@article {KNZ00766,
	title = {Below-ground carbon and nitrogen accumulation in perennial grasses: A comparison of caespitose and rhizomatous growth forms},
	journal = {Plant and Soil},
	volume = {237},
	year = {2001},
	pages = {117 -127},
	abstract = {An experiment was conducted to compare below-ground soil organic carbon and total nitrogen accumulation between caespitose and rhizomatous perennial grasses in long-term (<25 yrs) grazed and ungrazed sites in semi-arid and mesic communities in the North American Great Plains. Development of greater nutrient pools beneath than between clones occurred at minimal clone basal areas (<60 cm2) for both caespitose species. Caespitose grasses accumulated substantially greater pools of carbon (20{\textendash}200 fold) and nitrogen (50{\textendash}500 fold) in soils to a depth of 10 cm beneath clones than rhizomatous grasses accumulated in rhizomes in both communities. Carbon and nitrogen pools in soils beneath caespitose clones exceeded combined (soil + rhizome) pools for rhizomatous grasses for a majority of the clone basal areas (>90 cm2) in the mesic community. In contrast, both pool sizes were smaller beneath the caespitose grass at all clone basal areas than the combined pools for the rhizomatous grass in the semi-arid community. The occurrence of larger soil nutrient pools beneath the rhizomatous species in the semi-arid community was largely a consequence of niche separation for microsites characterized by soils with higher nutrient concentrations, rather than plant-induced increases in nutrient concentrations. Although nutrient islands do not occur beneath rhizomatous grasses, their distribution in the semi-arid community was restricted to microsites characterized by soils with higher SOC and N concentrations. A greater efficiency of nutrient accumulation per unit rhizome mass and the maintenance of rhizome nutrient pools of similar magnitude to those of the rhizomatous grass in the mesic community may also contribute to the distribution of rhizomatous grasses in semi-arid communities. The existence of nutrient islands beneath a wide range of clone sizes in both mesic and semi-arid communities provides circumstantial evidence to suggest that nutrient islands beneath caespitose grasses may contribute to clone fitness in this growth form.},
	keywords = {LTER-KNZ, Grazing, islands of fertility, nutrient accumulation, nutrient islands, shortgrass prairie, tallgrass prairie},
	doi = {10.1023/A:1013316829961},
	author = {Derner, J.D. and Briske, D.D.}
}
@proceedings {KNZ00684,
	title = {Do caespitose and rhizomatous grass growth forms constitute unique functional groups?},
	journal = {People and Rangelands: Building the Future},
	year = {1999},
	pages = {927 -928},
	address = {Townsville, Queensland, Australia},
	abstract = {Studies of a semiarid shortgrass plant community (Central Plains Experimental Range, Colorado, USA) and a mesic tallgrass community (Konza Prairie Research Natural Area, Kansas, USA) are described. Soil C and N pools were measured from soil cores taken below rhizomatous and caespitose grass species from both grazed and ungrazed sites. Physiological plasticity was determined for the roots of both grass types by exposure to ammonium sulfate solution and rhizome and root morphological plasticity was determined on the long-term grazed sites. Caespitose grasses [Schizachyrium scoparium and Bouteloua gracilis] accumulated larger pools of nutrients in soils directly beneath plants than rhizomatous grasses [Andropogon gerardii and Pascopyrum smithii [Elymus smithii]] did in rhizomes. Caespitose and rhizomatous grasses had inconsistent modifications of nutrient pools on grazed compared with ungrazed sites, which indicated the occurrence of either species- or system-specific responses. Neither grass type expressed morphological or physiological root plasticity in the mesic community but both grass types expressed morphological root plasticity and the rhizomatous grass displayed significant physiological root plasticity in the semiarid plant community},
	keywords = {LTER-KNZ},
	author = {Derner, J.D. and Briske, D.D. and Eldridge, D. and Freudenberger, D.},
	editor = {Eldridge, D. and Freudenberger, D.}
}
@article {KNZ00683,
	title = {Does a tradeoff exist between morphological and physiological root plasticity? A comparison of grass growth forms},
	journal = {Acta Oecologica},
	volume = {20},
	year = {1999},
	pages = {519 -526},
	abstract = {A series of experiments were conducted to evaluate the potential tradeoff between morphological and physiological root plasticity in caespitose and rhizomatous grass growth forms in semi-arid and mesic communities. Morphological and physiological root plasticity were evaluated with in-growth cores and excised root assays, respectively. The rhizomatous grass in the semi-arid community was the only species to display significant physiological root plasticity, but all species possessed the capacity to proportionally increase 15N uptake with increasing concentrations of (15NH4)2SO4 solution. Neither the caespitose nor the rhizomatous grass displayed morphological root plasticity in response to nitrogen addition in the mesic community. In contrast, significant morphological root plasticity occurred in species of both growth forms in the semi-arid community. These data suggest that the compact architecture and the ability to accumulate nutrients in soils directly beneath caespitose grasses did not increase selection pressure for physiological root plasticity at the expense of morphological root plasticity and that the coarse grained foraging strategy and low density of large diameter roots did not increase morphological root plasticity at the expense of physiological root plasticity in rhizomatous grasses. These preliminary data suggest that 1) a high maximum uptake rate for nitrogen in these perennial grasses may minimize the expression of physiological root plasticity, 2) morphological and physiological root plasticity may represent complimentary, rather than alternative, foraging strategies, and 3) the expression of root plasticity may be strongly influenced by abiotic variables within specific habitats.},
	keywords = {LTER-KNZ, clonal plants, plant foraging, plant-soil relations, Resource heterogeneity},
	doi = {10.1016/S1146-609X(00)86619-9},
	author = {Derner, J.D. and Briske, D.D.}
}
@phdthesis {KNZ00951,
	title = {Clonal biology of the caespitose grass Schizachyrium scoparium: mechanisms of intraclonal regulation and ecological success},
	volume = {PhD Dissertation},
	year = {1996},
	pages = {1 -108},
	school = {Texas A\&M University},
	type = {Ph.D. Thesis},
	address = {College Station, TX},
	keywords = {LTER-KNZ},
	author = {Derner, J.D.}
}
