Invertebrate and microbial responses to inundation in an ephemeral river reach in New Zealand: effects of preceding dry periods

Larned, Scott T.; Datry, Thibault; Robinson, Christopher T.

doi:10.1007/s00027-007-0930-1

Cited by 83 publications

(122 citation statements)

References 55 publications

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“…Declines in the diversity and abundance of invertebrates emerging from sediments as the duration of drying increases have been observed in several studies (e.g. Larned et al 2007;Datry et al 2012). Also, Jenkins and Boulton (2007) found that for microinvertebrate egg banks, drying for a period greater than 10-20 years resulted in marked declines in species richness.…”

Section: Introductionmentioning

confidence: 78%

“…Decanting was repeated at days 20 and 30. A 30 day duration was chosen as sufficient to stimulate hatching and emergence in most species, based on similar studies (Jenkins and Boulton 2007;Larned et al 2007;Chester and Robson 2011;Datry et al 2012). These studies all used similar methods of inundation with non-chlorinated water, decanting and filtering with the exception that, as in Jenkins and Boulton (2007), samples were not aerated because the sediments were from lentic rather than lotic habitats.…”

Section: Laboratory Experimentsmentioning

confidence: 99%

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Fringing trees may provide a refuge from prolonged drying for urban wetland invertebrates

2016

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Climate change is causing prolonged drying in many seasonal wetlands, including urban wetlands, potentially affecting aquatic invertebrates that take refuge in wetland sediment during dry periods and thereby threatening wetland biodiversity. We collected sediment from two habitats: open water (OW) and fringing trees (FT), in eight urban wetlands after seasonal inundation had ended. Both habitats are inundated during winter-spring and dry in summer-autumn. Each sediment sample was divided into subsamples. One set of subsamples were inundated in the laboratory to test the hypothesis that emerging invertebrate assemblages would differ between OW and FT sediments. Another set of subsamples was dried, stored for a year, and inundated to test the hypothesis that prolonged drying would reduce the abundance and taxa richness of emerging invertebrates. The composition of emerging invertebrate assemblages differed between habitats, with more amphibious species found in FT sediment. Invertebrate responses to prolonged drying and storage varied among species: for some, effects depended on habitat type, while others delayed emergence or showed no response. Microcrustacean abundance was unaffected by drying, suggesting that their productivity during refilling may resist drier water regimes. Surface temperatures of dry sediment are cooler beneath FT, and this sediment has higher organic matter, holds more water and is less dense than OW sediment; and FT sediment remained cooler than OW sediment in the laboratory, despite the absence of shading. Fringing trees may therefore provide a refuge for some freshwater invertebrates relying on dormant stages in the sediment to survive drying in urban wetlands.

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Section: Introductionmentioning

confidence: 78%

Section: Laboratory Experimentsmentioning

confidence: 99%

Fringing trees may provide a refuge from prolonged drying for urban wetland invertebrates

2016

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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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223

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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“…Such effects are partly explained by changes in abiotic processes driving LLD, including leaching of soluble compounds and physical abrasion (Bärlocher, 1992). However, the most critical aspect of emersion periods lies in the physiological stress and spatial confinement (i.e., humid sediment patches and leaf litter refuges (Amalfitano et al, 2007 andYlla et al, 2010)) imposed on aquatic organisms that results in marked changes in the community structure and activity dynamics of microbial decomposers and invertebrate detritivores (Larned et al, 2007, Datry, 2012and Foulquier et al, 2015. Moreover, terrestrial invertebrates colonizing the river during droughts (Adis andJunk, 2002 andDatry, 2016) can eventually outcompete strictly aquatic organisms and modify the decomposition of leaf litter accumulated in dry river beds.…”

Section: Introductionmentioning

confidence: 99%

Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition

et al. 2016

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Highlights• The combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition (LLD) were assessed.• TBZ applied alone had no significant effect on LLD.• Drought strongly impacted the microbial LLD process and led to cascading effects on Gammarus feeding.• Structural and functional effects increased when drought and TBZ were applied simultaneously. AbstractLoss of biodiversity and altered ecosystem functioning are driven by the cumulative effects of multiple natural and anthropogenic stressors affecting both quantity and quality of water resources. Here we performed a 40-day laboratory microcosm experiment to assess the individual and combined effects of drought and the model fungicide tebuconazole (TBZ) on leaf litter decomposition (LLD), a fundamental biogeochemical process in freshwater ecosystems. Starting out from a worst-case scenario perspective, leaf-associated microbial communities were exposed to severe drought conditions (four 5-day drought periods alternated with 4-day immersion periods) and/or a chronic exposure to TBZ (nominal concentration of 20 µg L−1). We assessed the direct effects of drought and fungicide on the structure (biomass, diversity) and activity (extracellular enzymatic potential) of fungal and bacterial assemblages colonizing leaves. We also investigated indirect effects on the feeding rates of the amphipod Gammarus fossarum on leaves previously exposed to drought and/or TBZ contamination. Results indicate a stronger effect of drought stress than fungicide contamination under the experimental conditions applied. Indeed, the drought stress strongly impacted microbial community structure and activities, inhibiting the LLD process and leading to cascading effects on macroinvertebrate feeding. However, despite the lack of significant effect of TBZ applied alone, the effects of drought on microbial functions (i.e., decrease in LLD and in enzymatic activities) and on Gammarus feeding rates were more pronounced when drought and TBZ stresses were applied together. In a perspective of ecological risk assessment and ecosystem management for sustainability, these findings stress the need for deeper insight into how multiple stressors can affect the functioning of aquatic ecosystems and associated services.

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Invertebrate and microbial responses to inundation in an ephemeral river reach in New Zealand: effects of preceding dry periods

Cited by 83 publications

References 55 publications

Fringing trees may provide a refuge from prolonged drying for urban wetland invertebrates

Fringing trees may provide a refuge from prolonged drying for urban wetland invertebrates

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

Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition

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