Hall J.E.,National Oceanic and Atmospheric Administration |
Pollock M.M.,National Oceanic and Atmospheric Administration |
Hoh S.,John Day Fossil Beds National Monument |
Volk C.,South Fork Research |
And 2 more authors.
Ecosphere | Year: 2015
Degradation of dryland riparian ecosystems has been linked to the lowering of alluvial groundwater tables and reduced floodplain connectivity. Establishing riparian plants in dryland ecosystems with high water-stress and herbivore pressure presents major challenges for restoration practitioners. By planting at sufficient depths to reach lowered water tables, deep-planting provides direct access to water and encourages root development within hydrated soils. While deep-planting is a promising alternative to traditional supplemental irrigation in dryland areas affected by lowered water tables, few studies have evaluated deep-planting where planting depths must exceed one-meter to reach water tables and where herbivore protection is required. To evaluate deep-planting as an irrigation alternative where lowered water tables present a challenge to riparian restoration, we conducted experimental plantings along an incised stream within a semiarid watershed using deep-planting without supplemental irrigation in combination with several tree shelter designs. Our results indicate deep-planting cottonwood (Populus trichocarpa) and willow (Salix spp.) pole cuttings in augered holes that penetrated water tables up to 1.9 m below the surface significantly increased the probability of survival, with water table penetration significantly increasing the odds of survival by a factor of 7. Deep-planting with access to lowered water tables in combination with 0.9-m vented plastic tree shelters significantly increased the probability of survival, with over 50% higher survival after three years compared to unprotected and 1.-m circular fence caged plants that were also deepplanted with access to water. However, taller fence cages significantly reduced the probability of terminal bud loss from browsers with over 25% lower browse rates after three years. Therefore, we conducted additional experimental plantings to evaluate two taller plastic tree shelter designs to maximize survival while minimizing browsing. The results of our study indicate that deep-planting pole cuttings of cottonwood and willow with access to lowered water tables in combination with taller 1.8-m vented plastic tree shelters provided statistically similar survival as compared to the shorter 0.9-m vented plastic tree shelters after two years while significantly reducing browsing by approximately 75% two years after planting. © 2015 Hall et al. Source
Strand E.K.,University of Idaho |
Bunting S.C.,University of Idaho |
Starcevich L.A.,Western EcoSystems Technology Inc. |
Nahorniak M.T.,South Fork Research |
And 2 more authors.
Environmental Monitoring and Assessment | Year: 2015
Aspen woodland is an important ecosystem in the western United States. Aspen is currently declining in western mountains; stressors include conifer expansion due to fire suppression, drought, disease, heavy wildlife and livestock use, and human development. Forecasting of tree species distributions under future climate scenarios predicts severe losses of western aspen within the next 50 years. As a result, aspen has been selected as one of 14 vital signs for long-term monitoring by the National Park Service Upper Columbia Basin Network. This article describes the development of a monitoring protocol for aspen including inventory mapping, selection of sampling locations, statistical considerations, a method for accounting for spatial dependence, field sampling strategies, and data management. We emphasize the importance of collecting pilot data for use in statistical power analysis and semi-variogram analysis prior to protocol implementation. Given the spatial and temporal variability within aspen stem size classes, we recommend implementing permanent plots that are distributed spatially within and among stands. Because of our careful statistical design, we were able to detect change between sampling periods with desired confidence and power. Engaging a protocol development and implementation team with necessary and complementary knowledge and skills is critical for success. Besides the project leader, we engaged field sampling personnel, GIS specialists, statisticians, and a data management specialist. We underline the importance of frequent communication with park personnel and network coordinators. © 2015, Springer International Publishing Switzerland. Source
Pollock M.M.,U.S. National Center for Atmospheric Research |
Beechie T.J.,U.S. National Center for Atmospheric Research |
Wheaton J.M.,Utah State University |
Jordan C.E.,U.S. National Center for Atmospheric Research |
And 3 more authors.
BioScience | Year: 2014
Biogenic features such as beaver dams, large wood, and live vegetation are essential to the maintenance of complex stream ecosystems, but these features are largely absent from models of how streams change over time. Many streams have incised because of changing climate or land-use practices. Because incised streams provide limited benefits to biota, they are a common focus of restoration efforts. Contemporary models of long-term change in streams are focused primarily on physical characteristics, and most restoration efforts are also focused on manipulating physical rather than ecological processes. We present an alternative view, that stream restoration is an ecosystem process, and suggest that the recovery of incised streams is largely dependent on the interaction of biogenic structures with physical fluvial processes. In particular, we propose that live vegetation and beaver dams or beaver dam analogues can substantially accelerate the recovery of incised streams and can help create and maintain complex fluvial ecosystems. © 2014 The Author(s). Source