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Soil Moisture in the Wetland Habitat

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Principal Investigator/Project Leader: 
Co-Principal Investigator/Co-Project Leader: 
Department of Project: 
Department of Geosciences
Project Description: 

Total wetland area in the U.S. has been in precipitous decline since the 1900's, and although recent decades have slowed the decline and advocated strongly for the services and economic benefits (not to mention ecological benefits!) these lands provide, still much more work needs to be done to preserve existing wetlands and promote restoration of impaired ones. Specifically, new research indicates that the approach of destroying a wetland in one area and building a new one elsewhere is largely ineffective, because the full function of the system takes many decades or even hundreds of years to develop fully, if at all (e.g. Ballantine et al. 2009 and 2012). Curiously, most restoration efforts only extend post-restoration monitoring for a period of three years or less, a timeframe that is woefully insufficient to see real change develop. Because this site was a well-developed wetland for tens of thousands of years before farming activities commenced a hundred or so years ago, this site may benefit from a jump start back to a more natural state. And there are many locations like this in Massachusetts that may follow suit if economic conditions and incentives are aligned. Natural and restored wetlands are among the most biodiverse ecosystems present in Massachusetts, providing unique habitat for species ranging from insects and endangered native fishes to coastal birds and songbirds, and plants which thrive in environments that range from completely saturated year-round to dry. Because this niche environment is crucially important for ecosystem services (including, but not limited to verdant habitat and food supply for a large diversity of plant, animal and insect species, water filtration, slowing and spreading of floodwaters, limiting erosion, storage of carbon and other nutrients, temperature buffering, pollinator habitat and forage lands, and water storage), significant attention has been paid to conserving and restoring wetlands and their optimum function wherever possible. One of the most basic, defining metrics of a wetland is, as the name implies, its wetness. The relative water content in the soil can be assessed in a variety of ways, and this quantity alone is important for reasons beyond wetland function. Specifically, for a wetland to become established and remain functional independently, sufficient water must be present throughout the year to favor wetland plants and animals, which thrive in wet environments but are unlikely to outcompete invasives or other species in drier regimes. We foresee a continued interest in wetland restoration in Massachusetts and predict that measurable metrics to assess the success of such restoration efforts are desired. To that end, we propose developing a series of tools to measure soil moisture and subsurface thermal regimes to monitor change over time. These measurements will occur at points in time, points in space, or distributed in space, and wherever possible, complementary methods would be applied together to improve the accuracy of each estimate. Specifically, for this work, there are six main methods we will usee: hydraulic property measurements, Distributed Temperature Sensing (DTS, which uses fiber-optic cables to sense temperature along long transects), long-term soil moisture monitoring (buried probes at multiple depths at three permanent stations on the site), gravimetric soil moisture sampling (ground-truth measurements), soil moisture probe campaigns (to establish proxy relationships), and geophysical measurement campaigns (for deeper interpretation and important large scale imagery).

We will begin this project at a test bed location ideally suited for this work: Tidmarsh Farms in Plymouth, MA was a cranberry farm since the 1900's, and has been left fallow for the last 4 years. In August or September 2015, and ambitious restoration project will begin to restore freshwater wetland function to 250+ acres of this former peatland. The landowners are keenly interested in infusing the restoration design with sound and cutting edge science, as well as ample scientific observation of the restoration process. Two mechanisms are in development for this dissemination: The Living Observatory will curate active participation in scientific research and climate change observation, and the Massachusetts Audubon Society (MassAudubon) plans to acquire the property and manage it as a public nature sanctuary. Scientific inquiry, the restoration process, and the function of the changing wetland landscape will reach the public in novel and exciting ways through the channels above.

Environmental Conservation topics: