Abstract

Wetlands created or restored to replace natural wetland often fail to achieve functional equivalence and delivery of similar ecosystem services, especially with regard to plant community structure. In these young ecosystems, native emergent plants may not successfully compete with invasive species that are more rapid colonizers and capable of taking advantage of disturbed systems. This susceptibility to invasion and lack of resilience is exacerbated under conditions of high nutrient availability or extreme variations in weather as a result of climate change. Management of invasive plants in wetlands typically involves costly chemical and mechanical control measures, necessitating development of cost-effective and less environmentally damaging management practices to control invasive plants and ensure successful outcomes of restoration efforts. The addition of carbon to wetland soil has been previously shown to decrease nitrogen availability by promoting microbial processes that immobilize N. We hypothesized that by decreasing nitrogen availability through addition of organic matter, that we would increase the competitive ability of native species that are better adapted to low nutrient environments. To test this prediction, carbon, in the form of readily available leaf litter compost, was added to two created emergent freshwater wetlands in Perinton, NY that differ in hydrology. Compost was applied in large (2 x 30 m) transects and the vegetation community composition and soil characteristics monitored throughout the growing seasons of 2015 and 2016. At the wetter site, compost addition was crossed with manual removal of the dominant invasive plant, Typha sp. Weather patterns during the course of this study were variable, including a severe drought during the 2016 growing season. Compost amendments improved soil quality by increasing soil organic matter, soil moisture and bulk density and at the drier site increased the cover of native species. During the drought in 2016, the plant community shifted towards more resilient species, especially the invasive grass P. arundinacea, with compost addition providing a minor buffer for the extreme lack of precipitation. The seasonal and interannual variation observed in this study demonstrates the importance of frequent monitoring and implementation of multiple management strategies in created wetlands to ensure desirable outcomes, especially in light of the changing climate.

Library of Congress Subject Headings

Constructed wetlands--Ecology; Ecosystem services; Soil biochemistry; Endemic plants--Conservation; Plants--Effect of carbon on

Publication Date

8-6-2021

Document Type

Thesis

Student Type

Graduate

Degree Name

Environmental Science (MS)

Department, Program, or Center

Thomas H. Gosnell School of Life Sciences (COS)

Advisor

Anna Christina Tyler

Advisor/Committee Member

Carmody McCalley

Advisor/Committee Member

Elizabeth Hane

Campus

RIT – Main Campus

Plan Codes

ENVS-MS

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