Assembly patterns of soil‐dwelling lichens after glacier retreat in the European Alps

Abstract

AimTo assess the spatial‐temporal dynamics of primary succession following deglaciation in soil‐dwelling lichen communities.LocationEuropean Alps (Austria, Switzerland and Italy).MethodsFive glacier forelands subjected to relevant glacier retreat during the last century were investigated. In each glacier foreland, three successional stages were selected at increasing distance from the glacier, corresponding to a gradient of time since deglaciation between 25 and 160 years. In each successional stage, soil‐dwelling lichens were surveyed within five 1 × 1 m plots. In addition to a classical ecological framework, based on species richness and composition, we applied a functional approach to better elucidate community assembly mechanisms.ResultsA positive relationship was found between species richness and time since deglaciation indicating that richer lichen communities can be found at increasing terrain ageing. This pattern was associated with compositional shifts, suggesting that different community assemblages can be found along the successional stages. The analysis of β‐diversity revealed a significant nested pattern of species assemblages along the gradient (i.e. earlier successional stages hosted a subset of the species already established in older successional stages), while the turnover component was less relevant. Considering functional groups, we found contrasting patterns in relation to time since deglaciation: the incidence of species with a cyanobacterial photobiont and those reproducing by spores decreased, while that of species reproducing by vegetative propagules increased.Main conclusionsThis study reveals that community assembly patterns of soil‐dwelling lichens in alpine glacier forelands are ruled by mechanisms of directional species accumulation and trait selection that involve a trade‐off between different functional strategies. Functional traits that reflect the dispersal and adaptation capability of the species underpin the colonization success of soil‐dwelling lichens in glacier forelands.

Symbiosis between river and dry lands: phycobiont dynamics on river gravel bars

“…The species richness of terricolous lichens on glacier forelands in Alps were positively correlated with time since deglaciation (Nascimbene et al 2017) analogically to lichen species richness on deglaciated plots in maritime Antarctica (Favero-Longo et al 2012). In both cases, most of species, once established, persisted to the oldest successional stages.…”

When and where does dispersal limitation matter in primary succession?

“…Similarly, dispersal limitation in glacier forelands was assessed in relatively few areas, mainly in Europe (e.g. Buma, Bisbing, Krapek, & Wright, ; Makoto & Wilson, ; Nascimbene, Mayrhofer, Dainese, & Bilovitz, ) and North America (e.g. Fastie, ; Jones & del Moral, ).…”

Effects of a tropical cyclone on salt marsh insect communities and post‐cyclone reassembly processes

“…For instance, replacement sequences constitute a core prediction in traditional successional models wherein ‘early’ colonizers communities are replaced by competitively‐dominant ‘late’ colonizers (Connell and Slatyer , Lichter , Platt and Connell ). In contrast, community nestedness occurs when 1) early colonizers remain in the system and early communities are subsets of later ones (Nascimbene et al , Woods ), or 2) all species are present post‐disturbance and groups of species disappear in orderly sequences over time (Initial Floristic Composition, Egler , Imbert ). Alternatively, assemblage dynamics post‐disturbance can be determined mainly by abundance differences rather than species composition changes, resulting in neither replacement nor nestedness patterns (Schowalter and Ganio , Carnicer et al , Novais et al ).…”