Urbanization is a major driver of stream ecosystem impairment and is typically associated with multiple stressors and species loss. A challenge is to understand how those stressors alter the relationship between biodiversity and ecosystem functioning (B-EF). Amongst the Andean streams of southern Ecuador, we assessed the response of shredder diversity and organic matter breakdown (OMB) to urbanization and identified the urban-associated stressors disrupting the B-EF relationship. A leaf-litter bag experiment during stable flow conditions in 2016 was carried out to quantify total OMB and shredder-mediated OMB, which was estimated to represent the B-EF relationship. We calculated the taxonomic and functional diversity of shredder invertebrates associated with leaf packs. Also, a suite of physicochemical and habitat stressors was measured weekly during the field experiment. Along with the urbanization gradient, both taxonomic and functional diversity of shredders declined while OMB rates decreased. Shredders were absent and their contribution to OMB was null at the most urbanized sites. The B-EF relationship was interrupted through nutrient enrichment, physical habitat homogenization, riparian vegetation disturbance, and leaf-litter availability as a consequence of urbanization. Our results demonstrate how species loss spreads to and affects ecosystem functions in urbanized streams and how environmental stressors alter the B-EF relationship. Better land-use practices are crucial in Andean catchments to guarantee ecosystem services which are the result of successful B-EF relationships.

Organic and conventional agriculture are vital for the development of human society; however, the use of contaminated water and the inappropriate use of organic chemical fertilizers can lead to an increase in the microbial load (potentially pathogenic) of the normal microbiota of the agricultural soil. In this context, the aim of our study was to isolate Gram-negative bacteria from the superficial soil layer and irrigation water of agricultural areas (11 organic farms and nine conventional farms) and consider their potential ecological and health risk importance. Through culture isolation using three bacterial media (TSA) trypticase soy agar (general nutritive media); MacConkey Gram-negative bacteria and (EMB) eosin methylene blue agar (selective for Enterobacteriaceae) and classical biochemical tests, we recorded a total of 12 bacterial species, most belonging to the Enterobacteriaceae family, such as Enterobacter, Escherichia, Klebsiella, Salmonella and Shigella, which can be pathogenic for humans and animals. In contrast, bacteria such as Pantoea agglomerans, Pseudomonas aeruginosa, P. fluorescens and Burkholderia mallei could facultatively work as diazotrophic or plant growth-promoting rhizobacteria. Soil bacteria richness detected with the media applied was significantly higher than water bacteria, but we found no significant differences between organic and conventional agriculture. We conclude that the isolated bacteria in water and soil mostly belongs to enteropathogenic bacteria which could be pathogenic to animals and humans. While other bacteria like Pseudomonas aeruginosa could be viewed as useful by improving nutrient availability in agricultural soil.

Urbanization is a major driver of stream ecosystems impairment and often associated with multiple stressors and species loss. A challenge is to understand how those stressors alter the relationship between biodiversity and ecosystem functioning (B-EF). In Andean streams of southern Ecuador, we assessed the response of shredder diversity and organic matter breakdown (OMB) to urbanization and identified the urban-associated stressors disrupting the B-EF relationship. A leaf-litter bag experiment during stable flow conditions in 2016 was carried out to quantify total OMB and shredder-mediated OMB, which was estimated to represent the B-EF relationship. We calculated the taxonomic and functional diversity of shredder invertebrates associated with leaf packs. Also, a suite of physicochemical and habitat stressors was weekly measured during the field experiment. Along the urbanization gradient, both taxonomic and functional diversity of shredders declined while OMB rates decayed. Shredders were absent and their contribution to OMB was null at the most urbanized sites. The B-EF relationship was interrupted through nutrient enrichment and physical habitat homogenization as a consequence of urbanization. These results demonstrate how species loss propagates to ecosystem functions in urbanized streams and how environmental stressors alter the B-EF relationship. Better land-use practices are crucial in Andean catchments to guarantee ecosystem services which are the result of a successful B-EF relationships.

El fenómeno El Niño-Oscilación del Sur (ENOS) involucra una compleja interacción entre la atmósfera y el océano Pacífico tropical, caracterizada por anomalías en la temperatura superficial del mar (TSM) y en los patrones de circulación atmosférica (Wang et al, 2017). ENOS consiste en dos fases: El Niño, asociada al calentamiento anómalo del Pacífico central y oriental, y La Niña, caracterizada por un enfriamientoanómalo de estas regiones (Liguori et al, 2022). Este fenómeno natural presenta variaciones irregulares en su intensidad y periodicidad, las cuales tienen una amplia influencia en el clima y los ecosistemas de diversas regiones del mundo (Bendix et al, 2008).

We document the first record of Vanellus resplendens (Tschudi, 1843) (Charadriidae) in Podocarpus National Park, southern Ecuador. On 15 May 2025, an adult was observed at 2,802 m a.s.l. in El Tiro (Abra de Zamora), Zamora Chinchipe. This record extends the species’ Ecuadorian range 60 km east from El Oro and 110 km south from Azuay, reduces the gap between northern and southern portions of its discontinuous Andean distribu-tion, and underscores the park’s importance for conserving high‑Andean bird assemblages.

Aquatic macroinvertebrates inhabit virtually all freshwater ecosystems, yet communities in extreme saline environments remain largely undescribed, particularly in the Tropical Andes. This study characterizes the taxonomic diversity of aquatic macroinvertebrates in a travertine-fed saline stream (salinity: 12.5 ± 0.2 g/L; 2520 m a.s.l., southern Ecuador) and compares it with an adjacent freshwater stream. Macroinvertebrates were sampled on four occasions (n = 4 events per stream) using a multi-habitat D-net technique; physicochemical variables were compared with Mann–Whitney U exact tests, and diversity metrics with exact permutation tests (C(8,4) = 70 permutations) supplemented with Cliff’s delta as effect-size estimator. Community composition was assessed with ANOSIM and non-metric multidimensional scaling (NMDS). A total of 919 individuals were collected. The freshwater stream harbored significantly greater richness (49 genera, 28 families), abundance, and Shannon diversity than the saline stream (14 genera, 8 families; all p = 0.029, Cliff’s δ = 1.00), while Pielou’s evenness did not differ between stream types. Community composition was fully separated (ANOSIM R = 1.00, p = 0.028), with salinity (R² = 0.95, p < 0.01) and water temperature (R² = 0.79, p = 0.03) as the primary environmental drivers. The saline stream was dominated by halotolerant Diptera (Ceratopogonidae, Stratiomyidae) and water mites (Hydrachnidae), with virtually no EPT (Ephemeroptera–Plecoptera–Trichoptera) representation. These findings establish the first macroinvertebrate diversity baseline for a travertine-associated saline stream in the Tropical Andes, highlighting salinity and temperature as key environmental filters of aquatic biodiversity in extreme Andean lotic ecosystems.