Impact of forest management on threatened epiphytic macrolichens: evidence from a Mediterranean mixed oak forest (Italy)

Abstract

Biogeosciences and Forestry Biogeosciences and Forestry Impact of forest management on threatened epiphytic macrolichens: evidence from a Mediterranean mixed oak forest (Italy) Luca Paoli (1) , Renato Benesperi (2) , Zuzana Fačkovcová (3) , Juri Nascimbene (4) , Sonia Ravera (5) , Marco Marchetti (5) , Barbara Anselmi (6) , Marco Landi (7) , Sara Landi (8) , Elisabetta Bianchi (2) , Luca Di Nuzzo (2) , Anna Lackovičová (3) , Andrea Vannini (9) , Stefano Loppi (9) , Anna Guttová (3) Forest management practices may heavily affect epiphytic cryptogams. This study was conceived in March 2016, as soon as we were informed about an authorized logging for timber within a Mediterranean mixed oak forest in Tuscany (central Italy), which threatened a large population of the forest macrolichen Lobaria pulmonaria (L.) Hoffm., composed of hundreds of fertile thalli. Lobaria pulmonaria is often used as an ecological indicator of high quality habitats hosting rare lichens, and in general, cryptogams worthy of conservation. The species has suffered a general decline throughout Europe as a consequence of air pollution and intensive forest management, and currently it is red-listed in several countries, where it is considered also as a "flag species". We estimated that 40% of the lichen biomass (8.5-12.3 kg ha-1) has been lost due to logging operations (in the core area, up to 1.8 kg every 100 m 2), in particular large and fertile thalli. One year after the conclusion of logging operations, the analysis of chlorophyll fluorescence emission (indicator of the photosynthetic performance of the lichen photobionts), revealed a significant reduction of the vitality of the thalli on retained-isolated trees. The article provides issues for conservation in Mediterranean oak forests and outlines the outmost importance of ensuring the safeguard of forest ecosystems hosting fertile populations of this model species, especially in the case of unprotected forests.

Vitality and Growth of the Threatened Lichen Lobaria pulmonaria (L.) Hoffm. in Response to Logging and Implications for Its Conservation in Mediterranean Oak Forests

“…They can be directly destroyed/lost due to the logging of the trunks for timber production, as already occurred in the investigated oak forest (loss of 40% of L. pulmonaria biomass) [48].…”

“…A transplantation experiment with L. pulmonaria beginning during a sunny and dry period induced extensive and irreversible bleaching after only 40 days [32]. These effects, mostly studied in boreal forests (e.g., [62,63]), can be exacerbated in Mediterranean oak forests [48], where high light and temperature (especially during summer), together with the decoupling of moisture and light availability across an annual cycle, are supposed to influence the generation time of L. pulmonaria in the long-term [33]. The results of our transplant experiment outline that the exposure in a logged stand has negative effects on the growth capacity of non-meristematic fragments.…”

“…The logged stand (about 4.4 ha) was part of a local hotspot of L. pulmonaria, which had a patchy distribution and colonized more than 1000 trees. Prior to logging, the overall biomass of L. pulmonaria in the study area was 15.8-19.6 kg ha −1 [48]. Oak forests in Tuscany are mainly managed by a coppice system with standards and rotation cycles of 18-20 years [51].…”

“…Additionally, air pollution still may limit recolonization of potentially suitable forest habitats [44]. However, despite being declining and threatened in Southern Europe [43,[45][46][47], the species is not often recognized in conservation policies in Mediterranean regions [48].…”

“…This research began in 2016 with a legal logging in a Mediterranean mixed oak forest in Tuscany, Central Italy, that heavily impacted a large population of L. pulmonaria. It was estimated that 40% of L. pulmonaria biomass (8.5-12.3 kg ha −1 ) was lost (in the mostly colonized area, up to 1.8 kg 100 m −2 ), including large and fertile thalli [48]. More than one year later, the analysis of chlorophyll a fluorescence emission revealed a significant reduction of the vitality of the thalli left on retained-isolated trees [49].…”