03210nas a2200181   4500008004100000245014900041210006900190300001500259490000800274520256100282100001502843700002102858700001702879700001502896700001702911700001902928856008102947       2013                        eng d00aLinking abundances of the dung fungus Sporormiella to the density of bison: implications for assessing grazing by megaherbivores in paleorecords0 aLinking abundances of the dung fungus Sporormiella to the densit  a1125 -11360 v1013 a<p>Megaherbivores likely had important influences on past vegetation dynamics, just as they do in modern ecosystems. The exact nature of megaherbivores&#39; role can be studied using a relatively new suite of palaeoecological techniques, including the quantification of fossil spores from Sporormiella and other coprophilous fungi as indicators of megafaunal biomass in sediment records. However, a quantitative linkage of spore abundance with megaherbivore biomass or grazing intensity has been lacking. Konza Prairie Biological Station (Kansas, USA), located in the midcontinent of North America, contains native tallgrass prairie grazed by a herd of bison (Bison bison) in a 1000-ha enclosure, providing an excellent opportunity to test the effects of megaherbivores on grassland community composition and their potential signature in the palynological record. We collected pollen and spores during 2009 and 2010 from a network of 28 modified Tauber traps. The precise locations of the bison herd were recorded using GPS collars; we calculated bison grazing intensity (kg m&minus;2 year&minus;1) to high spatial precision within concentric circles around each trap (radii from 25 to 500 m). Both relative (per cent) and absolute (concentration) abundances of Sporormiella were significantly higher in traps inside the enclosure and were positively correlated with bison grazing intensity. The cut-off for distinguishing between bison-grazed and ungrazed traps was determined to be 2.8% Sporormiella of the total pollen and spore sum, consistent with previous palaeoecological reconstructions. The relationship between Sporormiella abundances and available grazing area around each trap was strongest at short radii (25&ndash;100 m), suggesting that spores do not disperse far from their source. Sporormiella should thus be considered a local-scale indicator of megaherbivore presence. Traps in the grazed area had significantly higher percentages of Ambrosia and lower percentages of Poaceae pollen than traps from ungrazed areas. This suggests that the pollen record has the potential to detect the ecological effects of bison grazing on grassland community composition. Synthesis. This study refines the use of Sporormiella as a proxy for local megaherbivore presence, especially in grassland systems. Multiproxy Sporormiella and pollen analyses may help elucidate the past drivers of grassland dynamics, including the possible role of bison in mediating grass&ndash;forb interactions during the variable moisture regimes of the last 12,000 years.</p>1 aGill, J.L.1 aMcLauchlan, K.K.1 aSkibbe, A.M.1 aGoring, S.1 aZirbel, C.R.1 aWilliams, J.W.  uhttps://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.1213002695nas a2200157   4500008004100000245012600041210006900167300001500236490000700251520208300258100002002341700001902361700001602380700001702396856012402413       2004                        eng d00aScale dependence in the relationship between species richness and productivity: the role of spatial and temporal turnover0 aScale dependence in the relationship between species richness an  a2701 -27080 v853 aRecent research in aquatic systems suggests that productivity–richness relationships change with spatial scale and that species turnover (i.e., spatial and temporal variation in species composition) plays an important role in generating this scale dependence. The generality of such scale dependence and the effects of variation in temporal scale remain unknown. We examined the extent to which the richness–productivity relationship in terrestrial plant communities depends on spatial or temporal scale and evaluated how spatial and temporal turnover (i.e., species turnover in space and time) generates scale dependence in these relationships using data from two Long-Term Ecological Research (LTER) sites (Jornada and Konza). We found a weak hump-shaped relationship (Jornada) and no relationship (Konza) between richness and productivity at the smallest focal scale (1 m2 at Jornada and 50 m2 at Konza) at each site, but strong hump-shaped relationships at the largest focal scale (49 m2 at Jornada and 200 m2 at Konza) for each site. Relationships between spatial turnover and productivity at each site mirrored the productivity–richness relationships that emerged at the larger spatial scale (i.e., a significant hump-shaped pattern). In contrast, temporal turnover was unrelated to productivity, and hence increasing temporal scale did not appreciably change the form of the productivity–richness relationship. Our study suggests that the way in which productivity–richness relationships change with spatial or temporal scale depends on the form and strength of the underlying relationship between species turnover and productivity. Moreover, we contend that a dominant effect of increasing productivity is the generation of dissimilarity in species composition among localities that comprise a region, rather than increasing the number of species that occur within local communities. Thus, understanding the mechanisms that cause species turnover to vary with productivity is critical to understanding scale dependence in richness–productivity relationships.1 aChalcraft, D.R.1 aWilliams, J.W.1 aSmith, M.D.1 aWhiles, M.R.  uhttp://knz.lternet.edu/content/scale-dependence-relationship-between-species-richness-and-productivity-role-spatial-and