La participación de los humedales en el ciclo global del carbono (C) es de suma importancia, al actuar como sumideros de dicho elemento. La vegetación en los humedales es un factor que influencia el almacenamiento de C en dichos ecosistemas. En este estudio se investigó el almacenamiento de C en suelos de humedales arbóreos (HA) y herbáceos (HH) de agua dulce de la planicie costera de Veracruz, México. Los sitios estudiados fueron: Estero Dulce (ED), Tecolutla y Laguna Chica (LCH), Vega de Alatorre. Las densidades aparentes observadas oscilaron de 0.1 a 1.15 g cm3. El contenido promedio de C en LCH fue mayor en HA (13.30±0.11 %) que en HH (4.52±0.02 %). Sin embargo, en los humedales de ED el contenido de C fue similar tanto en HA (5.88±0.03 %) como HH (5.28±0.02 %). En HH de LCH, se observó aproximadamente 50 % menos contenido de C en el suelo en comparación con el contenido de C del HA. En ED, el C almacenado en HH fue sólo 7.15 % menor que en HA. Al comparar el almacenamiento de C total de los HA (35.04±4.0 kg C m-2) y HH (24.8±4.0 kg C m-2), no se observaron diferencias (P = 0.213). | Wetlands play an important role in the global carbon (C) cycle because they act as sinks of this element. Vegetation in the wetlands is a factor that influences C storage in these ecosystems. We investigated C storage in freshwater wetland soils with different types of vegetation (swamps and marshes) in the coastal plain of Veracruz, Mexico. The study sites were: Estero Dulce (ED), Tecolutla and Laguna Chica (LCH), Vega de Alatorre. Bulk densities observed ranged from 0.1 to 1.15 g cm3. Average C stored in LCH was higher in swamp (13.30±0.11 %) than in marsh soils (4.52±0.02 %). However, in ED the C content was similar in swamp (5.88±0.03 %) and marsh soils (5.28±0.02 %). In LCH marshes, there was approximately 50 % less total C in the soil compared to the C content in the swamps. In ED, the C stored in the marshes was only 7.15 % lower than the C stored in the swamps. When the total C storage of freshwater swamps (35.04±4.0 kg cm-2) and marshes (24.8±4.0 kg cm-2) was compared, there was no effect caused by the type of vegetation (P = 0.213).

Mediterranean wetlands show remarkable seasonal and annual variations in their hydroperiod, i.e. the period during which they are inundated. Climate change-induced hydroperiod reductions have been shown to affect marshland birds but more studies are needed to understand this process in Mediterranean wetlands. The present study shows the demographic response of the Common Reed-warbler Acrocephalus scirpaceus to an unusual and prolonged drought in the Tablas de Daimiel National Park wetland (central Spain). We used data from two constant effort mistnetting stations (2005–2013), and spatially explicit capture-recapture Jolly-Seber models. The Reed-warblers continued reproducing in a dry environment for three years after the start of a dry phase, despite progressive declines in productivity, and ultimately stopped nesting in the fourth year. After the recovery of water levels in subsequent years, the population required another four years to recover a size and productivity similar to those preceding the drought. This situation may be common in the near future given ongoing alterations of the hydroperiod in Mediterranean wetlands as a consequence of climate change and groundwater overexploitation. We also show that spatially explicit capturerecapture models allow the detection of changes in the populations of small passerines, and are an accurate approach to estimating their densities. —Jiménez, J., Hernández, J.M., Feliú, J., Carrasco, M. & Moreno-Opo, R. (2018). Breeding in a dry wetland. Demographic response to drought in the Common Reed-warbler Acrocephalus scirpaceus. Ardeola, 65: 247–259.

Aquifer systems present intrinsic properties such as vulnerability, which is identified as the potential risk of groundwater pollution by contaminants generated by human activity. When there are surface sources of pollution, usually there is a direct relationship between high vulnerability and decreased water quality. Nevertheless, this relationship is not observed in all aquifers and so the causative circumstances of inconsistencies between aquifer vulnerability and water quality have been investigated. This work addresses the vulnerability assessment of the Chapala Marsh area, Mexico, using SINTACS analysis. The Chapala Marsh aquifer is characterized by a granular structure and a fractured recharge zone; there are natural and anthropogenic sources of pollution. The results show discrepancies between the vulnerability indices and groundwater quality, as indicated by the existence of vulnerable areas with good water quality and vice versa. This is because the SINTACS method works well when contaminants have only vertical movement. For scenarios with lateral movement of contaminants, the method of geographic weighted regression (GWR) is used to model the influence of potential sources of contaminants on the water quality.