Bioclimates and vegetation along the Pacific basin of Northwestern Mexico

We describe relationships between the bioclimates and vegetation of the northwest of Mexico, including the Baja California peninsula and the stretch of the Pacific basin between the states of Sonora and Colima, a transition zone from the most arid deserts of North America to tropical rainforests. Links were inferred from temperature and rainfall data obtained from 453 weather stations that were used to construct climatograms, calculate several climate indices and describe main latitudinal and longitudinal trends, and from sampling the vegetation around these stations. Across this extensive area, spanning some 14° of both latitude and longitude as well as three zonobiomes and two zonoecotones, two macrobioclimates were identified, Mediterranean and Tropical, within which we were able to distinguish six bioclimates. For each of these bioclimates, we find different types of zonal and azonal vegetation, whose floristic composition and physiognomy are described here.