Linking Remote Sensing and Process-Based Models to Assess Land Use and Climate Change Impacts on Plant Invasion in Great Lakes Coastal Wetlands

Laura L Bourgeau-Chavez, Michigan Tech Research Institute, lchavez@mtu.edu (Presenter)
William Currie, University of Michigan, wcurrie@umich.edu
Deborah E Goldberg, University of Michigan, degold@umich.edu
David Hyndman, Michigan State University, hyndman@cns.msu.edu
Kenneth Elgersma, University of Northern Iowa, kenneth.elgersma@uni.edu
Mary Ellen Miller, Michigan Tech Research Institute, marymill@mtu.edu
Michael Battaglia, Michigan Tech Research Institue, mjbattag@mtu.edu
Sarah Endres, Michigan Tech Research Institute, slendres@mtu.edu
Nancy H French, Michigan Tech Research Institute, nhfrench@mtu.edu

Spread of invasive plant species in the coastal wetlands of the Great Lakes is degrading wetland habitat, decreasing biodiversity, and decreasing ecosystem services. An understanding of the mechanisms of invasion is crucial to gaining control of this growing threat. To better understand the effects of land use and climatic drivers on the vulnerability of coastal zones to invasion, as well as to develop an understanding of the mechanisms of invasion, research is being conducted that integrates field studies, process-based ecosystem (MONDRIAN) and hydrogeochemical (LHM) models, and remote sensing.

Spatial data from remote sensing is needed to parameterize the hydrological model and to test the outputs of the linked models. Several new remote sensing products tuned to wetlands and the ecosystems of the Great Lakes are providing important physiological, biochemical, and landscape information to parameterize and verify models. This includes: 1) a multi-date hybrid radar-optical technique to delineate stands of invasives, as well as natural wetland cover types and land use; 2) using radar to map seasonally inundated areas not hydrologically connected; and 3) developing new algorithms to estimate leaf area index (LAI) using Landsat. A coastal map delineating wetland types including monocultures of the invaisive cattails (Typha spp.) and Phragmites (Phragmites australis) was created using satellite radar (ALOS PALSAR, 20 m resolution) and optical data (Landsat 5, 30 m resolution) fusion from multiple dates in a Random Forests classifier. These maps provide spatial information on the distribution of the invasive plants to use in verification of the linked models.

Elevated nitrogen (N) inflows are believed to facilitate the spread of large-stature invasive plants (Typha spp. and Phragmites australis) that reduce biodiversity and have complex effects on other ecosystem services including wetland N retention and carbon (C) accretion. The LHM (Landscape Hydrology Model) was used to simulate the effects of land use on N flows in streams, rivers, and groundwater throughout the Lower Peninsula of Michigan. The hydroperiods and N loading rates simulated by LHM were used as inputs to the MONDRIAN model of wetland community-ecosystem processes to estimate invasion risk and other ecosystem services in coastal wetlands around the Michigan coast. The linked models produced threshold behavior in the success of invasive plants in response to N loading, with the threshold ranging from ca. 8 to 12 g N/m2 y, depending on hydroperiod. Plant invasions increased wetland productivity 3-fold over historically oligotrophic native communities, decreased biodiversity but slightly increased wetland N retention. Regardless of invasion, elevated N loading resulted in significantly enhanced rates of C accretion, providing an important region-wide mechanism of C storage. The linked models predicted a general pattern of greater invasion risk in the southern basins of lakes Michigan and Huron relative to northern areas. The basic mechanisms of invasion have been partially validated in field mesocosms constructed for this project. The general regional patterns of increased invasion risk have been validated through field campaigns and the coastal wetland maps.

Presentation: 2015_Poster_BourgeauChavez_112_136.pdf (797k)

Presentation Type:  Poster

Session:  Theme 2: Landscapes to coasts: understanding Earth system connections   (Mon 1:30 PM)

Associated Project(s): 

• Bourgeau-Chavez, Laura: Linking Remote Sensing and Process-Based Models to Better Understand the Influence of Land Use and Climate Changes on Great Lakes Coastal Wetlands ...details

Poster Location ID: 112