The antifouling booster biocides are frequently studied for toxic effects on the aquatic ecosystems. The present investigation proposes passive silicone rubber samplers as a collection method for biocides, once these methods can concentrate substances in aqueous matrices at very low levels. Through the passive sampler-water partition coefficient (Ksw) and the analyte chemical nature, we can optimize their extraction from the membrane to apply in the sample medium. We used the co-solvent method to determine the Ksw of three third-generation antifouling biocides, chlorothalonil, dichlofluanid, and dichlorooctylisothiazolinone (DCOIT), with log Ksw = 2.24, 4.01, and 2.38, respectively. Improving extraction also led to a recovery range higher than 70%, determinations were carried out by gas chromatography with an electron capture detector. Biocides concentration in seawater samples from Itaqui port (São Marcos Bay, northern Brazil) ranged from 0.058 to 0.72 µg L-1 for chlorothalonil, 0.001 to 0.008 µg L-1 for dichlofluanid, and 0.018 to 0.64 µg L-1 for DCOIT. ecosystems levels samplerwater sampler water (Ksw nature medium cosolvent co solvent thirdgeneration third generation chlorothalonil dichlofluanid DCOIT, DCOIT , (DCOIT) 224 2 24 2.24 401 4 01 4.01 238 38 2.38 respectively 70 70% detector São Bay Brazil 0058 0 058 0.05 072 72 0.7 L1 L 1 L- 0001 001 0.00 0008 008 0018 018 0.01 064 64 0.6 (DCOIT 22 2.2 40 4.0 23 3 2.3 7 005 05 0.0 07 0. 000 00 06 6 2. 4.

The selective separation of precious metals from complex aqueous solutions is important in protecting the environment, aquatic ecosystems, water resources and recycling resources. In this study, cysteine-containing polymeric nanoparticles were synthesized using the molecular imprinting (MIP) technique with the mini-emulsion polymerization method. The basis of the polymer design is inspired by affinity of silver to cysteine in biological systems. The synthesized silver ion imprinted (Ag+-IIP) poly(hydroxyethylmethacrylate-N -methacryloyl-L-cysteine) poly(HEMA-MAC) nanoparticles were characterized by elemental analysis, zeta sizer, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). The effects of pH, ionic strength and interaction time on adsorption of Ag+ ions were investigated. In experimental studies, the highest adsorption amount (196.9 mg g1 nanoparticle) was reached in a short period of 40 min at pH 5.0 and 150 mg L-1 concentration. Selectivity studies of synthesized Ag+-IIP nanoparticles against silver (Ag+) ions were carried out in the presence of lithium (Li+), barium (Ba2+), mercury (Hg2+) and cadmium (Cd2+) ions. Experimental results indicate that nanoparticles adsorb Ag+ ions with high selectivity. Ag+-IIP nanoparticles have 3.7, 3.1, 2.4, and 2.6 times more selective or higher affinity for Ag+ ions compared to Li+, Ba2+, Hg2+ and Cd2+ ions, respectively, compared to Ag+-non-imprinted (NIP) nanoparticles. environment ecosystems study cysteinecontaining containing MIP (MIP miniemulsion mini emulsion method systems Ag+IIP AgIIP IIP Ag (Ag+-IIP polyhydroxyethylmethacrylateN poly hydroxyethylmethacrylate N methacryloylLcysteine methacryloyl L -methacryloyl-L-cysteine polyHEMAMAC HEMA MAC poly(HEMA-MAC analysis sizer FTIR (FTIR spectroscopy AFM, AFM , (AFM) SEM. SEM . (SEM) investigated 196.9 1969 196 9 (196. g nanoparticle 4 50 5 0 5. 15 L1 1 L- concentration (Ag+ Li Li+ (Li+) Ba2 Ba Ba2+ (Ba2+) Hg2 Hg (Hg2+ Cd2 Cd (Cd2+ selectivity 37 3 7 3.7 31 3.1 24 2 2.4 26 6 2. respectively Ag+nonimprinted Agnonimprinted non NIP (NIP (AFM (SEM 196. 19 (196 (Ag (Li+ (Ba2+ (Hg2 (Cd2 3. nonimprinted (19 (Li (Ba2 (Hg (Cd (1 (Ba (

Phosphate species can affect aquatic ecosystems, as excess of this nutrient can cause eutrophication, generating environmental impacts. Lamellar double hydroxides have shown promise in removing phosphate at low concentrations (10-50 mg L 1). In this context, lamellar double hydroxides were synthesized interspersed with nitrates and humic substances, searching for a new product that favors phosphorus adsorption. X-ray diffraction showed the presence of characteristic peaks of lamellar double hydroxides and thermogravimetric analysis showed the decomposition behavior of lamellar structure. The adsorption capacity occurred quickly (< 30 min), being more efficient for lamellar double hydroxides with NO3. The maximum adsorption capacity showed results of 35.03 and 44.20 mg g 1 for lamellar double hydroxides with humic substances and lamellar double hydroxides with NO3, respectively. The complexation capacity showed that pH directly influences complexation, being greater for lamellar double hydroxides with humic substances at pH 6.5. Thus, nanostructured materials with humic substances are promising for use in contaminant remediation and adsorption can be a fast and efficient technique for use in soil and water. ecosystems eutrophication impacts 1050 10 50 (10-5 1. . 1) context Xray X ray structure < ( 3 min, min , min) NO3 NO 3503 35 03 35.0 4420 44 20 44.2 respectively 65 6 5 6.5 Thus water 105 (10- 350 0 35. 442 4 2 44. 6. (10 (1

Abstract Introduction: Various anthropic pressures affect the aquatic ecosystems of the foothills of Colombia. The response to environmental stressors is still unknown in bioindicator organisms such as Leptohyphidae. Objective: To determine the diversity of Leptohyphidae nymphs of the Quenane-Quenanito river, in two contrasting hydrological periods and its relationship with some physicochemical variables. Methods: In December (2014) and February (2015), organisms were collected with a Surber net at six stations along the current. Alpha and beta diversity was analyzed and redundancy analysis and generalized linear model were applied to establish the relationship between taxa and environmental variables. Results: Were identified 369 organisms belonging to four genera (Amanahyphes, Traverhyphes, Tricorythopsis, and Tricorythodes), two species, and eight morphospecies. Amanahyphes saguassu is reported for the first time for the Meta department. High diversity of Leptohyphidae nymphs was recorded in the transition to drought season and greater abundance in drought. Beta diversity indicated that the configuration of the assemblage changes spatially and temporally. Conclusions: Leptohyphidae organisms prefer fast habitats, particularly in the dry period where they find food (leaf litter, detritus) and shelter to establish themselves successfully; anthropic activities such as urbanization notably affect diversity. The high diversity recorded in this small river in the foothills of the plains reflects the need to increase this type of works and collection efforts of study material in the region.

Resumen Introducción: Varias presiones antrópicas sufren los ecosistemas acuáticos del piedemonte llanero en Colombia. La respuesta a estresores ambientales aún se desconoce en organismos bioindicadores como Leptohyphidae. Objetivo: Determinar la diversidad de ninfas de Leptohyphidae del río Quenane-Quenanito, en dos periodos hidrológicos contrastantes y su relación con algunas variables fisicoquímicas. Métodos: En diciembre (2014) y febrero (2015) se recolectaron organismos con red Surber en seis estaciones a lo largo del río. Se analizó la diversidad alfa y beta y se aplicó análisis de redundancia y modelos lineales generalizados con el fin de establecer la relación entre los taxones y las variables ambientales. Resultados: Se identificaron 369 organismos pertenecientes a cuatro géneros (Amanahyphes, Traverhyphes, Tricorythopsis y Tricorythodes), dos especies y ocho morfoespecies. Se reporta por primera vez para el departamento del Meta Amanahyphes saguassu. Se registró la mayor diversidad de ninfas en la transición a la sequía y la mayor abundancia en sequía. La diversidad beta señaló que la configuración del ensamblaje cambia a nivel espacial y temporal. Conclusiones: Los organismos de Leptohyphidae prefieren hábitats de corrientes, particularmente en el periodo de sequía, donde hallan alimento (hojarasca, detritos) y refugio para establecerse exitosamente; actividades antrópicas como la urbanización afectan notablemente la diversidad. La alta diversidad registrada en este pequeño río de piedemonte llanero refleja la necesidad de incrementar este tipo de trabajos y esfuerzos de recolección de material de estudio en la región.

Resumen: La cuenca binacional del río Zarumilla es un lugar con gran diversidad de especies y es de gran importancia para la economía de Perú y Ecuador. Estos factores socioeconómicos pueden traer consigo cambios en la distribución de las coberturas del suelo, los cuales afectan de manera negativa los ecosistemas. El presente estudio tiene como objetivo evaluar los cambios de cobertura y uso de suelo durante el periodo 1992-2022 y construir una proyección al año 2040 siguiendo las tendencias de uso actuales y su patrón histórico. Se usaron mapas de cobertura y uso de suelo de los años 1992 y 2022, así como información georreferenciada que fue usada para encontrar los factores condicionantes para el cambio de suelo. El modelo de prospección se basó en la implementación de cadenas de Markov y autómatas celulares usando factores condicionantes para construir una proyección más precisa. Los resultados obtenidos reflejan una pérdida neta de 11378 hectáreas de bosque durante el periodo 1992-2022, ocurriendo el 87.7% de esta pérdida en el lado ecuatoriano de la cuenca. A este ritmo se puede prospectar una pérdida de bosque de 10552 hectáreas para el periodo 2022-2040, de igual manera prevista principalmente en el lado ecuatoriano. El modelo prospectivo también resalta que los principales cambios se producirán en áreas de baja altitud y en proximidad a fuentes hídricas y carreteras. Esta es una pérdida alarmante de bosque nativo, la cual se puede evitar mediante la creación de políticas de desarrollo sostenible y programas de ordenamiento territorial.

Abstract: The binational basin of the Zarumilla River is a place with great species diversity and is particularly important to the economy of Peru and Ecuador. These socioeconomic factors can lead to changes in land cover distribution, which negatively affect ecosystems. The present study aims to evaluate changes in land cover and use during the period 1992-2022 and to generate a projection for the year 2040 following current usage trends and historical patterns. Land cover and use maps from 1992 and 2022 were used, along with georeferenced information that was employed to identify the conditioning factors for land change. The prospection model was based on the implementation of Markov chains and cellular automata using conditioning factors to build a more accurate projection. The results obtained reflect a net loss of 11378 hectares of forest during the period 1992-2022, with 87.7% of this loss occurring on the Ecuadorian side of the watershed. At this rate, a forest loss of 10552 hectares can be projected for the period 2022-2040, similarly projected mainly on the Ecuadorian side. The projection model also highlights that the main changes will occur in low-altitude areas and in proximity to water sources and roads. This is an alarming loss of native forest, which can be avoided through the creation of sustainable development policies and land-use planning programs.

Resumen: Las Reservas Ecológicas, son la base primordial para la subsistencia de la biodiversidad, desempeñan funciones cruciales para el mantenimiento de los ecosistemas, especialmente, en la preservación de los servicios ecosistémicos de regulación del clima y suministro de agua. Determinar la capacidad de acumulación del COS en tres ecosistemas de la Reserva Ecológica Arenillas (REAR) y la influencia que tienen con los factores de profundidad y el tipo de suelo, fue el objetivo de la investigación. Se partió de la hipótesis que dichos factores ejercen un efecto sobre las propiedades físicas-químicas del suelo, provocando la variabilidad del carbono. Se establecieron 14 unidades de muestreo para los tres ecosistemas; 1) Intervenido, 2) Bosque deciduo y 3) Bosque arbustal deciduo, se extrajo de cada unidad dos muestras de suelo a profundidades de (0-10 y 10-30 cm), dando un total de 28 muestras. Los resultados revelaron diferencias significativas entre los tres tipos de ecosistemas, permitiendo afirmar que, en la REAR, el contenido de COS es mayor en el ecosistema de Bosque deciduo, que en los denominados Bosque arbustal deciduo y la zona Intervenida. Así mismo, los suelos del tipo Alfisol y Entisol en el Bosque deciduo presentaron la mayor capacidad de almacenamiento de COS, siendo la capa superficial la de mayor acumulación en los tres ecosistemas. Se concluyó que las bajas precipitaciones, el aumento de la temperatura y la esporádica vegetación producida por actividades antrópicas, afectan el almacenamiento de COS, limitando la prestación de servicios ecosistémicos relacionados con la captura de carbono edáfico.

Abstract: Ecological Reserves are the primary basis for the subsistence of biodiversity, they play crucial roles in the maintenance of ecosystems, especially in the preservation of ecosystem services of climate regulation and water supply. The objective of the research was to determine the accumulation capacity of COS in three ecosystems of the Arenillas Ecological Reserve (REAR) and the influence of depth factors and soil type. It was hypothesized that these factors exert an effect on the physical-chemical properties of the soil, causing carbon variability. Fourteen sampling units were established for the three ecosystems; 1) Intervened, 2) Deciduous Forest and 3) Deciduous shrub forest, two soil samples were extracted from each unit at depths of (0-10 and 10-30 cm), giving a total of 28 samples. The results revealed significant differences between the three types of ecosystems, allowing us to affirm that, in the REAR, the COS content is higher in the deciduous forest ecosystem than in the deciduous shrub forest and the Intermediate zone. Likewise, Alfisol and Entisol soils in the deciduous forest had the highest COS storage capacity, being the surface layer the one with the highest accumulation in the three ecosystems. It was concluded that low precipitation, increased temperature and sporadic vegetation produced by anthropic activities affect COS storage, limiting the provision of ecosystem services related to soil carbon sequestration.

ABSTRACT The territories ofNuestra Américahave been subjected to natural and sociopolitical dynamics that put them at risk. However, governmental authorities have preferred to implement strategies borrowed from the so-called developed countries rather than to develop their own strategies based on local past-experiences and knowledge. Therefore, from the need to reflect on the importance of construct proposals for the integral resilience of the territories, considering the characteristics and potential of local ecosystems and sociocultural aspects, the historical particularities and political ecology aspects stand out. Those are important in the construction or strengthening of resilience in Nuestra América.

RESUMEN Los territorios de Nuestra América han estado sometidos a dinámicas naturales y sociopolíticas que los ponen en riesgo. Sin embargo, las autoridades gubernamentales han preferido implementar estrategias de países considerados desarrollados, en lugar de aprender de las experiencias pasadas y emplear el conocimiento local. Por tanto, a partir de la necesidad de reflexionar sobre la importancia de construir propuestas para la resiliencia integral de los territorios, teniendo en cuenta las características y potencialidades ecosistémicas y socioculturales locales, se destacan las particularidades históricas y los aspectos de ecología política a considerar al pensar en la construcción o fortalecimiento de resiliencia en Nuestra América.

Resumen Representa una necesidad actual comprender y analizar el emprendimiento, como medio para identificar tendencias y guiar futuras investigaciones. El objetivo del presente estudio fue analizar la producción científica acerca del emprendimiento en la base de datos Scopus durante el periodo 2011-2021. Se recolectaron 4,245 artículos de la base de datos Scopus a través de una búsqueda sistemática de palabras claves y filtros con el método prisma. El análisis bibliométrico se realizó empleando los softwares de acceso libre VosViewer y Bibliometrix R. Como resultado se caracterizaron tendencias, se identificaron autores predominantes, países con implicancia en el desarrollo del emprendimiento, así como la evidencia del cumplimiento de la ley de Lotka en la producción científica. El análisis evidenció una tendencia hacia los ecosistemas empresariales; además se halló que el emprendimiento se encuentra vinculado a la innovación y los países que destacan a nivel global son Estados Unidos y China; mientras que en el mundo hispano fueron España y México. Finalmente se encontró evidencia que el emprendimiento promueve el desarrollo económico de las sociedades, particularmente de aquellas que requieren un impulso económico sostenido.

Abstract There is a current need to understand entrepreneurship as a means of identifying trends and guiding future research. The objective of this study was to analyze the scientific production on entrepreneurship in the Scopus database during the period 2011-2021. A total of 4,245 articles were collected from the Scopus database through a systematic keyword search and filters using the prism method. The bibliometric analysis was carried out using the open access software VosViewer and Bibliometrix R. As a result, trends were characterized, predominant authors were identified, countries with implications for the development of entrepreneurship, as well as evidence of compliance with Lotka's law in scientific production. The analysis showed a trend towards entrepreneurial ecosystems; It was also found that entrepreneurship is linked to innovation and the countries that stand out globally are the United States and China; while in the Hispanic world it was Spain and Mexico. Finally, evidence was found that entrepreneurship promotes the economic development of societies, particularly those that require a sustained economic boost.

ABSTRACT Nowadays marine and coastal ecosystems are threatened by the invasion of harmful algal species. The solution to this situation should be aimed at the integral use of this biomass. The drying process has a decisive impact on the quality of the resulting raw material and the cost of any derived by-products. For this reason, the objective of this research is to evaluate the drying process of macroalgae: Sargassum fluitans, Ulva lactuca and Chaetomorpha cf. gracilis, using a solar dryer designed for this purpose. The drying process was evaluated at a temperature of 60°C. The results obtained reported that dehydration in the oven lasted less than 2 hours, while in the solar dryer values higher than those achieved in the oven were recorded. The first derivative analysis shows that the highest peak of moisture loss is around 80 % and is reached in the first 15 min in the electric stove. However, in solar drying it was recorded around 45 min. The results obtained in the drying process were adjusted to a polynomial model with a determination coefficient of 99,13 %

RESUMEN Hoy día los ecosistemas marinos y costeros se encuentran amenazados por la invasión de algas nocivas. La solución a esta situación necesariamente debe estar encaminada al aprovechamiento integral de esta biomasa. El proceso de secado tiene un impacto decisivo en la calidad de la materia prima resultante y el costo de cualquier subproducto derivado. Por este motivo el objetivo de esta investigación es evaluar el proceso de secado de las macroalgas: Sargassum fluitans, Ulva lactuca y Chaetomorpha cf. gracilis, utilizando un secador solar diseñado al efecto. El proceso de secado fue evaluado a una temperatura de 60°C. Los resultados obtenidos reportaron que la deshidratación en la estufa tuvo una duración inferior a las 2 h, mientras que en el secador solar se registraron valores superiores a los alcanzados en la estufa. El análisis de la primera derivada muestra que el mayor pico de pérdida de humedad está alrededor del 80 % y se alcanza en los primeros 15 min en la estufa eléctrica. Sin embargo, en el secado solar se registró alrededor de los 45 min. Los resultados obtenidos en el proceso de secado fueron ajustados a un modelo polinomial con un coeficiente de determinación del 99,13 %.

ABSTRACT Toxic cyanobacteria blooms are an increasingly common global problem due to eutrophication, the effects of climate change and increased surveillance efforts in aquatic ecosystems. In Cuba, several ecosystems have been analyzed in the eastern region, demonstrating that this risk occurs to surface and inland waters, due to climatic conditions, mainly in small ecosystems with great human pressures. However, other areas are still unexplored. The objective of this work was to implement a risk management protocol in the San Blas Lagoon, Camaguey, due to the presence of toxic cyanobacteria in the ecosystem, following a community report, with the death of domestic and wild animals; unpleasant odors and dermatological symptoms in humans. A management protocol and community actions were implemented to minimize the impact of toxic cyanobacteria. In this small eutrophic reservoir, the presence of a mixed bloom of toxigenic cyanobacteria was confirmed, being Spherospermopsis torques-reginae the majority, as well as other nine species associated with the production of microcystins, anatoxins and/or cylindrospermopsins were identified. Strategic actions were implemented to contain the risk situation, with the participation of the community and experts, led by the Camagüey Criminalistics Laboratory.

RESUMEN Las floraciones de cianobacterias tóxicas constituyen un problema global cada vez más frecuente, debido a la eutrofización, los efectos del cambio climático y a un mayor esfuerzo de vigilancia en los ecosistemas acuáticos. En Cuba se han muestreado varios ecosistemas en la región oriental, demostrando que este riesgo existe en aguas superficiales e interiores, debido a las condiciones climáticas, principalmente en pequeños ecosistemas con grandes presiones humanas. Sin embargo, otras zonas están aún inexploradas. El objetivo de este trabajo fue implementar un protocolo de gestión de riesgos en la Laguna San Blas, debido a la presencia de cianobacterias tóxicas en el ecosistema, a raíz de un reporte comunitario, con muerte de animales domésticos y silvestres; olor desagradable y síntomas dermatológicos en humanos. Se implementó un protocolo de gestión y acciones comunitarias para minimizar el impacto de las cianobacterias tóxicas. En este pequeño reservorio eutrófico se confirmó la presencia de una floración mixta de cianobacterias toxigénicas, siendo mayoritaria Spherospermopsis torques-reginae, identificándose otras nueve especies asociadas a la producción de microcistinas, anatoxinas y/o cilindrospermopsinas. Se implementaron acciones estratégicas para contener la situación de riesgo, con la participación de la comunidad y expertos, liderados por el Laboratorio de Criminalística de Camagüey.

SIGNIFICANCE: The Freshwater Biodiversity Information System (FBIS) is a powerful, open-access platform for hosting, sharing, and analysing freshwater biodiversity data for South Africa. Platform design and functionality were strongly informed by the requirements of key data end-users and decision-makers. The platform has over 790 000 occurrence records, which are freely available to data-users and are now being converted into impact through incorporation in national decision-support tools. With better data comes better decisions, and access to a data repository like FBIS means that the monitoring, management and conservation of our freshwater ecosystems can be improved, for the long-term betterment of both people and biodiversity.

Verlorenvlei is a globally important RAMSAR wetland on the arid west coast of South Africa. A prolonged drought between 2016 and 2021 and increasing competition for water from the agricultural sector resulted in extremely low water levels. We used historical aerial and satellite imagery from 1942 and rainfall and water level data for the past 50 years, to assess habitat changes within the estuarine functional zone of the Verlorenvlei Estuarine Lake. Prior to the drought, lake water levels and water surface area remained stable (1113 ± 27 ha (SE)). Since then, there has been a 64% decrease in open water area, exposing 193 ha of sandbanks, of which 190.9 ha were hyper-sulfidic pyrite-rich. The water in the lower lake was hypersaline (>100), and in the middle, it was acidic (pH<3). The low water level plus sediment and nutrient input from surrounding agriculture resulted in a localised increase in reeds. Additional pressures, such as fires, have reduced the above-ground biomass of reeds and sedges, potentially altering surface morphology and reducing stored carbon. Despite flooding and filling up in June 2023, the lake remained in an acidic state (3.9-4.3). Similar low-lake level, hypersaline and acidic conditions are predicted to become more common under future climate change scenarios where aridity and extreme weather events are anticipated. Inflow of fresh water into the estuary and control of farming practices are required to keep the Verlorenvlei in a functional state, with long-term monitoring necessary to assess the ecological condition in response to restoration actions. SIGNIFICANCE: We assessed the habitat changes in Verlorenvlei, an estuarine lake on the arid west coast of South Africa. Estuarine lakes are scarce, and an extended drought greatly reduced the water surface area, exposing hyper-sulfidic pyrite-rich soils, leading to lake acidification and a negative response from biota. Competition for water from agribusiness and the burning of reeds are added pressures. Subsequent heavy rains have been slow to buffer lake acidity, and the impacts thereof serve as a warning for the management of similar ecosystems and their ecological water requirements, especially under climate change where extreme weather conditions, increased aridity and competition for water are realities.

Human societies depend on services provided by ecosystems, from local needs as clean water and pest control to global services like ozone layer and the ocean biological pump. Ecosystem services are intrinsically linked to the states of the ecosystem, which are, in turn, governed by a complex web of ecological interactions. These interactions and, consequently, the services they support, are increasingly under threat from environmental changes driven by human activities. Therefore, safeguarding these vital services require an understanding of how the structure and dynamics of ecological interactions are affected by environmental change. A critical step towards this goal is the development of an integrative theoretical framework that can elucidate how ecosystem services are sustained or impaired by interactions within these complex ecosystems in fluctuating environments. Recent years have seen significant progress in quantitatively characterizing the organization and the dynamics of ecological interactions through the study of ecological networks. However, linking temporally varying network structure in fluctuating environments, the seascapes of ecological networks, and their impact on ecosystem services remains a challenge. We propose an approach based upon merging empirical ecological network analysis with Boolean functions and modeling techniques accounting for fluctuating environments to tackle how ecosystem services are affected by the changing structure and dynamics of ecological networks. The approach aims to contribute to the study of how the organization of ecological interactions affects the persistence of ecosystem services. Specifically, we discuss how this approach can be used provide new insights into how environmental change affect the relationship between ecological networks and ecosystem services. The combination of information on ecosystem services, Boolean networks and fluctuating environments might allow to enhance the research around conservation strategies for preserving biodiversity and ecosystem services in the face of ongoing environmental change.

Abstract Background: Although drought and defoliation increase the risk of death of the seedlings in tropical dry forests, few studies have evaluated the impact of this combined factors on the response of species. Questions: What is the seedling water management strategy and how does it affect their growth? How does the combination of drought and defoliation impact the growth of the species? Studied species: Guazuma ulmifoliaLam andPithecellobium dulce(Roxb.) Benth. Study sites and dates: The study was carried out in Autlán, Jalisco, México, between October 2021 and February 2022. Methods: In a greenhouse, the seedlings were submitted to four combined water availability and defoliation treatments. The stomatal conductance and leaf water potential were recorded, and the relative growth rate, final biomass, and biomass allocation were calculated. Results: G. ulmifoliashowed to be an anisohydric species, registered higher growth, and was the most affected by drought, whileP. dulcewas more isohydric, registered lower growth and defoliation was the main stressor. The synergy between Drought × Defoliation negatively impacted the two species' relative growth rate. Conclusions: Regardless of the water management strategy, in the early phases of development, the impact of drought and defoliation was magnified when stressors interacted. Therefore, Drought × Defoliation can limit the regeneration of species within forests, promoting the loss of biodiversity and detriment to the functioning of ecosystems.

Resumen Antecedentes: Aunque la sequía y la defoliación incrementan el riesgo de muerte de las plántulas en los bosques tropicales secos, pocos estudios han evaluado la respuesta de las especies forestales con la combinación de estos factores. Preguntas: ¿Cuál es la estrategia de uso del agua de las plántulas y cómo afecta su crecimiento? ¿Cuál es el impacto de la combinación de Sequía × Defoliación sobre el crecimiento de las especies? Especies estudiadas: Guazuma ulmifolia Lam y Pithecellobium dulce (Roxb.) Benth. Sitio y año de estudio: Autlán, Jalisco, México, entre octubre del 2021 y febrero del 2022. Métodos: En invernadero, las plántulas se sometieron a cuatro tratamientos combinados de disponibilidad de agua y defoliación. Se registró la conductancia estomática y el potencial hídrico de la hoja, y se calculó la tasa de crecimiento relativa, biomasa final y asignación de biomasa. Resultados: G. ulmifolia mostró ser anisohídrica, registró mayor crecimiento y fue más afectada por la sequía, mientras que P. dulce fue más isohídrica, registró menor crecimiento y la defoliación fue el principal estresor. El impacto de la Sequía × Defoliación fue de sinergia en la tasa de crecimiento relativa en ambas especies. Conclusión: Independientemente de la estrategia de uso de agua, en las primeras fases de desarrollo, el impacto de la sequía y defoliación se magnificó cuando interactuaron los estresores. La Sequía × Defoliación pueden limitar la regeneración de las especies dentro de los bosques, promoviendo la pérdida de la biodiversidad y el detrimento del funcionamiento de los ecosistemas.

Abstract The objective of this work was to analyze the relationship between perceptions and agricultural practices in the face of the effects of climate change from the agro-socio-economic context and the hydrological structure in the Cochapata high-altitude ecosystem in Urcuquí-Ecuador. The methodological strategy responds to the qualitative paradigm, case study method. Primary information was collected through landscape reading, interviews, and participant observation. It was found that the territory is occupied by timber industries, whose tree species are characterized by excessive water demand. The sub-paramo is inhabited by peasants in survival conditions who use the land to obtain goods for family sustenance using their labor force. Water distribution is of a hydro-social nature, as it excludes peasants from the right to irrigation and watering. Regarding the effects of the changing climate, the inhabitants perceive heat waves and variations in the rainy season in their daily lives; however, no agricultural practices were found to adapt to the climatic phenomenon. It is concluded that the vulnerability of the ecosystem is not directly related to climate change; it responds to historical failures in the distribution of ecosystem goods such as land and water, to the lack of knowledge of the peasant subject on the part of the state and society, and the excessive extractivism implemented during the last decades.

Resumen El objetivo de este trabajo fue analizar la relación entre percepciones y prácticas agrícolas frente a los efectos del cambio climático desde el contexto agro-socio-económico y la estructura hidrológica en el ecosistema de altura Cochapata en Urcuquí-Ecuador. La estrategia metodológica responde al paradigma cualitativo, método de estudio de caso. Se levantó información primaria mediante lectura del paisaje, entrevistas y observación participante. Se encontró que el territorio está ocupado por industrias madereras cuyas especies arbóreas se caracterizan por excesiva demanda hídrica. El subpáramo está habitado por campesinos en condición de sobrevivencia que usan la tierra para obtener bienes de sustento familiar, valiéndose de su fuerza de trabajo. Se evidenció que la distribución del agua es de carácter hidrosocial, pues excluye al campesinado del derecho a riego y abrevadero. Respecto a los efectos del clima cambiante, los pobladores perciben en su cotidianidad olas de calor y variaciones en las temporadas de lluvias, sin embargo, no se encontraron prácticas agrícolas con intención adaptativa al fenómeno climático. Se concluye que la vulnerabilidad del ecosistema no guarda relación directa con el cambio climático, esta responde a las fallas históricas en la distribución de los bienes ecosistémicos tierra y agua, al desconocimiento del sujeto campesino por parte del Estado y de la sociedad, y al excesivo extractivismo implantado durante las últimas décadas.