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Differential effects of dominant and subordinate plant species on the establishment success of target species in a grassland restoration experiment
Author(s) -
Torrez Vania,
Mergeay Joachim,
Meester Luc De,
Honnay Olivier,
Helsen Kenny
Publication year - 2017
Publication title -
applied vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.096
H-Index - 64
eISSN - 1654-109X
pISSN - 1402-2001
DOI - 10.1111/avsc.12302
Subject(s) - species richness , generalist and specialist species , biology , ecology , forb , grassland , species evenness , species diversity , niche , niche differentiation , plant community , habitat
Questions We investigated how the establishment of sown target species for ecological restoration is affected by the early introduction of either dominant or subordinate species during the assembly of a restored topsoil‐stripped, nutrient‐poor grassland. Do dominant or subordinate species exert different priority effects on either wanted target species or unwanted pioneer species? If priority effects are detected, are these exerted via niche preemption or niche modification mechanisms? Are the resulting patterns of species establishment related to differences in functional trait composition? Location Meerdaal forest, Oud‐Heverlee, Belgium. Methods A 2‐yr field experiment on a topsoil‐stripped site of 8.5 ha was carried out. We manipulated the early arrival of dominant and subordinate species. The ‘dominant species’ set consisted of three generalist grass species, and the ‘subordinate species’ set consisted of nine species of forbs and graminoids that often occur in nutrient‐poor grasslands. After 4 wk, we sowed nine target species for ecological restoration. We recorded plant species cover during 2 yr. We used repeated measures ANOVA to test for effects of time (2013, 2014) and treatment ( dominant , subordinate and control) on plant species richness, evenness, cover, functional diversity and species and trait composition dissimilarity. Results Both dominant and subordinate species successfully suppressed undesirable early colonizing species. Dominants did not exert priority effects on target species. However, subordinate species exerted strong priority effects via niche preemption, and suppressed their establishment of target species. Conclusions Manipulating the arrival order of dominant species has potential as a restoration tool that can allow restoration practitioners to enhance the establishment success of target species for restoration. We suggest that seed mixtures for restoration should contain dominant species, because they will not affect the establishment of subordinate (target) species, but will impede the establishment of unwanted pioneer and ruderal species. We also demonstrate that implementing trait‐based measures in restoration projects can help to adequately predict assembly processes.