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1.
PLoS One ; 15(1): e0227665, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31999717

RESUMEN

The restoration of mangroves has gained prominence in recent decades. Hydrological rehabilitation has been undertaken to connect impaired mangroves with the sea, lagoons or estuaries. Because mangrove hydrodynamics occurs on the surface and interstitial spaces in the sediment, we propose to determine the hydrological flow paths to restore the hydrological regimes of the impaired mangroves. The hydrological flow paths were determined through a micro basin analysis based on microtopographic data to generate a digital elevation model. Applying this methodological approach, the hydrology of an impaired area on a barrier island in the Gulf of Mexico was restored by excavating, desilting or clearing the channels on the identified hydrological flow paths. This area was compared to one in which impaired mangroves were reconnected to the marine lagoon but disregarding the flow paths. Data collected in both areas were evaluated by flood level analysis, using two methods: (i) a simple linear regression model (SLRM) and (ii) spectral analysis (SA), also known as dominant frequency analysis. The results suggest that restoration based on the hydrological flow paths was more effective than the direct opening to the nearest main water body without accounting for the microtopography. In both areas, soil salinity and sulfides decreased after hydrological reconnection. However, a greater efficiency in the investment of time and human resources was achieved when preferential flow paths were identified and taken into account. The methodological procedures described in this study are of universal application to other mangrove restoration programs.


Asunto(s)
Conservación de los Recursos Naturales/métodos , Humedales , Cambio Climático/estadística & datos numéricos , Conservación de los Recursos Naturales/estadística & datos numéricos , Conservación de los Recursos Hídricos/métodos , Conservación de los Recursos Hídricos/estadística & datos numéricos , Monitoreo del Ambiente/estadística & datos numéricos , Estuarios , Inundaciones/prevención & control , Inundaciones/estadística & datos numéricos , Golfo de México , Hidrodinámica , Islas , Modelos Lineales , México , Modelos Teóricos , Salinidad , Suelo
2.
Sci Total Environ ; 653: 1253-1261, 2019 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-30759565

RESUMEN

The Gulf of Mexico blue carbon habitats (mangroves, seagrass, and salt marshes) form an important North American blue carbon hot spot. These habitats cover 2,161,446 ha and grow profusely in estuaries that occupy 38,000 km2 to store substantial sedimentary organic carbon of 480.48 Tg C. New investigations around GoM for Mexican mangroves, Louisiana salt marshes and seagrasses motivated our integration of buried organic carbon to elucidate a new estimate of GoM blue carbon stocks. Factors creating this include: large GoM watersheds enriching carbon slowly flowing through shallow estuarine habitats with long residence times; fewer SE Mexican hurricanes allowing enhanced carbon storage; mangrove carbon productivity enhanced by warm southern basin winter temperatures; large Preservation reserves amongst high anthropogenic development. The dominant total GoM mangrove blue carbon stock 196.88 Tg from total mangrove extent 650,482 ha is highlighted from new Mexican data. Mexican mangrove organic carbon stock is 112.74 Tg (1st sediment meter) plus USA 84.14 Tg. Mexican mangroves vary greatly in storage, total carbon depositional depths and in sediment age (to 3500 y). We report Mexican mangrove's conservative storage fraction for the normally-compared top meter, whereas the full storage depth estimates ranging above 366.78 Tg (high productivity in very deep sediment along the central Veracruz/Tabasco coast) are not reflected in our reported estimates. Seagrasses stock of 184.1 Tg C organic is derived from 972,327 ha areal extent (in 1st meter). The Louisiana marshes form the heart of GoM salt marsh carbon storage 99.5 Tg (in 1st meter), followed by lesser stocks in Florida, Texas, finally Mexico derived from salt marsh extent totaling 650,482 ha. Constraints on the partial estuarine fluxes given for this new data are discussed as well as widespread anthropogenic destruction of the GoM blue carbon. A new North American comparison of our GoM blue carbon stocks versus Atlantic coastal blue carbon stock estimates is presented.


Asunto(s)
Carbono/análisis , Monitoreo del Ambiente , Sedimentos Geológicos/química , Ecosistema , Estuarios , Golfo de México
3.
Sci Total Environ ; 605-606: 626-636, 2017 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-28672251

RESUMEN

Seagrasses comprise a substantive North American and Caribbean Sea blue carbon sink. Yet fine-scale estimates of seagrass carbon stocks, fluxes from anthropogenic disturbances, and potential gains in sedimentary carbon from seagrass restoration are lacking for most of the Western Hemisphere. To begin to fill this knowledge gap in the subtropics and tropics, we quantified organic carbon (Corg) stocks, losses, and gains from restorations at 8 previously-disturbed seagrass sites around the Gulf of Mexico (GoM) (n=128 cores). Mean natural seagrass Corg stocks were 25.7±6.7MgCorgha-1 around the GoM, while mean Corg stocks at adjacent barren sites that had previously hosted seagrass were 17.8MgCorgha-1. Restored seagrass beds contained a mean of 38.7±13.1MgCorgha-1. Mean Corg losses differed by anthropogenic impact type, but averaged 20.98±7.14MgCorgha-1. Corg gains from seagrass restoration averaged 20.96±8.59Mgha-1. These results, when combined with the similarity between natural and restored Corg content, highlight the potential of seagrass restoration for mitigating seagrass Corg losses from prior impact events. Our GoM basin-wide estimates of natural Corg totaled ~36.4Tg for the 947,327ha for the USA-GoM. Including Mexico, the total basin contained an estimated 37.2-37.5Tg Corg. Regional US-GoM losses totaled 21.69Tg Corg. Corg losses differed significantly among anthropogenic impacts. Yet, seagrass restoration appears to be an important climate change mitigation strategy that could be implemented elsewhere throughout the tropics and subtropics.


Asunto(s)
Ciclo del Carbono , Carbono/análisis , Ecosistema , Restauración y Remediación Ambiental , Hydrocharitaceae/crecimiento & desarrollo , Región del Caribe , Cambio Climático , Sedimentos Geológicos/química , Golfo de México
4.
Rev. biol. trop ; Rev. biol. trop;65(2): 745-761, Apr.-Jun. 2017. tab, ilus
Artículo en Español | LILACS-Express | LILACS | ID: biblio-897578

RESUMEN

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.

5.
Rev. biol. trop ; Rev. biol. trop;65(2): 701-712, Apr.-Jun. 2017. tab, ilus
Artículo en Inglés | LILACS | ID: biblio-897574

RESUMEN

AbstractIn community ecology, the knowledge of abiotic factors, that determine intraspecific variability in ecophysiological and functional traits, is important for addressing major questions, such as plant community assembly and ecosystem functioning. Mangroves have several mechanisms of resistance to salinity and most species exhibit some xeromorphic features in order to conserve water. Leaf area and stomatal density play an important role in maintaining water balance, and gas exchange is regulated by their aperture and density, two traits that vary intraspecifically in response to environmental conditions, such as water stress and salinity. In this study, we evaluated the effects of salinity on stomatal density, leaf area and plant size in R. mangle and we tested for associations among the three variables, across three sites along a natural salinity gradient in the XelHá Park, Quintana Roo, Mexico. We hypothesized that high salinity sites would produce smaller plants, with smaller leaves, and fewer stomata. Three sampling sites with different environmental conditions were chosen and salinities were monitored monthly. A total of 542 plants were tagged and tree heights and diameters were measured for each individual within each of the three sampling sites. Three leaves from 20 trees from each site were measured to determine leaf area. Stomatal densities were determined in each leaf using nail polish casts, examining ten 1 mm squares per leaf under an optical microscope. A principal component analysis was used to assess association between tree height, leaf area, and stomatal density for each plot. The salinity gradient was reflected in plant size, producing smaller plants at the higher salinity site. The largest leaves were found at the low salinity site (51.2 ± 24.99 cm2). Leaf length was not correlated to plant size (LL vs. tree height: r= 0.02, P= 0.8205; LL vs. trunk diameter: r= 0.03, P= 0.7336), so we concluded that leaf length is an environmentally plastic trait of red mangroves that may vary as a function of environmental conditions, such as hydric stress caused by elevated salinity. The larger leaves from the low salinity site had lower densities of stomata (65.0 stomata.mm2 SD= 12.3), and increasing salinities did not decrease stomatal density (intermediate salinity site: 73.4 stomata.mm2 SD= 13.5; high salinity site: 74.8 stomata.mm2 SD= 17.3). Our results confirm that stomatal density is inversely related to leaf area (r= -0.29, P < 0.001), especially leaf width (r= -0.31, P < 0.001), and that salinity may increase stomatal density by causing reduction of leaf size.


ResumenLos manglares tienen varios mecanismos de resistencia salina y la mayoría de las especies presentan algunas características xeromórficas con el fin de conservar el agua. El tamaño de la hoja y la densidad de los estomas desempeñan un papel importante en el mantenimiento del equilibrio hídrico. El intercambio de gases puede mediarse mediante la regulación de la apertura de los estomas, así como el número de estomas sobre la epidermis, dos características que pueden variar intraespecíficamente en función las condiciones ambientales, tales como el estrés hídrico. Rhizophora mangle es una de las especies de mayor importancia en América del Norte y Sur, y de África occidental. El objetivo de este trabajo fue evaluar los efectos de la salinidad sobre la densidad de los estomas, el tamaño de la hoja y el tamaño de las plantas de Rhizophora mangle y determinar si existe una relación entre las tres variables, comparándose tres ambientes diferentes a lo largo de un gradiente natural de salinidad en Xel-Há, Quintana Roo, México. La hipótesis fue que los ambientes de alta salinidad producirían plantas más pequeñas, con hojas más pequeñas y menos estomas. Se seleccionaron tres sitios de estudio con condiciones ambientales diferentes y se midió la salinidad cada mes. Un total de 542 plantas fueron etiquetadas en los tres sitios, y se midió su altura y diámetro del tronco. Se recolectaron tres hojas de 20 árboles en cada uno de los sitios, y se obtuvo el área de cada hoja. La densidad estomática se midió mediante la técnica de microrelieve con barniz de uñas, observando diez 1 mm cuadrados bajo un microscopio óptico. Se utilizó un análisis de componentes principales para determinar la asociación entre altura de árbol, área de hoja y densidad estomática. El gradiente de salinidad se vio reflejado en el tamaño de las plantas, produciendo plantas más pequeñas en el sitio de alta salinidad. El largo de las hojas no se correlacionó con el tamaño de las plantas, por lo cual se concluyó que esta variable tiene plasticidad ambiental particular. Las hojas más grandes fueron encontradas en el sitio de baja salinidad y tuvieron densidades estomáticas menores. No se pudo observar que la densidad de estomas disminuyera con las altas salinidades. Estos resultados confirman que la densidad estomática es inversamente relacionada con el tamaño de la hoja, especialmente el ancho, y que la densidad estomática incrementa con la salinidad debido a la reducción del tamaño de hoja.

6.
Ann Bot ; 115(5): 833-40, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25681823

RESUMEN

BACKGROUND AND AIMS: Rhizophora species of mangroves have a conspicuous system of stilt-like roots (rhizophores) that grow from the main stem and resemble flying buttresses. As such, the development of rhizophores can be predicted to be important for the effective transmission of dynamic loads from the top of the tree to the ground, especially where the substrate is unstable, as is often the case in the habitats where Rhizophora species typically grow. This study tests the hypothesis that rhizophore architecture in R. mangle co-varies with their proximity to the main stem, and with stem size and crown position. METHODS: The allometry and wood mechanical properties of R. mangle (red mangrove) trees growing in a mangrove basin forest within a coastal lagoon in Mexico were compared with those of coexisting, non-buttressed mangrove trees of Avicennia germinans. The anatomy of rhizophores was related to mechanical stress due to crown orientation (static load) and to prevailing winds (dynamic load) at the study site. KEY RESULTS: Rhizophores buttressed between 10 and 33 % of tree height. There were significant and direct scaling relationships between the number, height and length of rhizophores vs. basal area, tree height and crown area. Wood mechanical resistance was significantly higher in the buttressed R. mangle (modulus of elasticity, MOE = 18·1 ± 2 GPa) than in A. germinans (MOE = 12·1 ± 0·5 GPa). Slenderness ratios (total height/stem diameter) were higher in R. mangle, but there were no interspecies differences in critical buckling height. When in proximity to the main stem, rhizophores had a lower length/height ratio, higher eccentricity and higher xylem/bark and pith proportions. However, there were no directional trends with regard to prevailing winds or tree leaning. CONCLUSIONS: In comparison with A. germinans, a tree species with wide girth and flare at the base, R. mangle supports a thinner stem of higher mechanical resistance that is stabilized by rhizophores resembling flying buttresses. This provides a unique strategy to increase tree slenderness and height in the typically unstable substrate on which the trees grow, at a site that is subject to frequent storms.


Asunto(s)
Avicennia/fisiología , Raíces de Plantas/fisiología , Rhizophoraceae/fisiología , Animales , Avicennia/anatomía & histología , Fenómenos Biomecánicos , Ecología , Ecosistema , México , Raíces de Plantas/anatomía & histología , Tallos de la Planta/anatomía & histología , Tallos de la Planta/fisiología , Rhizophoraceae/anatomía & histología , Árboles , Humedales , Viento , Madera/anatomía & histología , Madera/fisiología , Xilema/anatomía & histología , Xilema/fisiología
7.
Rev. biol. trop ; Rev. biol. trop;62(4): 1309-1330, oct.-dic. 2014. graf, mapas, tab
Artículo en Español | LILACS | ID: lil-753692

RESUMEN

La Mancha lagoon is connected to the Gulf of Mexico through an estuarine ephemeral inlet, a sand bar, which opens during the rainy season and closes during the late fall and the winter storm season. As the lagoon fills up with the permanent stream flow into its Southern part, the water level increases and the sand bar opens up, releasing huge volumes of water into the ocean and leaving the previously flooded intertidal zone exposed to drying. In this study, we described the spatial and temporal variations of structure and composition of the community living on the surface of red mangrove prop roots, related to the hydrodynamic of the estuarine inlet. Four red mangrove prop roots were collected every three months, over an annual period, at ten sampling stations. Water temperature, salinity, dissolved oxygen, water depth and transparency were also measured at each sampling event. To describe the identity, abundance, biomass, and specific richness of epibiont coverage on the prop roots, measurements were taken at 10cm intervals (herein called “horizons”). A total of 59 632 specimens and a total biomass of 172g/cm2 were registered, and a maximum of eleven horizons presented at least one species of epibionts. Two species of polychaetes, 12 of mollusks and 14 of crustaceans were identified, with Mytilopsis leucophaeata as the most abundant, Ficopomatus miamiensis as the most common and Crassostrea rhizophorae with the highest contribution in biomass. Sampling effort was assessed using species accumulation curves, resulting that the efficiency was, in general, greater than 90% of the richness predicted by asymptotic models. The hydrodynamics of the estuarine inlet had a great influence on the environmental conditions of the lagoon and on the spatial and temporal variation of the epibiont community: (a) when the inlet is open, there is a North-South gradient in environmental parameters (b) when the inlet is closed and the water level increases, the epibionts especially the pioneer species F. miamiensis, occupied the highest horizons of prop roots, and (c) the abundance, biomass and richness of epibionts increased towards the deeper and less saline Southern part of the lagoon, as well as on permanently submerged horizons, and during the seasonal closure of the inlet. Variations in depth are determined by the hydrodynamic behavior of the estuarine inlet, suggesting that these factors are major biodiversity drivers of the epibiont community at La Mancha. Rev. Biol. Trop. 62 (4): 1309-1330. Epub 2014 December 01.


La laguna de La Mancha está conectada al Golfo de México a través de una boca estuarina efímera, una barra arenosa, la cual se abre durante la época de lluvias y se cierra durante el otoño y la temporada de vientos invernales. Cuando la laguna se llena con la entrada de agua proveniente de un arroyo permanente, ubicado en la parte sur, el nivel del agua se incrementa y la barra arenosa se abre, descargando grandes volúmenes de agua hacia el océano y dejando expuesta a la desecación la zona intermareal previamente inundada. En este estudio, se describen las variaciones espacio-temporales de la estructura y composición de la comunidad de epibiontes que vive en la superficie de las raíces del mangle rojo,y su relación con la dinámica hidrológica de la boca estuarina. Se recolectaron cuatro raíces trimestralmente, durante un año, en diez estaciones de muestreo. También se midió la temperatura del agua, salinidad, oxígeno disuelto, profundidad y transparencia en cada muestreo. Se determinó la abundancia, la biomasa y la riqueza específica, a lo largo de las raíces en segmentos verticales de 10cm llamados horizontes. Se registraron un total de 59 632 especímenes y una biomasa total de 172g/cm2, y un máximo de once horizontes presentaron al menos una especie de epibionte. Se identificaron dos especies de poliquetos, 12 de moluscos y 14 de crustáceos, siendo Mytilopsis leucophaeata la más abundante, Ficopomatus miamiensis la más común y Crassostrea rhizophorae la de mayor contribución a la biomasa. Se evaluó la eficiencia del muestreo mediante curvas de acumulación de especies, resultando que la eficiencia fue, en general, >90% de la riqueza estimada por modelos asintóticos. La hidrodinámica de la boca estuarina tuvo gran influencia en las condiciones ambientales de la laguna y en las variaciones espacio-temporales de la comunidad de epibiontes: (a) cuando la boca estuarina está cerrada son más claros los gradientes ambientales norte-sur, (b) cuando la boca estuarina se cierra y el nivel de inundación se incrementa, los epibiontes, especialmente la especie pionera F. miamiensis, ocupan los horizontes más altos de las raíces, (c) la abundancia, biomasa y riqueza específica de los epibiontes se incrementó hacia las partes más profundas del sur de la laguna, así como en los horizontes permanentemente inundados, y durante el cierre estacional de la boca estuarina. Las variaciones en la profundidad dependen de la dinámica de la boca estuarina, sugiriendo que estos factores son los principales parámetros que estructuran a la comunidad de epibiontes de La Mancha.


Asunto(s)
Animales , Ecosistema , Invertebrados/clasificación , Rhizophoraceae/clasificación , Biomasa , México , Densidad de Población , Dinámica Poblacional , Estaciones del Año , Análisis Espacio-Temporal
8.
Front Plant Sci ; 5: 503, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25309570

RESUMEN

Over the last several decades, the distribution of the black mangrove Avicennia germinans in the Gulf of Mexico has expanded, in part because it can survive the occasional freeze events and high soil salinities characteristic of the area. Vessel architecture may influence mangrove chilling and salinity tolerance. We surveyed populations of A. germinans throughout the Gulf to determine if vessel architecture was linked to field environmental conditions. We measured vessel density, hydraulically weighted vessel diameter, potential conductance capacity, and maximum tensile fracture stress. At each sampling site we recorded mangrove canopy height and soil salinity, and determined average minimum winter temperature from archived weather records. At a subset of sites, we measured carbon fixation rates using a LI-COR 6400XT Portable Photosynthesis System. Populations of A. germinans from cooler areas (Texas and Louisiana) had narrower vessels, likely reducing the risk of freeze-induced embolisms but also decreasing water conductance capacity. Vessels were also narrower in regions with high soil salinity, including Texas, USA and tidal flats in Veracruz, Mexico. Vessel density did not consistently vary with temperature or soil salinity. In abiotically stressful areas, A. germinans had a safe hydraulic architecture with narrower vessels that may increase local survival. This safe architecture appears to come at a substantial physiological cost in terms of reduction in conductance capacity and carbon fixation potential, likely contributing to lower canopy heights. The current distribution of A. germinans in the Gulf is influenced by the complex interplay between temperature, salinity, and vessel architecture. Given the plasticity of A. germinans vessel characters, it is likely that this mangrove species will be able to adapt to a wide range of potential future environmental conditions, and continue its expansion in the Gulf of Mexico in response to near-term climate change.

9.
Rev Biol Trop ; 62(4): 1309-30, 2014 Dec.
Artículo en Español | MEDLINE | ID: mdl-25720169

RESUMEN

La Mancha lagoon is connected to the Gulf of Mexico through an estuarine ephemeral inlet, a sand bar, which opens during the rainy season and closes during the late fall and the winter storm season. As the lagoon fills up with the permanent stream flow into its Southern part, the water level increases and the sand bar opens up, releasing huge volumes of water into the ocean and leaving the previously flooded intertidal zone exposed to drying. In this study, we described the spatial and temporal variations of structure and composition of the community living on the surface of red mangrove prop roots, related to the hydrodynamic of the estuarine inlet. Four red mangrove prop roots were collected every three months, over an annual period, at ten sampling stations. Water temperature, salinity, dissolved oxygen, water depth and transparency were also measured at each sampling event. To describe the identity, abundance, biomass, and specific richness of epibiont coverage on the prop roots, measurements were taken at 10 cm intervals (herein called "horizons"). A total of 59,632 specimens and a total biomass of 172 g/cm2 were registered, and a maximum of eleven horizons presented at least one" species of epibionts. Two species of polychaetes, 12 of mollusks and 14 of crustaceans were identified, with Mytilopsis leucophaeata as the most abundant, Ficopomatus miamiensis as the most common and Crassostrea rhizophorae with the highest contribution in biomass. Sampling effort was assessed using species accumulation curves, resulting that the efficiency was, in general, greater than 90% of the richness predicted by asymptotic models. The hydrodynamics of the estuarine inlet had a great influence on the environmental conditions of the lagoon and on the spatial and temporal variation of the epibiont community: (a) when the inlet is open, there is a North-South gradient in environmental parameters (b) when the inlet is closed and the water level increases, the epibionts especially the pioneer species F. miamiensis, occupied the highest horizons of prop roots, and (c) the abundance, biomass and richness of epibionts increased towards the deeper and less saline Southern part of the lagoon, as well as on permanently submerged horizons, and during the seasonal closure of the inlet. Variations in depth are determined by the hydrodynamic behavior of the estuarine-inlet, suggesting that these factors are major biodiversity drivers of the epibiont community at La Mancha.


Asunto(s)
Ecosistema , Invertebrados/clasificación , Rhizophoraceae/clasificación , Animales , Biomasa , México , Densidad de Población , Dinámica Poblacional , Estaciones del Año , Análisis Espacio-Temporal
10.
Environ Entomol ; 39(4): 1165-9, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22127167

RESUMEN

At two temperate pasturelands in northern Mexico, we explored possible competition for food and space under pats during the simultaneous nesting periods of the univoltine species Dichotomius colonicus (Say), Phanaeus quadridens (Say), and Copris sierrensis Matthews. To simulate unlimited resources, 50 5-kg cow dung pats were placed at regular distance intervals in each pastureland. After building trenches around the pats, the number and depth of each nest, as well as larval development status, were documented once for a period of 1-8 mo. Analyses of variance and association tests were used to make a between-site comparison of dung pat occupation, nests occupied per species, nests per dung pat, and nest depth below each pat. The proportion of pats occupied by each species differed significantly between sites. C. sierrensis colonizing most pats at one site and D. colonicus at the other. There were no differences between sites in the frequency of pats occupied by more than one species. The association test and Ochiai index showed that each species colonized dung pats independently. The results suggest that pat occupation depended on their location by beetles and the relative abundance of each species. The species tended to dig nests at different depths, possibly reducing interspecific competition for space. It can therefore be concluded that, when food resources seem to be unlimited, they are shared following a "lottery dynamic" model if there is spatial differentiation among species.


Asunto(s)
Escarabajos , Conducta Competitiva , Ecosistema , Comportamiento de Nidificación , Animales , Conducta Alimentaria , Femenino , Larva , Masculino , México , Pupa , Reproducción
11.
Interciencia ; Interciencia;31(3): 211-219, mar. 2006. tab
Artículo en Español | LILACS | ID: lil-449246

RESUMEN

Los manglares que rodean la laguna de La Mancha en Veracruz, México, en condiciones de adecuada conservación, se caracterizan por la complejidad físico-geográfica de sus paisajes. Este trabajo profundiza en la estructura y composición de los geocomplejos en ese territorio. El empleo de los principios estructuro-genético e histórico-evolutivo permitió el levantamiento, clasificación y cartografía de los paisajes de manglares a escala detallada (1: 25000). Se lograron diferenciar 28 unidades inferiores, 6 intermedias y 5 de orden superior. Los resultados sugieren que el enfoque físico-geográfico complejo puede ser de gran utilidad para el inventario, caracterización y cartografía de manglares a escala detallada, brindando información sobre el tipo genético del relieve, composición litológica, periodicidad de inundación de las superficies, cobertura vegetal y suelos, lo cual es de inestimable valor para el ordenamiento ecológico y la preservación de estos ecosistemas


Asunto(s)
Flora Acuática , Humedad , Laguna Costera , Humedales , Ecosistema Tropical , México
12.
Interciencia ; Interciencia;29(3): 138-144, mar. 2004. tab, graf
Artículo en Español | LILACS | ID: lil-399854

RESUMEN

El Archipiélago de Camagüey, en la costa norte de la zona centro-occidental de Cuba, se destaca por la presencia de elevados valores biológicos en paisajes bien conservados. Este trabajo explora la relación entre heterogeneidad de los paisajes físico-geográficos y la riqueza de flora vascular en este territorio. La riqueza y diversidad del paisaje resultaron variables explicativas de la riqueza de especies de flora. El modelo estadístico que se obtuvo explica más del 82 por ciento de la relación. Los resultados sugieren que la riqueza de flora puede ser predicha por los valores de heterogeneidad geoecológica. En este sentido, se sigiere explorar la probable exsitencia de zonas de elevada biodiversidad en áreas de difícil acceso o poco conocidas, mediante análisis de heterogeneidad de paisajes físico-geográfico


Asunto(s)
Ecología , Flora , Cuba
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