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SPATIAL AND TEMPORAL PATTERNS OF SEED DISPERSAL: AN IMPORTANT DETERMINANT OF GRASSLAND INVASION
Author(s) -
DiVittorio Christopher T.,
Corbin Jeffrey D.,
D'Antonio Carla M.
Publication year - 2007
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1890/06-0610
Subject(s) - propagule , biological dispersal , introduced species , biology , seed dispersal , grassland , ecology , invasive species , propagule pressure , colonization , native plant , competition (biology) , spatial ecology , seedling , interspecific competition , agronomy , population , demography , sociology
We measured spatial and temporal patterns of seed dispersal and seedling recruitment for 58 species in a grassland community to test whether seed dispersal could predict patterns of invasion after disturbance. For the 12 most abundant grasses, recruitment of native species was dependent on the propagule supply of both native and exotic species. Variability in seed rain on small spatial (1 – 10 m) and temporal (within season) scales led to qualitative differences in the outcome of disturbance colonization such that native species dominated disturbances when exotic seed supply was low but failed to establish when exotic seed supply was high. Local dispersal and spatial heterogeneity in species composition promoted coexistence of native and exotic species by creating refuges from high exotic seed supply within native dominated patches. Despite this, copious exotic seed production strongly limited recruitment of native species in exotic dominated patches. Most grasslands in California are presently dominated by exotic species, suggesting that competition at the seedling stage is a major barrier to native species restoration.