Desika Moodley1 and Petr Pyšek1,2
1The Czech Academy of Sciences, Institute of Botany, Department of Invasion Ecology, CZ-252 43, Průhonice, Czech Republic
2Department of Ecology, Faculty of Science, Charles University, Viničná 7, CZ-128 44 Prague, Czech Republic
Plant invasions are increasingly attracting the interest of ecologists because of their worldwide environmental impacts and huge economic costs. Factors that drive plant invasions have recently become well understood, however, surprisingly little is known about the processes and mechanisms of invasions into undisturbed ecosystems harboured in protected areas (PAs). Estimating management costs requires an understanding of the relative invasion across PAs, however, the last global overview is from the 1980s and available data on species distributions is often incomplete and regionally poor. To close the knowledge gap on the distribution of alien plants in protected areas globally, as well as examine how plant invasions differ between PA landscapes and those operating in non-protected landscapes, we aim to (i) build a new global inventory of naturalized and invasive plant species in PAs, (ii) measure the level to which PAs suffer from invasions, and (3) investigate the relationship between the overall level of invasion in a region and in PAs located within that region. A list of PAs was extracted from the World Database on Protected Areas and invasion records were collated using literature, local databases and unpublished accounts. The Global Naturalized Alien Flora (GloNAF) database was used to measure the overall level of invasion in a region and its effect on PAs. We tested the hypotheses that a large proportion of PAs will contain alien species, particularly PAs that occupy a large area with heterogeneous habitats; and that a higher number of naturalized and invasive alien plants will be recorded in PAs located within regions that comprise a higher alien plant richness. While inventories of invasive alien plants will never be complete or flawless, it is a valuable baseline tool for both invasion science and management.