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International Journal of Ecology
Volume 2016, Article ID 7614683, 10 pages
http://dx.doi.org/10.1155/2016/7614683
Research Article

Potential Germination Success of Exotic and Native Trees Coexisting in Central Spain Riparian Forests

Departamento de Ciencias de la Vida, Unidad Docente de Ecología, Facultad de Ciencias, Universidad de Alcalá, N-II, Km 33.6, P.O. Box 20, Alcalá de Henares, 28805 Madrid, Spain

Received 18 October 2015; Accepted 15 March 2016

Academic Editor: L. M. Chu

Copyright © 2016 Isabel Cabra-Rivas and Pilar Castro-Díez. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We compared potential germination success (i.e., percentage of produced seeds that germinate under optimal conditions), the percentage of empty and insect-damaged seeds, germinability (), and time to germination () between the exotics Ailanthus altissima, Robinia pseudoacacia, and Ulmus pumila and two coexisting native trees (Fraxinus angustifolia and Ulmus minor) in the riparian forests of Central Spain. Additionally, we tested the effect of seed age, seed bank type (canopy or soil) and population on and of A. altissima and R. pseudoacacia, which are seed-banking species. Species ranked by their potential germination success were A. altissima > U. pumila > R. pseudoacacia > U. minor > F. angustifolia. The combination of a high and negligible seed insect-damage provided A. altissima with a potential germination advantage over the natives, which were the least successful due to an extremely high percentage of empty seeds or a very low . R. pseudoacacia showed high vulnerability to insect seed predation which might be compensated with the maintenance of persistent seed banks with high . and were strongly affected by seed age in the seed-banking invaders, but between-seed bank variation of and did not show a consistent pattern across species and populations.