02351nas a2200241   4500008004100000022001400041245007700055210006900132300001400201490000800215520162000223653001701843653002301860653002201883653003001905100002901935700001901964700002301983700001702006700002702023700001602050856004302066       2017                        eng d  a0027-842400aDifferent clades and traits yield similar grassland functional responses0 aDifferent clades and traits yield similar grassland functional r  a705 - 7100 v1143 aPlant functional traits are viewed as key to predicting important ecosystem and community properties across resource gradients within and among biogeographic regions. Vegetation dynamics and ecosystem processes, such as aboveground net primary productivity (ANPP), are increasingly being modeled as a function of the quantitative traits of species, which are used as proxies for photosynthetic rates and nutrient and water-use efficiency. These approaches rely on an assumption that a certain trait value consistently confers a specific function or response under given environmental conditions. Here, we provide a critical test of this idea and evaluate whether the functional traits that drive the well-known relationship between precipitation and ANPP differ between systems with distinct biogeographic histories and species assemblages. Specifically, we compared grasslands spanning a broad precipitation gradient (∼200–1,000 mm/y) in North America and South Africa that differ in the relative representation and abundance of grass phylogenetic lineages. We found no significant difference between the regions in the positive relationship between annual precipitation and ANPP, yet the trait values underlying this relationship differed dramatically. Our results challenge the trait-based approach to predicting ecosystem function by demonstrating that different combinations of functional traits can act to maximize ANPP in a given environmental setting. Further, we show the importance of incorporating biogeographic and phylogenetic history in predicting community and ecosystem properties using traits. 10abiogeography10aEcosystem function10aFunctional traits10agrasslands. phylogenetics1 aForrestel, Elisabeth, J.1 aDonoghue, M.J.1 aEdwards, Erika, J.1 aJetz, Walter1 aToit, Justin, C. O. du1 aSmith, M.D.  uhttps://www.pnas.org/content/114/4/70502932nas a2200157   4500008004100000245016400041210006900205300001300274490000800287520232900295653001402624100002002638700001902658700001602677856008102693       2015                        eng d00aFunctional differences between dominant grasses drive divergent responses to large herbivore loss in mesic savanna grasslands of North America and South Africa0 aFunctional differences between dominant grasses drive divergent   a714 -7240 v1033 a<p>Grazing and fire are disturbances integral to the evolution and maintenance of savanna grasslands. Humans are altering or completely eliminating these disturbance regimes at a global scale, with important consequences for savanna ecosystem structure and function. It is unknown whether the alteration of these disturbance regimes will have similar effects on grass communities of savanna grasslands in different geographic regions that vary in their biogeographic and evolutionary histories, as well as in the diversity of extant grazers. Here, we examined the effects of large herbivore loss on different aspects of grass community structure &ndash; taxonomic, phylogenetic and functional &ndash; across a range of fire frequencies in C4-dominated mesic savanna grassland sites of North America (Konza Prairie Biological Station, Kansas, USA) and South Africa (Kruger National Park). The goal of the study was to determine whether the loss of large herbivores exerted a consistent effect on the grass communities of two physiognomically similar grasslands with different biogeographic and grazing histories. The removal of large herbivores resulted in divergent responses in the grass communities at Konza and Kruger that was consistent across fire treatments. At Konza, there was a rapid and significant response to grazing exclusion while the response was muted and transient at Kruger. Functional syndromes associated with grazing resistance were generally conserved across sites, and it was the functional strategies of the dominant species at each site that drove the divergent responses. Further, our study supports the hypothesis that grazing and aridity may be selective forces that act in parallel as those species that were grazing resistant also occupied drier niches. Synthesis. Our study demonstrates that savanna grassland communities with different biogeographic and grazing histories respond differently to the removal of large herbivores and that climate, fire and grazing are interactive forces in maintaining savanna grassland diversity and function. We show that the functional attributes of the dominant grasses, which are in part driven by the biogeographic and grazing history experienced, are the most relevant in predicting the response of savanna ecosystems to the loss of large herbivores.</p>10aphylogeny1 aForrestel, E.J.1 aDonoghue, M.J.1 aSmith, M.D.  uhttps://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.1237602006nas a2200145   4500008004100000245013900041210006900180300001500249490000800264520146600272100002001738700001901758700001601777856006701793       2014                        eng d00aConvergent phylogenetic and functional responses to altered fire regimes in mesic savanna grasslands of North America and South Africa0 aConvergent phylogenetic and functional responses to altered fire  a1000 -10110 v2033 a<p>The importance of fire in the creation and maintenance of mesic grassland communities is well recognized. Improved understanding of how grasses &ndash; the dominant clade in these important ecosystems &ndash; will respond to alterations in fire regimes is needed in the face of anthropogenically driven climate and land-use change. Here, we examined how grass communities shift in response to experimentally manipulated fire regimes at multiple levels of community diversity &ndash; taxonomic, phylogenetic and functional &ndash; in C4-dominanted mesic savanna grassland sites with similar structure and physiognomy, yet disparate biogeographic histories. We found that the grass communities were similar in their phylogenetic response and aspects of their functional response to high fire frequency. Both sites exhibited phylogenetic clustering of highly abundant species in annually burned plots, driven by species of the Andropogoneae, and a narrow range of functional strategies associated with rapid post-fire regeneration in a high-light, nitrogen-limited environment. By examining multiple facets of diversity in a comparative context, we identified convergent phylogenetic and functional responses to altered fire regimes in two mesic savanna grasslands. Our results highlight the importance of a common filtering process associated with fire that is consistent across grasslands of disparate biogeographic histories and taxonomic representation.</p>1 aForrestel, E.J.1 aDonoghue, M.J.1 aSmith, M.D.  uhttps://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.12846