Dynamics of a Neotropical Forest: The First Decade

新热带森林的动态：第一个十年

• 批准号: 8906869
• 负责人: Stephen Hubbell
• 金额: $ 21万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-01-01 至 1992-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8906869&HistoricalAwards=false
• 关键词: Dynamics; Neotropical; Forest; First; Decade

In spite of recent progress, the composition, structure and dynamics of species-rich tropical forests, and the demography of tropical trees, remain largely unknown. Few long-term studies of such tropical forests exist that have population samples adequate for life history analyses of individual tree species, or for community-level analyses. This research will monitor the fate (growth, survival, and recuitement) of over a quarter of a million individuallly tagged, mapped, and identified trees, saplings, and shrubs of 306 species in a 50 ha permanent forest plot on Barro Colorado Island, Panama. Two censuses of the plot have been completed, the first between 1980 and 1982, and the second in 1985. This 1990 recensus is particularly important for a number of reasons. During the first census interval, the worst drought in more than 60 years occurred in central Panama, causing heavy mortality in many tree species in the plot as well as shifts in relative species abundance. No comparable drought has occurred during this census interval. Thus it will be possible to assess the community-level effects of a major episodic climatic event on longer-term patterns of tree mortality, growth, and recuitment. The recensus will also reveal whether the direction of population change for each species has remained consistent over the past decade. It will also enable an improved analyses of tree growth and survival measures current performance of each tree as a function of not only of its current local biotic and physical environment but also as a function of its past performance and recent environmental history. For the first time, the extent to which individual tree growth rates are temporally autocorrelated can be tested. According to one hypothesis, only the fastest growing individuals survive to reach the canopy. If this is true, then canopy adults may be much younger than ages estimated from averaged and randomized size- specific growth rates in the population--the usual projection metnods. Finally, but not least, the recensus results are needed because the present plot data, which are used by a sizeable number of scientists, are no longer accurate. Based on preliminary stem counts, it is estimated that the plot has already experienced about 10-12% total turnover in plants with diameters greater than one centimeter.

尽管最近取得了进展，但物种丰富的热带森林的组成、结构和动态以及热带树木的人口统计在很大程度上仍然未知。 对此类热带森林的长期研究很少有足够的种群样本来进行单个树种的生活史分析或群落层面的分析。 这项研究将监测巴拿马巴罗科罗拉多岛 50 公顷永久林地中超过 25 万棵经过单独标记、绘制和识别的 306 种树木、树苗和灌木的命运（生长、生存和恢复）。 该地块的两次人口普查已经完成，第一次是 1980 年至 1982 年，第二次是 1985 年。由于多种原因，1990 年的普查尤为重要。 在第一次人口普查期间，巴拿马中部发生了 60 多年来最严重的干旱，导致该地区许多树种大量死亡，以及相对物种丰度的变化。 本次人口普查期间没有发生类似的干旱。 因此，将有可能评估重大偶发性气候事件对树木死亡率、生长和补充的长期模式的群落影响。 普查还将揭示过去十年中每个物种的种群变化方向是否保持一致。 它还将能够改进对树木生长和生存的分析，衡量每棵树的当前性能，不仅是其当前当地生物和物理环境的函数，而且是其过去性能和近期环境历史的函数。 第一次可以测试单棵树生长率在时间上自相关的程度。 根据一种假设，只有生长最快的个体才能存活下来到达树冠。 如果这是真的，那么树冠成虫的年龄可能比根据种群平均和随机大小特定增长率（通常的预测方法）估计的年龄要年轻得多。 最后但并非最不重要的一点是，需要普查结果，因为目前大量科学家使用的绘图数据不再准确。 根据初步的茎计数，估计该地块直径大于 1 厘米的植物总周转率已达到约 10-12%。