Cultivar genotype, application and endophyte history affects community impact of Schedonorus arundinaceus.
Cultivars of several cool-season grasses used in forage and turf applications are developed to contain low (E-) or high (E+) seed fungal endophyte presence, and these characteristics may influence their competitive ability and effects on communities. We established a long-term field experiment to test the predictions that Schedonorus arundinaceus (SA) tall fescue forage cultivars differ in their effects on communities from turf cultivars and that E+ cultivars differ in their effects on communities from E- cultivars. Two of the three E+ turf cultivars were low endophyte, and turf cultivars were therefore defined as 'E+ history' and 'E- history'. Forage (E-) plots contained more SA than turf (E- history) plots and differed in community structure and function from turf (E- history) plots. Cultivar identity also influenced community structure and function in pairwise comparisons between forage (E-) and turf (E- history) plots. Within the forage cultivars, E+ plots contained more SA and were marginally less dominated by other grasses than E- plots, but these differences were not consistent in comparisons between specific E+ and E- forage cultivars. Moreover, E+ and E- forage plots were similar in other aspects of community structure and function, indicating that a cultivar's endophyte status does not consistently determine its effects. Despite low endophyte presence in two of three cultivars, E+ history turf plots differed in measures of composition, structure and nutrient cycling from E- history turf plots, indicating that there are genetic differences between E+ and E- cultivars which can influence their effects on communities. Synthesis and applications. Schedonorus arundinaceus cultivars vary in their competitive ability and effects on communities, and this variation may be explained by the application for which the cultivars were developed, their endophyte status and genetic differences among cultivars within application categories. We recommend preferentially selecting cultivars developed for turf applications and cultivars with low seed endophyte presence to minimize negative effects of seeding a non-native grass on communities. However, final selections should be based on common trial performances because genetic differences between cultivars will affect their performance independently of their application category and endophyte status.