En los Andes occidentales del sur del Ecuador existen remanentes de bosques tropicales montanos andinos, BTMA, que merecen ser estudiados ecológicamente para valorarlos y conservarlos. El objetivo de esta investigación fue describir la diferencia de parámetros taxonómicos y funcionales de la vegetación arbórea y, además, explicar su relación con variables predictoras. Se utilizaron predictoras de clima, de suelos y una autocorrelación espacial para explicar las diferencias en la composición, diversidad, densidad arbórea, biomasa y rasgos funcionales entre dos tipos de BTMA: bosque siempreverde montano (BSM) y bosque siempreverde montano alto (BSMA). La diferencia en la composición de especies fue descrita con análisis de similitudes y escalamiento multidimensional no métrico. Las diferencias en la diversidad, densidad, biomasa y rasgos funcionales se evaluaron mediante pruebas de medias con t de Student. La relación entre la composición de especies y variables predictoras fue analizada con partición de varianza, y la densidad arbórea, biomasa aérea y rasgos funcionales, con modelos lineales generalizados. La composición de especies fue diferente entre los dos tipos de bosques. Estas diferencias fueron explicadas por el clima y la autocorrelación espacial. La densidad arbórea y la biomasa aérea fueron superiores en el BSMA. El promedio ponderado del área foliar (AF) fue superior en el BSM, y el área foliar específica (AFE) fue mayor en el BSMA. La composición de especies fue explicada por la precipitación media anual (PMA) y la temperatura media anual (TMA); la densidad arbórea, por la TMA, la densidad aparente (DA) y la materia orgánica; la biomasa arbórea aérea, por la TMA; el AF, por la TMA y la DA, y el AFE, por la PMA. Se concluye que los parámetros de la vegetación varían en gradientes altitudinales pequeños, donde existe heterogeneidad ambiental condicionada por el clima y ciertas variables de los suelos.

The NDVI is typically associated with medium-resolution images, e.g., Landsat imagery, and has often been linked to various agricultural parameters, except agricultural energy inputs. Thus, our objective was to analyze the performance of the NDVI associated with Landsat images to monitor both the evolution and impact of energy inputs on the spectral activity in some rural mountain crops. To do so, we studied energy inputs in three scenarios in the Ecuadorian Andes: high-mountain agroforestry systems (HAFSs), short-cycle production systems (SHCs), and low-mountain agroforestry systems (LAFSs). In 2022, information on energy inputs was collected for 415 systems (through field surveys). Using Google Earth Engine, we analyzed NDVI data associated with Landsat images between 2012 and 2023. Statistical analysis demonstrated significant positive correlations between energy inputs and the NDVI. As a novelty, this result means that energy inputs influence crops’ spectral activity. Furthermore, we demonstrated a historical enhancement of energy inputs across the inputs at the Landsat image scale. Therefore, further studies are needed to improve the resolution of this approach, for example, by integrating higher-resolution images to assess a more accurate NDVI response.

Background. Vegetable crops in Ecuador are produced primarily by smallholders in the Andes. Cuenca is an intermediate city in Southern Ecuador whose demand of fresh vegetables is supplied mostly by small farms located < 60 Km from the city. Objective. The objective of this study was to characterize smallholder vegetable farms located on the outskirts of Cuenca using input/output energy balances. Methodology. One hundred and four vegetable farms were visited during the first semester of 2016. Farmers were interviewed using a semi-structured questionnaire about the inputs used by them for crop production and the outputs of their crops. Results. Most of the farms (83) produced negative energy balances with energy efficiencies ranging from 0.16 to 0.97 whereas farms with positive energy balances had efficiencies ranging from 1.03 to 1.97. The largest energy input in most farms was from organic fertilizers, followed by the planting material and direct energy use for pumping and other farm activities. A positive significant correlation was detected between farm size and energy efficiency. Implications. Our results reveal opportunities to improve the functioning of these farming systems and the need to take into account efficiency considerations in the design of technological and policy interventions oriented to improve the sustainability of these systems. Conclusions. Most smallholder vegetable farms in periurban Cuenca operate producing negative energy balances. Organic fertilizers and direct energy are the largest energy inputs used in these farms. Potential energy economies of scale were detected both in energy efficient and energy inefficient farms.

The Andean region of southern Ecuador with its climatic and geographical heterogeneity has given rise to different production systems: from intensive agriculture in the lowlands to subsistence and agroforestry systems in the highlands. With a marked structural division between intensive agriculture and biodiverse agriculture. Social dynamics such as migration have an impact, aggravating rural depopulation and food insecurity. In this context, Andean agrobiodiversity represents a key strategy to cope with climate change and promote sustainable agricultural systems. The objectives of this study were: i) To analyse the agro-ecological characteristics (slope, elevation, area, floristic diversity and chlorophyll concentration) of different agricultural production systems in the southern Andes of Ecuador. ii) To evaluate the consumption, efficiency and sustainability of energy use in different Andean agricultural production systems. iii)Analyse the link between agricultural energy inputs and vegetation condition through the NDVI index, using Landsat satellite images in Andean production scenarios in Ecuador between 2012 and 2023. iiii) Develop a theoretical model to estimate the carbon stock in biomass and soil, as well as the CO emissions derived from agricultural practices in different Andean production scenarios. High mountain agroforestry systems (HAFS), short-cycle cropping (SHC) and greenhouse systems (GHSE) were found on sloping land, which makes them vulnerable to erosion and requires the implementation of specialised agricultural practices. The low mountain agroforestry systems (LAFS) are in flat areas, which favours mechanisation and extensive crop management. The values obtained for the Margalef, Simpson and Shannon-Wiener indices confirmed the greater structural and functional heterogeneity of the HAFS. Despite the high species similarity between the systems, abundance was significantly lower in LAFS. Chlorophyll content (Chl), varied significantly between species and systems, with higher values in LAFS, due to both its favourable climate and high fertiliser use. In terms of total energy consumption, the GHSE and SHC systems were the most demanding, with values of 46.38 GJ ha- and 44.40 GJ ha-, respectively. In contrast, HAFS and LAFS reported significantly lower consumptions (11.98 and 10.49 GJ ha-). Fertiliser was the main source of energy consumption (31.8%), followed by labour (30%) and plant management (25.7%). All systems had a high dependence on non-renewable energy (mean 0.62) and low energy autonomy (0.12), with GHSE and SHC being the most dependent and HAFS and LAFS the most sustainable. NDVI analysis using Landsat images (TOA, SR and C) proved to be effective for our scenarios. Landsat-SR images yielded the highest Max_NDVI values: up to 0.92 in LAFS, 0.80 in SHC and lower and non-significant values in HAFS. A moderate positive correlation (r = 0.36) was observed between energy efficiency and NDVI. C stock estimation showed that both HAFS and LAFS accumulate similar amounts of carbon in aboveground and root biomass (20.34 and 17.51 Mg C ha-, respectively), with no significant statistical differences. However, in soil carbon, SHC stood out with the highest values (16.54 Mg ha-), followed by HAFS (15.37 Mg ha-) and LAFS (13.95 Mg ha-). GHSE recorded the lowest value (9.21 Mg ha-). In terms of CO emissions, the GHSE system had the highest total emissions (17.41 Mg CO ha-), followed by SHC (7.63 Mg CO ha-). In contrast, the HAFS and LAFS systems had the lowest emissions (1.37 and 0.30 Mg CO ha-). RESUMEN La región andina del sur del Ecuador con una heterogeneidad climática y geográfica ha dado lugar a distintos sistemas de producción: desde una agricultura intensiva en las zonas bajas hasta sistemas de subsistencia y agroforestales en las zonas altas. Con una marcada división estructural entre la agricultura intensiva y la agricultura biodiversa. Las dinámicas sociales, como la migración afectan, agravando el despoblamiento rural y la inseguridad alimentaria. En este contexto, la agrobiodiversidad andina representa una estrategia clave para enfrentar el cambio climático y promover sistemas agrícolas sostenibles. Los objetivos de este estudio fueron: i) Analizar las características agroecológicas (pendiente, elevación, área, diversidad florística y concentración de clorofila) de diferentes sistemas de producción agrícola en los Andes del sur de Ecuador. ii)Evaluar el consumo, eficiencia y sostenibilidad del uso de energía en diferentes sistemas de producción agrícola andinos. iii)Analizar el vínculo entre los insumos energéticos agrícolas y el estado de la vegetación a través del índice NDVI, utilizando imágenes satelitales Landsat en escenarios productivos andinos del Ecuador entre 2012 y 2023. iiii) Desarrollar un modelo teórico para estimar el stock de carbono en biomasa y suelo, así como las emisiones de CO derivadas de las prácticas agrícolas en distintos escenarios de producción andina. Los sistemas agroforestales de alta montaña (HAFS), los de cultivos de ciclo corto (SHC) y los sistemas bajo invernadero (GHSE), se encontraron en terrenos con pendiente, lo que los hace vulnerables a la erosión y demandan la implementación de prácticas agrícolas especializadas. Los sistemas agroforestales de baja montaña (LAFS) se ubican en zonas planas, lo que favorece la mecanización y el manejo extensivo de los cultivos. Los valores obtenidos en los índices Margalef, Simpson y Shannon-Wiener, confirmaron la mayor heterogeneidad estructural y funcional de los HAFS. A pesar de la alta similitud de especies entre los sistemas, la abundancia fue significativamente menor en los LAFS. El contenido de clorofila (Chl), varió significativamente entre especies y sistemas, con mayores...