DOI: 10.5061/dryad.51c59zw9d
title: Nuanced qualitative trait approaches reveal environmental filtering and phylogenetic constraints on lichen communities

description: We propose that a qualitative trait approach based on more detailed
 nuanced traits may reveal previously overlooked patterns, especially when
 combined with phylogenetic perspectives. By sampling epiphytic lichens and
 using a functional approach based on nuanced qualitative traits, such as a
 much greater resolution over photobiont identity, type of cortex and
 chemical compounds, we evaluated the effects of environmental filtering
 and phylogenetic constraints on community assembly along natural
 succession of Atlantic rainforest. We found changes in taxonomic,
 functional and phylogenetic composition, structure and diversity.
 Functional traits such as photobiont genera, type of cortex, reproductive
 structures, propagule size and protection strategies showed strong
 responses to succession. Mature forests with a closed canopy impose strong
 environment filtering that is reflected in lichen species turnover,
 limiting diversity, but also holding different functional and phylogenetic
 composition. The use of a nuanced qualitative trait approach may overcome
 some of the limitations of using this type of traits and show the
 importance of often overlooked key lichen functional traits, including
 presence of carbon concentrating mechanisms in photobionts and cortex
 properties. Furthermore, this is the first study showing how patterns of
 phylogenetic assembly along forest succession structure lichen
 communities.
description: This study was carried out in forest fragments in the river basin
 Maquiné, between
 51<sup>o</sup>21’-50<sup>o</sup>05’W and
 29<sup>o</sup>20’-29<sup>o</sup>50’S, northeastern
 Rio Grande do Sul state, southern Brazil, where the climate is classified
 as subtropical humid (Moreno 1961). The annual mean temperature varies
 from 13ºC to 22ºC and the annual precipitation is around 1400 and 1800 mm
 (Hasenack and Ferraro 1989). The original vegetation is composed of
 Atlantic rainforests and corresponds to the southern distribution limit of
 one of the most important and rich tropical forests in the world (Myers et
 al. 2000). The demographic density in the region is only 11
 inhabitants/km<sup>2 </sup>(IBGE 2010), and the main economic
 activity is small scale agriculture (subsistence farming), which means
 that we do not expect any important anthropogenic influence on lichen
 communities. Lichen communities were sampled in four different sites, each
 of them located in different valleys and each containing stands of three
 different stages of forest succession: initial - between 6 and 10 years of
 natural regeneration, intermediate - between 12 and 20 years, and late -
 between 40 and 60 years (Koch et al. 2013). The criteria used for
 selecting the areas were the existence of reliable information about the
 forest age and the possibility of finding all stages in a similar range of
 altitude and climatic conditions. We estimated stand ages by interviewing
 local inhabitants, only those living in the areas for at least 40 years.
 In each successional stage from each site two sampling units (SUs) were
 set (for a total of twenty-four SUs), where three randomly selected adult
 trees were sampled, all in a radius of 5 m. These tree individuals had CBH
 &gt; 18 cm (CBH: circumference at breast height – 1.30 m from the
 ground), with a straight stem without branches below 1.50 m, without a
 smooth or peeling cortex. In total, we sampled 72 trees distributed in 24
 SUs in four valley slopes, varying from 30 to 250 m of altitude.We sampled
 lichens on the tree stems from 30 to 150 cm from the ground, in regular
 intervals of 10 cm, which represented 13 height levels, using the rubber
 band method (Marcelli 1992). This method consists in placing a rubber
 band, gradually marked in percent-coverage classes from 0 to 100% of
 coverage around the stem. The length of the rubber bands varied according
 to the stem circumference i.e., the percent coverage is always relative to
 the tree size. Lichen species coverage per tree was the sum of the percent
 coverage (standardized according to the stem circumference) and the
 coverage of each species in the SU corresponded to the mean value of the
 three sampled trees.