Marine Biology Journal - Supplementary material
Controls of the distribution and composition of sea urchin assemblages on Brazilian
subtropical rocky reefs
C. A. M. M. Cordeiro1, A. R. Harborne2and C. E. L. Ferreira1
(1) Laboratório de Ecologia e Conservação de Ambientes Recifais, Departamento de Biologia
Marinha, Universidade Federal Fluminense (UFF), Caixa Postal 100644, CEP 24001-970, NiteróiRJ, Brazil
(2) Marine Spatial Ecology Laboratory and Australian Research Council Centre of Excellence for
Coral Reef Studies, School of Biological Sciences, Goddard Building, The University of
Queensland, Brisbane, QLD 4072, Australia
Correspondingauthor: Cordeiro, C.A.M.M.
cammcordeiro@id.uff.br
Address: Departamento de Biologia Marinha, Universidade Federal Fluminense (UFF), Caixa Postal
100644, Niterói-RJ 24001-970, Brazil
Tel: +55 (21) 26292261, Fax:+55 (21) 26292292
Substrate cover
Fig. 1s Comparative percent cover of benthic morpho-functional groups between western and eastern
sites across depth. ACA – articulated coralline algae, CCA – crustose coralline algae, EAM –
Epilithic algal matrix
Exposure
Briefly, online wind data archives (BDMEP, 2013) from a land based meteorological station
located at Arraial do Cabo, were analyzed to calculate the mean wind speed in eight 45° segments,
and the proportion of time the wind blew from within each segment (see Online Resource Table 1s).
The fetch was then calculated in each of eight directions (the central point of each segment, namely
0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°), and these fetches were combined with the depth of
each survey at each site and the appropriate linear wave energy equations to calculate wave energy
in each direction. Total wave energy for each depth strata at site scale was calculated as the sum of
these eight values, after each had been weighted by the proportion of time the wind blew from that
segment.
Table 1s Resumed values of wind data from Arraial do Cabo (Brazil)
from January 2010 to February 2013
Wind speed
(mean ±s.d.)
N
0.01
2.55 ± 0.07
NE
0.23
3.90 ± 3.11
E
0.40
4.95 ± 2.30
SE
0.09
3.05 ± 1.65
S
0.03
2.11 ± 1.17
SW
0.03
1.65 ± 0.93
W
0.17
2.78 ± 1.43
NW
0.04
2.11 ± 1.17
PTWD - proportion of time the wind blew from within each
direction. Wind speed is shown in m.s-1
Direction
PTWD
Exposure values (1–6m) varied significantly among sites to the east (1–4;
mean±SE=0.003±0.001 J m-3, n=24) and west (5-8; mean±SE=0.41±0.06 J m-3, n=24) of the
isthmus (t-test, t24=-2.63, p=0.015).
Expoure (J m-3 )
10
1
0.1
0.01
0.001
et
ud
o
ar
So
m
So
n
le
se
s
In
g
es
es
Fr
an
c
rc
os
Po
Ab
o
br
in
ha
An
eq
ui
m
M
ar
am
ut
á
0.0001
Fig. 2s Wave exposure values calculated for the first meter at studied sites in Arraial do Cabo, RJ.
Gray bars represent eastern sites and black bars western sites. Note that the x-axis is in logarithmic
scale.
100
90
80
70
60
50
40
30
20
10
0
East
hy
st
rix
us
an
Di
od
on
ho
la
c
sp
on
Di
od
yc
Ch
ilo
m
th
su
s
in
o
ng
id
e
ro
eo
Sp
h
te
ru
s
ss
pe
isp
is
h
le
p
no
ha
St
ep
le
ri
s
id
u
tu
la
ve
uf
us
lis
te
s
sr
Ba
Bo
di
pu
l ch
an
u
ey
i
Bo
di
an
ho
us
er
es
po
nt
eu
ge
ar
Ha
lic
us
Di
pl
od
el
us
West
s
Biomass (%)
Potential predators
Fig. 3s Relative contribution of biomass of potential predator species according to side of the isthmus
at rocky reefs in Arraial do Cabo, RJ.
Sea urchin size and biomass
Data on size and biomass was analyzed using ANOVA after log+1 transformation.
Correlations between size and biomass values were tested using Pearson correlation index. Mean size
and mean biomass values differ among species. Echinometra lucunter presents highest values for
both variables (Table 2s), followed by Arbacia lixula and Paracentrotus gaimardi. The correlations
between size and biomass values for all three species are high (Figures2s to 4s), which indicates that
the parameters found could be used for extrapolation of values of urchin biomass for the Arraial do
Cabo region.
Table 2s Descriptive data on size and biomass values of dominant urchin species found in Arraial
do Cabo, RJ, Brazil. Means with the same letter are not significantly different (p<0.05)
n
Arbacia lixula 205
Echinometra lucunter 200
Paracentrotusgaimardi 201
Size
(mm)
s.d.
23.87 a 8.15
35.17 b 16.57
15.57 c 5.06
min. max.
0.7 50.2
9.2 68.9
5.2 29.6
Biomass
(g)
s.d.
10.02 a
10.46
48.26 b
55.01
2.88c
2.33
min.
max.
0.05 57.73
0.53 218.38
0.13 12.11
Fig. 4s Scatterplot and regression line of size (test diameter - mm) against biomass (g) for
Echinometra lucunter. Displayed equation is back-transformed to simplify interpretation
Fig. 5s Scatterplot and regression line of size (test diameter - mm) against biomass (g) for Arbacia
lixula. Displayed equation is back-transformed to simplify interpretation
Fig. 6s Scatterplot and regression line of size (test diameter - mm) against biomass (g) for
Paracentrotus gaimardi. Displayed equation is back-transformed to simplify interpretation
Interactions in models
The predicted values for each tested factor were obtained using the function predict of
package stats (R software). When an interaction was detected, a two-stage procedure was taken: one
factor was considered as a base and the factor to be tested as constant. The tested factor had its
values held constant at high and low values. These values were based on 10% of the maximum value
of each variable for low constant values (e.g. shallow, low number of crevices), and 90% of
maximum value for high constant values. The base factor was generated as a sequence of numbers
within the range of values observed for this factor. Finally, the predicted values were plotted against
the base values in order to observe trends according to scenarios were only one of the factors is
variable.
Density (n 0.25 m-2)
3
> crevices
< crevices
2.5
2
1.5
1
0.5
0
West
East
Fig. 7s Predicted values for density of Paracentrotus gaimardi (>5cm) in interaction scenarios of
high and low values number of crevices on both east and west of the isthmus.
Density (n 0.25 m-2)
30
25
deep
shallow
20
15
10
5
0
West
East
Fig. 8s Predicted values for density of Echinometra lucunter (<2cm) in interaction scenarios of high
and low values of depth on both east and west of the isthmus
Density (n 0.25 m-2)
5
4
deep
shallow
3
2
1
0
West
East
Fig. 9s Predicted values for density of Echinometra lucunter (2-5cm) in interaction scenarios of high
and low values of depth on both east and west of the isthmus
Density (n 0.25 m-2)
5
4
deep
shallow
3
2
1
0
West
East
Fig. 10s Predicted values for density of Echinometra lucunter (>5cm) in interaction scenarios of high
and low values of depth on both east and west of the isthmus