Drivers of Solidago species invasion in Central Europe---Case study in
the landscape of the Carpathian Mountains and their foreground
Abstract Aim: The invasion process is a complex, context-dependent
phenomenon; nevertheless, it can be described using the PAB framework.
This framework encompasses the joint effect of propagule pressure (P),
abiotic characteristics of the environment (A), and biotic
characteristics of both the invader and recipient vegetation (B). We
analyzed the effectiveness of proxies of PAB factors to explain the
spatial pattern of Solidago canadensis and S. gigantea invasion using
invasive species distribution models. Location: Carpathian Mountains and
their foreground, Central Europe. Methods: The data on species presence
or absence were from an atlas of neophyte distribution based on a 2 × 2
km grid, covering approximately 31,200 km2 (7752 grid cells). Proxies of
PAB factors, along with data on historical distribution of invaders were
used as explanatory variables in Boosted Regression Trees models to
explain the distribution of invasive Solidago. The areas with
potentially lower sampling effort were excluded from analysis based on a
target species approach. Results: Proxies of the PAB factors helped to
explain the distribution of both S. canadensis and S. gigantea.
Distributions of both species were limited climatically because a
mountain climate is not conducive to their growth; however, the S.
canadensis distribution pattern was correlated with proxies of human
pressure, whereas S. gigantea distribution was connected with
environmental characteristics. The varied responses of species with
regard to distance from their historical distribution sites indicated
differences in their invasion drivers. Main conclusions: Proxies of PAB
are helpful in the choice of explanatory variables as well as the
ecological interpretation of species distribution models. The results
underline that human activity can cause variation in the invasion of
ecologically similar species.