The enhancement of invasion ability of an annual grass by its fungal endophyte depends on recipient community structure
Most terrestrial plants establish symbiotic associations with microorganisms that enable them to overcome abiotic or biotic filters in ecosystems. Here we investigated how aerial mutualisms involving invasive species may affect the recipient community's structure. We hypothesized that the endophyte Epichloe occultans enhances the ability of Lolium multiflorum to establish and colonize, but that success would depend on the structure and invasion resistance of the recipient grassland community. Seeds of L. multiflorum with high [E?] and low [E-] endophyte incidence were sown in plots located in grasslands with or without recent grazing history. Relative cover of L. multiflorum and floristic groups was determined during the growing season. Whereas we did not detect any endophyte effect in sites with grazing history, L. multiflorum cover was 63 per cent in E? and 27 per cent in Eplots in sites without grazing history. As cover of L. multiflorum increased in these sites, the cover of warm- and cool-season grasses decreased in spring, with that of warm-season grasses continuing to decrease in summer. These decreases corresponded to 1.9, 3.7 and 1.6 per cent, for every per cent increase of L. multiflorum cover. Path analysis and posterior modelling predicted a greater impact of the endophyte on L. multiflorum cover than of seed addition when resident L. multiflorum cover was B20 per cent. This effect decreased asymptotically as L. multiflorum cover increased beyond 20 per cent. Our results suggest that the endophyte may boost the invasion ability of L. multiflorum particularly in natural grassland without grazing history with potential longer-term consequences for community structure and dynamics.
| Main Authors: | , , , , |
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| Format: | Texto biblioteca |
| Language: | eng |
| Subjects: | LOLIUM MULTIFLORUM, EPICHLOE OCCULTANS, GRASS ENDOPHYTE SYMBIOSIS, GRASSLAND FUNCTIONAL GROUPS, , |
| Online Access: | http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=47330 http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= |
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| Summary: | Most terrestrial plants establish symbiotic associations with microorganisms that enable them to overcome abiotic or biotic filters in ecosystems. Here we investigated how aerial mutualisms involving invasive species may affect the recipient community's structure. We hypothesized that the endophyte Epichloe occultans enhances the ability of Lolium multiflorum to establish and colonize, but that success would depend on the structure and invasion resistance of the recipient grassland community. Seeds of L. multiflorum with high [E?] and low [E-] endophyte incidence were sown in plots located in grasslands with or without recent grazing history. Relative cover of L. multiflorum and floristic groups was determined during the growing season. Whereas we did not detect any endophyte effect in sites with grazing history, L. multiflorum cover was 63 per cent in E? and 27 per cent in Eplots in sites without grazing history. As cover of L. multiflorum increased in these sites, the cover of warm- and cool-season grasses decreased in spring, with that of warm-season grasses continuing to decrease in summer. These decreases corresponded to 1.9, 3.7 and 1.6 per cent, for every per cent increase of L. multiflorum cover. Path analysis and posterior modelling predicted a greater impact of the endophyte on L. multiflorum cover than of seed addition when resident L. multiflorum cover was B20 per cent. This effect decreased asymptotically as L. multiflorum cover increased beyond 20 per cent. Our results suggest that the endophyte may boost the invasion ability of L. multiflorum particularly in natural grassland without grazing history with potential longer-term consequences for community structure and dynamics. |
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