Microclimate and seed bank under Pithecellobium keyense (Fabaceae) in a coastal scrubland

Abstract

Microclimatic conditions affect seeds' survival, dormancy, and germination, which are determinants in vegetation succession and recovery. The semiarid coastal scrublands of Yucatan, Mexico are very important because of the environmental services they provide thus, studies are needed in disturbed sites in relation to seed viability and microclimate. In this study, we characterized the microclimate and seed bank under Pithecellobium keyense shrubs, during the rainy and dry seasons. We collected soil samples and measured microenvironmental variables under adult P. keyense at three different positions under the canopy of every studied individual (“open” or completely sunny, “half-shaded,” placed at the border of the canopy, and “fully shaded” placed under the canopy, next to the stem of the shrub). Photosynthetic photon flux density (PPFD), minimum night-time temperature, and maximum daytime temperature behaved differently among positions under the canopy both in rainy and dry seasons. During the rainy season, seed viability was no different among microenvironments, while in the dry, the highest was found in the fully shaded and the lowest in the open position. Microclimatic variables under the canopy of P. keyense had an effect on the probability of seed viability in Chuburná; and this effect was stronger in the dry season. Abstract in Spanish is available with online material.