Search

The provision of climate services has the potential to generate adaptive capacity and help coffee farmers become or remain profitable by integrating climate information in a risk-management framework. Yet, in order to achieve this goal, it is necessary to identify the local demand for climate information, the relationships between coffee yield and climate variables, farmers’ perceptions, and to examine the potential actions that can be realistically put in place by farmers at the local level. In this study, we assessed the climate information demands from coffee farmers and their perception on the climate impacts to coffee yield in the Samalá watershed in Guatemala. After co-identifying the related candidate climate predictors, we propose an objective, flexible forecast system for coffee yield based on precipitation. The system, known as NextGen, analyzes multiple historical climate drivers to identify candidate predictors, and provides both deterministic and probabilistic forecasts for the target season. To illustrate the approach, a NextGen implementation is conducted in the Samalá watershed in southwestern Guatemala. The results suggest that accumulated June-July-August precipitation provides the highest predictive skill associated with coffee yield for this region. In addition to a formal cross-validated skill assessment, retrospective forecasts for the period 1989-2009 were compared to agriculturalists’ perception on the climate impacts to coffee yield at the farm level. We conclude with examples of how demand-based climate service provision in this location can inform adaptation strategies like optimum shade, pest control, and fertilization schemes months in advance. These potential adaptation strategies were validated by local agricultural technicians at the study site.

The aim of this work is to assess the horizontal distribution of aerosols during winter and spring 2017, in San Juan city, Argentina, and its relationship with the land use. The concentration of PM2.5 at ground level in 54 points of the city and the aerosol optical deep were measured. A supervised classification to obtain a land use map was performed. Statistical analysis was carried out considering 5 variables values in the 54 points, related to the particulate material (PM) emission: AOD, LST, NDVI, NDWI from satellite products and PM2.5 from field measurements. The data were analyzed considering the spatial, seasonal and meteorological variation, and the land use classes.The results indicate that 3 concentric rings can be considered in the studied area and 4 zones are distinguished: urban, peri-urban, periphery and industrial. The average PM2.5 concentrations was 18.7 μg/m3, and the season of maximum concentration was in winter. For AOD the average was 0.83, and the maximum registered during spring. PM2.5 concentrations presented a Pearson’s correlation coefficient with AOD higher than 0.65 in areas classified as peri-urban and industrial periphery. Regarding the meteorological variables, LST and wind showed the highest correlation with AOD and PM2.5. NDVI and NDWI present negative correlation with aerosol concentrations, so in areas with more vegetation and higher soil moisture which indicates that aeolian soil erosion is an important PM emission.

Despite continued forest loss and extensive demand for wood products throughout Guatemala, the locally managed and protected forests of Totonicapan remain some of the most intact within the country. Here, we study the growth rings of Guatemalan fir (Pinaceae, Abies guatemalensis Rehder, pinabete) at Totonicapan to assess environmental influences on tree growth and the potential vulnerability of these forests to climate change in the western highlands. We find that late summer and dry season precipitation are critical drivers in annual ring-width variability and that tree growth responds negatively to warm sea surface temperature anomalies in the eastern tropical Pacific. Considering our results in light of future climate model projections for Central America, we suggest that these forests will become increasingly susceptible to widespread drying and higher temperatures. Such shifts could fundamentally jeopardize an endemic and endangered tree species that has traditionally been preserved by K’iche’ communal governance and that is highly regarded for its ecosystem services and role in the Guatemalan economy. resumen: A pesar de la perdida continua de bosques y la amplia demanda de productos maderables en toda Guatemala, los bosques protegidos y manejados por las comunidades locales de Totonicapan forman parte de algunos de los mas intactos del pais. En este estudio analizamos los anillos del tronco arboreo de pinabete (Pinaceae, Abies guatemalensis Rehder) de Totonicapan para evaluar las influencias ambientales sobre el crecimiento arboreo y la vulnerabilidad de los bosques ante potenciales cambios en el ambiente en el altiplano del pais. Encontramos que la precipitacion al final del verano y la de la estacion seca son claves para la variabilidad anual del crecimiento arboreo y que los arboles responden negativamente a las anomalias calidas de las temperaturas de la superficie del mar en el Pacifico tropical oriental. Considerando nuestros resultados ante las proyecciones de modelos climaticos para Centroamerica, sugerimos que estos bosques van a ser cada vez mas susceptibles a sequias generalizadas y aumentos en la temperatura. Estos cambios pueden poner en peligro una especie ende-mica y amenazada que tradicionalmente ha sido conservada por la gobernanza comunal de los K’iche’ y que es altamente valorada por sus servicios ecosistemicos y su rol en la economia guatemalteca.

Guatemala's population is dependent on cash crops and subsistence agriculture, the yield of which depends on both the timing and quantity of rainfall. Detailed knowledge about Guatemala's past, cur...

Agroforestry systems maintain intermediate levels of biodiversity between natural forests and purely agricultural land-uses and may therefore increase connectivity or sustain biodiversity in fragmented forest landscapes. This hypothesis is tested by comparing the species richness and similarity in species composition between forest fragments and agroforestry systems in two landscapes in Guatemala. Connectivity indices were calculated based on the similarity of biodiversity held between forest and agroforestry. Tree and ant species richness was significantly higher for forest than agroforestry land-uses. Conversely, species richness of leaf hoppers (Cicadellidae) was lower in forests compared to agroforests. Chao-Sorensen estimates indicated a high proportion of ant species were shared (0.78–0.99) between different agroforestry land-uses and forest fragments, but lower proportions of tree (0.39–0.55) and leaf hopper species (0.42–0.65). Including the contribution of agroforestry systems in estimates of forest connectivity, based on their biodiversity relative to forest, substantially increased the land area rated with high connectivity (by 100–300%) and forest edge connectivity (by 70–170%), but had negligible impact on land area rated as dense forest. The major forest fragments in the two landscapes were linked by land rated as medium connectivity for forest biodiversity. Thus, agroforestry contributes to the capacity of the landscape to support biodiversity, but only partially increases connectivity between forest fragments in the two landscapes studied. If these benefits are to be sustained, consideration needs to be given to the incentives for land-owners to maintain agroforestry systems.

Drought in Guatemala has negative consequences for agriculture and potable water supplies, particularly in regions of the country with highly seasonal rainfall. General circulation models suggest that a decrease in both winter and summer rainfall over Central America is likely and imminent as a consequence of anthropogenic influences on the climate system. However, precipitation observations over the last several decades are equivocal. Here, we use an Abies guatemalensis tree-ring chronology from the Sierra de los Cuchumatanes to estimate January through March rainfall since the late seventeenth century. Our reconstruction shows that recent winter–spring rainfall from the region is not yet exceptional in the context of the last several centuries, has a significant yet variable decadal component, is associated with large-scale modes of ocean–atmosphere variability, and reveals evidence of past multiyear droughts.

The continued expansion of dendroclimatology into Mesoamerica requires the identification and evaluation of species whose rings can be precisely dated and then statistically compared with precipitation and temperature variability in order to make inferences about past climate. Here, we establish the basis for using Abies guatemalensis Rehder (Pinaceae) for climate reconstruction in Central America. Annual crossdating in this montane species is demonstrated at high-elevation sites in the Sierra de los Cuchumatanes in western Guatemala. We find that ring width is most strongly influenced by early growing season moisture conditions, controlled by late dry season rainfall, and negatively correlated with growing season temperature. Our chronology is also significantly negatively correlated with eastern tropical Pacific sea surface temperature anomalies. Our confirmation of annual chronology and the identification of a climatic signal in this species now allow its use in local and regional paleoclimate reconstructions, as well as ecological studies.

Non-point source water pollution is a key question in rural watersheds and it needs to be studied in order to prevent damages to ground and surface water quality. The main goal of this study is to analyze nutrient and chemical loads in groundwater and streams in Pampa region, Argentina. For studying groundwater loads, a set of 19 observation wells were installed in 2011, in western Buenos Aires. The wells were located at three landscape positions (upper, middle and lower hill) in seven agricultural fields and groundwater samples were monthly collected. As for surface water, two watersheds located in southeastern Buenos Aires, were chosen: Napaleofu creek Watershed (34.000 hectares) and Quequen Grande River watershed (938.000 hectares). Daily water samples were taken from the main stream from October 2011 to May 2013, at both watersheds. Water Samples collected from wells and streams, were analyzed to determine N, and chemical loads. A group of 11 herbicides and one insecticide frequently used by farmers in the watershed were chosen for the study. Nitrogen and chemical concentrations were analyzed considering rainfall events and also compared to critical limits. Preliminary results are presented from a subset of samples since remaining samples are currently being processed in laboratory. As for NO 3 -N concentration, most of wells presented variable concentration depending on monthly precipitation and landscape position. Considering 10 mg/L NO 3 -N as a standard limit, 52% of the observations exceed this value mostly related to unusual precipitations events at winter 2012. Nitrate-N concentration in streamflow at Quequen Grande River and Napaleofu creek were on average 5 ppm. NPS Pollution modeling is a second goal of this on-going research. SWAT validation results are also presented for one of the watersheds under study.