Cambios de la hidrología en los manglares se traducen en gradientes bien definidos de degradación que principalmente inducen una disminución de su estructura. Un buen estimador de la estructura de un bosque es el Índice de Complejidad,... more
Cambios de la hidrología en los manglares se traducen en gradientes bien definidos de degradación que principalmente inducen una disminución de su estructura. Un buen estimador de la estructura de un bosque es el Índice de Complejidad, que relaciona densidad, área basal, altura y el número de especies presentes en 0.1 ha, siendo éstos susceptibles a ser modificados por factores estresantes. Desde 1998, un manglar neotropical localizado dentro del sitio Ramsar No. 1602 quedo fragmentado por la construcción de tres estructuras sólidas en todo lo ancho del bosque modificando la hidrología. Esta acción con el tiempo ocasiono la degradación, reflejando tres escenarios de perturbación en el bosque, secciones aparentemente no degradadas, semidegradadas y sitios con mortandad completa. El presente trabajo, basado en dos indicadores ecológicos busco encontrar cambios en el comportamiento de la estructura arbórea y la regeneración que evidenciaran el proceso de degradación. Se estableció un sitio de referencia y se realizaron cuatro transectos más abarcando el ancho del manglar y todos los escenarios de degradación. Se realizaron cuadrados de 10 x 10 m a cada 25 m, tomado los indicadores para procesar el Índice de Complejidad y un Estimador de Regeneración. El sitio de referencia presento el mejor valor del estimador de regeneración y el segundo mejor en estructura arbórea con relación a los fragmentos del bosque. Al comparar por la condición de degradación, el sitio de referencia y el área que aparentemente no se encuentra degradada tuvieron valores cercanos, no así la condición semidegradada que presento valores muy por debajo, principalmente atribuidos a su baja densidad y altura de sus individuos. En comparación con el sitio de referencia, las áreas aparentemente no degradadas de los fragmentos del bosque tienen buen desarrollo estructural y regeneración, por lo que es factible una rehabilitación para solventar el estrés causado y comenzar su recuperación, no así para el área de mortandad total, que requiere la intervención activa para comenzar un lento proceso que lleve a su integración a las otras áreas.
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Xenobalanus globicipitis is a commensal barnacle located on cetacean fin edges. The commensal-host interaction between Xenobalanus globicipitis and the bottlenose dolphin (Tursiops truncatus) has been poorly studied in Mexico. The main... more
Xenobalanus globicipitis is a commensal barnacle located on cetacean fin edges. The commensal-host interaction between Xenobalanus globicipitis and the bottlenose dolphin (Tursiops truncatus) has been poorly studied in Mexico. The main objective was to estimate the relative barnacle prevalence and abundance in bottlenose dolphins in three areas and seasons of the Gulf of Mexico. Tamiahua zone showed the higher prevalence (42.4%) and relative abundance (0.60 barnacles/individual/hr-1)compared to Tuxpan and Nautla zones. Whereas, in dry season there were higher prevalence (55.6%) and relative abundance (0.53 barnacles/individual/hr-1)than rainy and winter storm seasons. Therefore, zones and seasons of the Gulf of Mexico influence the barnacle-dolphin interactions.
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Mangrove forests have declined worldwide and understanding the key drivers of regeneration at different perturbation levels can help manage and preserve these critical ecosystems. For example, the Ramsar site # 1602, located at the... more
Mangrove forests have declined worldwide and understanding the key drivers of regeneration at different perturbation levels can help manage and preserve these critical ecosystems. For example, the Ramsar site # 1602, located at the Tampamachoco lagoon, Veracruz, México, consists of a dense forest of medium-sized trees composed of three mangrove species. Due to several human activities, including the construction of a power plant around the 1990s, an area of approximately 2.3 km2 has suffered differential levels of perturbation: complete mortality, partial tree loss (divided into two sections: main and isolated patch), and apparently undisturbed sites. The number and size of trees, from seedlings to adults, were measured using transects and quadrats. With a matrix of the abundance of trees by size categories and species, an ordination (nMDS) showed three distinct groups corresponding to the degree of perturbation. Projection matrices based on the size structure of Avicennia germinans...
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Abstract: The West Indian manatee (Trichechus manatus) is distributed from the Atlantic coast of the United States to the center of Brazil along the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. The species’ current distribution is... more
Abstract: The West Indian manatee (Trichechus manatus) is distributed from the Atlantic coast of the United States to the center of Brazil along the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. The species’ current distribution is more fragmented than in the past, and manatee populations are generally less abundant than they were during the last century. In Mexico, there is no specific information about the size of the manatee populations. Hence, the objective of this study was to estimate the density and abundance of manatees in the Alvarado Lagoon System (ALS) in Veracruz using distance sampling. In total, 959 systematic line transects were surveyed using a small boat. These surveys covered 90% of the ALS. Manatee density and abundance for the entire ALS was estimated at 0.23 animals/km2 (CV 34.48%) and 121 manatees (CV 34.48%), respectively. These are the first density and abundance estimates for this lagoon system and for the State of Veracruz. The extremely low number of manatees supports the urgent implementation of effective conserva¬tion measures for the species to prevent extinction of this species in Veracruz. Key Words: West Indian manatee, Trichechus manatus manatus, abundance, density, Veracruz, conservation, coastal management, Gulf of Mexico, Sirenia
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Conocarpus erectus L. is rarely reported specie in Mexico and its role in the mangrove ecosystem is not understood. In order to describe its ecological role within the community, it is necessary to learn about its attributes as species.... more
Conocarpus erectus L. is rarely reported specie in Mexico and its role in the mangrove ecosystem is not understood. In order to describe its ecological role within the community, it is necessary to learn about its attributes as species. The main objective of this study was to determine ...
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Introducción: Los manglares están en declive en el mundo, conocer su estructura y regeneración en diferentes niveles de alteración puede ayudar a comprender la dinámica poblacional ante situaciones de estrés. Objetivo: La meta principal... more
Introducción: Los manglares están en declive en el mundo, conocer su estructura y regeneración en diferentes niveles de alteración puede ayudar a comprender la dinámica poblacional ante situaciones de estrés. Objetivo: La meta principal del estudio fue analizar la estructura comunitaria y estimar la trayectoria de las poblaciones de Avicenia germinans en diferentes sitios de manglar que presentan tres niveles de alteración. Métodos: Ocho transectos de aproximadamente 500 m de largo y colocados de manera perpendicular a la laguna de Tampamachoco, Veracruz, interceptaron tres niveles de alteración en los sitios estudiados del bosque de manglar. En cada transecto, cuadrantes de 10 x 10 m, 5 x 5 m, y 1 x 1 m sirvieron para contar todos los árboles de mangle por especie y estadio de madurez en 2017 y 2018. Resultados: La especie más abundante fue: A. germinans seguida de Rhizophora mangle y Laguncularia racemosa. Con base en su abundancia, se encontraron diferencias significativas según ...
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Abstract: The West Indian manatee (Trichechus manatus) is distributed from the Atlantic coast of the United States to the center of Brazil along the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. The species’ current distribution is... more
Abstract: The West Indian manatee (Trichechus manatus) is distributed from the Atlantic coast of the United States to the center of Brazil along the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. The species’ current distribution is more fragmented than in the past, and manatee populations are generally less abundant than they were during the last century. In Mexico, there is no specific information about the size of the manatee populations. Hence, the objective of this study was to estimate the density and abundance of manatees in the Alvarado Lagoon System (ALS) in Veracruz using distance sampling. In total, 959 systematic line transects were surveyed using a small boat. These surveys covered 90% of the ALS. Manatee density and abundance for the entire ALS was estimated at 0.23 animals/km2 (CV 34.48%) and 121 manatees (CV 34.48%), respectively. These are the first density and abundance estimates for this lagoon system and for the State of Veracruz. The extremely low number of manatees supports the urgent implementation of effective conserva¬tion measures for the species to prevent extinction of this species in Veracruz.
Key Words: West Indian manatee, Trichechus manatus manatus, abundance, density, Veracruz, conservation, coastal management, Gulf of Mexico, Sirenia
Key Words: West Indian manatee, Trichechus manatus manatus, abundance, density, Veracruz, conservation, coastal management, Gulf of Mexico, Sirenia
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This study contributes to the knowledge of macroalgae associated to four habitats at Tuxpan Reef, Veracruz, México. Wecarried out, 20 sampling in four habitats: grass beds, coral rubble, coralline rock-coral and coralline rock-sea urchin,... more
This study contributes to the knowledge of macroalgae associated to four habitats at Tuxpan Reef, Veracruz, México. Wecarried out, 20 sampling in four habitats: grass beds, coral rubble, coralline rock-coral and coralline rock-sea urchin, fromApril to June 2005. We ...
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The biology and ecology of Conocarpus erectus var. sericeus Grisebash are poorly known, this has led to its undervaluationas a member of the mangrove ecosystem. It was important to investigate its seed germination in order to advance... more
The biology and ecology of Conocarpus
erectus var. sericeus Grisebash are poorly
known, this has led to its undervaluationas a member of the mangrove ecosystem.
It was important to investigate its seed germination
in order to advance the knowledge
of this species. This study was carried out
in two phases: Field, identifi cation of trees
with seeds and trees with infructescenses;
and Laboratory, cleaning of seeds, and
assay to get: sample weight, purity analyzes,
and a germination test with different
treatments. The germination test lasted fi ve
weeks, and 2 500 pure seeds were used, that
were divided into groups of 500 seeds for
each of the fi ve utilized treatments; two to
break the exogenous latency: physical and
chemical abrasion with HCl; another two
groups for endogenous latency with H2O2
and refrigeration; with a control group as
well. The experimental design was applied
in a randomized complete blocks, because
the source of variation for germinated
seeds per week was considered important
for the study. Repeated Measures ANOVA
was used since the seed number variation
was considered important for this study.
The results show that the sample weighted
23.22 g, with a 78% of purity. The ANDEVA
test established that there is no signifi cant
difference between the treatments, but that
there is a signifi cant difference among the
number of germinated seeds per week, been
the second week the different one. Also,
there is a signifi cant effect by the interaction
of Time*Treatment with H2O2 during week
one and refrigeration on week two.
Key words: mangrove buttonwood, germination,
treatments.
erectus var. sericeus Grisebash are poorly
known, this has led to its undervaluationas a member of the mangrove ecosystem.
It was important to investigate its seed germination
in order to advance the knowledge
of this species. This study was carried out
in two phases: Field, identifi cation of trees
with seeds and trees with infructescenses;
and Laboratory, cleaning of seeds, and
assay to get: sample weight, purity analyzes,
and a germination test with different
treatments. The germination test lasted fi ve
weeks, and 2 500 pure seeds were used, that
were divided into groups of 500 seeds for
each of the fi ve utilized treatments; two to
break the exogenous latency: physical and
chemical abrasion with HCl; another two
groups for endogenous latency with H2O2
and refrigeration; with a control group as
well. The experimental design was applied
in a randomized complete blocks, because
the source of variation for germinated
seeds per week was considered important
for the study. Repeated Measures ANOVA
was used since the seed number variation
was considered important for this study.
The results show that the sample weighted
23.22 g, with a 78% of purity. The ANDEVA
test established that there is no signifi cant
difference between the treatments, but that
there is a signifi cant difference among the
number of germinated seeds per week, been
the second week the different one. Also,
there is a signifi cant effect by the interaction
of Time*Treatment with H2O2 during week
one and refrigeration on week two.
Key words: mangrove buttonwood, germination,
treatments.
Conocarpus erectus L. is a rarely reported specie in Mexico, its role in the mangrove ecosystem is not understood. In order to know its interactions and role within the community, it is necessary to learn about its attributes as species.... more
Conocarpus erectus L. is a rarely reported specie in Mexico, its role in the mangrove ecosystem is not understood. In order to know its interactions and role within the community, it is necessary to learn about its attributes as species. The main objective of this study was to determine the distribution patterns, structural attributes, and functions of this species in the Ramsar Site No. 1602 “Manglares y Humedales de Tuxpan”. Sampling took place from September 2005 to December 2006. For each site (Laguna de Tampamachoco y Estero de Jácome) a description of the distribution pattern of the mangrove species, the structural attributes (Height, Diameter at Breast Height, and Basal Area), and the productivity attributes (fallen leaves, flower, and miscellaneous) for Conocarpus erectus L. was made. A One Way Analysis of Variance was made to determine if there were significant differences among the structural parameters, the productivity. The distribution pattern shows this species far away from the mangrove forest, in areas with no influence from the tides, and at the edge of the Jacome estuary and the Tampamachoco lagoon. We found 190 individuals with an average height of 3.1m, a 8.2 cm (DBH), and a basal area of 0.598 m2/ha. The productivity was composed mainly by leaves (14.82 g/ m2/month). There were significant differences among sampling sites for height, DBH, basal area and productivity. This shows the heterogeneity of this species at the Ramsar site.