碩士 / 東海大學 / 生物學系 / 87 / There are many factors influencing the recruitment of a plant population. These include biotic factors, such as behavior of seed dispersal agents, disease or herbivores, and abiotic factors, such as environmental conditions and disturbance. The purpose of this study is to investigate the effects of seed dispersal agents on seed germination and seedling survival rates of Diospyros discolor Willd. The study site is located in Kenting high coral reef forest nature reserve. Macaca cyclopis is the main seed dispersal agents for D. discolor in this forest. Through macaque's frugivorous and social behavior, seeds will be either spitted out singly, drop altogether in clump underneath parent trees or drop intact underneath parent trees. Moreover, seeds can be carried through the forest and dropped in different habitats, such as gaps or mature forest floor and with different distances from the parent trees. My study was organized around the following questions: (1) Are there any differences in seed germination rate and seedling survival rate between different types of seeds caused by M. cyclopis? (2) Are there any differences in seed germination rate and seedling survival rate in different environments? (3) Are there any advantages for seeds being away from their parent trees?
To investigate the effects of M. cyclopis and different environmental conditions on the recruitment of D. discolor, I established twelve 1 x 1 m plots in three different habitats: gap, mature gap and closed canopy. Each plot contains four types of seeds (two types of single seed, clumped seeds and intact fruit) that were collected during the 1997 fruiting season. Germination rates and seedling survival rates were monitored monthly from September 1997 to September 1998. At the same time, seeds and seedlings survival in natural forest were investigated for compared with experimental treatment. The results showed that germination rates were lowest in gap than that of mature gap and closed canopy habitats. Seedling survival rates did not show significant difference between gap, mature gap and closed canopy. In addition, seedling growth rates in gap and mature gap were significantly higher than that of closed canopy. Seedling survival rates of single seed were significantly lower than that of intact fruits and clumped seeds in the experimental treatment. But in natural forest, survival rate of single seed were higher than intact fruits.
To test the relationships between seedling survival rates and the distance from their parent trees, four female trees where their nearest conspecific neighbors were at least 15 meters away were selected in February 1997. All seedlings of 1996 and 1997 cohort of these four trees were tagged, and height of seedlings, number of leaves and seedling survival were monitored monthly from February 1997 to February 1999. The results showed that there was no difference in seedling survival rates between seedlings under the canopy of parent trees and seedlings away from parent trees. This fact did not support Janzen-Connell hypothesis. This indirectly indicates that M. cyclopis may only play a minimum role in the recruitment of D. discolor.
| Identifer | oai:union.ndltd.org:TW/087THU00112003 |
| Date | January 1999 |
| Creators | Yu-Wen Pan, 潘郁雯 |
| Contributors | I-Fang Sun, 孫義方 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 54 |
Page generated in 0.0022 seconds