Efecto de la introducción de peces en la conservación de anfibios y crustáceos de lagos de alta montaña

Este capítulo contiene 16 páginas, 11 figuras y una tabla.La introducción de especies invasoras es un aspecto determinante relacionado con el cambio global que incide en la conservación de los ecosistemas. Actualmente, la gestión para la conservación (e.g., Parques Nacionales) se enfrenta a las incertidumbres creadas con la aparición de nuevas especies introducidas por el hombre, sobre todo las que pasan a desarrollar un papel clave en los ecosistemas. Para poder tomar políticas de gestión correctas es necesario conocer con detalle cuál es el impacto de estas especies y su papel en el ecosistema. Los lagos del Parque Nacional de Aigüestortes y Estany de Sant Maurici han sufrido la introducción de peces llegando a tener en la actualidad un 62% de lagos afectados. El objetivo general del proyecto fue estudiar el efecto de la introducción de peces en las comunidades planctónicas y bentónicas de los lagos de alta montaña del Parque Nacional. Para llevar a cabo tal objetivo nos centramos en el estudio de dos grupos de organismos indicadores, los crustáceos del plancton y los anfibios. Los resultados obtenidos nos muestran que los peces son el factor principal que explica la presencia de la mayor parte de las especies de anfibios en los lagos. En cambio el efecto de los peces sobre la presencia de crustáceos planctónicos se limita a las especies de mayor tamaño, afectando principalmente la biodiversidad y especialmente la abundancia de los crustáceos, que disminuye con la presencia de peces. La desaparición de los anfibios en los lagos con peces provoca un efecto en cascada cambiando biomasa y composición de las algas y procariotas (bacterias y arqueas) que viven en la superfície de las piedras del litoral de los lagos.Peer reviewe

Eliminación de peces introducidos como medida de restauración de lagos de alta montaña

E. Carrillo, J. Ninot, T. Buchaca and M. Ventura. Blanes, LIFE+ LIMNOPIRINEUS Technical OfficeEntre los objetivos del proyecto LIFE+ LimnoPirineus (2014-2019) figuraban la restauración ecológica de ocho lagos pirenaicos y la recuperación o mejora de las poblaciones de diversas especies de interés comunitario de estos lagos, mediante la erradicación o el control intensivo de peces introducidos de hasta cuatro especies. En la mayor parte de lagos el objetivo operativo ha sido la erradicación, mientras que tan solo en uno de ellos el objetivo pasaba simplemente por llevar a cabo un control intensivo hasta alcanzar al menos una reducción del 75 % de la población inicial. A finales de 2019, estos objetivos se han alcanzado completamente para cinco de los lagos de actuación, mientras que en los otros tres lagos están cerca de alcanzarse, cosa que sucederá probablemente antes de finales de 2020. Se han puesto a punto métodos de extracción de peces basados en la combinación de hasta tres técnicas de captura principales: redes, trampas y pesca eléctrica. Se demuestra que la erradicación de los peces es factible en muchos lagos de alta montaña con una inversión suficiente en medios materiales y humanos, y con una adecuada planificación de las operaciones. Cuando no es factible la erradicación, el control intensivo mediante un esfuerzo sostenible en el tiempo es también una alternativa que cabe considerar a medio plazo.Peer reviewe

Temperature variability, predation pressure and zooplankton composition in Pyrenean high mountain lakes

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Large negative effect of non-native trout and minnows on Pyrenean lake amphibians

Este artículo contiene 10 páginas, 4 figuras, 2 tablas.High mountain lakes are mostly naturally fishless ecosystems that have received numerous trout introductions over the world. Extensive studies mostly developed in west North America have shown a large negative effect of these introductions on amphibians, although no extensive studies are available from other continents such as Europe. Fish were also introduced extensively in the Pyrenees (southern Europe), mainly trout for angling and minnows for their use as live bait for fishing trout. We studied the effect of non-native trout and minnows on the occurrence of amphibian species inhabiting Pyrenean lentic habitats. Chi-square tests and Generalized Additive Models were applied on a dataset of 12 environmental descriptors from 1739 water bodies surveyed from 2006 to 2016. After accounting for environmental characteristics we found a large negative effect of non-native trout and minnows on Pyrenean amphibians. Trout was negatively associated with four of the six studied species. Since minnows were only introduced in trout present lakes, they were only significant for Rana temporaria, the most distributed amphibian in the area. None of the palatable amphibians have been able to recolonise the lakes where minnow remain as the only fish species indicating a strong negative effect. Minnow is the non-native fish with a higher introduction rate in the mountain range indicating that it might be a threat for other species in the future. Therefore, the control of trout stocking and minnow release in high mountain lakes is necessary to preserve European and worldwide amphibian populations in these ecosystems.Economic support was provided by the Spanish Government projects Fundalzoo (CGL2010-14841) and Invasivefish (427/2011) and by the European Commission LIFE+ project LimnoPirineus (LIFE13 NAT/ES/001210).Peer reviewe

Impacte del barb roig en els prats submergits d'isoetes lacustris dels estanys dels Pirineus

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Non-native Minnows Threaten Quillwort Populations in High Mountain Shallow Lakes

Este artículo contiene 11 páginas, 8 figuras, 5 tablas.Submersed aquatic plants are a key component of shallow, clear water lakes contributing to primary production and water quality. High mountain lakes are naturally fishless although invasive trout and most recently minnows have been introduced causing a major impact on fauna richness. The Pyrenean high mountain range has preserved soft-water oligotrophic boreal isoetids in their southern limit of distribution but the recent fish introduction is a potential factor of stress that needs to be addressed. We here work under the hypothesis that due to contrasting ecological features, trout will not be heavily affecting quillwort populations while minnows will have a stronger effect on zooplankton and zoobenthos that will promote algal growth and reduce light availability for the underwater meadows. Ten Pyrenean shallow lakes representative of three scenarios -fishless, with trout and with minnows-, were sampled for meadow structure, water column and benthic environment characterization in mid-summer 2015 and 2016. Quillwort biomass allocation (above vs. belowground), epiphytic load, and composition of the algal community (abundant cyanobacteria) differed in the presence of minnows. In trout lakes biomass allocation and epiphytic load were average and the algal community composed by chlorophytes and diatoms as in fishless lakes. Biomass ratio was close to thresholds of negative buoyancy in minnow lakes indicating that meadows were at risk of uprooting and consequent de-vegetation. Total and soluble carbohydrates were lower and the sporangia contained significantly less reserves to constrain growth and expansion in the presence of minnows. Lake scenarios were coupled to physicochemical differences with low light, high phosphorus and Chl-a (mesotrophia) in minnow lakes, while trout and fishless lakes remained oligotrophic. This is the first study assessing the impact of non-native fish on soft-water isoetids from mountain lakes and shows that minnows are a major threat to quillworts. The impaired light environment (from epiphytic algal overgrow and water column Chl-a) entails consequent regression (i.e., no recruitment) and de-vegetation (uprooting) of themeadows. Since soft-water oligotrophic mountain lakes are protected under the Habitats Directive, some action needs to be urgently implemented not only to preserve quillworts but to the overall ecological integrity of the lakes.This work was funded by the European Commission LIFE+ project LimnoPirineus (LIFE13 NAT/ES/001210), EU H2020 eLTER ref. 999452014-EAA, and by Grup de Recerca de Canvis Ambientals GECA (SGR-DGR), Generalitat de Catalunya. SGR 1249. 2017-2020.Peer reviewe

Non-native Minnows Threaten Quillwort Populations in High Mountain Shallow Lakes

Este artículo contiene 11 páginas, 8 figuras, 5 tablas.Submersed aquatic plants are a key component of shallow, clear water lakes contributing to primary production and water quality. High mountain lakes are naturally fishless although invasive trout and most recently minnows have been introduced causing a major impact on fauna richness. The Pyrenean high mountain range has preserved soft-water oligotrophic boreal isoetids in their southern limit of distribution but the recent fish introduction is a potential factor of stress that needs to be addressed. We here work under the hypothesis that due to contrasting ecological features, trout will not be heavily affecting quillwort populations while minnows will have a stronger effect on zooplankton and zoobenthos that will promote algal growth and reduce light availability for the underwater meadows. Ten Pyrenean shallow lakes representative of three scenarios -fishless, with trout and with minnows-, were sampled for meadow structure, water column and benthic environment characterization in mid-summer 2015 and 2016. Quillwort biomass allocation (above vs. belowground), epiphytic load, and composition of the algal community (abundant cyanobacteria) differed in the presence of minnows. In trout lakes biomass allocation and epiphytic load were average and the algal community composed by chlorophytes and diatoms as in fishless lakes. Biomass ratio was close to thresholds of negative buoyancy in minnow lakes indicating that meadows were at risk of uprooting and consequent de-vegetation. Total and soluble carbohydrates were lower and the sporangia contained significantly less reserves to constrain growth and expansion in the presence of minnows. Lake scenarios were coupled to physicochemical differences with low light, high phosphorus and Chl-a (mesotrophia) in minnow lakes, while trout and fishless lakes remained oligotrophic. This is the first study assessing the impact of non-native fish on soft-water isoetids from mountain lakes and shows that minnows are a major threat to quillworts. The impaired light environment (from epiphytic algal overgrow and water column Chl-a) entails consequent regression (i.e., no recruitment) and de-vegetation (uprooting) of themeadows. Since soft-water oligotrophic mountain lakes are protected under the Habitats Directive, some action needs to be urgently implemented not only to preserve quillworts but to the overall ecological integrity of the lakes.This work was funded by the European Commission LIFE+ project LimnoPirineus (LIFE13 NAT/ES/001210), EU H2020 eLTER ref. 999452014-EAA, and by Grup de Recerca de Canvis Ambientals GECA (SGR-DGR), Generalitat de Catalunya. SGR 1249. 2017-2020.Peer reviewe

Factors of surface thermal variation in high-mountain lakes of the Pyrenees

Este artículo contiene 19 páginas, 6 figuras, 1 tabla.Thermal variables are crucial drivers of biological processes in lakes and ponds. In the current context of climate change, determining which factors better constrain their variation within lake districts become of paramount importance for understanding species distribution and their conservation. In this study, we describe the regional and short-term interannual variability in surface water temperature of high mountain lakes and ponds of the Pyrenees. And, we use mixed regression models to identify key environmental factors and to infer mean and maximum summer temperature, accumulated degree-days, diel temperature ranges and three-days’ oscillation. The study is based on 59 lake-temperature series measured from 2001 to 2014. We found that altitude was the primary explicative factor for accumulated degree-days and mean and maximum temperature. In contrast, lake area showed the most relevant effect on the diel temperature range and temperature oscillations, although diel temperature range was also found to decline with altitude. Furthermore, the morphology of the catchment significantly affected accumulated degree-days and maximum and mean water temperatures. The statistical models developed here were applied to upscale spatially the current thermic conditions across the whole set of lakes and ponds of the Pyrenees.The authors want to aknowledge the Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya and the European Social Fund for the doctoral scholarship FI (2015FI_B_01147) given to the first author, that has allowed this work. The projects provided by the Spanish Government projects; Fundalzoo (CGL2010-14841) and Invasivefish (427/2011) and by the European Commission LIFE+ project LimnoPirineus (LIFE13 NAT/ES/001210), and also the last project of the Spanish Government, FUNBIO (RTI2018-096217- B-I00) supported this research.With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI).Peer reviewe

Response of the aquatic invertebrate community to the eradication of an exotic invasive fish 30 years after its introduction into an Iberian alpine lake

Este artículo contiene 21 páginas, 8 figuras, 5 tablas.In Lake Grande de Peñalara, an originally fishless small high mountain lake in the Central Iberian Peninsula, brook trout (Salvelinus fontinalis) was introduced in the 1970s, and then eradicated 30 years later using gillnets. In this study, we investigated the time-course and changes in macroinvertebrates and zooplankton communities, before and after the eradication, by studying their richness and several biological and ecological traits of macroinvertebrates. Macroinvertebrates richness increased from 13 taxa coexisting with fish, up to a maximum of 27 taxa after the eradication. Rare groups usually affected by fish predation, e.g. swimmers in surface and open waters, showed high dispersal and recolonization capabilities, while those with burrowing, interstitial or crawler habits maintained their presence, and even with the presence of fish given their advantage of hiding from being directly sighted by fish. Taxa with affinities for rare habitats within the lake (e.g. macrophyte beds) occasionally appeared 4–6 years after eradication. In contrast, zooplankton assemblage did not significantly change in richness in the 10 years after eradication. No new species of cladocerans or copepods appeared after fish removal, but 4 new rotifer taxa appeared and 5 disappeared. This was apparently more related to a change in water quality or trophic status as a consequence of the fish removal than to the direct effect of fish removal on rotifers. Zooplankters were significantly smaller, on average, before fish eradication rather than later, indicating that the community responded to the change in predation pressure.This work has been supported by the National Park of Sierra de Guadarrama (Regional Government of Madrid). Work by A.C. is currently funded by the project CLIMAWET (CGL201569557-R).Peer reviewe

Efecte de diferents pressions de depredació en l'estructura i la composició del zooplancton

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