Browsing by Author "Marín Molina, Franklin Geovanny"

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Changes in soil hydro-physical properties and SOM due to pine afforestation and grazing in Andean environments cannot be generalized
(2018) Marín Molina, Franklin Geovanny; Quiroz Dahik, Carlos Alberto; Mosquera Rojas, Giovanny Mauricio; Feyen Null, Jan Null; Cisneros Espinoza, Pedro José Francisco; Crespo Sánchez, Patricio Javier
Andean ecosystems provide important ecosystem services including streamflow regulation and carbon sequestration, services that are controlled by the water retention properties of the soils. Even though these soils have been historically altered by pine afforestation and grazing, little research has been dedicated to the assessment of such impacts at local or regional scales. To partially fill this knowledge gap, we present an evaluation of the impacts of pine plantations and grazing on the soil hydro-physical properties and soil organic matter (SOM) of high montane forests and paramo in southern Ecuador, at elevations varying between 2705 and 3766 m a.s.l. In total, seven study sites were selected and each one was parceled into undisturbed and altered plots with pine plantation and grazing. Soil properties were characterized at two depths, 0–10 and 10–25 cm, and differences in soil parameters between undisturbed and disturbed plots were analyzed versus factors such as ecosystem type, sampling depth, soil type, elevation, and past/present land management. The main soil properties affected by land use change are the saturated hydraulic conductivity (Ksat), the water retention capacity (pF 0 to 2.52), and SOM. The impacts of pine afforestation are dependent on sampling depth, ecosystem type, plantation characteristics, and previous land use, while the impacts of grazing are primarily dependent on sampling depth and land use management (grazing intensity and tilling activities). The site-specific nature of the found relations suggests that extension of findings in response to changes in land use in montane Andean ecosystems is risky; therefore, future evaluations of the impact of land use change on soil parameters should take into consideration that responses are or can be site specific.
Comparison of natural regeneration in natural grassland and pine plantations across an elevational gradient in the páramo ecosystem of southern Ecuador
(2019) Quiroz Dahik, Carlos Alberto; Marín Molina, Franklin Geovanny; Arias Chumbi, Ruth Eulalia; Crespo Sánchez, Patricio Javier; Weber, Michael; Palomeque Pesántez, Fanny Ximena
During the 1980s, reforestation programs using exotic species (Pinus spp.) were established in the páramo ecosystem of Ecuador. The aims of this study were: (1) to compare the natural regeneration between pine plantations (Pi) and natural grassland (NG) across an elevational gradient and (2) to identify the attributes of Pi and soil properties that were influencing herbaceous and woody plant composition and their plant cover. In total, six independent Pinus patula (Schltdl. & Cham. plantations (two per each elevation) were selected and distributed in an elevational range (3200–3400, 3400–3600, 3600–3800 m a.s.l.). Adjacent to Pi, plots in NG were established for recording natural regeneration. Both, namely the attributes and the soil samples, were measured in Pi. The results showed that natural regeneration differs significantly between both types of vegetation. As expected, NG holds more plant diversity than Pi; the elevational range showed a clear tendency that there was more herbaceous richness when elevation range increases, while the opposite was found for woody species. Moreover, attributes of Pi influenced herbaceous and woody vegetation, when saturated hydraulic conductivity (Ksat) in the soil, basal area (BA) and canopy density (CD) increased, herbaceous species richness and its cover decreseased; and when Ksat and the acidity in the soil increased, woody plants richness and its cover decreased. The plantations have facilitated the establishment of shade tolerant species. More studies are needed to evaluate if removal with adequate management of pine plantations can improve the restoration and conservation of the native vegetation of the páramo ecosystem.
Efectos de la posición fisiográfica en las propiedades hidrofísicas de los suelos de páramo de la microcuenca del Río Zhurucay
(2014) Aucapiña Chaca, Gabriel Adolfo; Marín Molina, Franklin Geovanny; Crespo Sánchez, Patricio Javier
The aim of this investigation is identify the effects of the physiographic position on the hydrophysical properties of the soil moorland of the watershed of the Zhurucay river, it is located in the area of Quimsacocha and soils that jut are Andosols and Histosols. In the upper part of the watershed of the Zhurucay were delineated 3 transects and were described 45 profiles taking into account the physiographic position. Furthermore in each location were took disturbed and undisturbed samples. A property that was analyzed on field was the saturated hydraulic conductivity across of the auger hole method and inversed auger hole. In laboratory by means of the disturbed and undisturbed samples were determined the moisture contents in 6 points pF. Furthermore, by means of the moisture contents were determined the gravitational water contents and available water. Bulk density was determined with undisturbed samples. Due to the importance of organic matter of the soils was determined the content of organic matter with ignition method By means of the no parametric tests were compared the depth of the soils and hydrophysical properties of the surface horizons of 6 physiographic positions that were identified. The results showed that the physiographic position affect significantly in the depth of the soils where the valley bottom there are of great depth soils. Also in the surface horizons, majority of hydrophysical properties and organic matter contents showed to be affected by physiographic positions where the surface horizons of valley bottom showed differences with middle slope, upper slope and summit. Finally, the relations between hydrophysical properties as also with organic matter were studied.
Evaporation dynamics and partitioning in Andean tussock grasslands
(Ed, 2022) Célleri Alvear, Rolando Enrique; Ochoa Sánchez, Ana Elizabeth; Crespo Sánchez, Patricio Javier; Carrillo Rojas, Galo José; Sucozhañay Calle, Adrián Esteban; Marín Molina, Franklin Geovanny; Ochoa Sánchez, Ana Elizabeth
The paramo biome, located above 3300 m a.s.l. and covered mainly by tussock grasslands, provides ecosystem services for Andean cities, especially water resources used for drinking water, agriculture, hydropower generation and sustaining aquatic ecosystems. Even though research about the main components of the water cycle has increased substantially in the last decade, evaporation has remained unknown. In this study, we quantified for the first time daily, monthly and annual evaporation, its components (i.e. interception and transpiration) at event scale and its climatic drivers at a representative páramo catchment in Southern Ecuador (Figure 1). We used the eddy-covariance method to quantify evaporation. We additionally compared those measurements with lysimeters, water balance, energy balance, hydrological models (HBV-light and PDM) and the calibration of the Penman-Monteith equation in order to find easier and cheaper alternatives for estimating evaporation at the páramo
Frontiers in páramo water resources research: A multidisciplinary assessment
(2023) Marín Molina, Franklin Geovanny; Crespo Sánchez, Patricio Javier
Interdisciplinary knowledge is necessary to achieve sustainable management of natural resources. However, research is still often developed in an exclusively disciplinary manner, hampering the capacity to holistically address environmental issues. This study focuses on páramo, a group of high-elevation ecosystems situated around ∼3000 to ∼5000 m a.s.l. in the Andes from western Venezuela and northern Colombia through Ecuador down to northern Peru, and in the highlands of Panama and Costa Rica in Central America. Páramo is a social-ecological system that has been inhabited and shaped by human activity since ∼10,000 years BP. This system is highly valued for the water-related ecosystem services provided to millions of people because it forms the headwaters of major rivers in the Andean-Amazon region, including the Amazon River. We present a multidisciplinary assessment of peer-reviewed research on the abiotic (physical and chemical), biotic (ecological and ecophysiological), and social-political aspects and elements of páramo water resources. A total of 147 publications were evaluated through a systematic literature review process. We found that thematically 58, 19, and 23 % of the analyzed studies are related to the abiotic, biotic, and social-political aspects of páramo water resources, respectively. Geographically, most publications were developed in Ecuador (71 % of the synthesized publications). From 2010 onwards, the understanding of hydrological processes including precipitation and fog dynamics, evapotranspiration, soil water transport, and runoff generation improved, particularly for the humid páramo of southern Ecuador. Investigations on the chemical quality of water generated by páramo are rare, providing little empirical support to the widespread belief that páramo environments generate water of high quality. Most ecological studies examined the coupling between páramo terrestrial and aquatic environments, but few directly assessed in-stream metabolic and nutrient cycling processes. Studies focused on the connection between ecophysiological and ecohydrological processes influencing páramo water balance are still scarce and mainly related to the dominant vegetation in the Andean páramo, i.e., tussock grass (pajonal). Social-political studies addressed páramo governance and the implementation and significance of water funds and payment for hydrological services. Studies directly addressing water use, access, and governance in páramo communities remain limited. Importantly, we found only a few interdisciplinary studies combining methodologies from at least two disciplines of different nature despite their value in supporting decision-making. We expect this multidisciplinary synthesis to become a milestone to foster interdisciplinary and transdisciplinary dialogue among individuals and entities involved in and committed to the sustainable management of páramo natural resources. Finally, we also highlight key frontiers in páramo water resources research, which in our view need to be addressed in the coming years/decades to achieve this goal
Impactos de las plantaciones de pino y pastoreo sobre las propiedades hidrofísicas y SOM de los suelos alto andinos del sur del Ecuador
(2018-11-06) Marín Molina, Franklin Geovanny; Crespo Sánchez, Patricio Javier
In South America, high Andean ecosystems such as high montane forests and the páramos provide important ecosystem services; they are associated with high water regulation capacity and water retention properties of the soils. However, these soils have been altered by the establishment of pine plantations and grazing. The objective of this study is to evaluate the impacts of pine plantations and grazing on the hydro-physical properties and on the soils’ organic matter content (SOM) in southern Ecuador (2640 to 3758 m a.s.l.). In order to achieve this, seven study sites were selected and each one was parceled up into natural undisturbed plots, pine plantations, and grazing. All characteristics were considered at two different depths (0 - 10 cm, and 10 - 25 cm) in each plot. The results showed that the pine plantations and grazing sites in high Andean ecosystems produce changes (increments or reductions) mainly on the saturated hydraulic conductivity (Ksat), on the water retention capacity at pF 0 to 2.52, and on the SOM content; however, their impacts could not be generalized. The impacts of pine plantations were dependent on sampling depth, ecosystem type, plantation characteristics, and previous soil use. While the impacts of grazing are dependent on sampling depth, and soil management (grazing intensity and tilling activities). These relationships imply difficulties when evaluating impacts, and therefore, it is necessary to avoid generalizing the impacts on high Andean ecosystems at the regional scale.
Progress in understanding the hydrology of high-elevation andean grasslands under changing land use
(2022) Mosquera Rojas, Giovanny Mauricio; Crespo Sánchez, Patricio Javier; Román Dañobeytia, Francisco; Ochoa Tocachi, Boris Fernando; Bonnesoeur, Vivien; Stern, Margaret; Marín Molina, Franklin Geovanny
High-elevation grasslands worldwide provide essential hydrological services including water provision, flow regulation, and erosion control. Despite their importance, hydrological research of grasslands in montane regions is usually scarce and disperse, limiting the capacity to improve water resource management. We present a systematic literature review of the hydrological function of high Andean grasslands under conserved, degraded, and restored conditions in ecosystems situated above the tree line in the tropical Andes (paramos, punas, and jalcas). Most hydrological research on these grasslands has been developed in paramos (92%), especially in Ecuador, while research in punas is scarce (6%) despite being the largest grassland extent in the region. For paramos, published literature highlights the importance of conserving grasslands to facilitate water infiltration to soils, which in turn reduces erosive processes. Water-vegetation relations for conserved paramos are well understood, indicating that about 50% of water inputs return to the atmosphere via evapotranspiration, but knowledge about hydrological functions of conserved punas and jalcas is virtually non-existent. Under changing land use, afforestation of grassland ecosystems with exotic tree species, especially pines, reduces soil water storage as well as water yield and flow regulation capacity. Impacts of grazing and agriculture on the hydrological function of paramo grasslands strongly depend on historical land management and current land use practices and are not generalizable. Short-term restoration studies indicate that more than two years are necessary to recover the hydrological function of degraded grasslands, therefore medium and long-term studies are required to determine efficient restoration periods. These knowledge gaps limit the ability to extrapolate and regionalize findings. Future directions aimed to fill them are proposed, and methods successfully used to investigate the hydrology of high Andean grasslands are highlighted. This research not only enlightens what is known about the hydrology of high Andean grasslands, but also seeks to guide future hydrological evaluations to fill identified geographical and topical knowledge gaps precluding improved management of water resources in the tropical Andes. (c) 2021 Elsevier B.V. All rights reserved.
Respuesta de semillas de tres especies nativas altoandinas a diferentes condiciones de almacenamiento
(2019) Patiño Uyaguari, Claudia Guicelly; Jímenez Sánchez, Janeth Jazmin; Marín Molina, Franklin Geovanny; Palomeque Pesántez, Fanny Ximena
To ensure the germination capability and viability of native tree species it is important to know the optimum conditions for seed storage in the long term. In response to this, we investigated the effect of seed storage on the germination, viability,and velocity of germination (VG) of Vallea stipularis, Hedyosmum luteyniiand Oreopanax avicenniifolius. The seeds were collected in Llaviucu and Mazan forests in Cajas National Park and exposed to different treatments of seed storage: three levels of seed moisture content (initial, medium and low), two levels of temperature (10oC and room temperature) and three periods of storage (3, 6, and 12 months). The research revealed that seeds of V. stipularisstored at 10oC for 12 months had the lowest germination values, even null percentages; the more the seed viability and VG decreased when the time of seed storage increased. The seeds of H.luteynii showed high germination and viability up to 12 months of storage at 10oC, however, its germination was later and little synchronized. The room temperature did not work well for germination and VG for both these species, although, H.luteynii maintained its viability intact up to the last period of evaluation. O. avicenniifolius maintained at 10oC and room temperature its germination capacity up to 12 months but with a lower percentage. The knowledge generated contributes to better seed management in ex situ conservation programs and plant propagation for restoration.
Unravelling evapotranspiration controls and components in tropical Andean tussock grasslands
(2020) Ochoa Sánchez, Ana Elizabeth; Crespo Sánchez, Patricio Javier; Carrillo Rojas, Galo José; Marín Molina, Franklin Geovanny; Célleri Alvear, Rolando Enrique
The study of the environmental factors that control evapotranspiration and the components of evapotranspiration leads to a better understanding of the actual evapotranspiration (ET) process that links the functioning of the soil, water and atmosphere. It also improves local, regional and global ET modelling. Globally, few studies so far focussed on the controls and components of ET in alpine grasslands, especially in mountainous sites such as the tussock grasslands located in the páramo biome (above 3300 m a.s.l.). The páramo occupies 35 000 km2 and provides water resources for many cities in the Andes. In this article, we unveiled the controls on ET and provided the first insights on the contribution of transpiration to ET. We found that the wet páramo is an energy-limited region and net radiation (Rn) is primarily controlling ET. ET was on average 1.7 mm/day. The monthly average evaporative fraction (ET/Rn) was 0.47 and it remained similar for wet and dry periods. The secondary controls on ET were wind speed, aerodynamic resistance and surface resistance that appeared more important for dry periods, where significantly higher ET rates were found (20% increase). During dry events, transpiration was on average 1.5 mm/day (range 0.7–2.7 mm/day), similar to other tussock grasslands in New Zealand (range 0.6–3.3 mm/day). Evidence showed interception contributes more to ET than transpiration. This study sets a precedent towards a better understanding of the evapotranspiration process and will ultimately lead to a better land-atmosphere fluxes modelling in the tropics. © 2020 John Wiley & Sons Ltd