Bryophyte richness of soil islands on rocky outcrops is not driven by island size or habitat heterogeneity

Abstract

Th e species-area relationship (SAR) is one of the oldest and most studied ecological models, having even served as the foundation of the Th eory of Island Biogeography. Nevertheless, the relative importance of habitat heterogeneity to SAR remains poorly understood. Our aim was to test the relative importance of habitat heterogeneity to the SAR of bryophyte assemblages of soil islands of rocky outcrops in the semi-arid region of Brazil. We randomly selected 15 to 20 soil islands on each of four outcrops for a total of 59 soil islands, and calculated the area, mean depth, and number of substrates for each. We used Generalized Linear Models (GLM) to test the SAR with two models, one using species richness and another using life-form richness as the dependent variables. We found no positive relationship between area and habitat heterogeneity, nor any evidence of a SAR, such as a positive relationship between area and species or life-form richness neither between habitat heterogeneity and species richness. However, our fi ndings did show that life-form richness is related to bryophyte species richness on the soil islands. We conclude by suggesting that not only can microclimate infl uence bryophyte richness, but opportunistic colonization by bryophytes is also important.

The response of the moss Campylopus lamellatus (Leucobryaceae Schimp.) post El Niño: a case study in the Caatinga

“…(= Campylopus pilifer Brid. according Gama et al 2017) stands out as an abundant species on rocky outcrops (Silva et al 2014(Silva et al , 2018Penãloza-Bojacá et al 2018). It is an acrocarpic pioneer moss of rocky outcrops (Oosting & Hess 1956;Scarano 2002), and is widely distributed worldwide.…”

Geochemical alkalinity and acidity as preferential site-specific for three lineages liverwort of Aneura pinguis cryptic species A

“…7 ). The course of this process was described by Silva et al 15 as the species-area relationship (SAR), when concluding that not only microclimate can influence bryophyte richness, but opportunistic colonisation by bryophyte is also possible. This opportunistic colonisation has been reorientated in our study to the chemical composition of the ecological growth sites of A. pinguis lineages.…”

“…Adaptability of bryophytes to specific habitats was broadly investigated and still, no full compromise has been retained 11 – 15 . Growth conditions and ecological as well as preferential features of bryophytes require additional and extensive research involving jointly genetic parametrisation and soil (growth substrata) characteristics, particularly for genetic lineages 16 .…”

“…Are alkaline elements and the resulting pH enough for elucidating the calciphilous and acidophilous characters of A. pinguis ? Field research without genetic characteristics 15 , 16 lead most frequently to pointing out at some interactions and trends, but doubtful statements emerge.…”

Island biogeography: an avenue for research in bryology

“…the Island Biogeography theory has been applied to continental island systems in bryophytes in a few instances (Q15). In soil islands of rocky outcrops in the semi-arid region of Brazil, Silva et al (2018) for example failed to evidence a significant species-area relationship, which they interpreted in terms of random, opportunistic colonization. due to relative similarities between trees and oceanic islands in terms of geographic isolation and evolution of the physical properties during their respective ontogenetic development, the application of the Island Biogeography theory in general and the general dynamic Model of Island Biogeography (Whittaker et al 2008) in particular, has been of relevance in the case of epiphytic systems (taylor & Burns 2015).…”