Browsing by Author "Villamagua Vergara, Gabriela Carolina"

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Análisis multitemporal del cambio de cobertura vegetal en el área de conservación La Capilla, Cañar
(Universidad de Cuenca, 2024-08-08) Vega Arteaga, Dick Miguel; Villamagua Vergara, Gabriela Carolina
A multitemporal analysis of vegetation cover change in the La Capilla conservation area, in the Cañar canton, during the period from 1986 to 2021 was carried out. Using Landsat satellite images and by generating spectral signatures, a supervised classification of nine categories of occupation was carried out. The objective was to identify significant changes in the different vegetation covers of the study area over 35 years. A table of evolution and annual rate of change of the area was applied together with a cross-tabulation matrix analysis. In general terms, native forest cover increased considerably during the periods from 2001 to 2021. This increase was temporarily affected by the development of pine plantation forest cover between 1996 and 2001. After this period, an increasing trend of native forest recovery was observed. On the other hand, shrub vegetation showed a decreasing trend until 2016, recovering slightly in 2021. The main patterns of change within the study area are related to accidental fires and soil degradation, the latter conditioned by past cattle ranching. The strategy of earmarking the area for conservation has generally worked. However, more active restoration measures and integration of more sustainable productive measures are needed due to the strong anthropic pressure on the area's borders. These findings highlight the importance of monitoring and conserving vegetation cover in La Capilla to mitigate environmental impacts and guarantee the provision of ecosystem services
Detección temprana de antracnosis foliar en plantas de fréjol (Phaseolus vulgaris) mediante análisis espectral visible
(Universidad de Cuenca, 2025-08-05) Guallpa Duy, Steven Alexander; Villamagua Vergara, Gabriela Carolina
Plant diseases cause significant economic losses in agriculture. In Ecuador, the common bean (Phaseolus vulgaris) is a key crop for food security and sustainable production. However, it faces threats such as foliar anthracnose, caused by Colletotrichum lindemuthianum, which can reduce yields by up to 95% in humid, mountainous regions like Azuay. Early detection of this disease is essential for implementing effective control measures and minimizing production losses. Although various diagnostic methods exist, many are costly or slow, limiting their adoption in resource-constrained settings. This study aimed to evaluate the application of visible spectral analysis for the early detection of foliar anthracnose in bean plants using RGB images captured with mobile devices (Samsung A11 and Tecno Spark 20), based on three vegetation indices: MPRI, MGRVI, and VARI. A total of 25 inoculated leaflets and 25 control (non-inoculated) leaflets were photographed over five days post-inoculation. The first non-visible spectral symptoms appeared 72 hours after inoculation, increasing progressively in the following days, unlike the control group, which showed no signs of disease. No significant differences were found among the indices used, but there were differences between the devices: the Samsung A11 stood out for a higher number of detections, while the Tecno Spark 20 excelled in quantifying diseased area in the later stages of sampling. Additionally, the underside of the leaf showed greater sensitivity to symptom detection than the upper side. These findings support the use of visible spectral analysis with conventional cameras as an accessible and efficient tool for the development of automated early detection systems for fungal diseases in food crops.