Fish habitat models for a future of novel riverscapes.

Multiple anthropogenic forces have pushed river ecosystems into undesirable states with no clear understanding of how they should be best managed. The advancement of riverine fish habitat models intended to provide management insights has slowed. Investigations into theoretical and empirical gaps to define habitat more comprehensively across different scales and ecological organizations are crucial in managing the freshwater biodiversity crisis. We introduce the concept of novel riverscapes to reconcile anthropogenic forcing, fish habitat, limitations of current fish habitat models, and opportunities for new models. We outline three priority data-driven opportunities that incorporate the novel riverscape concept: fish movement, river behavior, and drivers of novelty that all are integrated into a scale-based framework to guide the development of new models. Last, we present a case study showing how researchers, model developers, and practitioners can work collaboratively to implement the novel riverscape concept.

Three major steps toward the conservation of freshwater and riparian biodiversity.

Freshwater ecosystems and their bordering wetlands and riparian zones are vital for human society and biological diversity. Yet, they are among the most degraded ecosystems, where sharp declines in biodiversity are driven by human activities, such as hydropower development, agriculture, forestry, and fisheries. Because freshwater ecosystems are characterized by strongly reciprocal linkages with surrounding landscapes, human activities that encroach on or degrade riparian zones ultimately lead to declines in freshwater-riparian ecosystem functioning. We synthesized results of a symposium on freshwater, riparian, and wetland processes and interactions and analyzed some of the major problems associated with improving freshwater and riparian research and management. Three distinct barriers are the lack of involvement of local people in conservation research and management, absence of adequate measurement of biodiversity in freshwater and riparian ecosystems, and separate legislation and policy on riparian and freshwater management. Based on our findings, we argue that freshwater and riparian research and conservation efforts should be integrated more explicitly. Best practices for overcoming the 3 major barriers to improved conservation include more and sustainable use of traditional and other forms of local ecological knowledge, choosing appropriate metrics for ecological research and monitoring of restoration efforts, and mirroring the close links between riparian and freshwater ecosystems in legislation and policy. Integrating these 3 angles in conservation science and practice will provide substantial benefits in addressing the freshwater biodiversity crisis.

Tres grandes pasos hacia la conservación de la biodiversidad ribereña y de agua dulce Resumen Los ecosistemas de agua dulce y los humedales y zonas ribereñas que los bordean son vitales para la sociedad y la biodiversidad. Sin embargo, se encuentran entre los ecosistemas más degradados en donde las declinaciones graves de la biodiversidad son causadas por actividades humanas como el desarrollo hidroeléctrico, la agricultura, la silvicultura y las pesquerías. Puesto que los ecosistemas de agua dulce se caracterizan por tener un vínculo recíproco con los paisajes que los rodean, las actividades humanas que invaden o degradan las zonas ribereñas terminan en la declinación del funcionamiento del ecosistema ribereño de agua dulce. Sintetizamos los resultados de un simposio sobre los procesos e interacciones de agua dulce, ribereños y de humedales y analizamos algunos de los principales problemas asociados con la mejora de la investigación y gestión de agua dulce y ríos. Tres barreras claras son la falta de participación de la población local en la investigación y gestión de la conservación, la ausencia de una medición adecuada de la biodiversidad en los ecosistemas de agua dulce y ribereños, y una legislación y política separadas sobre la gestión ribereña y de agua dulce. Con base en nuestros hallazgos, argumentamos que la investigación y los esfuerzos de conservación de agua dulce y ríos deberían integrarse de manera más explícita. Las mejores prácticas para sobreponerse a las tres grandes barreras incluyen un mayor uso sustentable de los conocimientos tradicionales y otras formas de conocimiento, la selección de medidas apropiadas para la investigación ecológica y el monitoreo de los esfuerzos de restauración y la replicación de los vínculos cercanos entre los ecosistemas ribereños y de agua dulce en la legislación y en las políticas. La integración de estos tres ángulos dentro de las ciencias y prácticas de conservación proporcionará beneficios importantes en la manera de abordar la crisis de la biodiversidad de agua dulce.

Modifying and parameterizing the individual-based model inSTREAM for Atlantic salmon and brown trout in the regulated Gullspång River, Sweden.

We modified, parameterized, and applied the individual-based model inSTREAM version 6.1 for lake-migrating populations of landlocked Atlantic salmon (Salmo salar) and brown trout (S. trutta) in a residual flow stretch of the hydropower-regulated Gullspång River, Sweden. This model description is structured according to the TRACE model description framework. Our aim was to model responses in salmonid recruitment to alternative scenarios of flow release and other environmental alterations. The main response variable was the number of large out-migrating juvenile fish per year, with the assumption that individuals are more inclined to out-migrate the larger they get, and that migration is an obligatory strategy. Population and species-specific parameters were set based on local electrofishing surveys, redd surveys, physical habitat surveys, broodstock data as well as scientific literature.•Simulations were set to run over 10 years, with sub-daily time steps, in this spatially and temporally explicit model.•Model calibration and validation of fish growth was done using data on juvenile fish from electrofishing.•The results were found to be sensitive to parameter values for aggregated fish, i.e., "superindividuals" and for the high temperature limit to spawning.

The need for ecocentrism in biodiversity conservation.

Over the past 5 decades, scientists have been documenting negative anthropogenic environmental change, expressing increasing alarm, and urging dramatic socioecological transformation in response. A host of international meetings have been held, but the erosion of biological diversity continues to accelerate. Why, then, has no effective political action been taken? We contend that part of the answer may lie in the anthropocentric ethical premises and moral rhetoric typically deployed in the cause of conservation. We further argue that it is essential to advance moral arguments for biodiversity conservation that are not just based on perceived human interests but on ecocentric values, namely, convictions that species and ecosystems have value and interests that should be respected regardless of whether they serve human needs and aspirations. A broader array of moral rationales for biodiversity conservation, we conclude, would be more likely to lead to effective plans, adopted and enforced by governments, designed to conserve biological diversity. A good place to start in this regard would be to explicitly incorporate ecocentric values into the recommendations that will be made at the conclusion of the 15th meeting of the parties to the Convention on Biological Diversity, scheduled to be held in October 2020.

La Necesidad del Ecocentrismo en la Conservación de la Biodiversidad Resumen Durante las últimas cinco décadas, los científicos han estado documentando el cambio ambiental negativo causado por la actividad humana, expresando cada vez una mayor alarma e insistiendo por una transformación socio-ecológica dramática como respuesta. Se han realizado un número de reuniones internacionales pero la erosión de la diversidad biológica se sigue acelerando. Entonces, ¿por qué no se han tomado acciones políticas efectivas? Sostenemos que parte de la respuesta a esta pregunta puede estar en las premisas éticas antropocéntricas y en la retórica moral que típicamente se despliega para la causa de la conservación. Además, argumentamos que es esencial promover argumentos morales para la conservación de la biodiversidad que no estén solamente basados en los intereses humanos percibidos sino en los valores ecocéntricos, principalmente la convicción de que las especies y los ecosistemas tienen valor e intereses que deberían respetarse sin importar si sirven a las necesidades y aspiraciones humanas. Concluimos que un conjunto más amplio de justificaciones morales para la conservación de la biodiversidad tendría mayor probabilidad de guiar planes efectivos, adoptados y aplicados por los gobiernos, diseñados para conservar la diversidad biológica. Un buen punto de partida al respecto sería la incorporación explícita de los valores ecocéntricos dentro de las recomendaciones que se harán al concluir la decimoquinta reunión de las partes que forman al Convenio sobre la Diversidad Biológica, programada para octubre 2020.

Ice cover affects the growth of a stream-dwelling fish.

Protection provided by shelter is important for survival and affects the time and energy budgets of animals. It has been suggested that in fresh waters at high latitudes and altitudes, surface ice during winter functions as overhead cover for fish, reducing the predation risk from terrestrial piscivores. We simulated ice cover by suspending plastic sheeting over five 30-m-long stream sections in a boreal forest stream and examined its effects on the growth and habitat use of brown trout (Salmo trutta) during winter. Trout that spent the winter under the artificial ice cover grew more than those in the control (uncovered) sections. Moreover, tracking of trout tagged with passive integrated transponders showed that in the absence of the artificial ice cover, habitat use during the day was restricted to the stream edges, often under undercut banks, whereas under the simulated ice cover condition, trout used the entire width of the stream. These results indicate that the presence of surface ice cover may improve the energetic status and broaden habitat use of stream fish during winter. It is therefore likely that reductions in the duration and extent of ice cover due to climate change will alter time and energy budgets, with potentially negative effects on fish production.

Genomics and the challenging translation into conservation practice.

The global loss of biodiversity continues at an alarming rate. Genomic approaches have been suggested as a promising tool for conservation practice as scaling up to genome-wide data can improve traditional conservation genetic inferences and provide qualitatively novel insights. However, the generation of genomic data and subsequent analyses and interpretations remain challenging and largely confined to academic research in ecology and evolution. This generates a gap between basic research and applicable solutions for conservation managers faced with multifaceted problems. Before the real-world conservation potential of genomic research can be realized, we suggest that current infrastructures need to be modified, methods must mature, analytical pipelines need to be developed, and successful case studies must be disseminated to practitioners.