fish assemblage structure indicates limited progress in...
TRANSCRIPT
Fish assemblage structure indicates limited
progress in restoration process over a
lustrum in a severely degraded estuary of
southern Tamaulipas, Mexico
Alejandro Fierro and Carlos Cintra
Fish assemblage structure indicates limited
progress in restoration process over a lustrum
in a severely degraded estuary of southern
Tamaulipas, Mexico
1) The estuary
2) Degradation
3) Restoration efforts
4) Ecosystem response
Estero Garrapatas
Garrapatas
Estero Garrapatas
• End part of Arroyo Garrapatas, permanently flowing
• Originally discharging in coastal lagoon open to Gulf of Mexico
• 4 mangrove spp– Red (dominant)
– Buttonwood
– Black
– White
Degradation
• Early 1970’s:
construction of ship
channel (minimal impact)
• 1978: construction of
pipeline+roadLevee
Pipeline/road
Degradation
• Culverts above high tide
• Tidal exchange
interrupted
• Estuary changed to
permanent freshwater
wetland
Restoration efforts
• 1996: designated
natural protected area
• 2003: seawater
discharge from power
plant
– 3 km detour to reach
estuary
Levee
Pipeline/road
Seawater
inlet
Restoration efforts
• 620 L/s of seawater
• 2-3 degrees warmer • Freshwater biota died
Restoration efforts
• 2005: mangrove
reforestation attempted
but abandoned
Restoration efforts
• 2005: fishpass,
intermittently
functional
Restoration efforts
• 2007: dredging of lower
part
Levee
Pipeline/road
Seawater
inlet
Dredging
Ecosystem Response (mangrove)
• Mangrove stands
recovered rapidly,
• Successful passive
restoration of mangrove
Estero Garrapatas
Garrapatas
Estero Barberena
Monitoring of structural and
functional indicators
5 consecutive years
NBarberena
NN
levee
NGarrapatas North (GEN)
Garrapatas South (GES)
Monitoring methods
Monitoring methods
Group averageBA
R
GEN
GES
Sites
100
80
60
40
20
Sim
ilar ity
Resemblance: S17 Bray Curtis similarity
Ecosystem Response
(fish assemblages)
• Similarity among sites
Ecosystem Response
(fish assemblages)
• Assemblage similarity over time
Transform: Fourth root
Resemblance: S17 Bray Curtis similarity
Year2006
2007
2008
2009
2010
2006
2007
2008
2009
2010
2D Stress: 0
• Assemblages over time
Ecosystem Response
(fish assemblages)
0
1
2
3
4
5
6
7
8
9
2006 2007 2008 2009 2010
Nu
mb
er
of
Sp
ec
ies
Year
b)
0
0.5
1
1.5
2
2.5
2006 2007 2008 2009 2010
Div
ers
ity
Year
c)
Ecosystem Response
(fish assemblages)
aa
b
0
5
10
15
20
25
30
35
40
45
BAR GEN GES
Ab
un
dan
ce
Site
a
b
b
0
0.5
1
1.5
2
2.5
BAR GEN GES
Div
ers
ity H
Site
c)a
b
b
0
1
2
3
4
5
6
7
8
9
10
BAR GEN GES
Nu
mb
er
of
Sp
ecie
s
Site
b)
Dominance
Species Site
Archosargus probatocephalus BAR
Ariopsis felis BAR
Astyanax mexicanus GES
Brevoortia gunteri BAR, GEN, GES
Brevoortia patronus BAR
Caranx hippos BAR
Centropomus undecimalis BAR
Cyprinodon variegatus GEN, GES
Dormitator maculatus GES
Eleotris pisonis BAR
Elops saurus BAR
Eucinostomus argenteus BAR
Eugerres mexicanus BAR
Herichthys cyanoguttatus GEN, GES
Megalops atlanticus BA
Micropogonias undulatus BAR
Mugil cephalus BAR, GEN, GES
Mugil curema BAR, GEN, GES
Poecilia sp. GES
Oreochromis aureus BAR, GEN, GES
Ecosystem Response
(fish species)
• Only 3 estuarine
spp have
returned
• 6 legacy spp
remain including
exotic tilapia
-4 -2 0 2 4
PC1 (36.4% of the variation)
-2
0
2
PC
2 (
25
.2%
of
the
va
ria
tio
n)
Site_NameBAR
GEN
GESDO (mg/l)
Temperature (˚C)
Salinity (g/l)
Secchi Depth (cm)pH
Ecosystem Response
(fish assemblages)
• Driving variables � Salinity, DO
• Driving variables � Salinity, DO
Ecosystem Response
(fish assemblages)
a
b
b
10
15
20
25
30
35
40
BAR GEN GES
Sali
nit
y (
g/l
)
Site
c)
a
b
b
2
3
4
5
6
7
BAR GEN GES
DO
(m
g/l
)
Site
a)
27
28
29
30
31
BAR GEN GES
Te
mp
era
ture
(C
)
Site
b)
Conclusions
• Costly interventions funded by Port
administration and power plant
• Monitoring exceptionally comprehensive
• Total recovery of mangrove
• Partial recovery of aquatic habitat
• Excellent prognosis with additional
interventions (levee, fish pass)