Reproductive phenology of Sambucus nigra subsp. canadensis in the Abies religiosa temperate forest of the Magdalena river basin, Mexico City

Abstract

Background . Reproductive phenology studies in temperate forests of Mexico are scarce and none of them takes into account micro-environmental factors. As an example, there are no studies of the reproductive dynamics of Sambucus nigra subsp. canadensis , the elderberry. 
 Questions . How do environmental factors, at general and micro-scales are related to the production of flowers and fruits of Sambucus nigra subsp. canadensis ?
 Study species . Sambucus nigra subsp. canadensis is distributed in Abies religiosa (fir) forests of Mexico and it is associated to areas of anthropogenic disturbance.
 Study site and dates . Temperate forest in the Magdalena river basin, April 2012 to May 2013.
 Methods . The percentages of flowers and fruits of 103 individuals were registered and precipitation, temperature, light and soil chemical properties were characterized as well. To find out the relation between reproductive phenology and the environmental factors we carried out Spearman´s correlations as well as a Canonical Correspondence Analysis for the micro- environmental factors.
 Results . Percentages of flowers and fruits showed a relation with the general factors of precipitation, temperature and light. In the micro-environments with the highest light amounts the percentages of fruits were the highest, while the microenvironments with the highest nitrogen, organic matter concentrations and soil moisture, showed the highest flower percentages.
 Conclusions . We showed that general factors as well as micro-environmental ones have an influence on the proportions of flowers and fruits of the study species in different ways, these knowledges show the reproductive dynamics of this species.