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.