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Effects of soil fungi, disturbance and propagule pressure on exotic plant recruitment and establishment at home and abroad
Author(s) -
Maron John L.,
Waller Lauren P.,
Hahn Min A.,
Diaconu Alecu,
Pal Robert W.,
MüllerSchärer Heinz,
Klironomos John N.,
Callaway Ragan M.
Publication year - 2013
Publication title -
journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.452
H-Index - 181
eISSN - 1365-2745
pISSN - 0022-0477
DOI - 10.1111/1365-2745.12108
Subject(s) - propagule , propagule pressure , seedling , biology , germination , invasive species , introduced species , native plant , fungicide , agronomy , plant community , botany , species richness , ecology , biological dispersal , population , demography , sociology
Summary Biogeographic experiments that test how multiple interacting factors influence exotic plant abundance in their home and recipient communities are remarkably rare. We examined the effects of soil fungi, disturbance and propagule pressure on seed germination, seedling recruitment and adult plant establishment of the invasive C entaurea stoebe in its native European and non‐native North A merican ranges. Centaurea stoebe can establish virtual monocultures in parts of its non‐native range, but occurs at far lower abundances where it is native. We conducted parallel experiments at four European and four Montana ( USA ) grassland sites with all factorial combinations of ± suppression of soil fungi, ±disturbance and low versus high knapweed propagule pressure [100 or 300 knapweed seeds per 0.3 m × 0.3 m plot (1000 or 3000 per m 2 )]. We also measured germination in buried bags containing locally collected knapweed seeds that were either treated or not with fungicide. Disturbance and propagule pressure increased knapweed recruitment and establishment, but did so similarly in both ranges. Treating plots with fungicides had no effect on recruitment or establishment in either range. However, we found: (i) greater seedling recruitment and plant establishment in undisturbed plots in Montana compared to undisturbed plots in Europe and (ii) substantially greater germination of seeds in bags buried in Montana compared to Europe. Also, across all treatments, total plant establishment was greater in Montana than in Europe. Synthesis . Our results highlight the importance of simultaneously examining processes that could influence invasion in both ranges. They indicate that under ‘background’ undisturbed conditions, knapweed recruits and establishes at greater abundance in Montana than in Europe. However, our results do not support the importance of soil fungi or local disturbances as mechanisms for knapweed's differential success in North America versus Europe.