02316nas a2200229   4500008004100000245010900041210006900150300001300219490000700232520151000239653001101749653002301760653005301783653001301836653001201849653002701861100002001888700001501908700001901923700002101942856012301963       2008                        eng d00aResponses of two bunchgrasses to nitrogen addition in tallgrass prairie: the role of bud bank demography0 aResponses of two bunchgrasses to nitrogen addition in tallgrass   a672 -6800 v953 aGrowth of tallgrass prairie plants, many of which maintain substantial bud banks, can be limited by nitrogen (N), water, and/or light. We hypothesized that tallgrass prairie plants respond to increases in N through demographic effects on the bud bank. We tested the effects of a pulse of N on (1) bud bank demography, (2) plant reproductive allocation, and (3) ramet size. We parameterized matrix models, considering each genet as a population of plant parts. Nitrogen addition significantly impacted bud bank demography in two subdominant species of bunchgrass: Sporobolus heterolepis (a C4 grass) and Koeleria macrantha (a C3 grass), but had no effect on the size of individual ramets. Emergence from the bud bank and ramet population growth rates (λ) were significantly higher in S. heterolepis genets that received supplemental N. Nitrogen addition also affected the bud demography of K. macrantha, but N addition decreased rather than increased λ. Prospective and retrospective demographic analyses indicated that bud bank dynamics were the most important demographic processes driving plant responses to nutrient availability. Thus, the variation in productivity in these tallgrass prairie species is driven principally by the demography of the bud bank rather than by the physiology and growth of aboveground tillers. Improved understanding of bud bank dynamics may lead to improved predictive models of grassland responses to environmental changes such as altered N deposition and precipitation.10akansas10aKoeleria macrantha10aKonza Prairie Long-Term Ecological Research Site10aMeristem10aPoaceae10aSporobolus heterolepis1 aDalgleish, H.J.1 aKula, A.R.1 aHartnett, D.C.1 aSandercock, B.K.  uhttp://knz.lternet.edu/content/responses-two-bunchgrasses-nitrogen-addition-tallgrass-prairie-role-bud-bank-demography