Rainfall and gemmiferous shoots influence asexual reproduction in two tropical mosses

Abstract

Background: For some bryophytes, asexual reproduction may be the primary means of population survival, which can be affected by rainfall and moss colony features.
 Questions and / or Hypotheses: We investigated i) how gemma output differed in two tropical epiphytic mosses with mainly asexual and sexual-asexual reproduction; ii) how is the pattern of gemmae production through an annual interval; and iii) whether gemma production in both species is correlated with rainfall and colony features (shoot density, number of gemmiferous shoots, and sexual structures) per shoot and area (cm2).
 Studied species / data description /Mathematical model: Calymperes afzelii Sw. and Syrrhopodon incompletus Schwägr.
 Study site and dates: The sampling was conducted every two months for a year at Agua Blanca State Park in Tabasco, Mexico.
 Methods: Squares were used to record the gemma production per shoot and cm2, the number of gemmiferous shoots, and shoots with sexual structures. Daily mean precipitation was obtained from a meteorological station. We analysed the effect of rainfall and colony features on gemmae production at the shoot and cm2 levels using generalized linear models.
 Results: C. afzelii produced gemmae more constantly than S. incompletus. Gemma production is higher during months of high rainfall. The rainfall and number of gemmiferous shoots are suitable predictors of gemma production.
 Conclusions: Our results exemplify how rainfall and gemmiferous shoots influence the production of asexual propagules in two mosses with different reproductive strategies in the same tropical environment. This information is essential to understand the population dynamics of tropical mosses.