low-cost transplanting technique for shoalgrass (Halodule wrightii) and manatee grass (Syringodium filiforme)

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|XENVIRONMENTAL IMPACT RESEARCH PROGRAM

INSTRUCTION REPORT EL-84-1

._ ALOW-COST. ::TRANSPLANTING TECHNIQUE FOR
SHOALGRASS (HALODULE WRIGHTI) AND
MANATEE GRASS (SYRINGODIUM FILIFORME)

by
M. S. Fonseca
Department of Environmental Sciences
University of Virginia
Charlottesville, Virginia 22903

W. J. Kenworthy, K. M. Cheap, C. A. Currin, G. W. Thayer
X, ~~~~~~Beaufort Laboratory, Southeast Fisheries Center
~/~-~ ~~~~~~National Marine Fisheries Service
Beaufort, North Carolina 28516

D~tT'~ �COMMERCE NOA~
SlAs / -I 'r ,"NTER
S~ui N AVENUE
.~ ~~~i .~ "F AA ,ae )O5-2413

- l~c-: of typ Li bzrarY September 1984
Final Report
Approved For Public Release; Distribution Unlimited

Prepared for DEPARTMENT OF THE ARMY
TA * US Army Corps of Engineers
7 * Washington, DC 20314-1000
.W34 Under Environmental Impact Research Program
no. Work Unit 31632
EL-84-1 Monitored by Environmental Laboratory
US Army Engineer Waterways Experiment Station
aIN PO Box 631, Vicksburg, Mississippi 39180-0631

Destroy this report when no longer needed. Do not return
it to the originator.

The findings in this report are not to be construed as an official
Department of the Army position unless so designated
by other authorized documents.

The contents of this report are not to be used for
advertising, publication, or promotional purposes.
Citation of trade names does not constitute an
official endorsement or approval of the use of
such commercial products.

PREFACE

This report was sponsored by the Office, Chief of Engineers (OCE),

U. S. Army, as a part of the Environmental Impact Research Program (EIRP)

Work Unit 31632 entitled Coastal Erosion Control Techniques Using Plants,

which was assigned to the U. S. Army Coastal Engineering Research Center

(CERC). The Center, originally located at Fort Belvoir, Va., moved to the

U. S. Army Engineer Waterways Experiment Station (WES), Vicksburg, Miss,,

on I. July 1983. The Technical Monitors for the study were Dr. John Bushman

and Mr. Earl Eiker of COE and Mr. David B. Mathis, Water Resources Support

Center.

The study and preparation of a draft final report were

accomplished during the time period October 1, 1982 to October 1, 1983;

preparation of the reproducible copy was done during February, 1984.

The report was prepared by Mr. Mark S. Fonseca, Department of

Environmental Sciences, University of Virginia, and Mr. W. Judson

Kenworthy, Ms. Kathleen M. Cheap, Ms. Carolyn A. Currin, and Dr. Gordon W.

Thayer of the Beaufort Laboratory, Southeast Fisheries Center, National

Marine Fisheries Service.

The authors express appreciation to D. Robertson, M. Robertson,

and C. Foltz for assistance in the field exercises, and to H. Gordy for

graphics.

Mr. Paul L. Knutson was technical monitor for this report, under

the general supervision of Mr. E. J. Pullen, Chief. ICoastal Ecology Branch,

and Mr. R. P. Savage, Chief, Research Division. Dr. Roger T. Saucier, WES,

was the Program Manager of EIRP.

Technical Director of CERC at Fort Belvoir during the study and

preparation of the draft final report was Dr. Robert W. Whalin. Commander

and Director of WES during preparation of the reproducible copy was COL

Tilford C. Creel, CE; Technical Director was Mr. F. R. Brown.

This report should be cited as follows:

Fonseca, M. S., Kenworthy, W. J., Cheap, K. M., Currin, C. A.,
and Thayer, G. W. 1984. "A Low-Cost Transplanting Technique
for Shoalgrass (Hatodue &Lghtii) and Manatee Grass (SyAingodium
fitiioume)," Instruction Report EL-84-1, US Army Engineer
Waterways Experiment Station, Vicksburg, Miss., prepared by
National Marine Fisheries Service under contract to
Environmental Laboratory.

CONTENTS

Page

CONJVERSION FACTORS, U. S. CUSTOMARY TO M~ETRIC (SI)... ........4
UNITS OF MWEASUREMWENT

HARVESTING AND STORING PLANTS. . ... .. . .. .. .. .. ....... . . ... ... . ..... 5

Identif'ying Preferred Harvest Sites.. ............. .5

Harvest Technique. ... .. . .. ... .. .. . . ... . .. .... .. ........... 7

PREPARING PLANTING UNITS. .. .. . . .... .. .. . .. .. .* .. . .. .. . .......... 8

PLANTING M~ETHOD .. . ... . ... .. .. . ... .. ... .... . ............. 9

PLANT MATERIAL REQUIREMVENTS. ... .. . .. .. ... .. . .. .. 0 . . .. .. . . .. . . ... .. 11

LABOR REQ~UIREMENTS.4. . .. .. ................. .. . ...... .13

Harvesting and Preparation of Planting Units ............13

Anchor Attachment . . . .. . .. .. 6.. .. . .. 0 ... . ............. 13

Planting . ............... .............. 13

Total Man-Hours ......... . .. ... ..........................15

REFERENCES ..... ...... ... ... ................. . .... . .... ~*16

CONVERSION FACTORS, U. S. CUSTOMARY TO METRIC (SI)
UNITS OF MEASUREMENT

U. S. customary units of measurement used in this report can be
converted to metric (SI) units as follows:

Multiply By To Obtain

acres 4046.873 square metres
feet 0.3048 metres
feet per second 0.3048 metres per second
inches 25.4 millimetres
square feet 0.09290304 square metres

A LOW-COST TRANSPLANTING TECHNIQUE FOR

SHOALGRASS (HaZodue tightii) AND

MANATEE GRASS (StrinQodium AtiAovnx)

Introduction

1. A cooperative research program between the Beaufort Laboratory

of the Southeast Fisheries Center, National Marine Fisheries Service, and

the U. S. Army Coastal Engineering Research Center (CERC) has developed

low-cost transplanting techniques for the subtropical seagrass species

shoalgrass (Haeodu.te wtghtZ) and manatee grass (Sytingodium gliforme).

Research is continuing into establishment of turtlegrass (Thaesiaa

ttudinum), which does not readily develop adequate bottom cover using

transplants of mature vegetative parts, as described here for shoalgrass

and manatee grass.

2. The transplanting techniques presented are effective for

restoring areas damaged by coastal engineering activities and update a

previous report by Phillips (1980). A similar technique was developed for

temperate species (Fonseca, Kenworthy, and Thayer 1982) and should be used

in concert with upcoming technical reports that describe environmental

requirements for some seagrass species and sediment stabilization

properties of others.

Harvesting and Storing Plants

Identifying preferred harvest sites

3. Seagrass transplants should be obtained from healthy,

well-established meadows large enough to minimize the impact of plant

removal. When no reasonable alternative to loss of seagrass habitat

exists, areas to be destroyed should also be considered as possible

harvest sites for onsite compensation of that loss. Research has

demonstrated that eelgrass (Zoztejz mauna) transplants collected from high-

current areas are found at higher densities than at low-current areas and

sometimes exhibit higher growth rates than transplants from low-current areas

(Fonseca et al. 1979). These attributes can improve collection efficiency

and rates of seagrass bed development (Fonseca, Kenworthy, and Thayer 1981).

Our experience suggests that these characteristics may also be true for

shoalgrass and manatee grass collected from moderate- and high-current areas.

Moderate- to high-current areas are defined as those areas in which water

surface current velocity ranges between 0.8 and 1.6 ft/sec.*
4. Sufficient numbers of apical meristems, or growing tips, are

necessary for successful transplants. These are illustrated in Figure 1,

and collectors should be familiar with their appearance. Upon identifying

a potential harvest site, random subsamples of at least 10 planting units

(a group of shoots with anchoring device, see page 8) should be made

from transplant stock collected from several different locations in the

harvest site. The number of apical meristems per planting unit should be

recorded. It is recommended that there be a mean ratio of apical meristems

to planting units of 1.0, although successful plantings have been established

with a mean ratio as low as 0.4. Aerial runners, which always have apical

meristems, are sometimes available as an alternative to rhizomes which must

be dug up in transplanting these species (techniques are described in later

sections). "Aerial runners" is a misnomer for what are actually rhizomes

* A table of factors for converting U. S. customary units of measurement
to metric (SI) units is presented on page 4.

growing out of the sediment exhibiting a stoloniferous-like form. The

distribution of aerial runners is not known to be controlled by current

regime; therefore, current is not a harvesting site criterion when using this

method.

\/\1) jSyringodian thank Holo Sdule wrichtil

a. SyVingaodAum 6iei orme b. Halo dule wrightil

Figure 1. Aerial runners (A and B) and rhizomes (C and D)
with apical meristems. Section A illustrates the anchor's
placement on a planting unit. The dashed lines indi-
cate the point of detachment when harvesting
planting unit.

Harvest technique

5. Two techniques that may be employed in the harvest of shoalgrass

and manatee grass are (a) the collection of aerial runners and (b) the removal

of "sods" or mats of seagrass from the sediment.

6. Aerial runners containing at least 6 shoots and the apical

meristem are removed from the plant by hand. The dashed lines in Figure 1 (A

and B) illustrate the point at which aerial runners should be detached.

'7.' Harvesting sods is most readily accomplished with a dive knife

or shovel inserted 6-8 in. into the substrate. A sod of seagrass is cut

out and -carefuflly removed from the sediment to avoid damaging the plants

and to preserve the root-rhizome mat. Sod harvest necessitates some

disruption of the donor meadows. Sods should be cut in small, shovel-sized

sections from the meadow as widely dispersed as possible to facilitate

regrowth into the shovel hole. The harvested seagrass mat should be gently

rinsed free of sediment. Individual planting units from this material will

resemble the rhizomes in Figure 1 (C and D).

Storage guidelines

8. Aerial runners and mats of seagrass should be stored in ambient

seawater and processed into planting units within 36 hr. If possible, the

water in closed storage containers (plastic trashcans work well) should be

aerated; othc.Lwilc replace the water frequently. For outdoor storage the

planting material can he retained in coarse mesh bags (typical nylon dive

bags work well) and hung overboard from a boat or pier. For prolonged

storage of 2-3 weeks, floating pens with open tops (for light) are

suggested. Setting the mats of seagrass into shallow, flowing seawater

tables works well and provides an ideal area for sorting and preparing

planting units. These submerged plants do not tolerate any exposure to

direct sun when out of the water; they should always be kept in ambient

seawater.

Preparing Plantinq Units

9. A planting unit (PU) consists of a section of aerial runner that

has at least 6 shoots and the apical meristem. Properly harvested aerial

runners will need no sorting prior to transplanting. If the plant material

was harvested by the sod method, planting units consisting of at least 3

healthy rhizoimes bearing a minimum of 5 intact shoots will need to be sorted

from the mat.

10. Anchors must be used to secure the plant to the sediment.

Anchors can be made from pieces of sturdy wire approximately 8 in. in length

and bent into U-shaped pins. Bent sections of coat hangers or commercially

available erosion control fabric pins work well. Figure lA illustrates

placement of the anchors over the transplant stock.

11. Additional preparation may be necessary, depending upon the

current velocity at the transplant site. In moderate-to high-current

areas, planting units are attached to anchors by twist ties. The anchor

should be attached to a sturdy portion of the runner(s) or rhizome(s). in

low-current areas it is not necessary to attach planting units to anchors;

the appropriate number of anchors and transplant stock need only be brought

to the transplant site.

Planting Method

12. Proper handling and spacing of planting units is essential for

a successful transplant. Planting units should be kept covered with

seawater at all times and handled carefully to reduce breakage and

transplant shock.

13. Transplanting can be done in shallow water areas (up to about

2 ft deep) by wading workers or by SCUBA divers in deeper areas. Planting

grids with the proper spacing should be established using a weighted line

marked in the calculated spacing units or by other measuring devices.

14. Planting units need to be secured to the sediment surface but

not buried. The U-shaped anchors are placed over the rhizome or runner of

the planting unit and then pushed into the sediments until the planting

unit is held firmly against the bottom and will not be removed by current

or wave action (Figure 2), Greatest efficiency is obtained when personnel

work in teams, with one worker holding the planting unit in position while

the other worker places the anchor to secure it. When planting units are

already attached to anchors, one worker plants while another individual

provides a continuous supply of planting units.

Figure 2. Planting method described in text showing plant-
ing unit, anchor, and weighted line marked in spacing
units. Planting unit is inserted next to the
marked line

Plant Material Requirements

15. To determine the required rntmber of planting units and spacing

between them for a transplant area, first determine which species will be

used, the desired number of days for transplant stock to cover the area,

and the size of the transplant area in square feet. Based on the species

used and the desired number of days to coverage, determine the Y value

from the table below. For example, if shoalarass Is to be used and the value

for days tn coverage is 125, then Y - 7-5/rg6

Days to Y_ Valu.e (ft2)
Coverage
Shoalgrass (H-l . Manatee grass (S.f.)

50 0.7543 0.2765
75 1.6248 0.4250
100 3.5002 0.6521
125 7.5406 0.9996
150 16.2444 1.5333
175 34.9969 2.3381
200 75.3975 3.5852

16. rhp Y values given above were dprivpd from the formula:

y _ srt (1)

a Time 0 nrea (ft?)
(H.w. = 0.1625; SI, - 0,!173)

e = base of the system of ,satiral logarithms

- (l+t)l/t as t goes to 0 = 2.7182818

r = Instantaneous growth coefficient
(H.w. - 0.0307, Stf. = 001'71)

t = Days to coverge.

17. To calculate the number of planting units needed for a

transplant site use the following formula:

Number of PUs = Area of transplant in square feet
y C~~~~~~~~~2)
Y

To calculate the spacing between PUs in the planting grid, use the

following formula:

Distance between PUs in feet =Area of transplant in square feet
Number of PUs (3)

18. As another example, assume a transplant area of 3 acres is to

be planted with manatee grass. The transplants should cover the area in 150

days. Convert acres to square feet as follows:

3 acres x 43,500 ft2/acre = 130,500 ft2

The Y value for manatee grass at 150 days is 1.5333; hence:

Number of PUs = 1305500 = 85,111
1.5333

Distance between PUS = 130-950 = 1.24 ft

19. The authors would like to point out that of the two species,

shoalgrass had a higher growth rate when transplanted. If stock availability

and site environmental conditions do not suggest a particular species, the

choice of a faster-growing species will reduce total man-hours required for

the transplant. Planting both species together would, however, allow for a

natural selection of the best species for the site. The selection of a

longer time period to coverage will also result in fewer total man-hours

required.

20. Figure 3 and 4 illustrate the development of a shoalgrass

planting unit from transplant to 160 days' growth.

Labor Requirements

21. Labor rates for the three phases of planting are discussed

below.

22. Harvesting and preparation of planting units.

a. Aerial runners.

(1) Shoalgrass - 500 aerial runners or planting units

per man-hour.

(2) Manatee grass - 325 aerial runners or planting units

per man-hour.

b. Sods.

For either species, 18,000 shoots or 3,000 planting units

per man-hour.

23. Anchor Attachment. If planting units are to be attached to

anchors, labor rate is 100 PUs per man-hour.

24. Planting.

a. Planting rate for wading, non-SCUBA assisted workers is

about 150 PUs per man-hour in most habitats.

b. Planting rate for SCUBA-assisted workers is about 175 PUs

per man-hour. (Note: although SCUBA-assisted workers are

at least 15 percent faster than non-SCUBA assisted

workers, wage difference has always resulted in non-SCUBA

workers being most economical when conditions permit.)

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Figr,- ~.Newly planted shoalgrass stock
p- �

Figure 4. Shcal,!rs taslant after 160 days of growth
14 $
r ~ ~ ~ ~ i. * ~~~~~~~52~~~4"

Fiy~~~i;-.-~ 4� t. N -�w24 224%te ,4agas t

:9:~~~~~~22'

F;:r ~ ~ ~ r24

: I :: .::~~24t2242S~

14~~~~~~24

25. Total Man-Hours. As an example, determine total man-hours

required to harvest, prepare, and plant 25,000 PUs of shoalgrass from sod

samples. Planting units were attached to anchors and wading workers were

used.

Man-hours
Harvest (25,000 PUs + 3,000 PUs/man-hour) 8.3
Attaching anchors (25,000 PUs + 100 PUs/man-hour) 250.0
Plantinq (25,000 PUs + 150 PUs/man-hour) 166.7
TOTAL 425.0

26. This estimate includes only onsite work; it does not include

travel, gear preparation, or additional requirements for safety of workers

and equipment.

Summary

27. The planting techniques recommended in this report make use of

mature vegetative plant material that can be acquired with (sod) or without

(aerial runners) impact to the donor site. Based on the estimated man-hour

requirements for each collection technique reported herein, a cost-benefit

analysis with regard for the impact to the donor site could be completed.

28. Cost estimates must account for the attachment of anchors in

moderate- to high-current areas, as well as consideration of shallow water

versus SCUBA-assisted planting.

29. Material requirements are estimated by accounting for the

species selected, the species growth rate, and the area to be covered.

Formulas are provided for simplified computation of spacing of planting

units to achieve coverage within the desired time period.

30. The table for computation of Y values was developed from the

results of several experimental pilot plantings in which the transplants

were carefully monitored for 160 days and the growth rates and area covered

were recorded.

References

Fonseca, M. S., Kenworthy, W. J., and Thayer G. W. 1981. "Transplanting of
the Seagrasses Zostera marina and Halodule wrightii for the Stabili-
zation of Subtidal Dredged Material", Annual Report, Beaufort Labora-
tory, Beaufort, N. C.

Fonseca, M. S., Kenworthy, W. J., and Thayer, G. W. 1982. "A Low-Cost
Planting Technique for Eelgrass (Zostera marina L.)," Coastal En-
gineering Technical Aid 82-6, U. S. Army Corps of Engineers, Coastal
Engineering Research Center, Ft. Belvoir, Va.

Fonseca, M. S., Kenworthy, W. 3., Homziak, J., and Thayer, G. W. 1979.
"Transplanting of Eelgrass and Shoalgrass as a Potential Means of
Mitigating A Recent Loss of Habitat", Proceedings of the Sixth
Annual Conference on Wetlands Restoration and Creation, D. P. Cole, ed.

Phillips, R. C. 1980. "Planting Guidelines for Seagrasses," Coastal
Engineering Technical Aid 80-2, U. S. Army Corps of Engineers, Coastal
Engineering Research Center, Ft. Belvoir, Va.

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REPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM
1. REPORT NUMBER 2. GOVT ACCESSION NO. 3. RECIPIENT'S CATALOG NUMBER

Instruction Report EL-84-1
4. TITLE (and S.ubtlre) 5. TYPE OF REPORT & PERIOD COVERED
A LOW-COST TRANSPLANTING TECHNIQUE FOR SHOALGRASS Final report
(HALODULE WRIGHTII) AND MANATEE GRASS (SYRINGODIUM Fina repor
FILIFORAIE) 6. PERFORMING ORG. REPORT NUMBER

7. AUTHOR(s) 8. CONTRACT OR GRANT NUMBER(a)
M. S. Fonseca, W. J. Kenworthy, K. M. Cheap,
C. A. Currin, and G. W. Thayer

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASK
University of Virginia, Department of Environmental AREA& iWORK UNIT NUMBERS
Sciences, Charlottesville, Va. 22903; National Environmental Impact Re-
Marine Fisheries Service, Southeast Fisheries search Program, Work Unit
Center, Beaufort Laboratory, Beaufort, N. C. 28516 31632
12. REPORT DATE
II. CONTROLLING OFFICE NAME AND ADDRESS September 1984
DEPARTMENT OF THE ARMY 13- NUMBER OF PAGES
US Army Corps of Enqineers 16
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Available fromn National Technical Information Service, 5285 Port Royal Road,
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19. KEY WORDS (Corirlnue an revee side if necoa.ery and Identlf) bIy block number)
Cost evaluation Sediment stabilization
Currents Shoalgrass
Manatee grass Transplanting techniques
Seagrass

20. ATS1:AC' fCoftriem - r.regr. Offf Ir ncer aId Iderily by block nurber)
A simplified, low-cost Transpianting technique has been developed for
seagrasses, Halo.dulZe rio.ht-i and Syringodium filiforme, for use in high- and
low-current recimes. The method makes use of mature, vegetative shoots, free
of sedin!nt and anchored to the substrate. The technique accounts for selection
of planting stock, species growth rate, and depth of planting site for estimat-
ing thu desi,!n, labor, and material requirements of a transplant. Examples are
provided to illustrate use of the tables and formulas for computing the neces-
sary requirements.
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