Active coral restoration typically involves two interventions: crossing gametes to facilitate sexual larval propagation; and fragmenting, growing, and outplanting adult colonies to enhance asexual propagation. From an evolutionary perspective, the goal of these efforts is to establish self‐sustaining, sexually reproducing coral populations that have sufficient genetic and phenotypic variation to adapt to changing environments. Here, we provide concrete guidelines to help restoration practitioners meet this goal for most Caribbean species of interest. To enable the persistence of coral populations exposed to severe selection pressure from many stressors, a mixed provenance strategy is suggested: genetically unique colonies (genets) should be sourced both locally as well as from more distant, environmentally distinct sites. Sourcing 3‐4 genets per reef along environmental gradients should be sufficient to capture a majority of intraspecies genetic diversity. It is best for practitioners to propagate genets with one or more phenotypic traits that are predicted to be valuable in the future, such as low partial mortality, high would healing rate, high skeletal growth rate, bleaching resilience, infectious disease resilience, and high sexual reproductive output. Some effort should also be reserved for underperforming genets because colonies that grow poorly in nurseries sometimes thrive once returned to the reef and may harbor genetic variants with as yet unrecognized value. Outplants should be clustered in groups of 4‐6 genets to enable successful fertilization upon maturation. Current evidence indicates that translocating genets among distant reefs is unlikely to be problematic from a population genetic perspective but will likely provide substantial adaptive benefits. Similarly, inbreeding depression is not a concern given that current practices only raise first‐generation offspring. Thus, proceeding with the proposed management strategies even in the absence of a detailed population genetic analysis of the focal species at sites targeted for restoration is the best course of action. These basic guidelines should help maximize the adaptive potential of reef‐building corals facing a rapidly changing environment.
Despite widespread climate-driven reductions of coral cover on tropical reefs, little attention has been paid to the possibility that changes in the geographic distribution of coral recruitment could facilitate beneficial responses to the changing climate through latitudinal range shifts. To address this possibility, we compiled a global database of normalized densities of coral recruits on settlement tiles (corals m-2) deployed from 1974 to 2012, and used the data therein to test for latitudinal range shifts in the distribution of coral recruits. In total, 92 studies provided 1253 records of coral recruitment, with 77% originating from settlement tiles immersed for 3-24 mo, herein defined as long-immersion tiles (LITs); the limited temporal and geographic coverage of data from short-immersion tiles (SITs; deployed for <3 mo) made them less suitable for the present purpose. The results from LITs show declines in coral recruitment, on a global scale (i.e. 82% from 1974 to 2012) and throughout the tropics (85% reduction at <20° latitude), and increases in the sub-tropics (78% increase at >20° latitude). These trends indicate that a global decline in coral recruitment has occurred since 1974, and the persistent reduction in the densities of recruits in equatorial latitudes, coupled with increased densities in sub-tropical latitudes, suggests that coral recruitment may be shifting poleward.
It is critical to evaluate the in situ effects of multiple stressors on coastal community dynamics, especially those communities harboring high diversity such as coral reefs, in order to understand the resilience of these ecosystems, prepare coastal management for future scenarios, and aid in prioritizing restoration efforts. In this in situstudy, at 2 sites with gradients of submarine groundwater discharge (SGD), a suite of physical parameters (wave exposure index, wind exposure index, and depth) and an all-encompassing SGD chemical parameter (average nitrate + nitrite daily load) were measured along spatially cohesive and temporally relevant scales and used to model macroalgal growth, biomass, and diversity in Maunalua Bay, Hawai‘i. We showed that (1) species-specific macroalgal biomass is significantly related to SGD and one of the 2 exposure indices (i.e. wind exposure or wave exposure), (2) SGD and wave exposure play key roles in species-specific growth rates, and (3) SGD supports low diversity and increased biomass of species that can tolerate the biogeochemistry associated with SGD. Our work suggests that SGD and local hydrodynamics predict local variation in macroalgal growth, biomass, and diversity in tropical reefs.
Tourists often travel to experience the natural beauty of a destination such as the Great Barrier Reef (GBR) in Australia. This nature-based destination attracts millions of tourists every year because of its outstanding underwater aesthetics. Recently, parts of the GBR have been degraded by warming sea temperatures and other local anthropogenic influences, threatening the Reef aesthetics and tourism in the region. In order to deal with this topical issue, the current research investigates tourists’ aesthetic assessment of environmental changes in the GBR ecosystem. Research outcomes indicate that tourists’ perceived beauty of the Reef is sensitive to environmental changes. The disappearance of sea animals (colourful fish, turtle), degrading coral and decreasing water quality negatively influence their aesthetic assessment, which can reduce tourist visitation in the long-term. Hence, sustainable tourism development in the GBR regions can only be achieved when government support for environmental management is strengthened. Conservation programs of the GBR should expand beyond coral restoration for controlling water quality, reducing pollution and protecting aesthetically appealing sea animals.
Passive acoustic sensors provide a cost-effective tool for monitoring marine environments. Documenting acoustic conditions among habitats can provide insights into temporal changes in ecosystem composition and anthropogenic impacts. Agencies tasked with safeguarding marine protected areas, such as the U.S. National Park Service and U.S. National Oceanic and Atmospheric Administration’s Office of National Marine Sanctuaries, are increasingly interested in using long-term monitoring of underwater sounds as a means of tracking species diversity and ecosystem health. In this study, low-frequency passive acoustic recordings were collected fall 2014 – spring 2018, using standardized instrumentation, from four marine protected areas across geographically disparate regions of the U.S. Economic Exclusive Zone: Northwest Atlantic, Northeast Pacific, South Pacific, and Caribbean. Recordings were analyzed for differences in seasonal conditions and to identify acoustic metrics useful for resource assessment across all sites. In addition to comparing ambient sound levels, a species common to all four sites, the humpback whale (Megaptera novaeangliae), was used to compare biological sound detection. Ambient sound levels varied across the sites and were driven by differences in animal vocalization rates, anthropogenic activity, and weather. The highest sound levels [dBRMS (50 Hz–1.5 kHz)re 1 μPa] were recorded in the Northwest Atlantic in Stellwagen Bank National Marine Sanctuary (Stellwagen) during the boreal winter–spring resulting from bioacoustic activity, vessel traffic, and high wind speeds. The lowest sound levels [dBRMS (50 Hz–1.5 kHz) re 1 μPa] were recorded in the Northeast Pacific adjacent to a vessel-restricted area of Glacier Bay National Park and Preserve (Glacier Bay) during the boreal summer. Humpback whales were detected seasonally in the southern latitude sites, and throughout the deployment periods in the northern latitude sites. Temporal trends in band and spectrum sound levels in Glacier Bay and the National Park of American Samoa were primarily driven by biological sound sources, while trends in Stellwagen and the Buck Island Reef National Monument were primarily driven by anthropogenic sources. These results highlight the variability of ambient sound conditions in marine protected areas in U.S. waters, and the utility of long-term soundscape monitoring for condition assessment in support of resource management.
Species extinctions are occurring at an unprecedented rate and there is a global need to understand whether conservation effort is appropriately allocated to protect those species at risk. In this study three major measures of global conservation effort across IUCN Red List Threats and Habitats were assessed; staff time spent by the largest cluster of conservation organizations in the world—Cambridge Conservation Initiative, efforts by international NGOs through social media, and global conservation research publications since the year 2000. We find global conservation effort is generally aligned with global conservation priorities, but there are important outliers. Shrublands and rocky areas receive disproportionately little investment across all effort measures relative to the number of high extinction risk species, threats from residential and commercial development receive relatively low research and time investment despite social media attention, while marine areas and climate change receive more attention than expected. Governments and society must make critical conservation decisions in the context of rapid global change, and there is potential for key Threats or Habitats to receive less attention than required. The global conservation community would be wise to carefully consider and improve its understanding of effort-priority mismatches if the greatest number of high extinction risk species are to be protected.