Latitudinal patterns in pteridophyte distribution of continental Chile

Abstract

Chilean vegetation has been described based on dominant trees and shrubs, giving little attention to less conspicuous plants such as pteridophytes sensu lato (ferns and lycophytes). These plants have different ecological demands and reproductive strategies than woody plants and are excellent tools to recognize vegetation zones. In the present study we analyze the distributional patterns of the 124 pteridophyte taxa occurring in continental Chile, regarding species richness and habitat preferences distribution. Using Jaccard’s similarity index and grouping analysis, we obtained 5 pteridophyte zones that are significantly different from each other. Species richness distribution showed unimodal pattern with latitude, increasing from 17º S toward south up to a maximal value at 40º S and abruptly decreasing southward. These patterns are coincident with the habitat preference where the xerophytic species tend to decrease with latitude. In contrast, epiphytic pteridophytes increased with latitude, as temperate forests appear. Terrestrial hygrophytic species were present in all areas, but showed a southward increase. These distributions suggest an important role of the precipitation patterns, which is considered a limiting resource for pteridophytes’ life cycle.