Spatiotemporal scaling of North American continental interior wetlands: implications for shorebird conservation

Within interior North America, erratic weather patterns and heterogeneous wetland complexes cause wide spatio-temporal variation in the resources available to migrating shorebirds. Identifying the pattern-generating components of landscape-level resources and the scales at which shorebirds respond to these patterns will better facilitate conservation efforts for these species. We constructed descriptive models that identified weather variables associated with creating the spatio-temporal patterns of shorebird habitat in ten landscapes in north-central Oklahoma. We developed a metric capable of measuring the dynamic composition and configuration of shorebird habitat in the region and used field data to empirically estimate the spatial scale at which shorebirds respond to the amount and configuration of habitat. Precipitation, temperature, solar radiation and wind speed best explained the incidence of wetland habitat, but relationships varied among wetland types. Shorebird occurrence patterns were best explained by habitat density estimates at a 1.5 km scale. This model correctly classified 86 % of shorebird observations. At this scale, when habitat density was low, shorebirds occurred in 5 % of surveyed habitat patches but occurrence reached 60 % when habitat density was high. Our results suggest scale dependence in the habitat-use patterns of migratory shorebirds. We discuss potential implications of our results and how integrating this information into conservation efforts may improve conservation strategies and management practices

Effect of Copper, Irgarol and Atrazine on Epiphytes Attached to Artificial Devices for Coastal Ecotoxicology Bioassays

Toxic effects of copper, atrazine and irgarol were evaluated on epiphytes attached to mimes (artificial devices that mimic the morphology of seagrasses) in order to check sensitivity of this biological group. Tube-dwelling diatoms were the major component of the epiphyte community. Superoxide dismutase activity was enhanced by exposure to 25 and 50 μg L-1 of atrazine; the organism generates this antioxidant response to prevent cellular damage by removing reactive oxygen substances produced by oxidative stress. The measurement of antioxidant enzymatic activity in epiphytes could be a useful technique for ecotoxicology monitoring in marine coastal environments. © Springer Science+Business Media New York 2013.The research was funded by the project PHYTOBIOMARK (CTM2009-10563/MAR).Peer Reviewe

Do Environmental Stream Classifications Support Flow Assessments in Mediterranean Basins?

The final publication is available at http://dx.doi.org/10.1007/s11269-012-0104-3Natural flow regimes are of primary interest in designing environmental flows and therefore essential for water management and planning. The present study discriminated natural hydrologic variation using two different environmental classifications (REC-Segura and WFD-ecotypes) and tested their agreement with an a posteriori (hydrologic) classification in a Spanish Mediterranean basin (the Segura River, SE Spain). The REC-Segura was developed as a two-level hierarchical classification based on environmental variables that influence hydrology (climate and source-of-flow). The WFD-ecotypes were developed by the Spanish Ministry for the Environment to implement the Water Framework Directive (WFD) using hierarchical hydrologic, morphologic and physicochemical variables. The climate level in the REC-Segura broadly described the hydrologic pattern observed along the NW-SE aridity gradient of the basin. However, source-of-flow (defined by karstic geology) was only able to discriminate variation in flow regimes within one climatic category. The WFD-ecotypes, despite incorporating hydrologic variables, did not fully discriminate hydrologic variation in the basin. Ecotypes in tributary streams located in dry or semiarid climates embrace different flow regimes (both perennial and intermittent). There was little agreement between environmental and hydrologic classifications. Therefore, the authors advise against the use of environmental classifications for the assessment of environmental flows without first testing their ability to discriminate hydrologic patterns.We would like to thank the University of Murcia for its financial support to Oscar Belmar through a pre-doctoral grant, the Hydrographic Confederation of the Segura for providing the precipitation data as well as the SIMPA model, and the Euromediterranean Institute of Water for its support to the project "Hydrological classification of the rivers and streams in the Segura Basin and associated macroinvertebrate communities".Belmar, O.; Velasco, J.; Martinez-Capel, F.; Peredo Parada, MM.; Snelder, T. (2012). Do Environmental Stream Classifications Support Flow Assessments in Mediterranean Basins?. Water Resources Management. 26(13):3803-3817. doi:10.1007/s11269-012-0104-3S38033817261

Cleanup of atrazine-contaminated soils: ecotoxicological study on the efficacy of a bioremediation tool with Pseudomonas sp. ADP

Purpose To mitigate the environmental effects of atrazine, one of the cleanup strategies available is based on the use of atrazine-degrading bacteria. This work aimed to evaluate the efficacy of a previously developed bioremediation tool for atrazine-contaminated soils (combining bioaugmentation with Pseudomonas sp. ADP, hereafter designated as P. ADP, and biostimulation with citrate) on both soil habitat and retention functions, by performing ecotoxicological tests with standard soil and aquatic species. Materials and methods Soil microcosms (incorporating earthworms, collembolans, and plants) were spiked with three doses of Atrazerba FL, an atrazine commercial formulation: the recommended dose (RD; 2 L/ha), 10×RD and 20×RD to simulate overuse/accidental spills scenarios. The experiment included two main groups of treatments: (1) microcosms sprayed solely with Atrazerba, i.e., nonbioremediated soils (NB) and (2) microcosms sprayed with both Atrazerba and the bioremediation tool (addition of P. ADP plus citrate), i.e., bioremediated soils (B). Control microcosms with no herbicide or P. ADP plus citrate addition were also set up. Besides soil chemical analysis, the following ecotoxicological endpoints were assessed to monitor bioremediation: plant biomass production, earthworm reproduction, microalgae growth (in eluates— collected 5 and 10 days after the bioremediation treatment— and leachates—collected on day seven), and cladoceran reproduction (in soil eluates). Results In NB soils, all Atrazerba doses induced a severe reduction in plant biomass production, and no effects were found for earthworm’s reproduction. Eluates and leachates obtained from the NB soils caused deleterious effects on both microalgae growth and cladoceran reproduction. Chemical analysis showed that atrazine degradation was faster in B soils than in the correspondent NB soils. Data from toxicity tests indicated that test organism performance was enhanced in B soils and respective eluates and leachates, compared to the NB samples. In fact, for soils contaminated with 10 and 20×RD Atrazerba doses, plant biomass production was significantly higher in the B soils than in the correspondent NB soils. Regarding the effects of soil bioremediation on the toxicity of soil eluates and leachates, for the soil contaminated with 10×RD of Atrazerba, over a 5-day treatment period, both microalgae growth and cladoceran reproduction were significantly higher in water extracts obtained from the B soils when compared with the NB extracts and also similar to the control. By the contrary, for the highest Atrazerba dose tested (20×RD), no significant differences were found on the toxicity of B and NB eluates toward both aquatic test organisms. However, for this same dose, after 7 days, microalgae growth was higher in B than in the NB leachates and similar to the control. Yet, after a longer bioremediation period of 10 days, eluates were also no longer toxic to both aquatic organisms. Discussion Based on atrazine soil chemical analysis, one can state that the addition of P. ADP plus citrate to the atrazine-contaminated soils was clearly effective in promoting atrazine biodegradation. In addition, ecotoxicological data support the efficacy of this cleanup tool. Indeed, results showed that the bioremediation treatment resulted in a relevant reduction on soil toxicity to a plant (approximately 100% and 72% of control, respectively, for 10× RD and 20×RD contaminated soils). In addition, 5 days of P. ADP activity were enough to annul atrazine toxic effects toward microalgae and cladocerans in eluates obtained from the soil contaminated with 10×RD of Atrazerba. For 20×RD, an effective detoxification of eluates was achieved only after a longer bioremediation period of 10 days. Conclusions The ecotoxicity tests proved not only the effective detoxification of bioremediated soils in 10 days but also the potential ability to concurrently reduce atrazine contamination of water compartments due to leaching and/ or run-off events, to levels that may no longer be hazardous to ecosystems. Due to the worldwide continued use of atrazine/triazine-based herbicidal formulations, further studies viewing the optimization of this cost-effective cleanup tool at larger scales (mesocosm and real field scenarios) and testing of other commercial formulations containing mixtures of atrazine/triazine and other active ingredient are still needed so that bioremediation can be used as a valuable tool to reduce herbicide toxicity in contaminated land.publishe