Gilbert G S, Foster R B, Hubbell S P
Smithsonian Tropical Research Institute, Box 2072, Balboa, Panama.
Department of Botany, Field Museum, 60607, Chicago, IL, USA.
Oecologia. 1994 Jun;98(1):100-108. doi: 10.1007/BF00326095.
We compared the spatial distribution of stem cankers on the canopy tree Ocotea whitei (Lauraceae) in a 20-ha plot on Barro Colorado Island, Panama, with spatial and temporal patterns of mortality in this host over the previous decade. The cankers occur both on adult and juvenile individuals, aothough juveniles are much more likely the adults to show symptoms. Disease incidence is host-density dependent, and both the presence of the disease and host mortality are more likely close to than far from a conspecific adult, which resulted in a net spatial shift of the juvenile population away from conspecific adults through time. Disease incidence is lower than expected among juveniles of O. whitei growing near to adults of the non-susceptible canopy tree Beilschmiedia pendula. The coincidence of spatial patterns of canker incidence and host mortality suggest a role for the disease in regulating host spatial distribution, in agreement with predictions of the Janzen-Connell hypothesis.
我们比较了巴拿马巴罗科罗拉多岛一片20公顷土地上，树冠层树木白樟（樟科）树干溃疡病的空间分布，以及过去十年该寄主死亡情况的时空模式。溃疡病在成年和幼年个体上均有发生，不过相较于成年个体，幼年个体出现症状的可能性要大得多。疾病发病率取决于寄主密度，并且疾病的存在和寄主死亡情况在靠近同种成年个体处比远离处更为常见，这导致幼年种群随着时间推移在空间上逐渐远离同种成年个体。在不易感的树冠层树木垂枝琼楠成年个体附近生长的白樟幼树中，疾病发病率低于预期。溃疡病发病率和寄主死亡情况的空间模式相吻合，这表明该疾病在调节寄主空间分布方面发挥了作用，这与简森 - 康奈尔假说的预测相符。
