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1.
Conserv Biol ; 33(3): 601-611, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30461065

RESUMO

Reintroductions are important components of conservation and recovery programs for rare plant species, but their long-term success rates are poorly understood. Previous reviews of plant reintroductions focused on short-term (e.g., ≤3 years) survival and flowering of founder individuals rather than on benchmarks of intergenerational persistence, such as seedling recruitment. However, short-term metrics may obscure outcomes because the unique demographic properties of reintroductions, including small size and unstable stage structure, could create lags in population growth. We used time-to-event analysis on a database of unusually well-monitored and long-term (4-28 years) reintroductions of 27 rare plant species to test whether life-history traits and population characteristics of reintroductions create time-lagged responses in seedling recruitment (i.e., recruitment time lags [RTLs]), an important benchmark of success and indicator of persistence in reintroduced populations. Recruitment time lags were highly variable among reintroductions, ranging from <1 to 17 years after installation. Recruitment patterns matched predictions from life-history theory with short-lived species (fast species) exhibiting consistently shorter and less variable RTLs than long-lived species (slow species). Long RTLs occurred in long-lived herbs, especially in grasslands, whereas short RTLs occurred in short-lived subtropical woody plants and annual herbs. Across plant life histories, as reproductive adult abundance increased, RTLs decreased. Highly variable RTLs were observed in species with multiple reintroduction events, suggesting local processes are just as important as life-history strategy in determining reintroduction outcomes. Time lags in restoration outcomes highlight the need to scale success benchmarks in reintroduction monitoring programs with plant life-history strategies and the unique demographic properties of restored populations. Drawing conclusions on the long-term success of plant reintroduction programs is premature given that demographic processes in species with slow life-histories take decades to unfold.


Efectos de la Historia de Vida y la Reproducción sobre las Demoras en el Tiempo de Reclutamiento en la Reintroducción de Plantas Raras Resumen Las reintroducciones son componentes importantes de los programas de conservación y recuperación de especies raras de plantas, pero las tasas de éxito a largo plazo cuentan con muy poco entendimiento. Las revisiones previas de las reintroducciones de plantas se han enfocado en la supervivencia a corto plazo (p. ej.: ≤ 3 años) y en el florecimiento de individuos fundadores en lugar de enfocarse en puntos de referencia para la persistencia inter-generacional, como el reclutamiento de plántulas. Sin embargo, las medidas a corto plazo pueden ocultar los resultados ya que las propiedades demográficas únicas de las reintroducciones, incluyendo el menor tamaño y la estructura inestable de estadio, podrían crear demoras en el crecimiento poblacional. Usamos un análisis de tiempo-para-evento en una base de datos de reintroducciones inusualmente bien monitoreadas y de largo plazo (4-28 años) de 27 especies raras de plantas para probar si los atributos de la historia de vida y las características poblacionales de la reintroducción crean respuestas con demoras temporales en el reclutamiento de plántulas (es decir, demoras temporales en el reclutamiento), un punto de referencia importante para el éxito y un indicador de la persistencia en poblaciones reintroducidas. Las demoras temporales de reclutamiento (RTLs, en inglés) fueron muy variables entre las reintroducciones, abarcando desde <1 hasta 17 años después de la instalación. Los patrones de reclutamiento se acoplaron a las predicciones de la teoría de historias de vida, donde las especies de vida corta (especies rápidas) exhibieron RTLs consistentemente más cortas y menos variables que las especies de vida larga (especies lentas). Las RTLs largas ocurrieron en hierbas de vida larga, especialmente en los pastizales, mientras que las RTLs cortas ocurrieron en plantas leñosas subtropicales de vida corta y en hierbas anuales. En todas las historias de vida de las plantas, conforme incrementó la abundancia de adultos reproductivos, las RTLs disminuyeron. Se observaron RTLs altamente variables en las especies con eventos de reintroducción múltiples, lo que sugiere que los procesos locales son igual de importantes que la estrategia de historia de vida para determinar los resultados de las reintroducciones. Las demoras temporales en los resultados de restauración resaltan la necesidad de poner a escala los puntos de referencia de éxito en los programas de monitoreo de reintroducciones que tengan estrategias de historia de vida de las plantas y las propiedades demográficas únicas de las poblaciones restauradas. La obtención de conclusiones sobre el éxito a largo plazo de los programas de reintroducción de plantas es algo prematuro ya que los procesos demográficos de especies con historias de vida lentas tardan décadas en desarrollarse.


Assuntos
Conservação dos Recursos Naturais , Reprodução , Demografia , Plantas , Crescimento Demográfico
2.
PLoS One ; 6(8): e23047, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21853066

RESUMO

BACKGROUND: Coral reefs are facing increasing pressure from natural and anthropogenic stressors that have already caused significant worldwide declines. In January 2010, coral reefs of Florida, United States, were impacted by an extreme cold-water anomaly that exposed corals to temperatures well below their reported thresholds (16°C), causing rapid coral mortality unprecedented in spatial extent and severity. METHODOLOGY/PRINCIPAL FINDINGS: Reef surveys were conducted from Martin County to the Lower Florida Keys within weeks of the anomaly. The impacts recorded were catastrophic and exceeded those of any previous disturbances in the region. Coral mortality patterns were directly correlated to in-situ and satellite-derived cold-temperature metrics. These impacts rival, in spatial extent and intensity, the impacts of the well-publicized warm-water bleaching events around the globe. The mean percent coral mortality recorded for all species and subregions was 11.5% in the 2010 winter, compared to 0.5% recorded in the previous five summers, including years like 2005 where warm-water bleaching was prevalent. Highest mean mortality (15%-39%) was documented for inshore habitats where temperatures were <11°C for prolonged periods. Increases in mortality from previous years were significant for 21 of 25 coral species, and were 1-2 orders of magnitude higher for most species. CONCLUSIONS/SIGNIFICANCE: The cold-water anomaly of January 2010 caused the worst coral mortality on record for the Florida Reef Tract, highlighting the potential catastrophic impacts that unusual but extreme climatic events can have on the persistence of coral reefs. Moreover, habitats and species most severely affected were those found in high-coral cover, inshore, shallow reef habitats previously considered the "oases" of the region, having escaped declining patterns observed for more offshore habitats. Thus, the 2010 cold-water anomaly not only caused widespread coral mortality but also reversed prior resistance and resilience patterns that will take decades to recover.


Assuntos
Antozoários/fisiologia , Temperatura Baixa , Recifes de Corais , Água do Mar , Animais , Florida , Geografia , Oceanos e Mares , Análise de Sobrevida , Taxa de Sobrevida
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