02862nas a2200253 4500008004100000022001400041245006900055210006400124300001600188490000800204520214500212653002402357653000802381653001302389653001102402653001602413653001302429653001702442653002402459100002302483700002302506700001902529856006002548 2019 eng d a0305-736400aThe ecology and significance of below-ground bud banks in plants0 aecology and significance of belowground bud banks in plants a1099 - 11180 v1233 a

Background
Below-ground bud banks have experienced much recent interest due to discoveries that they (1) account for the majority of seasonal population renewal in many communities, (2) are crucial to regeneration following disturbance, and (3) have important consequences for plant population dynamics and plant and ecosystem function across a number of habitats.

Scope
This review presents an overview of the role of bud banks in plant population renewal, examines bud bank life history, summarizes bud bank traits and their potential ecological implications, synthesizes the response of bud banks to disturbance, and highlights gaps to guide future research. The characteristics and life history of buds, including their natality, dormancy, protection and longevity, provide a useful framework for advancing our understanding of bud banks. The fate of buds depends on their age, size, type, location, and biotic and abiotic factors that collectively regulate bud bank dynamics. A bud bank can provide a demographic storage effect stabilizing population dynamics, and also confer resistance to disturbance and invasion. Regeneration capacity following disturbance is determined by interactions among the rates of bud natality, depletion and dormancy (meristem limitation), and the resources available to support the regeneration process. The resulting response of plants and their bud banks to disturbances such as fire, herbivory and anthropogenic sources determines the community’s regenerative capacity.

Conclusions
Vegetation responses to environmental change may be mediated through changes in bud bank dynamics and phenology. Environmental change that depletes the bud bank or prohibits its formation likely results in a loss of vegetation resilience and plant species diversity. Standardization of bud sampling, examination of bud banks in more ecosystems and their response to environmental variation and disturbance regimes, employment of stage-structured bud bank modelling and evaluation of the cost of bud bank construction and maintenance will benefit this expanding field of research.

10abelow-ground organs10aBud10aBud bank10aclonal10adisturbance10aMeristem10aPlant traits10apopulation dynamics1 aOtt, Jacqueline, P1 aKlimešová, Jitka1 aHartnett, D.C. uhttps://academic.oup.com/aob/article/123/7/1099/551169203063nas a2200193 4500008004100000245008900041210006900130260004300199490002200242520242300264653001302687653003102700653002002731653002002751653002802771100001402799700001902813856003702832 2014 eng d00aEcological implications of grass bud bank and tiller dynamics in mixed-grass prairie0 aEcological implications of grass bud bank and tiller dynamics in aManhattan, KSbKansas State University0 vPhD. Dissertation3 a

Perennial grass populations propagate vegetatively via the belowground bud bank. Climate, photosynthetic pathway, and growth form impact bud production, longevity, and dormancy; leading to alterations in bud bank and tiller dynamics. Previous research in mesic C₄-dominated tallgrass prairie revealed that a C₄ grass had greater bud longevity and differing bud bank dynamics than a C₃ species. This study examined the bud bank dynamics of rhizomatous and caespitose grasses in a more arid C₃ dominated prairie to gain insights into how bud banks differ among grass species, growth forms, and environments, and the relationship between bud bank characteristics and grass architecture and growth patterns. The bud bank and tiller dynamics of four perennial grasses in the C₃-dominated northern mixed grass prairie were examined over 15 months. The C₃ caespitose and rhizomatous grasses produced similar numbers of buds per tiller and their bud longevity was [greater than or equal to] 2 years. Tiller longevity drove the turnover within the bud bank of the dominant C₃ caespitose grasses Hesperostipa comata and Nassella viridula. Their polycyclic tillers (tillers that lived for more than one year) created multi-aged bud banks. The rhizomatous C₃ grass Pascopyrum smithii also had a multi-aged bud bank because buds were able to live longer than its annual tillers. Differences between caespitose and rhizomatous C₃ grass bud banks were driven by differences in tiller and rhizome production and spatial distribution. Responses to water availability fluctuations are likely buffered by the maintenance of polycyclic tillers in the caespitose grasses and flexible timing of annual tiller recruitment in the rhizomatous grass. The C₄ rhizomatous grass Andropogon gerardii had similar phenology to populations in its tallgrass prairie range center. Despite declines in bud production per tiller and lowered flowering probability in mixed-grass prairie, A. gerardii maintained a multi-aged bud bank and a positive population growth rate via vegetative reproduction at both the center and edge of its range. Bud bank dynamics of different growth forms and photosynthetic pathways, as they offer insight into the control of grass population dynamics and production, will enhance understanding of the mechanisms by which management practices and environmental change can alter perennial grasslands.

10aBud bank10aGrass; Mixed-grass prairie10aperennial grass10aTiller dynamics10aVegetative reproduction1 aOtt, J.P.1 aHartnett, D.C. uhttp://hdl.handle.net/2097/1727702976nas 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

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.

10aBud bank10aGrazing; Drought10aResistance and resilience10aSeed bank10atallgrass prairie1 aVanderWeide, B.L.1 aHartnett, D.C. uhttp://hdl.handle.net/2097/1662202046nas a2200181 4500008004100000245014300041210006900184300001300253490000700266520142700273653001301700653001501713653003101728653001401759100001401773700001901787856005801806 2012 eng d00aHigher-order bud production increases tillering capacity in the perennial caespitose grass Scribner's Panicum (Dichanthelium oligosanthes)0 aHigherorder bud production increases tillering capacity in the p a884 -8900 v903 a

The persistence and dynamics of perennial grass populations strongly depend on tiller recruitment from the bud bank. Because of the structural organization of grasses as populations of phytomers, bud production and tillering are constrained by morphology. An infrequent trait observed in only a few caespitose grasses is the branching of buds to produce higher-order buds prior to tiller development. We studied bud bank dynamics in Dichanthelium oligosanthes (Schult.) Gould a C3 perennial caespitose grass widely distributed in the eastern Great Plains. A hierarchy of bud development occurred in D. oligosanthes, with primary buds branching to produce secondary, tertiary, and quaternary buds. This higher-order bud production increased the overwintering propagule supply for spring recruitment by 4.5 times, and more than half of successful tiller recruits originated as higher-order buds. The temporal patterns of higher-order bud production and development suggest that growing season length may be an important factor determining the extent of higher-order bud production and subsequent year tiller natality in D. oligosanthes. Higher-order bud production likely has important consequences for the population dynamics of grasses. It may increase bud bank densities and tillering capacity, buffer population dynamics, and increase intraclonal tiller densities and resource consolidation in caespitose grasses.

10aBud bank10abunchgrass10aDichanthelium oligosanthes10atillering1 aOtt, J.P.1 aHartnett, D.C. uhttp://www.nrcresearchpress.com/doi/10.1139/b2012-04302491nas a2200229 4500008004100000245010200041210006900143300001300212490000700225520176600232653001301998653001302011653001202024653002802036653002802064100002002092700001402112700001702126700001602143700001902159856008302178 2012 eng d00aInterspecific variation in bud banks and flowering effort among semi-arid African savanna grasses0 aInterspecific variation in bud banks and flowering effort among  a127 -1330 v833 a

Population viability and productivity of grasses in southern African savannas are dependent upon both successful seed production and tiller recruitment from the belowground bud bank. Relative recruitment rates from buds versus seeds influence population dynamics, genetic diversity, and patterns of vegetation productivity. We assessed patterns in bud bank size and flowering effort in fourteen semi-arid savanna grass species in the Kalahari region of Botswana. There was high inter-specific variability and between-year variability in flowering effort (percentage of tillers flowering). Bud production (number of buds per tiller) exhibited high inter-specific variability, but was more consistent between-years than flowering effort. Relative allocation to flowering versus bud production varied with life history, with longer-lived perennial grasses showing higher bud production and lower flowering effort relative to shorter-lived grasses. Several species showed higher bud production and lower flowering effort in a wet year compared to a dry year, and grass species that are regularly grazed maintained significantly larger bud banks than non-grazed species. These differential demographic responses among co-occurring species suggest that environmental change in semi-arid savannas may alter the composition, relative abundances and diversity of grasses, and that the maintenance of a belowground bud bank is an important factor influencing their resiliency, their capacity to recover from grazing and/or drought, and their persistence and sustainability under changing environmental conditions. Meristem-limitation in species that maintain few viable buds may constrain their population viability under changing conditions in semi-arid savannas.

10aBud bank10aMeristem10aPoaceae10aReproductive allocation10aVegetative reproduction1 aDalgleish, H.J.1 aOtt, J.P.1 aSetshogo, M.1 aMuzilla, M.1 aHartnett, D.C. uhttps://www.sciencedirect.com/science/article/pii/S0254629912001275?via%3Dihub02623nas a2200241 4500008004100000245016100041210006900202300001500271490000700286520182700293653001502120653001702135653001302152653001302165653001302178653002002191653002302211653001302234653002802247100001402275700001902289856007302308 2011 eng d00aBud production and dynamics of flowering and vegetative tillers of the perennial grass Andropogon gerardii (Poaceae): the role of developmental constraints0 aBud production and dynamics of flowering and vegetative tillers  a1293 -12980 v983 a

•Premise of the Study: Perennial grasses maintain aboveground tiller populations through vegetative reproduction via belowground buds and sexual reproduction via seed. The maintenance of a bud bank has important demographic consequences for perennial grasses. A tradeoff between these reproductive modes would be expected for a plant with limited resource availability. However, the ontogeny of the tiller could affect its ability to allocate between these two modes of reproduction. •Methods: Vegetative bud production and dynamics and tiller production were examined biweekly through an annual cycle on vegetative and flowering tillers of Andropogon gerardii. •Key Results: Andropogon gerardii maintains a large reserve of dormant buds. Although vegetative and flowering tillers had similar bud phenology, flowering tillers produced larger numbers of buds of larger size, and transitioned a larger proportion of their buds to tiller, than did vegetative tillers. Therefore, a negative consequence of sexual reproduction on vegetative reproduction was not evident at the tiller level. A size threshold for floral induction likely exists that results in flowering tillers having more buds per tiller than vegetative tillers. The increased bud outgrowth of flowering tillers could be a result of their larger bud size or weaker apical dominance as compared to vegetative tillers. •Conclusions: Plant development can place significant constraints on tradeoffs between the reproductive modes in perennial grasses and could affect their plasticity in plant reproductive allocation. Differences in developmental phenology and bud production between flowering and vegetative tillers may influence grass responses to environmental changes such as altered precipitation regimes or resource availability.

10aallocation10aaxillary bud10aBud bank10aMeristem10aontogeny10aperennial grass10aTiller recruitment10atradeoff10aVegetative reproduction1 aOtt, J.P.1 aHartnett, D.C. uhttps://bsapubs.onlinelibrary.wiley.com/doi/full/10.3732/ajb.100026402661nas a2200205 4500008004100000245014300041210006900184300001300253490000800266520197800274653001302252653000902265653001202274653002302286653001302309653002802322100002002350700001902370856006602389 2009 eng d00aThe effects of fire frequency and grazing on tallgrass prairie productivity and plant composition are mediated through bud bank demography0 aeffects of fire frequency and grazing on tallgrass prairie produ a411 -4200 v2013 a

Periodic fire, grazing, and a variable climate are considered the most important drivers of tallgrass prairie ecosystems, having large impacts on the component species and on ecosystem structure and function. We used long-term experiments at Konza Prairie Biological Station to explore the underlying demographic mechanisms responsible for tallgrass prairie responses to two key ecological drivers: fire and grazing. Our data indicate that belowground bud banks (populations of meristems associated with rhizomes or other perennating organs) mediate tallgrass prairie plant response. Fire and grazing altered rates of belowground bud natality, tiller emergence from the bud bank, and both short-term (fire cycle) and long-term (>15 year) changes in bud bank density. Annual burning increased grass bud banks by 25% and decreased forb bud banks by 125% compared to burning every 4 years. Grazing increased the rate of emergence from the grass bud bank resulting in increased grass stem densities while decreasing grass bud banks compared to ungrazed prairie. By contrast, grazing increased both bud and stem density of forbs in annually burned prairie but grazing had no effect on forb bud or stem density in the 4-year burn frequency treatment. Lastly, the size of the reserve grass bud bank is an excellent predictor of long-term ANPP in tallgrass prairie and also of short-term interannual variation in ANPP associated with fire cycles, supporting our hypothesis that ANPP is strongly regulated by belowground demographic processes. Meristem limitation due to management practices such as different fire frequencies or grazing regimes may constrain tallgrass prairie responses to interannual changes in resource availability. An important consequence is that grasslands with a large bud bank may be the most responsive to future climatic change or other global change phenomena such as nutrient enrichment, and may be most resistant to exotic species invasions.

10aBud bank10afire10aGrazing10aKonza Prairie LTER10aMeristem10aVegetative reproduction1 aDalgleish, H.J.1 aHartnett, D.C. uhttps://link.springer.com/article/10.1007%2Fs11258-008-9562-303013nas a2200181 4500008004100000245006200041210006200103260004300165300001000208490002100218520245300239653001302692653001402705653001802719653002302737100002002760856005102780 2007 eng d00aBelowground bud banks as regulators of grassland dynamics0 aBelowground bud banks as regulators of grassland dynamics aManhattan, KSbKansas State University a1 -930 vPhD Dissertation3 a

In perennial grasslands, the belowground population of meristems (the bud bank) plays a fundamental role in local plant population structure and dynamics. I tested the “meristem limitation hypothesis” prediction that bud banks increase along an increasing precipitation/productivity gradient in North American grasslands. I sampled bud populations quarterly at six sites across a 1,100 km gradient in central North America. Bud banks increased with average annual precipitation, which explained 80% of variability in bud banks among sites. Seasonal changes in grass bud banks were surprisingly similar across a 2.5-fold range in precipitation and a 4-fold range of aboveground net primary productivity (ANPP). Secondly, I tested the hypothesis that tallgrass prairie plants respond to increases in a limiting resource (nitrogen) through demographic effects on the bud bank. I parameterized matrix models for individual genets, considering each genet as a population of plant parts (buds and stems). Nitrogen addition significantly impacted bud bank demography of both Sporobolus heterolepis and Koeleria macrantha. In 2005, emergence from the bud bank and growth rates (λ) of the tiller population were significantly higher in S. heterolepis genets that received nitrogen. In contrast, nitrogen addition decreased λ in K. macrantha. Both prospective and retrospective analyses indicated that bud bank dynamics are the key demographic processes driving genet responses to nutrient availability. Lastly, I tested the hypothesis that the effects of fire and grazing on plant species composition and ANPP are mediated principally through demographic effects on bud banks. I found that plants respond to fire and grazing with altered rates of belowground bud natality, bud emergence, and both short-term (fire cycle) and long-term changes in bud density. The size of the bud bank is an excellent predictor of long-term ANPP, supporting my hypothesis that ANPP is strongly regulated by belowground demographic processes. Meristem limitation due to water or nutrient availability or management practices such as fire and grazing may constrain grassland responses to inter-annual changes in resource availability. An important consequence is that grasslands with a large bud bank may be the most responsive to future climatic change or other phenomena such as nutrient enrichment, and may be most resistant to exotic species invasions.

10aBud bank10agrassland10aplant ecology10apopulation biology1 aDalgleish, H.J. uhttp://krex.k-state.edu/dspace/handle/2097/312