Special Sessions
Sponsored by the Geomorphology Specialty Group
Association of American Geographers 103rd Annual Meeting
San Francisco, California, April 17-21.

Environmental and Ecological Restoration I

Paper Session 3101
Thursday, 4/19/07, from 8:00 AM - 9:40 AM

Sponsorship(s):

Biogeography Specialty Group
Geomorphology Specialty Group

Organizer(s):

Joy A. Fritschle - University of Connecticut
Melinda Daniels - University of Connecticut

Chair(s):

Joy A. Fritschle - University of Connecticut

Abstract(s):

• 8:00 AM Author(s):
  *Natalie Vibert - University of Connecticut
  Joy A. Fritschle - University of Connecticut
  Melinda Daniels - University of Connecticut
  

  Abstract Title: Passive Restoration of Floodplain Forest Patches along the Connecticut River.

  
  

  Restoration of floodplain forest vegetation is critical to the restoration of large river floodplain ecosystem processes. Along the Connecticut River, small patches of floodplain forest have passively regenerated after the removal of human land use impacts. This study presents results from vegetation surveys of two passively restored floodplain forest patches in Connecticut. Modern forest community composition is compared with historical forest composition reconstructed from archival data sources. A GIS is used to identify areas of potential further restoration, and recommendations are made regarding the options for active restoration management.

  Keywords: forest restoration, biogeography, floodplains

  
  
• 8:20 AM Author(s):
  *Darcy L. Boellstorff - Bridgewater State College
  

  Abstract Title: Soil Carbon and Agricultural Land Management in a Typical Semi-Arid Region of Central Spain.

  
  

  Soils in semi-arid agricultural lands are at high risk of desertification due to a combination of environmental factors that may be further compounded by social and political conditions. The same types of soil management practices that help reduce carbon losses have been shown to convert degrading soil regions into areas where soil organic matter is aggrading. This connection could stimulate the development of payments for farmers under national and regional policies aimed at reducing atmospheric CO2, while having the added benefit of soil restoration and improved agricultural sustainability in semi-arid regions. However, there is a need for better understanding factors causing spatial variation of certain types of soil carbon to determine regional estimates and farmers potential for involvement semi-arid might have in emissions-trading policy. During June 2006, 42 soil samples under different long-term land management types and landscape positions were collected in the Torrijos region of Castilla-La Mancha, Spain. Preliminary results from lab analyses show significant variation in soil carbon related factors under the different soil management and landscape position types. These results are being used in a geographic information system (GIS) to estimate medium to long-term soil carbon storage for a typical catchment in this region under different long-term land management scenarios.

  Keywords: semiarid, agriculture, desertification, soil carbon, GIS

  
  
• 8:40 AM Author(s):
  *Andrew Wilcox - U.S. Geological Survey, Geomorphology and Sediment Transport Laboratory, Golden, CO
  

  Abstract Title: Effects of a controlled flood release on native versus non-native riparian vegetation and geomorphic processes in a desert river.

  
  

  Reoperations and adaptive management of Alamo Dam on the Bill Williams River in western Arizona are emphasizing environmental flow releases to protect a cottonwood-willow riparian woodland system, including controlled flood releases in 2005 and 2006. The 2005 flood release resulted in the establishment of many riparian seedling patches co-dominated by non-native tamarisk and native willow. This work investigates the differential response of these seedlings to a controlled flood release in 2006 and how such changes are mediated by reach- and basin-scale geomorphic processes. At the site closest to dam, the flood caused scour of seedlings and their substrates from mid-channel bars and lateral shifting of bars. In a reach further downstream, tamarisk seedlings were buried as a result of aggradation, and suspended sediment concentrations were approximately twice as large as in the upstream reach. In both reaches, tamarisk suffered greater reductions in density than willow, likely as a result of the substantially greater first-year height and diameter growth of willow relative to tamarisk. Field results are being complemented by flow and sediment transport modeling using the Multidimensional Surface Water Modeling System to assess spatial patterns of velocity and shear stress in an effort to help quantify flow-sediment-vegetation relationships. This work illustrates that floods can differentially affect willow and tamarisk and that such effects are mediated by geomorphic processes on both a reach scale, where local bed gradients and geomorphic characteristics influence shear stress dynamics, and on a basin scale, where sediment supply dynamics can influence morphologic and vegetation responses.

  Keywords: tamarisk, environmental flows, adaptive management, shear stress, fluvial geomorphology

  
  
• 9:00 AM Author(s):
  *Chris Massingill - University of Oregon
  

  Abstract Title: Stream Restoration in the Sprague River Basin, Oregon: interactions of soils, water, plant communities, and land use.

  
  

  In the politically contentious Klamath Basin, stream restoration has been seen as a large part of recovery efforts for endangered fish, water quantity and quality. Exclusion of cattle from riparian corridors has been proven to be a simple and cost effective way to improve water quality through physical protection of stream banks and filtration of surface runoff from adjacent pastures. Plant communities are typically quick to respond to relief from grazing pressure, filling in bare soil areas and stabilizing otherwise transient sediments, though sometimes in unexpected ways. This project was designed to document vegetation response to fencing and to investigate riparian vegetation response to fencing as a function of soil and hydrologic conditions. Transects were located in a variety of restoration sites, ranging unfenced and grazed, to a fence just being built, to a 15-year-old fence. Transects stretched from the upper limit of the riparian zone (typically into sagebrush), to the inside limit of vegetation, often within the wetted channel. Vegetation was documented by functional group, band width on the transect, and species when possible. Soil moisture and texture were described within 40 cm of the surface. Naturally resprouting woody vegetation near the transect were identified and located. Preliminary results show considerable overlap between surface moisture and vegetation group types. Adjacent land use had a great impact on shallow ground water and riparian communities.

  Keywords: riparian, restoration, Klamath, vegetation, grazing

  
  
• 9:20 AM Author(s):
  *Joy A. Fritschle - University of Connecticut
  

  Abstract Title: Identifying representative old-growth for second-growth forest restoration.

  
  

  Old-growth forests in the American West typically represent fragments of former, more extensive forests that were subjected to nineteenth and twentieth century land-clearing activities, such as logging. These present-day forest fragments are thought to be representative of the former landscape, and thus are capable of serving as living references for restoration of logged-over lands. Yet how do we determine how well existing old-growth stands represent the former forest, especially when little of the vegetation remains after intensive logging activities such as clearcutting? Historic land surveys conducted prior to significant logging can reconstruct the former forest at the stand level, thus allowing an analysis of old-growth patches within the larger historic landscape. This study utilized original Public Land Survey field notes to assess the applicability of oldgrowth stands in Redwood National Park as reference ecosystems. A GIS and statistical analysis of the nineteenth century forest found that the vegetation communities, woody species composition, and ratios of dominant canopy species in unlogged patches were highly representative of the forests that were logged. The results of this study suggest that the national park should increase efforts to protect old-growth reference ecosystems from further human impacts, and minimize on-going degradation from edge effects by prioritizing restoration of adjoining second-growth forest.

  Keywords: ecological restoration, vegetation change, Public Land Surveys