The Dynamics of a Neotropical Forest: The Year 2000 Recensus

9909947哈贝尔巴罗科罗拉多岛(BCI)森林动力学项目是世界上运行时间最长的大规模热带森林研究，旨在测试种群和整个社区层面上相互竞争的理论，以维持热带潮湿森林中的高度树木物种多样性。BCI研究是自1980年以来在新旧世界热带建立的类似地块全球网络的旗舰项目和模式。目前的活动是在2000年对BCI上的50公顷土地进行第五次全面普查，将研究延长到20年。第五次普查的目标是(1)更新自5年前上次普查以来样地中所有木本植物1厘米胸径(240,000株)的招募、生长和存活的数据，(2)将普查扩展到较小的幼树大小类别；(3)分析所有树木的命运(生长、存活)作为其当地生物邻居的函数；(4)利用邻域分析和其他信息来开发BCI森林的第一代动态模型。了解这些局部邻域效应对于开发冠层树木替换的预测理论至关重要，而这反过来又对于理解树种多样性是如何在BCI森林中保持的至关重要。通过上一次人口普查，对23万株植物13年存活率的初步邻里分析已经完成。对局部植物的存活有显著的、通常是强烈的邻里效应。分析了4个邻域因素的影响：与焦点植物相同物种的邻居数、从第一次到最后一次不考虑物种的邻域数、焦点植物相对于其邻域的大小以及焦点植物邻域中的物种数。这些结果如果得到下一次人口普查的补充数据的证实，将对理解导致热带森林群落树种多样性高的因素具有重要意义。

9909947HubbellThe Barro Colorado Island (BCI) Forest Dynamics Project is the longest running large-scale study in the world of a tropical forest, established to test competing theories at the population and whole community level for the maintenance of high tree species diversity in tropical moist forests. The BCI study is the flagship project and model for a global network of similar plots established since 1980 throughout the New and Old World tropics. Current activities are to conduct the fifth complete census of the 50 ha plot on BCI in the year 2000, extending the study to two decades. The goals of the fifth census are (1) to update the data on recruitment, growth, and survival of all woody plants 1 cm dbh (240,000 stems) in the plot since the last census 5 years ago, (2) to extend the census to smaller sapling size classes; (3) to analyze the fate of all trees (growth, survival) as a function of their local biotic neighborhood, and (4) to use this neighborhood analysis and other information to develop a first-generation dynamical model of the BCI forest. Understanding these local neighborhood effects is essential for developing a predictive theory of canopy tree replacement, which in turn is critical for understanding how tree species diversity is maintained in the BCI forest. A preliminary neighborhood analyses on the 13-year survival of 230,000 individual plants through the last census has been completed. There were significant, often strong, neighborhood effects on focal plant survival. The effects of four neighborhood factors were analyzed: the number of neighbors of the same species as the focal plant, the number of neighbors surviving from the first to the last census irrespective of species, the size of the focal plant relative to its neighbors, and the number of species among the focal plant's neighbors. The results, if borne out by additional data from the next census have important implications for understanding the factors that lead to high tree species diversity in tropical forest communities.