Abstract Background: Mangrove plant species have distinctive anatomical and physiological responses to cope with a wide range of salinities and inundations. These strategies pertain a safe and efficient water use and transport, essential for survival. Questions: How are the anatomical and physiological attributes of the hydraulic architecture of seedlings and adults of Rhizophora mangle? what are the changes in hydraulic architecture of seedlings and adults of R. mangle in contrasting microenvironments? Studied species: Rhizophora mangle L. (Rhizophoraceae). Study site and dates: Scrub and fringe mangroves in Ria Celestún Biosphere Reserve, during the rainy season of 2013 (July to October). Methods: Hydraulic conductivity and leaf water potential, as well as xylem vessel density, length, transversal and radial diameter, and area were measured for seedlings and adults from both sites. The prevailing environmental conditions (soil water potential, salinity, photon flux density, air temperature and relative humidity) were also characterized. Results: A safer hydraulic conduction system, with narrow and more grouped vessels, was observed in seedlings than in adults of R. mangle in both sites. Adult individuals from the scrub mangrove, in the hyper saline microenvironment, had a safer hydraulic conduction system than adults in the fringe mangrove. Conclusions: The seedling stage of R. mangle showed a safer hydraulic system than adults in both types of mangroves. However, over time this hydraulic conduction system could become more efficient or remain safe depending on the microenvironment in which individuals are growing.

Resumen Antecedentes: Los manglares presentan respuestas anatómicas y fisiológicas distintivas para enfrentar una amplia variación de condiciones ambientales. Éstas están relacionadas con la seguridad y eficiencia en el uso y transporte del agua para su supervivencia. Preguntas: ¿Cómo son los atributos anatómicos y fisiológicos de la arquitectura hidráulica de las plántulas y los adultos de R. mangle? ¿Cuáles son los cambios en la arquitectura hidráulica de plántulas y adultos de R. mangle, en microambientes contrastantes? Especies de estudio: Rhizophora mangle L. (Rhizophoraceae). Sitio y años de estudio: Manglares chaparros y de franja en la Reserva de la Biósfera Ria Celestún, durante la estación lluviosa de 2013. Métodos: Se realizaron mediciones de la conductividad hidráulica y el potencial hídrico foliar, así como aspectos anatómicos de los vasos del xilema, en plántulas y los adultos de ambos sitios. También se caracterizaron las condiciones ambientales (potencial hídrico del suelo, salinidad, densidad de flujo de fotones, temperatura del aire y humedad relativa del aire). Resultados: El sistema de conducción hidráulica de las plántulas de ambos sitios fue más seguro, con vasos estrechos y más agrupados, que en adultos. Los adultos del manglar chaparro tuvieron un sistema de conducción más seguro que en los adultos del manglar de franja. Conclusiones: Las plántulas de R. mangle mostraron un sistema de conducción hidráulico más seguro que los adultos en ambos tipos de manglar. Sin embargo, con el tiempo, el sistema de conducción puede revertir en un sistema más eficiente o permanecer seguro, dependiendo del microambiente en el que se desarrollen los individuos.

Abstract The aridity and geographic isolation of the region currently occupied by the State of Baja California Sur have determined its status as a sparsely populated region for most of its history, which has allowed the ecosystems therein to remain pristine or little impacted. Nevertheless, the State has not been immune to the global trend of vigorous population growth in coastal regions. This trend became evident in La Paz city since the 1990s (population as of 1995: 158,800; as of 2015: 253,021 inhabitants), caused by a tourism-driven economy that has led to accelerated, unplanned urban sprawling (urban area as of 1995: 44.7 km2; as of 2017: 85.7 km2). The objective of this study was to identify and analyze anthropic effects on the geomorphology and morphodynamics of the coastal zone, starting with the geomorphological reconstruction of the likely original conditions, followed by an analysis of the population growth and economic activities leading to urban expansion, to finally elucidating their effects on and the evolutionary response of the coastal zone. We used linear regression methods for analyzing geomorphological and morphodynamic changes from historical documents, particularly those that are, or can be, georeferenced such as maps, aerial photographs, and satellite images. This allows utilizing both methods over long-term, large (kilometer) spatial scales. Linear regression methods used all the shoreline location data points available to identify changes over time and estimate evolutionary rates. One distinctive advantage of linear regressions is the possibility of using coastlines as delineated from aerial photographs or historical maps, since beach profiles encompassing long-term, large (kilometer) spatial scales are usually not available. The study area comprises two distinct geomorphological units - the alluvial plain and the coastal zone - subject to increasing anthropic activity as evidenced by urban expansion over time. This affects the geomorphological environment, causing major changes in the physical environment, such as fragmentation in parcels and streets, deforestation, and land leveling, as well as the diversion and filling of streambeds. The direct effects of anthropogenic activities on the coastal zone lead to the alteration and partial or total loss of coastal ecosystems such as coastal plains, marshes, mangrove swamps, beaches, and dunes, caused by the construction of tourism infrastructure including hotels, marinas, docks, golf courses, and buildings ranging from residential areas to car junkyards. At the same time, the effects of human activities on the alluvial plain indirectly impact the coastal zone through the reduction of the effective runoff area caused by unabated urban expansion. This, in turn, impairs the sedimentary balance that gave rise to alluvial coastal environments, in which the intensity of the dynamic agents (such as wind, tides, and waves) acting on the coastal zone remained constant. These agents have been acting with the same intensity but, in the absence of sedimentary material, conditions have changed sufficiently to affect the morphodynamics of the coastal fringe of the La Paz lagoon. The evolutionary trend of the La Paz lagoon shows that it has experienced an erosive process at a rate of 0.00227 km2 over 44 years (from 1973 to 2017, or 0.3 m/ year). Paradoxically, the poor or nil urban growth planning is not only causing the loss of the resources that support tourism activities, but is also exacerbating the vulnerability to flooding events in L a Paz city and surrounding suburbs. Therefore, it is crucial to properly weigh the benefits of continuing building hotels, marinas, golf courses, residential areas, and other types of infrastructure, versus those of conserving marshes, mangrove swamps, beaches, and dunes, whose proper use and management would contribute to the sustainable economic and environmental development of the region.

Resumen La ciudad de La Paz no ha sido ajena a las tendencias de crecimiento poblacional que se han dado en las regiones costeras. Crecimiento que se hace evidente a partir de la década de los años noventa del siglo pasado, motivado por una economía basada en la actividad turística, y que se refleja en el acelerado y desordenado incremento de su área urbana. En este contexto se plantea como objetivo analizar el efecto antrópico en la franja y borde costero de la laguna de La Paz, empleando para ello las metodologías de cambios geomorfológicos y morfodinámicos. En el área de estudio se reconocen dos unidades geomorfológicas: llanura aluvial y franja costera, ambas sometidas a una creciente actividad antrópica, lo que genera importantes cambios inherentes al urbanismo. El efecto en la franja costera se refleja con la alteración y pérdida parcial o total de ecosistemas costeros, debido a la construcción de infraestructura turística. Al mismo tiempo, en la llanura aluvial el incremento progresivo del área urbana ha reducido el área de escurrimiento efectivo y aporte sedimentario, modificando el balance que dio origen a los ambientes costeros, ocasionando que las condiciones por falta de material cambien lo suficiente como para reflejarse en la erosión de su línea de costa, que, en una extensión perimetral de 7.1 km en el periodo de 1973 al 2017, registra una tasa de retroceso de -0.00227 km2 en 44 años (0.3 m/año).

RESUMEN En este estudio se describe la abundancia, composición por tallas y crecimiento relativo de organismos juveniles de la jaiba Callinectes sapidus en el estuario ciego Laguna El Llano, Veracruz, México; las jaibas se muestrearon desde mayo de 2013 hasta mayo de 2014 en ocho sitios, cuatro sin vegetación, con sedimentos arenosos y aguas claras cercanos a la boca estuarina, los restantes con vegetación de manglar, sedimentos lodosos y aguas turbias. Se registraron las variables hidrológicas pH, temperatura, oxígeno disuelto, turbidez y salinidad. Se recolectaron 276 jaibas (235 machos y 41 hembras), la abundancia fue mayor (91,3 %) en los sitios cercanos a manglares, sedimentos lodosos y aguas turbias; la abundancia no se relacionó con las variables hidrológicas (P > 0,05). Por individuo se midió el ancho de caparazón (AC) y peso (P); los machos se registraron en un intervalo de AC entre 12 y 85 mm y de 0,3 a 123,4 g, las hembras se recolectaron entre 9 y 92,8 mm AC y pesaron entre 0,7 a 152,6 g; 76,4 % de los especímenes correspondieron a tallas de 11 a 40 mm AC; se analizó el crecimiento relativo usando la relación biométrica AC vs. P, que para las jaibas jóvenes fue alométrica negativa independientemente del sexo; todos los individuos presentaron el telson diferenciado pero en etapas iniciales de desarrollo gonádico, la proporción sexual fue dominada por los machos; la ocurrencia de la talla de 11 a 20 mm AC durante el estudio indicó reclutamiento continuo al estuario.

ABSTRACT In this report are described abundance, size structure, and relative growth in Callinectes sapidus young stages from the Laguna El Llano blind estuary, Veracruz State (Mexico). Blue crabs were sampled in eight sampling sites since May 2013 to May 2014; four sites were located in un-vegetated, sandy bottom, and clear waters locations near to estuarine inlet, another four with fringe mangrove vegetation, muddy-bottom, and turbid waters. Were recorded pH, temperature, dissolved oxygen, turbidity, and salinity. A total of 276 organisms were collected (235 males and 41 females), young blue crabs were most numerous (91.3 %) in muddy-bottom, turbid waters sampling sites; the temporal abundance was not related statistically to hydrological variables (P >0.05). Were measured the Carapace Width (CW) and total weight (W) of each specimen, male CW ranked 12-85 mm and WW 0.3-123.4 g, while female CW was 9.0-92.8 mm and W 0.7-152.6 g; respect to total abundance, 76.4 % were 11-20 mm and 4160 mm CW size class specimens; the relative growth was analyzed by using CW vs. W biometric relationship, for young blue crabs were negative allometric growth, regardless of sex; all specimens showed morphologically differentiated telson but early gonadal development stages; males outnumbered the gender proportion; 11-20 mm CW blue crabs occurrence through study span indicated continuous recruitment processes in this estuary.

Abstract Spectral discrimination of mangrove leaves is the first step in classifying remotely sensed imagery of mangrove forests. The objective of this study was to analyze spectroscopic data on leaves from the upper and lower parts of mangrove canopies to discriminate species and physiognomic types. Leaf samples from the upper and lower parts of the canopies of 3 mangrove species (Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle) in 2 physiognomic types (basin and fringe) were collected during 2 seasons (dry and rainy). Probability distribution and first-derivative plots were generated for every wavelength (450-1,000 nm) detected in all samples. With the plots, optimal wavelengths were selected and subsequently verified with a canonical discriminant analysis. Results indicated that all species in basin mangrove forests showed a unique distinction between the upper and lower leaves during the dry season. By contrast, species in fringe mangrove forests did not show this difference during both seasons. Optimal wavelengths for species discrimination were located between 540-560 nm and 700-720 nm, which correspond to the green and red-edge wavebands, respectively. Future studies using remote sensing data with the aforementioned wavebands can be conducted to discriminate physiognomic mangrove forest types and to increase accuracy in the classification of mangroves at the canopy level on the Pacific coast of Mexico.

Resumen La discriminación foliar de mangles por medio de técnicas espectroscópicas es el primer paso para clasificar imágenes de sensores remotos de bosques de mangle. El objetivo de este estudio fue analizar datos espectroscópicos de hojas de la parte superior y la parte inferior del dosel arbóreo para poder discriminar especies y condiciones fisiognómicas en un bosque de mangle. Muestras de hojas de la parte superior y la parte inferior de los doseles de 3 especies de mangle (Avicennia germinans, Laguncularia racemosa y Rhizophora mangle) en 2 condiciones fisiognómicas (cuenca y borde) fueron recolectadas durante 2 temporadas (estiaje y lluvia). Gráficas de distribución de probabilidad y de primera derivada fueron generadas para cada una de las longitudes de onda (450-1,000 nm) de todas las muestras. Con base en las gráficas, las longitudes de onda óptimas fueron seleccionadas y, posteriormente, comprobadas con un análisis discriminante canónico. Los resultados indicaron que todas las especies de mangle tipo cuenca mostraron una separación única entre las hojas de la parte superior y la parte inferior del dosel durante la temporada de estiaje. Por el contrario, los mangles tipo borde no presentaron esta diferencia durante ambas temporadas. Las longitudes de onda óptimas para la discriminación de especies fueron localizadas entre 540-560 nm y 700-720 nm, correspondientes a las bandas verde y borde del rojo, respectivamente. Estudios posteriores con datos de sensores remotos que contengan dichas longitudes de onda pueden ser empleados para discriminar condiciones fisiognómicas en bosques de mangle e incrementar la precisión en clasificaciones de mangles a nivel de dosel en la costa mexicana del Pacífico.

Resumen Los manglares se distribuyen a lo largo de gradientes topográficos en zonas costeras, donde las variaciones en salinidad y períodos de inundación influyen en la composición y productividad primaria. En este estudio se evaluaron los atributos estructurales y producción de hojarasca de los manglares de la Laguna Mecoacán, Golfo de México. En seis sitios de monitoreo se determinó durante la segunda semana de julio 2014, la composición florística, el diámetro a la altura del pecho (DAP), altura, densidad del mangle adulto, juveniles, reclutas y plántulas. Además, se calcularon el área basal, índice de valor de importancia (IVI) y cobertura. Se tomaron muestras mensuales (noviembre 2014 a octubre 2015) de producción de hojarasca de las especies de mangle mediante trampas de captura, mientras que los parámetros físico-químicos de agua superficial, intersticial y subterránea fueron determinados mediante piezómetros. Los sitios de estudio en la Laguna Mecoacan se clasificaron en dos tipos fisonómicos: Borde (Boca, Aspoquero, Arrastradero y Pajaral) y cuenca (Cerros y Mojarrero). La densidad promedio del manglar fue de 2 870 árboles. ha-1. El área basal más alta se encontró en Pajaral (41.7 m-2. ha). Avicennia germinans (L.) Stearn presentó los valores más altos de IVI en todos los sitios. Se registró una cobertura media de 17.5 m2. Las especies mostraron zonación con los niveles de salinidad de agua intersticial; A. germinans con mayor densidad en áreas de alta salinidad (hipersalinas), mientras Laguncularia racemosa (L.) Gaertn y Rhizophora mangle L. en áreas de menor salinidad. La producción de hojarasca fue de 5.15 ton. ha-1. año-1, mostró una correlación positiva con la precipitación y alta correlación negativa con los niveles de salinidad y ORP intersticial y subterránea. Los resultados indican que la variabilidad en la composición, la estructura y la producción de hojarasca en la Laguna Mecoacán está determinada localmente por la capacidad de adaptación a las condiciones ambientales (precipitación, salinidad, potencial redox) de las especies presentes. Se recomienda establecer los sitios como parcelas permanentes de monitoreo y estimar la biomasa en pie y debajo del suelo para entender mejor la dinámica de nutrientes como una de las principales fuentes de energía in situ y exportado a zonas adyacentes.

Abstract Mangrove forests are distributed along the topographical gradients of coastal areas, where variations in salinity and flooding influence the composition and primary production of these forests. This study evaluated the structural attributes and production of leaf litter of mangrove species in Mecoacán Lagoon. We established six monitoring sites and studied the floristic composition, diameter at breast height (DBH), and density of adult, juvenile and recruited trees, as well as seedling density; additionally, the basal area, importance value index (IVI), and coverage were also calculated. Monthly samples (from November 2014 to October 2015) of the leaf litter production of different mangrove species, were collected using litter traps, and the physicalchemical parameters of surface, interstitial, and subterranean water were determined using piezometers. The study sites were classified into two physiognomic types: fringe (Boca, Aspoquero, Arrastradero, and Pajaral) and basin (Cerros and Mojarrero). The average density of mangrove trees was 2 870 trees. ha-1. The highest basal area was found in Pajaral (41.7 m2. ha-1). Avicennia germinans presented the highest IVI value in all sites. An average coverage of 17.5 m2 was recorded. The species were zoned with respect to interstitial salinity levels. A. germinans had a greater density in areas with high salinity (hypersaline) and Laguncularia racemosa and Rhizophora mangle in areas of lower salinity. The leaf litter production was 5.15 ton. ha-1. year-1 and showed a positive correlation with rainfall and a highly negative correlation with salinity level as well as with interstitial and subterranean oxidation redox potential (ORP). The results indicated that variability in the composition, structure, and production of leaf litter in Laguna Mecoacán is locally determined by the species capacity to adapt to environmental conditions (rainfall, salinity, redox potential). Several recommendations include the establishment of the sites evaluated in this study, as permanent monitoring areas and to estimate the above and belowground biomass, in order to understand the nutrient dynamics, as mangroves provide sources of energy both in situ and that may be exported to neighboring areas.

ResumenLa laguna costera de La Mancha, en el Golfo de México, tiene una boca que se cierra y abre estacionalmente, lo que ocasiona importantes fluctuaciones en los niveles de inundación y que la zona intermareal se exponga frecuentemente a una alta radiación solar, altas temperaturas y su consecuente desecación. Se llevó a cabo un experimento de campo de Noviembre-2000 a Septiembre-2001 para evaluar el efecto acumulado de la variación en el nivel de inundación sobre la colonización y supervivencia de los invertebrados intermareales sésiles sobre substratos artificiales en el bosque de manglar de borde. Un total de 72 tubos de PVC de 2 m de largo fueron recubiertos con cemento para semejar rizóforos (raíces aéreas) de Rhizophora mangle. Luego fueron encajados en el fango en cuatro estaciones de muestreo (18 por estación: 9 en sitio sombreado y 9 en sitio soleado), y fueron retirados en grupos de 6 de cada estación de muestreo (3 de cada sitio sombreado y 3 de cada sitio soleado), sin reemplazo, al término de cada época climática (nortes, seca y lluvias). Además, se monitoreó la condición abierta-cerrada de la boca estuarina y el nivel de inundación durante el período de 308 días que duró el experimento. Se registró la distribución temporal, espacial y vertical de la Riqueza específica (S) y de la abundancia de individuos vivos y muertos, y los datos fueron analizados mediante ANDEVA. Únicamente siete especies colonizaron los substratos, la mayoría de ellas se registraron todo el año y en todas las estaciones de muestreo. No se observó una sucesión estacional de las especies. Al final del experimento, se obtuvo una supervivencia del 20 % de los epibiontes. El poliqueto Ficopomatus miamiensis fue la especie más abundante pero presentó una supervivencia significativamente menor que las otras especies encontradas (0 - 14 %). Los epibiontes prefirieron establecerse en sitios sombreados que en sitios soleados sin importar la estación de muestreo ni la época climática. En conclusión, la colonización de los substratos artificiales fue exitosa pero la mayoría de los individuos murieron debido a la prolongada exposición y desecación después de que la boca estuarina fue abierta por los pescadores locales.Las maniobras de excavación de la barrera arenosa por los pescadores locales interrumpen los ciclos naturales de inundación de la laguna, lo cual puede tener consecuencias futuras sobre el desarrollo de las comunidades del manglar.

AbstractLa Mancha coastal lagoon, in the Gulf of Mexico, has an inlet that opens and closes seasonally, causing important fluctuations in flood-levels and exposing the intertidal zone to high solar radiation, high temperatures and desiccation. With the aim to examine the accumulated effect of variation in flood-levels on colonization and survival of sessile intertidal invertebrates on artificial substrates in a fringe mangrove forest, a field experiment was conducted from November-2000 to September-2001. A total of 72 PVC-stakes 2 m long were encased with cement to resemble rhizophores (prop roots) of Rhizophora mangle. They were then embedded in mud at four sampling stations (18 per station: 9 in a shaded site and 9 in a sunny site), and groups of 6 were collected from each sampling station (3 from each shaded site and 3 from each sunny site) without replacement at the end of each climatic period (Eastern winds, dry and rainy). The open-closed condition of the inlet and the flood-level were monitored during different days throughout the 308-day experiment period. Temporal, spatial and vertical distribution of Species richness (S) and abundance of living and dead individuals were registered, and the data was analyzed by ANOVA. Only seven species colonized the substrates, the majority of them were recorded throughout the year and in all sampling stations. There was no seasonal succession of species. At the end of the experiment, only 20 % of the epibionts had survived. The polychaete Ficopomatus miamiensis was the most abundant, but had significantly lower survival than the other species (0-14 %). Epibionts preferred to settle in shaded sites rather than sunny ones regardless of the sampling station and the climatic season. In conclusion, artificial substrate colonization was successful but the majority of epibionts died because of long exposure and desiccation after the inlet was opened by local fishermen. Manual digging of the sand-barrier by local fishermen, disrupts the natural flooding cycles of the lagoon, and could severely impact the future development of mangrove communities.

Resumo O objetivo deste estudo foi avaliar as características das florestas de um manguezal urbanizado, usando estrutura da vegetação e fatores abióticos para distinguir a heterogeneidade/qualidade do habitat. Foram selecionadas 16 áreas na Baía de Vitória, nas florestas de franja e de bacia. Os dados avaliados foram altura, DAP, área basal, densidade, dominância, água intersticial, litter mass, granulometria, matéria orgânica e influência antrópica. Os resultados indicam que o manguezal, por sofrer intensamente com diversos impactos antrópicos, apresenta bosques com diferentes graus de maturidade e heteregeneidade estrutural. Áreas mais distantes de impactos antrópicos diretos apresentam bosques com maior grau de desenvolvimento e qualidade ambiental em relação aos pontos mais próximos a pressões urbanas. Níveis intermediários de desenvolvimento também foram observados, indicando pulsos de alterações ambientais. Em escala local, as intervenções humanas provocaram alterações no desenvolvimento do bosque, amplificando a taxa de mortalidade e reduzindo o diâmetro e altura das florestas. As variáveis ambientais salinidade, matéria orgânica, litter mass, granulometria e os tensores antrópicos contribuíram para explicar os padrões estruturais da vegetação. Nossos dados sugerem que a análise da estrutura da vegetação e os fatores abióticos analisados são indicadores úteis para avaliar a qualidade do habitat, fornecendo uma base para gestão futura.

Abstract The objective of this study is to evaluate the characteristics of the forest in an urbanised mangrove using vegetation structure and abiotic conditions to distinguish habitat heterogeneity/quality. A total of 16 points in Vitória Bay were selected in the fringe and basin forests. The variables evaluated were height and diameter of the individual trees, basal area, density, dominance, interstitial water, litter mass, grain size, organic matter and anthropogenic influences. The results indicated that the mangrove area, due to suffering intensely from various anthropogenic effects, forests with varying degrees of maturity. Areas more distant from direct human effects had a higher degree of development and environmental quality relative to points closer to urban pressures. Intermediate development levels were also observed, which indicated pulses of environmental change. Human interventions caused alterations in the development of the forest which increased the mortality rate and reduced the diameter and height of the trees. The environmental variables of salinity, organic matter, litter mass, grain size and anthropogenic stressors contributed to the structural patterns. Our data suggest that an analysis of the vegetation structure and the abiotic factors are useful indicators to evaluate habitat quality, thus providing a basis for future management.

Resumen:Los manglares son asociaciones de plantas que se adaptan fácilmente a las condiciones salinas y los niveles fluctuantes de inundación. Estos ecosistemas suministran gran cantidad de bienes y servicios tales como el almacenamiento de carbono. Diferencias estructurales, de composición de especies y de características microambientales entre tipos fisiográficos implican diferencias en el almacenamiento de carbono en sus suelos. La presente investigación tuvo como objetivo identificar la variación de las especies de mangle a través de los cambios en las variables físico-bióticas de bosques de manglar de la bahía Cispatá, Colombia. Se realizaron mediciones de variables estructurales del bosque (D, H, densidad de individuos) y medición de variables físico-bióticas (nivel de inundación, cobertura de A. aureum, salinidad del agua intersticial. pH del suelo, % N, % limo, % arena, % COs, raíces y densidad aparente en el suelo) en 12 parcelas establecidas aleatoriamente. Con un CCA identificaron tres manglares: cuenca, borde en buen estado de conservación y borde con intervención antropogénica. El primero dominado por A. germinans y los otros por R. mangle. El manglar de cuenca se diferencia de los de borde en términos estructurales y en variables físico-bióticas, presentó los valores más altos de COs, salinidad, densidad aparente y pH. Aunque los dos manglares de borde presentan características físico-bióticas similares, la alteración antropogénica cambia fuertemente la estructura de uno de ellos. Se ha concluido que la distribución de las especies de manglar de la bahía responde a la variación espacial de las características ambientales. Sin embargo, la intervención antropogénica es una variable determinante en la estructura de los manglares lo cual afecta las estimaciones del papel de diferentes tipos de manglar como sumideros de carbono.

Abstract:Mangroves are plant associations that are easily adapted to saline conditions and fluctuating levels of flooding. This ecosystem provides a wide variety of goods and services as carbon storage. Structural differences, species composition and micro-environmental characteristics between physiographic types involve differences in carbon storage in their soils. This research aimed to identify the variation of mangrove species through changes in the physical-biotic variables of mangrove forest of Cispatá bay, Colombia. We measured structural variables of forest (D, H, density of individuals) as well as physico-biotic variables (flood level, A. aureum coverage, water interstitial salinity, soil pH, % N, % COs, roots and apparent density soil) in 12 plots established randomly. With a CCA it was identified three mangroves: basin, fringe in good condition and fringe with anthropogenic intervention. The first was dominated by A. germinans and the others by R. mangle. The basin mangrove differs from fringe in physical-biotic variables and structurally, it presented the highest values of COs, salinity, apparent density and pH. Although the two fringe mangrove exhibit similar physical-biotic variables, human disturbance may strongly change the structure of one of them. It was concluded that the distribution of mangrove species of bay responds to a spatial variation in environmental characteristics. However, anthropogenic intervention is a determining variable in the structure of mangroves which affects estimations of the role of different types of mangrove forests as carbon sinks.

The Gulf of Uraba is the largest estuary on the Caribbean coast of Colombia. The aim of this research was to analyse the oceanic, climatic and environmental variables that influence mangrove structure and composition in the gulf. Based on the availability of remote sensing, the study area was divided into western and eastern zones. The spatial pattern of environmental variables (water salinity, pH and percentage of organic matter, sand, silt and clay in the soils) and oceanic and climatic variables (winds, wave height and wave period) was analysed. The relationship of these variables with variables of vegetation structure (basal area, diameter at breast height, tree height, and abundance of seedlings of mangrove species in 1 m² subplots) was analysed in 27 plots of 500 m² containing fringe mangroves and 5 plots containing basin mangroves. Mangroves of the western zone showed a higher structural development and were dominated by Rhizophora mangle (red mangrove). This zone is supplied by fresh water and sediments, and the soils have a high content of organic matter and clay and a low degree of anthropogenic disturbance. The eastern zone was characterized by higher pore water salinity due to lower freshwater input from rivers. In this area there is a smaller impact of waves and winds, higher sedimentation rates, high anthropogenic disturbance and mangroves are dominated by Avicennia germinans (black mangrove). Although Laguncularia racemosa (white mangrove) did not show a particular spatial pattern, due to its tolerance to open canopy conditions it was commonly found in anthropogenically disturbed areas.

El Golfo de Urabá es el mayor estuario en la costa caribe de Colombia. El objetivo de esta investigación fue analizar las variables oceánicas, climáticas y ambientales que influyen en la estructura y composición de los manglares en el golfo. Según la disponibilidad de información de sensores remotos, el área de estudio se dividió en una zona occidental y otra oriental. Se analizó el patrón espacial de las variables ambientales (salinidad del agua, pH y porcentaje de materia orgánica, arena, limo y arcilla en los suelos) y las variables oceánicas y climáticas (vientos, altura y período del oleaje). Se analizó la relación de estas variables con las variables estructurales de la vegetación (área basal, diámetro a la altura del pecho, altura de los árboles y abundancia de plántulas de especies de manglar en sub-parcelas de 1 m²), en 27 parcelas de 500 m² que contienen manglares de borde y 5 parcelas que contienen manglares de cuenca. Los manglares de la zona occidental mostraron un desarrollo estructural superior y fueron dominados por Rhizophora mangle (mangle rojo). Esta zona recibe gran cantidad de agua dulce y sedimentos, y los suelos tienen alto contenido de materia orgánica y arcilla, y bajo grado de perturbación antrópica. La zona oriental se caracteriza por mayor salinidad del agua debido a una menor entrada de agua dulce de los ríos. En esta zona se presenta un menor impacto de oleaje y vientos, altas tasas de sedimentación, alta perturbación antrópica y los manglares están dominados por Avicennia germinans (mangle negro). Aunque Laguncularia racemosa (mangle blanco) no mostró un patrón espacial particular, debido a su tolerancia a las condiciones abiertas de dosel, se encuentra comúnmente en áreas con mayor intervención antrópica.

Resumen Se describe la composición florística del manglar y la distribución espacial de las principales especies de mangle y otras especies vegetales asociadas, presentes en el sector estuarino del Humedal Nacional Térraba-Sierpe, mediante el levantamiento de campo de 1 127 puntos y 77 parcelas de muestreo de 60x10m. Por otra parte, se explora la relación entre el tipo de sedimento subyacente y las especies de mangle establecidas sobre éste. Los resultados de composición, estructura y distribución de la vegetación del HNTS, muestran que el manglar exhibe un modelo o zonación, consistente en la variación desde la costa al continente y de las márgenes de los canales o esteros al interior de las llanuras de marea, de las distintas especies. Rhizophora racemosa y Pelliciera rhizophorae son las especies que muestran una mayor distribución espacial o distribución continua, con los mayores valores de abundancia (45.44% y el 39.92%, respectivamente), frecuencia (88.31% y 74.03%) y área de manglar (7 670.73ha y 5 824.94ha). Se confirmó la dependencia entre la presencia de especies de mangle y el tipo de sedimento del sustrato, de modo que las especies Avicennia spp. y L. racemosa tienden a distribuirse en los sustratos arenosos con mayor facilidad que las otras especies cuya distribución es más homogénea sobre los sustratos lodosos.

Abstract This research describes the floristic composition and spatial distribution of the main mangroves species and other associated flora present in the estuarine sector of Térraba-Sierpe National Wetland, Costa Rican Pacific. Field survey consists of 1 127 points and 77 sampling points of 60x10m. Results of composition, structure and distribution of mangrove in HNTS exhibits a pattern or species zonation. We found variation from the coast to mainland and from the fringe or estuaries to the interior tidal flats. The species Rhizophora racemosa and Pelliciera rhizophorae showed greater spatial and continuous distribution, with the highest values of abundance (45.44% and 39.92% respectively), frequency (88.31% and 74.03%) and mangrove area (7 670.73ha and 5 824.94ha). The mangrove fern, Acrostichum aureum, was the third most important species, meanwhile, Avicennia spp., Rhizophora mangle y Laguncularia racemosa showed a segregated distribution or a tendency to local conglomeration, Talipariti tiliaceum var. pernambucense, Mora oleifera y Conocarpus erectus were found in very localized areas and other species were considered companions with low contribution to the total coverage. The dependence was confirmed between the presence of mangrove species and sediment type substrate. The species Avicennia spp. and L. racemosa tend to be distributed in sandy substrates more easily than the other species whose distribution is more homogeneous on muddy substrates. Rev. Biol. Trop. 63 (Suppl. 1): 47-60. Epub 2015 April 01.

A serapilheira representa fonte de alimentos para diversos organismos que podem contribuir diretamente para a decomposição de matéria orgânica. A presença física desses detritos vegetais pode modificar áreas do ambiente e promover a formação de microhabitats, servindo de refúgio para diversos animais contra predadores e dessecação. O gastrópode Melampus coffeus (Linnaeus, 1758) (Ellobiidae) é comum em florestas de mangue na costa do Atlântico e se alimenta de folhas de mangue caídas. Nesse trabalho foi assumida a hipótese de que a distribuição espacial do Melampus coffeus é diretamente afetada pela deposição de serapilheira no manguezal. Objetivou-se avaliar a distribuição espacial desses gastrópodes em relação à serapilheira de mangue durante doze meses de coletas. A área de estudo foi estabelecida no médio estuário do rio Pacoti, Estado do Ceará, Brasil onde foram determinadas duas zonas de diferentes perfis topográficos. Amostras de Melampus coffeus e de serapilheira foram coletadas mensalmente. Os resultados indicaram que a presença de galhos na superfície do solo do manguezal favorece a ocupação do ambiente por indivíduos dessa espécie de molusco de menor tamanho, provavelmente porque indivíduos menores são mais suscetíveis ao ataque de predadores e à dessecação e a presença de galhos pode formar microhabitats mais seguros.

Leaf litter represents a food source to many organisms that may directly contribute to organic matter decomposition. In addition, the physical presence of these vegetal detritus contributes for the modification of some environmental areas and produce microhabitats that may act as a refuge against predators and desiccation for many animals. The pulmonate gastropod Melampus coffeus (Linnaeus, 1758) (Ellobiidae) is a very common specie in Atlantic Coast mangrove forests and feeds on fallen mangrove leaves. It was hypothesized that the spatial distribution of Melampus coffeus is directly affected by mangrove leaf litter biomass deposition. Thus, this research aimed at evaluating the spatial distribution of these gastropods in relation to the biomass of mangrove leaf litter through a twelve-month period. The study area was established in the middle estuary of Pacoti River, state of Ceará, Brazil where two adjacent zones with different topographic profiles were determined. Samples of Melampus coffeus and leaf litter were collected monthly, throughout a year, from the mangrove ground surface. The results indicated that the presence of twigs in mangrove litter favor the occupation by smaller individuals of M. coffeus, probably because smaller individuals are more susceptible to predator attacks and desiccation than larger ones, and twigs and branches may provide a safe microhabitat.

O manguezal do sistema estuarino de Santos, Brasil, ocupa uma área de 71 km2, consistindo de um complexo sistema de canais e rios, em ambiente predominantemente deposicional. O clima apresenta alta pluviosidade, sem déficit hídrico e com temperatura mínima de 18ºC. Foram mensuradas, contadas e identificadas 3.870 árvores de mangue em 20 seções aleatórias e medida a produção mensal de serapilheira. Os dados fitossociológicos (densidade, altura e área basal) foram medidos em parcelas a diferentes distâncias da linha da água. Três espécies de árvores foram identificadas: Rhizophora mangle, Avicennia schaueriana e Laguncularia racemosa. Os dados mostraram grande variabilidade entre bosques, mas sem zonação perpendicular à franja, em relação a todas as variáveis fitossociológicas, à distribuição das espécies arbóreas e à produção de serapilheira. Atribuiu-se este fenômeno ao baixo subsídio de energia devido ao regime de micromarés, à reduzida velocidade da água nas regiões internas do sistema estuarino, à homogeneidade do sedimento (silte), e, principalmente, à ausência de déficit hídrico na região. Todos estes fatores reduzem o gradiente ambiental da franja para a bacia. Alguns bosques apresentaram feições de imaturidade o que foi atribuído aos impactos antropogênicos de diversas naturezas, principalmente nos últimos 60 anos, que estariam obstando o pleno desenvolvimento do manguezal.

The mangrove forest of the estuarine system of Santos, Brazil, occupies 71 km2 - an area consisting of a complex system of canals and rivers forming a predominantly depositional environment. The climate provides high rainfall, with no water deficit and minimum temperatures above 18oC. In this environment, 3,870 mangrove trees, distributed on 20 random transects, were identified, counted and measured and the litterfall measured. The phytosociological data (density, height and basal area) were measured in parcels at different distances from the waterline. Three species of trees were identified: Rhizophora mangle, Avicennia schaueriana and Laguncularia racemosa. The data showed large variability between stands but with no zonation perpendicular to the fringe in relation to phytosociological descriptors, the distribution of the tree species and litterfall production. This phenomenon is attributed to the low energy subsidy occurring as a function of the microtidal regime, the reduced velocity of the water in the innermost regions of the estuarine system, the homogeneous sediment (silt) and mostly the absence of any water deficit in the region. All these factors reduce the environmental gradient from the fringe to the interior of the basin. Some stands also showed immature features which were attributed to the anthropogenic impacts of many kinds, mainly over the last 60 years, that have been preventing the mangroves from attaining their full development.

The purpose of the present study was to investigate the biodiversity, relative abundance and frequency of decapod crustaceans in the marine mangrove ecosystem at Gaibu Beach, Pernambuco State, Brazil. A total of eight samples were taken: four in the rainy season (August 2010) and four in the dry season (February 2011), during spring low tides and according to the phases of the moon. In all, 352 decapods were sampled. These specimens belonged to 17 species, 14 genera and 13 families. Pachygrapsus transversus (Gibbes, 1850), P. gracilis (Saussure, 1858), Panopeus americanus Saussure, 1857 and Uca (Leptuca) leptodactyla Rathbun, 1898 were very frequent. The three latter species occurred in all samples. The most abundant species was P. americanus. The Shannon-Wiener index (H') showed that, in general, the diversity level was medium for all samples. However, the sample taken at the time of the new moon during the rainy season was classified as highly diverse. These results contribute to the knowledge of the decapod fauna inhabiting mangroves associated with fringe reefs.

A hidrodinâmica, morfologia e sedimentologia do estuário do Taperaçu foram investigadas. Este é um entre vários estuários do litoral amazônico que integram a maior extensão contínua de manguezais do mundo, apresentando uma descarga de água doce muito reduzida, atípica para a região. Os resultados revelam grandes bancos arenosos que ocupam em grande parte a porção central do estuário. Areias muito finas e bem selecionadas de origem marinha prevalecem. Fases de enchente mais curtas, com velocidades de corrente substancialmente mais altas, são observadas na porção superior do estuário, como esperado para um estuário raso e dominado por fricção. Por outro lado, uma vazante mais intensa poderia ocorrer como resultado de grandes áreas de manguezais associadas e intenso preenchimento estuarino, sendo que ambas as condições são observadas no Taperaçu. Neste caso, a prevalência da enchente parece estar associada à ausência de uma descarga fluvial efetiva. Além disso, alguns canais de maré conectam o Taperaçu com seu vizinho estuário do Caeté, o que contribuiria para o domínio de enchente. Como um todo, os resultados demonstram uma complexa interação de aspectos de configuração (fricção, drenagem fluvial, conexões com estuários vizinhos, preenchimento e grandes áreas intermareais) na determinação dos padrões hidrodinâmicos, contribuindo para o entendimento dos estuários da região amazônica.

The hydrodynamics, morphology and sedimentology of the Taperaçu estuary were investigated. This is one of several estuaries located within the largest mangrove fringe in the world, bordering the Amazon region, subject to a macrotidal regime and regionally atypical negligible fresh water supply. The results reveal widespread sand banks that occupy the central portion of the estuarine cross-section. Well-sorted very fine sandy sediments of marine origin prevail. Shorter flood phases, with substantially higher current velocities, were observed in the upper sector of Taperaçu, as expected for a shallow, friction-dominated estuary. However, ebb domination can be expected for estuaries with large associated mangrove areas and substantial estuarine infilling, both of which situations occur on the Taperaçu. The tidal asymmetry favoring flood currents could be the result of the absence of an effective fluvial discharge. Furthermore, it was observed that the Taperaçu is connected by tidal creeks to the neighboring Caeté estuary, allowing a stronger flux during the flood and intensifying the higher flood currents. As a whole, the results have shown a complex interaction of morphological aspects (friction, fluvial drainage, connections with neighbor estuaries, infilling and large storage area) in determining hydrodynamic patterns, thus improving the understanding of Amazon estuaries.

Testemunhos de sondagem apresentam-se como importantes ferramentas para análise da dinâmica sucessional de bosques de mangue. A sucessão dos bosques de mangue, no litoral sul do Estado de São Paulo (Brasil), foi determinada com base em quatro testemunhos de sondagem: T1) banco de sedimento; T2) banco de gramínea Spartina alterniflora; T3) bosque de mangue em progradação, dominado por Laguncularia racemosa; e T4) bosque de mangue maduro, dominado por Avicennia schaueriana. Os testemunhos foram descritos macroscopicamente em função de cor, textura, estruturas sedimentares e componentes orgânicos. A base de todos os testemunhos apresentou padrão semelhante, sugerindo colonização similar por bosques de mangue , em toda sua extensão. Áreas em progradação apresentam banco de sedimento exposto, colonizado por S. alterniflora. Faixa de L. racemosa substitui a gramínea, com a progradação. À maior consolidação do sedimento, passam a dominar outras espécies típicas de mangue, como observado no bosque maduro, onde A. schaueriana alcança grande desenvolvimento estrutural. No testemunho coletado na área colonizada pelo bosque maduro dominado por A. shaueriana, há fragmentos de S. alterniflora próximo à base, confirmando o papel da gramínea como espécie pioneira. Os testemunhos analisados refletem a zonação e a sucessão dos bosques de mangue da região.

Sediment cores are an essential tool for the analysis of the dynamics of mangrove succession. Coring was used to correlate changes in depositional environments and lateral sedimentary facies with discrete stages of forest succession at the Cananéia-Iguape Coastal System in southeastern Brazil. A local level successional pattern was examined based on four core series T1) a sediment bank; T2) a smooth cordgrass Spartina alterniflora bank; T3) an active mangrove progradation fringe dominated by Laguncularia racemosa, and; T4) a mature mangrove forest dominated by Avicennia schaueriana. Cores were macroscopically described in terms of color, texture, sedimentary structure and organic components. The base of all cores exhibited a similar pattern suggesting common vertical progressive changes in depositional conditions and subsequent successional colonization pattern throughout the forest. The progradation zone is an exposed bank, colonized by S. alterniflora. L. racemosa, replaces S. alterniflora as progradation takes place. As the substrate consolidates A. schaueriana replaces L. racemosa and attains the greatest structural development in the mature forest. Cores collected within the A. schaueriana dominated stand contained S. alterniflora fragments near the base, confirming that a smooth cordgrass habitat characterized the establishment and early seral stages. Cores provide a reliable approach to describe local-level successional sequences in dynamic settings subject to drivers operating on multiple temporal and spatial scales where spatial heterogeneity can lead to multiple equilibria and where similar successional end-points may be reached through convergent paths.