When the river runs dry: human and ecological values of dry riverbeds

Steward, Alisha L.; Schiller, Daniel von; Tockner, Klement; Marshall, Jonathan; Bunn, Stuart E.

doi:10.1890/110136

Cited by 258 publications

(263 citation statements)

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“…Despite recent progress in understanding the role of dry channels as important habitats for terrestrial arthropods (e.g. Wishart, 2000;Larned et al, 2007;Steward et al, 2011;Steward et al, 2012;Corti and Datry, 2015;Corti et al, 2013;Corti and Datry, 2014), the terrestrial phase is not yet integrated into bioassessment strategies. We also need to consider the entire hydrological cycle in order to allow a more comprehensive assessment of the ecological status of Mediterranean NPRS .…”

Section: Biological Research Challengesmentioning

confidence: 99%

Non-perennial Mediterranean rivers in Europe: Status, pressures, and challenges for research and management

Skoulikidis

Sabater

Datry

et al. 2017

Science of The Total Environment

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213

134

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Non-perennial rivers and streams (NPRS) cover N 50% of the global river network. They are particularly predominant in Mediterranean Europe as a result of dry climate conditions, climate change and land use development. Historically, both scientists and policy makers underestimated the importance of NRPS for nature and humans alike, mainly because they have been considered as systems of low ecological and economic value. During the past decades, diminishing water resources have increased the spatial and temporal extent of artificial NPRS as well as their exposure to multiple stressors, which threatening their ecological integrity, biodiversity and ecosystem services. In this paper, we provide a comprehensive overview of the structural and functional characteristics of NPRS in the European Mediterranean, and discuss gaps and problems in their management, concerning their typology, ecological assessment, legislative and policy protection, and incorporation in River Basin Management Contents lists available at ScienceDirect Science of the Total Environment j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i t o t e n vPlans. Because NPRS comprise highly unstable ecosystems, with strong and often unpredictable temporal and spatial variability -at least as far as it is possible to assess -we outline the future research needs required to better understand, manage and conserve them as highly valuable and sensitive ecosystems. Efficient collaborative activities among multidisciplinary research groups aiming to create innovative knowledge, water managers and policy makers are urgently needed in order to establish an appropriate methodological and legislative background. The incorporation of NPRS in EU-Med River Basin Management Plans in combination with the application of ecological flows is a first step towards enhancing NPRS management and conservation in order to effectively safeguard these highly valuable albeit threatened ecosystems.

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Section: Biological Research Challengesmentioning

confidence: 99%

Non-perennial Mediterranean rivers in Europe: Status, pressures, and challenges for research and management

Skoulikidis

Sabater

Datry

et al. 2017

Science of The Total Environment

Self Cite

213

134

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“…For example, in California, Mazor et al [118] demonstrated acceptable performance of current biomonitoring indices such as the Southern California Index of Biotic Integrity (IBI) for many intermittent streams. Moreover, innovative approaches, such as one based on terrestrial fauna [119,120] are being developed.…”

Section: Biomonitoring In Highly Variable Systemsmentioning

confidence: 99%

High Variability Is a Defining Component of Mediterranean-Climate Rivers and Their Biota

Cid

Bonada

Carlson

et al. 2017

Water

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Abstract:Variability in flow as a result of seasonal precipitation patterns is a defining element of streams and rivers in Mediterranean-climate regions of the world and strongly influences the biota of these unique systems. Mediterranean-climate areas include the Mediterranean Basin and parts of Australia, California, Chile, and South Africa. Mediterranean streams and rivers can experience wet winters and consequent floods to severe droughts, when intermittency in otherwise perennial systems can occur. Inter-annual variation in precipitation can include multi-year droughts or consecutive wet years. Spatial variation in patterns of precipitation (rain vs. snow) combined with topographic variability lead to spatial variability in hydrologic patterns that influence populations and communities. Mediterranean streams and rivers are global biodiversity hotspots and are particularly vulnerable to human impacts. Biomonitoring, conservation efforts, and management responses to climate change require approaches that account for spatial and temporal variability (including both intra-and inter-annual). The importance of long-term data sets for understanding and managing these systems highlights the need for sustained and coordinated research efforts in Mediterranean-climate streams and rivers.

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“…The alternatives therefore are entering dormancy until the conditions become again favorable, or being able to colonize the particular habitat from the outside. During the stream contraction process, pools are formed in the deeper parts of the stream, where lotic communities are gradually replaced by lentic others and even semiaquatic or terrestrially-derived biota (Stanley et al, 1997;Steward et al, 2012;Timoner et al, 2014a). In these pools, attached communities are progressively replaced by free-living (tychoplanktonic; Fazi et al, 2013) communities, and finally by subaerial communities when the drying is complete.…”

Section: Biofilms In Temporary Streamsmentioning

confidence: 99%

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

Sabater

Timoner

Borrego

et al. 2016

Front. Environ. Sci.

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Temporary streams are characterized by the alternation of dry and wet hydrological phases, creating both a harsh environment for the biota as well as a high diversity of opportunities for adaptation. These systems are mainly microbial-based during several of these hydrological phases, and those growing on all solid substrata (biofilms) accordingly change their physical structure and community composition. Biofilms experience large decreases in cell densities and biomass, both of bacteria and algae, during dryness. Algal and bacterial communities show remarkable decreases in their diversity, at least locally (at the habitat scale). Biofilms also respond with significant physiological plasticity to each of the hydrological changes. The decreasing humidity of the substrata through the drying process, and the changing quantity and quality of organic matter and nutrients available in the stream during that process, causes unequal responses on the biofilm bacteria and algae. Biofilm algae are affected faster than bacteria by the hydric stress, and as a result the ecosystem respiration resists longer than gross primary production to the increasing duration of flow intermittency. This response implies enhancing ecosystem heterotrophy, a pattern that can be exacerbated in temporary streams suffering of longer dry periods under global change.Keywords: biofilm, dry-rewetting cycle, temporary, intermittency, bacteria, algae, Mediterranean THE RELEVANCE OF TEMPORARY STREAMS IN THE WORLDFlow intermittency is part of the natural hydrology for streams and rivers, especially in arid and semi-arid landscapes. Temporary streams, or those that cease to flow at some points in space and time along their course, are a large fraction of many river networks, basically in tributaries of small order, but also in segments in the middle and lower parts of river networks. The number of temporary streams has been probably underestimated , as it appears from the application of novel on-site sensors, advances in remote sensing, and new modeling approaches. Flow intermittency has been estimated to account for 69% of first-order streams below 60 • , and up to 34% of larger order rivers (Raymond et al., 2013). Flow intermittency produces periodic or eventrelated loss of hydrologic connectivity between stream compartments, with consequences for all the processes ongoing in a waterway. Thus, flow intermittency triggers a chain of cascading effects eventually affecting water chemistry and biogeochemistry, as well as biodiversity, and ultimately community structure and ecosystem functioning.The direct implications of climate change and anomalous climatic events on flow regime are behind of the increasing temporality of many streams and rivers. Complex planetary scale processes, as well as local processes, may justify these situations. Anomalies such as the El Niño

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When the river runs dry: human and ecological values of dry riverbeds

Cited by 258 publications

References 50 publications

Non-perennial Mediterranean rivers in Europe: Status, pressures, and challenges for research and management

Non-perennial Mediterranean rivers in Europe: Status, pressures, and challenges for research and management

High Variability Is a Defining Component of Mediterranean-Climate Rivers and Their Biota

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

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