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Primary succession, disturbance and productivity drive complex species richness patterns on land uplift beaches
Author(s) -
Nylén Tua,
Luoto Miska
Publication year - 2015
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.1111/jvs.12232
Subject(s) - species richness , ecological succession , ecology , generalist and specialist species , primary succession , productivity , disturbance (geology) , intermediate disturbance hypothesis , geography , biology , habitat , paleontology , economics , macroeconomics
Questions What are the interactive effects of succession time, disturbance and productivity on the fine‐scale species richness of beach vegetation? How do these effects differ between functional groups that are known to represent different adaptive strategies? Location Boreal beach and dune systems (ca. 60°–65° N) of the Baltic Sea coast in Finland, characterized by steep environmental gradients, post‐glacial land uplift and resulting primary succession. Methods The analysis was based on an extensive and systematic survey of vascular plant, bryophyte and lichen species and environmental factors. Total species richness and the species richness of seven functional groups were modelled as functions of succession time, disturbance, productivity and their statistical interactions. The effects of the local environmental variability were taken into account by applying generalized linear mixed models ( GLMM ). Results All three environmental factors and their statistical interactions, including the three‐way interaction, were highly significant in explaining total species richness. The effect of disturbance on total species richness changed from negative to positive along succession time and productivity gradients. The response of beach specialist richness to succession time and disturbance was unimodal, while the responses of the generalist functional groups were monotonic. Beach specialist richness showed a strong positive response to productivity, whereas the richness of the generalist groups was not related to changes in productivity. Conclusions The patterns of species richness on uplifting beaches are determined by the interplay of primary succession, disturbance and productivity. When both succession time and productivity increase, competitive exclusion starts to limit total species richness. In these circumstances, disturbance favours diversity by creating gaps in the vegetation. A combination of long succession time, low disturbance and low productivity result in maximum species richness. The richness of functional groups, particularly the opportunistic and disturbance‐tolerant beach specialist group and the competitive but disturbance‐sensitive groups, reach their peak in divergent environmental conditions. Consequently, the complex richness patterns observed on uplifting beaches are created not only by strongly interacting environmental drivers but also by differences in species' adaptive strategies.