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Connectivity and reserve design: incorporating landscape and population connectivity into conservation planning for changing landscapes and seascapesorganized by Carlos Carroll (Wilburforce Foundation), Reed Noss (University of Central Florida), and Gary Tabor (Wilburforce Foundation)THE BEST LAID PLANS OF BEASTS AND MEN: ECOLOGICAL CONNECTIVITY IN CONSERVATION PLANNING REQUIRES CONNECTIVITY AMONGST CONSERVATION PLANS GARY TABOR, Carlos Carroll, and Joel Clement, Wilburforce Foundation, USA, gary@wilburforce.org The best laid plans are only as good as their implementation, but the radiation of conservation planning is practically overwhelming implementers. Among their challenges: (a) many conservation plans are deployed within a single organizational purview, yet conservation action on the ground is implemented by a range of entities from non-profit groups to government agencies; (b) as large-scale conservation efforts advance around the world, implementers are beset with a diversity of plans with varying goals, values and assumptions; (c) the underlying science for these plans is often confusing, inconsistent, or derived from widely divergent methods and objectives; and (d) the reality of conservation on the ground changes so rapidly that plans may be outdated upon completion, forcing adaptation on the fly and compromising evaluation efforts. This presentation looks at conservation planning from the “demand” side—the uptake of planning products by an implementer. The Yellowstone to Yukon region is one of the world’s largest landscape conservation efforts, with over 150 NGOs, government agencies, universities, and community groups implementing conservation on the ground. Most share a vision for preventing habitat fragmentation in some of the wildest regions of North America. Can consilience be achieved in conservation planning at this large scale? PLANNING FOR BIODIVERSITY PROCESSES IN THE CONTEXT OF ANTHROPOGENIC LANDSCAPE DYNAMICS: HISTORY AND RECENT DEVELOPMENTS BOB PRESSEY, The Ecology Centre, University of Queensland, St. Lucia, QLD, Australia, r.pressey@uq.edu.au Systematic conservation planning involves explicit goals and decisions about conservation management. Since the early 1980s, the field has developed mainly in terrestrial environments but increasingly also in marine systems. Freshwater applications are still unusual and present particular, though not insurmountable, problems. Early systematic methods dealt mainly with biodiversity pattern (e.g., maps of species localities and vegetation types) and assumed implicitly that anthropogenic landscape dynamics would not interfere with implementation. Recent developments have taken two new directions. First, planners are considering temporal choices, or scheduling, as well as spatial choices. This acknowledges that implementation of conservation action is usually incremental and accompanied by progressive attrition of biodiversity values. Second, systematic methods are being developed to deal with biodiversity processes through connectivity and other design considerations. Although these directions need much further exploration, there has been some important progress in both. A third, vital direction for planners is to combine the previous two—to plan for the dual dynamics of biodiversity processes in the context of anthropogenic landscape change. Few planners have set foot in this area, which nonetheless represents the major challenges and opportunities in nature conservation. OVERVIEW OF NEW MATHEMATICAL METHODS FOR INCORPORATING CONNECTIVITY INTO RESERVE DESIGN JUSTIN WILLIAMS, Department of Geography, Johns Hopkins University, Baltimore, MD, USA, jcwjr@jhu.edu Inter-site connectivity has been incorporated into recent mathematical optimization models for nature reserve site selection to promote migration, dispersal, and recolonization. Connectivity may be defined and measured in different ways, and whether a particular measure is appropriate depends on the conservation goals for the reserve system. In this talk, methods for optimizing inter-site connectivity within decision models are briefly reviewed. This may mean requiring a specified level of connectivity to be achieved, or maximizing the level of connectivity achieved subject to other constraints. The formulation of objectives and constraints, and their implications for reserve design outcomes, are explored. Issues include single species vs. multiple species, site adjacency and proximity, and threshold distances. Exact (integer programming) and heuristic approaches are discussed. MATHEMATICAL METHODS FOR SELECTING CONTIGUOUS RESERVE NETWORKS Diogo Alagador, J. ORESTES CERDEIRA, Kevin Gaston, and Leonor Pinto, Intituto Superior de Agronomia, Univ. Tecnica de Lisboa, Lisboa, Portugal (DA, JOC, LP), Biodiversity and Macroecology Group, University of Sheffield, United Kingdom (KG), orestes@isa.utl.pt An important issue in the design of protected areas for conservation is to identify networks capturing the regional species assemblage, where some level of adjacency or connectivity between areas is achieved. We describe three different models to incorporate connectivity in the design of reserve networks. The first is a full connectivity model in which totally contiguous reserves of minimum size where all species are represented are obtained. The second model deals with the presence of mandatory sites (hotspots), which are quite often located far apart. Instead of forcing strict contiguity, which will probably lead to long and thin reserve networks of unclear ecological significance, we let the hotspots act like attractive nuclei and promote the aggregation of sites around them. The third model considers that different species may have different dispersal abilities, with each species having its own levels of adjacency, and treats connectivity on a species by species basis. Computational results with real data and data generated using neutral models are reported. COMPARING RESERVE DESIGN APPROACHES THAT ACCOUNT FOR CONNECTIVITY MAR CABEZA and Atte Moilanen, Department of Biological and Environmental Sciences, University of Helsinki, Finland, cabeza@cc.helsinki.fi The idea that landscape structure influences species distribution patterns and persistence is central to metapopulation biology, landscape ecology, and spatial ecology in general. Spatial population dynamics also affects optimal reserve design, as the spatial distribution of reserves and the distribution of habitat around them influence species persistence in those reserves. Conservation planning research has turned its attention to spatial issues, with the development of methods aimed at creating well connected reserve networks. In principle, by integrating (meta)population viability analysis-type models into reserve selection procedures, it is possible to select sets of sites of an optimal spatial configuration so that persistence of the species is guaranteed. However, in practice, modelling the spatial effects for many species simultaneously is not trivial. This is because of the high data requirements and great computational complexity. Nonetheless, there are several ways to approach these problems. Different alternatives will be compared, including methods that range from those that are less to those that are more biologically realistic in the way connectivity effects are considered, while at the same time moving from less computationally demanding tools to methods that are harder to parameterize and more computationally complex. DISSECTING HABITAT CONNECTIVITY Nathan Schumaker, Madhura Niphadkar, and CARLOS CARROLL, U.S. Environmental Protection Agency, Corvallis, OR, USA (NS), San Diego State University, CA, USA (MN), Klamath Center for Conservation Research, Orleans, CA (CC), carlos@klamathconservation.org Connectivity is increasingly recognized as an important element of a successful reserve design. Connectivity matters in reserve design to the extent that it promotes or hinders the viability of target populations. While conceptually straightforward, connectivity is difficult to quantify. And because it is only one of many determinants of population viability, the consequences for wildlife of altering connectivity are hard to predict. We describe our application of a simulation model that links individual movements and occupancy rates to local and regional population dynamics. We then illustrate how connectivity indirectly alters population viability by controlling occupancy rates across a landscape, and by helping to determine the characteristics of the occupants. This study adds to our understanding of the mechanisms through which connectivity influences the success or failure of conservation efforts. MULTISPECIES ISSUES IN THE DESIGN OF MARINE RESERVE NETWORKS STEVE GAINES, Brian Gaylord, Brian Kinlan, and Sarah Lester, University of California, Santa Barbara, CA, USA (SG, BK, SL), University of California, Davis, CA, USA (BG), gaines@msi.ucsb.edu Marine reserves are islands of protection in a sea of nets, hooks, and trawls. They are being established to enhance both conservation and fisheries sustainability. Their success depends on the movement of adults and young. Because reserves only protect adults within the reserve, species with large adult movement receive little benefit. The movement of young, however, affects reserve effectiveness in a very different way. The scales of larval dispersal can be large and vary enormously among species. Because larvae are typically not at risk while dispersing, they provide a critical source of connectivity between distinct reserves and they provide a source of recruitment for fished populations outside reserve boundaries. Given that larval dispersal varies by many orders of magnitude among species, how can reserves work for a broad diversity of species? Are there inherent compromises in reserve design? Models of reserve networks can address these questions and explore the impact of marine reserves on species with different life histories and dispersal kernels. Emerging models suggest there are clear compromises associated with when density dependence occurs in the life cycle and how far larvae disperse. However, for a broad range of relevant life histories and characteristic dispersal distances, there are network designs that provide simultaneous benefit to population persistence and fisheries yields. These common solutions inevitably include large numbers of moderate sized reserves. INCORPORATING CONNECTIVITY INTO THE DESIGN OF MARINE RESERVES ALAN HASTINGS, Department of Environmental Science and Policy, University of California, Davis, CA, USA, amhastings@ucdavis.edu Models for understanding the role of habitat availability and resource use in the design of marine protected areas necessarily rely upon the central issue of connectivity. The role played by both simple analytic models and more complex simulation models will be discussed, and then the role played by simple analytic models will be emphasized. Ways of incorporating data from physical sources and from analyses of habitat quality will first be presented in the context of single species models, beginning with the fundamental question of deducing requirements for persistence in the simplest setting. Next, consequences of habitat and temporal variability will be included to answer the question of the importance of network effects in the design of marine protected areas. Here, the closure of the system, loops connecting a patch back to itself, are central to designing networks of reserves where the species are persistent. The ways in which the models highlight the data requirements that would be necessary to design reserves, and how to design reserves in the face of limited data, will be emphasized. Additionally, limitations of current models and future directions for modeling that will aid in the design of marine protected areas will be considered. CONNECTING THE DOTS MEANS MORE THAN LINES: CONNECTIVITY ISSUES AND APPROACHES FOR REGIONAL FRESHWATER SPECIES CONSERVATION JONATHAN HIGGINS, The Nature Conservancy, Chicago, IL, USA, jhiggins@tnc.org Regional connectivity is necessary for many species to access habitats for different life history stages, for linkages to support metapopulation dynamics, and for many physical processes to adequately function. Even if spatial connectivity seems to exist from maps, processes such as natural flow are generally required for functional and temporal connectivity. For example, natural flow regimes are necessary for seasonal connectivity to floodplain habitats and to facilitate the movement of species during different life stages. Connectivity is altered in most regional aquatic landscapes from a variety of barriers including dams, levees, culverts, poor habitat conditions, and unnatural flow regimes. Most regional conservation assessments have focused on identifying areas with biodiversity that are necessary to conserve, but need to better address different aspects of connectivity at multiple scales and support the development and implementation of strategies to maintain and restore connectivity. Examples of regional freshwater conservation assessments from the northeastern United States and the upper Mississippi River basin will be used to illustrate strengths and limitations in existing information and products, an array of challenges and strategies to achieve regional connectivity in altered landscapes, and important next steps to address regional connectivity for freshwater biodiversity conservation. CONNECTIVITY DESIGN FOR ISLAND SYSTEMS STEVE SCHILL, The Nature Conservancy, Richmond, UT, USA, sschill@tnc.org The Nature Conservancy (TNC) has recently completed a two year conservation assessment of the Greater Caribbean Basin. An integral part of this analysis was an assessment of the spatial relationship between occurrences, which plays a role in maintaining natural dynamics. Tools were developed that use grid-based modeling and graph theory to capture a variety of connectivity aspects within the conservation design process. These aspects included quantification of existing connectivity, assessing degree of isolation, and evaluating the importance of habitat patch based on varying dispersal distances. Least-cost-path (LCP) distances were modeled between habitat patches based on a mobility cost surface designed by expert opinion of how animals respond to different land cover types and the degree of difficulty for crossing various environments. Potential corridors between habitat patches were identified based on density thresholds of LCPs between each habitat type. Habitat patches were assessed for their degree of isolation based on connection distances within connectivity networks and evaluated how important each patch in the landscape contributes to overall island connectivity. Results of the connectivity and corridor models are being used to investigate and compare the connectivity of alternative protected area networks to see which provides better connectivity between habitat patches. OPTIMIZING CONNECTIVITY UNDER CLIMATE CHANGE: USING NETWORK FLOW TO DESIGN DISPERSAL CORRIDORS FOR THE CAPE PROTEACEAE STEVEN PHILLIPS, Paul Williams, Guy Midgley, and Aaron Archer, AT&T, Florham Park, NJ, USA (SP), Biogeography and Conservation Laboratory, The Natural History Museum, London, UK (PW), Kirstenbosch Research Centre, National Botanical Institute, Cape Town, South Africa (GM), AT&T Labs–Research, Florham Park, NJ, USA (AA), phillips@research.att.com Williams et al. (2005) introduced a novel framework for planning protected areas to allow the Cape Proteaceae to shift in response to climate change, incorporating both a minimum range size and species limited dispersal abilities. Each species should have at least 35 grid cells (approximately 100 square km) with predicted suitable conditions in protected areas at all times between 2000 and 2050. The goal is to design multiple corridors of connectivity for each species, minimizing the total number of cells requiring protection. We show that both minimum range size and limited dispersal abilities can be naturally modelled using the concept of network flow. This allows us to apply well-established tools for solving network flow problems. We reduce the number of currently unprotected cells requiring protection by a third, from 1602 to 1068, while still achieving the same planning goals. We show that this is the best possible: the given planning goals cannot be achieved with fewer cells. Further, our method allows for flexibility and refinement of the underlying climate-change, species habitat-suitability and dispersal models. In particular, we propose an new formalization of a minimum range size moving through time, and use network flow to achieve the revised goals with 995 cells, showing that a minimum of 992 cells is required. We discuss extensions for modelling continuous habitat suitability and trading off dispersal requirements against the number of protected cells. SELECTING CORRIDORS THAT INSURE PERSISTENCE OF WIDE-RANGING SPECIES AND ECOLOGICAL PROCESSES: EXAMPLES FROM SOUTH AFRICA MATHIEU ROUGET, Richard Cowling, Amanda Lombard, and Andrew Knight, South African National Biodiversity Institute, Pretoria, South Africa (MR), Nelson Mandela Metropolitan University, Port Elizabeth, South Africa (RC, AL, AK), rouget@sanbi.org A major challenge for conservation assessments is to identify priority areas that incorporate biological patterns and processes. Because large-scale processes are mostly oriented along environmental gradients, we propose to accommodate them by designing regional-scale corridors to capture these gradients. Based on systematic conservation planning principles, such as representation and persistence, we identified large tracts of untransformed land (i.e., conservation corridors) for conservation that would achieve biodiversity targets for pattern and process and capture key environmental gradients. Here we report on various approaches used to identify regional-scale corridors within South Africa biodiversity hotspots and discuss their relative advantages. We combined methods such as least-cost path analysis, spatial connectivity measures, target-driven algorithms, and expert knowledge to design corridors in real-world conservation planning. Corridors were spatially identified on the basis of biome representation, habitat transformation and degradation, wildlife suitability, irreplaceability of vegetation types, protected area networks, and future land-use pressures. Our corridor design can provide a tool for quantifying trade-offs between various criteria (biodiversity pattern and process, implementation constraints and opportunities). A land-use management model was developed to facilitate implementation of conservation actions within these corridors. BUILDING CONNECTED NETWORKS IN A RAPIDLY DEVELOPING HUMAN LANDSCAPE: AN EXAMPLE FROM FLORIDA DAVID BREININGER, Reed Noss, Pedro Quintana-Ascencio, Brean Duncan, and Eric Menges, Dynamac Ecological Programs Kennedy Space Center, FL, USA (DB, BD), Department of Biology, University of Central Florida, Orlando, FL, USA (RN, PQA), Archbold Biological Station, Lake Placid, FL, USA, breindr@cfl.rr.com Florida communities remained largely intact until widespread urbanization began two to five decades ago. Habitat destruction fragmented and isolated remnant populations of many species and, combined with alteration of disturbance regimes, profoundly affected community and ecosystem dynamics. Physically connected networks have been successfully reestablished along many wetland systems but connectivity has been difficult to establish within uplands despite many state and local conservation acquisition programs. We review the consequences of this loss of connectivity among remnant patches of Florida scrub, and suggest approaches to maintain or mitigate the loss of physical connectivity. Defining and maintaining natural fire regimes, essential for sustaining biological diversity, confounds the identification and management of connectivity within upland populations and landscapes. Local extirpation due to disrupted fire regimes has preceded extensive fragmentation. Designing reserves that can accommodate prescribed burning is often recognized in conservation planning. Implementation of conservation plans often focuses on land acquisition and underestimates costs for land management, habitat restoration, monitoring, research, and translocation. Planning usually ignores issues of connectivity. We argue that a research, monitoring, and adaptive management approach needs to be more directly integrated into the conservation planning and funding. We need a greater focus on sustaining viable populations that are demographically and genetically, connected. APPLICATION OF RESERVE DESIGN PRINCIPLES TO REAL LANDSCAPES: LESSONS FROM THE NORTHWEST FOREST PLAN BARRY NOON, Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, CO, USA, brnoon@cnr.colostate.edu In 1994, the Northwest Forest Plan, covering 94 million acres in the Pacific northwest region of the United States, was implemented to address concerns about the overharvest of late-seral forests and the effects of forest management on the long-term viability of the Northern Spotted Owl (Strix occidentalis caurina). Even though the plan evolved with a broad ecosystem perspective, it remained anchored in the Spotted Owl reserve design proposed in 1990. At that time, reserve design principles were based on little more than “rules of thumb.” Based on a criterion of stable or increasing populations, a decade later the results of intensive monitoring of several Spotted Owl populations suggest a continuing range-wide decline even though rates of timber harvest have declined dramatically on federal lands. Is the cause of the continuing decline of spotted owls a consequence of flawed design principles that have been addressed by the scientific community within the intervening 15 years? By contrasting the qualitative rules used in 1990 with current insights from spatial ecology, I will argue that this is not the case. Conservation failures are seldom limited by the limitations of science and our analytical methods but rather by uncertainties that lie outside the realm of science. NETWORK DESIGNS AND POLITICAL REALITIES IN TIGER LANDSCAPES OF ASIA DALE MIQUELLE and Carlos Carroll, Wildlife Conservation Society, Bozeman, MT, USA (DM), Klamath Center for Conservation, Orleans, CA, USA (CC), dalemiq@vlad.ru Models developed for defining connected networks that act to conserve tigers in existing natural landscapes have advanced considerably in the past decade. These advances are partly in response to the urgency of conservation measures in the increasingly fragmented Asian landscape, but may often be simply academic exercises that have little conservation impact. Initial attempts to design conservation landscapes for tigers ranged from Asia-wide attempts to define “tiger conservation units” to simplistic attempts to define connected networks of protected areas based on basic biological principles and political realities within ranges of existing populations. More recently, two approaches to conservation planning—least-cost pathways, and spatially explicit population viability analyses have been used in tiger conservation planning. Differences in assumptions associated with “connectivity” result in important differences in reserve design, but neither provides all the tools for conservation planning. The disconnection between scientific analyses and political interests, both national and transboundary, is the more serious problem hindering effective use of network designs. SUMMARY: WHERE NEXT IN CONNECTIVITY-BASED CONSERVATION PLANNING? REED NOSS, Department of Biology, University of Central Florida, Orlando, FL, USA, rnoss@mail.ucf.edu Functional, as opposed to structural, connectivity is determined by the intersection of an organism’s life history and the structure of the landscape. Although no two species are likely to have identical connectivity requirements, identification of fragmentation-sensitive focal species at several spatial scales and representing multiple habitat types is a promising approach in any given region. I summarize lessons gleaned from other presentations in this symposium, provide additional examples of the use of focal species modeling and field research to determine connectivity requirements, and suggest priorities for future research. Current knowledge often provides a defensible strategy for incorporating connectivity into conservation planning. Nevertheless, increased use of quantitative habitat and population modeling, combined with extensive field verification and expert judgment, will make corridor design more reliable. A useful approach is to use existing knowledge to build models and develop alternative connectivity designs, coupled with field measurements of responses of organisms to various corridors and landscape configurations. One of the greatest challenges is to address, in a practical and cost-effective way, the problem of roads as movement barriers and sources of mortality. | |||||||||||||||||
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