Agriculture, Ecosystems and Environment 104 (2004) 475–481 Vegetation change associated with land-use in tropical dry forest areas of Western Mexico Ana Burgos ∗ , J. Manuel Maass Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México (UNAM), Campus Morelia, Apartado Postal 27-3 (Santa Maria), Morelia, Michoacan CP 58089, Mexico Received 5 February 2003; received in revised form 13 January 2004; accepted 20 January 2004 Abstract Patterns of vegetation changes associated with land-use and successional pathways in areas occupied by tropical dry forest in Western Mexico were described. A diagram of vegetation states and transitions (events that promote the change) was constructed using Petri nets, a tool for graphic and mathematical modelling. This conceptual model was verified by analysing the perception of 28 settlers, using an environmental narrative method. Three main pathways of vegetation changes associated with land-use were detected: (i) forest replaced by agriculture in flatlands, (ii) pasture established on slopes, and (iii) wood extraction carried out without slash-and-burn on hill crests. If cultivated areas in flatlands and pasture fields on slopes are not continuously maintained by farmers, thorny vegetation develops within one to 3 years. If left untouched, this secondary vegetation becomes a low forest dominated by Acacia and Mimosa sp. persisting for at least 20 years. © 2004 Elsevier B.V. All rights reserved. Keywords: Agro-landscape; Conceptual model; Petri Nets; Successional pathways; Chamela Region 1. Introduction Identification and description of patterns of vege- tation change associated with anthropogenic actions permit the recognition of post-disturbance succes- sional pathways and management preferences of local people. Vegetation change models are frequently used as conceptual constructions to describe and explain successional pathways that result from natural and anthropogenic stressors (Gentile et al., 2001). They allow to predict the course of particular successions by specifying the relationships between mechanisms ∗ Corresponding author. Tel.: +52-443-322-2777x42506; fax: +52-443-322-2719. E-mail address: aburgos@oikos.unam.mx (A. Burgos). and pathways, to explore alternative pathways into the future and to conduct experiments that test our understanding of key processes (Pickett et al., 1987; Lambin et al., 2000). One of the most extensive and important tropical vegetation types in Mexico and Central America is the tropical dry forest (Murphy and Lugo, 1995), distributed along the Pacific Coast from the Tropic of Cancer, Mexico (28 ◦ N) to northern Costa Rica (10 ◦ N) (Pennington et al., 2000). Tropical dry for- est conversion to pasture and agriculture land has been a common practice in the region and intact forest is very scarce (Maass, 1995). Only 27% of the original tropical dry forest remains undisturbed in Mexico, the other 73% having some disturbance from an alteration or degradation up to a total 0167-8809/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.agee.2004.01.038