Bryophyte and macrolichen diversity show contrasting elevation relationships and are negatively affected by disturbances in laurel forests of Madeira island

Abstract

Questions Studies on bryophyte and lichen diversity patterns along elevational gradients are scarce, although this approach can serve as space‐for‐time substitution to predict diversity changes because of climate warming. Therefore, we investigated bryophytes and macrolichens in disturbed and undisturbed stands along an elevational gradient in the unique laurel forest of Madeira island by addressing the following questions: (a) how does the species richness of functional‐taxonomic bryophyte and macrolichen groups differ with elevation; (b) how is the species richness of these groups affected by disturbances? Location UNESCO World Natural Heritage site laurel forest of Madeira island (Madeira, Portugal). Methods We analyzed species richness of bryophytes and macrolichens in 92 plots in response to elevation and to disturbances. Results Bryophyte species richness showed a mid‐elevational peak, while macrolichen richness increased with elevation. Disturbed plots harbored on average 20% less bryophyte and macrolichen species than undisturbed plots. Conclusions The laurel forest of Madeira island is a bryophyte and lichen diversity hotspot. Our findings indicate future biodiversity threats by changing environmental conditions. This calls for the need for a strict protection status of the laurel forest on Madeira island to minimize human‐related disturbances, for the development of management measures that could mitigate climate change effects by maximizing habitat suitability and for the implementation of species conservation programs to prevent future extinctions, in particular of endemic species.

Direct and Indirect Effects of Management Intensity and Environmental Factors on the Functional Diversity of Lichens in Central European Forests

“…In addition, the older stands with low management intensity were mostly dominated by European beech, which is characterized by a dense canopy cover and low light conditions [ 44 , 87 ]. These particular environmental conditions might promote a certain set of functional entities of lichens (e.g., mainly crustose species, species with low light EIV, lichen species with Trentepohlia algae and cyanobacteria, or a particular set of secondary metabolites [ 64 , 92 , 93 , 94 ]), resulting in a lower functional diversity of lichens. This corresponds well with our findings of enhanced functional diversity of adaptation-related traits (FDisAd) with higher forest management intensity.…”

Integrating dark diversity and functional traits to enhance nature conservation of epiphytic lichens: a case study from Northern Italy

“…Although crustose species are considered drought tolerant, their higher proportion in dark diversity at low elevations suggests that some establishment limitation occurs at those elevations, hampering some species of this group to thrive at warmer conditions. On the other hand, macrolichen species are expected to be highly threatened under climate change, either because they are more sensitive to warming (Boch et al 2019) or due to their low proportion in dark diversity. This low stress-tolerance and low proportion in dark diversity indicates that local losses of macrolichens will likely represent species pool losses (i.e.…”

Island biogeography: an avenue for research in bryology

“…due to their geographic isolation, volcanic origin and elevation range, oceanic islands offer an ideal setting for disentangle the contribution of environmental and historical factors to diversity patterns (Q1). In bryophytes, a humpshape relationship between alpha diversity and elevation has been consistently reported (Henriques et al 2017a, Boch et al 2019, Hernández-Hernández et al 2019, Marline et al 2020 and interpreted in terms of the optimal climatic conditions that prevail at mid-elevation for bryophytes. among other components of diversity, functional diversity has increasingly appeared as a complementary metric to taxonomic diversity (Spitale 2016, Øien et al 2018, Berdugo & dovciak 2019.…”