title: Classification and ordination of main plant communities along an altitudinal gradient in the arid and temperate climates of northeastern Mexico.
abstract: Quantitative data on the ecology of the main plant communities along an altitudinal gradient in northeastern Mexico were obtained with the aim of identifying the most important environmental variables that affect plant distribution and composition. The main threats to these communities were also investigated. Importance value index (IVi) of the 39 most important species and 16 environmental variables were recorded at 35 altitudinal gradients each spaced at intervals of at least 100-m altitude. Classification and ordination of vegetation showed six well-differentiated but overlapping plant communities: alpine meadow, cold conifer forest, mesic mixed forest, xeric scrub, Tamaulipan piedmont scrub, and halophytic grassland. Altitude, minimum and average temperatures, and organic matter content are the main variables affecting the plant distribution in northeastern Mexico. Urban growth, mechanized agriculture, and changes in land use are the main threats in the short and medium term to plant communities in this area. Climate change also seems to be having an impact at present or in the near future as shown by the presence of exotic shrubs from warmer areas in mesic and temperate areas inhabited by oak and oak-pine forest.
authors.affiliation: Facultad de Ciencias Forestales, Universidad Autónoma de Nuevo León, Km 145 Carretera Nacional Linares-Cd. Victoria, A.P. 41, Linares, Nuevo León, 67700, Mexico. aeduardoestradac@prodigy.net.mx.
authors.forename: Eduardo Estrada
authors.initials: EE
authors.lastname: Castillón
authors.affiliation: Departamento de Botánica, Ecología y Fisiología Vegetal, Facultad de Ciencias, Universidad de La Laguna, E-38206, Islas, Canarias, Spain. jarevalo@ull.edu.es.
authors.forename: José Ramón
authors.initials: JR
authors.lastname: Arévalo
authors.affiliation: Departamento de Botánica, Universidad Autónoma Agraria Antonio Narro, Blvd. Antonio Narro, s/n, Buenavista, Saltillo, Coahuila, Mexico.
authors.forename: José Ángel Villarreal
authors.initials: JÁ
authors.lastname: Quintanilla
authors.affiliation: Facultad de Ciencias Forestales, Universidad Autónoma de Nuevo León, Km 145 Carretera Nacional Linares-Cd. Victoria, A.P. 41, Linares, Nuevo León, 67700, Mexico.
authors.forename: María Magdalena Salinas
authors.initials: MM
authors.lastname: Rodríguez
authors.affiliation: Departamento de Botánica, Universidad Autónoma Agraria Antonio Narro, Blvd. Antonio Narro, s/n, Buenavista, Saltillo, Coahuila, Mexico.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Encina-Domínguez
authors.affiliation: Facultad de Ciencias Forestales, Universidad Autónoma de Nuevo León, Km 145 Carretera Nacional Linares-Cd. Victoria, A.P. 41, Linares, Nuevo León, 67700, Mexico.
authors.forename: Humberto González
authors.initials: HG
authors.lastname: Rodríguez
authors.affiliation: Facultad de Ciencias Forestales, Universidad Autónoma de Nuevo León, Km 145 Carretera Nacional Linares-Cd. Victoria, A.P. 41, Linares, Nuevo León, 67700, Mexico.
authors.forename: César Martín Cantú
authors.initials: CM
authors.lastname: Ayala
mesh_terms: D000531:Altitude; D002980:Climate; D057231:Climate Change; D017753:Ecosystem; D008800:Mexico; D018521:Plant Physiological Phenomena; D010944:Plants / Q000145:classification*
keywords: Conservation; Environmental variables; Multivariate analysis; Northeastern Mexico; Plant communities