Spatial and Temporal Changes in the Demography of Caulerpa paspaloides along a Distance Gradient

Fuentes-Agueda, S.A.; Gallegos, M.E., and Mandujano, M.C., 2024. Spatial and temporal changes in the demography of Caulerpa paspaloides along a distance gradient. Journal of Coastal Research, 40(5), 952–961. Charlotte (North Carolina), ISSN 0749-0208. It has been proposed that Caulerpa species have greater abundances and growth rates near mangroves than offshore. The main purpose of this study was to observe the demographic differences in Caulerpa paspaloides in three different sites of Los Petenes, Campeche, Mexico (adjacent to the mangroves, at an intermediate distance to the mangroves and offshore). For the demographical census, the number of complete and incomplete fronds, stolons, their diameter, and dry biomass was registered in May, August, and December 2013 and February 2014 for each site. Also, 100 complete fronds in May and December were marked; they were collected in June and February based on growth data obtained through the marked fronds and calculable dry biomass population growth rate (k). Significant differences were found between the abundance of structures between sites and months. The offshore population had the biggest biomass and highest average stolon diameter, whereas the intermediate site has the highest number of complete and incomplete fronds. However, no significant differences in the number of stolons were found. The values of fitness (k) obtained from the analysis of the biomass were 2.06 in summer and 0.68 in winter adjacent to the mangroves, intermediate distance was 1.57 and 1.26, and distance to offshore was 1.56 and 0, respectively. For marked fronds, the fitness (k) was 1.78 for the first site, 1.89 at the intermediate site, and 1.67 offshore. Reduction in C. paspaloides fitness suggests that the species has seasonal growth and reproduction. Also, the most important parameters related to C. paspaloides biomass were salinity and nutrients (total phosphorus and dissolved inorganic nitrogen in column water). The greatest growth rates in biomass were observed close to the mangroves, suggesting that living close to the mangrove has positive effects on the growth of C. paspaloides.