Do protected areas conserve neotropical freshwater fishes? A case study of a biogeographic province in Venezuela

¿Las áreas protegidas conservan los peces continentales neotropicales? un caso de estudio para una provincia biogeográfica en Venezuela La efectividad de las áreas protegidas para la conservación de peces continentales es limitada ya que generalmente estas no son congruentes con los patrones regionales de la riqueza y distribución de las especies de peces. Como caso de estudio comparamos la riqueza, distribución y abundancia de la ictiofauna en ríos costeros de una provincia biogeográfica de Venezuela para determinar su estatus de conservación. Además, también estimamos la efectividad de las áreas protegidas para la conservación de la ictiofauna según la riqueza y distribución de especies en diferentes unidades fisiográficas y afluentes. La ictiofauna (72 spp., ~30% endémicas; ~10% amenazadas) se distribuyó acorde con la orografía, cuencas y unidades fisiográficas. La mayoría de áreas protegidas evidenciaron una efectividad baja para la conservación de peces, principalmente porque eran muy pequeñas o incluían sólo fragmentos de afluentes o cuencas, o porque estaban localizadas en zonas de montaña, donde la diversidad de especies era mínima. Para proteger con eficacia adecuada a a los peces continentales de la provincia, las áreas protegidas existentes deberían ser modificadas y expandidas. Palabras clave: Biodiversidad acuática, Provincia biogeográfica, Parques nacionales, Ríos costeros.The effectiveness of protected areas to conserve freshwater fishes is limited because these areas are not usually congruent with regional patterns of fish species richness and distribution. We compared the richness, distribution and abundance of coastal freshwater fishes in a biogeographic province of Venezuela to determine their conservation status. We also estimated the relevance of existing protected areas in conserving fishes in different physiographic units and tributaries by evaluating species richness and distribution. The ichthyofauna (72 spp., ~30% endemic, ~10% threatened) was distributed according to orography, drainage and physiographic units. Most protected areas had limited effectiveness for fish conservation, mainly because they were too small or included only fragments of tributaries or drainages, or because they were located only in highland drainages where species diversity was minimal. To adequately protect freshwater fishes in this province the existing protected areas should be modified and expanded. Key words: Aquatic biodiversity, Biogeographic province, National parks, Coastal rivers.¿Las áreas protegidas conservan los peces continentales neotropicales? un caso de estudio para una provincia biogeográfica en Venezuela La efectividad de las áreas protegidas para la conservación de peces continentales es limitada ya que generalmente estas no son congruentes con los patrones regionales de la riqueza y distribución de las especies de peces. Como caso de estudio comparamos la riqueza, distribución y abundancia de la ictiofauna en ríos costeros de una provincia biogeográfica de Venezuela para determinar su estatus de conservación. Además, también estimamos la efectividad de las áreas protegidas para la conservación de la ictiofauna según la riqueza y distribución de especies en diferentes unidades fisiográficas y afluentes. La ictiofauna (72 spp., ~30% endémicas; ~10% amenazadas) se distribuyó acorde con la orografía, cuencas y unidades fisiográficas. La mayoría de áreas protegidas evidenciaron una efectividad baja para la conservación de peces, principalmente porque eran muy pequeñas o incluían sólo fragmentos de afluentes o cuencas, o porque estaban localizadas en zonas de montaña, donde la diversidad de especies era mínima. Para proteger con eficacia adecuada a a los peces continentales de la provincia, las áreas protegidas existentes deberían ser modificadas y expandidas. Palabras clave: Biodiversidad acuática, Provincia biogeográfica, Parques nacionales, Ríos costeros

The spatial scale of density-dependent growth and implications for dispersal from nests in juvenile Atlantic salmon

By dispersing from localized aggregations of recruits, individuals may obtain energetic benefits due to reduced experienced density. However, this will depend on the spatial scale over which individuals compete. Here, we quantify this scale for juvenile Atlantic salmon (Salmo salar) following emergence and dispersal from nests. A single nest was placed in each of ten replicate streams during winter, and information on the individual positions (±1 m) and the body sizes of the resulting young-of-the-year (YOY) juveniles was obtained by sampling during the summer. In six of the ten streams, model comparisons suggested that individual body size was most closely related to the density within a mean distance of 11 m (range 2–26 m). A link between body size and density on such a restricted spatial scale suggests that dispersal from nests confers energetic benefits that can counterbalance any survival costs. For the four remaining streams, which had a high abundance of trout and older salmon cohorts, no single spatial scale could best describe the relation between YOY density and body size. Energetic benefits of dispersal associated with reduced local density therefore appear to depend on the abundance of competing cohorts or species, which have spatial distributions that are less predictable in terms of distance from nests. Thus, given a trade-off between costs and benefits associated with dispersal, and variation in benefits among environments, we predict an evolving and/or phenotypically plastic growth rate threshold which determines when an individual decides to disperse from areas of high local density

Combining literature-based and data-driven fuzzy models to predict brown trout (salmo trutta l.) spawning habitat degradation induced by climate change

[EN] A fuzzy rule-based system combining empirical data on hydraulic preferences and literature information on temperature requirements was used to foresee the brown trout (Salmo trutta L.) spawning habitat degradation induced by climate change. The climatic scenarios for the Cabriel River (Eastern Iberian Peninsula) corresponded to two Representative Concentration Pathways (4.5 and 8.5) for the short (2011¿2040) and mid (2041¿2070) term horizons. The hydraulic and hydrologic modelling were undertaken with process-based numerical models (i.e., River2D© and HBV-light) while the water temperature was modelled by assembling the predictions of three machine learning techniques (M5, Multi-Adaptive Regression Splines and Support Vector Regression). The predicted rise in the water temperature will not be compensated by the more benign lower flows. Consequently, the suitable spawning habitat will be reduced between 15.4¿48.7%. The entire population shall suffer the effects of climate change and will probably be extirpated from the downstream segments of the river.The study has been partially funded by the IMPADAPT project (CGL2013-48424-C2-1-R) with Spanish MINECO (Ministerio de Economía y Competitividad) and FEDER funds and by the Confederación Hidrográfica del Júcar (Spanish Ministry of Agriculture, Food and Environment). The authors thank AEMET and UC for the data provided for this work (dataset Spain02). Finally, we are grateful to the colleagues who worked in the field and in preliminary data analyses; especially Marcello Minervini (funded by the EU programme of Erasmus Traineeships, at the Dept. of Hydraulic Engineering and Environment, Universitat Politècnica de València).Muñoz Mas, R.; Marcos-García, P.; Lopez-Nicolas, A.; Martínez-García, F.; Pulido-Velazquez, M.; Martinez-Capel, F. (2018). Combining literature-based and data-driven fuzzy models to predict brown trout (salmo trutta l.) spawning habitat degradation induced by climate change. Ecological Modelling. 386:98-114. https://doi.org/10.1016/j.ecolmodel.2018.08.012S9811438

Distinctive insular forms of threespine stickleback (Gasterosteus aculeatus) from western Mediterranean islands

Neutral and adaptive variation among populations within a species is a major component of biological diversity and may be pronounced among insular populations due to geographical isolation and island specific evolutionary forces at work. Detecting and preserving potential evolutionary significant units below the species rank has become a crucial task for conservation biology. Combining genetic, phenotypic and ecological data, we investigated evolutionary patterns among the enigmatic threespine stickleback populations from western Mediterranean islands, all of which are threatened by habitat deterioration and climate change. We find indications that these populations derive from different genetic lineages, being genetically highly distinct from the stickleback of mainland Europe and the northern Atlantic as well as from each other. Mediterranean island stickleback populations are also phenotypically distinct from mainland populations but interestingly stickleback from Iceland have converged on a similar phenotype. This distinctive island stickleback phenotype seems to be driven by distinct selective regimes on islands versus continents. Overall, our results reveal the status of western Mediterranean island stickleback as evolutionarily distinct units, important for conservation of biodiversity