TY - JOUR T1 - Global diversity of drought tolerance and grassland climate-change resilience JF - Nature Climate Change Y1 - 2013 A1 - Craine, J.M. A1 - Ocheltree, T.W. A1 - Jesse B. Nippert A1 - Towne, E.G. A1 - Skibbe, A.M. A1 - Kembel, S.W. A1 - Fargione, J.E. KW - Climate-change ecology KW - Drought KW - Grassland ecology AB -

Drought reduces plant productivity, induces widespread plant mortality and limits the geographic distribution of plant species1, 2, 3, 4, 5, 6, 7. As climates warm and precipitation patterns shift in the future8, 9, understanding the distribution of the diversity of plant drought tolerance is central to predicting future ecosystem function and resilience to climate change10, 11, 12. These questions are especially pressing for the world’s 11,000 grass species13, which dominate a large fraction of the terrestrial biosphere14, yet are poorly characterized with respect to responses to drought. Here, we show that physiological drought tolerance, which varied tenfold among 426 grass species, is well distributed both climatically and phylogenetically, suggesting most native grasslands are likely to contain a high diversity of drought tolerance. Consequently, local species may help maintain ecosystem functioning in response to changing drought regimes without requiring long-distance migrations of grass species. Furthermore, physiologically drought-tolerant species had higher rates of water and carbon dioxide exchange than intolerant species, indicating that severe droughts may generate legacies for ecosystem functioning. In all, our findings suggest that diverse grasslands throughout the globe have the potential to be resilient to drought in the face of climate change through the local expansion of drought-tolerant species.

VL - 3 UR - https://www.nature.com/articles/nclimate1634 ER - TY - JOUR T1 - Incorporating clonal growth form clarifies the role of plant height in response to nitrogen addition JF - Oecologia Y1 - 2012 A1 - Gough, L. A1 - Gross, K.L. A1 - Cleland, E.E. A1 - Clark, C.M. A1 - Scott. L. Collins A1 - Fargione, J.E. A1 - Pennings, S.C. A1 - K.N. Suding KW - Clonal growth KW - Competition KW - grassland KW - Nitrogen addition KW - productivity AB -

Nutrient addition to grasslands consistently causes species richness declines and productivity increases. Competition, particularly for light, is often assumed to produce this result. Using a long-term dataset from North American herbaceous plant communities, we tested whether height and clonal growth form together predict responses to fertilization because neither trait alone predicted species loss in a previous analysis. Species with a tall-runner growth form commonly increased in relative abundance in response to added nitrogen, while short species and those with a tall-clumped clonal growth form often decreased. The ability to increase in size via vegetative spread across space, while simultaneously occupying the canopy, conferred competitive advantage, although typically only the abundance of a single species within each height-clonal growth form significantly responded to fertilization in each experiment. Classifying species on the basis of two traits (height and clonal growth form) increases our ability to predict species responses to fertilization compared to either trait alone in predominantly herbaceous plant communities.

VL - 169 UR - https://link.springer.com/article/10.1007%2Fs00442-012-2264-5 ER - TY - JOUR T1 - Patterns of trait convergence and divergence among native and exotic species in herbaceous plant communities are not modified by nitrogen enrichment JF - Journal of Ecology Y1 - 2011 A1 - Cleland, E.E. A1 - Clark, C.M. A1 - Scott. L. Collins A1 - Fargione, J.E. A1 - Gough, L. A1 - Gross, K.L. A1 - Pennings, S.C. A1 - K.N. Suding VL - 99 UR - https://www.jstor.org/stable/41333056?seq=1#page_scan_tab_contents ER - TY - JOUR T1 - Rank clocks and plant community dynamics JF - Ecology Y1 - 2008 A1 - Scott. L. Collins A1 - K.N. Suding A1 - Cleland, E.E. A1 - Batty, M. A1 - Pennings, S.C. A1 - Gross, K.L. A1 - Grace, J.S. A1 - Gough, L. A1 - Fargione, J.E. A1 - Clark, C.M. AB - Summarizing complex temporal dynamics in communities is difficult to achieve in a way that yields an intuitive picture of change. Rank clocks and rank abundance statistics provide a graphical and analytical framework for displaying and quantifying community dynamics. We used rank clocks, in which the rank order abundance for each species is plotted over time in temporal clockwise direction, to display temporal changes in species abundances and richness. We used mean rank shift and proportional species persistence to quantify changes in community structure in long-term data sets from fertilized and control plots in a late successional old field, frequently and infrequently burned tallgrass prairie, and Chihuahuan desert grassland and shrubland communities. Rank clocks showed that relatively constant species richness masks considerable temporal dynamics in relative species abundances. In the old field, fertilized plots initially experienced high mean rank shifts that stabilized rapidly below that of unfertilized plots. Rank shifts were higher in infrequently burned vs. annually burned tallgrass prairie and in desert grassland compared to shrubland vegetation. Proportional persistence showed that arid grasslands were more dynamic than mesic grasslands. We conclude that rank clocks and rank abundance statistics provide important insights into community dynamics that are often hidden by traditional univariate approaches. VL - 89 ER - TY - JOUR T1 - Species responses to nitrogen fertilization in herbaceous plant communities, and associated species traits JF - Ecology Y1 - 2008 A1 - Cleland, E.E. A1 - Clark, C.M. A1 - Scott. L. Collins A1 - Fargione, J.E. A1 - Gough, L. A1 - Gross, K.L. A1 - Pennings, S.C. A1 - W.D. Bowman A1 - Robertson, G.P. A1 - Simpson, J. A1 - Tilman, D. A1 - K.N. Suding AB -

This synthetic data set contains plant species relative abundance measures from 35 nitrogen (N) fertilization experiments conducted at 10 sites across North America. The data set encompasses the fertilization responses of 575 taxa from 1159 experimental plots. The methodology varied among experiments, in particular with regard to the type and amount of N added, plot size, species composition measure (biomass harvest, pin count, or percent cover), additional experimental manipulations, and experimental duration. At each site, each species has been classified according to a number of easily identified categorical functional traits, including life history, life form, the number of cotyledons, height relative to the canopy, potential for clonal growth, and nativity to the United States. Additional data are available for many sites, indicated by references to publications and web sites. Analyses of these data have shown that N enrichment significantly alters community composition in ways that are predictable on the basis of plant functional traits as well as environmental context. This data set could be used to answer a variety of questions about how plant community composition and structure respond to environmental changes.

VL - 89 UR - https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/07-1104.1 ER - TY - JOUR T1 - Environmental and plant community determinants ofspecies loss following nitrogen enrichment JF - Ecology Letters Y1 - 2007 A1 - Clark, C.M. A1 - Cleland, E.E. A1 - Scott. L. Collins A1 - Fargione, J.E. A1 - Gough, L. A1 - Pennings, S.C. A1 - K.N. Suding A1 - Grace, J.B. AB - Global energy use and food production have increased nitrogen inputs to ecosystems worldwide, impacting plant community diversity, composition, and function. Previous studies show considerable variation across terrestrial herbaceous ecosystems in the magnitude of species loss following nitrogen (N) enrichment. What controls this variation remains unknown. We present results from 23 N-addition experiments across North America, representing a range of climatic, soil and plant community properties, to determine conditions that lead to greater diversity decline. Species loss in these communities ranged from 0 to 65% of control richness. Using hierarchical structural equation modelling, we found greater species loss in communities with a lower soil cation exchange capacity, colder regional temperature, and larger production increase following N addition, independent of initial species richness, plant productivity, and the relative abundance of most plant functional groups. Our results indicate sensitivity to N addition is co-determined by environmental conditions and production responsiveness, which overwhelm the effects of initial community structure and composition. VL - 10 ER -