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Strategies for integrating sexually propagated corals into Caribbean reef restoration: experimental results and considerations

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Abstract and Figures

Caribbean hard coral cover has decreased by more than 80% in the last 40 years. In response, active coral restoration has grown in popularity as a management tool to sustain degraded reefs. To date, the majority of coral outplanting has employed asexually propagated ramets derived from wild donor colonies. Unfortunately, this strategy is incapable of increasing genetic diversity and limits the adaptive potential of restored coral populations. Methods for sexual propagation in land-based systems offer increasing potential to enhance genetic diversity of target species. However, questions regarding coral performance once placed back into the dynamic marine environment must be considered. Thus, focused experiments to optimize the integration of land reared corals and novel genetic diversity are of immense value. For this reason, we designed a study using two Acropora cervicornis year classes produced in a land-based system and concurrently relocated to an inshore patch reef, a back reef, and placed in an ocean-based nursery (n = 80 sexually propagated colonies per location). A deliberate monitoring strategy measured growth and survival five times over a 480-day period. Major findings were 1) high survival rates (~ 73%) across all 160 outplanted colonies 2) significant differences in survival between outplanting locations and coral recruit year class, and 3) very high survival of sexually propagated corals relocated to the ocean-based nursery (~ 93% overall), with 40-fold greater growth than direct-outplanted colonies. Our study suggests that ex situ sexual coral propagation offers a tractable tool to meet the need for increased A. cervicornis genetic diversity. Lastly, we offer insight and considerations for managing the high input of novel genotypes into restoration systems and suggest further research to maximize the adaptive potential of coral populations.
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REPORT
Strategies for integrating sexually propagated corals
into Caribbean reef restoration: experimental results
and considerations
Joseph A. Henry
1
Keri L. O’Neil
2
Aaron R. Pilnick
3
Joshua T. Patterson
1,2
Received: 3 March 2021 / Accepted: 30 June 2021 / Published online: 14 July 2021
ÓThe Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021
Abstract Caribbean hard coral cover has decreased by
more than 80% in the last 40 years. In response, active
coral restoration has grown in popularity as a management
tool to sustain degraded reefs. To date, the majority of coral
outplanting has employed asexually propagated ramets
derived from wild donor colonies. Unfortunately, this
strategy is incapable of increasing genetic diversity and
limits the adaptive potential of restored coral populations.
Methods for sexual propagation in land-based systems
offer increasing potential to enhance genetic diversity of
target species. However, questions regarding coral perfor-
mance once placed back into the dynamic marine envi-
ronment must be considered. Thus, focused experiments to
optimize the integration of land reared corals and novel
genetic diversity are of immense value. For this reason, we
designed a study using two Acropora cervicornis year
classes produced in a land-based system and concurrently
relocated to an inshore patch reef, a back reef, and placed
in an ocean-based nursery (n= 80 sexually propagated
colonies per location). A deliberate monitoring strategy
measured growth and survival five times over a 480-day
period. Major findings were 1) high survival rates
(*73%) across all 160 outplanted colonies 2) significant
differences in survival between outplanting locations and
coral recruit year class, and 3) very high survival of sex-
ually propagated corals relocated to the ocean-based
nursery (*93% overall), with 40-fold greater growth than
direct-outplanted colonies. Our study suggests that ex situ
sexual coral propagation offers a tractable tool to meet the
need for increased A. cervicornis genetic diversity. Lastly,
we offer insight and considerations for managing the high
input of novel genotypes into restoration systems and
suggest further research to maximize the adaptive potential
of coral populations.
Keywords Coral outplanting Acropora Genetic
diversity Adaptive management Threatened species
Introduction
Coral reefs are disappearing globally at an alarming rate
(Burke et al. 2013; Pratchett et al. 2014). Disease (Walton
et al. 2018; Muller et al. 2020), elevated ocean tempera-
tures (De’ath et al. 2012), extreme weather events
(Woodley et al. 1981; Dahlgren and Sherman 2020), and
pollution (Bak 1987; Edinger et al. 1998) have led to a
precarious and uncertain future for coral reefs. Continued
degradation of these ecosystems could have extensive
consequences as they provide a multitude of environmental
and economic benefits including coastal protection, tour-
ism, and a source of food (Burke et al. 2013; Massel and
Gourlay 2000; Cinner 2014). In the Caribbean, hard coral
cover has decreased by more than 80% in the last 40 years
(Gardner et al. 2003; Maynard et al. 2017, NOAA 2018).
Staghorn coral Acropora cervicornis was historically a
dominant reef building species throughput this region
Topic Editor Anastazia Teresa Banaszak
&Joseph A. Henry
henry8404@ufl.edu
1
Program in Fisheries and Aquatic Sciences, School of Forest,
Fisheries, and Geomatics Sciences, University of Florida/
IFAS, 7922 NW 71st Street, Gainesville, FL 32653, USA
2
Center for Conservation, The Florida Aquarium, 529 Estuary
Shore Lane, Apollo Beach, FL 33572-2205, USA
3
Interdisciplinary Ecology, School of Natural Resources and
Environment, University of Florida/IFAS, 103 Black Hall,
Gainesville, FL 32611, USA
123
Coral Reefs (2021) 40:1667–1677
https://doi.org/10.1007/s00338-021-02154-2
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
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