distribution of seagrass beds along the texas coast chris wilson marine science institute
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Distribution of Seagrass Beds Along the Texas Coast
Chris WilsonMarine Science Institute
Introduction
• Who – UTMSI and TXCEQ
• Goal – Determine the factors controlling seagrass distributions along the TX coast
• How- Use of GIS and Time Series Data
Study Location
Data Aquisition
Light Decreasing with Depth
R2 = 0.9644
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
depth (m)
% S
I
Light and Seagrass Cover
Avg Bare vs %SI
0.00
20.00
40.00
60.00
80.00
100.00
120.00
0.00 20.00 40.00 60.00 80.00
%SI
% B
are
Depth and Total Seagrass Cover
Total Cover vs Depth
0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00
100.00
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
depth (m)
% c
over
Seagrass Cover and Location
• Red = 0% Cover
• Orange < 50% Cover
• Green > 50% Cover
2003-2004 Decline in Thalassia
%Thalassia Cover Vs Time
0.00000
20.00000
40.00000
60.00000
80.00000
100.00000
120.00000
AveT02 avet03 avet03s avet04 avet05 avet05s
Time
% C
over
2003-2004 Decline in Seagrass Cover
Total Seagrass Cover Over Time
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
2002w 2003w 2003s 2004w 2005w 2005s
Sampling Date
Ave
rag
e C
ove
r (%
)
Yearly Average Rainfall For Texas
Yearly Precipitation
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
2002Precip 2003Precip 2004 Precip 2005Precip
Pre
cip
itation (in
ches)
Summer Rainfall- Corpus Christi
Total Summer Precip Over Time
0123456789
10
Year 2002 Year 2003 Year 2004 Year 2005
Time
Pre
cip
(in
ch
es)
Monthly Rainfall – Corpus Christi
May Precip Over Time
0123456
Year 2002 Year 2003 Year 2004 Year 2005
Time
Pre
cip
(in
ches
)
July Precip Over Time
0
1
2
3
4
5
Year 2002 Year 2003 Year 2004 Year 2005
Time
Pre
cip
(in
ches
)
June Precip Over Time
0
1
2
3
4
Year 2002 Year 2003 Year 2004 Year 2005
Time
Pre
cip
(in
ches
)
August Precip OVer Time
0
0.5
1
1.5
2
Year 2002 Year 2003 Year 2004 Year 2005
Time
Pre
cip
(in
ches
)
Decline >20% Quadrat Cover
Conclusions
• Light and depth affect the distribution of seagrass beds
• More work needs to be focused on seagrass beds between 1 and 1.5m in depth
• Decline in seagrass cover may have been attributed to rainfall, but more data is needed
References
• http://jrscience.wcp.muohio.edu/FieldCourses00/MarineEcologyArticles/SeagrassEcosystems.html
• http://www.srh.noaa.gov/crp/climate/crpf-6.html