ABSTRACT Desertification is the degradation process caused by climatic conditions and human activities that results in loss of soil productivity and decline in vegetation growth in the long term. Several indices related to vegetation, soil and climate are used to monitor desertification, but few studies explore qualitative and quantitative aspects of indices on desertification on spatial and hierarchical scale. This study aims to identify and measure indices related to increased risk of desertification on global, local and hierarchical scales using multinomial logistic regression models. Images from TM, ETM+ and OLI sensor from 1997 to 2018 in the end of dry and rainy seasons were used to quantify NDVI, TGSI, albedo, temperature, aridity index, evapotranspiration and precipitation on global spatial scale (Irauçuba Centro Norte) and local spatial scale (Miraíma, Canindé, Irauçuba and Santa Quitéria). GISD was calculated by geometric mean of weighted indices and segmented into 8 classes of susceptibility to desertification (hierarchical scale). The results showed that the best models were obtained on local scale and for the end of the rainy season. Temperature proved to be the most important variable for increased risk of desertification on global, local and hierarchical scales. Therefore, the increase in the risk of desertification in the studied areas is due to human activities of deforestation, overgrazing and fire. These factors contributed to reduction of vegetation cover and increase in temperature, changing the microclimatic, which led to decline in precipitation and worsening of desertification. term TM ETM 199 201 NDVI TGSI albedo temperature index Norte Miraíma, Miraíma (Miraíma Canindé Quitéria. Quitéria . Quitéria) scale) season Therefore deforestation fire microclimatic 19 20 1 2

Resumen Introducción. La erosión acelerada del suelo es una de las principales causas de la degradación del suelo, que se ve reforzada por las actividades humanas que reducen la cobertura del suelo y aumentan su densidad. Metodologia: Por lo tanto, el objetivo de este estudio es cuantificar y comparar las pérdidas de suelo por erosión, entre áreas con agricultura convencional y vegetación natural en el sitio Potós ubicado en la zona rural del municipio de Ubajara, Ceará, Brasil. Resultados. Para monitorear la erosión, se instalan nueve pines de erosión en cada tratamiento, distribuidos en forma triangular, en el sentido de la pendiente, entre las hileras de plantas. El monitoreo se realizará mensualmente durante los años 2020 y 2021. Las pérdidas mensuales varían entre 0 y 948,73 Mg ha-1 mes, siendo las mayores en los meses más lluviosos, registrándose las mayores pérdidas en el año de mayor precipitación total acumulada.

Abstract Introduction. Accelerated soil erosion is one of the major causes of land degradation, which is exacerbated by human activities that reduce soil cover and increase its density. Objective. This study aimed to quantify and compare the levels of soil erosion between areas with conventional agriculture and natural vegetation at the Potós site located in the rural area of the municipality of Ubajara, Ceará, Brazil. Methodology. To monitor erosion, nine erosion pins were installed in each treatment area, arranged in a triangular mesh pattern, in the direction of the slope and between the rows of plants. Monitoring will occur monthly during 2020 and 2021. Results. Monthly losses range from 0 to 948.73 Mg ha-1 month, with the highest losses occurring in the driest months. The greatest losses were recorded in the year with the highest total accumulated precipitation.

Resumo Introdução: A erosão acelerada do solo é uma das principais causas de sua degradação, sendo esta potencializada por atividades antrópicas que reduzem a cobertura do solo e aumentam sua densidade. Objetivo: Ante isso, com o presente estudo objetivou-se quantificar e comparar as perdas de solos por erosão, entre áreas com agricultura convencional e vegetação natural no sítio Potós localizado na zona rural do município de Ubajara, Ceará, Brasil. Metodologia: Para monitorar a erosão foram instalados nove pinos de erosão em cada tratamento, distribuídos em malha triangular, no sentido do declive e entre as fileiras de plantas. O monitoramento ocorreu mensalmente durante os anos de 2020 e 2021. Resultados: As perdas de solos mensais variaram entre 0 e 948,73 Mg ha-1 por mês e foram maiores nos meses mais chuvosos, sendo as maiores perdas registradas no ano com maior precipitação total acumulada.

Summary: The fraction of vegetation cover (FVC) and the Leaf Area Index (LAI) are biophysical variables closely related to the evapotranspiration rate of crops and their biomass production. Despite their importance, they are usually not measured directly due to their time-consuming and costly nature; however, they can be estimated on a large scale and near-real-time using spectral information captured in satellite images, although this requires prior validation at the field level. Simple linear regression models were developed and validated using 13 vegetation indices (VI) related to LAI and FCV in alfalfa (Medicago sativa). Three spectral information sources were used: (i) reflectance to derive the VI; (ii) digital photographs processed with the Canopeo application to estimate FVC; and (iii) direct LAI measurements using a ceptometer. Six field samples were taken between March and June, 2020 in four alfalfa plots located in Palmar de Bravo, Puebla, Mexico. To evaluate each VI, the determination coefficient (R2) and the root mean square error (RMSE) were used. We found that the most suitable VI for estimating FVC was the VIgreen (Green Vegetation Index, R2 =0.987 and RMSE = 0.093). For the LAI, the VI that performed best was the NDVI (Normalized Difference Vegetation Index, R2 = 0.935 and RMSE = 0.746). The results showed the suitability and practical utility of spectral information for estimating biophysical variables in alfalfa cultivation and their monitoring.

Resumen: La fracción de cobertura vegetal (FCV) y el índice de área foliar (IAF) son variables biofísicas relacionadas estrechamente con la tasa de evapotranspiración de los cultivos y su producción de biomasa. A pesar de su importancia, usualmente no se miden de manera directa debido al tiempo invertido y costo; sin embargo, se pueden estimar a gran escala y en tiempo casi real mediante información espectral captada en imágenes de satélite, pero esto requiere de su validación a nivel de campo. Se desarrollaron y validaron modelos de regresión lineal simple utilizando 13 índices de vegetación (IV) relacionados con el IAF y la FCV en alfalfa (Medicago sativa). Se usaron tres fuentes de información espectral: (i) La reflectancia para derivar los IV; (ii) fotografías digitales procesadas con Canopeo para estimar la FCV; y (iii) mediciones del IAF utilizando un ceptómetro. Se realizaron seis muestreos de campo entre marzo y junio de 2020, en cuatro parcelas de alfalfa situadas en Palmar de Bravo, Puebla, México. Para evaluar cada IV, se utilizó el coeficiente de determinación (R2) y la raíz del cuadrado medio del error (RCME). Se encontró que el IV más apropiado para estimar la FCV fue el VIgreen (Green Vegetation Index, R2 = 0.987 y RCME = 0.093). En el caso del IAF, el IV que presentó el mejor desempeño fue el Normalized Difference Vegetation Index (NDVI), R2 = 0.935 y RCME = 0.746). Los resultados mostraron la aptitud y utilidad práctica de la información espectral para estimar las variables biofísicas en el cultivo de alfalfa y su monitoreo.

ABSTRACT The contribution of plant residues throughout the sugarcane cycles favors the increase of organic matter and the activity of microorganisms in the soil, especially in the surface layers. Soil texture also has an important effect on ecological processes and soil quality. In this context, the objective of this study was to evaluate soil biological attributes in different sugarcane cultivation cycles under mechanized harvesting in an Oxisol in the Savanna region of Central Brazil. The study was conducted in commercial areas under sugarcane cultivation during the 2018/2019 season, which were considered homogeneous in terms of soil and climatic conditions, with the source of variation among the areas being the cultivation cycles (C1: one cultivation cycle; C3: three cultivation cycles; C7: seven cultivation cycles) and a savanna vegetation area selected as a reference. Microbiological variables were determined in two layers, 0-0.1 and 0.1-0.2 m. The variables related to microbial biomass and texture were subjected to principal component analysis. Areas with longer sugarcane cultivation cycles show higher proportion of microbial biomass carbon in the total organic carbon in subsurface layers (microbial quotient). The performance of the soil microbial community, as expressed by total organic carbon and microbial biomass nitrogen indicators, was associated with higher presence of clay and silt, i.e., soil particles smaller than 0.02 mm. quality context Brazil 20182019 2018 2019 2018/201 season conditions C1 C (C1 cycle C3 C7 reference 00.1 001 0 0.1 1 0-0. 0.10.2 0102 0.2 2 0.1-0. m analysis quotient. quotient . quotient) community indicators silt ie i e i.e. 002 02 0.0 mm 2018201 201 2018/20 (C 00 00. 01 0. 0-0 10 0.10. 010 0.1-0 i.e 201820 20 2018/2 0- 0.10 0.1- 20182 2018/

RESUMO O aporte de resíduos vegetais ao longo dos ciclos da cana-de-açúcar favorece o incremento de matéria orgânica e atividade de microrganismos no solo, especialmente nas camadas superficiais. A textura do solo também tem um efeito importante nos processos ecológicos e na qualidade do solo. Nesse sentido, o objetivo desta pesquisa foi avaliar atributos biológicos do solo em diferentes ciclos de cultivo de cana-de-açúcar sob colheita mecanizada, em um Latossolo da região de cerrado do Brasil Central. O estudo foi realizado em áreas comerciais de cultivo de cana-de-açúcar na safra 2018/2019, consideradas homogêneas em termos de condições edafoclimáticas, tendo como fonte de variação entre as áreas os ciclos de cultivo (C1: um ciclo de cultivo; C3: três ciclos de cultivo; C7: sete ciclos de cultivo) e uma área de vegetação de cerrado selecionada como referência. Foram determinadas variáveis microbiológicas nas camadas de 0-0,10 e 0,10-0,20 m. As variáveis relacionados à biomassa microbiana e textura foram submetidos à análise de componentes principais. Áreas com ciclos de cultivo de cana-de-açúcar mais longos apresentaram maior proporção de carbono da biomassa microbiana no carbono orgânico total nas camadas subterrâneas (quociente microbiano). O desempenho da comunidade microbiana do solo, expresso pelos indicadores carbono orgânico total e nitrogênio da biomassa microbiana foi associado à maior presença de argila e silte, ou seja, partículas de solo menores que 0,02 mm. canadeaçúcar cana açúcar superficiais sentido mecanizada Central 20182019 2018 2019 2018/2019 edafoclimáticas C1 C (C1 C3 C7 referência 00,10 0010 0 0,10 10 0-0,1 0,100,20 010020 0,20 20 0,10-0,2 m principais quociente microbiano. microbiano . microbiano) silte seja 002 02 0,0 mm 2018201 201 2018/201 (C 00 00,1 001 010 0,1 1 0-0, 100 0,100,2 01002 020 0,2 2 0,10-0, 0, 201820 2018/20 00, 01 0-0 0,100, 0100 0,10-0 20182 2018/2 0- 0,100 0,10- 2018/

Abstract Background: Maps of disturbed forests help to identify impacts on biodiversity and ecosystem services. Methods using only spectral data to detect disturbance at the regional level have limitations, but expert knowledge and fragmentation analysis can improve estimation. Questions: What is the distribution of disturbed forests in a region of high biodiversity, and which vegetation types and regions are most affected? Data description: SPOT 2015, Sentinel-2 satellite imagery from 2019. Vegetation data were collected at 653 sites. In addition, herbarium, agricultural census, and National Forest Inventory data were used. Study site and dates: Chiapas State, during 2018-2022. Methods: We elaborated a hybrid map of vegetation types, emphasizing identifying secondary forests. Also, we carried out a fragmentation analysis and calculated the woody biomass per forest type. Results: 40 % of the State still maintains tree cover, but only 18 % is undisturbed; most undisturbed forests are in three regions: Selva Lacandona, Sierra Madre, and Gulf Plain. Overall, the biomass of disturbed forests is significantly lower than that of their mature counterparts. Conclusions: In Chiapas, the distribution of forests with good conservation status is restricted; almost half of them are outside NPAs, so it is imperative to promote additional strategies for their conservation and management.

Resumen Antecedentes: Los mapas de bosques perturbados son útiles para identificar afectaciones sobre la biodiversidad y los servicios ecosistémicos. Los métodos que emplean únicamente datos espectrales para detectar las perturbaciones a nivel regional tienen limitaciones. El conocimiento de expertos y el análisis de fragmentación puede mejorar la estimación. Preguntas: ¿Cuál es la distribución de los bosques perturbados en una región de alta biodiversidad? ¿Qué tipos de vegetación y regiones son las más afectadas? Descripción de los datos: imágenes satelitales SPOT 2015, Sentinel-2 de 2019. Se colectó información de la vegetación en 653 sitios. Además, se usaron datos de herbario, censos agrícolas y del Inventario Nacional Forestal. Lugar y fecha del estudio: Estado de Chiapas, durante 2018-2022. Métodos: Se elaboró un mapa híbrido de los tipos de vegetación enfatizando la identificación de bosques secundarios, también se realizó un análisis de fragmentación y se calculó la biomasa leñosa por tipo de bosque. Resultados: El 40 % de la superficie del Estado mantiene una cobertura arbórea; pero solo en el 18 % no se aprecia perturbación; la mayor parte de los bosques no perturbados se encuentran en tres regiones: Selva Lacandona, Sierra Madre y Planicie del Golfo. En general la biomasa de los bosques perturbados es significativamente menor que la de su contraparte madura. Conclusiones: En Chiapas la distribución de los bosques en buen estado de conservación está restringida; casi la mitad de ellos se encuentran fuera de las ANP, por lo que es imperativo promover estrategias adicionales para su manejo y conservación.

RESUMEN El contenido de carbono orgánico (COS) del suelo bajo escenarios de cambio climático es esencial, especialmente en áreas de difícil acceso como los páramos tropicales de gran altitud. Este estudio tuvo como objetivo correlacionar los derivados del modelo de elevación digital (DEM), los índices espectrales Sentinel-1 y Sentinel-2 y los datos de WorldClim con el contenido de COS in situ en el páramo PNR-Cortadera (Boyacá, Colombia). A partir de 169 muestras de suelo recolectadas a dos profundidades (0-15 y 15-30 cm), se determinó el carbono orgánico mediante el método de Walkley-Black. Los contenidos de COS a 0-15 cm de profundidad variaron entre 25 a 200 t ha-1 y 33 a 466 t ha-1 a 15-30 cm. La altitud, la temperatura, el NDVI, el TWI0-15 cm, el MRVBF, el factor LS0-15 cm y la polarización de la banda VH mostraron las mejores correlaciones y el menor factor de inflación de la varianza. Los mayores contenidos de COS se ubican en la zona central y sur del páramo debido a la mayor altitud, precipitación y presencia de cobertura vegetal.

ABSTRACT The soil organic carbon (SOC) content under climate change scenarios is essential, especially in areas of difficult access such as the high-altitude Tropical paramos. This study aimed to correlate the digital elevation model (DEM) derivatives, spectral indices from Sentinel-1 and Sentinel-2, and WorldClim data with in situ SOC content in the PNR-Cortadera paramo (Boyaca, Colombia). Based on 169 soil samples collected at two depths (0-15 and 15-30 cm) organic carbon was determined using the Walkley-Black method. SOC contents ranged from 25 to 200 t HA-1 at 0-15 cm and from 33 to 466 t ha-1 at 15-30 cm. Altitude, temperature, NDVI, TWI0-15 cm, MRVBF, LS factor0-15 cm and VH band polarization showed the highest correlations and the lowest variance inflation factor. The highest SOC contents are located in the central and southern area of the paramo due to the higher altitude, greater precipitation and presence of vegetation cover.

Resumen Los bosques de galería son comunidades forestales que crecen a lo largo de los ríos y arroyos. Proporcionan numerosos servicios ecosistémicos, pero al igual que otras asociaciones vegetales están severamente amenazadas por actividades antrópicas como la agricultura. El objetivo del presente estudio fue conocer el estado actual de los bosques de galería del municipio Linares, Nuevo León por medio de un análisis multitemporal de cambio de uso de suelo y cobertura vegetal en cuatro periodos: 1995-2008, 2008-2014, 2014-2022 y 1995-2022. Para el análisis se utilizaron imágenes de alta resolución espacial de los satélites Airbus Defence and Space, GeoEye-1 y Birdseye. Se determinó el cambio neto y el cambio relativo porcentual para cada tipo de uso de suelo a lo largo del tiempo, así como la tasa anual de cambio mediante la ecuación propuesta por Puyravaud. Los resultados indican una pérdida de cobertura de los bosques de galería y un aumento del área agrícola. En un periodo de 27 años (1995-2022), la tasa anual de cambio registrada fue de -0.55 %; por el contrario, para la agricultura fue de 0.51 %. Con base en los valores obtenidos, se concluye que la superficie de los bosques de galería del municipio Linares tiende a disminuir, en función del tiempo para convertirse en tierras agrícolas. Es importante detener esta tendencia, ya que los bosques de galería desempeñan un papel importante en la protección de la biodiversidad, los recursos hídricos y edáficos, por lo que deben ser recuperados y conservados.

Abstract Gallery forests are plant communities that grow along rivers and streams. They provide numerous ecosystem services, but like other vegetation associations they are strongly threatened by anthropic activities such as agriculture. The objective of the present study was to know the current state of the gallery forests of Linares municipality, state of Nuevo León, by means of a multitemporal analysis of land use change and vegetation cover in four periods: 1995-2008, 2008-2014, 2014-2022 and 1995-2022. The analysis used high-resolution space images from the Airbus Defence and Space, GeoEye-1 and Birdseye satellites. The net change and relative percentage change for each type of land use was determined over time, as well as the annual rate of change using the equation proposed by Puyravaud. As a result, a loss of coverage of gallery forests and an increase in agricultural area was found. Over a period of 27 years (1995-2022), the annual rate of change for gallery forests was -0.55 %, whereas for agriculture it was 0.51 %. Considering the values obtained, it is concluded that the area of the gallery forests of Linares municipality tends to decrease according to the time to become agricultural land. It is important to stop this trend, as gallery forests play an important role in protecting biodiversity, water and soil resources and must be recovered and preserved.

The partial or complete loss of vegetation cover triggers an increase in surface runoff, erosion, and sedimentation of water bodies, including reservoirs for hydroelectric power generation, reducing their life expectancy. To control or mitigate this issue, ecological restoration interventions should prioritize the recovery of areas most vulnerable to these processes, such as springs. Conversely, wildfires cause damage to vegetation cover and hinder ecological restoration and/or natural regeneration processes. Therefore, this study aimed to identify - with the aid of Geographic Information Systems - the temporal and spatial likelihood of fire occurrences in spring recharge areas undergoing ecological restoration and contributing to hydroelectric reservoirs in southern Minas Gerais, Brazil. The findings indicated that the months with the highest probability of wildfire occurrences were August and September (accounting for 66% of cases), requiring increased attention to prevention efforts. Furthermore, locations most susceptible to fires (steeper slopes, more flammable vegetation, and higher anthropogenic use) should be treated as priorities for both prevention and ecological restoration actions

A perda parcial ou total da cobertura vegetal desencadeia um aumento do escoamento superficial, erosão e assoreamento de corpos hídricos, entre eles os reservatórios para a geração de energia hidroelétrica, reduzindo sua expectativa de vida útil. Para tentar controlar ou corrigir este problema, intervenções de restauração ecológica devem priorizar a recuperação de áreas mais frágeis a estes processos, como as nascentes. Por outro lado, a ocorrência de incêndios promove danos à cobertura vegetal e inibem os processos de restauração ecológica e/ou regeneração natural. Desta forma, o objetivo deste estudo foi identificar - com o auxílio de Sistemas de Informações Geográficas - a época mais provável e os locais mais susceptíveis aos incêndios, em áreas de recarga de nascentes sob processo de restauração ecológica e que são contribuintes de reservatórios hidroelétricos no sul de Minas Gerais, Brasil. Os resultados demonstraram que os meses de maior probabilidade de ocorrências de incêndios florestais foram agosto e setembro (66% dos casos), o que exigirá maior atenção quando das ações de prevenção. Bem assim, que os locais mais susceptíveis à ocorrência de incêndios (maior inclinação, vegetação mais inflamável e maior uso antrópico) necessitarão ser tratados como prioritários, tanto para ações de prevenção quanto de restauração ecológica

Abstract The estimation and variation of the vegetation cover of the Amazon forest generated by anthropic activity in Huepetuhe had the purpose of estimating the loss of vegetation and the deforestation rates for an Amazon forest, the study was carried out using Landsat 8 satellite images, the treatment of the raster images was made using the ERDAS software, the images were subjected to geometric and radiometric corrections, for this purpose control points were taken on the ground, for the analysis four categories of forest degradation were established: Forest with null vegetation with presence of bare soil, forest with sparse vegetation, forest with moderate vegetation and total area of deterioration. The results from the analysis of the multispectral images and the NDVI show that compared to 2016, 30.1 ha increased in the forest category with no vegetation, 28.8 ha in forests with sparse vegetation, 236.9 ha for forests with moderate vegetation and the area of global deterioration increased by 295.8 ha. The annual deforestation rate was 5% (6.02 ha/year) for forests with no vegetation and presence of bare soil and 9% (59.16 ha/year) for global degradation, the coefficient of determination for forests with no vegetation and area naked was R2=0.9704, and for global deterioration of the forest R2=0.957.

Resumen La estimación y variación de la cobertura vegetal del bosque amazónico generada por la actividad antrópica en Huepetuhe tuvo por finalidad estimar las pérdidas de vegetación y las tasas de deforestación para para un bosque amazónico, el estudio se realizó utilizando la herramienta Google Earth Engine e imágenes satelitales Landsat 8, para el tratamiento de las imágenes ráster se utilizó el software ERDAS y ArcGis, las imágenes fueron sometidas a correcciones geométricas y radiométricas, para ello se tomaron puntos de control el tierra, para el análisis se estableció cuatro categorías de degradación del bosque: Bosque con vegetación nula con presencia de suelo desnudo, Bosque con vegetación escasa, Bosque con vegetación moderada y área total de deterioro. Los resultados a partir del análisis de las imágenes multiespectrales y el NDVI muestra que respecto al año 2016 se incrementó 30.1ha en la categoría bosque con vegetación nula, 28.8 ha en los bosques con vegetación escasa, 236.9 ha para bosques de vegetación moderada y el área de deterioro global se incrementó en 295.8 ha. La tasa de deforestación anual fue del 5% (6.02 ha/año) para bosque con vegetación nula y presencia de suelo desnudo y del 9% (59.16 ha/año) para degradación global, el coeficiente de determinación para bosques con vegetación nula y área desnuda fue de R2=0.9704, y para deterioro global del bosque R2=0.957.

Abstract Urban trees play an important role within cities due to the environmental services they provide and their contribution to mitigating the current climate crisis. In this context, the objective of this study was to evaluate the tree vegetation of five public parks in the Texcoco de Mora municipality in order to estimate the environmental services they provide. A census was carried out per park and the data were processed through the i-Tree® Eco v6 software. 1 325 individuals from 23 families and 37 genera were recorded with a richness of 55 species in the five parks, an average density of 157 trees ha-1 and a total of 242.6 megagrams of carbon storage with a carbon capture of 10.5 Mg year-1. The avoided rain runoff was 481 m3 year-1 and the value represented by these environmental services is MXN $894 514.93 for carbon storage, MXN $38 650 annually for carbon capture, and MXN $481.93 for runoff. The replacement value of the trees reaches MXN $24 408 534. A tree cover of 30 485 m2 was estimated, which represents a factor of 0.86 m2 inhabitant-1. It is concluded that Texcoco is below the recommended factor of trees per inhabitant proposed by the UN. It is necessary to study the green areas, medians, alignment trees and community parks, to achieve a more complete panorama of the municipality.

Resumen El arbolado urbano desempeña un papel importante dentro de las ciudades por los servicios ambientales que provee y por su contribución a la mitigación de la actual crisis climática. En ese contexto, el objetivo del presente estudio consistió en evaluar la vegetación arbórea de cinco parques públicos del municipio Texcoco de Mora a fin de estimar los servicios ambientales que proporcionan. Se realizó un censo por parque y se procesaron los datos a través del software i-Tree ® Eco V6. Se registraron 1 325 individuos de 23 familias y 37 géneros con una riqueza de 55 especies en los cinco parques, una densidad promedio de 157 árboles ha-1 y un total de 242.6 megagramos de almacenamiento de carbono con una captura de 10.5 Mg año-1. El escurrimiento de lluvia evitado fue de 481 m3 año-1 y el valor que representan estos servicios ambientales en pesos es de MXN $894 514.93 para el almacenamiento de carbono, MXN $38 650 anuales para la captura del mismo y MXN $481.93 para el escurrimiento. El valor de sustitución del arbolado es de MXN $24 408 534.00. Se estimó una cobertura arbórea de 30 485 m2, lo cual representa un factor de 0.86 m2 habitante-1. Se concluye que Texcoco está por debajo del factor recomendado de arbolado por habitante propuesto por la ONU. Es necesario estudiar las áreas verdes, camellones, árboles de alineamiento y parques comunitarios para tener un panorama del municipio más completo.

Abstract Background: Roadside plants grow along transportation routes, and are little studied. Questions: What is the richness of roadside angiosperms? What is the percentage of native and introduced species for roadside angiosperms? Species studied: Native and introduced roadside angiosperms. Site and years of study: Chalma-Malinalco roadside, municipality of Malinalco, State of Mexico, Mexico, May 2008-April 2009. Methods: Angiosperm species were collected along the road right-of-way during 24 biweekly walks. Additionally, species were listed and their cover estimated in 14 sampling sites (4 m2 each). Results: We recorded 327 species. Asteraceae, Fabaceae and Poaceae were the families with the highest richness of genera and species. Native species were dominant (85.9 %), whereas introduced species grouped 14.1 %; the latter came mainly from the Old World. About 70 % of the species were herbs. Bouteloua repens and Eleusine indica had the highest cover and frequency, respectively. Conclusions: The roadside flora was rich in angiosperms, mostly herbs, and with a dominance of native plants. Introduced grasses played an outstanding role in terms of frequency. It is necessary to continue with floristic, ecological and ethnobotanical research, among others, on this group of plants that has been scarcely studied.

Resumen Antecedentes: Las plantas viarias crecen en las orillas de vías de comunicación y han sido poco estudiadas. Preguntas: ¿Cuál es la riqueza de las angiospermas viarias? ¿Cuál es el porcentaje de especies nativas e introducidas entre las angiospermas viarias? Especies de estudio: Angiospermas viarias nativas e introducidas. Sitio y años de estudio: Carretera Chalma-Malinalco, municipio de Malinalco, Estado de México, México, mayo 2008-abril 2009. Métodos: Se recolectaron las especies de angiospermas en el derecho de vía de la carretera a través de 24 recorridos quincenales. Adicionalmente, se enlistaron las especies y se estimó su cobertura en 14 cuadros de muestreo (4 m2 cada uno). Resultados: Se registraron 327 especies. Asteraceae, Fabaceae y Poaceae fueron las familias con mayor riqueza de géneros y especies. Las especies nativas fueron dominantes (85.9 %), mientras que las introducidas agruparon el 14.1 %; éstas últimas procedieron principalmente del Viejo Mundo. Alrededor del 70 % de las especies fueron hierbas. Bouteloua repens y Eleusine indica presentaron mayor cobertura y frecuencia, respectivamente. Conclusiones: La flora viaria era rica en angiospermas, la mayoría hierbas y con dominancia de plantas nativas. Los pastos introducidos tenían un papel sobresaliente en cuanto a frecuencia. Es necesario continuar con investigaciones florísticas, ecológicas, etnobotánicas, entre otras, sobre este grupo de plantas que ha sido escasamente estudiado.

Abstract The forests of the Yucatán Peninsula have been periodically subjected to various natural and anthropogenic disturbance factors, among these are the occurrence of hurricanes and logging, the latter with a history of more than 300 years. The use of remote sensing has been widely employed for forest cover management and other land uses. Satellite information allows the calculation of several indexes that are useful for purposes of forest management, one of the most widely used is the Normalized Difference Vegetation Index (NDVI), which is associated with the fraction of solar radiation absorbed by plants. The objective of this study was to analyze the spatial-temporal dynamics of the NDVI changes in a region under forest harvesting in the state of Quintana Roo and determine their possible causes during the 1985-2022 period. A time series of NDVI values was generated from Landsat sensor images for the years 1985, 1993, 2000, 2010 and 2022. Differences in NDVI values were wide and appear to follow the recurrence of hurricanes in the region. Logging did not explain the upward and downward patterns in NVDI values, nor did these patterns coincide with the changes in vegetation, as they do not change the land cover characteristics. These results provide partial evidence that significant changes in vegetation characteristics occur only after major and extensive disturbances such as hurricanes.

Resumen Las selvas de la Península de Yucatán han estado sujetas periódicamente a diferentes factores de perturbación natural y antropogénica, entre ellos la ocurrencia de huracanes y el aprovechamiento maderable, este último con una historia de más de 300 años. El uso de sensores remotos se ha empleado ampliamente para la gestión de coberturas forestales y otros usos del suelo. La información satelital permite el cálculo de diversos índices útiles para la administración forestal, uno de los más usados es el Índice de Vegetación de Diferencia Normalizada (NDVI) que se asocia a la fracción de la radiación solar absorbida por las plantas. El objetivo del presente estudio fue analizar la dinámica espacio-temporal de los cambios en el NDVI en una región con aprovechamiento maderable en el estado de Quintana Roo y determinar sus posibles causas durante el periodo 1985-2022. Se generó una serie de tiempo de valores de NDVI en imágenes de los sensores Landsat para los años 1985, 1993, 2000, 2010 y 2022. Las diferencias en los valores del NDVI fueron amplias y parecen seguir la recurrencia de huracanes en la región. La tala forestal no explicó los patrones al alza y a la baja en los valores del NVDI, ni coincidieron con las modificaciones en la vegetación, ya que no cambian las características de la cobertura del suelo. Estos resultados proporcionan evidencia parcial de que cambios significativos en las características de la vegetación solo ocurren después de perturbaciones importantes y extensas como los huracanes.

ABSTRACT: In this work we use Machine Learning (Randon Forest) as a tool to classify biomass and calculate vegetation indices seeking to identify the characteristics of the vegetation cover at the head of the Atacama Desert. The aim is to establish the correlation between vegetation indices and precipitation, in order to know their reliability on the climatology in this region. The geospatial analysis based on Google Earth Engine (GEE) and the processing of Landsat 5 ETM and Landsat 8 OLI/TIRS images was important, for the period 1985 - 2022, which made it possible to characterize climate change. The NDVI, SAVI, GVI and RVI have been tested and validated in arid systems. The NDVI responds positively to precipitation in the wet season and weakly in the winter rainy season. It is confirmed that the high NDVI corresponds to summer, after a prolonged drought. Towards the years 2020 and 2022, an increase in vegetation cover is recorded in places with higher temperatures, evidencing climate change and reflected in biomass indices.

RESUMEN: En este trabajo usamos Machine Learning (Randon Forest) como herramienta para clasificar la biomasa y calcular los índices de vegetación buscando identificar las características de la cobertura vegetal en la cabecera del desierto Atacama. Se busca establecer la correlación entre los índices de vegetación y la precipitación, a fin de conocer su confiabilidad sobre la climatología en esta región. Fue importante el análisis geoespacial basado en Google Earth Engine (GEE) y el procesamiento de imágenes Landsat 5 ETM y Landsat 8 OLI/TIRS, para el período 1985 - 2022, lo que permitió caracterizar el cambio climático. El NDVI, SAVI, GVI y RVI han sido probados y validados en sistemas áridos. El NDVI responde positivamente a la precipitación en temporada húmeda y en forma débil en la temporada de lluvias invernales. Se confirma que el NDVI alto corresponde al verano, después de una sequía prolongada. Hacia los años 2020 y 2022, se registra un aumento de cobertura vegetal en lugares de mayor temperatura, evidenciando cambio climático y reflejado en los índices de biomasa.

ABSTRACT This study aimed to model nutrient losses in an Oxisol under varied soil properties and vegetation cover. The experimental area was located at the Paraná Rural Development Institute, in Santa Tereza do Oeste, Paraná, Brazil. The treatments consisted of six cover crops in summer, six cover crops in winter, and management systems no-tillage (NT) traditional (control), NT with gypsum, and NT with scarification. Nutrient data were collected at each natural rainfall through sample collection from collection troughs. The design was completely randomized, and the data were adjusted using an exponential function of two variables, as a function of soil density, macroporosity, straw dry mass, green cover, and rainfall. Greater losses of Mg and Ca was related to higher soil density and lower macroporosity. Lower losses of Mg, Ca, K, and P were associated with lower straw dry mass and higher green cover. K and P losses were stable for all soil density values, but they decreased with an increase in macroporosity. Institute Oeste Brazil summer winter notillage no tillage (NT control, control , (control) gypsum scarification troughs randomized variables macroporosity values (control

ABSTRACT. Conservation practices such as no-tillage are necessary to maintain, and/or improve agricultural soil quality. However, straw formation and maintenance in tropical regions is a limiting factor to adopting this system. In this sense, this research aimed to study the effect of cover crops on straw formation, soil quality indicators, and cowpea yield under no-tillage in the Amazon savanna. Two experiments were carried out in consecutive years, on a Latossolo Amarelo. The treatments consisted of the straw of cover crops in a single (S) and intercrop (I) system, as follows: Urochloa brizantha (UBS), Pennisetum glaucum (PGS), Crotalaria juncea (CJS), Canavalia ensiformis (CES), Mucuna aterrima (MAS), U. brizantha and C. juncea (UBCJI), U. brizantha and C. ensiformis (UBCEI), P. glaucum and C. juncea (PGCJI), P. glaucum and C. ensiformis (PGCEI), and spontaneous vegetation (SV). Cowpea was cultivated after desiccation of the cover crops. Most of the straw favored soil particle aggregation, except for C. juncea and SV, which negatively influenced this variable. Basal soil respiration, organic carbon content, potassium, base saturation, geometric mean diameter, macroaggregates, and macroporosity at layer of 0-0.10 m were the most sensitive indicators for improving soil quality in a savanna environment. UBS, UBCJI, and UBCEI were superior to the other treatments in improving soil quality. Almost all treatments increased cowpea yield by up to 29%, except for CJS and SV. ABSTRACT notillage no tillage maintain andor or However system sense years Amarelo S (S I (I follows UBS , (UBS) PGS, PGS (PGS) CJS, (CJS) CES, CES (CES) MAS, MAS (MAS) U C UBCJI (UBCJI) UBCEI, (UBCEI) P PGCJI, PGCJI (PGCJI) PGCEI, PGCEI (PGCEI) SV . (SV) aggregation variable respiration content potassium saturation diameter macroaggregates 00.10 0010 0 0.10 10 0-0.1 environment 29 29% (UBS (PGS (CJS (CES (MAS (UBCJI (UBCEI (PGCJI (PGCEI (SV 00 00.1 001 010 0.1 1 0-0. 2 00. 01 0. 0-0 0-