Using Janzen–Connell to predict the consequences of defaunation and other disturbances of tropical forests
Using Janzen–Connell to predict the consequences of defaunation and other disturbances of tropical forests
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使用 Janzen-Connell 预测热带森林动物区系丧失和其他干扰的后果
DOI：
10.1016/j.biocon.2013.01.015
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发表时间：
2013
影响因子：
5.9
通讯作者：
J. Terborgh
中科院分区：
文献类型：
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作者：
J. Terborgh
热带树木补充和多样性的Janzen-Connell（J-C）模型已经成熟，现在可以用来预测动物群落消失和其他干扰的后果。J-C描述了一个远距离的补充过程，这是由于空间上不同的种子传播率和随后的存活率。种子的人均成功率是低的生殖同种下，繁殖体被杀死的主机限制的敌人（种子捕食者，草食动物和病原体）。未分散的种子因此经历微不足道的成功，而分散的种子则受益于逃避敌人。在我们位于亚马逊秘鲁的研究点，分散的种子很少（常见物种<1/m2-yr），导致幼苗密度较低（约10000）。5 m2），这表明内部相互作用（密度依赖性，竞争）是弱的。动物区系破坏和其他干扰扭曲或缩短了传播和繁殖体生存的重要过程。种子传播最容易受到狩猎和其他干扰的影响，因为它是由大型鸟类和哺乳动物进行的，这些鸟类和哺乳动物被猎人有选择地捕获或从碎片中消失。减少分散或多或少直接导致减少招募。相比之下，补偿性调整失踪的种子捕食者似乎是常见的。因此，J-C的逃逸过程比种子传播更能适应大型脊椎动物群落的扭曲。这些原则似乎是强大的，可以用来预测的后果，动物群和其他类型的干扰热带森林。
The Janzen–Connell (J–C) model of tropical tree recruitment and diversity has come of age and can now be applied to predict the consequences of defaunation and other disturbances. J–C describes a process of recruitment at a distance that results from spatially varying rates of seed dispersal and subsequent survival. The per-capita success of seeds is low under reproductive conspecifics where propagules are killed by host restricted enemies (seed predators, herbivores and pathogens). Undispersed seeds consequently experience negligible success, whereas dispersed seeds benefit from escape from enemies. At our site in Amazonian Perú, a scant rain of dispersed seeds (<1/m2-yr for common species) gives rise to a low density of seedlings (ca. 5m2), suggesting that intracohort interactions (density dependence, competition) are weak. Defaunation and other disturbances distort or curtail the vital processes of dispersal and propagule survival. Seed dispersal is most vulnerable to hunting and other disturbances because it is disproportionately carried out by large-bodied birds and mammals that are selectively harvested by hunters or that disappear from fragments. Reduced dispersal leads more or less directly to reduced recruitment. In contrast, compensatory adjustments to missing seed predators appear to be common. Thus the escape process of J–C is more resilient to distortions in the large vertebrate community than is seed dispersal. These principles appear to be robust and can be employed to predict the consequences of defaunation and other kinds of disturbances to tropical forests.