Annemarie Breukers

Which factors affect the success or failure of eradication campaigns against alien species

Although issues related to the management of invasive alien species are receiving increasing attention, little is known about which factors affect the likelihood of success of management measures. We applied two data mining techniques, classification trees and boosted trees, to identify factors that relate to the success of management campaigns aimed at eradicating invasive alien invertebrates, plants and plant pathogens. We assembled a dataset of 173 different eradication campaigns against 94 species worldwide, about a half of which (50.9%) were successful. Eradications in man-made habitats, greenhouses in particular, were more likely to succeed than those in (semi-)natural habitats. In man-made habitats the probability of success was generally high in Australasia, while in Europe and the Americas it was higher for local infestations that are easier to deal with, and for international campaigns that are likely to profit from cross-border cooperation. In (semi-) natural habitats, eradication campaigns were more likely to succeed for plants introduced as an ornamental and escaped from cultivation prior to invasion. Averaging out all other factors in boosted trees, pathogens, bacteria and viruses were most, and fungi the least likely to be eradicated; for plants and invertebrates the probability was intermediate. Our analysis indicates that initiating the campaign before the extent of infestation reaches the critical threshold, starting to eradicate within the first four years since the problem has been noticed, paying special attention to species introduced by the cultivation pathway, and applying sanitary measures can substantially increase the probability of eradication success. Our investigations also revealed that information on socioeconomic factors, which are often considered to be crucial for eradication success, is rarely available, and thus their relative importance cannot be evaluated. Future campaigns should carefully document socioeconomic factors to enable tests of their importance.

Greenhouse vegetable production in The Netherlands and Switzerland: A grounded look at sector competitiveness

Purpose – The purpose of this paper is to develop a theory that is sufficiently adapted to sector competitiveness. The case of greenhouse vegetable production in The Netherlands and Switzerland is used to explain differences in sector competitiveness.Design/methodology/approach – Interviews focusing on the fields of spatial planning, labor, energy supply, and market organization were carried out with stakeholders and producers in both countries and evaluated by Grounded Theory.Findings – The work shows that the flexibility not only of producers, but also of the whole institutional framework in The Netherlands exceeds the flexibility on the Swiss side by far, which may be an important factor for explaining differences in competitiveness.Research limitations/implications – The result that it is a basic difference in flexibility and adaptability that determines sector competitiveness is valid for the vegetable sector. It should be examined whether similar patterns can be found in other sectors.Originality/va...

Extensive literature searches soil and growing media inventories : (RC/EFSA/PLH/2013/01-SC1)

In this project two inventories by means of extensive literature searches have been executed: Inventory 1 of all types of soil and growing media (if relevant components thereof) to be elaborated considering (i) the soil and growing medium imported as commodities (i.e. not in association with plants intended for planting), (ii) the soil and growing medium attached to plants for planting, and (iii) the soil and growing medium attached as a contaminant to imported goods (ranging from ware potatoes to agricultural machinery). Inventory 2, based on interceptions data and scientific and technical literature, of plant pests, plant diseases and weeds that can be associated with soil and growing medium (if relevant components thereof). Execution of Inventory 1 resulted in a list of 956 soils and growing media. Execution of Inventory 2 resulted in Excel tables for each taxonomic group separately in which the pests and diseases are linked to the soil and growing media. Additional information has been provided for processes applied to produce growing media and the impact on harmful organisms and private certification schemes applied in Europe to control the trade and use of growing media.