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Fine‐scale distribution and abundance of epiphytic lichens: environmental filtering or local dispersal dynamics?
Author(s) -
Schei Fride Høistad,
Blom Hans H.,
Gjerde Ivar,
Grytnes JohnArvid,
Heegaard Einar,
Sætersdal Magne
Publication year - 2012
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/j.1654-1103.2011.01368.x
Subject(s) - biological dispersal , lichen , epiphyte , abundance (ecology) , ecology , relative species abundance , spatial ecology , species distribution , spatial distribution , biology , geography , habitat , population , demography , remote sensing , sociology
Questions How are the fine‐scale spatial distribution and abundance of epiphytic lichens explained by factors related to environmental filtering and local dispersal? Are spatial distribution and abundance explained by the same underlying factors across sites for: (1) each species separately; or (2) groups of species with similar dispersal strategies? Location Ten lowland deciduous forests at the southwest coast of N orway (60ºN, 5ºE). Methods We investigated the spatial distribution and abundance, given occurrence, of 15 epiphytic L obarion lichens in ten forest sites: six 1800‐m 2 study sites and four 5000‐m 2 study sites. We divided each site into a grid of 1‐m 2 sampling units, marked all trees and recorded the abundance of individual lichen species. We assessed the relative impact of factors related to environmental filtering and local dispersal for each lichen species using multiple regressions and variation partitioning. Finally, to compare the results between species and between sites, we applied linear mixed effect models. Results We found that the occurrence of lichen species on a tree is explained primarily by factors related to environmental filtering. The abundance of lichen species that occur on a tree is explained by a combination of environmental filtering and local dispersal, but the relative importance of these factors was found to vary greatly between sites. We found no differences in this respect between species with different dispersal strategies. Conclusions Our results indicate that both environmental filtering and local dispersal dynamics are important processes explaining the distribution and abundance patterns of Lobarion lichens at fine spatial scales. However, spatial variations in environmental factors within sites interact with propagule distributions to produce a range of inter‐site variation. Accordingly, the relative importance of these two structuring mechanisms varies among sites, particularly in the case of abundance patterns. Since single‐site patterns are not readily generalized, we emphasize the importance of multiple study sites for evaluation of the role of different processes in shaping the spatial distribution patterns of species.