Temporal variation and environmental relationships of an estuarine meadow of Halodule emarginata from the semiarid coast of Brazil

Abstract

This study aimed to observe temporal variations of density, biometrics and biomass of Halodule emarginata, and relationships of these characters with meteorological, physicochemical, and geomorphological variables. The survey was executed in an estuarine meadow located within the Brazilian semiarid coast by performing eight monthly samplings, four in each regional climatic season (i.e. rainy and dry). Ten samples were monthly taken with a PVC core (0.0078 m2 ), using an experimental design suitable for patched meadows. Plant changes along the months were summarized in two principal components of a Principal Component Analysis, which explained 78.3% of the observed variation. The first principal component represented the overall meadow development, and the second component a contrasting aspect between above and below ground development. In general, the population appeared more developed in the rainy season, when the meadow was densest, and the plants presented longer leaves and roots. These changes were linked to climatic variations, particularly to the number of rainy days per month. Considering that seasonal changes in H. emarginata were related to local features, additional studies on meadows growing under different environmental conditions are needed to assess its conservation status.