[Effects of disturbances on animal-mediated seed dispersal effectiveness of forest plants: A review]

Abstract

Disturbances commonly exist in forest ecosystems and play a critical role in the forest regeneration and succession. Animal-mediated seed dispersal is an essential stage of seed regeneration for most plants. To some extent, the responses of animal-mediated seed dispersal to forest disturbances can predict the changes in community composition and structure, and consequently, the succession direction of forests. In the present study, we systematically discussed the ecological significance of the effects of disturbances on animal-mediated seed dispersal effectiveness (i.e., quantity and quality of seed dispersal) of forest plants. We also revealed the research progresses on the effects of natural disturbances (e.g., fire and forest gaps) and human disturbances (e.g., habitat fragmentation, hunting and logging) on the seed dispersal quantity, distance and seedling rege-neration after seed dispersal. The responses of seed dispersal quantity to disturbances were embodied in the dynamic changes of animal population. In addition, there was a slightly negative correlation between seed dispersal distance and interference. However, it was much more complicated for the influences of disturbance on seedling regeneration due to the various types of disturbances, and the environmental factors in disturbed areas also affected seed germination and seedling regeneration after seed dispersal. There were some problems of the study on the effects of disturbances on animal-mediated seed dispersal effectiveness of forest plants. Little was known about the effects of recovery processes of fire disturbance region and positive disturbances (e.g., tending, thinning and forest gaps) on the seed dispersal effectiveness, especially in the temperate forest ecosystems. In the future, long-term research on seed dispersal effectiveness of forest plants by animals after disturbances should be carried out, and the effects of positive disturbances on animal-mediated seed dispersal should be emphasized for the forest regions prone to disturbance.

Keywords: human disturbance; natural disturbance; seed dispersal distance; seed dispersal quantity; seedling regeneration.