@article {KNZ001936, title = {Long- and short-term responses of Asclepias species differ in respect to fire, grazing, and nutrient addition}, journal = {American Journal of Botany}, volume = {105}, year = {2018}, pages = {2008-2017}, abstract = {

PREMISE OF THE STUDY: The tallgrass prairie ecosystem has experienced a dramatic reduction over the past 150 yr. This reduction has impacted the abundance of native grassland species, including milkweeds (Asclepias).


METHODS: We used two long-term (27 yr) data sets to examine how fire, grazing, and nutrient addition shape milkweed abundance in tallgrass prairie. We compared these results to those of a greenhouse experiment that varied nutrient levels in the absence of competition, herbivory, and mutualistic relationships.


KEY RESULTS: Asclepias species exhibited broad patterns in response to burning regimes that did not include grazing, but experienced more species-specific patterns in other combinations. Asclepias syriaca was the only species to increase in abundance in plots that included burning and nutrient addition. In the greenhouse we found that nitrogen significantly increased biomass, while no effect of phosphorus was detected.


CONCLUSIONS: These results indicate that A. syriaca will do best in settings with high nutrient loads, low competition, and no grazers. These characteristics define a small portion of the tallgrass prairie but exemplify modern agricultural settings, which have replaced prairies. However, other milkweeds examined did not share this pattern, which indicates that milkweed species will respond differently when exposed to agricultural settings, with some less able to cope with land conversion to pasture or row-crop agriculture.

}, keywords = {LTER-KNZ}, doi = {10.1002/ajb2.2018.105.issue-1210.1002/ajb2.1197}, url = {https://bsapubs.onlinelibrary.wiley.com/doi/full/10.1002/ajb2.1197}, author = {Ricono, A. and Dixon, R. and Eaton, I. and Brightbill, C.M. and Yaziji, Y. and Puzey, J.R. and Dalgleish, H.J.} } @article {KNZ001550, title = {Interspecific variation in bud banks and flowering effort among semi-arid African savanna grasses}, journal = {South African Journal of Botany}, volume = {83}, year = {2012}, pages = {127 -133}, abstract = {

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.

}, keywords = {LTER-KNZ, Bud bank, Meristem, Poaceae, Reproductive allocation, Vegetative reproduction}, doi = {10.1016/j.sajb.2012.08.010}, url = {https://www.sciencedirect.com/science/article/pii/S0254629912001275?via\%3Dihub}, author = {Dalgleish, H.J. and Ott, J.P. and Setshogo, M. and Muzilla, M. and D.C. Hartnett} } @article {KNZ001317, title = {The effects of fire frequency and grazing on tallgrass prairie productivity and plant composition are mediated through bud bank demography}, journal = {Plant Ecology}, volume = {201}, year = {2009}, pages = {411 -420}, abstract = {

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.

}, keywords = {LTER-KNZ, Bud bank, fire, Grazing, Konza Prairie LTER, Meristem, Vegetative reproduction}, doi = {10.1007/s11258-008-9562-3}, url = {https://link.springer.com/article/10.1007\%2Fs11258-008-9562-3}, author = {Dalgleish, H.J. and D.C. Hartnett} } @article {KNZ001207, title = {Comparing ecosystem goods and services provided by restored and native lands}, journal = {BioScience}, volume = {58}, year = {2008}, pages = {837 -845}, abstract = {

We determined the relative benefits for eight categories of ecosystem goods and services associated with native and restored lands across the conterminous United States. Less than 10\% of most native US ecosystems remain, and the proportion that is restored varies widely by biome. Restored lands offer 31\% to 93\% of native land benefits within a decade after restoration, with restored wetlands providing the most economic value and deserts providing the least. Restored ecosystems that recover rapidly and produce valuable commodities return a higher proportion of total value. The relative values of the benefits provided by restoration vary both by biome and by the ecosystem goods and services of interest. Our analysis confirms that conservation should be the first priority, but that restoration programs across broad geographic regions can have substantial value. \“No net loss\” policies should recognize that restored lands are not necessarily equivalent to native areas with regard to estimated ecosystem benefits.

}, keywords = {LTER-KNZ, conservation, ecosystem goods, ecosystem services, ecosystem valuation, restoration}, doi = {10.1641/B580909}, url = {https://academic.oup.com/bioscience/article/58/9/837/250939}, author = {W. K. Dodds and Wilson, K.C. and Rehmeier, R.L. and Knight, G.L. and Wiggam, S. and Falke, J.A. and Dalgleish, H.J. and Bertrand, K.N.} } @booklet {KNZ001222, title = {The effects of bison grazing on plant diversity in a tallgrass prairie (Konza Prairie LTER). Teaching Issues and Experiments in Ecology}, journal = {Teaching Issues and Experiments in Ecology}, year = {2008}, keywords = {LTER-KNZ}, url = {http://tiee.ecoed.net/vol/v5/practice/dalgleish/abstract.html}, author = {Dalgleish, H.J. and Woods, T.M.} } @article {KNZ001212, title = {Responses of two bunchgrasses to nitrogen addition in tallgrass prairie: the role of bud bank demography}, journal = {American Journal of Botany}, volume = {95}, year = {2008}, pages = {672 -680}, abstract = {Growth 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.}, keywords = {LTER-KNZ, kansas, Koeleria macrantha, Konza Prairie Long-Term Ecological Research Site, Meristem, Poaceae, Sporobolus heterolepis}, doi = {10.3732/ajb.2007277}, author = {Dalgleish, H.J. and Kula, A.R. and D.C. Hartnett and Sandercock, B.K.} } @phdthesis {KNZ001104, title = {Belowground bud banks as regulators of grassland dynamics}, volume = {PhD Dissertation}, year = {2007}, pages = {1 -93}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, abstract = {

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.

}, keywords = {LTER-KNZ, Bud bank, grassland, plant ecology, population biology}, url = {http://krex.k-state.edu/dspace/handle/2097/312}, author = {Dalgleish, H.J.} } @article {KNZ001043, title = {Belowground bud banks increase along a precipitation gradient of the North American Great Plains: a test of the meristem limitation hypothesis}, journal = {New Phytologist}, volume = {171}, year = {2006}, pages = {81 -89}, abstract = {{\textbullet} In perennial grasslands, the below-ground population of meristems (bud bank) plays a fundamental role in plant population dynamics. Here, we tested the {\textquoteleft}meristem limitation hypothesis{\textquoteright} prediction {\textendash} that bud banks increase along an increasing precipitation/productivity gradient in North American grasslands {\textendash} and assessed the seasonal dynamics of bud banks. {\textbullet} We sampled bud and stem populations quarterly at six sites across a 1100 km gradient in central North America. {\textbullet} Bud banks increased with average annual precipitation, which explained 80\% of the variability between the sites. In addition, seasonal changes in grass bud banks were surprisingly similar across a 2.5-fold range in precipitation and a 4-fold range of productivity: densities peaked in March, decreased in June and increased slightly in September. {\textbullet} Increasing meristem limitation may constrain vegetation responses to inter-annual changes in resources. An important consequence of this is that biomes with large bud banks may be the most responsive to environmental change. If meristem limitation represents an important constraint on productivity responses to environmental variability, then bud banks must be considered in developing predictive models for grassland responses to environmental change.}, keywords = {LTER-KNZ}, doi = {10.1111/j.1469-8137.2006.01739.x}, author = {Dalgleish, H.J. and D.C. Hartnett} } @article {KNZ001044, title = {Bud banks of perennial savanna grasses in Botswana}, journal = {African Journal of Ecology}, volume = {44}, year = {2006}, pages = {256 -263}, abstract = {Three semi-arid savanna grasses in Botswana (Stipagrostis uniplumis, Eragrostis lehmanniana, and Aristida stipitata) were sampled to quantify their belowground bud banks during the dormant season and to estimate their relative allocation to vegetative and sexual reproduction. Bud banks of these African perennial caespitose grasses were also compared with four perennial caespitose grasses of semi-arid North American grasslands. The three African grasses each maintained approximately two buds per tiller and showed a high percentage (88{\textendash}99\%) of tillers producing seed. Only E. lehmanniana produced new aerial tillers from axillary buds at elevated nodes on the stem as well as from the belowground bud bank. Compared with species of North American grasslands, these African grasses produced fewer belowground buds but showed a much higher percentage of tillers producing seed. These patterns indicate relatively greater belowground meristem limitation, lower allocation to vegetative reproduction (tillering) and higher allocation to seed reproduction in these African grasses, although studies of more species are needed to assess the generality of this pattern. The management of savannas in ways that favour the maintenance of a reserve population of belowground buds may increase the ability of grasses to respond to pulses of resource availability, increase their compensatory growth capacity following grazing or drought, and decrease the invasibility of these plant communities by exotic species, whereas maintaining allocation to sexual reproduction may be important for conserving genetic variation and enhancing their capacity to adapt to environmental change.}, keywords = {LTER-KNZ, clonal plants, meristems, Plant demography, reproductive strategy, Vegetative reproduction}, doi = {10.1111/j.1365-2028.2006.00646.x}, author = {D.C. Hartnett and Setshogo, M.P. and Dalgleish, H.J.} }