Effects of selection cutting on the abundance and fertility of indicator lichens Lobaria pulmonaria and Lobaria quercizans

Abstract

Summary 1.Although selection cutting is probably less harmful to forest ecosystems than clear cutting, its effects on biodiversity remain largely unexplored. We investigated the previously unstudied effects of selection cutting on the abundance and fertility of two dominating species of epiphytic lichens, Lobaria pulmonaria and Lobaria quercizans , in a northern hardwood forest of New Brunswick, Canada. 2. Twenty-eight forest stands were selected representing two contrasting silvicultural treatments: fairly recent selection cuts (5-9 years) and 'uncut' stands that had been subjected to low-intensity single-tree cutting at least 35 years ago. Within each stand, we quantified the abundance and fertility of lichens on 36 trees together with selected forest stand variables. 3. Although both species had survived harvesting, the abundance of L. quercizans and L. pulmonaria was four and five times higher, respectively, in uncut stands than in selection cuts. The most important predictive factors for lichen abundance at the stand level were total basal area and canopy closure, which were much lower in selection cuts. Furthermore, the abundance of both species at the tree level was significantly correlated with tree size. 4. Most interestingly, fertile L. quercizans and L. pulmonaria were, respectively, five and 26 times more frequent in uncut stands. In addition, for L. pulmonaria the fertility frequency was only 3% in selection cuts, compared with 37% in uncut stands. The fertility of both lichen species was strongly correlated with their abundance at the tree level. Synthesis and applications.Our results indicate that selection cutting has a strong impact on the abundance and fertility of these two Lobaria species, and that studies ignoring fertility may underestimate the negative effects of forestry on lichens. To reduce the negative effects we have three recommendations. (i) Large trees from old seral stages should be retained during selection cuts.(ii) The cutting cycle should be extended and the basal area removed should be reduced. These actions would improve the microclimate, increase the amount of suitable habitat and prolong the time window for lichen colonization in selection cuts. (iii) Some mature deciduous forest stands should be protected at the regional scale. This would promote the long-term persistence of large, sexually reproductive lichen populations and concurrently benefit all species tightly linked with mature hardwood forests.

Fine spatial pattern of an epiphytic lichen species is affected by habitat conditions in two forest types in the Iberian Mediterranean region

“…The long-term persistence of small clusters of colonized oak trees might promote the future establishment and development of L. pulmonaria in remaining phorophytes in oak stands, because these will act as a propagule source. This may be a general rule for L. pulmonaria (Price & Hochachka 2001;Edman et al 2008;Fritz et al 2008), but our results suggest that this approach may not work efficiently in beech stands. Thus, specific recommendations on the spatial pattern and density of remnant trees are urgently needed in order to take full advantage of their potential as a source of lichen propagules (Sillett et al 2000;Hilmo & Sástad 2001).…”

“…Factors, such as tree size, tree age, microclimatic conditions, and forest quality, have been studied to better understand colonization by epiphytic organisms (Hedenás et al 2003;Snail et al 2003Snail et al , 2004Edman et al 2008). However, distance-dependent dispersal cannot be ignored (Walser 2004;Óckinger et al 2005;Pharo & Zartman 2007;Johansson 2008).…”

Edge effects on the lichen genus Lobaria in Atlantic Canadian Forests

“…During our study a transition zone was observed where the abundance of the Lobaria species increased progressively the further away from the edge of the harvest, where humidity and canopy closure was higher. Edge effects have been studied using sensitive lichens by several researchers in different regions (Esseen and Renhorn 1998, Rheault et al 2002, Edman et al 2008. The main variables causing edge effects were relatively consistent among other studies: changes in temperature, sun exposure, wind exposure, and moisture (Esseen 1994, Sillet 1994, Lücking 1997, McMullin et al 2010.…”

“…Lichens are a group of organisms that are sensitive to disturbance, particularly those in the genus Lobaria (Edman et al 2008), which is common in mature, undisturbed deciduous-dominated forests of the Acadian Forest Region (Gowan and Brodo 1988, Cameron 2002, McMullin et al 2008, McMullin et al 2012. Species of Lobaria are sensitive to changes in light, temperature, and relative humidity (Gauslaa and Solhaug 1999).…”

Threatened forest lichen Lobaria pulmonaria - its past, present and future in Estonia

“…In contrast to its overall European status, L. pulmonaria is still frequent in Fennoscandia and in the Baltic region. Here the lichen has mainly been recorded in small and fragmented old forest patches in managed forests (Auzinš & Ek, 2001;Gu et al, 2001;Andersson et al, 2003;Pykälä, 2004;Jüriado & Liira, 2009), and it prefers large-diameter host trees (Riiali et al, 2001;Öckinger et al, 2005;Gu et al, 2001;Mikhailova et al, 2005;Edman et al, 2008;Belinchon et al, 2009). In highly humid conditions, L. pulmonaria also occurs on younger trees and on rocks (Hakulinen, 1964;James et al, 1977;Carlsson & Nilsson, 2009).…”