Table E-l. Model and description (continued) 
Screening system. Daehler and Carino (2000) tested three systems for their ability to screen for invasive species in 
Hawaii: (1) The North American “decision tree,” (2) The South African “linear series of five modules,” and (3) The 
Australian “49 questions.” The North American and Australian screening systems had the best results for predicting 
invasive species in Hawaii, and both need only minor changes to be used in new areas. The authors recommend 
modifying the Australian screening systems for international use. 
Multiple competing models. Adams et al. (2003) use multiple competing models to test the association of invasive 
bullfrogs with non-native fish. Specifically, multiple competing models are used with field survey data to rank the 
most important factors on bull frog distribution and abundance. Data from field experiments were modeled using 
logistic regression. The authors found that non-native fish facilitate survival of bullfrog tadpoles. The authors 
recommend that users regard the fish as a “keystone invader” in ponds or lakes that were fishless. 
Neutral landscape models. With (2004) uses a neutral landscape model (NLM) to determine how landscape 
structures impact invasive species dispersal. NLMs are based on percolation theory, which examines flows through 
heterogeneous materials. The author finds that poor dispersers may spread more readily when the disturbance area 
is large or concentrated in space. Good dispersers may spread better with small and localized disturbance. The 
author recommends developing land management actions to control invasive species based on whether dispersal or 
demography affects spread more. 
Economic model. Perrings (2002) creates a model of biological invasions based on fixed parameters (invasion rate, 
restoration rate) and a variable control rate. The model demonstrates that the higher the control rate, the lower the 
proportion of space occupied by the invasive species. In cases where the system is not controllable or observable, 
the author recommends control choices that reflect the precautionary approach. 
Review of approaches to assessing invasive plants. Rejmanek (2000) provides a review of approaches: (1) 
stochastic; (2) empirical taxon-specific; (3) biological characterization; (4) habitat compatibility; and (5) 
experimental, which can be used to address three objectives: (1) prevention/exclusion of invasive species; (2) early 
detection and rapid response; and (3) control/containment/eradication. Descriptions of each approach, examples of 
its use, and how it can be used with the other approaches are included. The author concludes that the most robust 
predictions will be made using more than one approach at the same time, and he recommends that closer attention be 
given to habitat-specific predictions._ 
*Model considers climate variables and/or climate change factors. 
E-l 
