The lack of knowledge about freshwater biodiversity in remote areas like montane Andean rivers is noticeable and hinder the development of efficient conservation plans for aquatic ecosystems. Habitat requirements of tropical Andean fishes have been poorly analysed, despite the relevance of these ecological features on the fish conservation strategies. The present study aimed to examine fish assemblages along the altitudinal gradient in tropical Andean rivers and their relationship to habitat features to detect the most relevant abiotic factors and their implication on conservation. This study was conducted on a regional scale, along six basins located in tropical Andes (500 to 2,692 m a.s.l.). We studied fish diversity and distribution and their habitats along these elevation gradients. We found 6,320 specimens from 53 genera. Our analysis for the six most common and widely distributed genera (Astroblepus,Brycon,Bryconamericus,Chaetostoma,PimelodellaandTrichomycterus) underlines the relevance of hydromorphological variables on fish community structure in the Andean montane rivers, whereas human alterations seem to be less significant. These findings could be useful for current management and conservation strategies considering present threats over tropical montane rivers.

This work provides insight into an Andean–Amazonian river system by conducting a comprehensive study of the biodiversity and ecological processes in a poorly studied neotropical freshwater ecosystem. Hacha River in western Colombia harbours a rich and largely unknown biodiversity and is experiencing an increase in anthropogenic impacts from the city of Florencia. Changes in natural habitat characteristics and environmental quality were analysed and related to the distribution of fish and macroinvertebrates. Four environmental quality indices were applied, and concentrations of potential water pollutants were measured. All environmental quality indices used were reliable because they produced similar assessments of the ecological integrity of the study sites and were inversely related to the potential water pollutant concentrations. Fish and macroinvertebrate communities notably changed in response to differences in environmental quality, reinforcing the ecological integrity assessments. Nevertheless, natural gradients that influence fish and macroinvertebrate distributions showed an overlap with changes in environmental quality, thereby confounding the ability to discern the influence of natural and anthropogenic-induced alterations and to confirm an initials hift in fish assemblages due to anthropogenic impacts.

In the Peruvian Amazon, there are few ecological studies on the diversity patterns of aquatic macroinvertebrates, essential for the management of these fluvial ecosystems. In such context, our objective was to determine the taxonomic composition and its relationship with environmental variables along an altitude gradient of the Alto Madre de Dios River, a basin with the potential to register new species. We established 22 stations in an altitudinal range from 398 to 2411 masl and evaluated the water physicochemical characteristics and the fluvial habitat: pH, water temperature (T, ° C), electrical conductivity (CE, μS.cm-1), river width (A, m), depth (P, cm), shadow, current flow speed (m · s-1), and depth. We took macroinvertebrate samples with a 200-μm-mesh-size kick net and identified 56 taxa distributed in the orders Acari, Ephemeroptera, Coleoptera, Diptera, Hemiptera, Megaloptera, Odonata, Plecoptera, Trichoptera, and Decapoda. In the multivariate classification and grouping analysis, four groups of statistically differentiated stations (p <0,05) were classified, mainly by speed and the type of dominant substrate, which explains the abundance and wide distribution of Chironomidae, Baetodes, Traulodes, and Anacroneuria. Macroinvertebrate taxa changed notably along the gradient reporting a greater diversity in areas with middle altitudes and a relationship with environmental variables. Hay pocos estudios ecológicos sobre los patrones de diversidad de los macroinvertebrados acuáticos en la Amazonía peruana, a pesar de ser esenciales para la gestión y manejo de estos ecosistemas fluviales. En este contexto, el objetivo del presente estudio fue determinar su composición taxonómica y su relación con las variables ambientales a lo largo de un gradiente altitudinal del río Alto Madre de Dios, cuenca en donde podrían registrarse nuevas especies. Se establecieron 22 estaciones en un rango altitudinal de 398 a 2.411 m s.n.m., cuantificando las características fisicoquímicas del agua y del hábitat fluvial: pH, temperatura del agua (T, °C), conductividad eléctrica (CE, μS.cm-1), ancho del río (A, m), profundidad (P, cm), sombra y velocidad del flujo de la corriente (m·s-1). Para los muestreos de macroinvertebrados se utilizó una red “de patada” de 200 μm de tamaño de malla. Se identificaron 56 taxones distribuidos en los órdenes Acari, Ephemeroptera, Coleoptera, Diptera, Hemiptera, Megaloptera, Odonata, Plecoptera, Trichoptera y Decapoda. Los análisis multivariados de clasificación y agrupamiento permitieron establecer cuatro grupos de estaciones estadísticamente diferenciadas (p<0,05), principalmente por la velocidad y el tipo de sustrato dominante, lo que explica la abundancia y amplia distribución de Chironomidae, Baetodes, Thraulodes y Anacroneuria. Los taxones de macroinvertebrados cambiaron notablemente a lo largo del gradiente, reportándose una mayor diversidad en zonas con altitudes medias y una relación con las variables ambientales.

The Amazon Basin is home to a great number of Indigenous nationalities that have coevolved with aquatic habitats and fish resulting in a precise traditional ecological knowledge. Nevertheless, this biocultural heritage is threatened by the degradation of rivers and fisheries, and cultural erosion. This research was designed and carried out in the community ofArawanu(Arajuno in Spanish), in the Ecuadorian Amazon, and was requested by the local Kichwa people looking for guidance to gather, systematize and disseminate their ethnoichthyological knowledge. Data collection was carried out through participatory workshops using the pile sorting technique in group dynamics, to identify, name and classify local fish and compile biocultural information about them. From the Linnaean taxonomic perspective, 86 taxa were identified, included in 26 families, and corresponded with 16 Kichwa ethnofamilies and 58 ethnospecies. Five classification levels were identified: (I)Aycha: unique beginner–Animalia kingdom; (II)Yaku Aycha: life form–Pisces superclass; (III)Ayllukuna: ethnofamilies–Linnaean families; (IV) Ethnogenera–Linnaean genus; and (V) Ethnospecies–Linnaean species. A one-to-one correspondence was registered between 35 Kichwa ethnospecies and Linnean species, along with one case of over-differentiation and 21 cases of subdifferentiation (Type A: 7; Type B: 14). The Kichwa ethnoichthyological classification is multidimensional and considers attributes like skin and scales, fishbones and spines, meat quality, body shape, diet, and salience. Of the 58 ethnospecies, 38 were valued for consumption, while medicinal and spiritual uses were mentioned for 40 of them. The participatory work created a forum to discuss the value and threats to ichthyofauna and freshwater systems, enabled the dissemination of their biocultural heritage, and highlighted the cultural relevance of hydro-social ecosystems in their livelihood. The collected information may be critical to adapt local education systems to the Kichwa worldview and to pass down traditional ecological knowledge to future generations, fostering a respectful, careful and conscious relationship between humans and nature. Our results offer a solid and novel information compilation and practical guidance for participatory ethnobiological surveys. Additionally, the ethnobiological and the ethnotaxonomical information establishes the basis to develop sustainable fishing strategies and promote conservation of the local ichthyofauna.