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The realized niche of many sessile intertidal organisms is constrained by different stressors that set boundaries for their distribution based on tidal elevation. Higher tidal elevation increases desiccation risk but can provide a refuge from predation. Conversely, deeper water increases feeding time and growth but also increases vulnerability to benthic predators. Eastern oystersCrassostrea virginicaharden their shells in response to predator cues, which reduces their mortality from predation. We performed a field study to investigate if this defense mechanism could be manipulated to expand their realized niche and increase space for oyster survival and growth. We raised oysters in the presence of predators (blue crabsCallinectes sapidus) or in no-predator controls, measured changes in shell morphology, and then monitored oyster survival at different tidal elevations across 7 locations with different predator and salinity regimes. Oyster survival was significantly higher at the highest tidal elevations tested. Exposure to predators before deployment also significantly increased shell hardness and survival, with intertidal oysters experiencing greater improvement in survival from cue exposure than subtidal oysters. Intertidal placement (>15% exposure time) had larger effects on survival than predator exposure, but predator exposure increased oyster survival at all tidal elevations, suggesting that predator induction could help oysters both deter predators and resist abiotic stressors like desiccation, and perhaps increase the spatial areas where oysters can be restored.
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Exploring high intertidal refugia as an approach for the restoration of an intertidal oyster
Marine organisms frequently inhabit intertidal zones that serve as refuges from predation and competition but are not optimal physiologically. Restoration practitioners working with intertidal species may similarly have to consider whether restoration success will be greater where conditions are more benign (usually lower in the intertidal) or where negative biotic interactions are reduced (usually higher in the intertidal). In cases where a target species has greater desiccation tolerance than its enemies, restoration may be more successful higher in the intertidal zone, despite potential performance trade-offs. In many US West Coast estuaries, non-native drill species can decimate native oyster populations, posing a challenge to restoration. Given that native Olympia oystersOstrea luridashould be better able to withstand tidal emersion than the non-native Atlantic oyster drillUrosalpinx cinerea, we explored using the high intertidal as a refuge from predation as a potential restoration technique. Using surveys and a field experiment, we investigated the recruitment, growth, and survival of oysters as well as drill abundance and predation over 3 tidal elevations. Oysters recruited and survived equally well at +0.1, +0.5, and +0.8 m mean lower low water, but juvenile oyster growth decreased with increasing elevation. In our experiment, predation on oysters was lower at the highest elevation than at low and mid elevations, but in natural populations there was a near complete absence ofO. luridaat any elevation whereU. cinereawas present. This suggests that a higher tidal elevation refuge is not a viable approach for oyster restoration in our study area.
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- Award ID(s):
- 2023571
- PAR ID:
- 10562271
- Publisher / Repository:
- Inter-Research Science Publisher
- Date Published:
- Journal Name:
- Marine Ecology Progress Series
- Volume:
- 738
- ISSN:
- 0171-8630
- Page Range / eLocation ID:
- 119 to 132
- Subject(s) / Keyword(s):
- Olympia oysters Ostrea lurida Urosalpinx cinerea Predation Intertidal zonation Refuge Restoration
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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NA (Ed.)The realized niche of many sessile intertidal organisms is constrained by different stressors that set boundaries for their distribution based on tidal elevation. Higher tidal elevation increases desiccation risk but can provide a refuge from predation. Conversely, deeper water increases feeding time and growth but also increases vulnerability to benthic predators. Eastern oysters Crassostrea virginica harden their shells in response to predator cues, which reduces their mortality from predation. We performed a field study to investigate if this defense mechanism could be manipulated to expand their realized niche and increase space for oyster survival and growth. We raised oysters in the presence of predators (blue crabs Callinectes sapidus) or in nopredator controls, measured changes in shell morphology, and then monitored oyster survival at different tidal elevations across 7 locations with different predator and salinity regimes. Oyster survival was significantly higher at the highest tidal elevations tested. Exposure to predators before deployment also significantly increased shell hardness and survival, with intertidal oysters experiencing greater improvement in survival from cue exposure than subtidal oysters. Intertidal placement (>15% exposure time) had larger effects on survival than predator exposure, but predator exposure increased oyster survival at all tidal elevations, suggesting that predator induction could help oysters both deter predators and resist abiotic stressors like desiccation, and perhaps increase the spatial areas where oysters can be restoredmore » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3354/meps14590
