Epiphytic lichen synusiae and functional trait groups in boreo‐nemoral deciduous forests are influenced by host tree and environmental factors

Abstract

Deciduous forests with temperate broad‐leaved tree species are particularily important in terms of biodiversity and its protection, but are threatened habitats in northern Europe. Using multivariate analyses we studied the effect of forest site type, environmental variables and host tree properties on epiphytic lichen synusiae as well as on the composition of species‐specific functional traits. Epiphytic lichens were examined on Acer platanoides, Fraxinus excelsior, Quercus robur, Tilia cordata, Ulmus glabra and U. laevis in two types of forests: Humulus‐type floodplain forests and Lunaria‐type boreo‐nemoral forests on the talus slopes of limestone escarpment (klint forests). Klint forests located near the seashore were under greater maritime influence compared to floodplain forests located in inland Estonia which experience stronger air temperature contrasts. In addition to stand level and climatic variables, tree level factors (bark pH, trunk circumference and cover of bryophytes) considerably affected the species composition of the lichen synusiae. Overall, 137 lichen species were recorded, including 14 red‐listed species characteristic of deciduous trees. We defined 13 lichen societies and showed their preference to forests of a specific site type and/or host tree properties. In forests of both types, most of the epiphytic lichens were crustose, and had apothecia as the fruit bodies and chlorococcoid algae as the photobiont. However, the proportion of lichens with a foliose or fruticose growth form, as well as the proportion of lichens with vegatative diaspores, were higher in floodplain forests. In klint forests with a stronger influence from the wind, crustose species completely dominated, while species with vegetative diaspores were rare and most species dispersed sexually. Lichens with Trentepohlia as the photobiont were characteristic of these forests, and lichens with lirellate ascomata were prevailing, indicating the great uniqueness of the kint forests for epiphytic lichens in the boreo‐nemoral region.

Red List of Estonian lichens: revision in 2019

“…(e.g. Jüriado et al, 2003;Lõhmus & Kruustük, 2010;Lõhmus & Lõhmus, 2011;Degtjarenko et al, 2016;Marmor et al, 2017;Jüriado & Paal, 2019), while dry alvar grasslands with very thin soil layer and sand dunes are suitable for ground layer community taxa (e.g. Leppik et al 2013Leppik et al , 2015Jüriado et al, 2016).…”

“…Since 1979, five Red Lists have been compiled in Estonia: in 1979, 1988, 1998, 2008-2019 were included for the first time into the second Red List in 1988 (Anonymous, 1993). Conventional system of threat categories and intuitive-emotional criteria for defining these categories were used in three earlier Red Lists.…”

New assessment of Least Concern lichens in the Red List of Estonia: are common species still common?

“…1); (b) different habitats had to be represented by the study sites whereas the communities recently less investigated in terms of lichens (e.g., old manor parks and cemeteries, coastal areas, rocky habitats etc.) had to be preferred; (c) although forests are the most important community for lichens in the hemiboreal vegetation zone, only a smaller part of our study sites had to be located in forest habitats as forests lichens have been relatively well investigated in Estonia during the last decade (for example, Marmor et al, 2012Marmor et al, , 2013Marmor et al, , 2017Lõhmus et al, 2012;Jüriado & Paal, 2019;, Liira et al, 2020; (d) all our forest study sites had to be located in protected territories.…”

Morphological and Chemical Traits of Cladonia Respond to Multiple Environmental Factors in Acidic Dry Grasslands

“…The analysis of functional traits to explore species' responses to environmental factors is increasingly applied also to lichens [1,2]. However, most studies have addressed epiphytes (e.g., [3][4][5]), whereas terricolous lichens are relatively less investigated (e.g., [6][7][8]) despite their ecological importance (e.g., [9]) and conservation concern [6,10]. It is therefore of utmost importance to understand the relationships driving terricolous species' responses to environmental stresses, particularly in the current context of global change [2,5,6] Terricolous lichen communities are often dominated by species of the genus Cladonia.…”