Dieta e potencial de dispersão de sementes por canídeos no Cerrado

Abstract

The order of carnivores has several representatives that consume fruit and could potentially act in seed dispersal. Despite this, few Neotropical carnivore species have their diet studied in detail, including identification of plant material, and their potential as seed dispersers, especially in relation to qualitative and quantitative aspects. In this study, we highlight two species of canids (Canidae, Carnivora), the Maned wolf (Chrysocyon brachyurus) and the Crab-eating fox (Cerdocyon thous), which simultaneously have a diet based largely on frugivory and great potential as seed dispersers. We quantified the diet of both canids based on fecal samples obtained in the field in southeastern Brazil for 15 months. The Maned wolf showed an omnivorous, generalista diet, based mainly on rodents, birds, various fruits and the fruit of the wolf tree (Solanum lycocarpum). The diet varied seasonally: The Maned wolf consumed more rodents and S. lycocarpum during the dry season, while the other fruits were consumed more during the rainy season. In addition, the Maned wolf positively selected some prey such as the rodent genera Necromys and Clyomys, and some fruits (such as Psidium grandifolium and S. lycocarpum). Regarding the role of these canids in seed dispersal, we compared the germination percentage and time of seeds that had passed through their digestive tract with seeds planted with fruit pulp and seeds cleaned by hand. For the Maned wolf, we identified that 18 species, out of the 23 present in its diet, to have viable seeds after ingestion. For the Crab-eating fox, from 12 species present in its diet, eight has seeds viable after being eaten. Both canids proved to be legitimate dispersers of Cerrado species, mainly of plants with medium and large fruits (>1cm), but also of species with smaller fruits (Miconia sp.). From the 14 plant species tested, five germinated more after passing through the digestive tract of canids compared to the controls, while two germinated less. For the other species there was no difference in the germination percentage between the seeds defecated and those in whole fruits. Finally, by calculating the gut passage time of the Crab-eating fox (17.8 ± 5 hs), it is possible to infer they can deposit seeds at long distances from the mother plant. The study made it possible to deepen our knowledge about the diet of the Maned wolf, highlighting which resources are essential for their occurrence in natural areas, providing us with information on food selectivity and how seasonality influences its diet. Finally, it allowed us to affirm their legitimacy as seed dispersers for many species and to understand their importance for the dynamics and maintenance of this process in the Cerrado.