Dr. Wiley Kitchens. University of Florida USGS Florida Cooperative Fish and Wildlife Research Unit

Transcription

1 Tidal Wetland Studies Part I: Tide Gate Era Dr. Wiley Kitchens University of Florida USGS Florida Cooperative Fish and Wildlife Research Unit

2 PRE TIDE GATE ERA MARSH AREAS SAVANNAH NWR GEORGIA/ TOTAL S. CAROLINA EAST COAST FRESH TIDAL MARSH 23, , , (acres) SALT MARSH , ,630 (acres) % TIDAL FRESH MARSH %OFEASTCOAST TIDAL FRESH MARSH %OFGA/SC TIDAL FRESH MARSH

3 OBJECTIVES To examine the effects of the Savannah River tide gate and the hydrological regime of the Savannah River system. To determine how salinities were affected throughout the system. To identify what those effects meant to tidal wetlands throughout the system.

4 Synoptic Annual Decades

5 Freshwater Site Intermediate ed Site Brackish Site Subsaline Site

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7 SALINITY i ENVIRONME ENTAL SUIT TE SOIL TYPE i FLOODING i DISTANCE FROM HABITAT i EXISTING VEGETATION i etc SALINITY SOILS HYDROLOGY PROXIMITY VEGETATION GEOGRAPHIC INFORMATION SYSTEM MULTIVARIATE STATISTICAL ANALYSIS NEXT i FOR I=1, N PREDICTED HABITAT WHERE DOES PREDICTED HABITAT OCCUR?

8 Savannah Modeling Variables

9 Savannah Modeling Results

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11 Fresh Site 6 species A. keisak 7 species P. capillaceum Carex spp. T. latifolia P. cordata L. virginica M. scandens S. latifolia E. montevidensis G. tinctorium L. virginica P. cordata M. scandens S. latifolia 7 species A. keisak A. elliottii E. montevidensis A. elliottii S. validus Z. miliacea S. validus Z. miliaceae Interme ediate Site Osmunda sp. T. latifolia E. quadrangulata E. montevidensis Z. miliaceae S. robustus 4spp spp. Sagittaria spp. S. alterniflora A. elliottii Typha spp. E. montevidensis Z. miliaceae S. validus S. validus

12 S. latifolia T. angustifolia Z. miliaceae S. alterniflora Br rackish Site S. validus Z. miliacea T. angustifolia S. validus Subsalin ne Site S. alterniflora S. robustus A. tenuifolius S. validus T. angustifolia S. alterniflora T. angustifolia S. robustus Z. miliaceae S. validus

13 Mean Interstitial Salinity (ppt) Jun-93 Freshwater Oct-93 Intermediate Brackish Subsaline

14 Tidal Wetland Studies Part II: Harbor Deepening

15 Tidal Wetland Studies Part III: Current Research 1. Continued Vegetation Monitoring 2. Transplanting Experiments 3. Continued Salinity Monitoring 4. Salinity Spatial Synoptic 5. Tidal Swamp Study (Gap Analysis) 6. Sediment Characterization/Mapping (Synoptic spatial analyses) 7. Vegetation Change Analysis 8. Marsh Succession Model Development Support 9. Migratory Bird Study 10. Fish and Other Nekton Species Utilization of the Different Marsh Types

16 Task 1. Continued Vegetation Monitoring OBJECTIVES: To determine the composition and distribution of plant species in the lower Savannah River delta. Bi-annual sampling has been conducted during early and late growing season since Fall Monthly sub-sampling of 1 transect (3 points) per site has been conducted since January Vegetation data is being collected at four historical and three new marsh sites. Utilizing methods and sites from the 1990 and 1994 studies Utilizing methods and sites from the 1990 and 1994 studies to facilitate direct comparison to the earlier data.

17 Seven marsh sites are established with 18 sampling points each (126 total). One new fresh site off the Front River. Two new sites in the intermediate zone of the Middle River. Four historical sites along the salinity gradient of the Back River.

18 Each site consists of 6 transects with 3 sampling points per transect (total 18 points per site). Each sampling point is equipped with a double nested Each sampling point is equipped with a double-nested pvc well and marked with a 10 ft pvc pole.

19 Aboveground vegetation, interstitial salinity and soil samples are taken at each sampling point.

20 Plant samples are sorted by species, stems counted, dried and weighed for biomass. Relative importance values are then calculated for each species at each point.

21 B1M6 120 B1M B1M B1M1 50 B1M B1M5 0 B2M3 B2M4 B2M2 B2M1 B2M5 B3M4 B3M1 B2M6 B3M3 B3M2 B3M6 B3M5 B4M5 B4M6 B4M4 B4M1 B4M3 B4M2 Detrended Correspondence Analysis is used to ordinate the vegetation data These groupings are then classified into vegetation associations using Two Way INdicator SPecies Analysis (TWINSPAN). Canonical Correspondence Analysis will be used to examine the relationship Canonical Correspondence Analysis will be used to examine the relationship between vegetation classes and environmental variables such as interstitial salinity, elevation, sediment, and distance from creeks.

22 Task 2. Transplanting Experiments OBJECTIVE: To determine if location along the salinity gradient results in different species composition. Reciprocal transplant experiments were initiated in January Four transplant plots were randomly located within each of the four Back River sites.

23 Donor sites were established along the monthly sampling transects at each of the four Back River sites. Sixteen 0.25 m 2 slabs were extracted from each donor site, and randomly assigned to a transplant plot.

24 Location within the transplant plot was also randomly assigned. Each of the resultant transplant plots consist of four subplots, each representative of a different donor site.

25 Vegetation responses aremonitoredona a seasonal basis in a non-destructive manner. June 2001 sampling has been conducted and is awaiting analysis.

26 Task 3. Continued Salinity Monitoring OBJECTIVE: To document the changes in interstitial salinity levels of the lower Savannah River delta. YSI 600 XLM data sondes have been permanently installed at each of the seven en marsh sites and the three forested sites.

27 Wells are vented and secured to marsh surface. Salinity, conductivity and water depth are recorded every fifteen minutes.

28 Data is uploaded from data sondes on a monthly basis, and then imported into Ecowatch software to facilitate statistical analysis.

29 Task 4. Salinity Spatial Synoptic OBJECTIVE: To spatially describe salinity across the entire marsh surface. Sampling has been conducted by airboat in June and October Sixty-two sites in the Savannah River marsh interior were visited in June An additional twenty sites were sampled in October Additional sampling is scheduled d for October 2001.

30 Task 5. Tidal Swamp Study (Gap Analysis) OBJECTIVE: To determine if tidal forest hydrology and species composition have been affected by development of the Savannah Harbor. A study has been initiated which focuses on the plant species found in tidal forests and the different hydrological conditions occurring there through time. Four sites have been established and are currently being sampled.

31 Sites are identified by aerial photography and groundtruthing. Belt transects are used to sample vegetation composition, sedimentation and interstitial salinity. Vegetation communities will be compared between sites and time

32 Task 6. Sediment Characterization/Mapping OBJECTIVE: To examine how sediments aid in determining vegetation composition of the marshes of the lower Savannah River delta. Conducted in October 2000 in conjunction with synoptic salinity sampling and groundtruthing.

33 Substrate samples are being analyzed for bulk density and percent organic. Sieved samples are awaiting anion chemistry analysis by the University of Florida Analytical Soil Lab.

34 Task 7. Vegetation Change Analysis OBJECTIVE: To attempt to use satellite imagery to detect vegetation change. Classification of satellite imagery will utilize a combination of data from visual surveys and Task 1 vegetation associations. Images from 1986/87 and 2000/01 will be compared to detect changes in vegetation composition and distribution.

35 Task 8. Marsh Succession Model Development Support ENVI IRONMENTA AL SUITE SALINITY i SOIL TYPE i FLOODING i DISTANCE FROM HABITAT i EXISTING VEGETATION i etc SALINITY SOILS HYDROLOGY PROXIMITY VEGETATION GEOGRAPHIC INFORMATION SYSTEM MULTIVARIATE STATISTICAL ANALYSIS NEXT i FOR I=1, N PREDICTED HABITAT WHERE DOES PREDICTED HABITAT OCCUR?

36 Task 9. Migratory Bird Study OBJECTIVE: To determine the migratory bird species utilizing different areas of the Savannah marshes. A comparative study of bird species utilization of different tidal areas is being conducted during Spring and Fall migrations.

37 Banding was conducted for 7 weeks during Fall 2000 migration and for 8 weeks during Spring 2001 migration. Mist nets were set up at five sites: 3 of the Back River marsh sites, 1 Back River forested site and 1 at the Wright River.

38 Each bird caught was identified to species, sexed, measured and banded with USFWS aluminum bands.

39 During Fall Migration 2000 a total of 643 birds were banded, with 29 species represented. During Spring Migration 2001 a total of 260 birds were banded, with 24 species represented. Two species were common to all sites: swamp sparrow and common yellow-throat. Species unique to the fresh marsh (B1M) include: house wren, Swainson s thrush, ruby-throated hummingbird and ruby-crowned kinglet. Correspondence analysis will be conducted to examine relationships between bird species and habitat type.

40 Task 10. Fish and Other Nekton Species Utilization OBJECTIVE: To determine the community composition of nekton utilizing the tidal wetlands. A comparative methods approach is being employed at the four Back River Marsh Sites. Four 6 m 2 bottomless lift nets per site (total 16). Two modified flume trap nets per site (total 8).

41 Bottomless lift nets otto ess t ets sample the inner, higher marsh and provide density estimates.

42 Flume-trap nets serve as qualitative assessment of species as they enter and exit the lower marsh areas closer to canals.

43 N kt l t d b l ti Nekton samples are sorted by location and species, counted, weighed, and measured.

44 A high diversity of life stages has been found to date. Most abundant species Fundulus F d l heteroclitus (mummichog) Less abundant species include: Gobionellus boleseoma (darter goby) Leiostomus xanthrus (spot) Bairdiella chrysoura (silver perch) Anquilla rostrata (american eel) Myrophis punctatus (speckled worm eel)

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