Can small hornbills act as substitute seed dispersers for large hornbills?

我研究了泰国热带森林中的犀鸟，以了解它们的运动模式，并评估它们作为种子传播者的有效性。为了估计犀鸟对特定树种种子阴影的贡献，我结合了无线电跟踪确定的移动数据和种子通道试验的数据。结合这些数据，我估计小型犀鸟的种子传播距离的中位数和最大距离比大型物种的要短。小型犀鸟不能与大型犀鸟交替发挥生态作用，因此大型犀鸟的丧失可能会导致热带森林中许多犀鸟散布植物的种子传播距离缩短。

I studied hornbills in the tropical forests of Thailand, to understand their movement patterns and evaluate their effectiveness as seed dispersers. To estimate hornbill contribution to a particular tree species’ seed shadow I combined data from movements, determined by radio-tracking, with data from seed passage trials. Combining these data, I estimated that the median and maximum seed dispersal distances of small hornbills were shorter than those of larger species. Small hornbills are not able to alternate ecological roles with large hornbills, and thus loss of large hornbills may lead to reduce seed dispersal distances for many hornbill-dispersed plants in tropical forests.