ISSUES IN ECOLOGY NUMBER SIXTEEN FALL 2012 habitat-for example,a highway bisecting may be more releva movement corridor. s;for e such as food,breeding habtat,or refuge from or a heterogeneous assemblage of meadow the land ms to ecological requirements becomes even sidermaoinngPCeicorghoaoiCYoe tate moveme beween patches,are fre. that contribute to andscape connectivity for tion of corridors can maintain connectivity for s or large views the impor Corridors n rovide structural conpectivity rent science-based for mitigating the and are consistent with the functional con- negative ecological effects of fragmentation, at can take dis a ga opportunities for developing policies and man The growing movement toward ecosystem-based management.including ne orks of no-take zones in marine ecosvstems (marine ed areas or MPA sI re uires that these conservation areas be deli and adequately spaced to allow for conn into h functionlly and structurally linked to each other by both biological (e.g. dispersal of organisms)and physical (e.g..currents ld become genetically isolated if populations cannot reach each othe dermining the viability of populations in the MPA should include MPAs and other conservation and managen ent ar reas that support each other by taking advantage of oceanic currents ween the a is a critic rvation areas that are d d critical to marine ation ectives,whic cover 26%of the ecoregion en put are used to track species'dispersal from site to site as well as movement through the matrix(for example satellite trac g and the For example.sea turtle and whale shark tagging programs are already underway in the ecoregion,and ity in marine spatia The Ecological Society of America.esahg@esa.ord esa 3© The Ecological Society of America • esahq@esa.org esa 3 ISSUES IN ECOLOGY NUMBER SIXTEEN FALL 2012 habitat – for example, a highway bisecting a movement corridor. For any given species, some parts of the landscape provide better opportunities than others to fulfill its ecological requirements, such as food, breeding habitat, or refuge from predation. Fragmentation and degradation can further increase the patchiness of the land￾scape in terms of meeting a species’ needs. Conserving connectivity in this context requires identifying, maintaining, and possibly enhancing the linkages between suitable patches of habitat in the landscape. Corridors, which are generally linear spaces that facili￾tate movement between patches, are fre￾quently used as a tool for conserving or enhancing linkages. The creation or protec￾tion of corridors can maintain connectivity for mobile species, such as ungulates or large felines that typically have large territories. Corridors provide structural connectivity and are consistent with the functional con￾nectivity needs of animals that can take advantage of linear spaces to move among dis￾parate habitat patches. However, landscape connectivity is highly diverse and species￾dependent, and other forms of connectivity may be more relevant to other types of organ￾isms; for example, a linked mosaic of small wetlands for breeding populations of amphib￾ians, continuity of vegetated intertidal rocky substrate along a coastline for a marine snail, or a heterogeneous assemblage of meadow plant communities with different flowering times for a population of pollinators. The challenge of matching connectivity patterns to ecological requirements becomes even greater when we expand our thinking to con￾sider maintaining or restoring connectivity for multiple species or entire communities. Many populations and ecosystem functions are dependent on extensive, well-connected habitats; however, understanding the factors that contribute to landscape connectivity for specific populations, species, or communities is challenging. This Issue reviews the impor￾tance of habitat connectivity, summarizes cur￾rent science-based strategies for mitigating the negative ecological effects of fragmentation, explores data gaps and limitations of connec￾tivity models, and describes obstacles and opportunities for developing policies and man￾agement approaches that improve connectiv￾ity and reach conservation goals. Case Study 1. Managing for Marine Connectivity: Marine Protected Areas in the Gulf of California, Mexico The growing movement toward ecosystem-based management, including networks of no-take zones in marine ecosystems (marine protected areas, or MPAs) requires that these conservation areas be deliberately and adequately spaced to allow for connectivity. The performance of a network of sites designed with the two-fold purpose of protecting commercial species and allowing for spillover effects (movement of organisms from protected areas into harvestable areas) will largely depend on whether sites in a network are functionally and structurally linked to each other by both biological (e.g., dispersal of organisms) and physical (e.g., currents) processes. Although the number and extent of MPAs has increased recently, studies have shown that, on a global scale, average dis￾tance between neighboring MPAs exceeds the distance of reef organism propagule dispersal. This distance suggests that some taxa could become genetically isolated if populations cannot reach each other, undermining the viability of populations in the MPAs. The conservation of species, habitats, and ecoregions depends on developing practical, efficient, and effective planning strategies. This is especially true in the marine realm, where threats are diffuse and difficult to both identify and quantify. Well-designed networks should include MPAs and other conservation and management areas that support each other by taking advantage of oceanic currents and movement/migration capabilities of species. They also provide much-needed resilience against a range of threats. Because estab￾lishment of isolated marine reserves may not alone suffice for the conservation of biodiversity, identifying the level of connectivity between the areas is a critical aspect in network design. In the Gulf of California, Mexico (GOC), two organizations, Comunidad y Biodiversidad and The Nature Conservancy, recently com￾pleted a marine ecoregional assessment to identify priority conservation sites and establish a network of conservation areas. This analysis identified 54 conservation areas that are deemed critical to marine conservation objectives, which cover 26% of the ecoregion. An important step towards implementing the assessment will be to account for connectivity between putative sites. To move from con￾nectivity assessments based exclusively on structural attributes of connectivity to a detailed assessment of actual connectivity, mod￾els are used to track species’ dispersal from site to site as well as movement through the matrix (for example, satellite tracking and the development of oceanographic models for the entire ecoregion). Pop-up satellite archival tags are being used globally for many marine species (e.g., the Tagging of Pacific Predators Program, http://www.topp.org/) and can greatly enhance knowledge of the dispersal of focal species. For example, sea turtle, cetacean, and whale shark tagging programs are already underway in the ecoregion, and expanded versions of these programs are expected to provide a more complete understanding of connectivity throughout the ecore￾gion. Integrating data from these tagging programs into the GOC ecoregional assessment is an important priority in understanding the role of connectivity in marine spatial planning