Sexual Systems and Ecological Correlates in an Azonal Tropical Forests, SW China
Article first published online: 17 OCT 2007
2008 The Author(s) Journal compilation © 2008 by The Association for Tropical Biology and Conservation
Volume 40, Issue 2, pages 160–167, March 2008
How to Cite
Chen, X.-S. and Li, Q.-J. (2008), Sexual Systems and Ecological Correlates in an Azonal Tropical Forests, SW China. Biotropica, 40: 160–167. doi: 10.1111/j.1744-7429.2007.00364.x
- Issue published online: 17 OCT 2007
- Article first published online: 17 OCT 2007
- Received 24 October 2006; revision accepted 9 July 2007.
- flower sizes;
- fruit types;
- montane forest;
- seasonal forest
Unlike the seriate lowland rain forests in SE Asia, the tropical vegetation of Xishuangbanna (SW China) has developed in habitats with comparatively lower temperatures and precipitation. Consequently, although most of the families and genera of the flora are components of tropical ecosystems, many have reached their distribution limits in latitude. Selection pressures on sexual systems in these environments may be different from that experienced in lowland tropical regions. Here, we examine the sexual systems of 685 species of flowering plants belonging to 109 families and 356 genera based on 42 plots with a total area of 15.4 ha and compare our results with surveys of sexual systems from other tropical ecosystems. Among these species, 60.6 percent were hermaphroditic, 14.3 percent were monoecious, and 25.1 percent were dioecious. The percentage of dioecious sexual system among tree species (26.1%) was similar or higher than that of other tropical tree floras. Monoecy was significantly associated with the tree growth form and was relatively common in seasonal forest vegetation. Sexual systems involving unisexual flowers (dicliny) are particularly well represented in the tropical forests of Xishuangbanna accounting for 39.4 percent of all species surveyed. This pattern may be associated with the prevalence of relatively small inconspicuous flowers in the tropical forests of SE Asia and their correlation with diclinous sexual systems generally.