Climate change is a threat to biodiversity, yet some organisms are more impacted than others. Lichens, due to their physiology, are among the most sensitive organism to climatic variations. An increasing number of studies recognize the importance of microclimatic factors to influence species distribution and response to climate change. For example, the climate experienced by an organism inside a forest could deviate significantly from open areas, depending on trees characteristics. This study aims to investigate the possible effect of small-scale factors on lichen growth forms in Mediterranean ecosystems. We sampled 70 plots in the western part of Sardinia (Italy). In each plot, proportionally to tree cover, one to six trees were randomly selected. Frequencies of corticolous lichen species were surveyed using a 10x50cm ladder, divided into five 10x10cm quadrats at each tree cardinal exposition. Therefore, we constructed a dataset by aggregating species according to their growth form. We collected a set of environmental variables for each tree, concerning both bark and canopy features. Climatic data obtained from CHELSA were downscaled to 10m resolution. Besides, precipitation data were modelled into throughfall and stemflow for each tree. Fourth corner analysis was used to disentangle the influences of microenvironmental variables on growth forms. We found that both bark and microclimatic factors are differently related to specific growth forms highlighting the importance of micro-scale factors in influencing lichen ecology. We stress the importance of taking into account small scale factors when investigating liches functional traits. Even in the same climatic area, the combination of phorophyte characteristics and topography can lead to different micro conditions experienced by lichens. For instance, in an arid climate such as Mediterranean, where water is a liming factor, a small difference in water availability, such as different water bark retention or stemflow, can determine differences in distribution of growth forms.
Complete tool for submission, evaluation and publication of proceedings for scientific events.
