Bentgrass Distribution Surveys and Habitat Suitability Maps Support Ecological Risk Assessment in Cultural Landscapes

Abstract

The bentgrasses comprise an adaptable group of grasses that include introduced species, cultivated turfgrasses, and native plants in North America. Their distribution in cultural landscapes has not been documented, and this gap in knowledge has limited the development of predictive ecological risk assessments for creeping bentgrass engineered for herbicide resistance. In this study, bentgrass distribution and abundance were surveyed in 289 plots in an 8.5 km2 site surrounding a golf course in the northeastern United States. Four introduced species and two native bentgrasses were identified in seminatural and managed plant communities. Across the study site, 77% of the plots containing creeping bentgrass also had invasive plants. Bentgrasses co-occurred with critical habitat for threatened or endangered animals. Multivariate logistic regression analysis showed that bentgrasses were positively correlated with herbaceous plant cover and mowing, but negatively correlated with tree canopy cover, shrub cover, poorly drained soils, and leaf litter. The most influential ecological factors were tree canopy cover and soil moisture. Geospatial information about these two ecological factors was combined with mathematical models to generate two habitat suitability maps. The favorable environments map (FEM) showed that highly suitable bentgrass habitat covered 36% of the study site and included common features such as home lawns and railroad right-of-ways. Our results suggest that release of herbicide-resistant creeping bentgrass in this cultural landscape could potentially result in pollen-mediated gene flow, interspecific hybridization, environmental hazards, and herbicide selection pressure in some areas. Habitat suitability maps could be critical tools for predictive ecological risk assessments, monitoring projects, and management of herbicide-resistant bentgrasses.