https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1537&context=usgsstaffpub

Monitoring gradual ecosystem change using Landsat time series analyses: Case studies in selected forest and rangeland ecosystems

https://d2k78bk4kdhbpr.cloudfront.net/media/content/files/King_et_al_2015_VcrHRIB.pdf

Estimation of potential evapotranspiration from extraterrestrial radiation, air temperature and humidity to assess future climate change effects on the vegetation of the Northern Great Plains, USA

The United States Northern Great Plains (NGP) has a high potential for landscape-scale conservation, but this grassland landscape is threatened by encroachment of woody species. We surveyed NGP land managers to identify patterns in, and illustrate a broad range of, individual managers' perceptions on (1) the threat of woody encroachment to grasslands they manage, and (2) what management practices they use that may influence woody encroachment in this region. In the 34 surveys returned, which came from predominantly public lands in the study area, 79% of responses reported moderate or substantial woody encroachment. Eastern redcedar (Juniperus virginiana) and Rocky Mountain juniper (Juniperus scopulorum) were the most problematic encroachers. Thirty-one survey respondents said that prescribed fire was used on the lands they manage, and 64% of these responses reported that controlling woody encroachment was a fire management objective. However, only 18% of survey respondents using prescribed fire ...

/pdf/woody-encroachment-in-northern-great-plains-grasslands-3fnxw4hqp7.pdf

Woody encroachment in Northern Great Plains grasslands: perceptions, actions, and needs.

Woody encroachment of grasslands is a common phenomenon worldwide, but the consequences of this encroachment for ecosystem carbon storage, particularly belowground are not clear. We quantified total ecosystem carbon in the 3 major natural upland vegetation communities (grassland, shrubland, and forest) at the northern edge of the North American Great Plains. Total ecosystem carbon storage was significantly greater in forest (125.3 mg C·ha-1) than in shrubland (92.4 mg C·ha-1) or grassland (80.7 mg C·ha-1), and this difference was due mainly to greater aboveground biomass, coarse root biomass, and the presence of a humus layer in the forest. Fine and total root biomass were also greater in forest than shrubland or grassland. In contrast, soil carbon was significantly greater in shrubland (80.6 mg C·ha-1) and grassland (75.4 mg C·ha-1) than in forest (48.6 mg C·ha-1). We also investigated whether aboveground variables could be used to predict belowground carbon pools. Soil carbon increased signifi...

Ecosystem carbon changes with woody encroachment of grassland in the northern Great Plains

Tree and forest encroachment into fescue grasslands on the Cypress Hills plateau, southeast Alberta, Canada.

We evaluated the status of remnant prairie patches in the Loess Hills of southeastern South Dakota using three parallel approaches. Aerial photograph analysis, vegetation surveys and stable carbon isotope analysis of soil organic matter all yielded evidence of woody plant encroachment. Time series analysis of aerial photos indicated that forest cover expanded by 37.5% between 1941 and 2000. Vegetation surveys revealed several distinct community types ranging from forested ravines supporting basswood, American elm and black walnut trees to upland prairie remnants and oak savannas that now include encroaching eastern red cedar trees, and/or a dense understory of prickly ash, ironwood and other woodland species moving up from the ravines. Finally, carbon isotope values (δ13C) in soil cores decreased as much as 5–7‰ towards the soil surface consistent with increased prevalence of C3 forest species over C4 prairie species in recent years. One consequence of forest encroachment appears to be an increas...

Forest Expansion and Soil Carbon Changes in the Loess Hills of Eastern South Dakota

Thirty six male ring-necked pheasants (Phasianus colchinus) were harvested in South Dakota and Wisconsin from a variety of habitats supporting differing plant communities. Feeding habits of the birds were evaluated by visually identifying gross crop contents and stable isotope ratios of carbon ( 13 C/ 12 C) from different regions of tail feathers. Carbon isotope ratios are useful tracers in food webs since the isotopic signals of ingested food become incorporated and expressed in the tissues of consumers. We found that pheasant crop contents are significantly correlated with the δ 13 C values of the calamus (Fall growth) of the feather. Their was no significant correlation between the δ 13 C of the rachis (Summer growth) and crop contents. The findings demonstrate that crop content analysis is accurate only over short periods of time, whereas, stable isotope analysis of feathers can show diet changes over several months. Our study also found that pheasants shift their diet toward a higher C4 plant consumption in the Fall as compared to Summer. The significance of pheasant diet shifting appears to depend on land-use and C4 plant source availability. When δ 13 C values are compared to C4 crop landuse, a significant logarithmic relationship exists. The pheasant diet appears to be saturated in C4 at approximately 40% C4 crop land-use. The techniques used may have applications for non-destructive diet studies in pheasants and help provide information for pheasant habitat management.

/pdf/foraging-ecology-of-ring-necked-pheasants-recorded-in-the-2bx5yzu6mm.pdf

Michael E. Chapman

Papers

Forest Expansion and Soil Carbon Changes in the Loess Hills of Eastern South Dakota

Foraging ecology of ring-necked pheasants recorded in the stable isotope signature of feathers