The Reproductive Strategy as an Important Trait for the Distribution of Lower-Trunk Epiphytic Lichens in Old-Growth vs. Non-Old Growth Forests

Giorgio Brunialti,Luisa Frati,Paolo Giordani,Sonia Ravera

doi:10.3390/f12010027

Giorgio Brunialti, Luisa Frati + Show 2 more

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https://doi.org/10.3390/f12010027

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Abstract

(1) Research Highlights: The work studied the beta diversity patterns of epiphytic lichens as a function of their reproductive strategies in old-growth and non-old growth forests from the Mediterranean area. (2) Background and Objectives: The reproductive strategies of lichens can drive the dispersal and distribution of species assemblages in forest ecosystems. To further investigate this issue, we analyzed data on epiphytic lichen diversity collected from old-growth and non-old growth forest sites (36 plots) located in Cilento National Park (South Italy). Our working hypothesis was that the dispersal abilities due to the different reproductive strategies drove species beta diversity depending on forest age and continuity. We expected a high turnover for sexually reproducing species and high nestedness for vegetative ones. We also considered the relationship between forest continuity and beta diversity in terms of species rarity. (3) Materials and Methods: we used the Bray–Curtis index of dissimilarity to partition lichen diversity into two components of beta diversity for different subsets (type of forest, reproductive strategy, and species rarity). (4) Results: The two forest types shared most of the common species and did not show significant differences in alpha and gamma diversity. The turnover of specific abundance was the main component of beta diversity, and was significantly greater for sexually reproducing species as compared to vegetative ones. These latter species had also the least turnover and greater nestedness in old-growth forests. Rare species showed higher turnover than common ones. (5) Conclusions: Our results suggest that sexually reproducing lichen species always have high turnover, while vegetative species tend to form nested assemblages, especially in old-growth forests. The rarity level contributes to the species turnover in lichen communities. Contrary to what one might expect, the differences between old-growth and non-old growth forests are not strong.

Highlights

Reproductive strategies widely affect the species distribution of vascular plants, bryophytes, and lichens
(5) Conclusions: Our results suggest that sexually reproducing lichen species always have high turnover, while vegetative species tend to form nested assemblages, especially in old-growth forests
Fifteen percent (22 species) of the floristic list was represented by lichens included in the Italian Red List: one Endangered species (Alyxoria ochrocheila), 4 Vulnerable species (Agonimia allobata, Solitaria chrysophthalma, Sticta limbata, Vahliella saubinetii), 11 Near-Threatened species (Arthopyrenia salicis, Buellia disciformis, Caloplaca herbidella, Diarthonis spadicea, Lobarina scrobiculata, Nephroma resupinatum, Pachyphiale carneola, Pectenia plumbea, Ricasolia amplissima—chloromorph, Ricasolia amplissima—cyanomorph, Schismatomma ricasolii), 4 Least Concern species (Gyalecta liguriensis, Lobaria pulmonaria, Parmeliella testacea, Ramalina subgeniculata), and two Data-Deficient species (Lepra slesvicensis, Ochrolechia dalmatica)

Summary

Introduction

Reproductive strategies widely affect the species distribution of vascular plants, bryophytes, and lichens. Relying on different dispersal vectors such as wind, water, or animals, vascular plants have evolved a broad range of dispersal modes or strategies [1,2], using generative (such as spores, seeds, or fruits) and vegetative (such as fragments of stems, stolons, rhizomes, or bulbils) diaspores [3]. Lichen propagules (diaspores) contain cells from both partners and represent an essential evolutive solution to this problem [6]. This vegetative reproduction grants a reasonable survival rate and success for the establishment of new lichen thalli [7]. Still, it is characterized by a low dispersal ability [8]. Some authors have shown that diaspores usually have a dispersal range of about 10–100 m for Lobaria pulmonaria [9,10,11,12], and up to 30 m for Evernia prunastri, Ramalina farinacea [13], and Hypogymnia physodes [14]

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