Browsing by Author "Quiroz Dahik, Carlos Alberto"

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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.
Contrasting stakeholders perceptions of pine plantations in the páramo ecosystem of Ecuador
(2018) Quiroz Dahik, Carlos Alberto; Crespo Sánchez, Patricio Javier; Stimm, Bernd; Murtinho, Felipe
The páramo, a collection of Neotropical alpine ecosystems, plays a prominent role in ecosystem services (ESs), providing water supply and regulation, conservation of biodiversity, and carbon storage in soil. The establishment of pine plantations for carbon sequestration and wood production has recently raised questions concerning the possible impact on the páramo's ES. This study identifies the main stakeholders in this field and compares and contrasts their perceptions of the impact of pine plantations on the páramo's ES, because the disparity among stakeholders' perceptions must be addressed to achieve sustainable management. The data were gathered using 56 semi-structured interviews and were qualitatively analyzed. The results show that the main stakeholder groups (landowners, local government officials, foresters, and nature conservationists) acknowledge the important ES of the plantations. The perception of plantation impact varies among and within stakeholder groups, however, on specific functions, such as water provision, carbon storage, erosion prevention, and habitat function for wildlife and natural vegetation. Consideration and integration of these perceptions can help policymakers and organizations develop sustainable policies for the futuremanagement of the páramo ecosystem.