Outplanted Acropora cervicornis colonies propagate across sites through fragmentation: An alternative method for defining out plant success.
Elizabeth A. Goergen & David S. Gilliam
Following the Acropora cervicornis population crash of the 1970’s and 1980’s there has been little to no natural recovery, leading to its listing as threatened under the US Endangered Species Act in 2006. To address the loss of the complex structures A. cervicornis create on reefs, an extreme intervention is necessary. Since 2001, over 60 programs throughout this species range have enhanced hundreds of acres of reefs through restoration efforts. Unfortunately, the long-term success of these programs is ill-defined because it currently depends on fate tracking of individual outplants. However, A. cervicornis is a highly ephemeral species that commonly propagates through colony dislodgement/fragmentation making it nearly impossible to fate track. This unique life history characteristic is not exclusive to wild populations, but is also evident in outplanted populations. Therefore, we evaluated an alternative method for tracking the propagation of outplants to better define success. Acropora cervicornis abundance was surveyed over a prior to, then annually following outplanting at 10 sites for 2-8 years. Results suggest that outplanted colonies are propagating across sites through fragmentation. In an extreme case, colony abundance increased by nearly 500 colonies in 5 years. However, if fate tracking was used exclusively, survival was just 30% of the 150 colonies outplanted. This suggests that the success of an outplanting program should not be defined exclusively by fate tracking of individual outplanted colonies, and this broader method for quantifying colony propagation may be suitable to determine success of outplanting at a site level rather than by individual colonies.
Nova Southeastern University Halmos College of Natural Sciences and Oceanography
Elizabeth A. Goergen & David S. Gilliam
Following the Acropora cervicornis population crash of the 1970’s and 1980’s there has been little to no natural recovery, leading to its listing as threatened under the US Endangered Species Act in 2006. To address the loss of the complex structures A. cervicornis create on reefs, an extreme intervention is necessary. Since 2001, over 60 programs throughout this species range have enhanced hundreds of acres of reefs through restoration efforts. Unfortunately, the long-term success of these programs is ill-defined because it currently depends on fate tracking of individual outplants. However, A. cervicornis is a highly ephemeral species that commonly propagates through colony dislodgement/fragmentation making it nearly impossible to fate track. This unique life history characteristic is not exclusive to wild populations, but is also evident in outplanted populations. Therefore, we evaluated an alternative method for tracking the propagation of outplants to better define success. Acropora cervicornis abundance was surveyed over a prior to, then annually following outplanting at 10 sites for 2-8 years. Results suggest that outplanted colonies are propagating across sites through fragmentation. In an extreme case, colony abundance increased by nearly 500 colonies in 5 years. However, if fate tracking was used exclusively, survival was just 30% of the 150 colonies outplanted. This suggests that the success of an outplanting program should not be defined exclusively by fate tracking of individual outplanted colonies, and this broader method for quantifying colony propagation may be suitable to determine success of outplanting at a site level rather than by individual colonies.
Nova Southeastern University Halmos College of Natural Sciences and Oceanography