scholarly journals Modeling Oyster Reef Restoration: Larval Supply and Reef Geometry Jointly Determine Population Resilience and Performance

2021 ◽  
Vol 8 ◽  
Author(s):  
Romuald N. Lipcius ◽  
Yi Zhang ◽  
Jingyi Zhou ◽  
Leah B. Shaw ◽  
Junping Shi

Restoration of native oyster (Crassostrea virginica) populations in Chesapeake Bay shows great promise after three decades of failed attempts. Population models used to inform oyster restoration had integrated reef habitat quality, demonstrating that reef height determines oyster population persistence and resilience. Larval recruitment drives population dynamics of marine species, yet its impact with reef height and sediment deposition upon reef restoration is unknown. To assess the influence of reef height, sediment deposition and larval supply, we adapted a single-stage population model to incorporate stage structure using a system of four differential equations modeling change in juvenile density (J), and changes in volume of adults (A), oyster shell reef (R), and sediment (S) on an oyster reef. The JARS model was parameterized with empirical data from field experiments. Larval supply included larvae from the natal population and from outside populations. The stage-structured model possessed multiple non-negative equilibria (i.e., alternative stable states). Different initial conditions (e.g., oyster shell reef height) resulted in different final states. The main novel findings were that the critical reef height for population persistence and resilience was jointly dependent on sediment input and larval supply. A critical minimum larval supply was necessary for a reef to persist, even when initial sediment deposition was zero. As larval supply increased, the initial reef height needed for reef persistence was lowered, and oyster reef resilience was enhanced. A restoration oyster reef with higher larval influx could recover from more severe disturbances than a reef with lower larval influx. To prevent local extinction and assure a positive population state, higher levels of larval supply were required at greater sediment concentrations to overcome the negative effects of sediment accumulation on the reef. In addition, reef persistence was negatively related to sediment deposited on a reef prior to larval settlement and recruitment, implying that restoration reefs should be constructed immediately before settlement and recruitment to minimize sediment accumulation on a reef before settlement. These findings are valuable in oyster reef restoration because they can guide reef construction relative to larval supply and sediment deposition on a reef to yield effective and cost-efficient restoration strategies.

2017 ◽  
Vol 20 (1) ◽  
Author(s):  
Melissa W Southwell ◽  
Jessica J Veenstra ◽  
Charles D Adams ◽  
Elizabeth V Scarlett ◽  
Kristy B Payne

2014 ◽  
Vol 89 ◽  
pp. 20-28 ◽  
Author(s):  
Megan La Peyre ◽  
Jessica Furlong ◽  
Laura A. Brown ◽  
Bryan P. Piazza ◽  
Ken Brown

1986 ◽  
Vol 43 (11) ◽  
pp. 2072-2084 ◽  
Author(s):  
G. P. Ennis

A review of the literature pertaining to stock definition, causes of variability in recruitment to standing stocks, and larval recruitment processes in the American lobster, Homarus americanus, is presented. Several stocks can be identified but their boundaries are indistinct. The areas are too large for consideration of any of the stocks as a single management unit. The bulk of annual landings is composed of recruitment to standing stocks since the preceding fishing season. Landings for all areas fluctuate and there is considerable variability in patterns of fluctuations between areas. Suggested causes of variability in recruitment include variation in temperature, variation in annual river discharge, fishery induced variability in egg production, man-made interruption in larval supply, and ecosystem change. Mechanisms that determine where larvae that originate in a given area eventually settle are uncertain. Literature on larval recruitment processes contains theories based on passive transport of larvae by surface currents and others based on interacting behavioral and hydrographic mechanisms that may enable larvae to maintain position near parental grounds.


2006 ◽  
Vol 54 (6-7) ◽  
pp. 109-117 ◽  
Author(s):  
J.-L. Bertrand-Krajewski ◽  
J.-P. Bardin ◽  
C. Gibello

This paper presents continuous field experiments carried out during 4 years in a man-entry egg-shaped combined sewer in Lyon, France in order to contribute to the knowledge and the modelling of sediment accumulation and sediment removal by means of a Hydrass flushing gate. The 250 μm sediments are mainly mineral, and their physical and chemical characteristics appear as rather stable in time and space. Long-term sediment monitoring reveals: i) a regular asymptotic increase of both the sediment mass and the slope of its longitudinal profile, ii) a clear correlation between local sediment profile irregularities and sewer ancillaries but without significant influence on the global and long term accumulation. Simple sediment accumulation modelling shows: i) a good suitability of a three parameters conceptual model to reproduce asymptotic sediment volume accumulation, and ii) a good suitability of the Velikanov model to reproduce sediment profiles. Both models reproduce observations with an acceptable margin of uncertainty for operational management purposes but are very sensitive to input data and parameter values. The Hydrass flushing gate is efficient and it appeared that the mass of sediments moves downstream linearly with the number of flushes.


2010 ◽  
Vol 33 (6) ◽  
pp. 1355-1364 ◽  
Author(s):  
Rochelle Plutchak ◽  
Kelly Major ◽  
Just Cebrian ◽  
C. Drew Foster ◽  
Mary-Elizabeth C. Miller ◽  
...  

2017 ◽  
Author(s):  
Ricardo A Scrosati ◽  
Julius A Ellrich

Recruitment is a key demographic step for population persistence. This paper focuses on understanding barnacle (Semibalanus balanoides) recruitment. In rocky intertidal habitats from the Gulf of St. Lawrence coast of Nova Scotia (Canada), winter ice scour is common. At the onset of intertidal barnacle recruitment in the spring, mostly only adult barnacles and bare substrate are visible at high elevations on the shore. We conducted a multiannual study to investigate if small-scale barnacle recruitment could be predicted from the density of pre-existing adult barnacles. In a year that exhibited a wide adult density range (ca. 0–130 individuals dm-2), the relationship between adult density and recruit density (referred to the available area for recruitment, which excluded adult barnacles) was unimodal. In years that exhibited a lower adult density range (ca. 0–40/50 individuals dm-2), the relationship between adult and recruit density was positive but simply resembling the lower half of the unimodal relationship. Overall, adult barnacle density was able to explain 26–40 % of the observed variation in recruit density. The unimodal adult–recruit relationship is consistent with previously documented intraspecific interactions. Between low and intermediate adult densities, the positive nature of the relationship relates to the ability of adult barnacles to attract settlement-seeking larvae, likely enhancing local population persistence where it is most needed. Between intermediate and high adult densities, where population persistence may be less compromised and the abundant adults may be detrimental to recruit growth, the negative nature of the relationship suggests that larvae are stimulated to settle elsewhere. This unimodal pattern may be particularly common on shores with moderate rates of larval supply to the shore, as high larval supply rates may swamp the coast with settlers, decoupling recruit density from local adult abundance.


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