AN EXPERT-SYSTEM FOR SCREENING POTENTIALLY INVASIVE ALIEN PLANTS IN SOUTH-AFRICAN FYNBOS

Citation
Kc. Tucker et Dm. Richardson, AN EXPERT-SYSTEM FOR SCREENING POTENTIALLY INVASIVE ALIEN PLANTS IN SOUTH-AFRICAN FYNBOS, Journal of environmental management, 44(4), 1995, pp. 309-338
Citations number
60
Categorie Soggetti
Environmental Studies","Environmental Sciences
ISSN journal
03014797
Volume
44
Issue
4
Year of publication
1995
Pages
309 - 338
Database
ISI
SICI code
0301-4797(1995)44:4<309:AEFSPI>2.0.ZU;2-J
Abstract
The development and application of an expert system is described for s creening alien woody plants for their invasive potential in South Afri can fynbos. The system is proposed for use by potential introducers to demonstrate low invasive risk before importing woody alien species fo r cultivation. Rules for the system were derived from empirical eviden ce by quantifying invasion windows and barriers that have limited the set of widespread woody invaders (trees and shrubs) in fynbos to fewer than 20, out of several hundred introduced species. The system first compares broad-scale environmental conditions (climate and soil) betwe en the home environment of a species and fynbos. Features of the plant in its home environment (basic life history traits, population charac teristics, regeneration biology, habitat preferences) are then assesse d. Finally, an assessment is made of life history adaptations to the p revailing fire regime in fynbos (juvenile period, fire-survival capaci ty of adult plants, seed bank longevity). The reasoning is explicit an d the steps leading to a conclusion (high risk/low risk) can be retrac ed. Besides the obvious application in identifying species with a high risk of invading, the system has considerable potential for modelling , and for teaching the concepts of biological invasions. The rules pro vide an explicit conceptualization of invasion processes in fynbos and identify multiple paths to invasive success (not all of which have be en realized yet). The system can therefore be used in planning control operations (for optimal allocation of control effort to critical stag es in invasion), and for predicting the outcome of changes (e.g. in fi re frequency) on the dimensions of invasion windows, and for assessing what changes are needed to prevent or reduce the extent of invasion b y a given taxon. Application of the system is demonstrated on Pinus an d Banksia taxa and a selection of species from Californian chaparral. (C) 1995 Academic Press Limited