Scaling α‐ and β‐diversity: bryophytes along an elevational gradient on a subtropical oceanic Island (La Palma, Canary Islands)

Abstract

Questions We addressed three questions: (1) what is the variation of α‐ and β‐diversity of bryophyte communities across spatial scales in an elevational gradient; (2) is spatial variation characteristic of different phylogenetic (mosses/liverworts) and/or ecological groups (terrestrials/epiphytes); and (3) what is the contribution of species richness and species replacement (true turnover) to β‐diversity along the elevational gradient? Location La Palma, Canary Islands, Spain. Methods An elevational transect spanning 0–2200 m a.s.l was sampled at altitudinal intervals of ca. 200 m, two 10 m × 10 m plots were established at each elevation and inside each plot three 2 m × 2 m quadrats were randomly selected. Within each quadrat, bryophytes were sampled in three replicate microplots of 10 cm × 5 cm, for each substrate: soil, rocks, leaves, humus, decaying wood and tree trunks at three heights. We evaluated α‐ and β‐diversity at plot and elevational level for all bryophytes and for phylogenetic and ecological groups. Values of β‐diversity were further decomposed into replacement and richness differences. We tested the relationship between α‐ and β‐diversity and elevation using linear models with and without a quadratic term (elevation2) in an AICc‐based framework. Results A total of 121 species were recorded along the transect. Alpha‐diversity showed a hump‐shaped pattern with elevation for all bryophytes, liverworts and epiphytic species, however, terrestrial species and mosses displayed no clear pattern. Species replacement was the main driver of β‐diversity for all bryophytes and also for mosses and terrestrial species, and at different scales (elevational belt and quadrat). The contribution of species replacement increased with elevation, except for epiphytes and terrestrials. Conclusions Our study contributes towards an understanding of the spatial organization of bryophyte diversity at different scales along an insular elevational gradient. We showed that bryophyte diversity was mostly influenced by species replacement at the largest scale. The observed differences in β‐diversity decomposition between bryophyte phylogenetic and ecological groups could be dependent on climatic conditions and substrate availability. The strong differences observed along the elevational gradient related to true turnover are especially important in the current global change scenario.

Species richness and beta diversity patterns of multiple taxa along an elevational gradient in pastured grasslands in the European Alps

“…2 ). Some studies on bryophytes performed in warmer climate zones found a hump-shaped relation of richness to elevation 56 , 57 . However, in the temperate zone, an increase of richness with elevation for lichens and bryophytes was found also by Nascimbene and Marini 27 and Spitale 28 who explained their results with a negative relationship of richness with temperature and associated conditions such as slower evaporation rates.…”

Natural and human-impacted diversity of bryophytes along an elevational gradient on an oceanic island (La Palma, Canarias)

“…The fieldwork was conducted from April 2012 to April 2013. The sampling design followed BRYOLAT methodology [32,33,34,35]. Within each site we studied: plots, subplots and microplots.…”

Drivers of distance‐decay in bryophyte assemblages at multiple spatial scales: Dispersal limitations or environmental control?

“…Hernandez‐Hernandez et al. () recently examined richness and turnover patterns of bryophytes at multiple spatial scales along an altitudinal gradient in the Canary Islands, but neither addressed the effect of grain size on turnover patterns, nor explored the scale dependence of environmental and geographical control on such patterns.…”