Efecto de la ganadería y la variación estacional sobre la composición florística y la biomasa vegetal en los humedales de la costa centro oeste del Golfo de México

Background and Aims: Wetlands are highly productive ecosystems, which provide many environmental services. However, they are one of the most threatened due to human activities such as agriculture and livestock. Mexico has lost 62% of its wetlands and specifically those of the central coast of the Gulf of Mexico are being affected due to livestock pressure. There are very few studies about the subject, so in this paper we analyze the effect of livestock and seasonality on floristic composition, above ground biomass (AB) and below ground biomass (BB) of the Alvarado lagoon, Veracruz, Mexico.Methods: We selected two working locations, and in each locality chose two sampling sites. In each site, we placed eight 1 m² plots of four different locations (half were fenced to keep out livestock). For an entire year we obtained species richness and diversity, and data on vegetation cover, as well as AB and BB. With the data obtained, we calculated the Relative Importance Value (RIV) by species and the relative replacement rate of species.Key results: Total richness resulted in 29 species. A disturbance gradient was observed, with the best conserved sites in Río Blanco. In most sites, species richness was significantly higher in rainfall and species with high RIV were typical wetland species, although there were dominant grasses in both climatic seasons. BB was significantly higher in one location of Rio Blanco, and AB in one location of Rio Blanco and in one from Rio Limon. During the rainy season, AB was higher in half of the sites.Conclusions: We conclude that freshwater wetlands can retain their ecological functions in the presence of livestock as long as the impact is low. Even if there is cattle grazing with a controlled management, it can promote diversity of native wetland species and limit the growth of invasive grasses.Antecedentes y Objetivos: Los humedales son ecosistemas altamente productivos que aportan diversos servicios ecosistémicos; sin embargo, también son de los más amenazados debido a actividades humanas como la agricultura y ganadería. México ha perdido 62% de sus humedales y específicamente los de la costa central del Golfo de México se están viendo afectados debido a la actividad ganadera. Existen pocos trabajos acerca del tema; por tanto, en esta investigación se analizó el efecto de la ganadería y la estacionalidad sobre la composición florística, biomasa aérea (BA) y biomasa subterránea (BS) de humedales herbáceos de la laguna de Alvarado, Veracruz, México.Métodos: Se seleccionaron dos localidades de trabajo y en cada una se eligieron dos sitios de muestreo. En cada sitio se colocaron ocho parcelas de 1 m² (la mitad fueron cercadas para evitar al ganado). Durante un año se obtuvieron datos de riqueza y diversidad de especies, cobertura vegetal, BA y BS. Con estos datos se calculó el valor de importancia relativa (VIR) por especie e índice de reemplazo de especies.Resultados clave: Se registraron 29 especies y se observó un gradiente de perturbación, resultando las localidades de Río Blanco las más conservadas. En general la riqueza fue significativamente mayor en lluvias y las especies con mayor VIR fueron las propias de humedales, aunque hubo gramíneas dominantes en ambas temporadas. La BS fue significativamente mayor en Río Blanco (sitio 1), y la BA en Río Blanco 1 y Río Limón 1. En lluvias la BA fue mayor en la mitad de los sitios.Conclusiones: Con los resultados de este trabajo se observa que los humedales herbáceos de agua dulce pueden conservar sus funciones ecológicas en presencia de la ganadería siempre y cuando sea de bajo impacto. Inclusive, si ésta se practica de manera controlada, puede favorecer la diversidad de especies nativas del humedal y limitar el crecimiento de pastos invasores

Hacia la restauración con Annona glabra (Annonaceae) de una selva inundable: establecimiento y crecimiento de plántulas, y cambio en la vegetación acompañante

Background and Aims: Currently, freshwater swamps are deteriorating and their cover is decreasing, mainly due to deforestation for livestock and the introduction of exotic grasses. The objectives of this study were to evaluate the survival and the growth of Annona glabra seedlings, monitor changes in the accompanying vegetation, and estimate the cost of our experimental ecological restoration treatments in a freshwater swamp transformed into a flooded pasture and invaded by the exotic grass Echinochloa pyramidalis.Methods: The study was carried out on a floodplain surrounding a mangrove on the coast of central Veracruz, Mexico. It consisted of sowing four A. glabra seedlings in experimental quadrats exposed to different restoration techniques. Fifteen experimental restoration treatments were tested consisting of five restoration techniques (no modification, covering with plastic, planting Pontederia sagittata, soil removal, and raising the soil level), and three pretreatments applied to the seedlings planted (nursery seedlings with and without fertilizer, seedlings collected from the wetlands) in a random block design.Key results: Low seedling survival was recorded (30.7%), but this was higher for the seedlings from freshwater wetlands (41.1%). The highest percent survival was recorded where the soil was raised, followed by the soil removal technique. Regarding the vegetation, 40 species were recorded and the highest species richness was observed where the soil had been raised and where it had been removed. The Relative Importance Value was highest for Echinochloa pyramidalis, Mimosa pigra, and Annona glabra. The pretreatment of obtaining seedlings directly from the wetland was the cheapest one.Conclusions: Action is required to increase reforestation success. For future restoration projects, we recommend that the soil in the transplanting area be raised and covered with plastic before planting, to increase the probability of seedling survival and reduce grass cover. Moreover, seedlings collected from a swamp fragment should be used for reforestation.Antecedentes y Objetivos: Actualmente existe deterioro y disminución de selvas inundables debido a la deforestación para ganadería e introducción de pastos exóticos. Los objetivos del presente estudio fueron evaluar el porcentaje de supervivencia de plántulas de Annona glabra, el cambio en la vegetación acompañante, y estimar los costos de los tratamientos experimentales de restauración ecológica de una selva inundable de A. glabra transformada en pastizal e invadida por el pasto exótico Echinochloa pyramidalis. Métodos: El estudio se realizó en un pastizal inundable en la costa central de Veracruz, México. Consistió en sembrar cuatro plántulas de A. glabra en cuadros experimentales expuestos a distintas técnicas de restauración. Se probaron 15 tratamientos experimentales que consistieron en cinco técnicas de restauración (sin modificación, cubierta plástica, plantación de Pontederia sagittata, remoción de suelo, y elevación del suelo) y tres pretratamientos aplicados a las plántulas sembradas (plántulas de vivero con y sin fertilizante, plántulas de selva) en un diseño de bloques al azar.Resultados clave: Se registró baja supervivencia de plántulas (30.7%), siendo mayor en plántulas de selva (41.1%). El mayor porcentaje de supervivencia se registró con la técnica de elevación del suelo, seguido de la de remoción. Se registraron 40 especies en la vegetación; la mayor riqueza específica se observó en las técnicas de elevación del nivel del suelo y remoción. Las especies con mayor Valor de Importancia Relativa fueron Echinochloa pyramidalis, Mimosa pigra y Annona glabra. El pretratamiento en el cual se obtuvieron las plántulas directamente de la selva fue el más económico.Conclusiones: Se requieren acciones para incrementar el éxito de la reforestación. Para futuros proyectos de restauración, recomendamos la elevación del suelo en áreas de transplante y cubierta de plástico previo a la plantación, para incrementar la probabilidad de supervivencia, y reducir la cobertura del pasto; además de la reforestación con plántulas colectadas de un fragmento de selva

Potencial de invasión de Phragmites australis en comunidades dominadas por especies nativas ante disturbios por fuego en condiciones controladas

Background. Wetlands are heterogeneous and dynamic ecosystems, very susceptible to invasions or local extinctions by the effects of invasive or over-dominant plant species. Resistance to invasion in wetlands that suffer disturbances such as fires has not been thoroughly studied. When Phragmites australis (common read) is present, its interaction with disturbance factors has led to local extinction of many native species. In a previous study, it was determined that harvesting is an effective control method for this species. But removal of aerial parts of this species generates many fragments that might propagate the species. Goals. Evaluate under controlled conditions the invasive potential of fragments of Phragmites australis in plant communities dominated by native plant species that are subjected to frequent human-made disturbances, such as fire, under controlled conditions. Methods. We carried out an experiment that consisted of two assays in 36 mesocosms with canopies of Schoenoplectus americanus. Results. Phragmites australis was practically not able to establish itself after the loss of the S. americanus canopy following fires, because the canopy of this last species recovered rapidly. Survival and growth were slightly higher in mesocosms with low disturbance (27.7% and 55.9 cm in the first assay, and 9.4%, and 60.6 cm in the second assay), when compared with controls (8.5% 35.3 cm, and 7.4% and 86.7 cm), because in control units the canopy of S. americanus was a permanent barrier to the development of P. australis. Height differences among burned and control mesocosms after the first fire event were significant (p =0.002) but not after two consecutive years of burning (p =0.085), because the few plants that survived in control units reached considerable height. Conclusions. The risk of establishment of the fragments of Phragmites australis that are generated during harvesting is low even after major disturbances of native vegetation cover.Antecedentes. Los humedales son ecosistemas heterogéneos y dinámicos muy susceptibles a sufrir invasiones o extinciones locales por especies invasoras o sobredominantes. La resistencia a la invasión de los humedales ante factores de disturbio como el fuego ha sido poco estudiada. Cuando Phragmites australis (carrizo) se encuentra presente, su interacción con factores de disturbio ha llevado a la extinción local de muchas especies nativas. En un estudio anterior se determinó que la cosecha de esta especie es una estrategia efectiva de control. Sin embargo, la remoción de las partes aéreas genera múltiples fragmentos a partir de los cuales se podría propagar la especie. Objetivos. Evaluar, ante disturbios ocasionados por el fuego, en condiciones controladas, el potencial de invasión de fragmentos de Phragmites australis en comunidades dominadas por especies nativas. Métodos. El experimento se efectuó bajo dos quemas en 36 mesocosmos con doseles de Schoenoplectus americanus y P. australis. Resultados. Los resultados establecieron que las plantas de Phragmites australis no lograron desarrollarse después de las quemas del dosel de S. americanus, debido a la rápida recuperación del dosel de esta segunda especie. Se registró mayor supervivencia y crecimiento en los mesocosmos con bajo disturbio (27.7% y 55.9 cm en el primer ensayo; 9.4% y 60.6 cm en el segundo ensayo) en comparación con los controles (8.5%, 35.3 cm y 7.4% y 86.7 cm), ya que el dosel de S. americanus se mantuvo como una barrera al desarrollo de P. australis en los controles. Las diferencias en la altura fueron significativas después del primer evento de fuego entre los mesocosmos quemados y los de control (p =0.002), pero después de dos años de quema no lo fueron (p =0.085), debido a que las pocas plantas que sobrevivieron en los mesocosmos control alcanzaron alturas considerables. Conclusiones. Los fragmentos de P. australis representan bajo riesgo para sitios con dosel de S. americanus después de un año de registrar disturbios como el fuego

Use of trees in Jamapa, traditions in a deforested area

Los árboles han jugado un papel fundamental en el desarrollo de las civilizaciones, tanto como recursos de aprovisionamiento como por otros servicios ecosistémicos. Sin embargo hay una fuerte perturbación de los bosques tropicales que ha disminuido la cantidad y diversidad de los árboles. Una de las causas principales de esta situación es el cambio de uso del suelo, sobre todo para actividades ganaderas, que en el estado de Veracruz, México, ocupan alrededor de 3.7 millones de hectáreas (50.6% de su territorio). El objetivo de este trabajo fue investigar el conocimiento que los ganaderos tienen sobre las especies arbóreas, sus usos, su importancia cultural y los cambios que han sucedido a lo largo del tiempo. Se mencionaron 68 especies de árboles y se hizo una clasificación de 22 tipos de usos. Se calculó el índice de importancia cultural de cada especie y se describieron los cambios más importantes en el estilo de vida de las comunidades de estudio. Se encontró que hay un conocimiento amplio sobre los árboles pero se está perdiendo rápidamente. Los árboles se usan no solo para obtener beneficios en la ganadería sino para satisfacer otras necesidades de la vida cotidiana. La cantidad y la diversidad de especies arbóreas refleja el estilo de vida de las comunidades junto con sus influencias y cambios en el tiempo. Las decisiones de los ganaderos configuran el paisaje y por lo tanto se recomienda aumentar la cantidad de árboles en los potreros, su conservación y su uso para mantener los servicios ecosistémicos que proveen.Trees have played an important role in the development of civilizations, both for provisioning of resources and for other environmental services. However, there is a strong decrease in the quantity and diversity of tropical forests trees due to land use changes. One of the main causes of this situation is the livestock activity, which in the state of Veracruz, Mexico, occupies a surface of about 3.7 million hectares (representing 50.6% of its territory). The objective of this study was to research into cattle ranchers’ knowledge of arboreal species, their uses, their cultural importance and the changes that have taken place over time. Sixty eight species of trees were mentioned and their uses were classified in 22 types of uses. The cultural importance index was calculated for each species and the most important changes in the communities’ lifestyle were described. The results showed that ranchers have a wide knowledge about trees but it is rapidly disappearing. Trees are used not only to get benefits for the livestock activity but also to satisfy other needs of daily life. The quantity and diversity of arboreal species reflect the lifestyle, influences and changes over time within the communities. The decisions of ranchers configure the landscape, and therefore the recommendation is to increase the amount of trees, their conservation and uses to maintain the environmental services they provide.Esta investigación fue realizada con fondos de OIMT del proyecto RED-PD 045/11 Rev.2 (M) y la beca doctoral otorgada por Conacyt a la primera autora (no. 208529)

Artificial Modifications of the Coast In Response to the \u3ci\u3eDeepwater Horizon\u3c/i\u3e Oil Spill: Quick Solutions or Long-Term Liabilities?

The Deepwater Horizon oil spill threatened many coastal ecosystems in the Gulf of Mexico during the spring and summer of 2010. Mitigation strategies included the construction of barrier sand berms, the restriction or blocking of inlets, and the diversion of freshwater from rivers to the coastal marshes and into the ocean, in order to flush away the oil, on the premise that these measures could reduce the quantity of oil reaching sensitive coastal environments such as wetlands or estuaries. These projects result in changes to the ecosystems that they were intended to protect. Long-term effects include alterations of the hydrological and ecological characteristics of estuaries, changes in sediment transport along the coastal barrier islands, the loss of sand resources, and adverse impacts to benthic and pelagic organisms. Although there are no easy solutions for minimizing the impacts of the Deepwater Horizon disaster on coastal ecosystems, we recommend that federal, state, and local agencies return to the strategic use of long-term restoration plans for this region

Coastal risk mitigation by green infrastructure in Latin America

This paper aims to highlight the prevailing experiences of Latin America and to clarify what ‘green infrastructure’ entails in addition to describing seven case studies from a range of coastal ecosystems (wetlands, coastal dunes, beaches and coral reefs) at scales varying from local to regional. The case studies are categorised according to their degree of naturalness (nature-based, engineered ecosystems, soft engineering, ecologically enhanced hard infrastructure and de-engineering). Generally, the implementation of green infrastructure projects aims to increase resilience, enhance the provision of ecosystem services, recover biodiversity, reduce the negative effects of hard infrastructure and implement corrective measures. The greatest benefits of these projects relate to the creation of multi-functional spaces, which often combine the above advantages with improved opportunities for recreation and/or economic activities. It is hoped that this paper will disseminate the experience in green infrastructure among academics and practitioners and stimulate wider adoption of green infrastructure projects and good practices

Divulgação do risco de crédito antes e após a crise financeira de 2008: o caso das empresas do setor bancário do PSI-20

Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Contabilidade e FinançasA crise financeira de 2008 evidenciou a necessidade da qualidade da informação divulgada sobre os riscos, assim como a falta de transparência nos relatórios das empresas. Para colmatar este deficit de transparência, as empresas do setor bancário estão sujeitas ao cumprimento das normas emitidas pela Comissão de Mercado e Valores Mobiliários (CMVM), pelo International Accounting Standards Board (IASB), bem como da legislação que resulta dos Acordos de Basileia. O presente estudo procura analisar as práticas de divulgação de informação sobre o risco de crédito antes e “após” a mais recente crise financeira em quatro empresas do setor bancário português cotadas na Euronext Lisboa e incluídas no Portuguese Stock Index (PSI) 20. Para o efeito foi utilizado o método qualitativo e o método da análise de conteúdo. Os dados foram extraídos dos relatórios e contas de 2006 e 2012 das empresas da amostra. Verifica-se que, em geral, as empresas cumpriam os requisitos previstos no normativo contabilístico, regras, regulamentos e outra legislação aplicável.); e que a informação mais divulgada referia-se aos objetivos e políticas de gestão do risco de crédito. Verifica-se, ainda, que a informação divulgada em 2012 melhorou significativamente face a 2006; e houve um grande envolvimento por parte dos órgãos reguladores na adequação das normas e legislações às novas realidades proporcionadas pelo sistema financeiro.Abstract:The financial crisis of 2008 has highlighted the need for the quality of information disclosed about the risks, as well as the lack of transparency in corporate reporting. To overcome this deficit of transparency, companies in the banking sector are subject to compliance with the rules issued by the Comissão de Mercado e Valores Mobiliários (CMVM), by the International Accounting Standards Board (IASB), as well as by the legislation that has derived from the Basel Accords. The present study seeks to analyse the information disclosure practices on credit risk before and "after" the latest financial crisis in four Portuguese banking companies listed on Euronext Lisbon and included in the Portuguese Stock Index (PSI) 20. For this purpose we used the qualitative method and the method of content analysis. The data were extracted from the 2006 and 2012 Annual Accounts of the companies included in the sample. It turns out that, in general, the companies met the requirements set out in accounting standards, rules, regulations, and other applicable law.); and that the information disclosed was referring to the goals and policies of credit risk management. It, also, turns out that the information disclosed in 2012 has significantly improved compared to 2006; and there was a great involvement on the part of regulators on the appropriateness of standards and legislation to the new realities offered by the financial system

Flora en playas y dunas costeras de México

Background and Aims: The first updated floristic checklist, supported with herbarium specimens, is presented for beaches and coastal sand dunes of Mexico.Methods: The analysis is based on the revision of 14 national and foreign herbaria. A 2 × 2 km grid was placed over a map of the coastal sand dunes of Mexico to reference the herbarium records, corresponding to the 2180 sites and 12,419 examples of plants documented. Indices of diversity, similarity, taxonomic diversity, and redundancy were calculated.Key results: The flora of the beaches and coastal sand dunes of Mexico consists of 153 families, 897 genera, and 2075 species of vascular plants. These represent 9.5% of the vascular flora of Mexico. The herbaria with high indices of redundancy (IR≥0.7) are the herbarium of the Universidad Nacional Autónoma de México (IR=0.9), the Centro de Investigación Científica de Yucatán (CICY, IR=0.8), the Centro de Investigaciones Biológicas del Noroeste (HCIB), the Instituto de Ecología, A.C. (XAL) and the Natural Museum in San Diego (SD), each with an IR of 0.7. Five floristic regions are clearly recognized, which correspond to the seas of Mexico. The North Pacific has the highest taxonomic diversity and the South Pacific has the least. The Gulf of California, Gulf of Mexico and the Caribbean Sea have very similar taxonomic diversity. The species with the most recorded occurrences are Trianthema portulacastrum (165), Croton punctatus (107), Echites umbellatus (106) and Ipomoea pes-caprae (90). Considering the ecotonal nature of the ecosystem, most dune plants are shared with neighboring vegetation (forests, scrubs, wetlands, such as marshes or mangrove swamps).Conclusions: This first checklist of the flora of beaches and coastal dunes is the baseline for multiple future studies: floristic, biogeographic, and ecological. Moreover, this list will be important if used in environmental assessments and coastal zone plans.Antecedentes y Objetivos: Se presenta el primer listado florístico de las playas y dunas costeras de México, actualizado y respaldado por ejemplares de herbario.Métodos: Se revisaron 14 herbarios nacionales y extranjeros. Se sobrepuso una retícula de 2 × 2 km al mapa de la costa y de las dunas costeras de México para referir todos los registros que corresponden a 2180 sitios con 12,419 ejemplares de plantas. Se calcularon índices de diversidad, similitud, diversidad taxonómica y redundancia.Resultados clave: La flora registrada consta de 153 familias, 897 géneros y 2075 especies de plantas vasculares, las cuales representan 9.5% de la flora vascular de México. Las cinco colecciones con índices de redundancia altos IR≥0.7 son los herbarios de la Universidad Nacional Autónoma de México (MEXU, IR=0.9), del Centro de Investigación Científicas de Yucatán (CICY, IR=0.8), y los del Centro de Investigaciones Biológicas del Noroeste (HCIB), el Instituto de Ecología, A.C. (XAL) y el del Museo de Historia Natural de San Diego (SD), cada uno con un IR de 0.7. Se reconocen cinco regiones florísticas que corresponden a los mares de México. El Pacífico Norte tiene mayor diversidad taxonómica y el Pacífico Sur menor diversidad taxonómica. El Golfo de California, Golfo de México y Mar Caribe tienen diversidades taxonómicas similares. Las especies con más registros son Trianthema portulacastrum (165), Croton punctatus (107), Echites umbelllatus (106) e Ipomoea pes-caprae (90). Por el carácter de ecotono de las dunas costeras, la mayoría de las especies se comparten con los tipos de vegetación vecinos (selvas, matorrales, y humedales como las marismas y manglares).Conclusiones: Esta primera lista de la flora en playas y dunas de México es la base para múltiples estudios florísticos regionales y locales, biogeográficos, y ecológicos; además, que será importante para su uso en temas de impacto ambiental y manejo costero