Diversity begets diversity: Phorophyte and microsite relations of foliicolous lichens in the lowland rain forest at Los Tuxtlas Biosphere Reserve (Veracruz, Mexico)

Abstract

We analyzed the structure of foliicolous lichen communities in the northernmost lowland forest of the Neotropics, Los Tuxtlas Tropical Biology Station in Veracruz, Mexico, and its dependence on phorophyte and microclimate. Along a 420‐m long transect with 15 equidistant sampling points, within a 10 m radius of each point, we sampled a total 137 phorophytes and 411 leaves. The phorophytes represented 13 species, with diverse leaf traits regarding size, texture, presence of hairs and/or glands, and longevity, including: Astrocaryum mexicanum (Arecaceae), Chamaedorea ernesti‐augustii (Arecaceae), Costus scaber (Costaceae), Guarea glabra (Meliaceae), Heliconia latispatha (Heliconiaceae), Monstera acuminata (Araceae), Myriocarpa longipes (Urticaceae), Piper hispidum (Piperaceae), Poulsenia armata (Moraceae), Pseudolmedia oxyphyllaria (Moraceae), Salacia megistophylla (Celastraceae), Siparuna thecaphora (Siparunaceae) and Syngonium podophyllum (Araceae). NDMS ordination and cluster analysis grouped the phorophytes into hierarchically structured clusters variously correlated with microsite, phorophyte species and foliicolous lichen species richness. Indicator species analysis revealed statistically significant foliicolous lichen species characteristic for terminal clusters and for phorophyte species. We conclude that the principle of “diversity begets diversity” may apply, in that phorophyte diversity influences the diversity of foliicolous lichen communities through the manifestation of subtle phorophyte preferences, best seen in well‐developed communities on leaves with higher longevity. Thus, well‐preserved forest ecosystems, with a higher diversity of suitable phorophytes, will support a higher diversity of foliicolous lichens, a phenomenon that extents to epiphytes in general.

Impact of longevity and wettability of fern leaves on epiphyll colonization in a Mexican lowland rainforest

“…With increasing leaf age, they reached their reproductive stage and concluded their short life cycles (12–36 months), which have adapted to the leaf longevity of their host plants (Pinokiyo et al, 2006). On Danaea nodosa , we found 27 species of foliicolous lichens, representing 53% of the epiphylls found on the two best angiosperm host species in “Los Tuxtlas”: Astrocaryum mexicanum and Salacia megistophylla with leaf longevities of over 50 months (Martínez et al, 2021). However, Danaea nodosa hosted only one epiphyllous lichen ( Tricharia sp.)…”

“…However, considering that epiphyll colonization occurs mainly within the last months of leaf life (Coley & Kursar, 1996), and that the richness of foliicolous lichens increases on older leaves (Mežaka et al, 2020), our last sampling time after 26 months might have been too early to detect the peak of epiphyll richness in those three fern species. On the other hand, fern species with shorter leaf longevity than Danaea nodosa had a lower richness of foliicolous lichens, perhaps because epiphyll communities at early successional stages mostly consist of few pioneer species (Martínez et al, 2021). Lichen similarity among our fern species was independent of microhabitat and microsite in part because several lichen species such as Coenogonium subluteum , Porina epiphylla and Porina rubentior grew on 5–7 fern taxa (Appendix S2) and are also frequent on angiosperm leaves in the study area (Martínez et al, 2021).…”

“…On the other hand, fern species with shorter leaf longevity than Danaea nodosa had a lower richness of foliicolous lichens, perhaps because epiphyll communities at early successional stages mostly consist of few pioneer species (Martínez et al, 2021). Lichen similarity among our fern species was independent of microhabitat and microsite in part because several lichen species such as Coenogonium subluteum , Porina epiphylla and Porina rubentior grew on 5–7 fern taxa (Appendix S2) and are also frequent on angiosperm leaves in the study area (Martínez et al, 2021). Finally, algae, such as Phycopeltis , which also established on our fern species at low cover, might facilitate the colonization of foliicolous lichens, since it is the unique photobiont of many foliicolous lichens such as Arthonia , Lyromma and Opegrapha , the preferred photobiont of Mazosia , Trichothelium (Lücking, 2008), and Porina epiphylla (Lücking & Vezda, 1998).…”

“…The identification of the epiphylls was made on the oldest leaves (12, 16.5, 23 and 26 months) of six individuals (three pinnae each) of each fern species. On these leaves, only the foliicolous lichens had reproductive structures and could be identified at species level with the help of specialized keys (Lücking, 2008), the photographic guide of foliicolous lichens (Lücking & Martínez, 2004), microscopical studies (ZEISS Stemi DV4 Spot) of the cross‐sections of the fruiting bodies (apothecia and perithecia), and bleached (10% KOH) and stained (Lugol; Martínez et al, 2021) asci and spores (Olympus BX41 with integrated camera Olympus C‐5060 Wide Zoom 5.1 MGPX). These identifications were validated by lichen specialists in our team (Paola Martínez Colín; Rosa Emilia Pérez‐Pérez).…”

“…There is a short dry season from March to May with <100 mm monthly rainfall (Álvarez‐Sánchez et al, 2016). The predominant vegetation is a lowland rainforest (Martínez et al, 2021).…”