provision of refuge volume by corals and simulation-based habitat equivalency analysis john w....
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Provision of Refuge Volume by Corals
and Simulation-Based
Habitat Equivalency Analysis
John W. McManus 1 and Lisa C. McManus 2
1 National Center for Coral Reef Research University of Miami
2 Department of Ecology and Evolutionary Biology Princeton University
Refuge Volume
xda-wallpapers.com
Steve Turek/Coral Reef Alliance Coral Reef Alliance
Requirements for Refuge
Volume Estimations
Estimation procedure should scale properly.
At a minimum, one should find a factor which is multiplied by a dimension cubed.
0 1 2 3 4 5 6 7 8 9 100
200
400
600
800
vol = cfd3
surf = cfd2
Dimension (e.g. radius)
Est
imat
e
Basic Shape Formulas Surface Area Volume
Square --
Cube
Circle --
Semicircle --
Cylinder (no ends)
Sphere
Spherical Wedge
Not used
Hemisphere (no bottom)
Growth Form Surface Area Refuge Volume
Branching
Columnar Small <10 cm
Columnar Large 10+ cm
Disc-Solitary NA
Encrusting NA
Foliose
Massive
Plate
Table
Mixed Plate-Column(such as often in
Porites rus)
Application of Refuge
Volume Estimationl Apra Harbor Guam will have
dredging impacting up to 1 sq. km of reef area – the largest US reef mitigation case so far.
l The map shows refuge volume available due to corals (larger circles mean more volume).
l Evaluation of substrate and other HAB contribution to local refuge volume is underway.
This information is being used to minimize
impacts and establish mitigation goals.
98 33 76 95 50 32 41 80 18 3 45 101 97 39 10 59 20 100 94 93 90 14 4 29 96 91 71 30 86 84 99 19 700
10
20
30
40
50
Bottom Cover
Site No.
m2
98 33 76 95 50 32 41 80 18 3 45 101 97 39 10 59 20 100 94 93 90 14 4 29 96 91 71 30 86 84 99 19 700
100
200
300
400
500
600
Surface Area
Site No.
m2
98 33 76 95 50 32 41 80 18 3 45 101 97 39 10 59 20 100 94 93 90 14 4 29 96 91 71 30 86 84 99 19 700
0.51
1.52
2.53
3.5
Refuge Volume
Site No.
m3
DigiReef for Habitat
Equivalency Analysis
(HEA)
Problems with Assuming
Linear Recovery
1 2 3 4 5 6 7 8 9 10 11 12 13 14 150
20
40
60
80
100
120
Years
Pe
rce
nt
Se
rvic
e V
alu
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a
b
Simulation Parameters
l Coral growth rateu Used literature values
l Coral rate of instantaneous mortalityu Applied catch curves to size data by species and form
u Where necessary, combined similar species
l Coral rate of annual recruitmentu Used simple virtual population analysis
l Colony maximal dimensionu Based on maximal sizes in the site
Estimating Rates of Mortality
Estimating Rates of Mortality
Estimating Annual Recruitment
Age in Years or Radius in CentimetersYear 1 2 3 4 5 6 7 8 9 102001 100 61 37 22 14 8 5 3 2 12002 100 61 37 22 14 8 5 3 2 12003 100 61 37 22 14 8 5 3 2 12004 100 61 37 22 14 8 5 3 2 12005 100 61 37 22 14 8 5 3 2 12006 100 61 37 22 14 8 5 3 2 12007 100 61 37 22 14 8 5 3 2 12008 100 61 37 22 14 8 5 3 2 12009 100 61 37 22 14 8 5 3 2 12010 100 61 37 22 14 8 5 3 2 1
Empirical: 1000 610 370 220 140 80 50 30 20 10
DigiReef Inputs: Site 93
Recruitment (settled corals per year) Battle skill (relative hierarchy) Growth rate (cm / y) Instantaneous mortality Volume factor Maximum radiusPavona decussata 3 1 4 0.127 0.393 20 Pocillopora damicornis 2 2 3 0.12 0.126 20 Porites cylindrica 2 3 3 0.025 0.126 10 Porites lutea 1 4 2 0.122 0.011 20 Porites rus 1 3 2 0.027 0.21 30
Color SpeciesBlue Pavona decussataRed Pocillopora damicornisYellow Porites cylindricaViolet Porites luteaOrange Porites rus
Simulated Regrowth: Site 93
0 20 40 60 80 100 1200
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800
10000 20 40 60 80 100 120
0
500
1000
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2000
0 20 40 60 80 100 1200%
20%
40%
60%
80%
0 20 40 60 80 100 1200
50
100
150
200Individuals per species
Spectra of sizes of massive corals( Porites lutea )
Spectra of refuge volumes
Total coral cover
Years of simulated regrowth
Ma
nh
att
an
Me
tric
Dis
tan
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Pe
rce
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Co
ral
Co
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r
Ma
nh
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Me
tric
Dis
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Conclusions I
l Refuge volume is an important metric for quantifying ecosystem function.
l It can be associated with corals, other habitat structuring benthos, and the substrate itself.
l It is not necessarily well correlated with coral cover or surface area indices.
l Estimation procedures still require improvements from field and laboratory measurements.
Conclusions II
l DigiReef simulation can improve the basis for the determination of compensatory requirements in mitigation cases.
l Coral mortality and recruitment can be roughly approximated via fishery analytical methods.
l For one particular site, the original coral cover and size spectra of massive corals was optimally achieved, and community structure was nearly optimally achieved, within 40 years.
l The spectrum of available refuge volumes was replicated within 8 years, because most was due to small branching and foliose coral colonies. These results will vary in different coral communities.
Acknowledgements
Our thanks to:u Deborah Shafer and others at the US Army Corps
of Engineers, Engineer Research and Development Center.
u US Navy, NOAA, US EPA, Gov. Guam, others, especially Steve Kolinski
u HDR-EOC and CSA International Consultancy Firms
u Dr. Yimnang Golbuu and others for field work
Thank you.