Mechanisms, models, and management of invasive species and soil biogeochemical process in prairie pothole wetlands

Statement of Problem:

The US Department of the Interior manages hundreds of thousands of acres of wetland habitat in National Wildlife Refuges (NWRs), Waterfowl Production Areas (WPAs), and National Parks (NPs) across multiple states in the Northern Great Plains, Prairie Pothole Region (PPR). Complex interactions among wetland vegetation, hydrology, and soil processes provide the ecological foundation for wetland resources such as habitat for waterfowl, wildlife and floral biodiversity, nutrient and flood water retention, and climate mitigation.  Over recent decades, the PPR has experienced extreme changes in wetland habitat due to extended periods of drought and deluge, extensive changes in land use related to agriculture, and the proliferation of invasive species. These dramatic changes in climate and land use/cover diminish wetland resources.

One of the primary changes in land cover in PPR wetlands has been the proliferation of Typha x glauca (invasive cattail), a hybrid cross between a native and exotic species.  Invasive cattail creates dense monotypic stands, thick layers of leaf litter, and extensive belowground rhizomatous systems, which alters or reduces native faunal and floral biodiversity.  The shallow, eutrophic wetlands of the PPR are especially vulnerable to being choked out by invasive cattail. Despite the widespread impact of cattail on both public and private wetlands, its current and future distributions, the pathways of spread, or effective control measures are still unknown.

Why this Research is Important: 

Changes in climate and land use have an immense impact on wetland soils and associated biogeochemical processes.  Previous work has shown that PPR wetlands are biogeochemical hotspots, with rapid turnover and transport rates of carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) though the soil-water-atmosphere continuum.  These biogeochemical processes result in C and N uptake from, and losses to, the atmosphere as greenhouse gases (GHGs).  Furthermore, these processes are directly affected by changes in wetland habitat due to climate variability and management (e.g., wetland drainage/consolidation) and indirectly affected by changes in wetland vegetation such as cattail invasion.  Although biogeochemical cycling in PPR wetlands is significant enough to impact regional, national and global GHG budgets, there are no landscape-scale models estimating baseline GHG emissions or potential impacts of future land use/land cover and climate scenarios.

A better understanding of the impacts of changes in land use/land cover and climate on the mechanistic interactions between invasive cattails, wetland hydrology and biogeochemical processes are needed to develop spatially-explicit, landscape models.  Combining field observations and remotely-sensed data analyses to develop such models could provide land managers and policy makers with information needed to understand, monitor, and anticipate changes in wetland resources under various management, land-use, and climate scenarios.

Objective(s): 

The overarching goals of this project are to improve our understanding of wetland vegetation, hydrology and soil processes to predict changes that may occur under various land-use/cover and climate scenarios to help inform DOI land management and policy decisions.

Objective 1:  Current and future distribution of invasive cattail

Objective 2:  Cattail-management effects on wetland vegetation, hydrology and soil processes

Objective 3:  Past, baseline and future GHG emissions and C sequestration from PPR wetlands