02789nas a2200241   4500008004100000245014500041210006900186300001300255520201900268100002002287700001802307700001402325700001602339700001402355700002802369700001702397700001302414700001702427700001402444700001702458700001702475856005502492       2017                        eng d00aNutrient addition shifts plant community composition towards earlier flowering species in some prairie ecoregions in the U.S. Central Plains0 aNutrient addition shifts plant community composition towards ear  ae01784403 a<p>The distribution of flowering across the growing season is governed by each species&rsquo; evolutionary history and climatic variability. However, global change factors, such as eutrophication and invasion, can alter plant community composition and thus change the distribution of flowering across the growing season. We examined three ecoregions (tall-, mixed, and short-grass prairie) across the U.S. Central Plains to determine how nutrient (nitrogen (N), phosphorus, and potassium (+micronutrient)) addition alters the temporal patterns of plant flowering traits. We calculated total community flowering potential (FP) by distributing peak-season plant cover values across the growing season, allocating each species&rsquo; cover to only those months in which it typically flowers. We also generated separate FP profiles for exotic and native species and functional group. We compared the ability of the added nutrients to shift the distribution of these FP profiles (total and sub-groups) across the growing season. In all ecoregions, N increased the relative cover of both exotic species and C3 graminoids that flower in May through August. The cover of C4 graminoids decreased with added N, but the response varied by ecoregion and month. However, these functional changes only aggregated to shift the entire community&rsquo;s FP profile in the tall-grass prairie, where the relative cover of plants expected to flower in May and June increased and those that flower in September and October decreased with added N. The relatively low native cover in May and June may leave this ecoregion vulnerable to disturbance-induced invasion by exotic species that occupy this temporal niche. There was no change in the FP profile of the mixed and short-grass prairies with N addition as increased abundance of exotic species and C3 graminoids replaced other species that flower at the same time. In these communities a disturbance other than nutrient addition may be required to disrupt phenological patterns.</p>1 aBiederman, L.A.1 aMortensen, B.1 aFay, P.A.1 aHagenah, N.1 aKnops, J.1 aLa Pierre, Kimberly, J.1 aLaungani, R.1 aLind, E.1 aMcCulley, R.1 aPower, S.1 aSeabloom, E.1 aTognetti, P.  uhttp://dx.plos.org/10.1371/journal.pone.0178440ttp02091nas a2200349   4500008004100000245009600041210006900137300001400206490000700220520112600227100001501353700001601368700001701384700001401401700001701415700002101432700001601453700001501469700001301484700001701497700001801514700001601532700001901548700001401567700001801581700001801599700001401617700001601631700001601647700001601663856006201679       2013                        eng d00aLife-history constraints in grassland plant species: a growth-defence trade-off is the norm0 aLifehistory constraints in grassland plant species a growthdefen  a513 - 5210 v163 a<p>Plant growth can be limited by resource acquisition and defence against consumers, leading to contrasting trade-off possibilities. The competition-defence hypothesis posits a trade-off between competitive ability and defence against enemies (e.g. herbivores and pathogens). The growth-defence hypothesis suggests that strong competitors for nutrients are also defended against enemies, at a cost to growth rate. We tested these hypotheses using observations of 706 plant populations of over 500 species before and following identical fertilisation and fencing treatments at 39 grassland sites worldwide. Strong positive covariance in species responses to both treatments provided support for a growth-defence trade-off: populations that increased with the removal of nutrient limitation (poor competitors) also increased following removal of consumers. This result held globally across 4 years within plant life-history groups and within the majority of individual sites. Thus, a growth-defence trade-off appears to be the norm, and mechanisms maintaining grassland biodiversity may operate within this constraint.</p>1 aLind, E.M.1 aBorer, E.T.1 aSeabloom, E.1 aAdler, P.1 aBakker, J.D.1 aBlumenthal, D.M.1 aCrawley, M.1 aDavies, K.1 aFirn, J.1 aGruner, D.S.1 aHarpole, W.S.1 aHautier, Y.1 aHillebrand, H.1 aKnops, J.1 aMelbourne, B.1 aMortensen, B.1 aRisch, A.1 aSchuetz, M.1 aStevens, C.1 aWragg, P.D.  uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/ele.1207801991nas a2200265   4500008004100000245007900041210006900120300001300189490000700202520119800209100001601407700001901423700001601442700001701458700001901475700001401494700001501508700001701523700001501540700001701555700001401572700001601586700001701602856010601619       2007                        eng d00aDoes species diversity limitproductivity in natural grassland communities?0 aDoes species diversity limitproductivity in natural grassland co  a680 -6890 v103 aTheoretical analyses and experimental studies of synthesized assemblages indicate that under particular circumstances species diversity can enhance community productivity through niche complementarity. It remains unclear whether this process has important effects in mature natural ecosystems where competitive feedbacks and complex environmental influences affect diversity–productivity relationships. In this study, we evaluated diversity–productivity relationships while statistically controlling for environmental influences in 12 natural grassland ecosystems. Because diversity–productivity relationships are conspicuously nonlinear, we developed a nonlinear structural equation modeling (SEM) methodology to separate the effects of diversity on productivity from the effects of productivity on diversity. Meta-analysis was used to summarize the SEM findings across studies. While competitive effects were readily detected, enhancement of production by diversity was not. These results suggest that the influence of small-scale diversity on productivity in mature natural systems is a weak force, both in absolute terms and relative to the effects of other controls on productivity.1 aGrace, J.B.1 aAnderson, T.M.1 aSmith, M.D.1 aSeabloom, E.1 aAndelman, S.J.1 aMeche, G.1 aWeiher, E.1 aAllain, L.K.1 aJutila, H.1 aSankaran, M.1 aKnops, J.1 aRitchie, M.1 aWhiles, M.R.  uhttp://knz.lternet.edu/content/does-species-diversity-limitproductivity-natural-grassland-communities