A Pine Is a Pine and a Spruce Is a Spruce – The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities

Abstract

With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden.

Using Growth Forms to Predict Epiphytic Lichen Abundance in a Wide Variety of Forest Types

“…The number of species in each forest ranged from 263, found in a tropical montane rainforest (Ecuador) [48], to 15 species from a semi-arid lowland rainforest (Argentina) [20]. In Europe, beech forests showed the highest species richness (up to 123 species) [56], while pine forests in Sweden were the least diverse (10-20 species) [76]. In relation to growth forms, crustose inconspicuous species with apothecia, foliose narrow-lobed, and foliose broad-lobed were the most common lichen groups.…”

Consequences for bird diversity from a decrease in a foundation species—replacing Scots pine stands with Norway spruce in southern Sweden

“…differences in the resources and environments provided are in turn linked to differences in the species communities and biodiversity supported. For example, differences between Norway spruce and Scots pine stands have been found in the community composition or diversity of epiphytic lichens (Bäcklund et al 2016;Marmor et al 2013), macrofungal communities (Ferris et al 2000), and bryophytes (Augusto et al 2003;Bäcklund et al 2015). Concerns may thereby be raised that the conversion of Scots pine stands to Norway spruce may lead to changes to forest biodiversity in southern Sweden, though the specific nature of such impacts and their extent remains largely unknown.…”

Diversity of lichens and allied fungi on Norway spruce (Picea abies) in the middle boreal forests of Republic of Karelia (Russia)

“…The majority of studies report fewer lichen species for spruce, generally ranging from 20 to 90. For example, 122 species were recorded for Picea abies in Norway (Holien, 1997), 83 in southern Finland (Kuusinen & Siitonen, 1998), 53 in Sweden (Bäcklund et al, 2016) and 86 in southern Estonia (Marmor et al, 2013). In the East of European Russia, in Komi Republic, 152 lichen species were recorded on Picea spp.…”

“…Furthermore, several ecological studies emphasize factors controlling epiphytic lichen diversity and distribution on trunks and branches of spruce trees (e.g. Hilmo, 1994;Nascimbene et al, 2009Nascimbene et al, , 2010Bäcklund et al, 2016).…”