RESUMEN
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.
RESUMEN
Bioturbators shape their environment with considerable consequences for ecosystem processes. However, both the composition and the impact of bioturbator communities may change along climatic gradients. For burrowing animals, their abundance and composition depend on climatic and other abiotic components, with ants and mammals dominating in arid and semiarid areas, and earthworms in humid areas. Moreover, the activity of burrowing animals is often positively associated with vegetation cover (biotic component). These observations highlight the need to understand the relative contributions of abiotic and biotic components in bioturbation in order to predict soil-shaping processes along broad climatic gradients. In this study, we estimated the activity of animal bioturbation by counting the density of holes and the quantity of bioturbation based on the volume of soil excavated by bioturbators along a gradient ranging from arid to humid in Chile. We distinguished between invertebrates and vertebrates. Overall, hole density (no/ 100 m2) decreased from arid (raw mean and standard deviation for invertebrates: 14 ± 7.8, vertebrates: 2.8 ± 2.9) to humid (invertebrates: 2.8 ± 3.1, vertebrates: 2.2 ± 2.1) environments. However, excavated soil volume did not follow the same clear geographic trend and was 300-fold larger for vertebrates than for invertebrates. The relationship between bioturbating invertebrates and vegetation cover was consistently negative whereas for vertebrates both, positive and negative relationships were determined along the gradient. Our study demonstrates complex relationships between climate, vegetation and the contribution of bioturbating invertebrates and vertebrates, which will be reflected in their impact on ecosystem functions.
