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Gillnet fisheries are widely thought to pose a conservation threat to many populations of marine mammals, seabirds, and turtles. Gillnet fisheries also support a significant proportion of small-scale fishing communities worldwide. Despite a large number of studies on protected-species bycatch in recent decades, relatively few have examined the underlying causes of bycatch and fewer still have considered the issue from a multitaxon perspective. We used 3 bibliographic databases and one search engine to identify studies by year of publication and taxon. The majority of studies on the mechanisms of gillnet bycatch are not accessible through the mainstream published literature. Many are reported in technical papers, government reports, and university theses. We reviewed over 600 published and unpublished studies of bycatch in which causal or correlative factors were considered and identified therein 28 environmental, operational, technical, and behavioral factors that may be associated with high or low bycatch rates of the taxa. Of the factors considered, 11 were associated with potential bycatch reduction in 2 out of the 3 taxa, and 3 factors (water depth, mesh size, and net height) were associated with trends in bycatch rate for all 3 taxa. These findings provide a basis to guide further experimental work to test hypotheses about which factors most influence bycatch rates and to explore ways of managing fishing activities and improving gear design to minimize the incidental capture of species of conservation concern while ensuring the viability of the fisheries concerned. Se cree extensamente que las pesquerías que utilizan redes significan una amenaza para la conservación de muchas poblaciones de mamíferos marinos, aves marinas y tortugas. Las pesquerías con redes también sustentan a una proporción significativa de comunidades pesqueras a nivel mundial. A pesar del gran número de estudios sobre la captura incidental de especies protegidas realizados en la década reciente, relativamente pocos han examinado las causas subyacentes de la captura incidental y muchos menos han considerado el tema desde una perspectiva multi-taxón. Utilizamos tres bases de datos bibliográficas y un buscador para identificar a los estudios por año de publicación y por taxón. La mayoría de los estudios sobre los mecanismos de la captura incidental con redes de pesca no son accesibles por medio de la literatura publicada convencionalmente. Muchos estudios están reportados en artículos técnicos, reportes del gobierno y tesis universitarias. Revisamos más de 600 estudios publicados y no-publicados sobre la captura incidental, en los que los factores correlativos o causales fueron considerados e identificados dentro de 28 factores ambientales, operativos, técnicos y de comportamiento que pueden asociarse con las tasas altas o bajas de captura colateral de los taxa. De los factores considerados, once estuvieron asociados con la reducción potencial de la captura incidental en dos de los tres taxa, y tres factores (profundidad del agua, tamaño de la malla y altura de la red) estuvieron asociados con las tendencias de la tasa de captura incidental para los tres taxa. Estos hallazgos proporcionan una base para guiar más allá al trabajo experimental para probar hipótesis sobre cuáles factores influyen sobre las tasas de captura incidental y para explorar formas de manejo de las actividades de pesca y el mejoramiento del diseño del equipo para minimizar la captura incidental de las especies de interés de conservación, a la vez que se asegura la viabilidad de las pesquerías involucradas.

Networks of sites of high importance for conservation of biological diversity are a cornerstone of current conservation strategies but are fixed in space and time. As climate change progresses, substantial shifts in species' ranges may transform the ecological community that can be supported at a given site. Thus, some species in an existing network may not be protected in the future or may be protected only if they can move to sites that in future provide suitable conditions. We developed an approach to determine appropriate climate-change adaptation strategies for individual sites within a network that was based on projections of future changes in the relative proportions of emigrants (species for which a site becomes climatically unsuitable), colonists (species for which a site becomes climatically suitable), and persistent species (species able to remain within a site despite the climatic change). Our approach also identifies key regions where additions to a network could enhance its future effectiveness. Using the sub-Saharan African Important Bird Area (IBA) network as a case study, we found that appropriate conservation strategies for individual sites varied widely across sub-Saharan Africa, and key regions where new sites could help increase network robustness varied in space and time. Although these results highlight the potential difficulties within any planning framework that seeks to address climate-change adaptation needs, they demonstrate that such planning frameworks are necessary, if current conservation strategies are to be adapted effectively, and feasible, if applied judiciously. Las redes de sitios de gran importancia para la conservación de la diversidad biológica son una piedra angular de las estrategias actuales de conservación pero están fijas en espacio y tiempo. A medida que el cambio climático progresa, cambios sustanciales en los rangos de distribución de las especies pueden transformar la comunidad ecológica que puede ser soportada en un sitio determinado. Por lo tanto, algunas especies en una red existente pueden no ser protegidas en el futuro o pueden ser protegidas solo si se mueven a sitios que proporcionen condiciones adecuadas en el futuro. Desarrollamos un método para determinar las estrategias de adaptación al cambio climático para sitios individuales dentro de una red que se basó en las proyecciones de cambios futuros en las proporciones relativas de emigrantes (especies para las que un sitio se vuelve inadecuado climáticamente), colonizadoras (especies para las que un sitio se vuelve adecuado climáticamente) y especies persistentes (especies capaces de permanecer en un sitio no obstante el cambio climático). Nuestro método también identifica regiones clave donde adiciones a una red podrían reforzar su efectividad en el futuro. Utilizando la red del Área de Importancia para las Aves sub-Sahariana como un caso de estudio, encontramos que las estrategias de conservación apropiadas para sitios individuales variaron ampliamente en África sub-Sahariana, y regiones clave donde nuevos sitios podrían ayudar a incrementar la robustez de la red variaron en espacio y tiempo. Aunque estos resultados resaltan las dificultades potenciales de cualquier marco de planificación que busque abordar las necesidades de adaptación al cambio climático, demuestran que tales marcos de planificación son necesarios, para que las estrategias de conservación actuales sean adaptadas efectivamente, y sean factibles, si son aplicadas juiciosamente.

Weight-length relations of fishes are useful for estimation of biomass from length observations, e.g., in fisheries or conservation research. Here we provide some guidance to authors of such papers, in order to facilitate the publication and review process

Multiple shoot formation was induced in vitro on nodal sections excised from adult \"palo gordo\" plants of Vasconcellea chilensis ex Carica chilensis, in the presence of relatively high levels of thidiazuron (TDZ), indole-3- acetic acid (IAA) and organic addenda included in the WPM formulation including casein hydrolysate, adenine sulfate and cystein. Multiple shoots appeared simultaneously in strands or clusters on the surface of the explants; usually two or more clusters with new shoots were initiated, all showing synchronous growth. In subculture, in the presence of indole-3-butyric acid (IBA) as single hormone, root formation did not take place; the shoots turned green instead, evidenced elongation and development of new shoots at the base of the explants. Other explants, such as petioles and leaf sections exhibited callus initiation upon the vascular system after 4-5 weeks; however, this tissue turned brown later on and died. Key words: papaya silvestre, palo gordo, monte gordo, endemic, endangered, in vitro, multiple shoots La formación de brotes múltiples bajo condiciones in vitro pudo ser inducida en secciones nodales de plantas adultas de \"palo gordo\" Vasconcellea chilensis ex Carica chilensis, mediante el uso de altos niveles de tidiazuron (TDZ), ácido indolacético (AIA) y en presencia de addenda orgánica (hidrolizado enzimático de caseína, sulfato de adenina y cisteína) incluidas en el medio nutritivo \"WPM\". Dichos brotes se iniciaron sincrónicamente, en forma de agregados compactos y/o en hileras, sobre la superficie del explante. En subcultivo, los brotes evidenciaron elongación tornando a color verde, con iniciación de nuevos brotes desde la base y, a pesar de la presencia de ácido indolbutírico (AIB) como única hormona, no desarrollaron raíces. Otros explantes ensayados, tales como pecíolos, no evidenciaron respuesta. Solo secciones de hojas iniciaron la formación de una estructura compacta o callo a nivel de la nervadura principal transcurridas 4-5 semanas, tornándose pardo luego y con posterior muerte tisular.Palabras clave: papaya silvestre, palo gordo, monte gordo, endémicas, en peligro de extinción, in vitro, brotes múltiples.

Populations of mountain golden heather (Hudsonia montana), a threatened North Carolina shrub, are declining due to the suppression of natural fires and increased trampling by hikers and campers. Consequently, proposed management strategies have focused on conducting controlled burns and restricting human traffic. To help design an optimal management plan, we used demographic data from a 5-year field study of H. montana--which included a controlled burn--to construct size-based population projection matrices. Using these matrices, we projected the consequences of instituting controlled burns and hiking and camping restrictions separately and in tandem. We also determined the burn frequency that would maximize H. montana's population growth rate. Finally, we used a stochastic model to determine how environmental fluctuations could alter the efficacy of conservation measures. Our results suggest that, although neither burning nor trampling reduction alone can reverse H. montana's decline, a judicious combination of the two has an excellent chance of doing so. A burn frequency of once every 6-8 years should maximize H. montana's population growth, although the interburn interval could be increased to 12-16 years without significantly jeopardizing the success of the management plan. Our results show that, even with the limited data available, size-based projection matrix models can be useful tools for identifying promising combinations of multiple management strategies for most threatened plants.

In Poland Equisetum telmateia Ehrh. is a sub-mountainous species. In lowland regions it is fairly rare. A highly populated site of this species is noted near the village of Klasztorne in Western Pomerania. The investigation was carried out in the year 2006. In the investigated area giant horsetail chiefly occurs in forest phytocenoses on embankments and flood terraces of the river Kaczynka valley (Fraxino-Alnetum W.Mat. 1952, Ribeso nigri-Alnetum Sol.Górn. (1975) 1987). Very abundantly it grows in non-forest phytocenoses where on the river bank its fields are found on forest outskirts encroaching the area of a wet field (community of the Aegopodion podagrariae alliance). Horsetail shows different cover in the individual patches of phytocoenoses. However, it does not depend on the type of the phytocoenosis being directly associated with the degree of solar exposure.

Land managers often suggest fencing to protect rare plant species from being trampled in heavily used recreation areas, but there are few documented examples of the efficacy of this strategy. In a 7-year demographic study we examined the reproduction, survival, and long-term viability of the endangered sentry milk-vetch (Astragalus cremnophylax var. cremnophylax) before and after protection from trampling. Demographic monitoring and population viability analyses indicated that the population has fluctuated during the 7 years. Before protection the population declined: 26% of individuals died, mortality surpassed natality, and age of first reproduction was significantly older than post-protection. Fifty-eight percent of the population was severely damaged. Population viability analyses of pre-protection years predicted that the population would go extinct within 100 years. Since protection, the population stabilized, grew, and declined again. Seedlings reached reproductive maturity more quickly. Recruitment increased and peaked in 1993 coincident with abundant precipitation, but again declined in 1994. The total numbers of undamaged plants surpassed the numbers of damaged plants. Models of the post-protection population predict stability. Multiple-linear regression analysis indicated that winter and spring precipitation were significantly correlated with lambda. Both \"good\" and \"bad\" climatic conditions occurred during the pre- and post-protection periods. Because of small population size and depauperate genetic diversity, climate will continue to influence population growth. Nevertheless, models indicate that where trampling and bad climatic conditions were coupled, extinction was accelerated. Recovery of sentry milk-vetch will depend on continued protection, augmentation, and environmental factors, although risk of extinction remains very high.

Designing a reserve system for a threatened territorial species such as the Northern Spotted Owl requires the balancing of biological necessity against economic reality. The Spotted Owl conservation plan and the Pacific Northwest timber industry are in conflict because both demand large areas of mature and old-growth coniferous forest. The primary focus of this paper is the efficient design of a reserve system for territorial species with obligate juvenile dispersal. We examine the relationship between the degree of aggregation of suitable owl habitat, the level of occupancy of that habitat by pairs of Spotted Owls, and the likelihood of owl persistence given different amounts and spatial arrangements of suitable habitat across the landscape. We develop a population model for Spotted Owls that includes an abstracted forest landscape where suitable owl habitat is arrayed in clusters embedded in a matrix not suitable for owl habitation. We conclude from our study of this model that, for any given fraction of the landscape set aside in reserves, the level of occupancy (efficiency of use) of that area will increase as the aggregation of suitable habitat increases. After the reserves reach a size that includes territories for 20 to 25 owl pairs, however, there are diminishing returns from further increases. Preserving connectivity and increasing the geographical extent of the reserve begin to outweigh increased size in importance in insuring the long-term viability of the species.