02559nas a2200133 4500008004100000022001300041245006500054210006500119520210700184100002002291700002102311700002102332856007202353 2024 eng d a1439179100aCliffs support lichen communities unique from nearby forests0 aCliffs support lichen communities unique from nearby forests3 a
Cliffs support rare, endemic, and glacial relict vegetation that may differ from vegetation in surrounding forests. Yet, cliffs are difficult to sample, and rock-dwelling lichens can be challenging to identify; therefore, cliff lichens are often excluded from biodiversity studies. This omission creates fundamental gaps in our understanding of cliff lichens that lead to underestimation of overall community diversity. This study addresses one such gap by asking a basic question: do lichen communities on cliffs differ from rock-dwelling lichen communities in forests? To answer this question, we compared lichen communities from three cliffs in the Linville Gorge (North Carolina, USA; 369 m2 of cliff face surveyed) to rock and soil-dwelling lichen communities in forested plots across the same region (Southern Appalachian Mountains, USA, Alabama to North Carolina; 198 1-hectare forested plots). Forest plots were further divided into three groups based on elevation, proximity to Linville Gorge cliffs, and location within the state of North Carolina. A total of 225 rock or soil-dwelling lichen species were found in forest plots throughout the study area, while 104 species were found on cliffs. Two rare cliff-specialist species, Canoparmelia alabamensis, and Chrysothrix susquehannensis, were locally abundant on the studied cliffs but absent from surrounding forests. Our results show that cliffs support 20% of regional rock-dwelling lichen diversity, and that these cliff communities are distinct from those in forests. The high diversity, occurrence of unique species, and presence of rare lichens on cliffs indicate that cliff lichens should be included in biodiversity inventories and stewardship plans. To support this inclusion, we provide the first checklist for the lichens of Linville Gorge. Checklists like this one, including both cliff and non-cliff lichens, provide data on regional diversity and rarity that inform lichen conservation and rock climbing management.
1 aBoggess, L., M.1 aHarrison, G., R.1 aLendemer, J., C. uhttps://www.sciencedirect.com/science/article/pii/S143917912400086002386nas a2200193 4500008004100000022001300041245010700054210006900161260001600230300001100246490000800257520174400265100002002009700001902029700002702048700002002075700002102095856007602116 2024 eng d a0006320700aDisturbance and diversity: Lichen species richness decreases with increasing anthropogenic disturbance0 aDisturbance and diversity Lichen species richness decreases with cJan-05-2024 a1105980 v2933 a

Anthropogenic disturbance is rapidly increasing through habitat degradation, development, and deforestation. Gaps remain in understanding the effects of this disturbance on diverse and ecologically important organisms such as lichens. In North America, studies have focused on epiphytic macrolichens and catastrophic disturbance, largely ignoring microlichens and less severe disturbances. The Intermediate Disturbance Hypothesis predicts these moderate disturbances will lead to higher species richness. Here we examine the effects of anthropogenic disturbance in the form of land management on overall lichen richness, including microlichens, and on the species richness of eight lichen functional groups. The study draws on a comprehensive data set of 872 species, in 208 one-hectare plots throughout the Southern Appalachian Mountains, a global biodiversity hotspot in eastern North America. A habitat quality index based on an established forestry metric was used as a proxy for anthropogenic disturbance and was quantified using a 10-part score including categories such as percent native tree canopy cover and degree of fragmentation. Linear models were used to compare habitat quality scores to overall species richness and to species richness of functional groups. Rather than following the Intermediate Disturbance Hypothesis, all groups uniformly follow a negative linear relationship: as disturbance increases, species richness decreases. This pattern held even for widely variable functional groups such as morphotype. Effective conservation of lichen richness should prioritize the maintenance of existing older, less-disturbed stands within large, contiguously forested areas.

1 aBoggess, L., M.1 aMcCain, C., M.1 aManzitto-Tripp, E., A.1 aPearson, S., M.1 aLendemer, J., C. uhttps://www.sciencedirect.com/science/article/abs/pii/S0006320724001605