Climate change is at the top of the development agenda in Central America. This region, together with the Caribbean, is highly vulnerable to the effects of climate change in Latin America. Climate change is manifesting itself through higher average temperatures and more frequent droughts that result in higher water stress, and through the rising frequency of extreme weather events such as tropical storms, hurricanes, floods and landslides, all of which pose significant challenges in the rural water supply and sanitation sector. The paper starts with a review of the historic data on temperature and precipitation trends in Central America and particularly at the regional level in Nicaragua. The data reveal a clear trend of the growing climate variability, increased water stress for crops, and greater frequency of extreme weather events. The rising intensity and frequency of ex-treme weather events is among the most critical risks to the region's development agenda, and they translate into high economic losses. This paper examines the impacts and implications of potential climate change on water resources in Nicaragua and makes key recommendations to integrate climate change and rural water supply and sanitation policies and programs in a way that increase resilience to current and future climate conditions. | 0

Uruguay has a dense hydrographic network, nevertheless the knowledge of the aquatic macroinvertebrate community is still lacking. In recent decades afforestation with exotic species has increased which has produced changes in riparian vegetation of some rivers. The aim of this research was to determine the composition and trophic structure of macroinvertebrate community and its relationship to some physicochemical parameters in eight streams where the native forest is still well preserved and provide the basis for future studies. Samples were collected from December 2006 to December 2007. Temperature, dissolved oxygen, pH and conductivity were measured in situ. Taxonomic composition and abundance were determined, a principal component analysis and a canonical correspondence analysis were carried out with the physico-chemical and biological parameters. The alpha diversity was calculated using the Shannon-Weaver (H'), dominance of Simpson (D) and Pielou evenness indexes (J'). Beta diversity was determined employing similarity index of Bray-Curtis. A total of 1 291 specimens belonging 92 taxa were recorded. The most abundant taxa were Ephemeroptera (36%), Amphipoda (17%) and Coleoptera (12%). The streams show high diversity and low dominance. Conductivity, pH, and temperature were the main factors in determining the macroinvertebrate distribution and composition.

V. Bonnesoeur, B. Locatelli, B.F. Ochoa-Tocachi, 'Impactos de la forestaci�n en el agua y los suelos de los Andes: �Qu� sabemos? Resumen de pol�ticas', Forest Trends-Proyecto, Lima, Peru, 2019 | En respuesta a los compromisos internacionales (por ejemplo, la Iniciativa 20×20 y el Desaf�o de Bonn) o a las demandas locales y nacionales de protecci�n de la madera y de las cuencas, varios pa�ses andinos est�n restaurando la cobertura forestal, con la expectativa de mejorar los servicios ambientales. Los servicios ambientales relacionados con el agua, como el suministro de agua, la regulaci�n hidrol�gica y el control de la erosi�n, son especialmente importantes para sostener la vida de m�s de 50 millones de pobladores andinos. En las �ltimas d�cadas, cambios r�pidos e importantes en la cobertura forestal, a trav�s de la deforestaci�n y la forestaci�n, han modificado de manera considerable los servicios hidrol�gicos en los Andes

Changes in groundwater recharge associated with variations in land use were analysed with a focus on the role of afforestation on the east coast of Buenos Aires, Argentina. The growth of the population related to such changes was considered, linking water consumption to variations in recharge. A multi-temporal analysis was carried out using aerial photographs for the years 1957, 1975, 1981 and 2016, differentiating three types of cover: bare soil, forested soil and grassland. Water balances for each type of land use and groundwater recharge were estimated. In the forested soil, a reduction in recharge over time can be observed and it can be appreciated that forest expansion occurs at the expense of the sand-dune area, which offers the greatest possibilities for infiltration. At present, the water consumption, which depends solely on the groundwater reserves, is lower than the recharge, but this relationship is reversed during the tourist season. According to the estimated projections, the drinking water supply would be compromised in the coming decades, reaching a critical point or level of collapse as from 2070. This proves that it is essential for the policies and projects aiming at afforestation for different purposes to take into consideration the role of this change in land use when assessing the sustainability of the associated water resources.

Although impacts of land-use changes on groundwater recharge have been widely demonstrated across diverse environmental settings, most previous research has focused on the role of agriculture. This study investigates recharge impacts of tree plantations in a century-old experimental forest surrounded by mixed-grass prairie in the Northern High Plains (Nebraska National Forest), USA. Recharge was estimated using solute mass balance methods from unsaturated zone cores beneath 10 experimental plots with different vegetation and planting densities. Pine and cedar plantation plots had uniformly lower moisture contents and higher solute concentrations than grasslands. Cumulative solute concentrations were greatest beneath the plots with the highest planting densities (chloride concentrations 225–240 % and sulfate concentrations 175–230 % of the grassland plot). Estimated recharge rates beneath the dense plantations (4–10 mm yr⁻¹) represent reductions of 86–94 % relative to the surrounding native grassland. Relationships between sulfate, chloride, and moisture content in the area’s relatively homogenous sandy soils confirm that the unsaturated zone solute signals reflect partitioning between drainage and evapotranspiration in this setting. This study is among the first to explore afforestation impacts on recharge beneath sandy soils and sulfate as a tracer of deep drainage.