Seasonal Reproduction in Neotropical Rainforest Mammals

摘要

Seasonal changes in tropical forestshave been documented in dry and semi-deciduous forests, but not in evergreen ones. Owingto its high level of annual rainfall, French Guiana is considered to be a rainy region,despite a pronounced dry season. French Guiana is therefore appropriate for studying theimpact of the dry season on the phenology of rainforest animals. For this purpose, thereproductive characteristics of six terrestrial mammals of the French Guiana rainforestwere studied during the four main seasons of the year. Reproduction was more or lesscontinuous in both sexes of all species. Seasonality was not very pronounced and thespecies were not synchronised, except in terms of births. In all species, the minimumnumber of litters occurred between August and October. Furthermore, the seasonal birthpercentages appeared to be linked to environmental factors such as rainfall and fruitingtrees, and to diet as well: the more the diet of one species was composed of fruits, themore seasonal its litters were. Thus, like in many other regions worldwide, most birthsoccur during the most favourable seasons for raising young in this rainforest. This signies that even in this seemingly aseasonal region, the reproduction of mammals is mainlyregulated by environmental factors at the time of birth.