Growth and vitality of transplanted individuals of the critically endangered cyanolichen Erioderma pedicellatum
Master thesis

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Date
2024Metadata
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- Master’s theses (MINA) [780]
Abstract
Lichens are a diverse group of species that make up one of the most successful symbiotic partnerships on Earth, yet increasing pressure from human-driven climate and area change is a significant threat to their biodiversity. The critically endangered cyanolichen Erioderma pedicellatum is currently confined to a small location in Rendalen, Norway, as its prehistoric occurrences in Trøndelag have disappeared. This study aimed at assessing the growth and vitality of transplanted individuals of E. pedicellatum in an area where it historically existed, and thus to what extent transplantation experiments have the potential to be a conservation method for this species in Norway.
54 individuals of E. pedicellatum were transplanted to the Gartlandselva nature reserve, where they spent 172 days from late May to early November of 2023. Transplantation success was analyzed through parameters such as relative growth rate in weight (RGR), relative growth rate in area (RTaGR), and specific thallus mass (STM). In addition, parameters of vitality were analyzed through measurements of photosystem II efficiency in dark- and light-adapted states (Fv/Fm and ETRapp, respectively). Environmental factors at the transplantation site such as light transmittance, soil and bark pH, position in the terrain, vegetation composition, and diameter at breast height of the host trees, were also registered.
The results indicate that transplantation indeed has the potential to be a conservation strategy for this species in Norway. Many of the transplants had positive RGR (n = 23), even more had positive RTaGR (n = 36), and most of them had reduced STM, indicating that they grew thinner post-transplantation, as an adaptation to shade. The transplants that experienced positive RGR were associated with higher light levels and higher soil pH. The parameters of vitality remained relatively stable, except for a slight increase in Fv/Fm, likely as a response to lower light conditions. These findings not only supplement the ecophysiological knowledge about this species in Norway but also demonstrates that transplantation experiments have potential to conserve this species. Future research should aim at conducting long-term transplantation experiments, that includes many seasons as well as thorough measurements of the environmental conditions at the transplantation site, to evaluate if this species is able to establish viable populations over time.