Ingestion of L. ferrea and S. spectabilis Seeds from the Caatinga by Goats and Sheep Enhances Germination and Vigor

Abstract Endozoochory in dry tropical forests is a phenomenon that ensures species perpetuation, due to its positive effects on seed germination and plant establishment. However, the mechanisms behind this germinative success are poorly understood. This study aimed to analyze the ingestion of Libidibia ferrea and Senna spectabilis seeds by goats and sheep and the effect on dormancy and morphophysiological qualities. Four hundred seeds of each species were provided in the feed base of goats and sheep, followed by an evaluation of the recovery rate, germination (%), germination speed index, mean germination time, shoot and root length, and seedlings dry mass. The recovery of seeds from sheep occurred more rapidly (within 48 hours for both species) in the first hours after ingestion, while for goats, this process occurred slowly and over a more extended period, which may potentially favor the perpetuation of the species within the habitat. To elucidate the study, it was noted that vigor variables, dry mass, and germination speed index contribute most to the data explanation for L. ferrea seeds, whereas for S. spectabilis seeds, the germination showed intermediate contribution, suggesting its relevant role in this species. Dormancy of L. ferrea and S. spectabilis seeds can be broken when ingested by goats and sheep, indicating that the passage of the seeds through the digestive system enhances their physiological quality in comparison to those that were not ingested by these animals.