RESUMEN
The optimal design of reserve networks and fisheries closures depends on species occurrence information and knowledge of how anthropogenic impacts interact with the species concerned. However, challenges in surveying mobile and cryptic species over adequate spatial and temporal scales can mask the importance of particular habitats, leading to uncertainty about which areas to protect to optimize conservation efforts. We investigated how telemetry-derived locations can help guide the scale and timing of fisheries closures with the aim of reducing threatened species bycatch. Forty juvenile speartooth sharks (Glyphis glyphis) were monitored over 22 months with implanted acoustic transmitters and an array of hydrophone receivers. Using the decision-support tool Marxan, we formulated a permanent fisheries closure that prioritized areas used more frequently by tagged sharks and considered areas perceived as having high value to fisheries. To explore how the size of the permanent closure compared with an alternative set of time-area closures (i.e., where different areas were closed to fishing at different times of year), we used a cluster analysis to group months that had similar arrangements of selected planning units (informed by shark movements during that month) into 2 time-area closures. Sharks were consistent in their timing and direction of migratory movements, but the number of tagged sharks made a big difference in the placement of the permanent closure; 30 individuals were needed to capture behavioral heterogeneity. The dry-season (May-January) and wet-season (February-April) time-area closures opened 20% and 25% more planning units to fishing, respectively, compared with the permanent closure with boundaries fixed in space and time. Our results show that telemetry has the potential to inform and improve spatial management of mobile species and that the temporal component of tracking data can be incorporated into prioritizations to reduce possible impacts of spatial closures on established fisheries.
Uso de Información de Movimiento Basada en Individuos para Identificar las Prioridades de Conservación Espacial para las Especies Móviles Resumen El diseño óptimo de redes de reservas y los cierres de pesquerías depende de la información sobre la presencia de especies y del conocimiento sobre cómo los impactos antropogénicos interactúan con las especies afectadas. Sin embargo, las dificultades que existen al monitorear especies móviles y crípticas en escalas espaciales y temporales adecuadas pueden enmascarar la importancia de los hábitats particulares, lo que resulta en incertidumbre con respecto a cuáles áreas proteger para optimizar los esfuerzos de conservación. Investigamos cómo las ubicaciones derivadas de la telemetría pueden ayudar a guiar la escala y el momento justo del cierre de las pesquerías con el objetivo de reducir la captura accesoria de especies amenazadas. Se monitorearon 40 tiburones lanza juveniles (Glyphis glyphis) durante 22 meses con transmisores acústicos implantados y una selección de receptores hidrofónicos. Con la herramienta de apoyo para la toma de decisiones Marxan, formulamos un cierre de pesquerías permanente que priorizó las áreas usadas con frecuencia por los tiburones marcados y que consideraba a las áreas percibidas como altamente valiosas para las pesquerías. Para explorar cómo el tamaño del cierre permanente se comparaba con un conjunto de cierres con áreas y tiempos alternativos (es decir, donde las áreas se cerraron a la pesca en diferentes momentos del año) usamos un análisis de clúster para agrupar los meses que tuvieron arreglos similares a las unidades de planeación seleccionadas (informadas por el movimiento de los tiburones durante ese mes) en dos cierres de tiempo-área. Los tiburones fueron consistentes en el tiempo y dirección de sus movimientos migratorios, pero el número de tiburones marcados generó una gran diferencia en la ubicación del cierre permanente; se necesitaron 30 individuos para capturar la heterogeneidad del comportamiento. Los cierres de tiempo-área de la temporada de secas (mayo - enero) y la de lluvias (febrero - abril) abrieron a la pesca un 20% y 25% más de unidades de planeación, respectivamente, en comparación con el cierre permanente con barreras fijas en el tiempo y el espacio. Nuestros resultados muestran que la telemetría tiene el potencial para informar y mejorar el manejo espacial de las especies móviles y que el componente temporal de los datos de rastreo puede ser incorporado a las priorizaciones para reducir los posibles impactos del manejo sobre las pesquerías establecidas.
Asunto(s)
Conservación de los Recursos Naturales , Tiburones , Animales , Ecosistema , Especies en Peligro de Extinción , Explotaciones PesquerasRESUMEN
Coral reefs are threatened by human activities on both the land (e.g., deforestation) and the sea (e.g., overfishing). Most conservation planning for coral reefs focuses on removing threats in the sea, neglecting management actions on the land. A more integrated approach to coral reef conservation, inclusive of land-sea connections, requires an understanding of how and where terrestrial conservation actions influence reefs. We address this by developing a land-sea planning approach to inform fine-scale spatial management decisions and test it in Fiji. Our aim is to determine where the protection of forest can deliver the greatest return on investment for coral reef ecosystems. To assess the benefits of conservation to coral reefs, we estimate their relative condition as influenced by watershed-based pollution and fishing. We calculate the cost-effectiveness of protecting forest and find that investments deliver rapidly diminishing returns for improvements to relative reef condition. For example, protecting 2% of forest in one area is almost 500 times more beneficial than protecting 2% in another area, making prioritization essential. For the scenarios evaluated, relative coral reef condition could be improved by 8-58% if all remnant forest in Fiji were protected rather than deforested. Finally, we determine the priority of each coral reef for implementing a marine protected area when all remnant forest is protected for conservation. The general results will support decisions made by the Fiji Protected Area Committee as they establish a national protected area network that aims to protect 20% of the land and 30% of the inshore waters by 2020. Although challenges remain, we can inform conservation decisions around the globe by tackling the complex issues relevant to integrated land-sea planning.
Asunto(s)
Conservación de los Recursos Naturales/métodos , Arrecifes de Coral , Árboles , Animales , Análisis Costo-Beneficio , Fiji , Explotaciones Pesqueras , Peces , Actividades Humanas , Contaminantes Químicos del AguaRESUMEN
1. The estuarine crocodile (Crocodylus porosus) is the world's largest living reptile. It predominately inhabits freshwater and estuarine habitats, but widespread geographic distribution throughout oceanic islands of the South-east Pacific suggests that individuals undertake sizeable ocean voyages. 2. Here we show that adult C. porosus adopt behavioural strategies to utilise surface water currents during long-distance travel, enabling them to move quickly and efficiently over considerable distances. 3. We used acoustic telemetry to monitor crocodile movement throughout 63 km of river, and found that when individuals engaged in a long-distance, constant direction journey (>10 km day(-1)), they would only travel when current flow direction was favourable. Depth and temperature measurements from implanted transmitters showed that they remained at the water surface during travel but would dive to the river substratum or climb out on the river bank if current flow direction became unfavourable. 4. Satellite positional fixes from tagged crocodiles engaged in ocean travel were overlaid with residual surface current (RSC) estimates. The data showed a strong correlation existed between the bearing of the RSC and that of the travelling crocodile (r(2) = 0.92, P < 0.0001). 5. The study demonstrates that C. porosus dramatically increase their travel potential by riding surface currents, providing an effective dispersal strategy for this species.
Asunto(s)
Caimanes y Cocodrilos/fisiología , Migración Animal , Movimientos del Agua , Sistemas de Identificación Animal , Animales , Océanos y Mares , Nave Espacial , TelemetríaRESUMEN
The Fifth World Parks Congress in Durban, South Africa, announced in September 2003 that the global network of protected areas now covers 11.5% of the planet's land surface. This surpasses the 10% target proposed a decade earlier, at the Caracas Congress, for 9 out of 14 major terrestrial biomes. Such uniform targets based on percentage of area have become deeply embedded into national and international conservation planning. Although politically expedient, the scientific basis and conservation value of these targets have been questioned. In practice, however, little is known of how to set appropriate targets, or of the extent to which the current global protected area network fulfils its goal of protecting biodiversity. Here, we combine five global data sets on the distribution of species and protected areas to provide the first global gap analysis assessing the effectiveness of protected areas in representing species diversity. We show that the global network is far from complete, and demonstrate the inadequacy of uniform--that is, 'one size fits all'--conservation targets.
Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales/estadística & datos numéricos , Animales , Conservación de los Recursos Naturales/métodos , Geografía , Cooperación Internacional , Especificidad de la Especie , Factores de TiempoRESUMEN
Large-scale catastrophic events, although rare, lie generally beyond the control of local management and can prevent marine reserves from achieving biodiversity outcomes. We formulate a new conservation planning problem that aims to minimize the probability of missing conservation targets as a result of catastrophic events. To illustrate this approach we formulate and solve the problem of minimizing the impact of large-scale coral bleaching events on a reserve system for the Great Barrier Reef, Australia. We show that by considering the threat of catastrophic events as part of the reserve design problem it is possible to substantially improve the likely persistence of conservation features within reserve networks for a negligible increase in cost. In the case of the Great Barrier Reef, a 2% increase in overall reserve cost was enough to improve the long-run performance of our reserve network by >60%. Our results also demonstrate that simply aiming to protect the reefs at lowest risk of catastrophic bleaching does not necessarily lead to the best conservation outcomes, and enormous gains in overall persistence can be made by removing the requirement to represent all bioregions in the reserve network. We provide an explicit and well-defined method that allows the probability of catastrophic disturbances to be included in the site selection problem without creating additional conservation targets or imposing arbitrary presence/absence thresholds on existing data. This research has implications for reserve design in a changing climate.
Asunto(s)
Conservación de los Recursos Naturales/métodos , Desastres , Ecosistema , Animales , Australia , Biología Marina , Modelos Biológicos , Océanos y Mares , Objetivos Organizacionales , Técnicas de PlanificaciónRESUMEN
Creating large conservation zones in remote areas, with less intense stakeholder overlap and limited environmental information, requires periodic review to ensure zonation mitigates primary threats and fill gaps in representation, while achieving conservation targets. Follow-up reviews can utilise improved methods and data, potentially identifying new planning options yielding a desirable balance between stakeholder interests. This research explored a marine zoning system in north-west Australia-a biodiverse area with poorly documented biota. Although remote, it is economically significant (i.e. petroleum extraction and fishing). Stakeholder engagement was used to source the best available biodiversity and socio-economic data and advanced spatial analyses produced 765 high resolution data layers, including 674 species distributions representing 119 families. Gap analysis revealed the current proposed zoning system as inadequate, with 98.2% of species below the Convention on Biological Diversity 10% representation targets. A systematic conservation planning algorithm Maxan provided zoning options to meet representation targets while balancing this with industry interests. Resulting scenarios revealed that conservation targets could be met with minimal impacts on petroleum and fishing industries, with estimated losses of 4.9% and 7.2% respectively. The approach addressed important knowledge gaps and provided a powerful and transparent method to reconcile industry interests with marine conservation.
Asunto(s)
Algoritmos , Biodiversidad , Conservación de los Recursos Naturales , Explotaciones Pesqueras , Animales , Australia , Ecosistema , Ambiente , Océanos y Mares , Industria del Petróleo y Gas/métodosRESUMEN
Conservation planning is the process of locating, configuring, implementing and maintaining areas that are managed to promote the persistence of biodiversity and other natural values. Conservation planning is inherently spatial. The science behind it has solved important spatial problems and increasingly influenced practice. To be effective, however, conservation planning must deal better with two types of change. First, biodiversity is not static in time or space but generated and maintained by natural processes. Second, humans are altering the planet in diverse ways at ever faster rates.