Project Number: 5445-21310-002-02
Start Date: Feb 15, 2011
End Date: Feb 14, 2014
Three different community types will be located on the same ecological sites in north central and central South Dakota. These community types will be non-colonized by prairie dogs (OFF-TOWN) and two different communities that have been impacted by prairie dogs (ON-TOWN). The ON-TOWN communities will be further split into those that have been heavily degraded by prairie dogs (ON-TOWN HEAVY) and those that have been lightly degraded by prairie dogs (ON-TOWN LIGHT). Both ON-TOWN and OFF-TOWN communities will have cattle exclosures on them. In addition, prairie dogs will be controlled on some of the ON-TOWN sites so vegetation recovery can be evaluated with and without the presence of the two major herbivores (cattle and prairie dogs) as well as a combination of cattle and prairie dogs herbivory. Each treatment will be replicated three times. Within each replicate of each treatment, three permanent ¼ m2 quadrats will be installed. On each of these permanent quadrats, tiller densities, plant numbers, and basal areas if possible will be taken for the three most common native perennial grasses and one to two common perennial introduced grasses. A subsample of tillers for each species will be marked to develop a demographic information for each species under each treatment. Within 1 m of each permanent quadrat, vegetative and reproductive tillers for each species will be destructively harvested, placed in a cooler and transported back to the laboratory. Numbers of viable axillary buds will be determined using a double staining technique. Numbers of viable buds will be extrapolated to unit area basis using plant and tiller data to determine numbers of potential meristems per unit area. Ten point frames will be used to estimate basal, litter and bare ground cover. Biomass will be determined using the double sampling technique. Biomass on the permanent plots will not be harvested but will be estimated. Daubenmire frames will also be used to estimate foliar cover. Use of the ten-point and Daubenmire frames will provide the ability to scale up from population to community levels. Detailed soil characterizations will be conducted prior to the establishment of each treatment and five years later. Sampling sites within replicated treatments will be selected in conjunction with vegetation assessments, and identified spatially using GPS coordinates at sub-meter resolution. Variables evaluated in both baseline and 5 yr samplings will focus on near-surface (0-0.3 m) soil attributes known to respond quickly to changes in management. Measurements of soil physical (soil bulk density, aggregate stability, infiltration rate), chemical (extractable N and P, pH, particulate organic matter C and N), and biological (potentially mineralizable N, enzyme activity) will be conducted following established field and laboratory protocols. An additional sampling for total C and N within the rooting profile (1.2 m) will be conducted concurrently with the near-surface sampling to provide information on soil C and N stocks for long-term monitoring purposes. Data will be analyzed using a repeated measures model.