DOI: 10.5061/dryad.r7sqv9s9s
title: Data on epiphytic lichens along elevational gradients in South Tyrol, Italy

description: 1. Several studies have evaluated lichen responses in terms of shifts in
 species climate suitability, species richness, and community composition.
 In contrast, patterns of co-occurrence among species that could be related
 to complex species interactions have received less consideration. Biotic
 interactions play a major role in shaping species niches, fitness, and
 adaptation to new environments. Therefore, considering the specific
 relationships among co-occurring species is essential to further deepen
 our knowledge of biodiversity response to climate change. In this
 perspective, the analysis of lichen ecological networks across elevational
 gradients may provide a powerful tool to understand how communities are
 structured and how biotic interactions are modulated by changing climatic
 conditions. 2. We evaluated the contribution of environmental and species
 biological attributes to the structure of epiphytic lichen-host tree
 networks. Specifically, we studied lichen communities considering two
 different network levels: the whole lichen community, and groups of lichen
 species that presented similar biological traits. In this framework, we
 (1) characterized the structure of the epiphytic lichen-host tree
 networks; (2) assessed how network structure varied with climate, forest
 attributes, and community trait diversity; and (3) evaluated the role that
 biological traits played in the connections established between
 co-occurring lichens. 3. On one hand, results indicate that epiphytic
 lichen communities are dominated by local segregation, suggesting habitat
 specialization among lichens within their host tree, and that climatic
 conditions and, to a lesser extent, lichen diversity are the main drivers
 of community assemblage. On the other hand, the role of lichen species in
 the networks depends on their particular biological traits, supporting the
 hypothesis that biological traits contribute to shape network structure by
 influencing the ability of the species to interact between each other.
 These findings warn about the potential impact of climate change on
 epiphytic lichen communities. 4. Synthesis. This study builds towards a
 better understanding of lichen community assembly and on biodiversity
 response to climate change in forest alpine ecosystems. In particular, our
 results highlight the value of lichen-tree networks to inform about
 assemblage processes acting at different organizational levels and
 indicate that lichens might become one of the most threatened groups under
 global change scenarios.
description: Reference paper for methodological aspects is: Nascimbene J.,
 Marini L. 2015. Epiphytic lichen diversity along elevational gradients:
 biological traits reveal a complex response to water and Energy.
 <i>Journal of Biogeography</i>, 42: 1222-1232.
 doi:10.1111/jbi.12493
description: The file DATASET_ELEVATIONAL_tree_species_traits includes
 information on: Type of stand
 (multilayered/eveaged) height of the releve on the
 trunk (H on the trunk (cm)) exposition of the releve on
 the trunk (NSEW) Thallus growth form (Crustose,
 Foliose, Fruticose, Leprose, Squamulose) Photobiont
 type (Ch = coccoid green algae; Tr = trentepohlioid algae)
 Reproduction strategy (S = sexually; Ai = asexually with isidia;
 As = asexually with soredia; Af = asexually by thallus
 fragmentation) For each species a frequency datum is
 associated expressed by the number of the quadrats of the sampling grid in
 which the species occurred (1-5)  
 The file DATASET_ELEVATIONAL_tree_features includes information
 on the features of the sampled trees: circumference (cm), Age (years),
 Cervices depth
 (cm), Heigth first branches (m), canopy
 length (m), canopy openness (%).