| Chinese yew (Taxus chinensis var. mairei), one of the relict plants in Tertiary Period, wasrated as national first-class protective species. There is a Chinese yew population of hundreds oftrees, which has old age of stand, being relatively densely and continuously distributed inEcological Garden of Yew, Fujian Meihuashan National Natral Reserve. Our research has beendone in the garden from September to November in2011and from October to December in2012respectively. We measured the seed rain, seed bank, regeneration of Chinese yew population, andespecially the impact of furgivorous animals on seed fate and recruitment. Our results showed asfollows:1. Seed trees of Chinese yew began to bear fruits at the end of September, and graduallymatured from the end of October. Full bearing age appeared in the middle of November, and fruitdropping decreased to stability in December. The seed rain continued for a lot of days, amongwhich the peak period lasts for21days. Due to the different mature periods of twigs and therainfall, the curve line of seed rain revealed a fluctuation state with low ends, high medium, andmultiple peaks. The seed rain consisted of5types: mature and complete fruit, immature fruit,gnawed fruit, thrown up bare seeds, and molded fruit. The quality of seed rain was fairly high,and there were more than half of the seeds that can keep mature and complete. Gnawed fruitdensity in seed rain of different forest types is: broadleaved forest＞bamboo-broadleaved-mixedforest＞bamboo forest; thrown up seeds density was the same as above.2. According to samples of soil seed banks of three different forest types taken in earlier andlater stage of seed rain in2012, there were immature, mature and gnawed seeds in seed bank.Meanwhile, the number of complete seeds in soil seed bank of three forest types had a significantgrowth after the peak period of seed rain. The increment of complete seeds density was: bambooforest (321.3±55.55)seeds/m2，bamboo-broadleaved-mixedforest (192.5±50.4)seeds/m2，broadleaved forest (288.8±52.7)seeds/m2. We can see from horizontal distribution ofseed bank that seeds mostly distributed under crown of the seed trees and dispersed away fromthe crown. In the course of seed rain entering into seed bank, the seed loss was mainly due to thefeeding of ground animals. In different types of forest, the density of mature and complete seedsin the seed bank appeared as: bamboo forest＞bamboo-broadleaved-mixed forest＞broadleavedforest; and the density of gnawed seeds appeared as: broadleaved forest＞bamboo forest＞bamboo-broadleaved-mixedforest.3. There were totally35animal species feeding on Chinese yew fruit during our observationperiod. According to cluster analysis (furthest neighbor) which based on feeding behavior,feeding position and feeding substrate, all these35species of animals can be divided into3guilds on the level of=25or9guilds on the level of=15. Besides, these animals can bedivided into three groups, which are ants (4types), rodents (5types) and birds (26types). Ants had only little impact on the dispersion of Chinese yew. Rodents were the main consumers ofseeds, while rats may also have some caching dispersal function. The removal experimentshowed that the intensity of rats feeding was: bamboo forest＞bamboo-broadleaved-mixed forest＞broadleaved forest. Birds were the main fruit/seeds predators and dispersers. In both2011and2012, black bulbul (Hypsipetes leucocephalus) was the main predator, with more than60%of thetotal feeding frequency each year. Those7birds which swallowed the whole fruit and dispersedthe seeds all belong to Pycnonotidae and Corvidae. Corvidae swallowed more fruit once, flew arather longer distance and carried seeds for much longer time, thus defecating intact seeds awayfrom parent trees through the end of gut. Meanwhile, Pycnonotidae swallowed less, flew shorterand throw up the seeds soon after consumed the pulp. So they carried seeds for shorter time anddistance. Those two bird families help Chinese yew disperse and regenerate from different layers.4. This Chinese yew population was mainly composed of seedlings (70.11%) and growntrees (20.11%), while saplings was rather rare. In spatial distribution, seedlings had a contagiousdistribution, while grown trees distributed more evenly. From a full view of survival rates ofseedlings and saplings, the finding were as follows: the bamboo-broadleaved-mixed forest on theboundary showed the best regeneration of the Chinese yew; bamboo forest was suitable for seedgermination and the early growth of seedlings, but it had more disadvantages on seed ecesis andformation of saplings; broadleaved forest obtained the most dispersed seeds, however, the overallregeneration of Chinese yew here was rather poor, except for those in the gaps. Seeds dispersal offrugivorous animals played an undispensable role in current distribution of regeneratingpopulation. |
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