Tape Grass, Eel Grass, Wild Celery
(Vallisneria americana)
Indicator of Caloosahatchee Ecosystem
Health
By David W. Ceilley
Johnson Engineering Inc.
Acknowledgements
Funding Partners
SFWMD, Peter Doering, Beth Orlando, Teresa Coley
WCIND & Lee County Marine Services
Other Partners
SCCF: Steve Bortone, Eric Milbrandt, Rick Bartleson
Conservancy of SW Florida, Ian Bartoszek, Melinda
Schuman, Glen Buckner,
John Cassani and Lee County Hyacinth Control
FGCU Faculty and Staff
Edwin M. Everham, III, John A. Ferlita, Kory M. Ross, Geoff
Rosenaw, Connor Ceilley, Daniel Dickenson, and Serge
Thomas
Ecosystem Services of Vallisneria
Habitat for fishes, crabs, shrimp, crayfish, bivalves,
epiphytes, and numerous aquatic insects
Forage for endangered manatees, freshwater
turtles, waterfowl, fish, crayfish and snails
Stabilizes sediments, attenuates wave action,
improves water clarity, and removes nutrients
North Florida Springs & Rivers
South Florida Upper Estuaries
Why is Vallisneria americana a good
indicator?
1. Tolerant of oligohaline conditions (<
10ppt), natural fluctuations in water
chemistry, sediments, and nutrients in
upper estuaries.
2. Historically important and considered as
a Valued Ecosystem Component (VEC) in
Caloosahatchee Ecosystem (Barnes 2005)
3. Once covered over 1,000 acres in the
upper Caloosahatchee Estuary: Whiskey
Creek to I-75 (Hoffacker 1998)
4. Sensitive to Anthropogenic disturbances,
extreme unnatural salinity regimes
5. Can respond quickly when conditions are
restored (Lake Trafford & FGCU studies)
Factors controlling growth and
distribution of Vallisneria:
1. Salinity levels and duration of exposure
(Doering and Chamberlain 2000).
2. Water clarity, light attenuation, color
(Bortone and Turpin 2000)
3. Sediment type, nutrient concentrations,
and genetic strains (Gettys and Haller
2011)
4. Herbivory (Ceilley and Bortone 2003,
SCCF 2008, Ceilley 2009, Moore et al.
2010, Ceilley and Everham 2012)
Figure 1. Submerged aquatic vegetation (SAV)
map of the Caloosahatchee Estuary prepared
by Hoffacker 1994 using 1993 data.
Previous Work
Circular Exclosures deployed in Tidal
Caloosahatchee 2002 & Lake Trafford 2008
Center of circular
exclosure plot from
2009 WCIND pilot
study on cage
design after two
years in June 2011
2-year old exclosure (Oxbow site 1)
Lake Trafford Planting Site in 2012
Caloosahatchee River
Tape Grass Restoration Project
South Florida Water Management District &
FGCU Ecology Lab: June 2011 to Dec 2012
Goal & Objectives: Phase 1
Small 1-m³ Exclosure Study
• Establish Vallisneria americana seed stock in the
upper Caloosahatchee R.
• Evaluate planting density(10/m² vs. 20/m²)
• Evaluate two local genetic strains for growth in
the Caloosahatchee R.
• Compare two sites: protected oxbow with high
organics and open sandy shoreline area
Project Details
Site
Density
Source
High
(20/m2)
Lake T (3)
Low
(10/m2)
High
(20/m2)
Low
(10/m2)
Lake K (3)
Lake T (3)
Lake K (3)
Lake T (3)
Lake K (3)
Lake T (3)
Lake K (3)
Project Details
Invasive exotic apple snail, Pomacea insularum
Phase II: Large Cage Experiments May –Dec 2012
Salinity
0.6
Salinity (ppt)
0.5
Site 1
0.4
Site 2
Site 3 (Reference)
0.3
Site 4
0.2
Site 5
Site 6
0.1
0
3/6/2012
Site 7
4/6/2012
5/6/2012
6/6/2012
7/6/2012
8/6/2012
Date
1.8
Secchi (m)
1.6
Depth (m)
1.4
1.2
1
0.8
Site 1
0.6
Site 2
0.4
Site 3 (Reference)
0.2
0
3/6/2012
Site 4
4/6/2012
5/6/2012
6/6/2012
Date
7/6/2012
8/6/2012
Site 5
Site 6
Site 7
Table 1. Mean % cover and mean # shoots/m² for large exclosures on
August 22, 2012 (< 90 days)
Site
% Cover # Shoots/m²
Site # 6 Lake Kennedy
100%
119
Site # 6 Lake Trafford
94%
36
Site # 5 Lake Kennedy
98%
92
Site # 5 Lake Trafford
96%
56
Site # 4 Lake Kennedy
100%
68
Site # 4 Lake Trafford
96%
23
Site # 7 Lake Kennedy
93%
33
Site # 7 Lake Trafford
96%
30
Conclusions:
• Herbivory is controlling factor both upstream and
downstream of Franklin Locks
• “Using mesh exclosures to protect the plants from
herbivory was critical to restoration success.” Moore et al.
2010 Restoration Ecology Volume 18, Issue 4, pp 596–604
• Exclosure cages allowed for seed production.
• Vallisneria plants outside the cages were grazed &
short (2-3cm). No flowering or seed pods
observed during the study
• Growth habits of 2 strains differed:
Lake Trafford = larger plants but fewer
Lake Kennedy = smaller and more numerous
Questions?
Problems Encountered Phase II: Large Cages 2012
•
Damage to cages as a result of vandalism and/or extreme wave action.
Solution: reinforced cages with PVC and add rebar to the bottom of the Vexar mesh.
•
The large wakes (4-5’ high) by large vessels traversing the main channel.
Proposed Solutions:
1. Develop large, soft dome-shape cage design that is flexible to absorb waves
2. Use heavy duty metal or stainless cages (J. Anderson design)
3. Create SAV founder colony areas in tributaries, oxbows ,embayment areas
•
Herbivory by non-native apple snails, Pomacea insularum
Proposed Solutions:
1. Eradicate egg masses and remove adult snails during routine maintenance
2. Leave cages open on top with perches for limpkins and snail kites
3. Experiment with cage designs and chemical deterants
•
Damage to cages and herbivory by Manatees and Pseudemys spp. Turtles
1. Delist manatees and declare open season on turtles (just kidding )
2. Plant large founder colonies for large plantings
3. Use hardened anchored small cages (J. Anderson type) for dockside projects