Where are the Alien Species? Predictions of Global Plant Species Invasions under Current Environmental Conditions and the Human Footprint

Abstract

Species invasion is a significant concern because of its substantial effect on native ecosystems. A number of species-specific invasion predictions that correspond to environmental conditions are available, but literature predicting global species invasion that corresponds to environmental conditions and human activity is scarce. In this study, the potential geographic ranges of 308 alien plant species were predicted under current environmental conditions and human activities. Environmental conditions were delineated by bioclimatic (mean annual temperature, mean annual precipitation, mean temperature of wettest quarter, and precipitation of driest quarter) and topographic variables (annual solar radiation and topographic wetness index). Human activity was delineated by the human footprint, which is a raster data layer created from nine global data layers that describe human population pressure, land use and infrastructure, and human access. The potential distribution of the target species was predicted using the different types of models. By searching the correlated literature, we identified and excluded the native geographic range of the studied species in the predicted geographic range to obtain the exclusive invasive range. Results demonstrated that the invasion hotspots included the southern part of North America, Southern and Western Europe, the south coast of Asia, coastal regions of Australia and New Zealand, the coast of West Africa, the Ivory Coast of Africa, and the southern part of Brazil. In addition, the land areas of the low-(proper for less than 50 alien species), moderate-(51-100 aliens), and high-risk regions (more than 100 aliens) are 213.23, 18.15, and 2.50 million km 2 , respectively. All variables (bioclimatic and topographic variables and human footprint) were positively correlated with increasing richness of alien species. The highest correlation coefficient was obtained for the human footprint.

Predicting the potential distribution area of Solidago ×niederederi (Asteraceae)

“…From the conservation point of view, predicting geographical distribution of such hybrids is a first step in controlling their further spreading. Various modeling methods (heavily based on climatic data) have been used to predict distribution areas of naturalized or invasive plant species (e.g., Pattison and Mack, 2008;Qin et al, 2015;Wang and Xu, 2016). Unfortunately, there is a lack of study on modeling potential geographical distribution for hybrids between alien and native plant species that have the ability to produce their own offspring and become established.…”

A framework for mapping cumulative threats and its application to Canada

“…Only four studies reported pressures through to impacts (Appendix 6.1). In these studies, impacts were measured directly as biodiversity loss, species abundance change or range changes of species (Leu et al 2008;Whitehead et al 2016;Wang & Zhonglin Xu 2016). The human footprint measuring resource use identified the impacts of emissions, water use, land occupation, eutrophication and terrestrial acidification, from the included pressures by using a lifecycle assessment tool of the resource use (Verones et al 2017).…”