Competition does not come at the expense of colonization in seed morphs with increased size and dispersal

• Autores: Miguel, María Florencia; Lortie, Christopher J.; Callaway, Ragan M.; Hierro, Jose Luis
• Año de publicación: 2017
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Anemochory; Bet-Hedging; Centaurea Solstitialis; Competition
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

PREMISE OF THE STUDY: Seed-level trade-offs of heterocarpic species remain poorly understood. We propose that seedlings emerging from seeds with apermanent pappus (dispersing seeds) are stronger competitors than those emerging from seeds without a pappus (nondispersing seeds) because dispersingseeds are larger and germinate faster than nondispersing seeds in Centaurea solstitialis .METHODS: We conducted a competition experiment with both seed morphs, in which we recorded emergence rate and proportion, estimated seed dispersalby wind (anemochory) and by mammals (exozoochory), and measured size and abundance of seed morphs.KEY RESULTS: We found that seedlings from pappus seeds had greater competitive abilities than those from non-pappus seeds. Similarly, pappus seedlingsemerged at much faster rates and larger proportions than non-pappus seedlings. Pappus seeds were larger, were more numerous, and displayed improvedexozoochory compared to non-pappus seeds. Anemochory was poor for both seed morphs.CONCLUSIONS: We found support for our hypothesis, raising in turn the possibility that competition and colonization are positively associated in seedmorphs of heterocarpic species with enhanced exozoochory of larger seeds. These fi ndings are not consistent with those from heterocarpic species withenhanced anemochory of smaller seeds or slower-germinating seeds. Our results additionally suggest that pappus and non-pappus seeds of C. solstitialisdisplay a task-division strategy in which pappus morphs colonize and preempt unoccupied sites through improved dispersal and fast and large emergenceof seedlings with increased competitive abilities, whereas non-pappus morphs promote site persistence through delayed germination and dormancy.This strategy may contribute to the success of C. solstitialis in highly variable environments.
Fil: Miguel, María Florencia. Universidad Nacional de la Pampa. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina
Fil: Lortie, Christopher J.. University of York; Reino Unido
Fil: Callaway, Ragan M.. University of Montana; Estados Unidos
Fil: Hierro, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina