Intertidal Vegetation Dynamics in the Tampa Bay Estuary

Home | Tampa Bay Study | 2nd Annual Science Conference | Posters | Intertidal Vegetation Dynamics in the Tampa Bay Estuary

Gulf of Mexico Estuaries Integrated Science

View other reports pertaining to Ecosystem Function & Structure

Ecosystem Structure
& Function

Tampa Bay Pilot Study 2002 Poster Series

Geology & Geomorphology

Water & Sediment

Wetlands

Seagrass

Intertidal Vegetation Dynamics in the Tampa Bay Estuary

T.J. Smith III1, N. Silverman2, Jeffrey Dismukes2, G. Peery2, W. Weaver2
1: USGS/Geological Discipline
2: ETI Professionals, Inc.

Results & Discussions:

Visual observations of all plots have been completed along with quantitative re-sampling at several plots. Recruitment by mangrove stems into the plots was extremely low. Growth has also been very slow. However, increases in DBH have been measured in two plots near the mouth of the Alafia River (plots AT4 and AT4B, see Figure 1B). Both plots are dominated by small stemmed individuals of all species. DBHs are less than 6.0 cm in AT4 and less than 3.5 cm in plot AT4B. However, over the course of a year, increases in DBH were measured in both plots, especially for Laguncularia at these plots (Figures 4a,b,c,d). Significant mortality was observed at Moses Hole in the Terra Ceia Preserve. The two largest stems (one 6.0 cm the other 8.5 cm) in plot MHNC-D1 were killed by a severe winter storm in January (Figure 4e,f).

We recognize that two consecutive measurements are not enough to make strong inferences concerning environmental changes in the plots. However, the utility of starting a longer term sampling program in the wetlands of Tampa Bay has been clearly demonstrated by studies in coastal ecosystems elsewhere (Putz & Chan 1986; Smith et al., 1994; Bell 1997).

Click images to view enlargements.

Fig. A: Alafia River Site #AT4
First Year Survey (2001)
Plot of Diameter at Breast Height vs. Position (n=45)
Laguncularia: (mean DBH = 1.93 cm)
Avicennia: (mean DBH = 3.28 cm)

Fig. B: Alafia River Site #AT4
Second Year Survey (2002)
Plot of Diameter at Breast Height vs. Position (n=45)
Laguncularia: (mean DBH = 1.96 cm)
Avicennia: (mean DBH = 3.36 cm)

Fig. C: Alafia River Site #AT4B
First Year Survey (2001)
Plot of Diameter at Breast Height vs. Position (n=77)
Rhizophora: (mean DBH = 1.70 cm)
Laguncularia: (mean DBH = 1.96 cm)
Avicennia: (mean DBH = 1.21 cm)

Fig. D: Alafia River Site #AT4B
Second Year Survey (2002)
Plot of Diameter at Breast Height vs. Position (n=77)
Rhizophora: (mean DBH = 1.71 cm)
Laguncularia: (mean DBH = 1.99 cm)
Avicennia: (mean DBH = 1.24 cm)

Fig. E: Terra Ceia Preserve Site #MHNC-D1
First Year Survey(2001)
Plot of Diameter at Breast Height vs. Position (n=52)
Rhizophora
Laguncularia
Avicennia

Fig. F: Terra Ceia Preser e Site #MHNC-D1 Second Year Observation (2002)

Fig. F: Terra Ceia Preserve Site #MHNC-D1
Second Year Observation (2002)
Plot of Diameter at Breast Height vs. Position(n=50)
Rhizophora
Laguncularia
Avicennia

Figure 4: For both plot sites AT4 and AT4B in the Alafia River Study Area, the second year survey indicates slight growth amongst the adult trees with no emergent growth in the plot areas. At AT4 the calculated mean DBH for Avicennia increased from 3.28 cm in 2001 to 3.36 cm in 2002. Calculated mean DBH for Laguncularia at the same site increased from 1.93 cm in 2001 to 1.96 cm in 2002.

There were no Rhizophora species in the AT4 plot. At AT4B, calculated mean DBH increased from 1.21 cm in 2001 to 1.24 cm for the Avicennia species. Calculated mean DBH for Laguncularia increased from 1.96 cm in 2001 to 1.99 cm in 2002. The Rhizophora species at AT4B also showed a net increase in calculated mean DBH from 1.7 cm in 2001 to 1.71 cm in 2002.

The final two plots from the MHNC-D1 site in the Terra Ceia Preserve show the result of damage from a severe winter storm in January 2002, which toppled two of the largest Laguncularia at this site, circled in the plot from the first year survey.