BIODIVERSITY RESEARCH Space matters when defining effective management for invasive plants Eliane S. Meier 1 *, Stefan Dullinger 2,3 , Niklaus E. Zimmermann 4 , Daniel Baumgartner 5 , Andreas Gattringer 2 and Karl H€ ulber 2,3 1 Agroscope, Institute for Sustainability Sciences ISS, Reckenholzstrasse 191, CH- 8046 Z€ urich, Switzerland, 2 Vienna Institute for Nature Conservation & Analyses, Giessergasse 6/7, A-1030 Vienna, Austria, 3 Department of Conservation Biology, Vegetation and Landscape Ecology, Faculty Centre of Biodiversity, University of Vienna, Rennweg 14, A-1030 Vienna, Austria, 4 Dynamic Macroecology Group, Landscape Dynamics Unit, Swiss Federal Research Institute WSL, Zuercherstrasse 111, CH-8903 Birmensdorf, Switzerland, 5 Economics and Social Sciences Group, Regional Economics and Development Unit, Swiss Federal Research Institute WSL, Zuercherstrasse 111, CH-8903 Birmensdorf, Switzerland *Correspondence: Eliane S. Meier, Agroscope, Institute for Sustainability Sciences ISS, Reckenholzstrasse 191, CH-8046 Z€ urich, Switzerland. E-mail: meier.eliane@gmail.com ABSTRACT Aim Invasive alien species are a threat to biodiversity and can harm resident plants, animals, humans and infrastructure. To reduce deleterious effects, effec- tive management planning for invasive plants is required. Currently, the effec- tiveness of management is primarily optimized locally through eradication of individual populations. By contrast, spatial prioritization of control activities at the landscape level has received less attention, despite its potential to improve management planning in complex landscapes, especially under budget constraints. Location North-eastern Switzerland, Europe. Methods We used a dynamic simulation model to evaluate the effectiveness of spatially designed management planning for controlling the expansion of three invasive alien plants (IAPs; Heracleum mantegazzianum, Impatiens glandulifera and Reynoutria japonica) across a heterogeneous landscape in North-eastern Switzerland. The model predicted the spread of IAPs from their current distri- bution under constraints of 361 control options differing in local intensity, frequency, duration, area and spatial prioritization of eradication measures. Results Our results demonstrate that IAP-control actions under a restricted budget are more effective if control actions are spatially prioritized. Most effec- tive spatial treatments generally prioritized small populations in the case of the annual species and large populations in the case of the perennial species. Fur- ther, applying intensive control at early stages generally increased effectiveness of control. Main conclusions For IAP-management planning, our findings suggest that control should be applied early when IAPs start spreading, to maximize success or minimize costs. Further, spatial prioritization schemes are particularly useful under limited financial means for IAP-management. Finally, our modelling approach may serve as a proof of concept to evaluate the effectiveness of control actions of various IAPs in complex landscapes. Keywords Alien species, biological invasions, complex landscapes, Heracleum mante- gazzianum, Impatiens glandulifera, population growth, Reynoutria japonica, riparian habitats, spatial spread, species distribution model. INTRODUCTION Alien invasive species reduce ecosystem functions and ser- vices by out-competing native species, harming the health of humans and domestic animals, damaging infrastructure, providing feeding niches for other pests, altering nutrient cycling or changing fire and water regimes (Vil  a et al., 2011). Evaluating the efficiency of control actions to constrain bio- logical invasions is hence an important issue (e.g. Brabec & Py  sek, 2000; Shea et al., 2010). So far, most studies have DOI: 10.1111/ddi.12201 ª 2014 John Wiley & Sons Ltd http://wileyonlinelibrary.com/journal/ddi 1 Diversity and Distributions, (Diversity Distrib.) (2014) 1–15 A Journal of Conservation Biogeography Diversity and Distributions