Richness of Lichen Species, Especially of Threatened Ones, Is Promoted by Management Methods Furthering Stand Continuity

Abstract

Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin), the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m2 comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging), various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks). We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1) conserving unmanaged forests, (2) promoting silvicultural methods assuring stand continuity, (3) conserving old trees in managed forests, (4) promoting stands of native deciduous tree species instead of coniferous plantations, and (5) increasing the amount of deadwood in forests.

Bryophyte and macrolichen diversity show contrasting elevation relationships and are negatively affected by disturbances in laurel forests of Madeira island

“…As species richness of perennial and long‐lived bryophytes and of groups depending on old‐growth forest attributes (several liverworts, endemic bryophytes, foliose lichens, epiphytic cyanobacteria lichens) declined with disturbances, the conservation of undisturbed forest stands is of particular importance. This conclusion is in line with many other studies pointing out the conservational value of mature trees and old‐growth forest attributes for the conservation of specialist species (Boch, Prati et al, ; Gustafsson et al., ; Patiño et al., ).…”

“…Bryophyte and macrolichen richness per plot is quite high (as we only sampled 4 m 2 of forest floor and 0.64 m 2 of bark surface) compared with other regions (for lichens: Boch, Prati et al., ; Cleavitt, Clyne, & Fahey, ; Nascimbene & Marini, ; for bryophytes: Horvat, Heras, García‐Mijangos, & Biurrun, and Müller et al., ). We did not sample crustose lichen species, but as their richness is often much higher than that of macrolichens and both diversities are positively correlated (Bergamini, Stofer, Bolliger, & Scheidegger, ), we assume that the total lichen richness per plot also would exceed average values of most parts of other European countries.…”

Large proportion of wood dependent lichens in boreal pine forest are confined to old hard wood

“…Lichens are a species rich group in boreal forests, being found on bark (corticolous lichens), soil (terricolous lichens), rocks (saxicolous lichens), and decorticated dead wood (lignicolous lichens) (Boch et al 2013). The loss of a tree's bark results in a major shift in lichen species composition (Lõhmus and Lõhmus 2001).…”

Dead standing pine trees in a boreal forest landscape in the Kalevala National Park, northern Fennoscandia: amount, population characteristics and spatial pattern

“…Height is the height in the local topography. Stumps is the number of stumps in the grid that kelo habitats are continuously available over relatively short distances to their accompanying species such as epiphytic lichens (Boch et al 2013). An interesting further question would be how this pattern is reflected in the dispersal abilities of kelo-associated species and how these species might be dependent of patterns of kelo availability in time and space.…”