The Dynamics of a Neotropical Forest: The Year 2000 Recensus

[909947] hubbell巴罗科罗拉多岛（BCI）森林动态项目是世界上对热带森林进行的时间最长的大规模研究，其目的是在种群和整个群落水平上测试相互竞争的理论，以维持热带潮湿森林的高树种多样性。BCI研究是自1980年以来在新旧热带地区建立的全球类似地块网络的旗舰项目和模型。目前的活动是在2000年对BCI上50公顷的地块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年前上次普查以来该地块内所有1cm dbh（240,000茎）木本植物的招募、生长和存活数据；(2)将普查范围扩大到较小的树苗类；(3)分析所有树木的命运（生长、生存）作为其当地生物邻域的函数；(4)利用邻域分析和其他信息建立BCI森林的第一代动态模型。了解这些局部邻域效应对于建立冠层树木替代的预测理论至关重要，这反过来又对理解BCI森林中树种多样性的维持至关重要。对上次普查中23万株单株13年的存活率进行了初步的邻域分析。对焦点植物的存活有显著的、通常很强的邻域效应。分析了4个邻域因子的影响：与焦点植物相同物种的邻域数、第一次至最后一次普查中不同物种间存活的邻域数、焦点植物相对于其邻域的大小以及焦点植物邻域间的物种数。如果这些结果得到下一次普查的额外数据的证实，将对理解导致热带森林群落高度树种多样性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.