02976nas a2200193   4500008004100000245010300041210006900144260004300213490002200256520232600278653001302604653002102617653003002638653001402668653002202682100002202704700001902726856003702745       2013                        eng d00aGrazing and drought in tallgrass prairie: the role of belowground bud banks in vegetation dynamics0 aGrazing and drought in tallgrass prairie the role of belowground  aManhattan, KSbKansas State University0 vPhD. Dissertation3 a<p>Grazing and drought are instrumental in the development and maintenance of perennial grasslands. In this research I tested the belowground bud bank contribution to tallgrass prairie resistance and resilience when perturbed by grazing and drought. First, I tested the bud bank role in vegetation response to and recovery from severe drought (Chapter 2). I compared above- and belowground responses of experimentally droughted plots to ambient controls and irrigated plots during two years of severe drought and two years of recovery. I found that although aboveground net primary productivity declined 30-60% during drought, bud bank density and demography were insensitive to drought. These results suggest that grassland resistance and resilience when perturbed by drought may be mediated by stability of belowground bud banks. Second, I investigated vegetation and soil nutrient legacies following release from long-term grazing (Chapter 3). I documented a relatively rapid shift in aboveground vegetation within four years of grazer exclusion, with productivity, stem density, and diversity becoming relatively more similar to ungrazed than grazed prairie. The density and composition of the belowground bud bank and soil seed bank shifted more slowly, remaining more similar to grazed than ungrazed prairie. Responses of soil nutrients to removal of grazers varied, and in some cases was affected by recent fire history. These results demonstrate the contribution of belowground propagules to the maintenance of a diverse plant community both during grazing and after grazers are removed. Finally, I examined short-term vegetation responses to both drought and grazing (Chapter 4). Despite extreme drought and simulated grazing that reduced productivity and increased mortality of individual stems, the dominant C4 grasses maintained a stable bud bank. Aboveground net primary productivity and bud bank density of sedges and forbs, however, were reduced by both drought and grazing. This differential response of species to extreme drought and grazing led to shifts in community composition and species diversity over one growing season. Across drought and grazing treatments, live rhizome biomass was highly correlated with bud bank density and may be a useful, more easily measured index of bud bank density.</p>10aBud bank10aGrazing; Drought10aResistance and resilience10aSeed bank10atallgrass prairie1 aVanderWeide, B.L.1 aHartnett, D.C.  uhttp://hdl.handle.net/2097/1662202271nas a2200193   4500008004100000245008900041210006900130300001300199490000700212520163300219653000901852653001301861653001401874653002201888100001501910700001901925700001301944856012001957       2004                        eng d00aBelowground bud banks and meristem limitation in tallgrass prairie plant populations0 aBelowground bud banks and meristem limitation in tallgrass prair  a416 -4210 v913 aRhizome meristem populations were sampled in tallgrass prairie to quantify the size, grass : forb composition, and temporal and spatial variability of the soil bud bank and to compare fire effects on bud bank and seed bank composition. Soil cores (10.5 cm diameter, 15 cm deep) were collected from replicate annually and infrequently burned tallgrass prairie sites, and intact rhizomes and rhizome buds were censused. Bud bank densities ranged from approximately 600 to 1800 meristems/m2 among sites and had high spatial and seasonal variability. In annually burned prairie, the total bud bank density was two-fold greater and the grass : forb meristem ratio was more than 30-fold greater than that of infrequently burned prairie. These patterns are opposite those observed in soil seed banks at this site. The rhizome population in annually burned prairie was 34% larger than the established aboveground tiller population. By contrast, the bud bank density in unburned prairie was significantly lower than aboveground stem densities, indicating possible belowground meristem limitation of stem density and net primary production on infrequently burned prairie. The patterns observed in this study suggest that the densities and dynamics of tallgrass prairie plant populations, as well as their response to disturbance (e.g., fire and grazing) and climatic variability, may be mediated principally through effects on the demography of belowground bud populations. Patterns of seed reproduction and seed bank populations have little influence on short-term aboveground population dynamics of tallgrass prairie perennials.10afire10aRhizomes10aSeed bank10atallgrass prairie1 aBenson, E.1 aHartnett, D.C.1 aMann, K.  uhttp://lter.konza.ksu.edu/content/belowground-bud-banks-and-meristem-limitation-tallgrass-prairie-plant-populations