Morphometric relations of freshwater fishes of the Suaza River (Huila Department, Colombia)

The knowledge of freshwater fishes in remote Andean mountains is scarce and restricted to changes of occurrence distribution along a specific gradient. The high number of endemic fish species requires further studies regarding their biology and their conservation status. The present study aims to estimate the length-weight, length- length, and length-girth relations for nine native freshwater fish species representing five families (Loricariidae, Characidae, Heptapteridae, Crenuchidae, and Parodontidae): Chaetostoma thomsoni Regan, 1904; Lasiancistrus caucanus Eigenmann, 1912; Rineloricaria jubata (Boulenger, 1902); Bryconamericus huilae Román- Valencia, 2003; Gephyrocharax melanocheir Eigenmann, 1912; Pimelodella chagresi (Steindachner, 1876); Rhamdia guatemalensis (Quoy et Gaimard, 1824); Characidium fasciatum Reinhardt, 1867; Parodon suborbitalis Valenciennes, 1850. The fishes were collected in the Suaza River (Huila, Colombia). These are the first length-weight relations reported for all these species, mostly endemic to the Colombian Andes. The report also provides the new maximum size for four species

Diagnosing stream ecosystem integrity in the Ordesa-Viñamala Biosphere Reserve, central Spanish Pyrenees

This work studied the ecological integrity of river ecosystems inside the Ordesa-Viñamala Biosphere Reserve, in the central Spanish Pyrenees. Despite its protected status, the Ordesa-Viñamala Biosphere Reserve endures a considerable number of human stresses, so we aimed to evaluate the conservation status of the two river basins inside the protected area: The Gállego River Basin, located inside the transition zone of the protected area, allowing a wide range of human activities; and the Ara River Basin, inside the buffer zone, where only sound ecological practices are authorised. The environmental status of river ecosystems was analysed by studying fish and macroinvertebrate communities, hydrochemical and habitat characteristics and by calculating environmental quality indices. From August to September 2011 a total of 14 sites were sampled. Fish sampling was conducted using an electrofishing gear and macroinvertebrate was sampling by applying the IBMWP and IASPT procedures. Our results showed that, while the Ara River Basin keeps a good ecological integrity, the Gállego River Basin endures important habitat alteration. Trout, the dominant and exclusive species in the Ara River, were absent and replaced by translocated native cyprinids in the Gállego River Basin. This colonisation was explained by the alteration of the stream ecosystems and their homogenisation. The study of macroinvertebrate communities and the diagnosis obtained with the environmental quality indices also enhanced the deficient ecological integrity of some sites in the Gállego River. Our results suggest that the figure of the Biosphere Reserve is not providing an adequate protection to streams inside its boundaries leading to a major degradation of their biological integrity

Fish Ecology of the Alto Madre de Dios River Basin (Peru): Notes on Electrofishing Surveys, Elevation, Palm Swamp and Headwater Fishes

Our study analyzes the distribution of fish communities related to the environmental variables of the Alto Madre de Dios River, an Andean-Amazon watershed of southern Peru, between 300 and 2811 m a.s.l. within the Manu Biosphere Reserve. We provide new ecological and diversity data on fishes for these poorly studied rivers and new data for palm swamp habitats. With electric fishing techniques, we collected a total of 1934 fish specimens belonging to 78 species, 42 genera and 15 families. To assess main patterns of diversity we combined SIMPER and ANOSIM with canonical correspondence analysis to obtain an overview of the community structure of fish and their distribution related to aquatic habitats. Our results show an important shift on fish diversity at 700 m a.s.l. separating headwater and middle-lowland communities. Electrofishing was a hindrance due to the depth, flow and low conductivity of the rivers, but also allowed us to capture fish not observed with other techniques. We also compared the use of elevation with slope as an alternative variable for statistical analysis. Our results show that slope offers a solid and equivalent explanation for fish distribution variability, avoids redundance, and instead of giving geographical data offers ecologically solid information

Gradientes ecológicos y distribución de comunidades de peces en ríos de montaña: de la ecología a la conservación; de los Pirineos a los Andes

River ecosystems integrate all the changes that occur throughout the territory of their basin and for this is why they are among the most threatened and altered ecosystems in the world. This loss of habitat has direct consequences on the organisms inhabiting them. Freshwater fish are the most threatened group of vertebrates on the planet. Therefore, we must prioritize their protection implementing effective management strategies capable to ensure the conservation of riverine habitats and species. Nevertheless, there is a big gap of knowledge involving these ecosystems and biota, hindering their management. This lack of knowledge is especially significant in the Neotropics, where the greatest diversity of freshwater fish of the planet water is found. Unfortunately, these highly biodiverse areas are exposed to great threats that are destroying their habitats. These facts point out the Tropical Andes as a particularly biodiverse but seriously threatened region whose conservation should be prioritized. However, management plans must be based on appropriate ecological studies, providing reliable biological information and guaranteeing the development of appropriate conservation strategies. In the light of this critical knowledge gap, this thesis aims to evaluate the effectiveness of a sampling methodology that aspires to be versatile, inclusive and simple, testing it in different biogeographic contexts. Thus, five river basins (two in the Pyrenees and three in the Tropical Andes) were analyzed conducting electrofishing surveys, collecting aquatic macroinvertebrates, characterizing river habitat and applying environmental quality indices. One of our main goals was to study the freshwater ecological processes and its influence on the distribution of fish communities. Additionally, we evaluated the integrity of river ecosystems, trying to understand the consequences of human impacts on the biota. One of the most common strategies for the protection of ecosystems and species is the creation of protected areas. The Biosphere Reserves aspire to protect biodiversity and promote the sustainable development of the communities inhabiting them. Nevertheless, the scarcity of available biological information and the lack of studies that evaluate the effectiveness of these protected areas may be hindering the successful management and conservation of rivers and fish inside them. Our results point out that, although some Biosphere Reserves are partially fulfilling their protective function, their management strategies should be revised and their action plans adapted to the new available scientific information. Our sampling campaigns provided us with a better understanding of the ecology of poorly known rivers and fish, and the methods proved to reliability to diagnose ecological integrity. Nevertheless, due to time and budged limitations, we could only visit once each of the basins, hindering our interpretation of their complex reality. However, the obtained data allows us to emphasize the urge of prioritizing the protection of the headwaters of the Tropical Andes. They still remain very well preserved, they provide invaluable and irreplaceable ecosystem services and host a large number of fish species endemic to each of the basins. In addition, given the increasing anthropogenic impacts threatening these ecosystems, it is mandatory to delve into ecological studies to understand the natural reference conditions of these rivers, necessary to the appropriate development of management policies and restoration. This urge for knowledge highlights the necessity to continue with exploratory sampling campaigns, aspiring to cover the large knowledge gaps we are facing, and to guarantee the effectivity of the conservation biology. Biodiversity and ecology knowledge are the foundations for protecting nature

Gradientes ecológicos y distribución de comunidades de peces en ríos de montaña: de la ecología a la conservación; de los Pirineos a los Andes

River ecosystems integrate all the changes that occur throughout the territory of their basin and for this is why they are among the most threatened and altered ecosystems in the world. This loss of habitat has direct consequences on the organisms inhabiting them. Freshwater fish are the most threatened group of vertebrates on the planet. Therefore, we must prioritize their protection implementing effective management strategies capable to ensure the conservation of riverine habitats and species. Nevertheless, there is a big gap of knowledge involving these ecosystems and biota, hindering their management. This lack of knowledge is especially significant in the Neotropics, where the greatest diversity of freshwater fish of the planet water is found. Unfortunately, these highly biodiverse areas are exposed to great threats that are destroying their habitats. These facts point out the Tropical Andes as a particularly biodiverse but seriously threatened region whose conservation should be prioritized. However, management plans must be based on appropriate ecological studies, providing reliable biological information and guaranteeing the development of appropriate conservation strategies. In the light of this critical knowledge gap, this thesis aims to evaluate the effectiveness of a sampling methodology that aspires to be versatile, inclusive and simple, testing it in different biogeographic contexts. Thus, five river basins (two in the Pyrenees and three in the Tropical Andes) were analyzed conducting electrofishing surveys, collecting aquatic macroinvertebrates, characterizing river habitat and applying environmental quality indices. One of our main goals was to study the freshwater ecological processes and its influence on the distribution of fish communities. Additionally, we evaluated the integrity of river ecosystems, trying to understand the consequences of human impacts on the biota. One of the most common strategies for the protection of ecosystems and species is the creation of protected areas. The Biosphere Reserves aspire to protect biodiversity and promote the sustainable development of the communities inhabiting them. Nevertheless, the scarcity of available biological information and the lack of studies that evaluate the effectiveness of these protected areas may be hindering the successful management and conservation of rivers and fish inside them. Our results point out that, although some Biosphere Reserves are partially fulfilling their protective function, their management strategies should be revised and their action plans adapted to the new available scientific information. Our sampling campaigns provided us with a better understanding of the ecology of poorly known rivers and fish, and the methods proved to reliability to diagnose ecological integrity. Nevertheless, due to time and budged limitations, we could only visit once each of the basins, hindering our interpretation of their complex reality. However, the obtained data allows us to emphasize the urge of prioritizing the protection of the headwaters of the Tropical Andes. They still remain very well preserved, they provide invaluable and irreplaceable ecosystem services and host a large number of fish species endemic to each of the basins. In addition, given the increasing anthropogenic impacts threatening these ecosystems, it is mandatory to delve into ecological studies to understand the natural reference conditions of these rivers, necessary to the appropriate development of management policies and restoration. This urge for knowledge highlights the necessity to continue with exploratory sampling campaigns, aspiring to cover the large knowledge gaps we are facing, and to guarantee the effectivity of the conservation biology. Biodiversity and ecology knowledge are the foundations for protecting nature

Size spectra and other size-related variables of river fish communities: systematic changes along the altitudinal gradient on pristine Andean streams

The estimation of biodiversity is complex in remote areas like Andean-Amazon piedmont where the lack of knowledge is noticeable and most species have not yet been identified. An alternative to the taxonomical approach to assess biodiversity and community structure is to study the body size structure of the community. The present study aimed to identify systematic changes of the size structure of fish communities along the altitudinal gradient of pristine Andean streams. At the same time, we assessed if size structure of fish communities could be an alternative or complementary approach to traditional taxonomic metrics of ecological assessment. This study was conducted along two rivers of eastern Andean piedmont: Hacha River and Alto Madre de Dios basin. Our analysis showed lower values of total size range, maximum length and number of size classes in the highest places and increasing in lower reaches of the rivers. Concerning abundance size spectra, we found flatter slopes (indicating higher relative abundance of large fish) and lower coefficient of determination (i.e. less linear size spectra) and intercept at y-axis on upstream reaches. On the other hand, fish abundance, species richness and species diversity increasing from upstream to downstream. These systematic changes on size-related variables were similar using both basins together or independently and may be used in future studies as management reference conditions when assessing the effect of perturbations in freshwater ecosystems, while bypassing the error associated with the lack of taxonomic information

Morphometric relations of freshwater fishes of the Suaza River (Huila Department, Colombia)

The knowledge of freshwater fishes in remote Andean mountains is scarce and restricted to changes of occurrence distribution along a specific gradient. The high number of endemic fish species requires further studies regarding their biology and their conservation status. The present study aims to estimate the length-weight, length- length, and length-girth relations for nine native freshwater fish species representing five families (Loricariidae, Characidae, Heptapteridae, Crenuchidae, and Parodontidae): Chaetostoma thomsoni Regan, 1904; Lasiancistrus caucanus Eigenmann, 1912; Rineloricaria jubata (Boulenger, 1902); Bryconamericus huilae Román- Valencia, 2003; Gephyrocharax melanocheir Eigenmann, 1912; Pimelodella chagresi (Steindachner, 1876); Rhamdia guatemalensis (Quoy et Gaimard, 1824); Characidium fasciatum Reinhardt, 1867; Parodon suborbitalis Valenciennes, 1850. The fishes were collected in the Suaza River (Huila, Colombia). These are the first length-weight relations reported for all these species, mostly endemic to the Colombian Andes. The report also provides the new maximum size for four species