Changes in Functional and Taxonomic Diversity and Composition of Corticolous Lichens in an Altitudinal Gradient in Colombia

Abstract

The variation of the diversity, composition, functional diversity and species richness of lichen communities along an altitudinal gradient in the Chocó biogeographic region of the department of Valle del Cauca, Colombia, is evaluated basing on 2732 samples belonging to 690 species of corticolous lichens. The dominant families were Graphidaceae, Parmeliaceae, Lobariaceae and Pyrenulaceae. Alpha lichen diversity showed a concave pattern with respect to altitude, and the zones at low and high elevations had greater diversity. Beta diversity and total richness estimated by rarefaction for locality presented a bell-shaped pattern, with a peak at 1600 m. Lichen functional traits strongly changed with the increase of altitude. Functional diversity presented the same pattern of total richness estimated by rarefaction. These results suggest that the lichen communities of the altitudinal extremes are structured by a strong environmental filter effect, while in the intermediate zones there is an overlap of functional traits, which is reflected in both a high functional and taxonomic diversity. The results suggest that the functional traits used are good substitutes for species to study altitudinal patterns. The high number of indicator species for the altitudinal extremes implies that in a context of climate change, these zones will be more susceptible to the loss of species.

Turnover of Lecanoroid Mycobionts and Their Trebouxia Photobionts Along an Elevation Gradient in Bolivia Highlights the Role of Environment in Structuring the Lichen Symbiosis

“…Climate does matter for lichens. There is turnover in lichenized fungi along elevation gradients, including those in the northern Andes ( Wolf, 1993 ; Soto-Medina et al, 2019 ) that inspired Humboldt’s work. Furthermore, the mycobiont–photobiont interaction that defines the lichen symbiosis is affected by environmental conditions at micro and macro scales (e.g., James and Henssen, 1976 ; Peksa and Škaloud, 2011 ; Singh et al, 2017 ).…”

Composition and Specialization of the Lichen Functional Traits in a Primeval Forest—Does Ecosystem Organization Level Matter?

“…However, assessing the quality of the environment simply based on lichen species diversity is not sufficient due to the high site specificity and context dependency of the patterns revealed, thus affecting their low transferability into similar ecosystem types of different geographical zones. Current trends place emphasis on describing the functional composition that provides additional information about biodiversity patterns and community assembly processes [8][9][10][11]. Therefore, Forests 2021, 12, 485 2 of 23 application of the functional diversity approach in lichenological studies provides more mechanistic insights into the importance of environmental factors driving lichen biodiversity changes more accurately than the traditional approach based exclusively on species richness.…”

“…High functional diversity, e.g., in natural forests or in forests with low human influence, may be an indication of the high microhabitat diversity available for lichens, while low functional diversity may express simplification of lichen community composition due to habitat homogenization, e.g., in intensively managed stands [3,10]. Functional traits enable us to more clearly understand the specific adaptations of lichens to environmental conditions [2,8,[11][12][13] and, furthermore, to assess the degree of naturalness of the entire ecosystem or the degree of its anthropogenic transformation [2,9,10,14,15]. Understanding the patterns of occurrence of lichen functional traits in different microhabitats and forest communities can also help to assess changes in the lichen biota and across the entire forest ecosystem, resulting from forest management, pollution, changes in the structure of forests due to fires, insect outbreaks and tree diebacks [2,9,10,16,17].…”

“…Ascospore dark pigmentation (ascospores that are dark-pigmented; ascospores that are not pigmented). The wall of ascospores can include pigments and melanins, which may relate to specific microhabitats [8], e.g., habitats of higher insolation to which species with dark ascospores are adapted [8,11]. 4.…”

“…Ascospore septation (ascospores that are one-celled, two-celled, multi-celled with transverse septa only or muriform). This trait is probably connected with lichen dispersion and specialization to specific microhabitats [31], e.g., one-celled or twocelled ascospores are dominant in harsher environmental conditions such as higher insolation and temperature fluctuations, while multi-celled ascospores are dominant in milder environments [11].…”