Seed predation and potential seed dispersers of the narrow endemic Ceratozamia norstogii (Zamiaceae)

Abstract

In this study, we report the observation of potential seed dispersers of the endemic to Mexico and narrowly distributed Ceratozamia norstogii (Zamiaceae). Camera traps were installed in front of two plants of Ceratozamia norstogii and cone phenology until their maturity and disintegration was determined. The female cone of Ceratozamia norstogii has a development of ten months, from the time it emerges until it disintegrates. We were able to identify three stages of cone development: 1) Pre-pollination phase, 2) Pollination phase and 3) Seed maturation phase. Our results support an animal-dispersal hypothesis in Ceratozamia. Three mammals [a mouse (Pteromiscus sp.), a southern spotted skunk (Spilogale angustifrons) and a kinkajou (Potus flavus)] were recorded biting, carrying or removing seeds of Ceratozamia norstogii. The camera traps recorded no evidence of birds or other mammals coming to the cones to feed. Thus, interaction of frugivores with seeds occurs at night. The most frequent visitor was the mouse, followed by the southern spotted skunk and the kinkajou. Significant differences (GLM, p< 0.05) in visitor frequency and time for interaction were found between species. We believe that the mouse is probably the most effective seed disperser for Ceratozamia norstogii. The results presented here have evolutionary implications that can be scaled to the entire genus Ceratozamia. Specifically, short-distance dispersal promotes allopatric speciation in this group of plants.