Biomass and diversity of epiphytic liverworts along environmental gradients in a cloud forest in Mexico

Abstract

ABSTRACT Introduction Bryophytes can reach levels of coverage sufficient to influence key ecological processes; for example, their water retention capacity can supply an appreciable amount of humidity to forest ecosystems. The variation in biomass and diversity of epiphytic liverwort species in a Mexican cloud forest (CF) in the state of Hidalgo was estimated along elevation and latitude gradients, as was the relationship between epiphytic liverwort structural attributes and environmental factors. Methods Liverwort species were sampled in three municipalities with CF in Hidalgo State, at elevations of 1345–2019 m. In each municipality, two 0.1 ha plots were located at the two extremes of the gradient. For each of 10 trees per plot, three 10 × 10 cm areas of bark were selected as microplots, and from each microplot, samples of liverwort were obtained to determine structural data for the liverworts. Key results Species diversity was highest at the upper elevation level (1985–2001 m), and lowest at the lower elevation level (1345–1375 m). The highest dry and saturated weight values (15.20 g and 83.30 g, respectively) were found at lower elevations, and the lowest (11.78 g and 60.04 g, respectively) at high elevations. Conclusion Species diversity was positively related to elevation gradient, and species biomass decreased gradually with elevation. Beta diversity values were not associated with geographical distance between sites. Local factors, such as light input, available area, phorophyte species, humidity and temperature, may have more influence on the growth of epiphytic liverworts than elevation or geographical distance.