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1.
Helen J. Edwards 《Biological conservation》2010,143(2):457-470
Computational methods for marine reserve design are frequently used as decision-support tools for the identification of conservation areas. Most reserve-selection algorithms minimise the cost of the reserve system whilst aiming to meet specified biodiversity objectives. Here, we extend a widely-used selection algorithm, Marxan, to incorporate several important considerations related to biodiversity processes and management. First we relax the scorched earth assumption to allow conservation features in non-reserve zones to contribute explicitly to conservation objectives. To achieve this, we generate conservation targets at landscape scales rather than focusing purely on the representation of features within reserves. Second, we develop the notion of spatial dependencies further to incorporate spatial heterogeneity in the value of individual conservation features such as habitat types. We use the example of ontogenetic migrations of fish from mangroves to coral reefs because it nicely demonstrates how spatial ecological processes generate predictable heterogeneity in habitat value that should be considered in the reserve design process. Lastly, we show how habitat value can be disaggregated into ecosystem processes and services. Using a case study for the Belize Barrier Reef we compare reserve networks generated using our new approach with the results of traditional analyses. Consideration of the contribution of different protection zones, connectivity among habitats and more complex management goals resulted in up to a 52% increase in the mean biomass of commercially and ecologically-important fish species represented in the landscape. Our approach strengthens the ecological basis of reserve-design algorithms and might facilitate the uptake of ecosystem-based management into reserve design. 相似文献
2.
The primary goals of marine reserves include protecting biodiversity and ecosystem structure. Therefore, a multispecies approach to designing and monitoring reserve networks is necessary. To gain insight into how the interactions between species in marine communities may affect reserve design, we synthesize marine reserve community models and community models with habitat destruction and fragmentation, and we develop new extensions of existing models. This synthesis highlights the potential for species interactions to alter reserve design criteria; in particular, accounting for species interactions often leads to an increase in reserve size necessary to protect populations. Accounting for species interactions also indicates the need to base reserve design and monitoring on a variety of species, especially long-distance dispersers, inferior colonizers, and specialists. Finally, the new model extensions highlight how, given dispersal, source populations outside reserves as well as increases in fished populations after reserve establishment may negatively affect reserve populations of competitors or prey. Therefore, multispecies harvest dynamics outside reserves and before reserve establishment are critical to determining the appropriate reserve size, spacing, and expectations after establishment. These models highlight the importance of species interactions to reserve design and provide guidelines for how this complexity can begin to be incorporated into conservation planning. 相似文献
3.
Many commercially important fish species use coastal marine environments such as mangroves, tidal flats and seagrass beds as nurseries or breeding grounds. The ecological importance of spatially connected habitats to conservation is well established for terrestrial environments. However, few studies have applied spatial metrics, including measures of structural connectivity to marine environments. We examined the relationship between catch-per-unit-effort for commercially caught species and the spatial patterning of mapped benthic habitat types along the coast of Queensland, Australia in their dominant fisheries (trawl, line, net or pot fisheries). We quantified the composition and spatial configuration of seascapes and calculated coastline length, number of estuaries, river length and geographical latitude using 12 metrics within ninety 30-nautical-mile grid cells, which supported inshore fish catch data from 21 species groups. Multiple regression analysis and non-metric multidimensional scaling plots indicated that ecological linkages may exist between geomorphic coastal features and nearshore fisheries production for a number of species groups. Connectivity indices for mangroves, salt marsh and channels explained the largest proportion (30–70%), suggesting the importance of connected tidal wetlands for fisheries. Barramundi (Lates calcarifer) catch-per-unit-effort was best explained by the number of wetland patches, mangrove connectivity and wetland connectivity (r2 = 0.38, n = 28). Catch-per-unit-effort for the Gulf of Carpentaria was highly correlated with wetland connectivity, the number of estuaries and seagrass patch density (r = 0.57, n = 29). The findings could guide the spatial design of marine protected area networks to maintain ecosystem services and avoid potential disruption to connectivity caused by habitat removal or modification. Application of the same approach to analyses of finer spatial scales would enable catch information to be related to particular estuarine habitats and provide better understanding of the importance of habitat connectivity for fisheries. 相似文献
4.
Marine reserves are increasingly advocated not only as conservation but also as fisheries management tools to safeguard the decline of coastal fishing resources. Still, conclusive evidence of their functioning is lacking, amongst others due to the influence of spatio-temporal variations in fish populations and habitat heterogeneity which could hamper a sound data interpretation. We conducted a spatial analysis of the benefits of the Medes Island Marine Reserve by combining geostatistical and Geographic Information System (GIS) tools. Concurrently, we analysed effects of trends reflecting habitat heterogeneity and spatial structuring of data on spatial predictions of fish catch per unit effort (CPUE) and length. Predicted spatial patterns showed the complexity and simultaneous action of trend factors leading to mostly non-linear gradients in CPUE and length data. CPUE of total fish and CPUE and length of common pandora (Pagellus erythrinus) increased close to the Integral Reserve due to direct and indirect reserve effects. CPUE and length of striped red mullet (Mullus surmuletus) slightly increased also near the Integral Reserve, but distinct reserve effects could not be identified due to the strong influence of artificial reefs. We conclude that the spatial dimension of the Buffer Zone, where artisanal fisheries are allowed, permits in general protection only for target species, favouring a habitat with no discontinuities from the reserve outwards. Our spatial approach to assess reserve benefits provides major insights into complex systems like coastal marine reserves in the northwestern Mediterranean. In addition, it contributes to a crucial aspect of marine conservation, viz. the decision on the spatial dimension of protected areas. 相似文献
5.
Like most ecosystems of the world, tropical dry forests of the central coast of the Gulf of Mexico are inadequately preserved. Given that reserve expansion is unlikely, it is imperative that the conservation capacity of the matrix surrounding reserves is enhanced. Here, we examine the habitat value of isolated pasture trees and patches of secondary regrowth in terms of their terrestrial and arboreal ant assemblages in both a wet and dry season. These simplified wooded systems increase species densities within the agricultural matrix and provide habitat for some forest ant species. Estimated species richness of arboreal ants was particularly low on isolated trees, highlighting an important limitation. This was not the case for terrestrial ants, which were particularly species rich under isolated trees. We also found that the inter-site variations in species densities and similarity to the forest ant assemblage for terrestrial and arboreal strata were not correlated, suggesting that responses to restoration may not be as uniform as often thought. This has important implications for the use of indicator taxa in suggesting the response of other taxa. In terms of species composition, neither secondary regrowth nor isolated trees were appropriate replacements for forest fragments, even though the studied forest fragments were small (13-32 ha). The ant assemblages did not exhibit a seasonal change in composition. However, season influenced the contrast between habitats, with isolated trees being more distinct from pasture, and regrowth more closely resembling forests, during the wet season. Microclimatic variables indicate that the forests were least affected by the tropical dry season, and this may contribute to their characteristic fauna. We conclude that even small forest patches make a unique contribution to landscape conservation and that, where reserves are limited, conscientious management of the landscape matrix may provide some species with sufficient new habitat to survive outside of reserve systems. These conclusions are influenced by both season and strata studied. 相似文献
6.
No-take reserves constitute one tool to improve conservation of marine ecosystems, yet criteria for their placement, size, and arrangement remain uncertain. Representation of biodiversity is necessary in reserve planning, but will ultimately fail for conservation unless factors affecting species’ persistence are also incorporated. This study presents an empirical example of the divergent relationships among multiple metrics used to quantify a site’s conservation value, including those that address representation (habitat type, species richness, species diversity), and others that address ecological processes and viability (density and reproductive capacity of a keystone species, in this case, the black chiton, Katharina tunicata). We characterized 10 rocky intertidal sites across two habitats in Barkley Sound, British Columbia, Canada, according to these site metrics. High-richness and high-production sites for K. tunicata were present in both habitat types, but high richness and high-production sites did not overlap. Across sites, species richness ranged from 29 to 46, and adult K. tunicata varied from 6 to 22 individuals m−2. Adult density was negatively correlated with species richness, a pattern that likely occurs due to post-recruitment growth and survival because no correlation was evident with non-reproductive juveniles. Sites with high adult density also contributed disproportionately greater potential reproductive output (PRO), defined by total gonad mass. PRO varied by a factor of five across sites and was also negatively correlated with species richness. Compromise or relative weighting would be necessary to select valuable sites for conservation because of inherent contradictions among some reserve selection criteria. We suspect that this inconsistency among site metrics will occur more generally in other ecosystems and emphasize the importance of population viability of strongly interacting species. 相似文献
7.
The Eurasian black vulture (Aegypius monachus) is a globally endangered species, vulnerable in Europe and endangered in Greece. We modelled its nesting preferences in Dadia reserve, northeastern Greece using logistic models at multi-scale level combined by Bayesian statistics. Compared with the random sites, the vultures nested at trees with greater diameter (DBH), lower height, and lower total number of trees around the nest tree, steeper slopes and greater distance from forest roads. Our results indicate that conservation and management guidelines for black vultures must aim: (1) to preserve old, isolated mature trees in the reserve, (2) to maintain the zones of strict protection as vulture sanctuary, including most of the suitable nesting habitat, (3) to protect the apparently suitable but still unused habitat in the rest of the reserve from disturbance and logging, (4) to monitor any changes in habitats and use our models to evaluate and predict their effect on vulture nesting in the reserve. 相似文献
8.
Reserves are frequently constrained in design and size by various financial, social or political factors. Maintenance of existing reserves must therefore rely on strategic management practices, and prioritization of conservation activities within them. Identification of global and regional hotspots have been effective for prioritizing conservation activities. Yet, identification of micro-hotspots, or overlapping areas of endemic and rare species that are under threat at the landscape scale, have largely been ignored. From a reserve management point of view, knowledge of critical micro-hotspots within a reserve, are focal points for directing cost effective, conservation initiatives, especially removal of invasive alien plants which are a major threat to biodiversity.Using diversity patterns of dragonfly assemblages, many endemic and threatened, within a biosphere reserve located in the core of a global biodiversity hotspot, we investigated the concept of micro-hotspots. As biosphere reserves contain zones with varying degrees of anthropogenic impact, we also investigated the value of buffer and transition zones for complementing the dragonfly fauna of the reserve core. We found a distinct micro-hotspot within the protected core zone which shows concordance for both endemism and species richness. We conclude that focused conservation actions to remove invasive alien plants within this micro-hotspot would help insure its continued integrity. Furthermore, while there is greater habitat degradation within the buffer and transition zones, they support many additional species, but not those necessarily endemic or threatened. The complementary value of buffer and transition zones therefore lies in increasing habitat heterogeneity and species richness of the whole reserve. 相似文献
9.
Marine protected areas export larvae of infauna, but not of bioengineering mussels to adjacent areas
Populations of organisms that create habitat can often be fragmented throughout landscapes by anthropogenic disturbances such as harvesting and loss or change to the identity of such bioengineers may lead to large changes in biodiversity. Using the fauna associated with a bioengineer, the intertidal mussel Perna perna, we tested hypotheses about the relative importance of larval export from protected populations in marine reserves. Harvesting led to the replacement of P. perna and the domination of shores outside reserves by turf-forming coralline algae, mostly Corallina spp. We determined whether the diverse fauna recruiting onto artificial units of habitat placed within mussel beds differed between reserves and non-reserve areas or whether shores outside reserves, and open to harvesting, received recruits through larval export from reserves. Furthermore, we determined whether this was affected by the distance away from reserves and whether colonisation was achieved by movement of adults from surrounding biogenic habitats or via the plankton. Overall, we found no effect of increasing distance away from a reserve on the cover of adult mussels or associated fauna. We found strong effects of the presence of marine reserves on abundances of molluscs and polychaetes but not crustaceans. There were greater densities of molluscs in sites with a reserve (i.e. inside reserves, and up to 5 km outside reserve boundaries), but more polychaetes in exploited sites. For molluscs, this pattern was driven by gastropods rather than bivalves. Furthermore, although reserves had greater cover of adult mussels than non-reserve areas, recruitment of mussels was not greater inside or near to reserves. Our study illustrates the effectiveness of these reserves in protecting stocks of adult mussels, and although there was no evidence that reserves provided export of the larvae of mussels (the target species), they did provide larval export of non-targeted associated species. By protecting a harvested bioengineer and through export of the larvae of its associated fauna, these reserves fulfil some, but not all the conservation aims of a marine protected area. 相似文献
10.
Jared M. Diamond 《Biological conservation》1975,7(2):129-146
A system of natural reserves, each surrounded by altered habitat, resembles a system of islands from the point of view of species restricted to natural habitats. Recent advances in island biogeography may provide a detailed basis for understanding what to expect of such a system of reserves. The main conclusions are as follows:The number of species that a reserve can hold at equilibrium is a function of its area and its isolation. Larger reserves, and reserves located close to other reserves, can hold more species.If most of the area of a habitat is destroyed, and a fraction of the area is saved as a reserve, the reserve will initially contain more species than it can hold at equilibrium. The excess will gradually go extinct. The smaller the reserve, the higher will be the extinction rates. Estimates of these extinction rates for bird and mammal species have recently become available in a few cases.Different species require different minimum areas to have a reasonable chance of survival.Some geometric design principles are suggested in order to optimise the function of reserves in saving species. 相似文献
11.
Although much research has been undertaken to design nature reserves, there are few practical methods to determine the interior structure of a reserve. A procedure for design of the core zone in reserves is proposed. As a case study, the core zone in Yancheng Biosphere Reserve, People's Republic of China, which was established to preserve the endangered red crowned crane (Grus japonensis) is designed. A statistical habitat model using geographic information system (GIS) is developed to predict crane presence or absence. Based on predicted suitable habitats, the minimum core zone is defined. More suitable habitats can be contained in the designated core zone, and this will be beneficial to the conservation and restoration for crane habitats. 相似文献
12.
Forest stands are the basic planning units of managed forest landscapes, and the structural composition of these units is important for conservation of biodiversity. We present a methodological approach for identification and mapping of important structural and environmental features of forest stands. Based on an analysis of habitats of red-listed species and a synthesis of results from research on spatial distribution of forest species, we developed a habitat inventory approach (Complementary Hotspot Inventory, CHI) that is currently used in forestry planning in Norway. The CHI maps fine-scale hotspots for 12 habitat types that are further classified according to positions along main environmental gradients (productivity and humidity). Consisting of different substrates in different environments, these habitats to a large degree support different species assemblages. By incorporating both the hotspot and the complementary approach, the CHI produces data tuned for later conservation measures. The high spatial resolution of data facilitates the use of conservation measures at different spatial scales, from single-tree retention to forest reserves. A validation test of habitats identified by CHI showed that the density of red-listed species was four times that of randomly selected old forests. 相似文献
13.
The expansion of human activities into rural areas and natural landscapes has resulted in widespread increases in the abundance of synanthropic species that threaten rarer native species. Quantitative assessments of how much impacts need to be reduced to reach acceptable levels of risk to the affected species are rarely conducted prior to the implementation of control measures, and it is perhaps not surprising that many efforts have not yielded the desired outcome. Here, we used matrix-based population viability analysis models to show that reducing predation by rapidly growing corvid populations on marbled murrelet (Brachyramphus marmoratus) nests likely constitutes an effective means for recovering a declining murrelet population in central California. For example, a modest 40% reduction in predation reduced extinction risk dramatically from 95.8% to 4.6% over 100 years and a 60% reduction resulted in a stable population (λ = 1) when the proportion of breeders, renesting rates, and corvid predation rates were assumed to be 0.77, 0.13, and 0.69, respectively. However, nest predation would only need to be reduced by 40% to produce a stable population if corvid management was coupled with a modest increase in after-hatch-year survival from 0.896 to 0.910. Corvid control resulted in greater gains in murrelet population size when the maximum number of breeders was allowed to increase over the projection period, as might be expected if the amount of old-growth nesting habitat increased over time, but extinction risk was insensitive to the presence of a carrying capacity. Approximately half of known murrelet nests in central California are within 1 km of heavily used campgrounds in a single state park, indicating that significant gains in viability could be achieved by targeting efforts in small areas providing corvid food subsidies. Risk assessments such as ours can provide quantitative prioritization rationale for efforts intended to mitigate the impacts of synanthropic species on threatened species. 相似文献
14.
Conservation efforts often require site or parcel selection strategies that lead to spatially cohesive reserves. Although habitat contiguity is thought to be conducive to the persistence of many sensitive species, availability of funding and suitable land may restrict the extent to which this spatial attribute can be pursued in land management or conservation. Using optimization modeling, we explore the economic and spatial tradeoffs of retaining or restoring grassland habitat in contiguous patches of various sizes near the Chicago metropolitan area. The underlying mathematical construct is the first exact, generalized formulation that directly models spatial contiguity in optimal reserve selection. The construct allows conservation planners to analyze and weigh different minimum contiguous habitat size requirements that are to be used in specific land acquisition or retention projects. 相似文献
15.
Maria Beger Hedley S. Grantham Kerrie A. Wilson Peter J. Mumby Daniel R. Brumbaugh 《Biological conservation》2010,143(3):565-130
Conservation plans are usually developed for regions that encompass only one environmental realm (terrestrial, freshwater or marine) because of logistical, institutional and political constraints. This is inadequate because these realms often interact through processes that form, utilize and maintain interfaces or connections, which are essential for the persistence of some species and ecosystem functions. We present a conceptual framework for systematic conservation prioritization that explicitly accounts for the connectivity between the terrestrial, marine, and freshwater realms. We propose a classification of this connectivity that encompasses: (1) narrow interfaces, such as riparian strips; (2) broad interfaces, such as estuaries; (3) constrained connections, such as corridors of native vegetation used by amphibians to move between natal ponds and adult habitat; and (4) diffuse connections, such as the movements of animals between breeding and feeding habitats. We use this taxonomy of inter-realm connectivity to describe existing and new spatial conservation prioritization techniques that aim to promote the persistence of processes that operate between realms. 相似文献
16.
A researcher’s perception of a target species’ landscape strongly influences the design of habitat studies conducted at broad spatial scales. Consequently, researcher-dependent perceptions may misguide conservation efforts. Although the life histories of some crayfish (i.e., primary burrowers) are centered on a fossorial existence independent of surface water, all North American crayfish are viewed in an aquatic context. This paradigm restricts the range of habitats that are typically sampled and managed for crayfish conservation. This study used presence/absence of the primary burrower Distocambarus crockeri at 137 locations within the Long Cane Ranger District of the Sumter National Forest, South Carolina, USA, to model the habitat association of the species across a GIS-based landscape. Logistic regression indicated that D. crockeri presence was most strongly associated with a terrestrial habitat defined by a set of morphologically similar soils located along ridge tops. Furthermore, the species was negatively associated with aquatic habitats such as streams and floodplains. The results indicate that D. crockeri is a terrestrial habitat specialist and should be modeled and managed at the landscape as a terrestrial organism. When viewed as a subset of the total United States cambarid fauna, primary burrowers are disproportionately imperiled. Primary burrowers comprise only 15% of the total crayfish fauna, while they account for 32% of those crayfish ranked critically imperiled. Habitat loss and an aquatic bias that restricted sampling to aquatic and semi-aquatic habitats might explain the group’s disproportionate imperilment. 相似文献
17.
An effective nature reserve network design should reflect the ecological requirements of target species, while simultaneously considering costs. In this study, we propose a design method that considers the ecological role of the spatial arrangement of reserve sites in relation to the long-term persistence of metapopulations of the target species. We apply our design method to an amphibian metapopulation, which illustrates how varying the emphasis on the importance of design factors can affect estimated metapopulation persistence. Comparisons among reserve design methods show that considering the ecological function, rather than generic spatial rules, of the spatial location of reserve sites may be more likely to support species survival. A piecemeal treatment or mechanistic application of spatial rules in reserve design may be subject to the risk of not producing the most effective reserve network, and in some cases may even compromise the conservation objective which could be achieved otherwise. 相似文献
18.
The protection of exploited species offered by marine reserves is maximised if individual fish live within the boundaries of the reserve for most of their lives. The direct benefit of this protection, the so called ‘reserve effect’, is the build-up of biomass through an increase in individual numbers and size. This effect can take several years depending on the life history traits of the target species. However, empirical studies on individual fish spatial behaviour at temporal scales long enough to be compatible with that of invoking the reserve effect are still virtually lacking. We studied the inter-annual patterns of habitat use of the dusky grouper (Epinephelusmarginatus), an endangered reef fish predator, using passive acoustic telemetry inside and around a small marine reserve in the Azores, mid-north Atlantic. All 11 individuals resided in the reserve year-round for up to 5 years. During these periods, fish were detected nearly every day and utilised stable core activity areas. Two smaller fish apparently abandoned the area after some time, probably relocating outside the reserve. Our results indicate that even small marine reserves can promote the long-term recovery of some endangered species if the long-term behaviour (i.e. site fidelity) of individuals is appropriate. This result bears direct implications for most existing coastal marine reserves, given that they fall into the small size range and many overexploited reef fish species may be highly site attached. 相似文献
19.
Xiongwen Chen Bai-Lian Li Thomas A. Scott John T. Rotenberry 《Biological conservation》2005,124(2):169-175
Analysis of the spatial distribution of all species of conservation importance within a region is necessary to augment reserve selection strategies and habitat management in biodiversity conservation. In this study, we analyzed the spatial aggregation, spatial association, and vegetation types of point occurrence data collected from museum and herbaria records for rare, special concern, threatened, and endangered species of plants, reptiles, mammals, and birds in western Riverside County in southern California, USA. All taxa showed clumped distributions, with aggregation evident below 14 km for plants, 12 km for reptiles, 2 km for mammals, and 10 km for birds. In addition, all combinations of the different species groups showed high positive spatial association. The Santa Rosa Plateau exhibited the highest number of rare, special concern, threatened, and endangered species, and shrubland (coastal sage and chaparral) was the vegetation type inhabited by the most species. Local land use planning, zoning and reserve design should consider the spatial aggregation within and between species to determine the appropriate scale for conservation planning. The higher spatial association between species groups in this study may indicate interdependence between different species groups or shared habitat requirements. It is important to maintain diverse communities due to potential interdependence. The results of the study indicate that concentrating preservation efforts on areas with the highest number of species of concern and the restoration of native shrublands are the most appropriate actions for multiple species habitat conservation in this area. 相似文献
20.
Marine protected areas (MPAs) are increasingly envisaged as a tool to manage coastal ecosystems and fisheries. Assessment of their performance with respect to management objectives is therefore important. A number of MPAs provided conservation benefits for fished species. Observed benefits do not apply to all species at all times, and responses to protection are also highly variable among fish taxa. Among the many empirical studies on marine reserves, only a few designs considered ‘before and after data’ and spatial variation. In this paper, we are interested in assessing the effect of a no-take reserve on the reef fish assemblage in a northwestern Mediterranean example. Data were obtained from a three-year survey using underwater visual censuses (UVC), before and after MPA establishment. Permutational multivariate analysis of variance (PERMANOVA) and multivariate regression trees (MRT) were used to evaluate the effects of reserve protection on the reef fish assemblage, while accounting for habitat. Modelled biological responses were abundances and diversity indices calculated at different levels of the assemblage. Significant effects were found for many of these metrics. In addition to PERMANOVA, univariate models provided more insight into the magnitude and direction of effects. The most sensitive metrics were related to large species and species targeted by fishing. These results may be used to choose the metrics that are more suitable as community-based indicators of MPA impact in the perspective of monitoring programs. 相似文献