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8 results on '"Cavaliere, Emily"'

1. An integrated assessment of impacts to ecosystem services associated with prairie pothole wetland drainage quantifying wide-ranging losses

Author

Whitfield, Colin J., Cavaliere, Emily, Baulch, Helen M., Clark, Robert G., Spence, Christopher, Shook, Kevin R., He, Zhihua, Pomeroy, John W., and Wolfe, Jared D.

Abstract

In many regions, a tradeoff exists between draining wetlands to support the expansion of agricultural land, and conserving wetlands to maintain their valuable ecosystem services. Decisions about wetland drainage are often made without identifying the impacts on the services these systems provide. We address this gap through a novel assessment of impacts on ecosystem services via wetland drainage in the Canadian prairie landscape. Draining pothole wetlands has large impacts, but sensitivity varies among the indicators considered. Loss of water storage increased the magnitude of median annual flows, but absolute increases with drainage were higher for larger, less frequent events. Total phosphorus exports increased in concert with streamflow. Our analysis suggested disproportionate riparian habitat losses with the first 30% of wetland area drained. Dabbling ducks and wetland-associated bird abundances respond strongly to the loss of small wetland ponds; abundances were predicted to decrease by half with the loss of only 20%–40% of wetland area. This approach to evaluating changes to key wetland ecosystem services in a large region where wetland drainage is ongoing can be used with an economic valuation of the drainage impacts, which should be weighed against the benefits associated with agricultural expansion.

Published
2024
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5. Winter in two phases: Long‐term study of a shallow reservoir in winter.

Author

Cavaliere, Emily and Baulch, Helen M.

Subjects
*WINTER, *CHLOROPHYLL, *PHYSICAL training & conditioning
Abstract

Climate‐driven decreases in ice‐cover duration have the potential to impact lake ecosystems, yet we have only partial understanding of the effects of winter conditions on physical, chemical, and biological properties of lakes. We used 39 years of monitoring data to examine under‐ice changes in nutrients, oxygen, and phytoplankton in a shallow drinking‐water reservoir. Two phases of winter were identified. Early winter was characterized by declining oxygen. In this phase, there were increases in specific conductance and concentrations of ammonium (NH4+‐N) and soluble reactive phosphorus (SRP). In the month prior to ice off these trends reversed themselves and phytoplankton began to increase. Specific conductance declined as meltwater entered the lake. Nutrients (SRP and NH4+‐N) declined, concurrent with increases in chlorophyll a and oxygen during late winter. This work demonstrates that chemical and biotic changes through winter are highly time dependent and differ between early and late winter phases. The late winter phase is often unstudied because of unsafe ice conditions, but here, the "spring" bloom commonly occurs in late winter under ice. The phases of winter, which are likely driven by changes in light, must be considered as we work to understand how diverse lakes will respond to declining periods of ice cover, and what drives differences in the spring ecology of diverse ice‐covered lakes. [ABSTRACT FROM AUTHOR]

Published
2021
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7. Elwha River sediments: phosphorus dynamics under diverse environmental conditions

Author

Cavaliere, Emily

Abstract

Two large dams on the Elwha River, on the Olympic Peninsula in Washington State, are scheduled for removal in 2011. Removing the Glines Canyon Dam will release up to 10.6 million cubic meters of sediment from Lake Mills. The sediments will be exposed to new physical and chemical conditions and be redistributed throughout the ecosystem. In the summer of 2008, sediment samples were taken from the above-water delta and the submerged lake bottom of Lake Mills to identify initial physical and chemical characteristics relating to the variable status of phosphorus in the sediments. The sediments were analyzed for different forms of phosphorus (P), amorphous iron (Fe), carbon (C), nitrogen (N), and particle size. The lake sediments had greater concentrations of all elements analyzed and had smaller mean particle size compared to the delta sediments. A two-week incubation of sediments under various environmental conditions indicated P release was not affected by atmosphere type. For delta sediments, P release was greater in freshwater than saltwater throughout the incubation, while for lake sediments this occurred only initially. Overall, the magnitude of P release was similar for the two sediment types. An isotherm study performed in conjunction with the incubation study revealed that both the lake and delta sediments could immobilize large quantities of added P, but lake sediments maintained dissolved P concentrations at half the level of delta sediments. Managers could use the information found in this study to help understand the phosphorus release and immobilization patterns in sediments after dam removal.

Published
2010
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