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February 2005 - February 2017
Publications
Publications (66)
Caracterización biofisica y Ecohidrología de los páramos de Colombia
Ecohydrology is a novel science that integrates ecological and hydrological aspects of terrestrial ecosystems. In general terms, the hydrological functioning of ecosystems is studied as the function of ecological processes, by explaining their dynamics as the response of specific climate conditions, vegetation, soils and anthropic activities. Durin...
Neotropical montane ecosystems are diverse and complex, ranging from glaciers, on top of highest mountains (above 4500 masl), with no vegetation at all, to páramo ecosystems with short vegetation (between 3000 and 4500 masl), mostly herbaceous and shrubs, and to montane forest with larger tree size and abundant epiphytes hanging from tree branches...
The páramos are Neotropical alpine tundra‐like ecosystems which play a crucial role as biodiversity hotspots but also act as water sources for the inter‐Andean regions and cities. Improving our understanding of hydrological processes, here evapotranspiration, is crucial, especially in the context of global changes. In páramos, most research have fo...
The occurrence of annual growth rings in tropical trees—the result of the seasonal activity of vascular cambium—has been explained by seasonal water deficit or flooding periods. However, little is known about the drivers of annual tree‐ring formation under tropical hyper‐humid conditions without clear seasonal dry periods or flooding (ever‐wet cond...
Ecohydrology is a novel science that integrates ecological and hydrological aspects of terrestrial ecosystems. In general terms, the hydrological functioning of ecosystems is studied as the function of ecological processes, by explaining their dynamics as the response of specific climate conditions, vegetation, soils and anthropic activities. Durin...
The “hierarchy of factors” hypothesis states that decomposition rates are controlled primarily by climatic, followed by biological and soil variables. Tropical montane forests (TMF) are globally important ecosystems, yet there have been limited efforts to provide a biome‐scale characterization of litter decomposition. We designed a common litter de...
Governments are increasingly committing to significant ecological restoration. However,
the impacts of forest restoration on local hydrological services are surprisingly poorly understood.
Particularly, limited information is available about the impacts of tree planting on soil infiltration
processes and runoff pathways. Thus, we investigated the s...
Tropical montane cloud forests (TMCF) receive additional (‘occult’) inputs of water from fog and wind‐driven rain. Together with the concomitant reduction in evaporative losses, this typically leads to high soil moisture levels (often approaching saturation) that are likely to promote rapid subsurface flow via macropores. Although TMCF make up an e...
El problema de la disponibilidad de agua y su importante papel en el sector agrícola, específicamente en la presión que existe actualmente por el recurso hídrico, pero además en países como Colombia donde el cultivo del café tiene una importancia histórica, cultural y económica, lo que hace necesario un estudio de la huella hídrica de este cultivo...
Tropical montane cloud forests (TMCF) receive additional (‘occult’) inputs of water from fog and wind-driven rain. Together with the concomitant reduction in evaporative losses, this typically leads to high soil moisture levels (often approaching saturation) that are likely to promote rapid subsurface flow via macropores. Although TMCF make up an e...
In tropical highlands of the northern Andes, known as páramos, fog incidence is very frequent. Its quantification is not yet clear, mostly because of the complexity of distinguishing between fog and low‐intensity rainfall. Moreover, there is uncertainty about the performance of the various types of gauges used to capture fog in this ecosystem. This...
Montane ecosystems around the world are found from the equator to the poles and occupy approximately one fifth of the surface of continents and islands (Ives et al. 1997). In South America, the Andes, as the longest ridge in America, extends over approximately 1.5 million km², running from 11° N to 23° S, with altitudes up to 6000 masl. The tropica...
Litter decomposition plays a central role in carbon and nutrient cycling, including ecosystem productivity, soil physicochemical properties, the structure of soil organism communities, and the dynamics of food webs. The "hierarchy of factors" hypothesis that states that on a global scale, decomposition rates are controlled primarily by climatic, fo...
Mediante el empleo de un modelo de simulación de procesos de cuencas hidrográficas, y según dos escenarios basados en dos Modelos Climáticos Globales, se caracterizan y cuantifican posibles impactos del cambio climático sobre variables ecohidrológicas en una cuenca estratégica de la Región Central de Venezuela.
Se estimaron posibles impactos del cambio climático sobre variables ecohidrológicas en la cuenca media del río Pao (estado Cojedes, región central de Venezuela). Para ello, se empleó el modelo SWAT con información de clima histórico (1976-1992) y 50 años a futuro (2026-2042); en los escenarios de cambio climático RCP4.5 y 8.5. La información climát...
Los “bosques mesófilos de montaña” son ecosistemas que se caracterizan por el nivel de estratos arbóreos, abundantes helechos y epífitas. Actualmente esta formación vegetal se encuentra en forma de relictos en algunas de las cañadas del país, por lo que es importante conservar este ecosistema que ocupa menos de 1% del territorio nacional y que tien...
The "tropical mountain cloud forest" are ecosystems characterized by the level of tree strata, abundant ferns and epiphytes. Currently this type of vegetation exists in the form of relicts in some of the country's glens, so it is important to conserve this ecosystem that occupies less than 1% of the national territory and has a high value in the fa...
Possible impacts of climate change on ecohydrological variables in the middle Pao river basin (Cojedes state, central region of Venezuela) were estimated. For this, the SWAT model was used with historical climate information (1976 -1992) and 50 years adjusted future (2026-2042) for the RCP 4.5 and 8.5 climate change scenarios. Future climate inform...
Páramos are high elevation tropical ecosystems in northern Andes, with large water yield and water regulation. One of the main and representative species growing in these páramos is the genus Espeletia, known as frailejones. There is a lack of knowledge of Espeletia ecophysiology, maybe due to its unusual anatomical modifications and the specific c...
Los páramos son ecosistemas que se caracterizan por una alta humedad relativa, alta frecuencia de niebla y por tener una vegetación arbustiva y herbácea adaptada a las condiciones de alta montaña. En condiciones naturales estos ecosistemas presentan una oferta hídrica alta, entre otros servicios ecosistémicos, sin embargo, esto cambia cuando son de...
Páramos are equatorial alpine ecosystems characterized by a high air humidity, frequency of fog and the presence of shrub and herbaceous vegetation adapted to the specific equatorial alpine conditions. Under natural conditions these ecosystems present a high water yield, among other ecosystem services, however, this changes when they are degraded....
Páramos are high-altitudinal neotropical ecosystems located in the upper regions of the northern Andes. Their hydrology is characterised by an extraordinarily high runoff ratio. One major contributing mechanism is thought to be fog occurrence, which is common in the páramos and occurs by the cooling of near-surface moist air, as it is forced to hig...
p>Páramo ecosystems are located on the upper parts of the tropical mountains, below the snow line areas or in isolated areas where no glacier ecosystems occur. These ecosystems are considered important for their biodiversity, but mainly because they are permanent source of water for populations located at the upper and middle parts of the Andes. Re...
Land use conversion and climate change threaten the hydrological services from tropical montane cloud forests (TMCFs), but knowledge about cloud forest ecohydrology and the effects of global change drivers is limited. Here, we present a synthesis of research that traced the hydrologic sources, fluxes and flowpaths under different land cover types d...
The Amazonia rainforest is the most complex biome on earth, both in its structure and species diversity, besides it plays an important role in the regulation of regional and global climate. Ecohydrological studies of Amazon rainforests may serve different purposes: to understand the transfer processes between soils, vegetation and atmosphere, to as...
Land use conversion and climate change threaten the hydrological services from tropical montane cloud forest (TMCFs) regions, but knowledge about the ecohydrological mechanisms controlling catchment response is limited. This project traced the hydrologic sources, fluxes and flowpaths across the atmosphere-plant-soil-stream continuum under different...
As montane cloud forests (MCF) are considered a strategic resource for their
water yield, understanding the processes controling their hydrological function is fundamental. As part of a larger project studying the ecohydrological factors controling watershed responses to land use change in the MCF zone of the state of Veracruz in eastern Mexico, th...
Soil water flux is qualified as a dynamic processes that regulate soil chemical reactions, physical and biological events, which in turn influence plant growth and nutrition. Water flow in soils is considered of environmental importance, since it influences the distribution and transmission of water, solutes and contaminants through the vadose zone...
s u m m a r y This paper compares the water budgets of two adjacent micro-catchments covered by mature (MAT) and 20-year-old secondary (SEC) lower montane cloud forests, respectively, in central Veracruz, Mexico over a 2-year period. Rainfall (P) and streamflow (Q) were measured continuously, whereas dry canopy evap-oration (transpiration E t), wet...
The La Antigua river upper watershed (1,325 km2), located on the eastern slopes of the Cofre de Perote-Pico de Orizaba volcano (central Veracruz, Mexico), is a region of
high biodiversity and great hydrological importance. The watershed plays a key role supplying water to main urban areas, such
as the capital of Veracruz (Xalapa) and Coatepec, and...
Within the framework of a larger project studying the hydrological impacts of converting tropical montane cloud forest to pasture in the Tilarán range of northern Costa Rica, physical and hydraulic properties of various volcanic soils were compared in two small watersheds covered with mature lower montane cloud forest and pasture, respectively. In...
Fog and wind-driven rain (WDR) are difficult to measure separately and reported measurements of “fog” often represent a combination of fog and WDR. In this chapter the term “horizontal precipitation” (HP) is used instead. Understanding of “typical” amounts of HP intercepted by different types of cloud forest is hampered by a lack of comparative inf...
Fog deposition, precipitation, throughfall and stemflow were measured in a windward tropical montane cloud forest near Monteverde, Costa Rica, for a 65-day period during the dry season of 2003. Net fog deposition was measured directly using the eddy covariance (EC) method and it amounted to 1·2 ± 0·1 mm day−1 (mean ± standard error). Fog water depo...
Understanding of the ‘typical’ amounts of fog intercepted by different types of cloud forests is hampered by a lack of comparative information on local fog climatology. Usually some kind of ‘fog gauge’ is used to characterize fog occurrence and amounts. Moreover, wind-driven fog and precipitation are difficult to measure separately and reported mea...
Over small-scale topography in windy areas, precipitation tends to be redistributed by wind through the modification of precipitation inclination. The latter is often derived from wind speed and conventional rain gauge records by application of relations—derived mainly for convective rainfall conditions—between (1) precipitation intensity and drop...
Epiphytic vascular plants and bryophytes constitute an important component of cloud forest canopies. Because of their different characteristics compared with leaves and other tree structural elements, epiphytes can be expected to behave differently in terms of their ability to intercept and store rain and cloud water, whereas losses through evapora...
Fog deposition, precipitation, throughfall, and stemflow were measured in a windward tropical montane cloud forest near Monteverde, Costa Rica, for a 65-day period during the dry season of 2003. Net fog deposition was measured directly with the eddy covariance method and amounted to 1.2 ± 0.1 mm day-1 (mean ± standard error). Fog water deposition w...
Aim Humid tropical alpine environments are crucial ecosystems that sustain biodiversity, biological processes, carbon storage and surface water provision. They are identified as one of the terrestrial ecosystems most vulnerable to global environmental change. Despite their vulnerability, and the importance for regional biodiversity conservation and...
Fog deposition, precipitation, throughfall and stemflow were measured in a windward tropical montane cloud forest near Monteverde, Costa Rica, for a 65-day period during the dry season of 2003. Net fog deposition was measured directly using the eddy covariance (EC) method and it amounted to 1.2 ± 0.1 mm/day (mean ± standard error). Fog water deposi...
The Páramo ecosystem is a high-altitude (2800 - 4500 masl), natural ecosystems which comprises approximately 42000 km2, extending across the Andes from north of Peru, Ecuador, Colombia and western part of Venezuela. Andean páramos are widely considered to be prime suppliers of large volumes of high-quality water for large cities and for hydropower...
The hydrological importance of tropical montane cloud forests is recognized increasingly, mostly with respect to the additional water inputs provided by the capture of fog by the forest canopy compared to a non-forested situation (e.g. pasture) in the same environmental setting. The deposition of fog (interception) consists of two components, viz....
Fog and wind-driven rain (WP) are difficult to measure separately and as such most measurements of fog reported upon are measurements of both fog and WP combined. This is called horizontal precipitation (HP) in this paper. Understanding of 'typical' amounts of HP intercepted by different types of tropical montane cloud forest is hampered by a lack...
During the last decade several initiatives aiming at conserving and protecting the water provision of Andean ecosystems have started. However, their implementation has faced a number of limitations on the technical side, mainly due to the lack of knowledge of hydrological processes and Andean-specific developed and tested hydrological models for sc...
Risks of weather and (changing) climate in forestry are large and vary considerably in time and space. Among them, most observed risks relate to altitudinal shifts (Peters and Darling 1985; Kariuki et al. 1997; Scheffer et al. 2001; Zhao et al. 2005), changes in productivity, standing biomass and species composition and fire damages (Dixon et al. 1...
Precipitation is the most fundamental input of water for terrestrial ecosystems. Most precipitation inputs are vertical, via rain, but can be horizontal, via wind-driven rain and snow, or, in some ecosystems such as tropical montane cloud forests (TMCFs), via fog interception. Fog interception can be particularly important in ecosystems where fog i...
Epiphytic biomass, canopy humus and associated canopy water storage capacity are known to vary greatly between old-growth
tropical montane cloud forests but for regenerating forests such data are virtually absent. The present study was conducted
in an old-growth cloud forest and in a 30-year-old secondary forest (SF) on wind-exposed slopes in the C...
This study, carried out in the Páramo de Guerrero (Cundinamarca, Colombia) aimed at quantifying the fog interception capacity by the páramo vegetation (Weinmannia spp, Gaiadendron punctatum, Espeletia grandiflora and Holcus lanatus)¿ and to make a continuous monitoring of the soil surface water content, in order to determine the net inputs to the e...
This Technical Report describes the hydrometeorological, hydrological and soil physical field measurement techniques that were employed to quantify the water budget and hydrological functioning of windward montane cloud forested and pasture catchments near San Gerardo, NW Costa Rica in the DFID-FRP R7991 project.
Declining dry season flows in Central America constitute a problem for rural and urban water
supplies and may in due course hamper agricultural production and hydropower generation. This
project aimed to quantify the impact of cloud forest conversion to pasture on streamflow in northern
Costa Rica using hydrological process research and modellin...
This chapter discusses the contribution that fields such as experimental design and human-computer interaction can make to geovisualization. In particular, it shows the ways multiple techniques can be combined not only to evaluate a system' s effectiveness, but also to address the complex issue of task definition in geovisualization research. A met...
The contribution of throughfall and stemflow as pathways for solute inputs into the forest floor in four mature forests in northwest Amazonia was investigated. Total solute inputs, resulting from the changes of atmospheric deposition after rainfall passes through the forest canopy, are presented in the form of throughfall and stemflow nutrient inpu...
Samples of the fraction of net rainfall passing through the forest floor collected at monthly intervals in four pristine forests in Colombian Amazonia, during the period between 1995–1997 were analysed for solute concentrations to estimate the element fluxes from the forest floor into the mineral soil and root nutrient uptake from these forest floo...
A common feature in the undisturbed forest ecosystems in the Middle Caquetá (Colombian Amazonia) is the presence of a thick litter layer with abundant fine roots over mineral soils which are highly weathered and very low in available nutrients. In these situations, the litter layer or the forest floor (FF) may play an important role in the forest w...
The partitioning of gross rainfall into throughfall, stemflow and evaporation of intercepted rainfall was studied in four forest ecosystems in the Middle Caquetá, Colombian Amazonia. Data on climate was collected automatically on an hourly basis during a five-year period. Weekly measurements of rainfall, throughfall and stemflow were carried out du...
The proliferation of large yet finely granulated data sets has created the need to develop new and sophisticated methods of analysis in order to reveal the information locked within them. Visualisation plays a major role in this process, and enables the creation of information products that communicate the outcome of digital representation. However...
Public Participation GIS (PPGIS) is a field of research
that, among other things, focuses on the use of GIS by nonexperts
and occasional users. These users tend to have a diverse
range of computer literacy, world views, cultural backgrounds and
knowledge. These aspects require that the systems used within
PPGIS are accessible and easy to use. Usabi...
