Figure 1.
Fruits, seeds, and seedlings of Syzygium mamillatum.
(A) Developing fruits on the lower ∼50 cm of a Syzygium mamillatum tree. (B) Ripe fruits attached to the trunk. Note the foremost fruit has split open, releasing a fermented smell. (C) A ‘ball’ of four seeds from one fruit with the pulp removed. (D) Germinating seed. Note the clear line between the two green cotyledons. (E) Giant Aldabra tortoise feeding on S. mamillatum fruits. (F) Seeds with and without the slimy, fibrous endocarp. (G) Seed fragments after tortoise gut-passage. Fragments were most often found as whole cotyledons. Note how some cotyledons are still green on the side that faced the other cotyledon, suggesting that they did not break apart until late in the passage. (H) A caged patch of seeds. (I) An experimental patch of seedlings.
Figure 2.
Gut-passage patterns of seeds and seed fragments of Syzygium mamillatum fruits fed to Aldabra tortoises.
The two arrows indicate the beginning and the end of the feeding period, respectively.
Figure 3.
Seed germination patterns of Syzygium mamillatum.
(A)–(D) illustrates the interactions with Time for each of the main effects (see Table 1). Values plotted are means±1 SE at the maternal tree level (N = 20 trees, except for plateau which a sample size of 15 maternal trees on the lower plateau, and 5 maternal trees on the upper plateau). In (C), we have added the germination pattern of tortoise gut-passed seeds (overall proportion, seeds and seedlings pooled from all 12 gut-passed seed plots). (E) Illustrates the significant interaction from Table 1.
Table 1.
Syzygium mamillatum seed germination patterns.
Figure 4.
Percentage of tortoise gut-passed seeds germinating in relation to faeces collection week.
Numbers above the bars are the number of seeds sown in the forest on the upper and lower plateau, respectively.
Figure 5.
Seedling damage levels recorded in the first seedling damage survey in January 2005.
The damage is expressed as proportions of total number of leaves per seedling suffering from the seven individual damage classes: ‘leaf mine’, ‘fungus’, ‘curled leaf’, ‘bite damage’, necrosis’, ‘scale insect’, and ‘discolouration’; ‘total’ means all seven damage classes pooled at the seedling level; ‘diversity’ means how many types of damage a seedling suffers from in proportion out of seven. Significant differences between close and away, and between away and gut-passed are marked above the corresponding pairs of bars (P<0.10; * P<0.05; ** P<0.005; see Table 2). All values for close and away seedlings are means±1 SE at the maternal tree level (N = 20 trees), values for seedlings from gut-passed seeds are means of the seven plots where seedlings emerged.
Table 2.
First seedling damage survey.
Table 3.
Seedling survival from 2004 to 2006.