@article {KNZ001910, title = {Restoring grassland in the context of climate change}, journal = {Grasslands and Climate Change}, year = {2019}, pages = {310 -322}, keywords = {LTER-KNZ}, doi = {10.1017/9781108163941.020}, url = {https://doi.org/10.1017/9781108163941.020}, author = {S.G. Baer and D.J. Gibson and Johnson, L.C.}, editor = {D.J. Gibson and Newman, J.A.} } @article {KNZ001610, title = {Convergent and contingent community responses to grass source and dominance during prairie restoration across a longitudinal gradient}, journal = {Environmental Management}, volume = {53}, year = {2014}, pages = {252 -265}, abstract = {

Restoring prairie on formerly cultivated land begins by selecting propagule seed sources and the diversity of species to reintroduce. This study examined the effects of dominant grass propagule source (cultivar vs. non-cultivar) and sown propagule diversity (grass:forb sowing ratio) on plant community structure. Two field experiments were established in Kansas and Illinois consisting of identical split plot designs. Dominant grass source was assigned as the whole-plot factor, and sown dominance of grasses (five levels of seeded grass dominance) as the subplot factor. Species density, cover, and diversity were quantified for 5 years. The effect of dominant grass source on the cover of focal grasses, sown species, and volunteer species was contingent upon location, with variation between dominant grass sources observed exclusively in Kansas. Species density and diversity showed regionally convergent patterns in response to dominant grass source. Contrary to our hypotheses, total species density and diversity were not lower in the presence of grass cultivars, the grass source we had predicted would be more competitive. Sown grass dominance effects on the cover of the focal grass species were contingent upon location resulting from establishment corresponding better to the assigned treatments in Illinois. All other cover groups showed regionally convergent patterns, with lower cover of volunteers and higher cover of sown forbs, diversity, and species density in the lowest sown grass dominance treatment in both sites. Thus, decisions regarding the diversity of propagules to reintroduce had more consequence for plant community structure than cultivar or non-cultivar source of dominant grasses.

}, keywords = {LTER-KNZ, Ecotype, grassland, restoration, Seed source}, doi = {10.1007/s00267-013-0209-3}, url = {https://link.springer.com/article/10.1007\%2Fs00267-013-0209-3}, author = {Klopf, R.P. and S.G. Baer and D.J. Gibson} } @article {KNZ001564, title = {Fitness among population sources of a dominant species (Andropogon gerardii Vitman) used in prairie restoration}, journal = {Torrey Botanical Society}, volume = {140}, year = {2014}, pages = {269 -279}, abstract = {

Planting native grasses can provide a source of seed for prairie restorations, but requires knowledge of how the plants that establish will perform. This study sought to determine variation in fitness of population sources of Andropogon gerardii, a dominant grassland species, when grown in a mesic common garden. Using multiple population sources, we tested the hypothesis that plants from populations within the local region would exhibit a \‘home-site advantage\’ as measured by higher fitness compared to plants from populations collected from drier regions of the tallgrass prairie ecosystem (up to 986 km west of the common garden). Plants collected from four pristine, never restored population sources from each of three regions (central Kansas, eastern Kansas, and southern Illinois) were raised in the greenhouse from seeds and planted in a common garden in Illinois. To estimate fitness, we used commonly measured traits related to seed production, including flowering tiller number and number of flowering raceme branches, seed number, viability, and percentage germination. There was no evidence of a \‘home-site advantage\’ for populations originating from southern Illinois. Rather, there was high within-region variability in fecundity. Plants from southern Illinois had the largest number of raceme branches per plant. Plants from eastern Kansas had the highest number of vegetative tillers per plant. Plants from central Kansas produced the most germinable seeds. Under the current climate, plants from any one of the three regions may be suitable to propagate seeds for restoration, but other traits may vary among populations to affect height, cover, and productivity.

}, keywords = {LTER-KNZ, Andropogon gerardii, fitness, grassland, reproductive effort, restoration}, doi = {10.3159/TORREY-D-12-00063.1}, url = {https://doi.org/10.3159/TORREY-D-12-00063.1}, author = {D.J. Gibson and Sendor, G. and Donatelli, J. and S.G. Baer and Johnson, L.} } @article {KNZ001611, title = {No effect of seed source on multiple aspects of ecosystem functioning during ecological restoration: cultivars compared to local ecotypes of dominant grasses}, journal = {Evolutionary Applications}, volume = {7}, year = {2014}, pages = {323 -335}, abstract = {

Genetic principles underlie recommendations to use local seed, but a paucity of information exists on the genetic distinction and ecological consequences of using different seed sources in restorations. We established a field experiment to test whether cultivars and local ecotypes of dominant prairie grasses were genetically distinct and differentially influenced ecosystem functioning. Whole plots were assigned to cultivar and local ecotype grass sources. Three subplots within each whole plot were seeded to unique pools of subordinate species. The cultivar of the increasingly dominant grass, Sorghastrum nutans, was genetically different than the local ecotype, but genetic diversity was similar between the two sources. There were no differences in aboveground net primary production, soil carbon accrual, and net nitrogen mineralization rate in soil between the grass sources. Comparable productivity of the grass sources among the species pools for four years shows functional equivalence in terms of biomass production. Subordinate species comprised over half the aboveground productivity, which may have diluted the potential for documented trait differences between the grass sources to influence ecosystem processes. Regionally developed cultivars may be a suitable alternative to local ecotypes for restoration in fragmented landscapes with limited gene flow between natural and restored prairie and negligible recruitment by seed.

}, keywords = {LTER-KNZ, genetic diversity, genetic structure, grassland, prairie, propagule, soil}, doi = {10.1111/eva.12124}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/eva.12124}, author = {S.G. Baer and D.J. Gibson and Benscoter, A.M. and Reed, L.K. and Campbell, R.E. and Klopf, R.P. and Willand, J.E. and Wodika, B.R.} } @article {KNZ001565, title = {Limited effects of dominant species population source on community composition during community assembly}, journal = {Journal of Vegetation Science}, volume = {24}, year = {2013}, pages = {429 -440}, abstract = {

Question To what extent do dominant species population sources and subordinate species pools affect diversity and composition of an assembling grassland community? Location Illinois, USA. Methods Percentage cover of all species were recorded annually in 36 1-m2 quadrats assigned to a factorial combination of dominant species population source (functionally distinct cultivar or non-cultivar seed source) and designed species pool (three levels varying in species identity, but with equal functional group representation and richness) during the first 4 yr of community assembly in an experimental grassland restoration. Results Univariate and multivariate analyses showed that individual species abundance, life form and community composition differed significantly among designed species pools, but were not strongly affected by population source of the dominant species (cultivar or non-cultivar). There were fewer C4 species in cultivar plots but only in one of three designed species pools during one of 4 yr of community assembly. The number of legume and forb species was higher in cultivar plots, but also only in one of the 4 yr of study. Other changes in species richness and abundance were solely related to successional change. Conclusions Non-dominant species introduced to restore plant communities strongly affects plant community composition, and composition can show fidelity to designed species pools. Only marginal or temporary effects of dominant species seed source were observed in the assembling plant community. Thus, we found no strong evidence that the source of dominant species, in this case cultivars compared to local ecotypes, has consequences for community assembly in the early stages of restoration (1\–4 yr). The absence of a strong dominant species source effect may be exacerbated by the assembly of diverse plant communities, resulting in a stronger effect of subordinate species seed mixture in restoration.

}, keywords = {LTER-KNZ, Community assembly, dominant species, Extended phenotype, grassland, restoration, Seed pool, tallgrass prairie}, doi = {10.1111/j.1654-1103.2012.01475.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1654-1103.2012.01475.x}, author = {D.J. Gibson and S.G. Baer and Klopf, R.P. and Reed, L.K. and Wodika, B.R. and Willand, J.E.} } @inbook {KNZ001655, title = {Restoration Ecology}, booktitle = {Oxford Bibliographies in Ecology}, year = {2013}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ}, url = {http://www.oxfordbibliographies.com}, author = {S.G. Baer}, editor = {D.J. Gibson} } @article {KNZ001562, title = {Temporal dynamics of plant community regeneration sources during tallgrass prairie restoration}, journal = {Plant Ecology}, volume = {214}, year = {2013}, pages = {1169 -1180}, abstract = {

Ecological restoration aims to augment and steer the composition and contribution of propagules for community regeneration in degraded environments. We quantified patterns in the abundance, richness, and diversity of seed and bud banks across an 11-year chronosequence of restored prairies and in prairie remnants to elucidate the degree to which the germinable seed bank, emerged seedlings, belowground buds, and emerged ramets were related to community regeneration. There were no directional patterns in the abundance, richness, or diversity of the germinable seed bank across the chronosequence. Emerged seedling abundance of sown species decreased during restoration. Richness and diversity of all emerged seedlings and non-sown emerged seedling species decreased across the chronosequence. Conversely, abundance and richness of belowground buds increased with restoration age and belowground bud diversity of sown species increased across the chronosequence. Numbers of emerged ramets also increased across the chronosequence and was driven primarily by the number of graminoid ramets. There were no temporal changes in abundance and richness of sown and non-sown emerged ramets, but diversity of sown emerged ramets increased across the chronosequence. This study demonstrates that after initial seeding, plant community structure in restored prairies increasingly reflects the composition of the bud bank.

}, keywords = {LTER-KNZ, chronosequence, Community assembly, diversity, Propagules, Species richness}, doi = {10.1007/s11258-013-0241-7}, url = {https://link.springer.com/article/10.1007\%2Fs11258-013-0241-7}, author = {Willand, J.E. and S.G. Baer and D.J. Gibson and Klopf, R.P.} } @article {KNZ001436, title = {Effects of foundation species genotypic diversity on subordinate species richness in an assembling community}, journal = {Oikos}, volume = {121}, year = {2012}, pages = {496 -507}, abstract = {

Foundation (dominant or matrix) species play a key role in structuring plant communities, influencing processes from population to ecosystem scales. However, the effects of genotypic diversity of foundation species on these processes have not been thoroughly assessed in the context of assembling plant communities. We modified the classical filter model of community assembly to include genotypic diversity as part of the biotic filter. We hypothesized that the proportion of fit genotypes (i.e. competitively superior and dominant) affects niche space availability for subordinate species to establish with consequence for species diversity. To test this hypothesis, we used an individual-based simulation model where a foundation species of varying genotypic diversity (number of genotypes and variability among genotypes) competes for space with subordinate species on a spatially heterogeneous lattice. Our model addresses a real and practical problem in restoration ecology: choosing the level of genetic diversity of re-introduced foundation and subordinate species. Genotypic diversity of foundation species significantly affected equilibrium community diversity, measured as species richness, either positively or negatively, depending upon environmental heterogeneity. Increases in genotypic diversity gave the foundation species a wider niche breadth. Under conditions of high environmental heterogeneity, this wider niche breadth decreased niche space for other species, lowering species richness with increased genotypic diversity until the genotypes of the foundation species saturated the landscape. With a low level of environmental heterogeneity, increasing genotypic diversity caused the foundation species niche breadth to be overdispersed, resulting in a weak positive relationship with species richness. Under these conditions, some genotypes are maladapted to the environment lowering fitness of the foundation species. These effects of genotypic diversity were secondary to the larger effects of overall foundation species fitness and environmental heterogeneity. The novel aspect of incorporating genotype diversity in combination with environmental heterogeneity in community assembly models include predictions of either positive or negative relationships between species diversity and genotypic diversity depending on environmental heterogeneity, and the conditions under which these factors are potentially relevant. Mechanistically, differential niche availability is imposed by the foundation species.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1600-0706.2011.19447.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0706.2011.19447.x}, author = {D.J. Gibson and Alstadt, A.J. and S.G. Baer and Geisler, M.} } @article {KNZ001310, title = {Intraspecific Variation in Ecophysiology of Three Dominant Prairie Grasses Used in Restoration: Cultivar Versus Non-Cultivar Population Sources}, journal = {Restoration Ecology}, volume = {19}, year = {2011}, pages = {43 -52}, abstract = {

Dominant species play crucial roles in determining plant community structure and ecosystem function. Cultivars of the dominant prairie grasses are widely used in prairie restoration and are selected for characters such as high biomass production, increased reproductive output, and stress tolerance. Genetic differences exist between cultivar and non-cultivar population sources of dominant tallgrass prairie species, which may have implications for plant performance in prairie restoration. We measured net photosynthesis (Anet), stomatal conductance (gs), and water use efficiency (WUE) in cultivar and non-cultivar dominant tallgrass prairie species Andropogon gerardii Vitman, Sorghastrum nutans (L.) Nash, and Schizachyrium scoparium (Michx.) Nash in both a greenhouse experiment and an experimental tallgrass prairie restoration. We found indicators of enhanced physiological performance (higher Anet, gs, and/or WUE) in cultivar population sources of all three dominant grass species relative to non-cultivars. For A. gerardii, cultivars exhibited higher Anet and WUE than non-cultivars. For S. nutans, cultivars exhibited higher gs, whereas non-cultivars showed higher WUE. Lastly, cultivars of S. scoparium showed higher WUE than non-cultivar population sources. Our results show that population selection of dominant species in restoration can have consequences for plant performance, which may have implications for competitive interactions that affect community structure (i.e. diversity) and ecosystem function (i.e. aboveground net primary production) during the reassembly of prairie systems.

}, keywords = {LTER-KNZ, Andropogon gerardii, Ecophysiology, photosynthesis, restoration, Schizachyrium scoparium, Sorghastrum nutans, tallgrass prairie}, doi = {10.1111/j.1526-100X.2010.00673.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1526-100X.2010.00673.x}, author = {Lambert, A.M. and S.G. Baer and D.J. Gibson} } @book {KNZ001233, title = {Grasses and Grassland Ecology}, year = {2009}, pages = {320 -}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {Oxford, UK}, keywords = {LTER-KNZ}, author = {D.J. Gibson} } @article {KNZ001092, title = {Stream insect occupancy-frequency patterns and metapopulation structure}, journal = {Oecologia}, volume = {151}, year = {2007}, pages = {313 -321}, abstract = {An understanding of the distribution patterns of organisms and the underlying factors is a fundamental goal of ecology. One commonly applied approach to visualize these is the analysis of occupancy-frequency patterns. We used data sets describing stream insect distributions from different regions of North America to analyze occupancy-frequency patterns and assess the effects of spatial scale, sampling intensity, and taxonomic resolution on these patterns. Distributions were dominated by satellite taxa (those occurring in <=10\% of sites), whereas the occurrence of core taxa (occurring in >=90\% of sites) determined the overall modality of occupancy-frequency patterns. The proportions of satellite taxa increased with spatial scale and showed positive relationships with sampling intensity (r 2=0.74{\textendash}0.96). Furthermore, analyses of data sets from New York (USA) showed that generic-level assessments underestimated the satellite class and occasionally shifted occupancy-frequency distributions from unimodal to bimodal. Our results indicate that, regardless of species- or generic-level taxonomy, stream insect communities are characterized by satellite species and that the proportion of satellite species increases with spatial scale and sampling intensity. Thus, niche-based models of occupancy-frequency patterns better characterize stream insect communities than metapopulation models such as the core-satellite species hypothesis.}, keywords = {LTER-KNZ, aquatic insect, Core-satellite, Distribution, Sampling intensity, spatial scale}, doi = {10.1007/s00442-006-0596-8}, author = {Heatherly, T. and M.R. Whiles and D.J. Gibson and Scott. L. Collins and Huryn, A.D. and Jackson, J.K. and Palmer, M.A.} } @article {KNZ001091, title = {Using local seed in prairie restoration}, journal = {Native Plants Journal}, year = {2005}, pages = {22 -28}, abstract = {Choice among local, non-local, and cultivar seeds for restoring native ecosystems is not purely an academic question{\textemdash}it also has practical consequences.In this article we summarize a series of genetic and competition studies of big bluestem (Andropogon gerardii Vitman. [Poaceae]), Indian grass (Sorghastrum nutans (L.) Nash. [Poaceae]), and purple prairie clover (Dalea purpurea Vent.[Fabaceae]) from remnant and restored Illinois (local) prairies, non-local remnant prairies, and 6 grass cultivars. We found genetic differences between local and non-local seed sources, that large populations do not necessarily have higher genetic diversity relative to small populations, and differences in plant performance could be related to seed source. Although obtaining large quantities of non-local and cultivar grass seeds may be affordable, available, and desirable given the amount of seeds required for prairie restoration, our research indicates genetic and plant performance differences between local and non-local seed sources in all 3 species. Such differences can affect both the short- and long-term success of restoration activities.}, keywords = {LTER-KNZ, Andropogon gerardii, cultivars, Dalea purpurea, Ecotype, Fabaceae, Poaceae, remnant and restored grasslands, Sorghastrum nutans}, doi = {10.2979/NPJ.2005.6.1.25}, author = {Gustafson, D.J. and D.J. Gibson and Nickrent, D.L.} } @article {KNZ00919, title = {Competitive relationships of Andropogon gerardii (big bluestem) from remnant and restored native populations and select cultivated varieties}, journal = {Functional Ecology}, volume = {18}, year = {2004}, pages = {451 -457}, abstract = {1Although genetic differentiation among plant populations is well known, its relevance for preserving the integrity of native ecosystems has received little attention. In a series of competition experiments with Andropogon gerardii Vitman, a dominant species of the North American Tallgrass Prairie, plant performance was related to seed provenance and restoration activities. 2Glasshouse experiments showed plant performance to be a function of seed source. Differential target plant performance relative to competitor identity was observed when plant performance was assessed across a range of competitor densities. Local and non-local plants were larger when competing against non-local plants relative to the local and cultivar plants, while cultivar plants were consistently larger than local and non-local plants regardless of competitor identity or density. The consistency of cultivar performance could reflect directional selection during cultivar development for consistently high fecundity, vigorous vegetative growth and resistance to pathogens. 3In a field experiment, non-local plants were half the size of local and cultivar plants, supporting recognition of seed provenances of A. gerardii based on differences in plant performance among source populations observed in the glasshouse study, and previous genetic analyses of the same populations. 4This study establishes that seed provenance and restoration activities influence the competitive ability of a dominant species which, in turn, may affect plant community structure and potential ecosystem function.}, keywords = {LTER-KNZ}, doi = {10.1111/j.0269-8463.2004.00850.x}, author = {Gustafson, D.J. and D.J. Gibson and Nickrent, D.L.} } @article {KNZ00918, title = {Conservation genetics of two co-dominant species in the endangered tallgrass prairie ecosystem}, journal = {Journal of Applied Ecology}, volume = {41}, year = {2004}, pages = {389 -397}, abstract = {

1. Global habitat fragmentation and loss of undisturbed grasslands has led to the use of non-local seed and cultivars in restoration. There is concern that these sources may be genetically depauperate and their introduction may lead to loss of unique local genotypes. Within this context we considered the issue with regard to the once widespread but now highly fragmented North American tallgrass prairie. 2. We characterized the genetic diversity and genetic relationships of the co-dominant species in this system, big bluestem Andropogon gerardii and Indian grass Sorghastrum nutans, from seven remnant and six restored local tallgrass prairies, a non-local remnant prairie, and five cultivated varieties. 3. Randomly amplified polymorphic DNA (RAPD) analysis of these grasses showed that genetic diversity was mostly retained within rather than among populations, and did not differ among restored or remnant populations or cultivars. 4. Genetic diversity estimates were not correlated with the area of the grassland, nor was there a clear association between diversity and species abundance. All of the restored grasslands in this study were established with seed from at least two local populations and were as genetically diverse as remnant sites. 5. Principal components analysis of RAPD band frequencies showed that the local remnant and restored populations were genetically different from the non-local remnant grasslands and were consistently different to the cultivars. The genetic relationships among local remnant and restored populations reflected biogeography and human activities. 6. Synthesis and applications. Restoration practitioners have often assumed that small populations are genetically depauperate and therefore the need for multiple seed sources to increase genetic diversity outweighs concerns over potential genetic differences among widespread species. Our research, however, indicates that genetic diversity is much less of an issue in these perennial outcrossing autopolyploid grasses than genetic differences among local and non-local or cultivar seed sources. Combining these results with our previous research, indicating differences in plant performance as a function of the source population, suggests that genetic differences and ecological performance among local and non-local seed sources are more of a concern than genetic diversity. Translocating non-local seed in order to increase diversity, or using cultivars, is likely to alter the genetic structure of remnant populations and potentially influence the associated community and affect ecosystem structure and function in unforeseen ways.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.0021-8901.2004.00904.x}, author = {Gustafson, D.J. and D.J. Gibson and Nickrent, D.L.} } @article {KNZ00823, title = {Genetic diversity and competitive abilities of Dalea purpurea (Fabaceae) from remnant and restored grasslands}, journal = {International Journal of Plant Science}, volume = {163}, year = {2002}, pages = {979 -990}, abstract = {Allozyme and randomly amplified polymorphic DNA (RAPD) analyses were used to characterize the genetic relationships of Dalea purpurea from remnant and restored Illinois tallgrass prairies and a large remnant tallgrass prairie in Kansas. The remnant Illinois populations were less genetically diverse than the restored Illinois populations and the Kansas population. These restored Illinois populations were established with at least two seed sources that were locally collected. There was little population divergence ( ), which is consistent with other perennial forbs, while the genetic relationships among populations reflected geographic proximity. In a greenhouse competition experiment, differences in performance between seedlings was not related to the remnant or restored status of Illinois populations, but plants from Kansas were significantly smaller than Illinois plants. Genetic diversity and competitive ability were not associated with the size of the original source population. Our data indicate that using multiple local seed sources for restoration projects will maintain the local gene pool while enhancing the regional genetic diversity of this species.}, keywords = {LTER-KNZ, conservation genetics, local seed source, restoration ecology, tallgrass prairie}, doi = {10.1086/342709}, author = {Gustafson, D.J. and D.J. Gibson and Nickert, D.L.} } @article {KNZ00689, title = {The core-satellite species hypothesis provides a theoretical basis for Grimes classification of dominant subordinate, and transient species}, journal = {Journal of Ecology}, volume = {87}, year = {1999}, pages = {1064 -1067}, keywords = {LTER-KNZ}, doi = {10.1046/j.1365-2745.1999.00424.x}, author = {D.J. Gibson and Ely, J.S. and Scott. L. Collins} } @article {KNZ00688, title = {Designs for greenhouse studies of interactions between plants}, journal = {Journal of Ecology}, volume = {87}, year = {1999}, pages = {1 -16}, abstract = {1 Designs for greenhouse studies of interactions between plants are reviewed and recommendations for their use are provided. 2 Papers published over a 10-year period showed the replacement series design to be the most popular, especially in studying crop{\textendash}weed interactions. Fifty per cent of the studies involved only two species, although studies testing the interaction between different genotypes of only a few species were also popular. 3 Limitations imposed by the choice of design, the variables measured, and the analysis used on the range of inferences that may be validly drawn from the experiment are frequently not well understood or appropriate for the questions that appear to be addressed. One example is the failure to distinguish the outcome of competition (the long-term outcome of interaction) and the effects of species on each other. 4 Studies in which only final yield is measured are severely limited as to the inferences which may be drawn. Effects due to interspecific interaction during the course of the experiment cannot then be separated from pre-existing differences, and interpretation may be biased towards species whose individuals were initially larger. In addition, measurements at several times are necessary to understand the changing dynamics of species interaction. 5 Simple pair-wise mixtures can assess the effect of treatment factors on the outcome of competition. Replacement series and related diallel designs generally produce results that may be size-biased even when initial interspecific differences are known. Additive designs (including target{\textendash}neighbour designs), despite confounding density with species proportions, offer considerable scope for addressing mechanistic questions about interspecific interactions. Designs that allow response surface analysis can avoid many of the problems inherent in the other methods, but all need to be adjusted for initial interspecific differences. Designs for multiple species experiments are still largely untested, although several designs have been used. At the level of the individual plant, hexagonal fan designs permit study of the effects of varying the spatial pattern, and the densities and the relative proportions of interacting species, but suffer from lack of independence and lack of randomization.}, keywords = {LTER-KNZ}, doi = {10.1046/j.1365-2745.1999.00321.x}, author = {D.J. Gibson and Connolly, J. and D.C. Hartnett and Weidenhamer, J.D.} } @proceedings {KNZ00487, title = {Dynamics of big bluestem (Andropogon gerardii) in ungrazed tallgrass prairie}, year = {1995}, pages = {9 -15}, keywords = {LTER-KNZ}, author = {D.J. Gibson and Towne, E.G.}, editor = {D.C. Hartnett} } @article {KNZ00482, title = {Experimental analysis of intermediate disturbance and initial floristic composition: decoupling cause and effect}, journal = {Ecology}, volume = {76}, year = {1995}, pages = {486 -492}, abstract = {The intermediate disturbance hypothesis predicts that richness will be highest in communities with moderate levels of disturbance and at intermediate time spans following disturbance. This model was proposed as a nonequilibrium explanation of species richness in tropical forests and coral reefs. A second model of succession, initial floristic composition, states that nearly all species, including late seral species, are present at the start of succession. This leads to the prediction that richness should be highest immediately following disturbance. We tested these predictions using plant species composition data from two long{\textemdash}term field experiments in North American tallgrass prairie vegetation. In contrast to one prediction of the intermediate disturbance hypothesis, there was a significant monotonic decline in species richness with increasing disturbance frequency, with no evidence of an optimum, in both field experiments. Species composition on an annually burned site was a subset of that of infrequently burned sites. The average number of species per quadrat and the number of grass, forb, and annual species were lowest on annually burned sites compared to unburned sites and sites burned once every 4 yr. The second prediction of the intermediate disturbance hypothesis, however, was supported. Richness reached a maximum at an intermediate time interval since the last disturbance. This contradicts the prediction from the initial floristic composition model of succession. These results also suggest that the two predictions of the intermediate disturbance hypothesis are independent and unrelated. We propose that this may be explained by uncoupling the effects of disturbance as a single, relatively discrete event from system response to disturbance. From this perspective, disturbance becomes an extinction{\textemdash}causing event in these grasslands, where recovery following disturbance is a balance between immigration and extinction.}, keywords = {LTER-KNZ}, doi = {10.2307/1941207}, author = {Scott. L. Collins and Glenn, S.M. and D.J. Gibson} } @article {KNZ00447, title = {Effects of mycorrhizal and plant density on yield relationships among competing tallgrass prairie grasses}, journal = {Canadian Journal of Botany}, volume = {72}, year = {1994}, pages = {168 -176}, abstract = {A replacement series experiment was used to investigate the effects of mycorrhizae, phosphorus availability, and plant density on competitive relationships between three tallgrass prairie species of varying mycorrhizal dependencies. Under mycorrhizal conditions, the obligately mycorrhizal dependent warm-season grass Andropogon gerardii (big bluestem) was a better competitor in mixture with the nonmycorrhiza-dependent cool-season grass Koeleria pyramidata (Junegrass). In the absence of mycorrhizae, however, competitive effects of big bluestem were greatly reduced and Junegrass experienced competitive release. Relative yield totals increased when mycorrhizae were suppressed, suggesting greater intensity of interspecific competition in the presence of mycorrhizae. Thus, the competitive dominance of big bluestem in tallgrass prairie is strongly related to its mycorrhizal status. Elymus canadensis (Canada wild rye) outcompeted big bluestem both with and without mycorrhizae. Relative yield totals of this species mixture were also lower under mycorrhizal conditions, indicating that mycorrhizae increase the intensity of interspecific competition between them. Relative yields of wild rye competing with big bluestem increased in the absence of mycorrhizae, suggesting that it also experiences competitive release when big blue-stem are not mycorrhizal. The outcomes of competition were generally similar among the three total plant density treatments and between P-fertilized and nonfertilized treatments. However, interactions between mycorrhizal effects and plant density confirm that outcomes of interspecific competitive interactions may be density dependent in some cases.}, keywords = {LTER-KNZ, Andropogon gerardii, arbuscular mycorrhizae, de Wit replacement series, Elymus canadensis, Koeleria pyramidata}, doi = {10.1139/b94-023}, author = {Hetrick, B.A.D. and D.C. Hartnett and G.T. Wilson and D.J. Gibson} } @article {KNZ00400, title = {Management practices in tallgrass prairie: Large- and small-scale experimental effects on species composition}, journal = {Journal of Applied Ecology}, volume = {30}, year = {1993}, pages = {247 -255}, abstract = {Many studies from grasslands have reported how differing management techniques affect production levels and species composition (e.g., Ehrenreich \& Aikman 1963; Wells 1980; Parr \& Way 1988). In most studies the main emphasis has been on a single treatment (e.g., mowing, grazing or burning) under either highly controlled small-scale, experimental conditions (Hover \& Bragg 1981; Collins 1987; Cox 1988) or less rigorous large-scale descriptive field studies (e.g., Abrams \& Hulbert 1987; Gibson \& Hulbert 1987). There are inherent strengths and weaknesses to both these approaches. Experimental studies, usually carried out at only one site or in small plots, may reflect local conditions; conversely, large-scale field observations usually lack statistical rigour (Hurlbert 1984) and treatment effects may be obscured by large-scale landscape heterogeneity (e.g. Gibson 1988a).}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1007/978-1-4612-4018-1_12}, author = {D.J. Gibson and Seastedt, T.R. and J. M. Briggs} } @article {KNZ00405, title = {VA-Mycorrhizal influence on intra- and interspecific neighbor interactions among co-occurring prairie grasses}, journal = {Journal of Ecology}, volume = {81}, year = {1993}, pages = {787 -795}, abstract = {1 A strongly obligately mycorrhiza-dependent grass, Andropogon gerardii, and a less dependent species, Elymus canadensis, were grown in intra- and interspecific combination in a target-neighbour experiment with and without mycorrhizal fungi to examine their influence on competition. 2 Mycorrhizal fungi significantly influenced the competitive effects and responses of both plant species. Strong competitive effects of Andropogon disappeared in the absence of mycorrhizas indicating that its competitive dominance in tallgrass prairie is highly dependent upon its mycorrhizal associations. The influence of mycorrhizal fungi on Andropogon responses to neighbours decreased with increasing neighbour density indicating reduced host plant benefit from mycorrhizas under crowded conditions. 3 Effects of mycorrhizas on competition were generally smaller for the less mycorrhiza-dependent Elymus. Elymus effects on target plants were not strongly affected by mycorrhizas. Elymus target plants in competition with Andropogon neighbours performed better when nonmycorrhizal, due to the lack of significant competitive suppression by Andropogon in the absence of mycorrhizas. The influence of mycorrhizal fungi on Elymus responses to Andropogon neighbours increased with increasing neighbour density. Neither mycorrhizas nor phosphorus fertilization had a significant effect on intraspecific competition among Elymus. 4 Patterns of tiller production by target plants were similar to patterns in their total dry weight, indicating that competitive and mycorrhizal effects on target plant size were primarily a result of effects on tiller numbers rather than individual tiller size. 5 The results show that mycorrhizal symbiosis can strongly influence the patterns and intensity of both intraspecific density effects and interspecific competition between co-occurring prairie grasses and that the degree of host-plant benefit derived from mycorrhizas is density dependent.}, keywords = {LTER-KNZ}, doi = {10.2307/2261676}, author = {D.C. Hartnett and Hetrick, B.A.D. and G.T. Wilson and D.J. Gibson} } @article {KNZ00359, title = {Disturbances in tallgrass prairie: local versus regional effects on community heterogeneity}, journal = {Landscape Ecology}, volume = {7}, year = {1992}, pages = {243 -252}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1007/BF00131255}, author = {Glenn, S.M. and Scott. L. Collins and D.J. Gibson} } @article {KNZ00348, title = {Effects of fire on tree spatial patterns in a tallgrass prairie landscape}, journal = {Bulletin of Torrey Botanical Club}, volume = {119}, year = {1992}, pages = {300 -307}, abstract = {

Spatial patterns of trees invading a tallgrass prairie in NE Kansas, USA were examined using a Geographical Information System. Without burning and with adequate moisture levels, the number of trees increased over a five year period by over 60\%, while in an area burned annually the number of trees decreased. Under a variety of burning regimes, Juniperus virginiana and Celtis occidentalis were significantly more uniform in their distribution pattern than Populus deltoides and Gleditsia triacanthos. In addition, three tree species (G. triacanthos, J. virginiana and U. americana) had a significant increase in the degree of aggregation with increasing tree height, while C. occidentalis showed no relationship between aggregation and tree height. There were significant associations between adult and juvenile trees at various scales, with bird dispersed J. virginiana having a higher critical distance (39 m) than wind dispersed G. triacanthos and U. americana. The spatial pattern of tree species appears to be affected by the means of dispersion; trees with wind-dispersed seeds had clumped distributions, whereas most trees with bird-dispersed seeds were regular to random in their dispersion patterns. The spatial pattern of trees invading tallgrass prairie is a function of the burning regime, dispersal vectors, habitat availability, and reproductive mode. Key words: tallgrass prairie, spatial patterns, trees, Geographical Information System

}, keywords = {LTER-KNZ, Wind}, doi = {10.2307/2996761}, author = {J. M. Briggs and D.J. Gibson} } @article {KNZ00337, title = {Controls of nitrogen limitation in tallgrass prairie}, journal = {Oecologia}, volume = {87}, year = {1991}, pages = {72 -79}, abstract = {

The relationship between fire frequency and N limitation to foliage production in tallgrass prairie was studied with a series of fire and N addition experiments. Results indicated that fire history affected the magnitude of the vegetation response to fire and to N additions. Sites not burned for over 15 years averaged only a 9\% increase in foliage biomass in response to N enrichment. In contrast, foliage production increased an average of 68\% in response to N additions on annually burned sites, while infrequencly burned sites, burned in the year of the study, averaged a 45\% increase. These findings are consistent with reports indicating that reduced plant growth on unburned prairie is due to shading and lower soil temperatures, while foliage production on frequently burned areas is constrained by N availability. Infrequent burning of unfertilized prairie therefore results in maximum production response in the year of burning relative to either annually burned or long-term unburned sites. Foliage biomass of tallgrass prairie is dominated by C4 grasses; however, forb species exhibited stronger production responses to nitrogen additions than did the grasses. After four years of annual N additions, forb biomass exceeded that of grass biomass on unburned plots, and grasses exhibited a negative response to fertilizer, probably due to competition from the forbs. The dominant C4 grasses may out-compete forbs under frequent fire conditions not only because they are better adapted to direct effects of burning, but because they can grow better under low available N regimes created by frequent fire. Key words: Andropogon gerardii, fire, nitrogen, prairie, productivity

}, keywords = {LTER-KNZ, fire;soil temperature;tallgrass prairie}, doi = {10.1007/BF00323782}, author = {Seastedt, T.R. and J. M. Briggs and D.J. Gibson} } @proceedings {KNZ00302, title = {Effects of fire exclusion on tallgrass prairie and gallery forest communities in eastern Kansas}, year = {1991}, pages = {3 -10}, publisher = {Southeastern Forest Experiment Station}, abstract = {

The purpose of this review is to synthesize a long-term body of research dealing with fire exclusion effects on tallgrass prairie and gallery forest communities on Konza Prairie in eastern Kansas. Upland and lowland prairie communities burned in spring at intervals ranging from 1-11 years were consistently dominated (79-90 percent cover) by Andropogon gerardii. With this increasing interval between fires other dominant warm-season grasses, A. scoparius and Sorghastrum nutans, had decreased cover, whereas forbs and woody species had increased cover. Aboveground biomass was higher on an annual burned versus unburned lowland prairie, due to stimulated graminoid production. Sites unburned for 10 or more years were converting to woodlands dominated by Juniperus, Ulmus, Gleditsia and Celtis. Older gallery forests occurred in stream channels and ravines and were comprised of overstory Quercus and Celtis and understory Celtis, Cercis and Ulmus. The extent of gallery forests on Konza Prairie dramatically increased from the time of European settlement (1850) to present; this has been attributed to decreased fire frequency and intensity in the region. With continued fire exclusion this century further succession in these forests has caused oak replacement by more shade tolerant species

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Abrams, M.D. and D.J. Gibson}, editor = {Nodvin, S.C. and Waldrop, T.A.} } @inbook {KNZ00330, title = {The influence of fire periodicity on habitat structure}, booktitle = {Habitat Complexity: The Physical Arrangement of Objects in Space}, year = {1991}, pages = {237 -259}, publisher = {Chapman and Hall}, organization = {Chapman and Hall}, address = {London}, abstract = {

The ecological influence of fire on the structure of a plant community varies, as fire temperature and rate of spread are neither uniform nor consistent. The manner in which a system burns depends not only on ambient temperature, windspeed, and humidity, but also on spatial distribution of fuel loads and structural variation (type, density, and height of plants) within the vegetation

}, keywords = {LTER-KNZ, fire}, author = {Mushinsky, H.R. and D.J. Gibson}, editor = {Bell, S.S. and McCoy, E.D. and Mushinsky, H.R.} } @inbook {KNZ00270, title = {Effects of fire on plant community structure in tallgrass prairie}, booktitle = {Fire in North America Tallgrass Prairies}, year = {1990}, pages = {81 -98}, publisher = {University of Oklahoma Press}, organization = {University of Oklahoma Press}, address = {Norman, OK}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Scott. L. Collins and D.J. Gibson}, editor = {Scott. L. Collins and Wallace, L.L.} } @article {KNZ00277, title = {Effects of small mammal and invertebrate herbivory on plant species richness and abundance in tallgrass prairie}, journal = {Oecologia}, volume = {84}, year = {1990}, pages = {169 -175}, abstract = {

A factorial field experiment was designed to test the effects of small mammals and above-and below-ground invertebrates on plant species richness and composition in native tallgrass prairie at Konza Prairie Research Natural Area, northeast Kansas. Over a 4-year period, Microtus ochrogaster densities were maintained by live-trapping in fenced plots, and invertebrate levels were reduced using the pesticides carbaryl for aboveground invertebrates and an organophsphate (isofenphos) for below-ground invertebrates. ANOVA according to a split-plot design of plant species biomass data harvested in 1984 and 1986 revealed few significant effect of either small mammal densities or pesticide application. Of 54 species harvested from both sample dates, only 10 were significantly affected by either treatment. Analysis of species richness according to 8 life-form classes provided a clearer pattern of response than did biomass either by species or life-form class. For example, numbers of C4 grasses were reduced by increasing small mammal densities, whereas numbers of C4 annual forbs were lowest when above-ground herbivory was reduced. While consumers have been shown to have strong effects on successional communities, the few significant results observed in this study suggests that the manipulated levels of small mammals and insects had few effects on a mature tallgrass prairie. Key words: herbivory, tallgrass prairie, small mammals, invertebrates, plant communities

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1007/BF00318268}, author = {D.J. Gibson and Freeman, C.C. and Hulbert, L.C.} } @article {KNZ00294, title = {Field bioassessment for selecting test systems to evaluate military training lands in tallgrass prairie}, journal = {Ecosystem Health.V.1 Environmental Management}, volume = {14}, year = {1990}, pages = {81 -93}, abstract = {

Ecosystems responses to physical or chemical stress may vary from changes in single organisms to alteration of the structure and function of the ecosystem. These responses to stress cannot be predicted exactly. Ecosystems repeatedly exposed to physical and/or chemical stress can be used to study the separate and combined environmental effects of stress. Such studies also allow the development of procedures to select test systems for the analysis of stress in ecosystems. A preliminary field survey of six military training sites at Fort Riley, Kansas, USA, was conducted to identify and verify ecological test systems for evaluating ecosystem responses to physical and/or chemical stress. Comparisons of these data with data collected concurrently from Konza Prairie Research Natural Area reference sites showed that soil microarthropods, some species of macroarthropods, small mammals, and native earthworm species were negatively affected by stress. In contrast, plant species diversity, plant foliage biomass, soil mycorrhizae, and many soil characteristics were within the boundaries of nominal variations observed on \"pristine\" Konza Prairie. Introduced European earthworms appeared to be positively affected by training activities. This study provided a test of systematic procedures to support impact analysis, ecological toxicology, and ecosystem risk assessment

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1007/BF02394022}, author = {Schaeffer, D.J. and Seastedt, T.R. and D.J. Gibson and D.C. Hartnett and Hetrick, B.A.D. and James, S.W. and D.W. Kaufman and Schwab, A.P. and Herricks, E.E. and Novak, E.W.} } @article {KNZ00278, title = {Fire temperature heterogeneity in contrasting fire-prone habitats: Kansas tallgrass prairie and Florida sandhills}, journal = {Bulletin of the Torrey Botanical Club}, volume = {117}, year = {1990}, pages = {349 -356}, abstract = {

Spatial patterns of fire temperatures from a tallgrass prairie and adjacent Gallery forest in northeast Kansas and a sandhill community in central Florida were recorded using temperature sensitive pyrometers. The objectives of the study were to determine, in both habitats, the range of temperatures reached during prescribed burning under a range of different conditions. Both habitats are characterized by frequent, low- intensity fires confined to the herbaceous vegetation and low shrubs. In tallgrass prairie, fire temperature maxima ranged from 19 to 399oC (n=243). The highest temperatures were associated with fires in isolated tree and shrub canopies (399oC). Fires were hotter in headfires compared with backfires (47oC difference), on lowlands compared with uplands (12oC difference), and in areas that had not been burned for many years compared with areas burned annually (34oC difference). In the Florida sandhill, fire temperature maxima ranged from 35 to 538oC (n=240), with the highest temperatures recorded at ground level in sites which had not been burned for at least 5 years. Compared with frequently burned areas, areas that have not burned for many years build up high fuel loads that support a more homogeneous, hotter fire. In the tallgrass prairie, homogeneity of fire temperatures was greatest in areas of intermediate fire frequencies. The greater spatial heterogeneity in fire characteristics of prairie with very high fire frequency (annual fire) and very low frequency (greater than 15 years between fires) is likely a result of low fuel loads and more patchy vegetation structure, respectively. In sandhill, low fuel loads and patchy distribution of fuel contribute to high spatial variability in fire temperatures in annually burned sites. Key words: fire, Florida, grassland, Kansas, sandhill, temperature

}, keywords = {LTER-KNZ, fire;gallery forest;tallgrass prairie}, doi = {10.2307/2996832}, author = {D.J. Gibson and D.C. Hartnett and Smith-Merrill, G.} } @article {KNZ00216, title = {Comparative analysis of temporal and spatial variability in aboveground production in a deciduous forest and prairie}, journal = {Holarctic Ecology}, volume = {12}, year = {1989}, pages = {130 -136}, abstract = {

Production patterns of tallgrass prairie and adjacent eastern deciduous forest were summarized for a five to seven year period. Each system responded differentially to annual or growing season rainfall and solar energy (measured by pan water evaporation). Overall, forest productivity was negatively correlated with annual precipitation; the prairie exhibited no relationship with precipitation. These differences probably reflect the lack of water limitation of the forest and the \"downstream\" position of the forest. Wood and seed production in the forest were the most variable components measured in our study. Neither variable was related to forest foliage production. Seed production in the prairie was also variable within and between years but was related to prairie foliage production. Prairie seed production was not correlated with seed production of the forest. The two ecosystems respond differentially and independently of each other within the range of climatic variation observed here. Such differences have potential significance to consumers who use both systems for habitat or resources

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1111/j.1600-0587.1989.tb00831.x}, author = {J. M. Briggs and Seastedt, T.R. and D.J. Gibson} } @article {KNZ00226, title = {Effects of animal disturbance on tallgrass prairie vegetation}, journal = {The American Midland Naturalist}, volume = {121}, year = {1989}, pages = {144 -154}, abstract = {

Plant species associated with animal disturbances (ant hills, badger mounds, pocket gopher mounds, prairie vole burrow systems and bison wallows) were examined on a tallgrass prairie in northeast Kansas. Vegetation growing on disturbed sites was a function of both the type of disturbance and the surrounding vegetation. Annuals were an important component of the flora on some disturbances, e.g., badger mounds, but on other sites, e.g., pocket gopher mounds and ant hills, common perennial prairie species were more abundant. These effects of animals illustrate the importance of disturbance in maintaining species richness and spatial heterogeneity in tallgrass prairie

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {http://www.jstor.org/stable/2425665}, author = {D.J. Gibson} } @proceedings {KNZ00224, title = {Is fire a disturbance in grasslands?}, year = {1989}, pages = {159 -161}, publisher = {University of Nebraska Press}, address = {Lincoln, NE}, abstract = {

Many grasslands, and in particular the tallgrass prairies of North America, are generally thought to be maintained by periodic fire. Semantic disagreement among researchers, however, threatens to hamper discussion of fire as an ecological force in grassland ecosystems. Some authors emphasize that fires are disturbances (or perturbations) since these fires disrupt or alter ecosystem states, trends and dynamics (e.g., accumulating nitrogen is volatilized, plant and animal communities change in composition). Other researchers point out that, because these fire-induced disruptions and alterations can maintain the status quo of the ecosystem (e.g., prevent it from becoming woodland), it is the lack of fire rather than fire itself that should be considered a disturbance. We argue that, since both points of view are useful, there is little to be gained by labeling loosely either fire or lack thereof as a \"disturbance\" in grassland ecosystems. Key Words: disturbance, fire, grasslands, perturbation, prairie, Kansas

}, keywords = {LTER-KNZ, fire}, author = {Evans, E.W. and Finck, E.J. and J. M. Briggs and D.J. Gibson and James, S.W. and D.W. Kaufman and Seastedt, T.R.}, editor = {Bragg, T.B. and Stubbendieck, J.} } @proceedings {KNZ00227, title = {Hulbert{\textquoteright}s study of factors effecting botanical composition of Tallgrass Prairie}, year = {1989}, pages = {115 -133}, publisher = {University of Nebraska Press}, address = {Lincoln, NE}, abstract = {

Lloyd Hulbert\&$\#$39;s death in May 1986 left a wealth of unfinished projects as well as the legacy of Konza Prairie Research Natural Area, Kansas. One of these was an incomplete manuscript on fire, mowing, and soil effects on the tallgrass prairie, in which canopy cover and frequency in 27 soil-treatment combinations from Konza Prairie were reported. Treatments included unburned and April burned at 1-, 2-, and 4-year intervals, annual burning during three seasons, and mowing during two seasons. Soils ranged from deep and non-rocky to shallow, rocky, silty clay loams. Late April burning favored tall C4 grasses at the expense of most forbs, whereas autumn and March burning allowed many forbs to do well. More species occurred on shallow, rocky soils than on deep soils. Annuals and biennials succeeded in mowed areas but not in burned areas. Tables of partially summarized data are included with this report so that other researchers may make use of them. Key words: tallgrass prairie, fire, mowing, soil, plant communities, species richness, Kansas

}, keywords = {LTER-KNZ, tallgrass prairie}, author = {D.J. Gibson}, editor = {Bragg, T.B. and Stubbendieck, J.} } @article {KNZ00175, title = {Regeneration and fluctuations of tallgrass prairie vegetation in response to burning frequency}, journal = {Bulletin of the Torrey Botanical Club}, volume = {115}, year = {1988}, pages = {1 -12}, abstract = {

The importance of fluctuation (non-directional irregular changes), regeneration (recovery from disturbance) and landscape heterogeneity upon a tallgrass prairie in northeast Kansas, which is prescribe burned in the spring once every 4 years, is described. All three processes were shown to be important in influencing, to varying degrees, the structure, life forms, and overall species composition. The biomass of grass, forbs and litter, and the relative abundance of different life forms were highly coupled with the burning cycle. Relative abundance of only a few species was related to the burning cycle, most species varied according to yearly climatic variation, soil type and differences between watershed units. In contrast, the frequency of a number of annual species was related to the burning cycle. Overall community patterns were related primarily to original landscape heterogeneity and secondarily to the burning cycle. Recognition of these patterns was a function of the scale of analysis. Key words: fire, fluctuations, grassland, Kansas, regeneration

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/2996561}, author = {D.J. Gibson} } @article {KNZ00176, title = {Topographic and fire effects on composition and abundance of VA-mycorrhizal fungi in tallgrass prairie}, journal = {Mycologia}, volume = {80}, year = {1988}, pages = {433 -441}, abstract = {

The species composition of vesicular- arbuscular mycorrhizal fungi (VAM) are described from experimental plots in tallgrass prairie at Konza Prairie Research Natural Area, Manhattan, Kansas. Treatments include topography (four positions downslope) and burning frequency (annually burned and infrequently burned). Multivariate and univariate analyses indicate that gradients of variation in VAM species are related primarily to topography and burning frequency, and secondarily to original plot position within experimental rows. Spore numbers of seven of the most abundant species are directly related to topography; three of these also show an interaction with burning frequency. Although the distinction between direct and indirect effects of topography and burning frequency cannot be made with these data, a parallel response of vascular plant species frequency to the topographic gradient was observed. Key words: fire, tallgrass prairie, topography, VA mycorrhizae

}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/3807844}, author = {D.J. Gibson and Hetrick, B.A.D.} } @article {KNZ00139, title = {Additions to the vascular flora of Konza Prairie Research Area, Kansas}, journal = {Transactions of the Kansas Academy of Science}, volume = {90}, year = {1987}, pages = {81 -84}, abstract = {

Fieldwork conducted on the Konza Prairie Research Natural Area (KPRNA) over the past several years has yielded a number of vascular plants previously unreported from the research site. The following list is provided as an addendum to the annotated list of vascular plants of KPRNA. These additions bring the number of species, genera, and families known from KPRNA to 467, 289, and 93, respectively. Continued research on Konza may reveal additional new taxa, however, the number of new reports would undoubtedly be few. Most of the taxa reported herein are weedy species or rare natives

}, keywords = {LTER-KNZ}, doi = {10.2307/3628116}, author = {Freeman, C.C. and D.J. Gibson} } @article {KNZ00140, title = {Effects of fire, topography and year-to-year climate variation on species composition in tallgrass prairie}, journal = {Vegetatio}, volume = {72}, year = {1987}, pages = {175 -185}, abstract = {Native unploughed tallgrass prairie from Konza Prairie, Kansas USA is described with respect to plant species compositional changes over a five year period in response to fire and topography. The principal gradient of variation in the vegetation is related to time since burning. Species show an individualistic response in terms of relative abundance to this gradient. Both the percentage of and cover of C4 species and all grasses decrease as the prairie remains unburnt. Forb and woody plant species numbers and abundance increase along this gradient. A secondary gradient of variation reflects topography (i.e. upland versus lowland soils). Upland soils support a higher species richness and diversity. Upland and lowland plant assemblages are distinct except on annually burnt prairie. The interaction between burning regime, topography and year-to-year climatic variation affects the relative abundance of the plant species differentially. The most dominant species overall, Andropogon gerardii, was affected only by year-to- year variation (i.e. climate). Its position at the top of the species abundance hierarchy was unaffected by burning regime or soil type. The other dominant species showed a suite of varying responses to these factors}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1007/BF00039839}, author = {D.J. Gibson and Hulbert, L.C.} }