TY - JOUR T1 - Grassland productivity limited by multiple nutrients JF - Nature Plants Y1 - 2015 A1 - Fay, P.A. A1 - Prober, S.M. A1 - Harpole, W.S. A1 - Knops, J.M.H. A1 - J.D. Bakker A1 - E.T. Borer A1 - Lind, E.M. A1 - MacDougall, A.S. A1 - Seabloom, E.W. A1 - Wragg, P.D. A1 - P. Adler A1 - D.M. Blumenthal A1 - Buckley, Y.M. A1 - Chu, C. A1 - Cleland, E.E. A1 - Scott. L. Collins A1 - Davies, K.F. A1 - G. Du A1 - Feng, X. A1 - Firn, J. A1 - Gruner, D.S. A1 - Hagenah, N. A1 - Hautier, Y. A1 - Heckman, R.W. A1 - Jin, V.L. A1 - Kirkman, K.P. A1 - Klein, J. A1 - L. Ladwig A1 - Li, Q. A1 - McCulley, R.L. A1 - Melbourne, B.A. A1 - Mitchell, C.E. A1 - Joslin L. Moore A1 - J.W. Morgan A1 - A. Risch A1 - schütz, M. A1 - Stevens, C.J. A1 - Wedin, D.A. A1 - Yang, L.H. AB -

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.

VL - 1 UR - https://www.nature.com/articles/nplants201580 IS - 7 ER - TY - JOUR T1 - Plant species’ origin predicts dominance and response to nutrient enrichment and herbivores in global grasslands JF - Nature Communications Y1 - 2015 A1 - Seabloom, E.W. A1 - E.T. Borer A1 - Buckley, Y. A1 - Cleland, E.E. A1 - Davies, K.F. A1 - Firn, J. A1 - Harpole, W.S. A1 - Hautier, Y. A1 - Lind, E. A1 - MacDougall, A.S. A1 - Orrock, J.L. A1 - Prober, S.M. A1 - P. Adler A1 - Anderson, T.M. A1 - J.D. Bakker A1 - L.A. Biederman A1 - D.M. Blumenthal A1 - C.S. Brown A1 - Brudvig, L.A. A1 - Cadotte, M. A1 - Chu, C. A1 - Cottingham, K.L. A1 - Crawley, M.J. A1 - Damschen, E.I. A1 - D’Antonio, C.M. A1 - CeCrappeo, N.M. A1 - G. Du A1 - Fay, P.A. A1 - Frater, P. A1 - Gruner, D.S. A1 - Hagenah, N. A1 - Hector, A. A1 - Hillebrand, H. A1 - Hofmockel, K.S. A1 - Humphries, H.C. A1 - Jin, V.L. A1 - Kay, A.D. A1 - Kirkman, K.P. A1 - Klein, J.A. A1 - Knops, J.M.H. A1 - Kimberly J. La Pierre A1 - L. Ladwig A1 - Lambrinos, J.G. A1 - Li, Q. A1 - Li, W. A1 - Marushia, R. KW - Biological sciences KW - ecology KW - Plant sciences AB -

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.

VL - 6 UR - https://www.nature.com/articles/ncomms8710 ER - TY - JOUR T1 - Predicting invasion in grassland ecosystems: is exotic dominance the real embarrassment of richness? JF - Global Change Biology Y1 - 2013 A1 - Seabloom, E.W. A1 - E.T. Borer A1 - Buckley, Y. A1 - Cleland, E.E. A1 - Davies, K. A1 - Firn, J. A1 - Harpole, W.S. A1 - Hautier, Y. A1 - Lind, E. A1 - MacDougall, A. A1 - Orrock, J.L. A1 - Prober, S.M. A1 - P. Adler A1 - J. Alberti A1 - Anderson, M.T. A1 - J.D. Bakker A1 - L.A. Biederman A1 - D.M. Blumenthal A1 - C.S. Brown A1 - Brudvig, L.A. A1 - Caldeira, M. A1 - Chu, C. A1 - Crawley, M.J. A1 - Daleo, P. A1 - Damschen, E.I. A1 - D'Antonio, C.M. A1 - DeCrappeo, N.M. A1 - Dickman, C.R. A1 - G. Du A1 - Fay, P.A. A1 - Frater, P. A1 - Gruner, D.S. A1 - Hagenah, N. A1 - Hector, A. A1 - Helm, A. A1 - Hillebrand, H. A1 - Hofmockel, K.S. A1 - Humphries, H.C. A1 - Iribarne, O. A1 - Jin, V.L. A1 - Kay, A. A1 - Kirkman, K.P. A1 - Klein, J.A. A1 - Knops, J.M.H. A1 - Kimberly J. La Pierre A1 - L. Ladwig A1 - Lambrinos, J.G. A1 - Leakey, A.D.B. A1 - Li, Q. A1 - Li, W. A1 - McCulley, R. A1 - Melbourne, B. A1 - Mitchell, C.E. A1 - Joslin L. Moore A1 - J.W. Morgan A1 - Mortensen, B. A1 - O'Halloran, L.R. A1 - Pärtel, M. A1 - Pascual, J A1 - Pyke, D.A. A1 - A. Risch A1 - Salguero-Gomez, R. A1 - Sankaran, M. A1 - Schuetz, M. A1 - Simonsen, A. A1 - M.D. Smith A1 - Stevens, C. A1 - Sullivan, L. A1 - Wardle, G.M. A1 - Wolkovich, E.M. A1 - Wragg, P.D. A1 - Wright, J. A1 - Yang, L. AB -

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' relative abundance will more rapidly advance our understanding of invasions.

VL - 19 UR - https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12370 IS - 12 ER -