Catalogue of neophytes in Belgium (1800-2005)
Verloove, F. (2006). Catalogue of neophytes in Belgium (1800-2005). Scripta Botanica Belgica, 39. National Botanic Garden of Belgium: Meise. ISBN 90-72619-71-4. 89 pp. Part of: Scripta Botanica Belgica. National Botanic Garden of Belgium/Nationale Plantentuin van België = Jardin Botanique National de Belgique: Meise. ISSN 0779-2387, more |  |
| Abstract | A catalogue of Belgian neophytes has been compiled for the first time on the basis of a thorough and critical revision of the main public and some smaller but nevertheless relevant Belgian herbaria. All non-native vascular plant species, recorded in Belgium since 1800, are included regardless of degree of naturalization (including occasional garden escapes and casual aliens as well as invasive taxa). Taxa that were already naturalized in Belgium in pre-Columbian times, are excluded. The following data are provided for each taxon: scientific name, synonym, family, mode of introduction (accidental/deliberate), date of the first collection (except if earlier reliable records are available), date of the most recent record, native geographic area, presence or absence in Flanders, Brussels Capital Region and Wallonia (the three main political units), degree of naturalization and (main) vector(s) of introduction. 1,969 taxa are included. More than 20 % appears to be “new” for the Belgian flora. On the other hand, at least 30 taxa were erroneously included in the presentday Flora and need to be omitted in a future edition. Assessing the exact status of many taxa of the “Belgian” flora proved to be problematic. On the one hand, the distinction between native and non-native turned out to be often critical (for instance: interpretation of natural range extensions). On the other hand, assessing archaeophytic or neophytic status for (presumed) non-native taxa turned out not to be always obvious. Similarly, the assessment of the degree of naturalization (measurement of a taxon’s success) was not always straightforward. In practice, and despite numerous recent international papers on this subject, the distinction between “naturalized” and “invasive” regularly proved to be arbitrary. The Belgian non-native vascular flora is remarkably wealthy and diverse: no less than 139 families are represented but most families count for only (very) few taxa. Poaceae and Asteraceae are the largest families and represent more than a quarter of the total number of alien taxa in Belgium. A huge number of the aliens were initially introduced deliberately, primarily for horticultural reasons. Among the naturalized and/or invasive taxa the proportion of deliberate introductions is even more important (ca. 60 %). Introductions from Europe and temperate Asia are most common. To a lesser extent, Africa (especially North-Africa) and America (especially North-America) are also important sources. As expected, the number of introductions from Australia, tropical Asia and the (sub-) tropics as a whole is limited. A large majority, at least 75 %, of the introductions remains strictly casual. At most 20 % is able to become naturalized, locally as well as widespread. At present, the number of invasive taxa (spreading fast in more or less natural habitats) and noxious taxa (harmful in terms of biodiversity, public health or for economic reasons) is limited. Currently, the main vector for plant introductions appears to be horticulture (garden escapes). Until the 1960’s woolimportation was chiefly responsible for the occurrence of accidental aliens. Nowadays, accidental aliens are usually brought in with cereals and grains. The number of new introductions has much increased in the course of the past decades. Similarly, the number of newly naturalized taxa has increased. |
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