Moya S.

Long-term dynamics of organic matter and elements exported as coarse particulates from two Caribbean montane watersheds

Heartsill Scalley, T., Scatena, F.N., Moya S., Lugo A.E., 2012 Long-term dynamics of organic matter and elements exported as coarse particulates from two Caribbean montane watersheds. Journal of Tropical Ecology. Vol 28. pp 127-139. doi:10.1017/S0266467411000733


This paper compares aboveground forest structure and macronutrient stoichiometry over 5 15 years of hurricane induced secondary succession by species, life history groups, community 6 species composition, and geomorphic setting. Stem density continually increased after the 7 impact of the Category 4 hurricane Hugo and 15 years later, it was greater than pre-hurricane. 8 There were significant spatial and temporal differences in the number of species, the diversity 9 index per plot, forest structure, and biomass. The greatest compositional differences occurred 10 between the post-Hugo and the 15-year census. Prior to hurricane Hugo most plots had very 11 similar species composition and abundances, and thus occupied a small area in non-metric 12 multidimensional species space. Following the hurricane new species combinations occurred 13 and the location of plots was spread in multidimensional space. Diversity indices were 14 significantly different among geomorphic settings before and immediately after hurricane Hugo. 15 However, these differences were not observed again until the 15-year census where they returned 16 to pre-hurricane levels. Plant associations based on abundance, life history traits, and landscape 17 position had measurable differences in their structure, composition, aboveground nutrient 18 storage, and stoichiometry. However, these differences were reflected in a variety of ways at 19 different spatial scales. At the species level differences in macronutrient tissue concentrations 20 were apparent when comparing co-existing primary forests dominants, early successional 21 dominants, high-light and low-light species, and species whose stem densities are negatively 22 correlated. Community level differences were greater for forest structure and total nutrient 23 storage compared to the mass weighted concentrations of macronutrients. The largest differences observed were in Mg and can be attributed to the succession of pioneer species 2 following the hurricane. Over the entire 15-year period, the watershed average aboveground 3 stoichiometry was relatively consistent and this is linked to the biomass dominance of a few 4 species. The successional history recorded here also suggests that community level differences 5 in species composition, structure, and stoichiometry were well established after 10 to 15 years of 6 secondary succession.

The First five years in the reorganization of aboveground biomass and nutrient use following hurricane Hugo in the bisley Experimental Watersheds, luquillo Experimental Fortest, Puerto Rico

Scatena, F. N. ; Moya, S.; Estrada, C; Chinea, J.D. 1996. The First five years in the reorganization of aboveground biomass and nutrient use following hurricane Hugo in the bisley Experimental Watersheds, luquillo Experimental Fortest, Puerto Rico. Biotropica 28(4) : 424-440.

Five years after Hurricane Hugo reduced the aboveground biomass by 50 percent in two forested watersheds in the Luquillo Experimental Forest of Puerto Rico, regeneration and growth of survivors had increased the aboveground biomass to 86 percent of the pre-hurricane value. Over the 5 yr, the net aboveground productivity averaged 21.6 Mg·ha-1·yr-1 and was faster than most plantations and secondary forests in the area. Woodfall and associated nutrient fluxes never attained pre-storm values but by the fifth yr, mean daily total litterfall, and N, P, K, Ca, and Mg fluxes in litterfall were 83, 74, 62, 98, 75, and 81 percent of their pre-disturbance values, respectively. Aboveground nutrient pools of these nutrients ranged from 102 to 161 percent of their pre-disturbance values and were larger after 5 yr because of higher nutrient concentrations in the regeneration compared to the older wood that it replaced. The following sequence of ecosystem reorganization during this first 5 yr period is suggested. An initial period of foliage production and crown development occurred as hurricane survivors re-leafed and herbaceous vegetation and woody regeneration became established. During this period, 75 to 92 percent of the nutrient uptake was retained in the aboveground vegetation and there was a relatively low rate of aboveground carbon accumulation per mole of nutrient cycled. This initial period of canopy development was followed by a peak in aboveground productivity that occurred as early successional species entered the sapling and pole stages. This period was followed by the establishment of the litterfall nutrient cycle and an increase in the net productivity per mole of nutrient cycled. During this 5 yr period, the Bisley forest had some of the lowest withinstand nutrient-use-efficiencies and some of the highest levels of aboveground productivity ever observed in the LEF. The study demonstrates that high levels of productivity and rapid rates of aboveground reorganization can be achieved with rapid within-system cycling and inefficient within-stand nutrient use.

Changes in Structure, Composition, and Nutrients During 15 Yr of Hurricane-Induced Succession in a Subtropical Wet Forest in Puerto Rico

Heartsill Scalley, Tamara; Scatena, Frederick N.; Lugo, Ariel E.; Moya, Samuel; Estrada Ruiz, Carlos R. 2010. Changes in structure, composition, and nutrients during 15 years of hurricane-induced succession in a subtropical wet forest in Puerto Rico. Biotropica. 42(4): 455-463.

The trajectory of hurricane-induced succession was evaluated in a network of forest plots measured immediately before and 3 mo, 5, 10, and 15 yr after the direct impact of a Category 4 hurricane. Comparisons of forest structure, composition, and aboveground nutrients pools were made through time, and between species, lifehistory groups and geomorphic settings. The hurricane reduced aboveground biomass by 50 percent, causing an immediate decrease in stem density and diversity indices among all geomorphic settings. After 15 yr, basal area and aboveground biomass returned to pre-hurricane levels, while species richness, diversity indices, and stem densities exceeded pre-hurricane levels. Differences in species composition among geomorphic settings had not returned after 15 yr but differences in stem densities and structure were beginning to emerge. Significant differences were observed in the nutrient concentration of the three species that comprised the most aboveground biomass, and between species categorized as secondary high-light species and primary, low-light species. Species whose abundance was negatively correlated with the mature forest dominant also had distinct nutrient concentrations. When total aboveground nutrient pools were compared over time, differences in leaf nutrients among species were hidden by similarities in wood nutrient concentrations and the biomass dominance of a few species. The observed successional trajectory indicates that changes in species composition contributed to fast recovery of aboveground biomass and nutrient pools, while the influence of geomorphic setting on species composition occurs at time scales 415 yr of succession.
Syndicate content