Mercado-Molina, A. E., Ruiz-Diaz, C. P., Perez, M. E., Rodrguez-Barreras, R., Sabat, A. M.

Demography of the threatened coral Acropora cervicornis: Implications for its management and conservation

2015

Coral Reefs

34

1-12

"Populations of Acropora cervicornis have collapsed throughout the Caribbean. This situation has prompted the initiation of many restoration efforts; yet, there are insufficient demographic data and analyses to effectively guide these initiatives. In this study we assessed the spatiotemporal variability of A. cervicornisvital rates. We also developed a population matrix model to (1) evaluate the risk of population extinction, (2) estimate population growth rates (lamda) considering different rates of colony fragmentation and fragment survival, (3) determine the demographic transition(s) that contribute the most to spatiotemporal differences in (lamda)s, and (4) analyze the effectiveness of outplanting coral fragments of different sizes. The model was parameterized by following the fate of 300 colonies from 2011 to 2013 at two localities in Puerto Rico. Demographic transitions varied spatiotemporally, with a significant interaction between location and time period on colony fate. Spatiotemporal variations in lamda were also observed. During the first year, populations exhibited (lamda)s below equilibrium (0.918 and 0.948), followed by a dramatic decline at both sites (0.535 and 0.709) during the second year. The lower (lamda)s were caused by a decrease in the probability of stasis of large-sized colonies coupled with lack of sexual recruits and a meager contribution of asexual recruitment. Spatial variations in (lamda)s were largely due to differences in the probability of medium-sized colonies advancing to the largest size class. The viability analysis forecasts that the populations will reach quasi-extinction levels of 25 % of the initial population size in less than or equal to 16 years. Numerical simulations indicate that outplanting fragments greater than or equal to 250 cm in total linear length (TLL) would result in a higher asymptotic population size than outplanting smaller fragments. We argue, however, that transplanting colonies less than or equal to 100 cm TLL will be a better management strategy because they can be produced faster and in higher numbers at coral nurseries."

Acropora cervicornis; coral demography; population viability analysis; reef restoration

10.1007/s00338-015-1341-8

Funded by UPR, NOAA grant NA10OAR41700062, NSF, and the Idea Wild Foundation

NA10OAR41700062