Drivers of Solidago species invasion in Central Europe---Case study in the landscape of the Carpathian Mountains and their foreground

Abstract

Abstract Aim: The invasion process is a complex, context-dependent\nphenomenon; nevertheless, it can be described using the PAB framework.\nThis framework encompasses the joint effect of propagule pressure (P),\nabiotic characteristics of the environment (A), and biotic\ncharacteristics of both the invader and recipient vegetation (B). We\nanalyzed the effectiveness of proxies of PAB factors to explain the\nspatial pattern of Solidago canadensis and S. gigantea invasion using\ninvasive species distribution models. Location: Carpathian Mountains and\ntheir foreground, Central Europe. Methods: The data on species presence\nor absence were from an atlas of neophyte distribution based on a 2 × 2\nkm grid, covering approximately 31,200 km2 (7752 grid cells). Proxies of\nPAB factors, along with data on historical distribution of invaders were\nused as explanatory variables in Boosted Regression Trees models to\nexplain the distribution of invasive Solidago. The areas with\npotentially lower sampling effort were excluded from analysis based on a\ntarget species approach. Results: Proxies of the PAB factors helped to\nexplain the distribution of both S. canadensis and S. gigantea.\nDistributions of both species were limited climatically because a\nmountain climate is not conducive to their growth; however, the S.\ncanadensis distribution pattern was correlated with proxies of human\npressure, whereas S. gigantea distribution was connected with\nenvironmental characteristics. The varied responses of species with\nregard to distance from their historical distribution sites indicated\ndifferences in their invasion drivers. Main conclusions: Proxies of PAB\nare helpful in the choice of explanatory variables as well as the\necological interpretation of species distribution models. The results\nunderline that human activity can cause variation in the invasion of\necologically similar species.