Sunday, February 19, 2017
Exhibit Hall (Hynes Convention Center)
Johnathan Velazquez, Universidad del Turabo, Gurabo, PR
Background: Hurricanes generate disturbances in forests such as canopy opening, fallen trees and leaves which in turn alter physicochemical characteristics of the habitat, as well as, decomposer activity. Litter decomposition depends primarily on the interaction among climate, litter quality and biota; as a consequence any change in habitats will result in changes in these factors. Identifying the changes in the fungal community structure in soil and forest floor litter can help understand the factors that influence ecosystem recovery. Methods: This study is part of the Canopy Trimming Experiment 2 performed by the Luquillo LTER at El Verde Field Station. For this, three blocks (A, B and C) were selected, each with two plots of 20m x 20m, one plot was used for control and the other was subject to canopy opening and debris addition (Trim plus debris). In each subplot, litterbags with different mesh sizes (small, medium and large) were placed. This experimental design represents 3 blocks x 2 plots/block (1 trim+debris/ 1 control) x 3 subplots x 3 litterbag mesh sizes x 4 collecting times (3, 5, 12 and 24 weeks), for a total of 216 litterbags. A pool sample for each mesh size from the 3 subplots/per plot/time was obtained for DNA extraction. DNA was extracted using Power Soil DNA Isolation kit from MoBio. The TRFLP technique was used to obtain the profiles of the fungal communities of each sample using the fungal ITS region. The diversity between samples was analyzed using NMDS and UPGMA Cluster analysis using the Bray-Curtis similarity index. Results:Two way Permanova shows significant differences in fungal communities between blocks, control and trim plus debris, and mesh size. No significant differences were observed through time. In general the diversity of fungal communities increase in the trim plus debris treatment. This increase is mainly due to the addition of detritus which increases soil moistures. Conclusion: Fungi are the main decomposers of detritus in the forest floor and the effect of natural disturbances such as a hurricane on leaf litter microbial communities will help us understand how litter decomposition might be affected. This one component of a larger study that is analyzing the interaction between arthropods, microorganisms, nutrient mineralization and disturbances.