03012nas a2200265   4500008004100000245011300041210006900154300000900223490000600232520219900238653001802437653002402455653001402479653002202493653002102515653002802536653001702564653001502581653001602596653002302612653001402635100001702649700002002666856006002686       2013                        eng d00aSeed source has variable effects on species, communities, and ecosystem properties in grassland restorations0 aSeed source has variable effects on species communities and ecos  a93 -0 v43 aResearch to date regarding the relative advantages of local versus non-local sources of plantmaterial for restoration has produced equivocal results. This research has typically focused on theperformance of individual species at individual locations and without addressing higher order communityand ecosystem properties. We investigated the effects of seed source (local, non-local, and mixed-sourcetreatments) on species, community, and ecosystem properties under a range of environmental conditionsusing reciprocal common gardens at locations in three states (Nebraska, Kansas, and Oklahoma). In orderto mimic the restoration of grassland vegetation under realistic conditions where multiple species interactwith one another during establishment, we seeded twelve species together between December, 2009 andJanuary, 2010, and assessed responses in 2010, 2011, and 2012. Both common garden location and seedsource affected the establishment of individual species (measured as species-specific biomass), butresponses were not consistent among species. No seed source had a consistent advantage across all sites oracross all species. In a few cases, the local source was most productive for a particular species at onelocation, but no species showed a consistent local advantage across locations or years. Rather, in two out ofthree species that exhibited a local advantage at one location, the same source was also the most productiveat a non-local site. Community structure and species richness differed among locations in all years, butsource did not significantly affect seeded species richness, and source only affected community structure in2011. Despite source effects on individual species and community structure, seed source had no significanteffects on the combined productivity of seeded species. These results do not support the targeted use oflocal sources when the establishment of sown species and primary productivity are restoration objectives.Using mixed-source species mixtures may increase chances of restoration success, given the idiosyncrasy ofindividual species’ responses among locations and potential site-specific environmental changes likely tooccur in the future.10acommon garden10acommunity structure10adispersal10agenetic diversity10alocal adaptation10amanaged relocationplant10aproductivity10aprovenance10arestoration10aseed transfer zone10atallgrass1 aCarter, D.L.1 aBlair, John, M.  uhttp://www.esajournals.org/doi/pdf/10.1890/ES13-00090.102310nas a2200205   4500008004100000245008900041210006900130300001100199490000700210520162200217653001901839653002401858653001301882653001801895653002201913100001501935700002001950700001901970856011501989       1999                        eng d00aEffects of altered soil water availability on a tallgrass prairie nematode community0 aEffects of altered soil water availability on a tallgrass prairi  a45 -550 v133 aClimate change predictions for the Great Plains region of North America include reduced growing season precipitation. The consequence of this prediction for soil fauna and belowground processes was investigated at two spatial scales by integrating experimental manipulation of soil moisture levels with natural variation in soil-water availability. Experiments consisted of (1) reciprocal core transplants across a regional precipitation gradient and (2) supplemental irrigation applied across a local topographic gradient. This report examines functional-level responses by the tallgrass prairie nematode community to differences in soil moisture levels over a four-year period. Effects on nematode community structure were complex and dependent upon nematode trophic habit and depth in the soil profile. The strongest and most consistent responses to changes in soil-water availability were displayed by herbivorous taxa, with 71% higher densities observed under wetter soil conditions across experiments and years. Responses of microbial-feeding nematodes were more variable, with lower densities observed, in some cases, in the presence of experimentally-increased soil moisture levels. Effects of regional differences in soil-water availability on the nematode community were uniformly restricted to depths >20 cm. Community responses to short-term changes in soil moisture were not consistent with patterns in community structure developed under different natural moisture regimes, suggesting divergent short-term and long-term responses of belowground biota and processes to changes in soil-water availability.10aClimate change10acommunity structure10aNematode10asoil moisture10atallgrass prairie1 aTodd, T.C.1 aBlair, John, M.1 aMilliken, G.A.  uhttp://lter.konza.ksu.edu/content/effects-altered-soil-water-availability-tallgrass-prairie-nematode-community02318nas a2200193   4500008004100000245010400041210006900145300001300214490000800227520163200235653002401867653001601891653001901907653001401926653001701940100001601957700002001973856013101993       1999                        eng d00aExotic plant species in a C4-dominated grassland: Invasibility, disturbance and community structure0 aExotic plant species in a C4dominated grassland Invasibility dis  a605 -6120 v1203 aWe used data from a 15-year experiment in a C4-dominated grassland to address the effects of community structure (i.e., plant species richness, dominance) and disturbance on invasibility, as measured by abundance and richness of exotic species. Our specific objectives were to assess the temporal and spatial patterns of exotic plant species in a native grassland in Kansas (USA) and to determine the factors that control exotic species abundance and richness (i.e., invasibility). Exotic species (90% C3 plants) comprised approximately 10% of the flora, and their turnover was relatively high (30%) over the 15-year period. We found that disturbances significantly affected the abundance and richness of exotic species. In particular, long-term annually burned watersheds had lower cover of exotic species than unburned watersheds, and fire reduced exotic species richness by 80–90%. Exotic and native species richness were positively correlated across sites subjected to different fire (r = 0.72) and grazing (r = 0.67) treatments, and the number of exotic species was lowest on sites with the highest productivity of C4 grasses (i.e., high dominance). These results provide strong evidence for the role of community structure, as affected by disturbance, in determining invasibility of this grassland. Moreover, a significant positive relationship between exotic and native species richness was observed within a disturbance regime (annually burned sites, r = 0.51; unburned sites, r = 0.59). Thus, invasibility of this C4-dominated grassland can also be directly related to community structure independent of disturbance.10acommunity structure10adisturbance10aexotic species10agrassland10aInvasibility1 aSmith, M.D.1 aKnapp, Alan, K.  uhttp://lter.konza.ksu.edu/content/exotic-plant-species-c4-dominated-grassland-invasibility-disturbance-and-community-structure02278nas a2200193   4500008004100000245003900041210003500080300001300115490000600128520173000134653002401864653002001888653002201908653002701930100002401957700001601981700001801997856006902015       1993                        eng d00aThe hierarchical continuum concept0 ahierarchical continuum concept  a149 -1560 v43 aTwo general models have been proposed to explain the structure of the plant community: the community-unit model of Clements and the continuum model of Whittaker and Curtis, the latter based on Gleason's individualistic distribution of species. It is generally assumed that most ecologists now accept the continuum model. Empirical evidence suggests, however, that the continuum in its current form does not fully describe the observed patterns of vegetation along environmental gradients. In this paper, we introduce the hierarchical continuum as a general concept to represent dynamic community structure along regional spatial gradients. The hierarchical continuum is derived from a combination of the individualistic distribution of species, hierarchical assemblage structure, and the core-satellite species hypothesis. The hierarchical continuum concept predicts that the distribution of species across sites in a region will be polymodal, which reflects hierarchical structure, and that the distribution and abundance of species within and between sites will be spatially and temporally dynamic. Regional distribution of plant species in North American tallgrass prairie, southeastern flood-plain hardwood forests, northern upland hardwood forests, and boreal forests were either bimodal or polymodal as predicted by the hierarchical continuum concept. Species in tallgrass prairie were spatially and temporally dynamic with an average turnover of 8–9 species per 50 m2 yr1. In addition, the hierarchical continuum concept predicts the potential for fractal (self-similar) patterns of community structure, and provides a framework for testable hypotheses concerning species distributions along environmental gradients.10acommunity structure10aContinuum model10aGradient analysis10aHierarchical structure1 aCollins, Scott., L.1 aGlenn, S.M.1 aRoberts, D.W.  uhttp://lter.konza.ksu.edu/content/hierarchical-continuum-concept