Propágulos deMangrove species propagules represent a particular survival and dispersal strategy. Unfortunately, some reports have stated that Rhizophora mangle propagules are frequently attacked by Coleoptera and Lepidoptera before and after their dispersion period. The beetle species Coccotrypes rhizophorae is an obligate parasite that can cause mortality in propagules and seedlings of R. mangle, and may modify the structure of its populations. Because of the importance on this mangrove species, survival and increasing human impacts in the area, this study evaluated the presence of propagules with C. rhizophorae boring evidence in the Tumilco mangrove, in Veracruz State, Mexico. For this, three sampling areas were established: 1) mangrove core of R. mangle, 2) most impacted edge of an unpaved road with R. mangle and A. germinans, and 3) edge with Typha latifolia and R. mangle; in each area, three 25x25 m random plots were analyzed. The number of bored propagules per site was recorded every 15 days over a sampling period of one year (n= 567) from January to December 2012. We also observed the damaged part of the propagule (basal, central, apical) and the number of live and dead bored propagules per season, and compared results for different seasons in the area: rainy, cold northerly fronts or "norte" and dry. Insects were identified by an expert. Our results showed that a higher number of bored propagules was observed during the dry season, mainly in zones 2 and 3. Survival of bored propagules was higher when the perforation occurred in the basal part of the plant, and during the dry and norte seasons. Study zone 2 in particular presented a higher number of live propagules when the damage occurred in the basal part of the propagule. In all three zones, mortality was higher when the damage was apical. Zones 1 and 3 presented higher propagule survival during the dry season, while survival in zone 2 was higher during the rainy and norte seasons. The number of propagules decreased with rising flooding levels. The results showed that C. rhizophorae has a wide distribution in the Tumilco mangrove, but the mortality of R. mangle propagules is influenced by the part of the propagule that suffers damage, as well as by the season of the year and the characteristics of the area in which the infestation occurs. Futher studies are required to evaluate the impact of propagule mortality on the population structure of R. mangle. Rev. Biol. Trop. 65 (3): 1120-1128. Epub 2017 September 01.
Concentración dePollution by heavy metals in marine ecosystems in the Gulf of Mexico is one of the hardest conservation issues to solve. Sharks as top predators are bioindicators of the marine ecosystem health, since they tend to bioaccumulate and biomagnify contaminants; they also represent a food source for local consumption. Thus, the objective of this study was to study the possible presence of heavy metals and a metalloid in livers of Carcharhinus limbatus. For this, a total of 19 shark livers were taken from animals captured nearby Tamihua, Veracruz, Mexico from December 2007 to April 2008. 12 out of the 19 captured sharks were males, one was an adult female, three were juvenile males, and three juvenile females. Four heavy metals (Hg, Pb, Cd, and Cr) and one metaloid (As) were analyzed in shark livers using an atomic absorption spectrophotometry with flame and hydride generator. Our results showed that the maximum concentrations found were: Hg=0.69mg/kg, Cd=0.43mg/kg, As=27.37mg/kg, Cr=0.70mg/kg. The minimum concentrations found were: As=14.91mg/kg, Cr=0.35mg/kg. The Pb could not be determined because the samples did not have the spectrophotometer minimum detectable amount (0.1mg/kg). None of the 19 samples analyzed showed above the permissible limits established by Mexican and American laws. There was a correlation between shark size and Cr and As concentration (Pearson test). The concentration of Cr and As was observed to be higher in bigger animals. There was not a significant difference in heavy metals concentration between juveniles and adults; however, there was a difference between males and females. A higher Cr concentration was found in females when compared to males. None of the samples exceed the maximum limit established by the laws of Mexico and the United States of America. Much longer studies are needed with C. limbatus and other species caught in the region, in order to determine the degree of contaminants exposure in aquatic ecosystems and to identify potential health risks to consumers. Rev. Biol. Trop. 61 (2): 821-828. Epub 2013 June 01.
Los humedales costeros e interiores de México son un hábitat importante para las aves. La pérdida y degradación de los humedales, ha sido una de las principales amenazas para la avifauna. En la actualidad se desconoce el número de individuos de las especies de aves que se encuentran en la mayoría de los humedales. Considerando lo anterior, el objetivo de este trabajo fue determinar la diversidad y abundancia de aves en un humedal del norte de Veracruz, el manglar de Tumilco, en Tuxpan. Se utilizó el método de muestreo a distancia y la observación directa para determinar la diversidad y abundancia del total de aves presentes en el manglar. En total se realizaron 63 muestreos con 386 horas efectivas de esfuerzo, llevándose a cabo 274 transectos lineales con longitud de 1 km, en toda el área de estudio. Se registraron 56 especies de aves pertenecientes a 23 familias. Se observaron seis especies que se encuentran dentro de la NOM-059-SEMARNAT-2010, de las cuales la especie más abundante fue Anas platyrhynchos diazi y la menos representativa Falco peregrinus. La abundancia total estimada de las especies observadas para toda el área de estudio fue de 5945 individuos (intervalo de confianza al 95% = 5035; C.V. = 7.25%) y una densidad de 0.53 organismos/ha (intervalo de confianza al 95% = 0.49; C.V. = 7.25%). Este estudio demuestra que el manglar de Tumilco es fundamental para la conservación de la avifauna de Veracruz.
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