Dams or barriers are among the most significant anthropogenic threats to global freshwater ecosystems, although they provide invaluable services for shipping, hydropower generation, flood protection, and storage of drinking and irrigation water. River fragmentations due to dams and barriers lead the aquatic landscape into isolated river sections, resulting in hydromorphological discontinuities along longitudinal or lateral gradients. Fragmented river habitats are unstable. They experience uncertain disturbances in both time and space with random and complex hydrological and environmental processes, such as water flow, particulate matter sedimentation, reservoir regulation, and terrestrial input. The diversity, composition, functionality, and activity of microbial communities are important indicators of river ecosystem functions and services. Yet, river fragmentations are likely to disrupt and reconstruct microbial communities, redirecting the patterns of biogeochemical cycles of biogenic elements. Methodology, such as mathematical models, is still limited to describing and elucidating microbial processes under changing hydrological environments in the fragmented rivers. Thus, how do the riverine microbial communities and ecosystem functions respond to the fragmentation in rivers? This Research Topic represents a collective focus on microbial ecology, functional diversity, and new microbial modeling in fragmented rivers. We wish to present new findings in community assembly mechanisms, biotic interactions, functional diversity, and ecosystem functioning responses to the river fragmentations. New perspectives will also provide us with deep insights into the ecological effects of river fragmentation. This Research Topic aims to present the original research articles and reviews to provide new findings on microbial diversity and ecosystem functioning in fragmented rivers worldwide. We welcome original research, reviews, mini-reviews, opinions, methods, hypotheses and theories, and perspectives. The directions include but are not limited to the following aspects: - The continuum of the microbial community in responses to dams or barriers. - Novel microbial community assembly mechanisms, functional traits, and biotic interactions in fragmented rivers at local, regional, and global scales. - Functional genes, functional groups, and functional diversity in driving biogenic element cycles. - Mathematical modeling in aquatic microbial ecology.

Intermittent Rivers and Ephemeral Streams: Ecology and Management takes an internationally broad approach, seeking to compare and contrast findings across multiple continents, climates, flow regimes, and land uses to provide a complete and integrated perspective on the ecology of these ecosystems. Coupled with this, users will find a discussion of management approaches applicable in different regions that are illustrated with relevant case studies. In a readable and technically accurate style, the book utilizes logically framed chapters authored by experts in the field, allowing managers and policymakers to readily grasp ecological concepts and their application to specific situations. Provides up-to-date reviews of research findings and management strategies using international examples Explores themes and parallels across diverse sub-disciplines in ecology and water resource management utilizing a multidisciplinary and integrative approach Reveals the relevance of this scientific understanding to managers and policymakers

This book is about phylogenetic diversity as an approach to reduce biodiversity losses in this period of mass extinction. Chapters in the first section deal with questions such as the way we value phylogenetic diversity among other criteria for biodiversity conservation; the choice of measures; the loss of phylogenetic diversity with extinction; the importance of organisms that are deeply branched in the tree of life, and the role of relict species. The second section is composed by contributions exploring methodological aspects, such as how to deal with abundance, sampling effort, or conflicting trees in analysis of phylogenetic diversity. The last section is devoted to applications, showing how phylogenetic diversity can be integrated in systematic conservation planning, in EDGE and HEDGE evaluations. This wide coverage makes the book a reference for academics, policy makers and stakeholders dealing with biodiversity conservation.

Severely increasing anthropic pressure on natural water bodies sets a societal context where it is urgent to better understand the role of microbial biodiversity in aquatic ecosystem dynamics and resilience to perturbations. Micro-organisms regulate the chemical composition of the biosphere, influence climates, recycle nutrients, and decompose pollutants. The diversity of microbial communities and their ecological and metabolic functions are being explored in a variety of natural ecosystems, including extreme environments. Because of technical constraints, microbiologists have focused their efforts mainly on prokaryotes. In the environment, and particularly in aquatic ecosystems, the diversity and dynamics of microbial eukaryotes are still poorly understood. Among the new paradigms and challenges constantly emerging in aquatic sciences, probing the unexplored reservoir of novel ‘species’, genes, and metabolic pathways from microbial eukaryotes offers, perhaps, the most exciting research opportunity for the future. These were discussed during the topical session # 11 of the ASLO 2009 aquatic sciences meeting held at Nice, France, through a combination of invited and selected talks and posters. This book brings together part of these talks and presents contributions on ‘disregarded’ microbial eukaryote diversity and its ecological potential in aquatic ecosystems. We hope that this collection of papers will greatly expand our knowledge of the roles of eukaryotic microbes in aquatic ecosystems and will serve as a basis for significant research in the future. We believe that the decade to come promises exciting ecology on the interactions between microbial diversity, hidden genes and functions, and food web dynamics in aquatic systems.