GC026-0010
Evaluating upslope vegetation migration in a tropical mountainous watershed

Tuesday, 8 December 2020
Poster
Leila Saberi1, Rachel McLaughlin2, G. H. Crystal Ng3, Daniel Stanton4, Veronica G. Minaya5, Jeff La Frenierre6, Carla P. Manciati5, Priscilla Muriel7 and Xavier Zapata-Rios8, (1)University of Minnesota Twin Cities, Department of Earth Sciences, Minneapolis, MN, United States, (2)University of Minnesota Twin Cities, Earth sciences, Minneapolis, MN, United States, (3)University of Minnesota, Twin Cities, Department of Earth Science, Minneapolis, MN, United States, (4)University of Minnesota, Twin Cities, Twin Cities, United States, (5)Escuela Politecnica Nacional, Quito, Ecuador, (6)Gustavus Adolphus College, Saint Peter, MN, United States, (7)Pontifical Catholic University of Ecuador, Quito, Ecuador, (8)Escuela Politécnica Nacional, Civil and Environmental Engineering, Quito, Ecuador
Abstract:
Climate models predict amplified warming in glacierized tropical mountains, 99% of which are located in the Andes. Temperature increases on mountain slopes expand the suitable elevations for plant growth, and the consequent upslope migration of plants increases water uptake and transpiration rates. This ecohydrological change exacerbates the impact of warming by reducing baseflow to streams, which in tropical glacierized mountains will compound with decreased meltwater contributions that will eventually occur as glaciers retreat. Historical observations have suggested that tropical Andean plants have migrated an average of 2.5 – 3.5 vertical meters upslope per year, presumably in response to a warmer temperature, but the accuracy of these estimates is debated, and questions persist about other physical and ecological factors influencing the migration. The uncertainties in the historical data used in previous studies, combined with recent land-use change and accelerated warming, require a more accurate evaluation of the response of vegetation to environmental changes. Here, we used a combination of satellite imagery, high-resolution orthophotos, and digital elevation models in order to evaluate tropical Andean plant migration and its driving factors. Specifically, we delineated new land-cover class boundaries and created an updated land-cover map, which characterizes the changes in plant species and distribution from 1978 to 2019 in a tropical glacierized mountainous watershed on Volcán Chimborazo, Ecuador. We implemented an object-based image analysis (OBIA) by employing eCognition software. The land-cover classification was validated using the ground truth data points collected during a 2019 field campaign. The results of this study will be incorporated in a physically based, fully-coupled land-surface, hydrologic model to further investigate the hydrologic response of the tropical glacierized watershed to changes in both glacier melt and vegetation.
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