De baixo para cima: minhocas como carreadoras de propágulos de briófitas

Abstract

Bryophytes also benefit from zoocoria for their dispersal, as do tracheophytes. One can cite, for example, flies, slugs, ants, and vertebrates such as birds and mammals. The field of animal-bryophyte interactions is mostly composed of field studies, with a few experimental researches. Therefore, it has great potential for testing hypotheses involving these organisms. Bryophytes perform important ecological services such as soil stabilization, rehabilitation of eroded soil, and facilitating the establishment of vascular plants. By performing so many roles in the ecosystem, it is necessary to know the various ways in which bryophytes reproduce and disperse. Given their important role, this study evaluated the dispersal ability of bryophytes by earthworms through a controlled experiment. Three species of bryophytes were used, Chryso- hypnum diminutivum (Hampe) W.R. Buck, Hyophila involuta (Hook) A. Jaeger, Fossombronia porphyrorhiza (Nees) Prosk., to be ingested by red worms, Eisenia andrei Bouché. There were two treatments: "bryophyte dust", which consisted of plant fragments obtained by grinding against a sieve, and "bryophyte square", a 16cm² plot of the collected colony. The annelids came in contact with the plants for a period of seven days and were removed for fasting. After 2 days in isolation, the feces were collected and placed to germinate in airtight containers with vermiculite. Each treatment with 6 repetitions, including the control groups. Bryophyte growth was observed in 47.22% of the sample units with inoculation of plants by annelid feces, corroborating the initial hypothesis. The species that did best was H. involuta, followed by F. porphyrorhiza and then C. diminutivum. It is assumed that the species H. involuta obtained greater dispersal of units due to the production of gemmae, which were ingested and dispersed in large numbers. While F. porphyrorhiza was able to disperse, probably, by the production of large spores, characteristic of the genus. The bryophyte dust treatment showed more plant emergings inoculated with feces than the bryophyte square. The efficiency of the bryophyte dust can be explained by the fragments being easier for the animals to ingest. This is the first controlled experiment that supports the hypothesis that earthworms can disperse bryophytes. This study also opens up a range of possibilities for thinking about how earthworms interact with and impact terrestrial bryophyte colonies. For example, building robust metapopulation structures or how the digestive tract of earthworms can influence the breakdown of gemmae and spore dormancy.