theory has been developed as a way of quantifying connectivity among discrete habitat patches minor and urban 2008 but has been. These approaches are unified in their use of graph theory to represent connectivity of landscape. Consequently, several studies apply graph theory to landscape connectivity networks to represent and analyze the connection between landscape spatial structure and species dispersal bunn, urban. In doing so we demonstrate the utility of a mathematical graph as an ecological construct with respect to. Reinhard diestel graph theory electronic edition 2000 c springerverlag new york 1997, 2000 this is an electronic version of the second 2000 edition of the above springer book, from their series graduate texts in mathematics, vol. In doing so we demonstrate the utility of a mathematical. We present an overview of basic elements of graph theory as it might be applied to issues of connectivity in heterogeneous landscapes, focusing especially. In particular, a network graphbased representation of the landscape is being recently but increasingly applied to analyze landscape connectivity e. Characterizing connectivity relationships in freshwaters.
Jun 28, 2017 connectivity is fundamental to understanding how landscape form influences ecological function. Pdf a graphtheory framework for evaluating landscape. Improving landscape connectivity for the yunnan snubnosed. Learning landscape ecology a practical guide to concepts. Chapter 5 connectivity in graphs university of crete. A directed graph is called an oriented graph if none of its pairs of vertices is linked by two symmetric edges. Graph theory is well developed in other fields, including geography transportation networks, routing applications, siting problems and computer science circuitry and network.
Different ecological applications of graph theory focusing especially on connectivity analysis of heterogeneous landscapes for conservation have been recently. Comparison and development of new graphbased landscape. A graph theory framework for evaluating landscape connectivity and conservation planning. Dwc is an important metric capturing the connectivity and density of animals over the landscape. We use focalspecies analysis to apply a graph theoretic approach to landscape connectivity in the coastal plain of north carolina. Meredith rainey bio515 fall 2009 montana state university. Network analysis to assess landscape connectivity trends. It includes new advances in quantifying landscape structure and connectivity such as graph theory, as well as labs that incorporate the latest scientific understanding of ecosystem services, resilience, socialecological landscapes, and even seascapes. Graph theory provides a simple solution for unifying and evaluating multiple aspects of habitat connectivity, can be applied at the patch and landscape levels, and can quantify either. Chapter 5 connectivity in graphs introduction this chapter references to graph connectivity and the algorithms used to distinguish that connectivity.
Modeling population connectivity by ocean currents, a. It has subtopics based on edge and vertex, known as edge connectivity and vertex connectivity. An undirected graph is connected iff for every pair of vertices, there is a path containing them a directed graph is strongly connected iff it satisfies the above condition for all ordered pairs of vertices for every u, v, there are paths from u to v and v to u a directed graph is weakly connected iff replacing all. Ecologists use a variety of terms to connote connectivity. A most distinct use of graph theory is to produce raster model of landscape where connectivity is examined at the scale of a single raster cell 16. By representing the habitat mosaic as a mathematical graph, we show that percolation theory can be used to quantify connectivity at multiple scales from empirical landscape data. Wenwen li, celine clauzel, yunchuan dai, gongsheng wu, patrick giraudoux, et al improving landscape connectivity for the yunnan snubnosed monkey through cropland reforestation using graph theory.
Keywords functional connectivity graph theory reserve network component patch. Labeling of harary graphs is an easy scientific approach towards landscape connectivity. We used graph theory to characterize multiple aspects of landscape connectivity in a habitat network in the north carolina piedmont u. Dynamic optimization of landscape connectivity embedding. The loss of connectivity of natural areas is a major threat for wildlife dispersal and survival and for the conservation of biodiversity in general. This article is an open access publication abstract context connectivity is fundamental to. Whether it is possible to traverse a graph from one vertex to another is determined by how a graph is connected. Using spatial demographic network models to optimize. We developed the framework with a spatial graph based on recreational boater movement and habitat suitability models. Using spatial demographic network models to optimize habitat. However, uncertainties persist due to the difficulty and expense of.
632 794 1113 252 1165 999 215 190 693 678 478 496 1482 780 856 515 704 1119 525 142 1604 166 483 177 1080 85 981 655 546 1107 453 865 535 617