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The implementation of green infrastructure (GI) as Nature-Based Solutions (NBS) generates positive effects on the water ecosystem service in an urban context. Practices such as bioretention cells, green roofs, rain gardens, permeable pavements, and infiltration trenches contribute to treating large volumes of runoff and providing safe spaces for populations living in highly urbanized areas. With the aim to simulate these effects, a hydrological modeling was carried out using the i-Tree Hydro Plus model, which quantified the runoff generated from precipitation events and effective transformations (NBS) to cope with runoff. Eight scenarios were developed: a baseline scenario, five future scenarios with green infrastructure, a scenario with increased tree coverage, and a scenario with increased urbanization. Our hypothesis is that NBS would reduce runoff and increase permeable flow. The analysis of the feasibility of implementing the modeled green infrastructures was carried out through consultation with local stakeholders in the micro-watershed. We found that bioretention cells decrease runoff by 5%, green roofs by 4%, rain gardens by 4%, permeable pavements by 4.5%, and infiltration trenches by 7.5% compared to the baseline scenario where runoff accounts for 32% of water balance flows. The scenario of increased tree coverage had a similar behavior to the baseline scenario, indicating that efforts in this alternative would generate a limited impact on the reduction of runoff. With increased urbanization, impermeable flow increases up to 78%, which would generate floods. Implementing NBS would be feasible since this type of initiative is included in the agenda of many regulatory instruments of urban planning in Costa Rica.

espanolLa ocurrencia de heladas en zonas templadas de Mexico afecta seriamente el volumen y el valor de la produccion agricola, ocasionando importantes perdidas economicas para los productores y desabasto de alimentos. Las heladas tardias y tempranas son altamente peligrosas para el desarrollo de muchos cultivos, por lo que es importante desarrollar modelos sensibles de estimacion de riesgos que permitan caracterizar los regimenes locales de ocurrencia de heladas para tomar decisiones acertadas en la planeacion de la produccion. Este trabajo tiene como objetivo estimar las fechas de ocurrencia de heladas tardias y tempranas, asi como los periodos libres de heladas, mediante la estimacion de la probabilidad de ocurrencia desde un enfoque de eventos extremos. Se usan datos de temperatura minima diaria registrada en 77 estaciones meteorologicas del Estado de Mexico entre 1980 y 2010, tomados del CLICOM (Servicio Meteorologico Nacional, 2014). Se propone emplear una distribucion de valores extremos para modelar las fechas de ocurrencia de las ultimas heladas primaverales y las primeras heladas otonales, ya que esta familia de distribuciones presenta mayor sensibilidad en el analisis de colas para estimacion de riesgos. Los resultados se presentan en mapas de riesgo en terminos de probabilidad de ocurrencia de heladas. Se concluye que la distribucion Weibull presento el mejor ajuste a los datos de acuerdo con el Criterio de Informacion de Akaike (AIC), y permitio caracterizar satisfactoriamente el regimen de ocurrencia de heladas en el Estado de Mexico. EnglishThe occurrence of frosts in temperate zones of Mexico seriously affects the volume and value of agricultural production, causing significant economic losses for producers and food shortages. Late and early frosts are highly dangerous for the development of many crops, in this sense it is important to develop sensitive risk estimation models to characterize local frost occurrence regimes to make sound decisions in production planning. This paper aims to estimate the dates of occurrence of late and early frosts, as well as the frost-free periods, by estimating the probability of occurrence from the approach of an extreme event. Daily minimum temperature data recorded in 77 meteorological stations in Mexico State between 1980 and 2010 are used, taken from CLICOM (National Meteorological Service, 2014). It is proposed to use a distribution of extreme values to model the dates of occurrence of the last spring frosts and the first autumn frosts since this family of distributions presents greater sensitivity in the tails analysis for risk estimation. The results are presented on risk maps in terms of the probability of frost occurrence. It is concluded that the Weibull distribution presented the best fit to the data according to the Akaike Information Criterion (AIC), which has enabled successfully characterize the regime of frost occurrence in Mexico State.

Improved quantification of water partitioning is needed to inform sustainable, integrated land and water management. Spatially-distributed, process-based ecohydrological models are promising tools for achieving this; however, such models typically have many parameters that require estimation from data. Utilising an extremely rich plot-scale dataset incorporating energy (net radiation, temperature, and latent and sensible heat), hydrological (soil moisture, sap flow and actual evapotranspiration) and vegetation (net primary productivity and structure) components, we investigated which types of observation best constrain the parameters of a complex ecohydrological model (EcH2O-iso) for simulation of water partitioning. Our experimental site was situated within one of the largest coffee agroforestry systems in Costa Rica and experiences high energy inputs and intense rainfall events, thus adding further complexity to the robust simulation of hydrological processes. A series of calibration exercises were undertaken based on combinations of the different observation types. In each case, 100 behavioural parameter sets were chosen following 100,000 Monte Carlo simulations. The “flux mapping” approach was then used to quantify the percentage contribution made by different simulated fluxes to total model outflows (e.g., contributions of transpiration, soil evaporation and interception evaporation to total evapotranspiration), in order to assess how consistently plot hydrology was simulated by the retained parameter sets. Additionally, PCA analysis of performance metrics (including those for observations not used in the given calibration) was undertaken to reveal how contrasting observation types “pull” the model in different directions and, thus, affect its ability to capture the dynamics of each type simultaneously. From this work, we are able to provide guidance on how different ecohydrological datasets may be optimally combined in model calibration. This has implications not only for reducing uncertainty in modelling studies underpinning land and water management, but also for designing future field campaigns such that collection of the most valuable data can be prioritised.

As a result of canopy interception and transpiration, trees are often assumed to have negative effects on the local hydrological budget resulting in reduced soil and groundwater resources. However, it has also been shown that trees can have positive effects through reducing surface run-off and improving soil infiltrability and groundwater recharge, especially in many tropical ecosystems characterized by high rain intensity and degradation-prone soils. In this study, we used isotopic measurements of soil water to better understand the main processes by which trees influence local soil water dynamics within a tropical pasture with scattered tree cover in the Copan River catchment, Honduras. We also determined the stable isotope signature of xylem water in grasses and trees to assess potential competition for water sources during the wet and dry seasons. During the wet season, when soil water availability was not limiting, both grasses and trees primarily utilized soil water near the soil surface (i.e., 0–10 cm). In contrast, during the dry season, we observed niche partitioning for water resources where grasses primarily utilized soil moisture at deeper soil depth (i.e., 90–100 cm) while trees relied heavily on groundwater. Moreover, isotopic data of soil water suggest that trees reduce evaporative water losses from the soil surface, as indicated by the lack of correlation between soil water content and lc-excess (line condition excess) values of surface soil water under trees, and enhance preferential flow as suggested by less negative lc-excess values under trees compared to open areas during the dry season. Taken together, our findings provide further support that trees can have positive effects on the local water balance with implication for landscape management, promoting the inclusion of scattered trees to provide water ecosystem services in silvopastoral systems, adding to other ecosystem services like biodiversity or carbon sequestration.

espanolHaiti es una nacion con grandes retos ambientales y sociales. La alta deforestacion, falta de planificacion territorial, inestabilidad politica y economica, y una poblacion ejerciendo presion sobre recursos naturales son factores caracteristicos de Haiti que se manifiestan en su dinamica territorial. En este articulo analizamos los procesos de cambio de cobertura de la tierra en el Departamento Sur de Haiti de 1973 al 2017 y la relacion de estos procesos con ciertas variables socioeconomicas y biofisicas asociadas al cambio global y sus componentes. Para ello utilizamos imagenes satelitales Landsat, repositorios de datos publicos, metodologias para el analisis de la direccionalidad del cambio, asi como analisis estadisticos correlacionales. Los resultados muestran una fluctuacion marcada en el cambio de areas de cultivos, una relacion parcial del suelo desnudo con zonas deforestadas, asi como una disminucion en la cobertura boscosa tras una serie de eventos hidrometeorologicos y sociopoliticos presentados en Haiti. Ademas, encontramos que el cambio de matorral se asocio significativamente con las tasas de cambio de poblacion, de temperatura y del Indice de Desarrollo Humano (IDH), mientras que la tasa de cambio de precipitacion influyo significativamente en el cambio de la cobertura de cultivos. Por otra parte, los cambios en el suelo desnudo tuvieron relacion significativa con la tasa de cambio de poblacion. Finalmente, ninguna de las variables consideradas se asocio significativamente con el cambio espaciotemporal de las coberturas urbano y bosque. EnglishHaiti as a country faces great environmental and societal challenges. Haiti is characterized by a high deforestation, lack of territorial planning, political and economic instability, and a growing population exerting pressure on natural resources. In this article, we analyze the historic land cover change in the Southern Department of Haiti from 1973 to 2017 and the relationship to socioeconomic and biophysical variables. All variables under change together are considered as the holistic definition of global change. We used Landsat satellite images, public data repositories and statistical correlations to analyze the directionality of the above-mentioned global change in Haiti. The results showed a marked fluctuation of crop areas, a relation of bare soil with deforested areas, as well as a decrease in forest cover after a series of hydrometeorological and sociopolitical events. In addition, we found that changes in brush area were significantly associated with the rates of change in population, temperature and the Human Development Index (HDI), while the rate of change in rainfall significantly influenced the change in crop coverage. On the other hand, changes in bare soil had a significant relationship with the rate of population change. Finally, none of the variables considered was significantly correlated with the spatiotemporal change of urban and forest coverage.

Se presenta una evaluación de la vulnerabilidad ante la escasez de agua y sequía en la ciudad de La Paz (BCS). Se utilizó el Marco de Capitales de la Comunidad (MCC) para estimar la vulnerabilidad como un sistema integrado por siete sub-sistemas: humano, social, político, financiero, físico, natural y cultural, mediante un análisis de situación biofísica, cálculo de índices, y la identificación de medidas y estrategias que ayudan a mejorar la capacidad adaptativa de la comunidad. Se obtiene la vulnerabilidad integral, que se representó espacialmente en la zona de estudio. La Paz presenta una vulnerabilidad media y es necesario fortalecer las capacidades de la comunidad priorizando el trabajo comunidad-gobierno, no sólo para hacer frente a este tipo de eventos sino para mejorar también la calidad de vida de las personas.

Spatially and seasonally distributed information on transpiration (T) fluxes is limited in the tropics. Here, we applied a coupled isotope mass balance model to separate water fluxes of T and evapotranspiration (ET) from precipitation (P). The mean annual T was estimated at a resolution of 100 m for Costa Rica (51,100 km2) and a partitioning of monthly T and evaporation (E) for the 2370-km2 San Carlos catchment. The dominant flux in the forest ecosystems was T with a mean annual T of 1086 mm that ranged from 700 mm in Tropical Montane Very Humid Forest to 1400 mm in Subtropical and Tropical Low Montane Rainforests. We estimated an average 85% of ET was T, which is concurrent with expectations for forested tropical regions, but varied according to model parameterization and data sources. A model comparison exercise showed a range of mean annual T estimates from 988 to 1465 mm and a range of T/P from 0.35 to 0.5 with temperature and relative humidity exhibiting the highest impact on the model results. Across Costa Rica, we estimated an average loss of precipitation by T of 38% (1085 mm), whereas interception (I) constitutes 10% (230 mm) and direct evaporation (E) only 7% (192 mm). Similarly, the results at the catchment scale indicated that monthly T contributes 76% (85-mm monthly average) to total ET and E corresponds to 24% (24-mm monthly average). The T rates exhibited an opposite seasonality to rainfall with highest T over the drier months from December to April with a peak in March (101–144 mm) and the minimum T in September (53–71 mm). Around 17% (79–130 mm) of precipitation over the catchment area is lost to T, both E (10–35 mm) and I (15–38 mm) correspond to 5%. Despite the inherent uncertainties of the data assumptions and simplifications, including data interpolation errors, the coupled isotope mass balance model showed in comparison to other global products reasonable water partitioning for different ecosystems in Costa Rica and the San Carlos catchment area. These results can help to evaluate the impact of land cover conversion on the hydrological cycle in Costa Rica, and the simple isotope-based model could be transferred to different biomes of the tropics. Universidad Nacional, Costa Rica Centro Agronómico Tropical de Investigación y Enseñanza, Costa Rica Universidad Técnica de Braunschweig, Alemania Universidad de Costa Rica, Costa Rica Universidad de Aberdeen, Reino Unido Escuela de Química

Numerous socio-economic activities depend on the seasonal rainfall and groundwater recharge cycle across the Central American Isthmus. Population growth and unregulated land use changes resulted in extensive surface water pollution and a large dependency on groundwater resources. This work combines stable isotope variations in rainfall, surface water, and groundwater of Costa Rica, Nicaragua, El Salvador, and Honduras to develop a regionalized rainfall isoscape, isotopic lapse rates, spatial–temporal isotopic variations, and air mass back trajectories determining potential mean recharge elevations, moisture circulation patterns, and surface water–groundwater interactions. Intra-seasonal rainfall modes resulted in two isotopically depleted incursions (W-shaped isotopic pattern) during the wet season and two enriched pulses during the mid-summer drought and the months of the strongest trade winds. Notable isotopic sub-cloud fractionation and near-surface secondary evaporation were identified as common denominators within the Central American Dry Corridor. Groundwater and surface water isotope ratios depicted the strong orographic separation into the Caribbean and Pacific domains, mainly induced by the governing moisture transport from the Caribbean Sea, complex rainfall producing systems across the N-S mountain range, and the subsequent mixing with local evapotranspiration, and, to a lesser degree, the eastern Pacific Ocean fluxes. Groundwater recharge was characterized by (a) depleted recharge in highland areas (72.3%), (b) rapid recharge via preferential flow paths (13.1%), and enriched recharge due to near-surface secondary fractionation (14.6%). Median recharge elevation ranged from 1,104 to 1,979 m a.s.l. These results are intended to enhance forest conservation practices, inform water protection regulations, and facilitate water security and sustainability planning in the Central American Isthmus. Universidad Nacional de Costa Rica/[SIA-0482-13]/UNA/Costa Rica Universidad Nacional de Costa Rica/[SIA-0101-14]/UNA/Costa Rica Universidad Nacional de Costa Rica/[SIA-0236-16]/UNA/Costa Rica Universidad Nacional de Costa Rica/[SIA-411-17]/UNA/Costa Rica Universidad Nacional de Costa Rica/[SIA-414-17]/UNA/Costa Rica Universidad Nacional de Costa Rica/[SIA-0378-14]/UNA/Costa Rica Empresa de Servicios Públicos de Heredia/[]/ESPH S.A./Costa Rica International Atomic Energy Agency/[COS/7/005]/IAEA/Austria International Atomic Energy Agency/[RC-19747]/IAEA/Austria International Atomic Energy Agency/[RLA/7/024]/IAEA/Austria International Atomic Energy Agency/[NIC/5/009]/IAEA/Austria European Union/[DCIENV 2014/350-470]/EU/Países Bajos Nature Conservancy/[Coca Cola FEMSA-TNC]/TNC/Estados Unidos Universidad de Costa Rica/[University of Costa Rica Research Council]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Física

Despite the widely held assumption that trees negatively affect the local water budget in densely planted tree plantations, we still lack a clear understanding of the underlying processes by which canopy cover influences local soil water dynamics in more open, humid tropical ecosystems. In this study, we propose a new conceptual model that uses a combination of stable isotope and soil moisture measurements throughout the soil profile to assess potential mechanisms by which evaporation (of surface soil water and of canopy‐intercepted rainfall) affects the relationship between surface soil water isotopic enrichment (lc‐excess) and soil water content. Our conceptual model was derived from soil water data collected under deciduous and evergreen plants in a shade grown coffee agroforestry system in Costa Rica. Reduced soil moisture under shade trees during the “drier” season, coinciding when these trees were defoliated, was largely the result of increase soil water evaporation as indicated by the positive relationship between soil water content and lc‐excess of surface soil water. In contrast, the evergreen coffee shrubs had a higher leaf area index during the “drier” season, leading to enhanced rainfall interception and a negative relationship between lc‐excess and soil water content. During the wet season, there was no clear relationship between soil water content and between lc‐excess of surface soil water. Greater surface soil water under coffee during the dry season may, in part, explain greater preferential flow under coffee compared with under trees in conditions of low rainfall intensities. However, with increasing rainfall intensities during the wet season, there was no obvious difference in preferential flow between the two canopy covers. Results from this study indicate that our new conceptual model can be used to help disentangling the relative influence of canopy cover on local soil water isotopic composition and dynamics, yet also stresses the need for additional measurements to better resolve the underlying processes by which canopy structure influences local water dynamics.

Huit ans de travaux de recherche sur les services écosystémiques dans une grande ferme caféière du Costa Rica (observatoire collaboratif Coffee-Flux, en système agroforestier à base de caféiers sous de grands arbres d'Erythrina poeppigiana, surface projetée de couronne de l'ordre de 16 %) ont suggéré plusieurs applications pour les agriculteurs et les décideurs. Il est apparu que de nombreux services écosystémiques dépendaient des propriétés du sol (ici des Andisols), en particulier de l'érosion, de l'infiltration, de la capacité de stockage de l'eau et des éléments nutritifs. Nous confirmons qu'il est essentiel de lier les services hydrologiques et de conservation au type de sol en présence. Une densité adéquate d'arbres d'ombrage (plutôt faible ici) permet de réduire la sévérité des maladies foliaires avec, en perspective, une réduction de l'usage de pesticides-fongicides. Un simple inventaire de la surface basale au collet des caféiers permet d'estimer la biomasse souterraine et la moyenne d'âge d'une plantation de caféiers, ce qui permet d'évaluer sa valeur marchande ou de planifier son remplacement. Le protocole de calcul actuel pour la neutralité carbone des systèmes agroforestiers ne prend en compte que les arbres d'ombrage, pas la culture intercalaire. Dans la réalité, si on inclut les caféiers, on se rapproche très probablement de la neutralité. Des évaluations plus complètes, incluant les arbres, les caféiers, la litière, le sol et les racines dans le bilan en carbone du système agroforestier sont proposées. Les arbres d'ombrage offrent de nombreux servies écosystémiques s'ils sont gérés de manière adéquate dans le contexte local. Par rapport aux parcelles en plein soleil, nous montrons qu'ils réduisent l'érosion laminaire d'un facteur 2, augmentent la fixation de l'azote (N2) atmosphérique et le pourcentage d'azote recyclé dans le système, réduisant ainsi les besoins en engrais. Ils réduisent aussi la sévérité des maladies foliaires, augmentent la séquestration de carbone, améliorent le microclimat et atténuent substantiellement les effets des changements climatiques. Dans notre étude de cas, aucun effet négatif sur le rendement n'a été enregistré., Eight years of studying coffee ecophysiology and monitoring ecosystem services (ES) in a large coffee farm in Costa Rica revealed several practical recommendations for farmers and policy makers. The cropping system studied within our collaborative observatory (Coffee-Flux) corresponds to a coffee-based agroforestry system (AFS) under the shade of large trees of Erythrina poeppigiana (16 % of canopy cover). A lot of ES and disservices depend on local soil properties (here Andisols), especially erosion/infiltration, water/carbon and nutrient storage capacity. Therefore, for ES assessment, the type of soil is crucial. An adequate density of shade trees (rather low here) reduced the severity of leaf diseases with the prospect of reducing pesticide-fungicide use. A simple inventory of the basal area at collar of the coffee plants allowed estimating the belowground biomass and the average age of the plantation, to judge of its market value and to decide when to replace it. Coffee farms are probably much closer to C neutrality than predicted by the current C-Neutral protocol, which only considers shade trees. More comprehensive assessments, including trees, coffee, litter, soil, and roots in the C balance of the AFS are proposed. Shade trees offer many ES if they are adequately managed in the local context. As compared to full sun conditions, shade trees may (i) reduce laminar erosion by a factor of 2, (ii) increase N2 fixation and the % of N recycled into the system, thus reducing fertilizer requirements, (iii) reduce the severity of leaf diseases, (iv) increase C sequestration, (v) improve the microclimate, and (vi) substantially reduce the effects of climate change. In our case study, no negative effect on coffee yield was found.

We report the single step synthesis of several 3-arylindanes and related compounds via a formal [3+2] cycloaddition. A study of the influence of the aromatic ring substitution pattern on the reaction was carried out.

We tested the hypothesis that trees have measurable effects on infiltrability, macroporosity, and preferential flows in agrosilvopastoral systems. Managing agricultural systems for water conservation is a critical component of sustainable systems. We investigated the relationship between infiltrability and the distance to the nearest tree, and whether differences in macroporosity can account for differences in infiltrability. In both systems, preferential soil water flows were dominant compared to matrix flow. Trees in the pasture landscape improved infiltrability and preferential flow but had no significant effect in the coffee agroforestry system. After comparing rainfall intensity and frequency data to the measured infiltrability values, we conclude that trees in the pasture system reduce surface runoff at the highest observed rainfall intensities (>50 mm h −1 ). The volcanic soils of the coffee plantation are less degraded and their high natural permeability has been maintained. Since the coffee plants at this site are established (40 years) perennial vegetation with substantial residues and extensive root systems like trees, they improve soil physical properties similarly to trees. Trees increase hydrologic services in pasture lands, a rapidly expanding land use type across Latin America, and therefore may be a viable land management option for mitigating some of the negative environmental impacts associated with land clearing and animal husbandry. However, in land management practices where understorey perennial vegetation makes up a large proportion of the cover, such as for coffee agroforestry systems, the effect of trees on infiltration-related ecosystem services could be less pronounced

Planning processes in watersheds imply complex decisions with limited resources, consequently, to know where in a watershed our money, time and effort will produce the bigger impacts is the main reason to prioritize goals and intervention areas into a watershed. With this logic, the Program Focuencas II started to work with some common factors and their implications to select specific criteria to prioritize areas in its “laboratory sub watersheds”. Among these factors we have: (i) potable water to human consumption, (ii) floods, (iii) landslides and (iv) sedimentation in water bodies, to start defining the possible territory to prioritize as guides to work in every “sub watersheds” (two in Honduras: La Soledad micro-watershed and Copan river sub-watershed, and two in Nicaragua: sub-watersheds of Aguas Calientes and Jucuapa).

The current study shows the process and the results of a methodology proposed to contribute with the issue of how to evaluate the adaptation to climate variability and future climate change. The proposed methodology consists of a standard to evaluate farmer’s adaptation to climate variability, mainly due to drought in watersheds in Central America; and was created with contributions from experts and professionals around this region. The phases for this process were: (1) literature review about the topic, (2) development of a preliminary standard, (3) expert interviews for the evaluation of this preliminary standard, (4) construction of a standard to evaluate the issue of adaptation to climate variability emphasizing drought through contributions from experts and their preliminary evaluations, (5) applicability test of this standard for the evaluation of climate variability under real conditions and (6) application of this standard through a case study in the Aguas Calientes river sub-watershed in Nicaragua, which permanently undergoes drought problems and climate variability. This standard has five main principles that go from the general, considering regional and national policies and institutionalism, to the specifics at the level of watersheds. In addition to those principles, the standard contains ten criteria, 26 indicators and 51 verifiers distributed among the main five principles. In the process for testing this standard in the Aguas Calientes river watershed in Nicaragua, the score for the general applicability to this standard was middle-level (score of 3 in a scale of 1 to 5), although, for the main principles of this standard, the score was four (high).