Browsing by Subject "Restoration"

ABSTRACTThis thesis is offers exilic texts as the basis for restoration for communities traumatized by displacement. The scriptural focus for the thesis is Jeremiah 30-33, the Book of Restoration. The purpose of the thesis is to provide tools for inner-city pastors to navigate the opportunities and challenges of displacement caused by gentrification. The thesis is fueled by the contrast between numerous studies that report the benefits of gentrification versus its ills experienced as a pastoral witness of the machinery of displacement in the northwest quadrant of Washington, D.C. In Dr. Ellen Davis’ work on Jeremiah, she shows Jeremiah’s painful growth into his prophetic role. This growth occurs through laments or “protests addressed to God” thus making it possible to “lay claim to realistic hope.” This birth of hope is in the beginning of the book in Jeremiah 1:10, “See, today I appoint you over nations and over kingdoms, to pluck up and to pull down, to destroy and to overthrow, to build and to plant,” with building and planting as themes for Jeremiah 30-33. Dr. Davis further explicates hope’s placement. Hope finds a concrete place economically through Jeremiah’s land purchase (Chapter 32:6-15) and socially through community building (chapters 30 and 31). Building upon this work, my thesis concludes that Book of Restoration provides a relevant and effective model of restoration for today’s church.

Invasive species are rapidly expanding in riparian wetlands while concurrently anthropogenic causes are increasing nitrogen (N) into these ecosystems. Microstegium vimineum (Microstegium) is a particularly abundant invasive grass in the Southeast United States. To evaluate impacts of Microstegium on both plant diversity and N cycling in a riparian floodplain, paired plots of Microstegium hand-weeded and unweeded were established for three years. Plots without Microstegium increased from 4 to 15 species m-2 and 90% of the newly establishing species were native. The Microstegium community accumulated approximately half the annual N in biomass of the diverse community, 5.04 versus 9.36 g-N m-2 year-1, respectively (p=0.05). Decomposition and release of N from Microstegium detritus was much less than in the diverse community, 1.19 versus 5.24 g-N m-2 year-1. Rates of soil N mineralization estimated by in-situ incubations were relatively similar in all plots. While Microstegium invasion appears to greatly diminish within-ecosystem circulation of N through the under-story plants, it might increase ecosystem N losses through enhanced denitrification (due to lower redox potentials under Microstegium plots). Microstegium removal ceased in the fourth growing season and formerly weeded plots increased to 59% (± 11% SE) Microstegium cover and species richness decreased to <8 species m-2.

To learn how Microstegium responds to increased N, we conducted a greenhouse competition experiment between Microstegium and four native plants across an N gradient. There was a unique competition outcome in each species combination, yet Microstegium was most dominant in the high levels of N.

Last, we disturbed a floodplain similar to wetland restoration disturbance and tracked available N. We also established a native community of plants with and without Microstegium in three levels of N. Disturbance to the floodplain dramatically increased inorganic N, especially in the form of NO₃ which was five times higher in the disturbed floodplain than the undisturbed floodplain. N levels remained elevated for over a year. Microstegium was N responsive, but did not show negative effects to the planted vegetation until the second year. Ironically, restoration activities are increasing available N, and favoring invasive species which in turn detracts from restoration success.

Coastal ecosystems and the valuable services they provide have and continue to be degraded by anthropogenic stressors across the globe. Conservation efforts to mitigate deleterious impacts have largely failed at aiding ecosystem recovery such that restoration has become a predominant method of stemming the loss of critical habitats and the communities they support. Globally, it is estimated that 29% of seagrass beds have been lost or converted, and this translates to trillions of dollars lost in ecosystem services as well as commercial and recreational prospects. In this dissertation, I evaluate how ecological interactions can alter restoration trajectories and shift community dynamics. Namely, I focus on facilitative and trophic interactions among seagrasses, bivalves, and the associated nekton and mesograzer communities propagate through seagrass ecosystems. To do this, I use a combination of scientific literature review, surveys, and manipulative field experiments to apply ecological theories of species interactions in seagrass restoration and conservation. Reviews of the coastal restoration research reveal a paucity of studies that consider biological interactions as important factors that may determine restoration success (Chapter 1). Because foundation species, such as seagrasses, can promote the success and survival of numerous other organisms through facilitation, I further tested if and how a facilitation cascade among seagrass beds and pen clams, Atrina rigida, may affect local diversity and ecosystem functions (Chapter 2). Since studies have, in fact, shown that positive interactions can also enhance restoration of coastal foundation species, I investigated in how the inclusion of intra- and interspecific interactions can affect seagrass restoration from seed and adult shoots. Finally, given that top-down influences can also affect bivalve abundances and seagrass productivity, I explored how large predator removals (via exclusion stockades) may shift seagrass community structure and propagate onto primary producers.

In these studies, I find that facilitative interactions can promote not only the success and yield of bivalve populations, but that in some instances, bivalves can also, in turn, facilitate the growth of seagrasses. Similarly, alteration to diversity at higher trophic levels can have positive top-down impacts on bivalve abundances despite alterations to mesopredator abundances. Whereas biological interactions have historically been ignored in the restoration literature, my dissertation research makes the argument that consideration and incorporation of species interactions is necessary for understanding the ecology that underlies the stability, recovery, and resilience of coastal ecosystems.