SER-RM PAST SCHOLARSHIPS
SER2013 World Conference
Presentation: Tuesday, October 8 in Session 2.04 Population Scale Restoration Ecology II
Title: Optimizing seed mixtures and seeding rates for restoration of surface disturbances on Colorado shortgrass steppe
Abstract: The discovery of oil and gas resources over the last decade has led to unprecedented localized and dispersed surface disturbances on shortgrass steppe ecosystems in the western US. Reclaiming and restoring these surface disturbances to native ecosystems through revegetation seedings has proven challenging. Seed mixes and rates currently used are generally similar across private and public sectors (3-10 species at rates ranging from 400-600 PLS m-2). The objective of this study was to determine an optimal seed mix diversity level and corresponding seeding rate for restoration of surface disturbances in shortgrass steppe. We examined five seed mix diversity levels, 5-50 species, and five seeding rates, 400-1600 PLS m-2 using a response surface regression experimental design. This study was implemented at twelve sites across three different locations in north central Colorado. Treatments and overall restoration success were evaluated based on resulting biomass and diversity of seeded, volunteer native, noxious, and non-native species, and the density of seeded species. Our results show greatest restoration success occurring at a seed mix diversity level of 44 species and a seeding rate of 1155 PLS m-2. These results suggest that higher seed mix diversity levels and higher seeding rates could lead to greater restoration success on surface disturbances in shortgrass steppe.
Andrea Borkenhagen, M.S. student, Colorado State University
Presentation: Wednesday, October 9 in Session 2.08 Community Scale Restoration Ecology XIII
Title: Methods for establishing rich fen mosses on reclaimed peatlands in Alberta’s oil sands region
Abstract: Northern Alberta’s oil sands deposit is the largest in the world and mining operations remove vast areas of upland forests and peatland ecosystems. Reclaiming peatlands is challenging as they require a precise hydrologic regime and take thousands of years to accumulate peat. Restoration has been conducted on degraded fens and bogs but innovative approaches are required in a post-mining landscape. Our research focuses on methods to establish moss on constructed fens and initiate carbon storage processes. We evaluated the establishment of five important rich fen moss species in response to water level and cover treatments. Moss species were introduced in equal proportions as a 1:10 ratio propagule blend to peat-mineral mixture mesocosms. Moss establishment was measured along a water table gradient of 0 to 40 cm below the peat surface to determine species distributions along hummock-hollow microsites. Three cover treatments were tested to assess the effect of microclimate moderations. Total moss cover was not significantly different between water level treatments but species distribution was. Hollow species Drepanocladus aduncus and Bryum pseudotriquetrum outcompeted hummock species Aulacomnium palustre in the wettest treatments. The opposite pattern occurred in treatments with deeper water levels. Tomentypnum nitens dominated all treatments and was unaffected by water level. Moss species percent cover and height was enhanced under wood-strand mulch and impeded under high density seedling plantings. Implications for constructed fens include applying wood-strand mulch to increase establishment and introducing a mixture of mosses that occur along natural hydrologic gradients to allow for variations in water table.
Presentation: Tuesday, October 8 in Session 1.10 Invasive Species in Restoration Ecology II
Title: Invasive plant litter is slower to decompose than native litter, and reduces native plant richness and abundance in restored and reference pools.
Abstract: Vernal pools, or ephemeral wetlands, commonly found in regions with Mediterranean climates have been rapidly converted to agriculture and land development worldwide. Vernal pools often host many rare or endemic plant species raising concern over continuing rates of habitat loss. In California, vernal pool ecosystems are also threatened by the encroachment of invasive plant species. Many invasive species are physically larger than natives, and thus could alter litter accumulation and decomposition rates within vernal pool boundaries. Thicker litter layers appear to influence the abundance and success of native plants, so we studied the dynamics of invasive plant litter and plant communities in both restored and naturally occurring pools. We investigated the effects of invasive litter by manipulating litter depth in both restored and naturally occurring pools in a long-term study site in the central valley of California. We found that overall species richness declined with increasing litter depths (P<0.0001), and that native species richness and abundance was drastically reduced, while invasive species abundance was maintained. Using litter bags filled with a prolific invasive grass (Lolium multiflorum L.) and a native grass (Pleuropogon californicus L.) revealed that P. californicus had a significantly higher decomposition rate (P<0.0001) than its invasive counterpart. Overall, our results suggest that once invasive species are established in vernal pools, invasive litter is slower to decompose and inhibits native plant abundance through higher litter depths. This effect appears to be reinforcing plant invasion, thus reducing the success of native plants and undermining restoration projects.
Mollie Herget, M.S. student, University of Wyoming
Presentation: Monday, October 7 in Session 3.11 Techniques in Restoration Ecology III
Title: An investigation of the impacts of seed origin on grassland restoration success
Abstract: While the use of local plant genotypes is ideal to restore historical site conditions, widespread biological invasion represents a significant complicating factor for ecological restoration. Some environments are so radically altered by exotic, invasive weeds that original environment conditions may no longer exist. Under these circumstances, non-local cultivars of native species may have a competitive advantage at highly disturbed sites, and the assumption that local genotypes are better adapted to site conditions than cultivars may no longer hold. In addition, different cultivated or local seed sources may represent a range of competitive ability. To test this hypothesis, a common garden study was conducted in the greenhouse and field to test the competitive interaction of native Sandberg bluegrass (Poa secunda) and invasive cheatgrass (Bromus tectorum). Multiple cultivated and local/wild varieties of P. secunda were challenged with cheatgrass and compared with controls. Final dry weights were tested to determine whether cultivar or local genotypes of the same native species have a competitive advantage in the presence of cheatgrass, and whether competitive differences are consistent among seed source categories. Results are discussed in light of biological invasion and seed sourcing for ecological restoration of invaded sites.
Presentation: Monday, October 7 in Session 3.04 Ecological Rehabilitation and Engineering II
Title: Restoration of understory plant communities in an oil and gas development region
Abstract: Declining Colorado mule deer (Odocoileus hemionus) populations have necessitated improved habitat management techniques. In particular, oil and gas development in the Piceance Basin of western Colorado has impacted critical winter range, creating a need for treatments that will increase forage. Pinyon-juniper tree removal is one such technique, however it is unclear which method of tree removal will most effectively promote forage species. Here, we quantify understory responses to pinyon-juniper canopy removal by three different methods: hydro-axing, chaining, and rollerchopping. Twenty-one 0.8-ha plots were treated during the fall of 2011 (7 replicates of each treatment). Half of each plot was seeded prior to mechanical treatment with a mix of native grasses, shrubs, and forbs. The project targets these main questions: Does mechanical thinning increase forage biomass? Which treatment is most effective? Is seeding in conjunction with thinning necessary for increasing forage biomass? Understory plant data were collected during the summer of 2012 and will be resampled again in 2013. Despite extreme drought conditions during 2012, we observed greater seeded annual plant biomass in seeded subplots compared to unseeded subplots, which suggests early seral annual species may be lacking in the seedbank. We also observed decreased grass biomass in rollerchopping and hydro-axing treatments relative to chained plots. This indicates contrasting understory impacts between the different mechanical treatments.