@article {KNZ001787, title = {Integrative modelling reveals mechanisms linking productivity and plant species richness}, journal = {Nature}, volume = {529}, year = {2016}, pages = {390 - 393}, abstract = {

How ecosystem productivity and species richness are interrelated is one of the most debated subjects in the history of ecology1. Decades of intensive study have yet to discern the actual mechanisms behind observed global patterns2, 3. Here, by integrating the predictions from multiple theories into a single model and using data from 1,126 grassland plots spanning five continents, we detect the clear signals of numerous underlying mechanisms linking productivity and richness. We find that an integrative model has substantially higher explanatory power than traditional bivariate analyses. In addition, the specific results unveil several surprising findings that conflict with classical models4, 5, 6, 7. These include the isolation of a strong and consistent enhancement of productivity by richness, an effect in striking contrast with superficial data patterns. Also revealed is a consistent importance of competition across the full range of productivity values, in direct conflict with some (but not all) proposed models. The promotion of local richness by macroecological gradients in climatic favourability, generally seen as a competing hypothesis8, is also found to be important in our analysis. The results demonstrate that an integrative modelling approach leads to a major advance in our ability to discern the underlying processes operating in ecological systems.

}, keywords = {LTER-KNZ}, doi = {10.1038/nature16524}, url = {https://www.nature.com/articles/nature16524}, author = {Grace, J.B. and Anderson, T.M. and Seabloom, E.W. and E.T. Borer and P. Adler and Harpole, W.S. and Hautier, Y. and Hillebrand, H. and Lind, E.M. and P{\"a}rtel, M. and J.D. Bakker and Buckley, Y.M. and Crawley, M.J. and Damschen, E.I. and Davies, K.F. and Fay, P.A. and Firn, J. and Gruner, D.S. and Hector, A. and Knops, J.M.H. and MacDougall, A.S. and Melbourne, B.A. and J.W. Morgan and Orrock, J.L. and Prober, S.M. and M.D. Smith} } @article {KNZ001698, title = {Anthropogenic nitrogen deposition predicts local grassland primary production worldwide}, journal = {Ecology}, volume = {96}, year = {2015}, pages = {1459 -1465}, abstract = {

Humans dominate many important Earth system processes including the nitrogen (N) cycle. Atmospheric N deposition affects fundamental processes such as carbon cycling, climate regulation, and biodiversity, and could result in changes to fundamental Earth system processes such as primary production. Both modelling and experimentation have suggested a role for anthropogenically altered N deposition in increasing productivity, nevertheless, current understanding of the relative strength of N deposition with respect to other controls on production such as edaphic conditions and climate is limited. Here we use an international multiscale data set to show that atmospheric N deposition is positively correlated to aboveground net primary production (ANPP) observed at the 1-m2 level across a wide range of herbaceous ecosystems. N deposition was a better predictor than climatic drivers and local soil conditions, explaining 16\% of observed variation in ANPP globally with an increase of 1 kg N\·ha\−1\·yr\−1 increasing ANPP by 3\%. Soil pH explained 8\% of observed variation in ANPP while climatic drivers showed no significant relationship. Our results illustrate that the incorporation of global N deposition patterns in Earth system models are likely to substantially improve estimates of primary production in herbaceous systems. In herbaceous systems across the world, humans appear to be partially driving local ANPP through impacts on the N cycle.

}, keywords = {LTER-KNZ}, doi = {http://dx.doi.org/10.1890/14-1902.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/14-1902.1}, author = {Stevens, C.J. and Lind, E.M. and Hautier, Y. and Harpole, W.S. and E.T. Borer and Hobbie, S. and Seabloom, E.Q. and L. Ladwig and J.D. Bakker and Chu, C. and Scott. L. Collins and Davies, K.F. and Firn, J. and Hillebrand, H. and Kimberly J. La Pierre and MacDougall, A.S. and Melbourne, B.A. and McCulley, R.L. and J.W. Morgan and Orrock, J.L. and Prober, S.M. and A. Risch and Schultz, M. and Wragg, P.D.} } @article {KNZ001789, title = {Consistent responses of soil microbial communities to elevated nutrient inputs in grasslands across the globe}, journal = {Proceedings of the National Academy of Sciences}, volume = {112}, year = {2015}, pages = {10967 - 10972}, abstract = {

Soil microorganisms are critical to ecosystem functioning and the maintenance of soil fertility. However, despite global increases in the inputs of nitrogen (N) and phosphorus (P) to ecosystems due to human activities, we lack a predictive understanding of how microbial communities respond to elevated nutrient inputs across environmental gradients. Here we used high-throughput sequencing of marker genes to elucidate the responses of soil fungal, archaeal, and bacterial communities using an N and P addition experiment replicated at 25 globally distributed grassland sites. We also sequenced metagenomes from a subset of the sites to determine how the functional attributes of bacterial communities change in response to elevated nutrients. Despite strong compositional differences across sites, microbial communities shifted in a consistent manner with N or P additions, and the magnitude of these shifts was related to the magnitude of plant community responses to nutrient inputs. Mycorrhizal fungi and methanogenic archaea decreased in relative abundance with nutrient additions, as did the relative abundances of oligotrophic bacterial taxa. The metagenomic data provided additional evidence for this shift in bacterial life history strategies because nutrient additions decreased the average genome sizes of the bacterial community members and elicited changes in the relative abundances of representative functional genes. Our results suggest that elevated N and P inputs lead to predictable shifts in the taxonomic and functional traits of soil microbial communities, including increases in the relative abundances of faster-growing, copiotrophic bacterial taxa, with these shifts likely to impact belowground ecosystems worldwide.

}, keywords = {LTER-KNZ, Fertilization, shotgun metagenomics, Soil bacteria, Soil ecology, Soil fungi}, doi = {10.1073/pnas.1508382112}, url = {https://www.pnas.org/content/112/35/10967}, author = {Leff, J.W. and Jones, S.E. and Prober, S.M. and Barber{\'a}n, A. and E.T. Borer and Firn, J.L. and Harpole, W.S. and Hobbie, S.E. and Hofmockel, K.S. and Knops, J.M.H. and McCulley, R.L. and Kimberly J. La Pierre and A. Risch and Seabloom, E.W. and Sch{\"u}tz, Martin and Steenbock, C. and Stevens, C.J. and Fierer, N.} } @article {KNZ001788, title = {Grassland productivity limited by multiple nutrients}, journal = {Nature Plants}, volume = {1}, year = {2015}, pages = {15080}, abstract = {

Terrestrial ecosystem productivity is widely accepted to be nutrient limited1. Although nitrogen (N) is deemed a key determinant of aboveground net primary production (ANPP)2,3, the prevalence of co-limitation by N and phosphorus (P) is increasingly recognized4,​5,​6,​7,​8. However, the extent to which terrestrial productivity is co-limited by nutrients other than N and P has remained unclear. Here, we report results from a standardized factorial nutrient addition experiment, in which we added N, P and potassium (K) combined with a selection of micronutrients (K+μ), alone or in concert, to 42 grassland sites spanning five continents, and monitored ANPP. Nutrient availability limited productivity at 31 of the 42 grassland sites. And pairwise combinations of N, P, and K+μ co-limited ANPP at 29 of the sites. Nitrogen limitation peaked in cool, high latitude sites. Our findings highlight the importance of less studied nutrients, such as K and micronutrients, for grassland productivity, and point to significant variations in the type and degree of nutrient limitation. We suggest that multiple-nutrient constraints must be considered when assessing the ecosystem-scale consequences of nutrient enrichment.

}, keywords = {LTER-KNZ}, doi = {10.1038/nplants.2015.80}, url = {https://www.nature.com/articles/nplants201580}, author = {Fay, P.A. and Prober, S.M. and Harpole, W.S. and Knops, J.M.H. and J.D. Bakker and E.T. Borer and Lind, E.M. and MacDougall, A.S. and Seabloom, E.W. and Wragg, P.D. and P. Adler and D.M. Blumenthal and Buckley, Y.M. and Chu, C. and Cleland, E.E. and Scott. L. Collins and Davies, K.F. and G. Du and Feng, X. and Firn, J. and Gruner, D.S. and Hagenah, N. and Hautier, Y. and Heckman, R.W. and Jin, V.L. and Kirkman, K.P. and Klein, J. and L. Ladwig and Li, Q. and McCulley, R.L. and Melbourne, B.A. and Mitchell, C.E. and Joslin L. Moore and J.W. Morgan and A. Risch and sch{\"u}tz, M. and Stevens, C.J. and Wedin, D.A. and Yang, L.H.} } @article {KNZ001678, title = {Plant diversity predicts beta but not alpha diversity of soil microbes across grasslands worldwide}, journal = {Ecology Letters}, volume = {18}, year = {2015}, pages = {85 -95}, abstract = {

Aboveground\–belowground interactions exert critical controls on the composition and function of terrestrial ecosystems, yet the fundamental relationships between plant diversity and soil microbial diversity remain elusive. Theory predicts predominantly positive associations but tests within single sites have shown variable relationships, and associations between plant and microbial diversity across broad spatial scales remain largely unexplored. We compared the diversity of plant, bacterial, archaeal and fungal communities in one hundred and forty-five 1 m2 plots across 25 temperate grassland sites from four continents. Across sites, the plant alpha diversity patterns were poorly related to those observed for any soil microbial group. However, plant beta diversity (compositional dissimilarity between sites) was significantly correlated with the beta diversity of bacterial and fungal communities, even after controlling for environmental factors. Thus, across a global range of temperate grasslands, plant diversity can predict patterns in the composition of soil microbial communities, but not patterns in alpha diversity.

}, keywords = {LTER-KNZ}, doi = {10.1111/ele.12381}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.12381}, author = {Prober, S.M. and Leff, J.W. and Bates, S.T. and E.T. Borer and Firn, J. and Harpole, W.S. and Lind, E.M. and Seabloom, E.W. and P. Adler and J.D. Bakker and E.E Cleland and DeCrappeo, N.M. and DeLorenze, E. and Hagenah, N. and Hautier, Y. and Hofmockel, K.S. and Kirkman, K.P. and Knops, J.M.H. and Kimberly J. La Pierre and MacDougall, A.S. and McCulley, R.L. and Mitchell, C.E. and A. Risch and Schuetz, M. and Stevens, C.J. and Williams, R.J. and Fierer, N.} } @article {KNZ001697, title = {Plant species{\textquoteright} origin predicts dominance and response to nutrient enrichment and herbivores in global grasslands}, journal = {Nature Communications}, volume = {6}, year = {2015}, pages = {7710 -}, abstract = {

Exotic species dominate many communities; however the functional significance of species\’ biogeographic origin remains highly contentious. This debate is fuelled in part by the lack of globally replicated, systematic data assessing the relationship between species provenance, function and response to perturbations. We examined the abundance of native and exotic plant species at 64 grasslands in 13 countries, and at a subset of the sites we experimentally tested native and exotic species responses to two fundamental drivers of invasion, mineral nutrient supplies and vertebrate herbivory. Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands.

}, keywords = {LTER-KNZ, Biological sciences, ecology, Plant sciences}, doi = {10.1038/ncomms8710}, url = {https://www.nature.com/articles/ncomms8710}, author = {Seabloom, E.W. and E.T. Borer and Buckley, Y. and Cleland, E.E. and Davies, K.F. and Firn, J. and Harpole, W.S. and Hautier, Y. and Lind, E. and MacDougall, A.S. and Orrock, J.L. and Prober, S.M. and P. Adler and Anderson, T.M. and J.D. Bakker and L.A. Biederman and D.M. Blumenthal and C.S. Brown and Brudvig, L.A. and Cadotte, M. and Chu, C. and Cottingham, K.L. and Crawley, M.J. and Damschen, E.I. and D{\textquoteright}Antonio, C.M. and CeCrappeo, N.M. and G. Du and Fay, P.A. and Frater, P. and Gruner, D.S. and Hagenah, N. and Hector, A. and Hillebrand, H. and Hofmockel, K.S. and Humphries, H.C. and Jin, V.L. and Kay, A.D. and Kirkman, K.P. and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and L. Ladwig and Lambrinos, J.G. and Li, Q. and Li, W. and Marushia, R.} } @article {KNZ001792, title = {Anthropogenic-based regional-scale factors most consistently explain plot-level exotic diversity in grasslands}, journal = {Global Ecology and Biogeography}, volume = {23}, year = {2014}, pages = {802 - 810}, abstract = {

Aim Evidence linking the accumulation of exotic species to the suppression of native diversity is equivocal, often relying on data from studies that have used different methods. Plot-level studies often attribute inverse relationships between native and exotic diversity to competition, but regional abiotic filters, including anthropogenic influences, can produce similar patterns. We seek to test these alternatives using identical scale-dependent sampling protocols in multiple grasslands on two continents. Location Thirty-two grassland sites in North America and Australia. Methods We use multiscale observational data, collected identically in grain and extent at each site, to test the association of local and regional factors with the plot-level richness and abundance of native and exotic plants. Sites captured environmental and anthropogenic gradients including land-use intensity, human population density, light and soil resources, climate and elevation. Site selection occurred independently of exotic diversity, meaning that the numbers of exotic species varied randomly thereby reducing potential biases if only highly invaded sites were chosen. Results Regional factors associated directly or indirectly with human activity had the strongest associations with plot-level diversity. These regional drivers had divergent effects: urban-based economic activity was associated with high exotic\ :\ native diversity ratios; climate- and landscape-based indicators of lower human population density were associated with low exotic\ :\ native ratios. Negative correlations between plot-level native and exotic diversity, a potential signature of competitive interactions, were not prevalent; this result did not change along gradients of productivity or heterogeneity. Main conclusion We show that plot-level diversity of native and exotic plants are more consistently associated with regional-scale factors relating to urbanization and climate suitability than measures indicative of competition. These findings clarify the long-standing difficulty in resolving drivers of exotic diversity using single-factor mechanisms, suggesting that multiple interacting anthropogenic-based processes best explain the accumulation of exotic diversity in modern landscapes.

}, keywords = {LTER-KNZ}, doi = {10.1111/geb.12157}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.12157}, author = {MacDougall, A.S. and Bennett, J.R. and Firn, J. and Seabloom, E.W. and E.T. Borer and Lind, E.M. and Orrock, J.L. and Harpole, W.S. and Hautier, Y. and P. Adler and Cleland, E. and Davies, K. and Melbourne, B. and Prober, S.M. and J.D. Bakker and Fay, P.A. and Jin, V.L. and Kendig, A. and Kimberly J. La Pierre and Joslin L. Moore and J.W. Morgan and Stevens, C.J.} } @article {KNZ001632, title = {Eutrophication weakens stabilizing effects of diversity in natural grasslands}, journal = {Nature}, volume = {508}, year = {2014}, pages = {521 -525}, abstract = {

Studies of experimental grassland communities1, 2, 3, 4, 5, 6, 7 have demonstrated that plant diversity can stabilize productivity through species asynchrony, in which decreases in the biomass of some species are compensated for by increases in others1, 2. However, it remains unknown whether these findings are relevant to natural ecosystems, especially those for which species diversity is threatened by anthropogenic global change8, 9, 10, 11. Here we analyse diversity\–stability relationships from 41 grasslands on five continents and examine how these relationships are affected by chronic fertilization, one of the strongest drivers of species loss globally8. Unmanipulated communities with more species had greater species asynchrony, resulting in more stable biomass production, generalizing a result from biodiversity experiments to real-world grasslands. However, fertilization weakened the positive effect of diversity on stability. Contrary to expectations, this was not due to species loss after eutrophication but rather to an increase in the temporal variation of productivity in combination with a decrease in species asynchrony in diverse communities. Our results demonstrate separate and synergistic effects of diversity and eutrophication on stability, emphasizing the need to understand how drivers of global change interactively affect the reliable provisioning of ecosystem services in real-world systems.

}, keywords = {LTER-KNZ, Biodiversity, Community ecology, Grassland ecology}, doi = {10.1038/nature13014}, url = {https://www.nature.com/articles/nature13014}, author = {Hautier, Y. and Seabloom, E.W. and E.T. Borer and P. Adler and Harpole, W.S. and Hillebrand, H. and Lind, E.M. and MacDougall, A.S. and Stevens, C.J. and J.D. Bakker and Buckley, Y.M. and Chu, C. and Scott. L. Collins and Daleo, P. and Damschen, E.I. and Davies, K.F. and Fay, P.A. and Firn, J. and Gruner, D.S. and Jin, V.L. and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and Li, W. and McCulley, R.L. and Melbourne, B.A. and Joslin L. Moore and O{\textquoteright}Halloran, L.R. and Prober, S.M. and A. Risch and Sankaran, M. and Schuetz, M. and Hector, A.} } @article {KNZ001791, title = {Life-history constraints in grassland plant species: a growth-defence trade-off is the norm}, journal = {Ecology Letters}, volume = {16}, year = {2013}, pages = {513 - 521}, abstract = {

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.

}, keywords = {LTER-KNZ}, doi = {10.1111/ele.12078}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.12078}, author = {Lind, E.M. and E.T. Borer and Seabloom, E. and P. Adler and J.D. Bakker and D.M. Blumenthal and Crawley, M. and Davies, K. and Firn, J. and Gruner, D.S. and Harpole, W.S. and Hautier, Y. and Hillebrand, H. and Knops, J. and Melbourne, B. and Mortensen, B. and A. Risch and Schuetz, M. and Stevens, C. and Wragg, P.D.} } @article {KNZ001790, title = {Predicting invasion in grassland ecosystems: is exotic dominance the real embarrassment of richness?}, journal = {Global Change Biology}, volume = {19}, year = {2013}, pages = {3677 - 3687}, abstract = {

Invasions have increased the size of regional species pools, but are typically assumed to reduce native diversity. However, global-scale tests of this assumption have been elusive because of the focus on exotic species richness, rather than relative abundance. This is problematic because low invader richness can indicate invasion resistance by the native community or, alternatively, dominance by a single exotic species. Here, we used a globally replicated study to quantify relationships between exotic richness and abundance in grass-dominated ecosystems in 13 countries on six continents, ranging from salt marshes to alpine tundra. We tested effects of human land use, native community diversity, herbivore pressure, and nutrient limitation on exotic plant dominance. Despite its widespread use, exotic richness was a poor proxy for exotic dominance at low exotic richness, because sites that contained few exotic species ranged from relatively pristine (low exotic richness and cover) to almost completely exotic-dominated ones (low exotic richness but high exotic cover). Both exotic cover and richness were predicted by native plant diversity (native grass richness) and land use (distance to cultivation). Although climate was important for predicting both exotic cover and richness, climatic factors predicting cover (precipitation variability) differed from those predicting richness (maximum temperature and mean temperature in the wettest quarter). Herbivory and nutrient limitation did not predict exotic richness or cover. Exotic dominance was greatest in areas with low native grass richness at the site- or regional-scale. Although this could reflect native grass displacement, a lack of biotic resistance is a more likely explanation, given that grasses comprise the most aggressive invaders. These findings underscore the need to move beyond richness as a surrogate for the extent of invasion, because this metric confounds monodominance with invasion resistance. Monitoring species\&$\#$39; relative abundance will more rapidly advance our understanding of invasions.

}, keywords = {LTER-KNZ}, doi = {10.1111/gcb.12370}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12370}, author = {Seabloom, E.W. and E.T. Borer and Buckley, Y. and Cleland, E.E. and Davies, K. and Firn, J. and Harpole, W.S. and Hautier, Y. and Lind, E. and MacDougall, A. and Orrock, J.L. and Prober, S.M. and P. Adler and J. Alberti and Anderson, M.T. and J.D. Bakker and L.A. Biederman and D.M. Blumenthal and C.S. Brown and Brudvig, L.A. and Caldeira, M. and Chu, C. and Crawley, M.J. and Daleo, P. and Damschen, E.I. and D{\textquoteright}Antonio, C.M. and DeCrappeo, N.M. and Dickman, C.R. and G. Du and Fay, P.A. and Frater, P. and Gruner, D.S. and Hagenah, N. and Hector, A. and Helm, A. and Hillebrand, H. and Hofmockel, K.S. and Humphries, H.C. and Iribarne, O. and Jin, V.L. and Kay, A. and Kirkman, K.P. and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and L. Ladwig and Lambrinos, J.G. and Leakey, A.D.B. and Li, Q. and Li, W. and McCulley, R. and Melbourne, B. and Mitchell, C.E. and Joslin L. Moore and J.W. Morgan and Mortensen, B. and O{\textquoteright}Halloran, L.R. and P{\"a}rtel, M. and Pascual, J and Pyke, D.A. and A. Risch and Salguero-Gomez, R. and Sankaran, M. and Schuetz, M. and Simonsen, A. and M.D. Smith and Stevens, C. and Sullivan, L. and Wardle, G.M. and Wolkovich, E.M. and Wragg, P.D. and Wright, J. and Yang, L.} } @article {KNZ001455, title = {Abundance of introduced species at home predicts abundance away in herbaceous communities}, journal = {Ecology Letters}, volume = {14}, year = {2011}, pages = {274 -281}, keywords = {LTER-KNZ}, doi = {10.1111/j.1461-0248.2010.01584.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1461-0248.2010.01584.x}, author = {Firn, J. and Joslin L. Moore and MacDougall, A.S. and E.T. Borer and Seabloom, E.W. and HilleRisLambers, J. and Harpole, W.S. and Cleland, E.E. and C.S. Brown and Knops, J.M.H. and Prober, S.M. and Pyke, D.A. and Farrell, K.A. and J.D. Bakker and O{\textquoteright}Halloran, L.R. and P. Adler and Scott. L. Collins and D{\textquoteright}Antonio, C.M. and Crawley, M.J. and Wolkovich, E.M. and Kimberly J. La Pierre and Melbourne, B.A. and Hautier, Y. and J.W. Morgan and Leakey, A.D.B. and Kay, A.D. and McCulley, R. and Davies, K.F. and Stevens, C.J. and Chu, C. and Holl, K.D. and Klein, J.A. and Fay, P.A. and Hagenah, N. and Kirkman, K.P. and Buckley, Y.M.} } @article {KNZ001448, title = {Productivity is a poor predictor of plant species richness}, journal = {Science}, volume = {333}, year = {2011}, pages = {1750 -1753}, abstract = {

For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent meta-analyses questioned the generality of hump-shaped patterns, these syntheses have been criticized for failing to account for methodological differences among studies. We addressed such concerns by conducting standardized sampling in 48 herbaceous-dominated plant communities on five continents. We found no clear relationship between productivity and fine-scale (meters\−2) richness within sites, within regions, or across the globe. Ecologists should focus on fresh, mechanistic approaches to understanding the multivariate links between productivity and richness.

}, keywords = {LTER-KNZ}, doi = {10.1126/science.1204498}, url = {http://science.sciencemag.org/content/333/6050/1750}, author = {P. Adler and Seabloom, E.W. and E.T. Borer and Hillebrand, H. and Hautier, Y. and Hector, A. and Harpole, W.S. and O{\textquoteright}Halloran, L.R. and Grace, J.B. and Anderson, T.M. and J.D. Bakker and L.A. Biederman and C.S. Brown and Buckley, Y.M. and Calabrese, L.B. and Chu, C.J. and Cleland, E.E. and Scott. L. Collins and Cottingham, K.L. and Crawley, M.J. and Damschen, E.I. and Davies, K.F. and DeCrappeo, N.M. and Fay, P.A. and Firn, J. and Frater, P. and Gasarch, E.I. and Gruner, D.S. and Hagenah, N. and HilleRisLambers, J. and Humphries, H.C. and Jin, V.L. and Kay, A. and Kirkman, K.P. and Klein, J.A. and Knops, J.M.H. and Kimberly J. La Pierre and Lambrinos, J.G. and Li, W. and MacDougall, A.S. and McCulley, R.L. and Melbourne, B.A. and Mitchell, C.E. and Joslin L. Moore} } @article {KNZ001048, title = {Non-neutral patterns of species abundance in grassland communities}, journal = {Ecology Letters}, volume = {9}, year = {2006}, pages = {15 -23}, abstract = {Although the distribution of plant species abundance in a Minnesota grassland was consistent with neutral theory, niche but not neutral mechanisms were supported by the ability of species traits to predict species abundances in three experimental grassland communities. In particular, data from 27 species grown in monoculture showed that species differed in a trait, R*, which is the level to which each species reduced the concentration of soil nitrate, the limiting soil nutrient and which is predicted to be inversely associated with competitive ability for nitrogen (N). In these N-limited habitats, species abundance ranks correlated with their predicted competitive ranks: low R* species, on average dominated. These correlations were significantly different than expected for neutral theory, which assumes the exchangeability of species traits. Additionally, we found that changes in relative abundance after environmental change (N-addition or disturbance) were not neutral but also were significantly associated with R*.}, keywords = {LTER-KNZ}, doi = {10.1111/j.1461-0248.2005.00836.x}, author = {Harpole, W.S. and Tilman, D.} }