OCS Study 

•

MMS 2003-034 

An experimental evaluation of 

methods of surfgrass (Phyllospadix 

torreyi) restoration using early life 

history stages 

Final Technical Summary 

Final Study Report 

U.S. Department of the Interior 

Minerals Management Service

Pacific OCS Region 
OCS Study 

•

MMS 2003-034 
An experimental evaluation of 

methods of surfgrass (Phyllospadix 

torreyi) restoration using early life 

history stages 

Final Technical Summary 

Final Study Report 

Authors 

Daniel C. Reed 

Sally J. Holbrook 

Principal Investigators 

Prepared under MMS Cooperative 

Agreement No. 14-35-0001-30758 

by 

Coastal Marine Institute 

Marine Science Institute 

University of California 

Santa Barbara, CA 93106 

U.S. Department of the Interior 

Minerals Management Service Camarillo

Pacific OCS Region May 2003
OCS Study 

•

MMS 2003-034 

Disclaimer 

This report has been reviewed by the Pacific Outer Continental Shelf Region, Minerals Management 

Service, U.S. Department of the Interior and approved for publication. The opinions, findings, 

conclusions, or recommendations in this report are those of the author, and do not necessarily reflect the 

views and policies of the Minerals Management Service. Mention of trade names or commercial products 

does not constitute an endorsement or recommendation for use. This report has not been edited for 

conformity with Minerals Management Service editorial standards. 

Availability of Report

Extra copies of the report may be obtained from: 

U.S. Dept. of the Interior 

Minerals Management Service 

Pacific OCS Region 

770 Paseo Camarillo 

Camarillo, CA 93010 

Phone: 805-389-7621 

A PDF file of this report is available at: 

http://www.coastalresearchcenter.ucsb.edu/CMI/ 

Suggested Citation 

The suggested citation for this report is: 

Reed, D. C. and S. J. Holbrook. An experimental evaluation of methods of surfgrass (Phyllospadix 

torreyi) restoration using early life history stages. MMS OCS Study 2003-034. Coastal Research Center, 

Marine Science Institute, University of California, Santa Barbara, California. MMS Cooperative 

Agreement Number 14-35-0001-30758. 96 pages. 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

5

Table of Contents 

FINAL TECHNICAL SUMMARY 1 

FINAL STUDY REPORT 11 

 

Methods for Enhancing Habitat Value of Artificial Structures 

by Establishing Surfgrass (Phyllospadix torreyi). 

by S. J. Holbrook, D. C. Reed and J. S. Bull 11 

 Spatial and temporal patterns of predation on seeds of 

surfgrass, Phyllospadix torreyi.

by S. J. Holbrook, D. C. Reed, K. Hansen and C. A. Blanchette 19 

Survival experiments with outplanted seedlings of surfgrass 

(Phyllospadix torreyi) to enhance establishment on 

artificial structures 

by S. J. Holbrook, D. C. Reed and J. S. Bull 27 

An experimental evaluation of different methods of restoring 

Phyllospadix torreyi (Surfgrass). 

 by J. S. Bull, D. C.Reed, and S. J. Holbrook 33 

An experimental evaluation of different methods of restoring 

Phyllospadix torreyi (Surfgrass). 

 M.A. Thesis by J. S. Bull 55 

 

 Abstract 56 

Chapter 1: An experimental evaluation of different 

methods of restoring Phyllospadix torreyi (Surfgrass) 57 

 

Introduction 57 

 Methods 58 

 Results 63 

 Discussion 69 

 Conclusion 72 

 References 73 

 

Appendix I: Growth and survivorship of naturally 

recruited surfgrass (Phyllospadix torreyi) seedlings at 

rocky intertidal reef 77 

Appendix II: Growth and survivorship of surfgrass 

(Phyllospadix torreyi) seedlings outplanted on 

epoxy beads 85 
Final Technical Summary – Reed and Holbrook 

 6

Appendix III: Growth comparison of transplanted and 

undisturbed surfgrass (Phyllospadix torreyi) 

rhizome sprigs 89 

Appendix IV: Survivorship of surfgrass 

(Phyllospadix torreyi) seedling laboratory controls 92 

Appendix V: The availability of surfgrass 

(Phyllospadix torreyi) sprigs for transplanting at an 

intertidal and subtidal rocky reef 94 

Appendix VI: Leaf and rhizome biomass of surfgrass 

(Phyllospadix torreyi) rhizome sprigs used in 

restoration experiments 95 

Acknowledgements 96 

 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

1

FINAL TECHNICAL SUMMARY 

STUDY TITLE: An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) 

restoration using early life history stages 

REPORT TITLE: An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) 

restoration using early life history stages 

CONTRACT NUMBER(S): 14-35-0001-30758, Task # 15118 

SPONSORING REGION: Pacific 

APPLICABLE PLANNING AREAS: Southern California 

FISCAL YEAR(S) OF PROJECT FUNDING: FY 98, FY 99, FY 00 

COMPLETION DATE OF REPORT: March 2003 

COST(S): FY 98 - $62,354; FY 99 - $66,172; FY 00 - $40,357; FY 01- no cost; FY 02 – no cost 

CUMULATIVE PROJECT COST: $168, 883 

PROJECT MANAGER(S): Russell J. Schmitt 

AFFILIATION: University of California, Santa Barbara 

ADDRESS: Coastal Research Center, Marine Science Institute, University of California, 

Santa Barbara, CA 93106-6150 

PRINCIPAL INVESTIGATORS: 1

Daniel C. Reed and 2Sally J. Holbrook 

ADDRESSES: 1Marine Science Institute, University of California, Santa Barbara, CA 93106-

6150; 2Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 

93106-9610 

KEY WORDS: artificial structures, cost-effectiveness, Phyllospadix torreyi, plugs, predation, 

restoration, rhizome growth, seagrass, seeds, seedlings, sprigs, surfgrass, survivorship, transplant 

BACKGROUND: Increased urbanization of coastal areas has led to the degradation of many 

seagrass populations due to increases in nutrient loading, polluted waste from sewage and 

industrial discharges, coastal development and offshore construction, and recreational and 

commercial boating and fishing. The high ecological importance of seagrasses, coupled with 

their susceptibility to damage from a range of human activities and natural disturbances, have 

sparked much interest in understanding their ecology and developing methods for restoring 

damaged populations.
Final Technical Summary – Reed and Holbrook 

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Previous attempts to restore seagrass populations often have relied on transplanting older life 

stages. In many cases, transplanting techniques have been successful in promoting the 

establishment of new plants. Although the cost-effectiveness of different planting techniques has 

been examined in some cases, there have been few attempts to measure whether damage to donor 

populations from which transplants are collected causes long-term losses to otherwise healthy 

populations. The potential for such damage has prompted studies to explore the use of seeds and 

cultivated seedlings in seagrass restoration, but relatively little research on this has been done to 

date. 

In the United States, seagrass restoration efforts have focused on species that occupy shallow, 

soft-bottom habitats such as Halodule wrightii and Zostera marina. Surfgrasses such as 

Phyllospadix torreyi pose special challenges for restoration because the transplanting techniques 

that have been developed for other seagrasses are not applicable. Unlike most seagrasses, 

surfgrasses grow on exposed rocky coasts. Adventitious roots from the rhizome secure the plant 

to hard substrata. Thus, successful transplantation depends not only on growth following 

relocation, but also on secure attachment that enables transplants to avoid dislodgement by 

breaking waves. Populations of P. torreyi typically extend from the low intertidal into the 

subtidal, and because wave forces vary greatly along this depth gradient, different restoration 

methods might be required at different depths. 

Results from our previous MMS-supported research have shown that P. torreyi produces copious 

amounts of seeds, whose germination is easily controlled in laboratory culture. This feature 

allows it to be propagated from laboratory-raised seedlings, as well as from sprigs or plugs taken 

from natural populations. Such flexibility could be of significant value in restoration if the 

relative performance of the different life forms varied along the depth gradient. The inability to 

restore populations of surfgrass motivated us to develop restoration techniques for this species. 

OBJECTIVES: Our research addresses the important issue of mitigation of adverse effects of 

OCS (Outer Continental Shelf) oil and gas related activities on surfgrass (Phyllospadix spp.) 

communities. Phyllospadix is an important structure-forming plant in the intertidal and shallow 

subtidal zones that is impacted by a number of activities associated with offshore oil and gas 

production. With funding from Santa Barbara County and the MMS - UC Coastal Marine 

Institute Program, we have gathered much needed information on the reproductive ecology of 

Phyllospadix and we identified the most appropriate life stages of surfgrass for use in restoration. 

The primary objectives of this project were to: (1) test the feasibility of various techniques of 

transplanting laboratory reared seedlings to the field and evaluate their usefulness in restoring 

damaged surfgrass populations, (2) collect information on the growth and survivorship of 

naturally recruited surfgrass seedlings for use in estimating the time required for restored 

populations to fully recover, (3) compare the efficacy of using seedlings, sprigs (short lengths of 

rhizome containing a few shoots), and plugs (a cohesive clump of shoots and rhizomes) for 

potential restoration in the intertidal and subtidal, and (4) determine rates and sources of 

predation on surfgrass seeds. 

DESCRIPTION: 

Techniques for transplanting laboratory-reared seedlings 

Three experiments were conducted to test different outplanting techniques, each lasting 

approximately three months. The first experiment tested the role of host type on seedling 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

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survival, as well as the effects of abrasion from nearby plants. Three types of hosts were tested: 

two species of red algae (Bossiella orbigniana (Dec) Silva and Corallina officinalis var. 

chilensis Dec), and an artificial host consisting of a 20x20cm piece of 1 mm diameter nylon mesh 

(a fabric diameter similar to that of the algae). Six 30x30cm plots were established in 

monospecific patches of Bossiella and Corallina, respectively in the winter of 1998. To test for 

effects of abrasion on seedling survivorship, the branches of all algae in half of the plots were 

clipped to within 1cm of the holdfast. The remaining plots were unaltered (‘unclipped’). 

SCUBA divers hooked the bristled arms of seedlings onto branches of clipped and unclipped 

holdfasts of Bossiella and Corallina using fine forceps in a manner resembling natural 

attachment of seeds (40 seedlings per plot, 3 treatment replicates). Artificial hosts were placed 

near unclipped plots of Bossiella and Corallina (3 replicates for each species). Divers attached 

seedlings to the nylon mesh (10 seedlings per replicate), and then used underwater epoxy to 

fasten the artificial host to the substrate. 

In the second and third experiment, only artificial hosts were used. Seedlings were attached in 

the laboratory and the seeded hosts were then outplanted to the field during the winter of 1999. 

This method was explored because attaching individual seedlings to natural hosts in the field had 

proved difficult and time consuming. Two types of artificial hosts were tested: braided nylon 

string and braided nylon netting. In both cases, an opening was made in the braid by untwisting 

it one half turn. One of the arms of the germinated seed was inserted into the opening and 

hooked onto one of the braids. The opening closed upon relaxation, locking the seedling into 

place. Using this technique, many seedlings could be securely and rapidly fastened to the strings 

and nets. Seeded strings and nets were kept in seawater tables before transportation to the study 

site in coolers. 

The second experiment used nylon strings as hosts to explore effects of seedling density and 

abrasion from nearby plants. Strings were stretched across 0.5m square racks made of PVC 

tubing that were bolted to the ocean bottom using marine epoxy. In high-density and low-density 

treatments, 10 and 4 equally spaced strings were fastened to a rack, respectively (8 seedlings per 

string in both treatments). Four racks of each density were placed in dense patches of both 

clipped and unclipped Corallina. 

The third experiment used nylon netting as an artificial host to test for effects of seedling density 

and clipped algae vs. bare rock. Seedlings were outplanted at three densities (5, 20 or 105 

seedlings per net of 20 cm by 20 cm) in clipped patches of Corallina and in areas scraped to bare 

rock (4 replicates for each treatment). The netting was glued to the bottom. 

To evaluate potential effects of handling on seedling survivorship, we compared the survivorship 

of seedlings that had and had not been attached to artificial hosts. At the time of the second and 

third experiment (winter 1999), control groups of 20 seedlings each were handled in the same 

ways as outplanted seedlings and then returned to laboratory culture. Six groups consisted of 

seedlings that were attached to strings and six groups consisted of loose seedlings. Each group of 

20 seedlings was placed in a separate culture dish. These were maintained in the laboratory and 

survivorship was measured over 69 days. 
Final Technical Summary – Reed and Holbrook 

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Growth and survivorship of naturally recruited seedlings 

We measured natural mortality of seedlings to provide a baseline for comparison to outplanting 

experiments. Mortality of 335 naturally-recruited seedlings was estimated at a site located 20 km 

north of Santa Barbara, CA USA (34o 25' N 119o 57'W). Cohorts of seedlings were followed in 

nine fixed 0.64 m2 circular plots (9–241 seedlings present at the first count) for three months. 

Plots were selected in reef areas covered with P. torreyi and a variety of red algae including 

Corallina vancouverensis L. and Chondracanthus canaliculatus (Harv.), which have been 

proven suitable hosts. Each plot was carefully searched on three different occasions and all 

seedlings were counted. 

Efficacy of seedlings, sprigs and plugs for restoration 

Three potential restoration methods for P. torreyi to intertidal and shallow subtidal reefs near 

Santa Barbara, CA were compared: (1) seedlings cultivated in the laboratory and transplanted to 

the field, (2) sprigs (short lengths of rhizome containing a few shoots) collected from and 

transplanted to the study areas, and (3) plugs (cohesive clumps of rhizomes and shoots) collected 

from and transplanted to the study areas. 

 

Each method of restoration was evaluated using data collected on survivorship and growth of the 

transplants after six months, recovery of the donor population from which transplants were 

collected, and the amount of effort (i.e. time) involved in transplanting. Transplants were 

considered dead if they had no leaves or were no longer present on the reef. Growth of surviving 

transplants was estimated as the change in the aerial coverage of rhizome over the six-month 

experiment as determined by the linear dimensions of the basal area occupied by the rhizomes of 

each transplant. The percentage change in the number of leaves after six months ([(final number 

of leaves – initial number of leaves) / initial number of leaves] * 100) was used to assess the 

condition of surviving transplants. 

Seedlings attached to nylon line were transplanted to experimental plots 30 cm x 30 cm in area at 

the intertidal and subtidal study sites in November 2000 by fastening the ends of each nylon line 

directly to the reef using Z-Spar A788 marine epoxy putty. 

Sprigs were harvested at the intertidal and subtidal sites in November 2000, and each was 

immediately transplanted just outside (within 2 m) the surfgrass bed to a 15 cm x 15 cm plot that 

had been cleared of other biota. To harvest sprigs, an unbranched terminal end of an actively 

growing rhizome was carefully removed from the perimeter of a bed with a knife. The rhizome 

of each sprig was five cm in length and contained several lateral shoots and a terminal shoot. 

Sprigs were transplanted to the cleared areas by attaching the cut end of the rhizome to the reef 

using marine epoxy. The collection of sprigs resulted in a small loss in surfgrass from the donor 

bed. To measure recovery from this loss, a reference marker was glued to the reef next to the cut 

end of each donor rhizome (i.e., a rhizome from which a sprig was harvested). Recovery was 

estimated as the aerial coverage of new rhizome that grew from the cut end of the donor rhizome. 

The efficacy of using clumps of mature surfgrass was evaluated at the intertidal and subtidal sites 

beginning in August 1999. Square plugs of intertwined rhizomes and shoots were harvested 

from the middle of a bed of P. torreyi using a wide bladed putty knife and transplanted outside 

(within 2 m) of the surfgrass bed to plots that had been cleared of other biota. Clearings were 

made larger than the plugs in order to provide a 5 cm wide buffer from surrounding biota. Plugs 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

5

were attached by pulling the leaves through a square piece of 2.5 cm diameter stretch mesh nylon 

net that was cut to a size that was slightly larger than the square plug. The net was pulled tight 

over the plug and secured to the reef at the edges with marine epoxy. As done for sprigs, the 

leaves were trimmed to 20 cm in length to minimize drag. Three different sizes of plugs (small, 

5 cm x 5 cm; medium, 10 cm x 10 cm; and large, 20 cm x 20 cm) were transplanted to test 

whether plug size influenced: (1) survivorship and growth (i.e. increase in aerial coverage) of the 

transplanted plug, and (2) rate of recovery of the donor area from which the plug was collected. 

Six plugs of each size were transplanted to separate plots in each of the two sites. The collection 

of plugs resulted in the immediate loss of surfgrass in the donor beds equal to the aerial coverage 

of the plugs. To estimate the recovery of bare patches in the donor bed created by harvesting 

plugs, we marked each donor patch at the time of harvesting and made periodic measurements to 

assess the extent of in-growth from the edges of the bare patches by neighboring rhizomes. The 

recovery of donor patches was determined at the end of the six-month experiment by calculating 

the area of bare space remaining in each donor patch from linear measurements taken with a tape 

measure.

Rates and sources of predation on surfgrass seeds 

Temporal and spatial patterns of predation on seeds of Phyllospadix torreyi were quantified at 

four sites near Santa Barbara, CA. The intensity of predation on fruits prior to maturation and 

release from the spadix was assessed at each site at the peak of the flowering season (September) 

in 1997 and in 1998. Seed traps (consisting of two pieces of polyester mesh) were deployed in 

the surfgrass zone at the four sites from August 1995 until December 1998 to assess patterns of 

abundance of dehisced fruits (containing seeds) and intensity of predation. Traps were put out at 

the sites and retrieved a month later, at which time empty traps were re-deployed in the same 

positions. Upon return to the laboratory, traps were placed in seawater where they were held 

until seeds were counted (up to 48 hours). The entire trap was searched for fruits which were 

carefully removed and categorized as whole (intact with a viable seed present), germinated 

(intact seed with emergent shoot), eaten (seed visibly eaten out of fruit) or partial (only one arm 

present). 

 

SIGNIFICANT CONCLUSIONS: 

Techniques for transplanting laboratory-reared seedlings 

Our results suggest that transplanting laboratory –reared seedlings to the field may be a 

promising approach to enhancing populations of P. torreyi on artificial reefs. Artificial hosts 

may be used, with resulting short-term survival similar to that of naturally recruiting seedlings if 

appropriate techniques are selected. However, because of the inherently low survivorship of 

surfgrass seedlings, it may prove more difficult to enhance establishment of surfgrass populations 

using seedlings compared to other seagrass species. Longer and larger-scale test projects are 

required to assess whether rhizome attachment and growth rates of outplanted seedlings could 

match those of natural seedlings. 

Growth and survivorship of naturally recruited seedlings 

Seedlings of surfgrass naturally suffer high mortality from a variety of physical and biological 

causes. 
Final Technical Summary – Reed and Holbrook 

 6

Efficacy of seedlings, sprigs and plugs for restoration 

Results from our research suggest that efforts to restore damaged populations of P. torreyi are 

highly dependent on the type of enhancement technique used. The evaluation of several 

techniques revealed that transplanting sprigs was the most effective means of producing a net 

increase in area of surfgrass habitat per unit effort. This outcome was affected by several factors. 

While factors affecting favorable growth and survival were significant elements, costeffectiveness and recovery of donor plots also played important roles in determining the overall 

success of a technique. Depth also appeared to affect outcome, with subtidal transplants 

generally outperforming intertidal transplants for the same technique. The development of 

techniques that allow transplants to better withstand the harsh conditions of the intertidal should 

benefit restoration efforts in this zone. 

Rates and sources of predation on surfgrass seeds 

Surfgrass is a long-lived clonal plant that reproduces by vegetative spreading as well as periodic 

episodes of seedling recruitment. Clearly, the amount of predation loss of seeds of surfgrass is of 

a magnitude that potentially could contribute to the low numbers of seedlings typically observed 

in the populations we study. However, even when the amount of seed predation is so great that a 

majority of seeds that are produced by a population are consumed, there is no consensus 

regarding the potential for an impact on population dynamics or spatial distribution. Some 

terrestrial studies have revealed that seed predation can have substantial effects on local 

populations. Thus, for surfgrass, a high rate of seed predation could potentially influence 

population abundance if it occurred during times when conditions are favorable for seedling 

recruitment, and if density-dependent losses from other sources did not offset variation arising 

from differences in losses to predators. Clearly, resolving the importance of seed losses to 

population dynamics of surfgrass will require much additional information. This includes a 

fuller understanding of patterns of spatial and temporal variation in the intensity of seed 

predation as well as their underlying causes, so that the importance of seed predation relative to 

other processes that affect distribution and abundance can be assessed. 

STUDY RESULTS: 

Techniques for transplanting laboratory-reared seedlings 

Approximately half of the seedlings survived after seven days in clipped plots of both Bossiella 

and Corallina when seedlings were attached by hand onto the host algae. Nonetheless, only a 

small percentage survived to three months. In contrast, even short-term survival was close to 

zero in all unclipped plots and none survived 50 days. Careful searches of the host algae 

revealed that entire seedlings had disappeared, suggesting that the method of attaching seedlings 

to host algae with forceps resulted in high rates of dislodgement. Survival was higher in 

seedlings attached to nylon mesh, possibly because they were not as easily dislodged. Survival 

differed significantly among treatments, but none differed significantly from survival of the 

naturally recruited cohort. Post-hoc comparison of treatment means revealed that seedlings on 

nylon mesh outplanted to Corallina patches experienced significantly lower mortality than those 

outplanted to Bossiella patches or than seedlings attached to clipped algae. 

In the second experiment, percentage survival steadily declined over time in all treatments, with 

less than 10% remaining alive after four months. Seedlings were often abraded and broken, 

possibly caused by string movements during periods of high turbulence. Survival was similar 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

7

among all treatments and survival in each treatment was significantly lower than in the natural 

cohort. 

Survival was higher in the third experiment, when seedlings were attached to braided nylon 

netting. This method apparently minimized movements and prevented dislodgement. Survival in 

all treatments was similar to survival of naturally recruited seedlings. 

Growth and survivorship of naturally recruited seedlings 

Naturally recruited seedlings experienced substantial mortality. About half of the 335 seedlings 

died within three weeks of the initial survey, while 30% survived until the end of the three month 

study. 

Efficacy of seedlings, sprigs and plugs for restoration 

Transplanted seedlings survived poorly and had minimal rhizome growth at both the intertidal 

and subtidal sites, yet the individuals that did survive showed a 275 % increase in leaf number. 

Survivorship of transplanted plugs was high in both habitats; however, physical disturbances to 

the donor populations greatly exacerbated damage sustained at the time of collecting, yielding a 

substantial net loss in surfgrass. Sprigs transplanted to the subtidal had higher survivorship (71% 

vs. 48%) and a greater increase in the aerial coverage of rhizome (86% vs. 42%) than those 

transplanted to the intertidal. Of the three techniques, transplanted sprigs had the greatest overall 

increase in aerial coverage per unit effort, suggesting that this method may be the most effective 

approach for restoring P. torreyi. 

Rates and sources of predation on surfgrass seeds 

Over a period of four flowering seasons during 1995 - 1998, monthly patterns of seed fall and 

intensity of seed predation were similar among sites but were temporally quite variable. 

Abundance of dispersed seeds varied greatly both among seasons and years. Within a year, seeds 

were present in the environment every month but they peaked in abundance during the fall 

months following the annual flowering period. Seeds were more abundant during the earlier 

years of the study. The intensity of predation steadily increased throughout the study period, 

from a low of < 10 percent seeds consumed during 1995 to about 50 percent consumption by 

1997, and it was not correlated with abundance of seeds in the environment. Pre-dispersal seed 

loss also was estimated in two flowering seasons by counting the numbers of seeds consumed 

prior to release from the plant, and found to be relatively low (< 15 percent). No differences 

were detected among the four study sites in patterns of pre-dispersal loss. Field surveys were 

done at two sites to identify potential seed predators. Three of the most abundant species 

identified in these surveys were tested in the laboratory to determine size-specific patterns of 

feeding activity and to assess which early life stages of P. torreyi (fruits within spadices, 

dehisced fruits, and seedlings) were most vulnerable to predation. All three of the early life 

stages were consumed. The crabs Pugettia producta and Pachygrapsis crassipes were much 

more voracious predators than the isopod Idotea resecata.
Final Technical Summary – Reed and Holbrook 

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STUDY PRODUCTS: 

The following publications resulted from this work: 

Holbrook, S.J., D.C. Reed and J. S. Bull. 1999. Methods for Enhancing Habitat Value of 

Artificial Structures by Establishing Surfgrass (Phyllospadix torreyi). In Proceedings of the 

Seventh International Conference on Artificial Reefs and Aquatic Habitats, San Remo, Italy. 

Pp. 582-589. 

Holbrook, S.J., D.C. Reed, K. Hansen and C.A. Blanchette. 2000. Spatial and temporal patterns 

of predation on seeds of surfgrass, Phyllospadix torreyi. Marine Biology 136:739-747. 

Holbrook, S.J., D.C. Reed and J. S. Bull. 2002. Survival experiments with outplanted seedlings 

of surfgrass (Phyllospadix torreyi) to enhance establishment on artificial structures. ICES 

Journal of Marine Science 59:S350-S355. 

Bull, J.S. 2002. An experimental evaluation of different methods of restoring Phyllospadix 

torreyi (Surfgrass). M.A. Thesis. University of California Santa Barbara. 77 p. 

Bull, J.S., D.C.Reed, and S. J.Holbrook. 2003. An experimental evaluation of different methods 

of restoring Phyllospadix torreyi (Surfgrass). In review, Restoration Ecology.

The following presentations were made based on this work: 

Melissa Lee and Julia Diener, “Predation on surfgrass, Phyllospadix torreyii, spadices.” High 

School Mentorship Participant Presentation, 4th Annual Research Mentorship Symposium, 

UCSB, 1998. 

J. Scott Bull, “Marine Restoration.” Habitat Restoration Group, Museum of Systematics and 

Ecology, UCSB, 1998. 

J. Scott Bull, “Evaluation of Tests to Mitigate Losses of Surfgrass (Phyllospadix torreyi) from 

Anthropogenic Impacts.” Poster, University of California Toxic Substances Research and 

Teaching Program 12th Annual Research Symposium, Santa Barbara, CA. 1999. 

J. Scott Bull, “Development of Methods for Surfgrass (Phyllospadix torreyi) Restoration.” 

Summer Mentorship Program, UCSB, 1999. 

Ellen R. Feingold and Katie E. Gibbons, “The Spatial and Temporal Variability in Surfgrass, 

Phyllospadix torreyii, Reproductive Development in Santa Barbara County.” High School 

Mentorship Participant Presentation, 5th Annual Research Mentorship Symposium, UCSB, 

1999. 

S. Holbrook, D.C. Reed and J. S. Bull. “Methods for Enhancing Habitat Value of Artificial 

Structures by Establishing Surfgrass (Phyllospadix torreyi).” 7th International Conference on 

Artificial Reefs and Aquatic Habitats, San Remo, Italy, 1999. 

D. Reed and S. Holbrook. “Reproductive ecology of surfgrass in the context of restoration.” 

Invited symposium presentation, Western Society of Naturalists, Monterey, CA, 1999. 

Holbrook, S. and D. Reed. “Population ecology of surfgrass (Phyllospadix torreyi) and its 

potential application for restoration.” 5th International Temperate Reef Symposium, 

Capetown, South Africa, 2000. 

J. S. Bull. “Evaluation of Tests to Mitigate Losses of Surfgrass (Phyllospadix torreyi) from 

Anthropogenic Impacts.” Poster, 13th Annual UC Toxic Substances Research and Teaching 

Program Symposium, San Diego, CA, 2000. 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

9

J. S. Bull, “Evaluation of Tests to Mitigate Losses of Surfgrass (Phyllospadix torreyi) from 

Anthropogenic Impacts.” Poster, University of California Toxic Substances Research and 

Teaching Program 14th Annual Research Symposium, Lake Tahoe, CA, 2001. 

D. Reed, S.J. Holbrook, C. Blanchette and R.J. Schmitt. “Differential reproductive responses to 

environmental fluctuations in species with contrasting demographies.” Invited workshop 

talk, 6th International Temperate Reef Symposium, Christchurch, New Zealand, 2003. 
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An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 33

An Experimental Evaluation of Different Methods of Restoring Phyllospadix torreyi (Surfgrass) 

J. Scott Bull1, 4, Daniel C. Reed2, 3, Sally J. Holbrook1, 2

1

Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, 

CA 93106-6150, U.S.A. 

2

Marine Science Institute, University of California, Santa Barbara, CA 93106-6150, U.S.A. 

3

Corresponding author: reed@lifesci.ucsb.edu 

4

 Current Address: Shoreline Preservation Fund, University Center 2521, University of California, 

Santa Barbara, CA 93106-6150, U.S.A. 
Final Study Report – Reed and Holbrook 

 34

ABSTRACT 

The surfgrass Phyllospadix torreyi is an abundant seagrass found on rocky exposed shores of the 

Pacific coast of North America. In southern California, surfgrass populations are adversely affected by 

a range of natural events and anthropogenic activities. Few attempts have been made to develop 

restoration methods for surfgrass, and none have investigated the efficacy of using different life stages. 

We evaluated several techniques for restoration in intertidal and subtidal habitats using: 1) laboratoryreared seedlings transplanted to the field, 2) sprigs (short lengths of rhizome containing a few shoots) 

transplanted from undisturbed populations, and 3) plugs (a cohesive clump of shoots and rhizomes) 

transplanted from undisturbed populations. We calculated net change in the aerial coverage of 

surfgrass after six months, taking into account the recovery or additional losses from the donor 

population, and amount of effort involved in transplanting. Transplanted seedlings survived poorly 

and had minimal rhizome growth at both the intertidal and subtidal sites, yet the individuals that did 

survive showed a 275 % increase in leaf number. Survivorship of transplanted plugs was high in both 

habitats; however, physical disturbances to the donor populations exacerbated damage sustained at the 

time of collecting, yielding a substantial net loss in surfgrass. Sprigs transplanted to the subtidal had 

higher survivorship (71 % vs. 48 %) and a greater increase in the aerial coverage of rhizome (86 % vs. 

42 %) than those transplanted to the intertidal. Of the three techniques, transplanted sprigs had the 

greatest overall increase in aerial coverage per unit effort, suggesting that this method may be the most 

effective approach for restoring P. torreyi. 

Key Words: cost-effectiveness, Phyllospadix torreyi, plugs, restoration, rhizome growth, seagrass, 

seedlings, sprigs, surfgrass, survivorship, transplant 

INTRODUCTION 

Increased urbanization of coastal areas has led to the degradation of many seagrass populations due to 

increases in nutrient loading (Short & Burdick 1996; Short & Wyllie-Echeverria 1996), polluted waste 

from sewage and industrial discharges (Santour & Castel 1995; Morand & Briand 1996; Clark 1997; 

Schiewer 1998), coastal development and offshore construction (Cambridge & McComb 1984; 

McLusky et al. 1992; Sheridan et al. 1998), and recreational and commercial boating and fishing 

(Zieman 1976; Walker et al. 1989; Dawes et al. 1997). The high ecological importance of seagrasses 

(Harlin 1975; Stewart & Myers 1980; Fonseca et al. 1990), coupled with their susceptibility to damage 

from a range of human activities and natural disturbances, have sparked much interest in 

understanding their ecology (Duarte 1999) and developing methods for restoring damaged populations 

(Thorhaug 1986; Larkum et al. 1989; Edgar 1990; Williams & Davis 1996; Orth et al. 1999; Paling et 

al. 2001a, 2001b; Short et al. 2002). 

Previous attempts to restore seagrass populations often have relied on transplanting older life stages 

(Thorhaug 1986; Thom 1990; Davis & Short 1997; Orth et al. 1999; Paling et al. 2001a, b). In many 

cases, transplanting techniques have been successful in promoting the establishment of new plants 

(Fuss & Kelly 1969; Kelly et al. 1971; Phillips 1974; Fonseca et al. 1994; Balestri et al. 1998). 

Although the cost-effectiveness of different planting techniques has been examined in some cases (e.g., 

Thorhaug 1986), there have been few attempts to measure whether damage to donor populations from 

which transplants are collected causes long-term losses to otherwise healthy populations. The 

potential for such damage has prompted studies to explore the use of seeds and cultivated seedlings in 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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seagrass restoration (Balestri et al. 1998; Harwell & Orth 1999; Holbrook et al. 2002), but relatively 

little research on this has been done to date (Orth et al. 2000). 

In the United States, seagrass restoration efforts have focused on species that occupy shallow, softbottom habitats such as Halodule wrightii and Zostera marina (Thom 1990). Surfgrasses such as 

Phyllospadix torreyi pose special challenges for restoration because the transplanting techniques that 

have been developed for other seagrasses are not applicable. Unlike most seagrasses, surfgrasses grow 

on exposed rocky coasts. Adventitious roots from the rhizome secure the plant to hard substrata (den 

Hartog 1970; Phillips 1979; Cooper & McRoy 1988). Thus, successful transplantation depends not 

only on growth following relocation, but also on secure attachment that enables transplants to avoid 

dislodgement by breaking waves. Populations of P. torreyi typically extend from the low intertidal 

into the subtidal, and because wave forces vary greatly along this depth gradient, different restoration 

methods might be required at different depths. 

P. torreyi produces copious amounts of seeds, whose germination is easily controlled in laboratory 

culture (Williams 1995; Reed et al. 1998). This feature allows it to be propagated from laboratoryraised seedlings, as well as from sprigs or plugs taken from natural populations. Such flexibility could 

be of significant value in restoration if the relative performance of the different life forms varied along 

the depth gradient. The inability to restore populations of surfgrass motivated us to develop restoration 

techniques for this species. Here we investigated the efficacy of using seedlings, sprigs and plugs for 

restoration in the intertidal and subtidal. Specifically, we evaluated the three life forms with respect to: 

1) increase in aerial coverage and survivorship of transplants, (2) effort involved in collecting, 

preparing and transplanting, and (3) residual damage to donor populations. 

METHODS 

Three potential restoration methods for P. torreyi to intertidal and shallow subtidal reefs near Santa 

Barbara, CA were compared: (1) seedlings cultivated in the laboratory and transplanted to the field, (2) 

sprigs (short lengths of rhizome containing a few shoots) collected from and transplanted to the study 

areas, and (3) plugs (cohesive clumps of rhizomes and shoots) collected from and transplanted to the 

study areas. Intertidal studies were conducted during low tide at More Mesa Reef (340

25’N, 

119057’W), a broad, gently sloping reef fractionated by sand channels. Patches of the red algae 

Corallina vancouveriensis, Gelidium purpurascens, and Chondracanthus canaliculatus [which serve 

as attachment sites for surfgrass seeds (Blanchette et al. 1999)] were common in the study area. P. 

torreyi formed dense beds on most of the emergent reef in the low intertidal zone to the shallow 

subtidal zone at More Mesa Reef. Seedlings, sprigs and plugs were transplanted into cleared areas on 

the reef adjacent to P. torreyi. The sand channels at More Mesa broaden with depth, resulting in little 

rocky habitat for surfgrass in the subtidal zone. Consequently, subtidal studies were done using 

SCUBA at nearby Mohawk Reef (340

 24’ N, 119044’ W), where P. torreyi forms large, patchy beds on 

a broad, gently sloping reef interspersed with stands of coralline algae consisting primarily of Bossiella 

orbigiana and Corallina officinalis. Seedlings, sprigs and plugs were transplanted to depths of 2.5 to 4 

m below MLLW in plots cleared of coralline algae and other biota that were located next to established 

surfgrass beds. 

Transplant experiments were initiated in the late summer and fall, the time of year when most 

surfgrass seeds are released and germinate in southern California (Williams 1995, Holbrook & Reed 

unpublished data). Each method of restoration was evaluated using data collected on survivorship and 
Final Study Report – Reed and Holbrook 

 36

growth of the transplants after six months, recovery of the donor population from which transplants 

were collected, and the amount of effort (i.e. time) involved in transplanting. Transplants were 

considered dead if they had no leaves or were no longer present on the reef. Growth of surviving 

transplants was estimated as the change in the aerial coverage of rhizome over the six-month 

experiment as determined by the linear dimensions of the basal area occupied by the rhizomes of each 

transplant. The percentage change in the number of leaves after six months ([(final number of leaves – 

initial number of leaves) / initial number of leaves] * 100) was used to assess the condition of 

surviving transplants. We measured leaf number as opposed to the more traditional metric of shoot 

number because it was difficult to accurately count shoots in the wave swept surf zone where shifting 

sand frequently buried shoots above the sheath. However, the number of leaves per shoot at our sites 

was very consistent (mean 2.99 + 0.05 SE, N = 210 shoots), and thus it can be used to estimate the 

number of shoots. 

Seedlings 

Seedlings were germinated from seeds obtained from reproductive shoots of plants collected in 

September 2000 at the two study sites and other nearby intertidal and subtidal locations. Reproductive 

shoots were cut several centimeters above the rhizome, transported to the laboratory, and placed in a 

flow through seawater tank until fruits dehisced (about 1 month). Dehisced fruits were placed in 

culture as per the methods of Reed et al. (1998), and the single seed within the fruits germinated within 

one month of fruit dehiscence. At the time of transplanting (approximately one month postgermination) seedlings lacked rhizomes and consisted of a single leaf approximately two cm in length 

that was attached to the endocarp of the fruit. 

Each seedling was attached to a 7 cm long piece of braided nylon line (1 mm diameter) by inserting 

one of the arms of the fruit into an opening in the line made by untwisting the braids one-half turn 

(Figure 1a). Tiny bristles along the inside arm of the fruit hooked onto one of the braids, locking the 

seedling in place. Attached, seedlings were placed in plastic bags with seawater and transported to the 

field in insulated containers. 

Seedlings attached to nylon line were transplanted to experimental plots 30 cm x 30 cm in area at the 

intertidal and subtidal study sites in November 2000 by fastening the ends of each nylon line directly to 

the reef using Z-Spar A788 marine epoxy putty. Eighteen seedlings were transplanted in a uniform 

grid to each of 12 plots at each of the two sites and their survivorship was monitored periodically 

during the six month experiment. All experimental plots were located adjacent to healthy stands of 

surfgrass and were cleared of algae and sand prior to transplanting to facilitate attachment with epoxy. 

Branches of coralline algae growing adjacent to the plots were trimmed to reduce abrasion and 

dislodgement of the newly transplanted seedlings. 

Sprigs 

Sprigs were harvested at the intertidal and subtidal sites in November 2000, and each was immediately 

transplanted just outside (within 2 m) the surfgrass bed to a 15 cm x 15 cm plot that had been cleared 

of other biota. To harvest sprigs, an unbranched terminal end of an actively growing rhizome was 

carefully removed from the perimeter of a bed with a knife. The rhizome of each sprig was five cm in 

length and contained several lateral shoots and a terminal shoot. The mean number of leaves per sprig 

was 11.9 (± 0.9 SE) for subtidal transplants and 26.6 (± 1.5 SE) for intertidal transplants. Sprigs were 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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transplanted to the cleared areas by attaching the cut end of the rhizome to the reef using marine epoxy 

(Figure 1b). At least 1.5 cm of the actively growing terminal end of the rhizome of each sprig was 

exposed and not in contact with the epoxy. Leaves of transplanted sprigs were trimmed to 20 cm in 

length prior to attachment to minimize drag and reduce the chance of dislodgement while the epoxy 

hardened. Pilot studies determined that reducing drag by trimming leaves was a necessary condition 

for effective attachment of transplants. Forty-two sprigs were transplanted to an equal number of plots 

at each of the two sites. 

The collection of sprigs resulted in a small loss in surfgrass from the donor bed. To measure recovery 

from this loss, a reference marker was glued to the reef next to the cut end of each donor rhizome (i.e., 

a rhizome from which a sprig was harvested). Recovery was estimated as the aerial coverage of new 

rhizome that grew from the cut end of the donor rhizome. We were not able to relocate all of the 

donor rhizomes at the end of the study; six and nine donor rhizomes were used to calculate recovery 

from harvesting sprigs from the subtidal and intertidal sites, respectively. 

Plugs 

The efficacy of using clumps of mature surfgrass was evaluated at the intertidal and subtidal sites 

beginning in August 1999. Square plugs of intertwined rhizomes and shoots were harvested from the 

middle of a bed of P. torreyi using a wide bladed putty knife and transplanted outside (within 2 m) of 

the surfgrass bed to plots that had been cleared of other biota. Clearings were made larger than the 

plugs in order to provide a 5 cm wide buffer from surrounding biota. Plugs were attached by pulling 

the leaves through a square piece of 2.5 cm diameter stretch mesh nylon net that was cut to a size that 

was slightly larger than the square plug (Figure 1c). The net was pulled tight over the plug and secured 

to the reef at the edges with marine epoxy. As done for sprigs, the leaves were trimmed to 20 cm in 

length to minimize drag. Three different sizes of plugs (small, 5 cm x 5 cm; medium, 10 cm x 10 cm; 

and large, 20 cm x 20 cm) were transplanted to test whether plug size influenced: (1) survivorship and 

growth (i.e. increase in aerial coverage) of the transplanted plug, and (2) rate of recovery of the donor 

area from which the plug was collected. Six plugs of each size were transplanted to separate plots in 

each of the two sites. 

The collection of plugs resulted in the immediate loss of surfgrass in the donor beds equal to the aerial 

coverage of the plugs. To estimate the recovery of bare patches in the donor bed created by harvesting 

plugs, we marked each donor patch at the time of harvesting and made periodic measurements to 

assess the extent of in-growth from the edges of the bare patches by neighboring rhizomes. The 

recovery of donor patches was determined at the end of the six-month experiment by calculating the 

area of bare space remaining in each donor patch from linear measurements taken with a tape measure.

Efficacy of different methods of restoration 

We estimated the amount of effort (E) per unit transplant spent collecting, preparing and transplanting 

seedlings, sprigs and plugs for both intertidal and subtidal habitats. The effort (i.e., person hours) 

involved in the collection of seedlings was based on the time spent collecting reproductive shoots in 

the field, gathering and cleaning fruits dehisced in seawater aquaria, germinating seeds, and cultivating 

seedlings in laboratory cultures. Effort in preparing seedlings for transplanting consisted of the time 

spent in the laboratory attaching seedlings to nylon lines, while the effort in transplanting seedlings 
Final Study Report – Reed and Holbrook 

 38

was based on the time spent attaching them to the reef (this included clearing the transplant plots on 

the reef of algae and debris). Estimates of effort for sprigs and plugs were based on the time spent 

collecting in the field, trimming leaves in preparation for transplantation, and transplanting units to 

adjacent areas on the reef. In the case of plugs, additional preparation time was spent cutting the 

netting used to secure the plugs and pulling the leaves of the plugs through it. The transport of 

transplant units, the set-up of laboratory cultures, and the mobilization and demobilization of gear and 

assistants are factors that are likely to vary greatly among different restoration projects depending on 

the proximity of the laboratory to the restoration site, and the size of the area to be restored. 

Consequently we excluded these factors in our estimates of effort. 

The efficacy of the three different methods was evaluated by calculating the mean net change in the 

aerial coverage of rhizome of a transplant unit per unit effort measured in person hours. The mean net 

change in aerial coverage of rhizome (A) was calculated as: 

A = TS – (Dinitial – Dfinal), 

where T is the mean aerial coverage of rhizome (cm2

) of the transplant unit six months after 

transplantation, S is the proportion of transplant units surviving six months, Dinitial is the aerial 

coverage of rhizome (cm2) collected from the donor patch, and Dfinal is the mean net change in aerial 

coverage of rhizome (cm2

) in the donor patch six months later. 

The mean net change in the aerial coverage of rhizome of a transplant unit per work hour (CPWH) was 

calculated as: 

CPWH = A / E. 

Analyses

A t-test using Satterthwaite’s approximation for the degrees of freedom (SAS 2001) was used to test 

differences in survivorship between seedlings transplanted to the intertidal vs. the subtidal. 

Survivorship was estimated from twelve plots each of which contained eighteen seedlings. Two by 

two contingency tables were used to evaluate habitat-specific differences in survivorship for sprigs and 

plugs. A two-way fixed factor ANOVA was used to test for the effects of site (intertidal vs. subtidal) 

and restoration method (seedling, sprig, and small, medium and large plugs) on the growth of 

surviving transplants. Differences in percent change in leaf number among treatment means were 

evaluated using Ryan-Einot-Gabriel-Welch multiple range test (SAS 2001). 

The hypothesis that the aerial coverage of rhizome of transplanted sprigs and plugs changed 

significantly during the six months was tested using one-sample, two-tailed, t-tests, where the 

population mean μ was the aerial coverage of rhizome at the beginning of the experiment. Similar 

analyses were done on the donor plots from which sprigs and plugs were harvested to assess whether 

any significant recovery of the donor plots had occurred. Analyses testing the significance of changes 

in the aerial coverage of rhizomes in transplanted seedlings were not done because all seedlings lacked 

rhizomes at the start of the experiment and had zero variance in aerial coverage of rhizome at the end 

of the experiment (the final aerial coverage of rhizome of seedlings was uniformly small and at the 

lower limit of our measurement capabilities). 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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RESULTS 

Survivorship and change in leaf number 

Substantial mortality of seedlings occurred within the first few days of transplanting at both the 

intertidal and subtidal sites, and few of the 432 seedlings survived six months (Figure 2). Survivorship 

was equally poor at both the intertidal and subtidal sites (t16 = 0.98, P = 0.341). Survivorship of sprigs 

and plugs was substantially greater than that of seedlings (Table 1), with sprigs surviving significantly 

better in the subtidal than in the intertidal (71.4 % vs. 47.6 %; χ

2

1 DF = 11.81, P = <0.001). No sprigs 

died as a result of becoming dislodged. Instead, evidence of death was based on necrosis and loss of 

leaves. Plugs had the greatest survivorship, as nearly all were alive after six months, except large 

plugs transplanted to the intertidal where only one of six survived. The five large plugs that died 

became dislodged and disappeared within days after transplanting. 

Production of new leaves by transplant units that survived for six-months was affected by both site and 

the method of restoration. Seedlings, sprigs, and plugs transplanted to the subtidal produced more than 

three times as many new leaves as those transplanted to the intertidal (Figure 3a, F1,79 = 12.93, P 

<0.001). Differences in leaf production among methods were equally large (Figure 3b, F4,79 = 12.93, P 

<0.001). The few seedlings that survived grew well and showed nearly a 300 % increase in the 

number of leaves. Substantial leaf production also occurred in transplanted sprigs and small plugs, but 

was somewhat less than that of seedlings. In contrast, medium and large sized plugs grew poorly and 

actually lost leaves over the course of the experiment. Differences in leaf production among the 

different restoration methods were generally similar at the intertidal and subtidal sites (F4,79 = 1.47. P = 

0.221 for the site x method interaction). 

Rhizome aerial coverage and donor recovery 

Changes in the aerial coverage of rhizome material varied substantially among transplanted seedlings, 

sprigs and plugs (Table 2). Rhizomes of surviving sprigs consistently grew the most. The mean aerial 

coverage of the rhizomes of sprigs transplanted to the intertidal increased by 42% while that 

transplanted to the subtidal increased by 86%. Rhizome growth of the different-sized plugs varied 

inconsistently between the intertidal and subtidal sites. For example, significant increases in rhizome 

coverage were observed in small plugs transplanted to the intertidal, but not in small plugs 

transplanted to the subtidal (Table 2). Conversely, rhizome coverage increased significantly in 

medium plugs transplanted to the subtidal, but not in medium plugs transplanted to the intertidal. 

There was no significant change in the mean rhizome coverage of large plugs transplanted to the 

subtidal, whereas the area covered by rhizomes of the lone surviving large plug in the intertidal 

increased slightly (i.e. 9%). Rhizomes were typically poorly developed in six-month old seedlings. 

Nonetheless, the few seedlings that survived in the intertidal and subtidal had developed small 

rhizomes by the end of the experiment. 

Striking differences were observed in the recovery of donor plots from which sprigs and plugs were 

harvested (Table 3). In the case of sprigs, full recovery was observed at both the intertidal and subtidal 

sites as the re-growth of cut rhizomes more than compensated for the loss incurred from harvesting. In 

contrast, harvesting plugs led to significant additional losses of surfgrass in areas adjacent to donor 

plots. These losses were observed within a few weeks of harvesting, and appeared to result from water 

motion that undermined the edges of cut rhizomous mats that were exposed when the plugs were 
Final Study Report – Reed and Holbrook 

 40

removed. These subsequent losses were substantial, ranging from 67% to 533% of the initial donor 

area, and they were generally larger in the intertidal than in the subtidal. Large plugs taken from the 

intertidal had the largest mean net loss from harvesting. However, because of high variability among 

replicate donor plots, these were the only type of plug whose subsequent losses of surfgrass were not 

statistically significant (Table 3). 

Efficacy of different methods of restoration 

Overall, restoration using seedlings and sprigs required less effort than restoration with plugs (Figure 

4). Seedlings, which were reared in the laboratory and attached to strings prior to transplanting, 

required more effort for transplant preparation than for collecting or transplanting. In contrast, 

relatively little effort was allocated to transplant preparation for sprigs and plugs; most of the effort for 

sprigs and plugs involved collecting and transplanting. In general, less effort was needed to collect and 

transplant sprigs and plugs in the subtidal than in the intertidal. This occurred because material for 

transplanting was more readily available in the subtidal resulting in shorter collection times. 

Moreover, transplanting sprigs and plugs required more effort in the intertidal because of the increased 

difficulty of clearing sand and debris there. 

The change in area of surfgrass habitat per unit effort varied tremendously among the methods tested 

(Table 4). The use of sprigs proved to be the most effective method for restoring surfgrass to both the 

intertidal and subtidal sites. The mean change in aerial coverage of rhizome per work hour (CPWH) 

for sprigs in the subtidal was more than five times that in the intertidal. This was a result of greater 

increases in net rhizome coverage and smaller effort involved in transplanting at the subtidal site. The 

small values of CPWH observed for seedlingsreflected the high mortality and small gains in rhizome 

coverage observed over a six-month period. Interestingly, CPWH for all three sizes of plugs was 

negative for both the intertidal and subtidal sites. The negative values for plugs resulted from the 

subsequent losses of surfgrass to donor populations as a result of harvesting. Even if these subsequent 

losses were discounted, CPWH for medium and large plugs would be low due to the limited (and in 

some cases negative) growth of transplanted plugs, coupled with the relatively large amount of effort 

required for transplant. 

DISCUSSION 

Techniques permitting large-scale restoration efforts have been developed and tested for a few seagrass 

species that grow rapidly and occupy sheltered habitats, (e.g., Fonseca et al. 1998; Orth et al. 1999; 

Short et al. 2002). For example, restoration programs for Zostera marina now can include such 

elements as economic and ecological analyses to determine the scale of the restoration (Fonseca et al. 

2000), use of site selection models to identify optimal areas for transplant (Short et al. 2002), and 

employment of a range of transplant techniques involving various life stages (adult plants, seeds, or 

seedlings; Fonseca et al. 1998, Orth et al. 1999). However, for many seagrasses, much less progress 

has been made. For example, in Western Australia, seagrasses (Amphibolis sp. and Posidonia sp.) 

normally live in areas of high water motion, and restoration attempts in these habitats consistently 

failed until recently, when underwater harvesting and planting machines that permit extraction and 

planting of seagrass plugs that are sufficiently large to withstand storm damage were developed (Paling 

et al. 2001a, 2001b). Surfgrass (P. torreyi), which occupies exposed rocky coasts of western North 

America, is another example of a species for which restoration strategies have been lacking. Due to 

the difficulty of anchoring transplant units to the rocky substrata in turbulent water, few attempts have 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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been made to explore transplanting techniques, and the lack of developed techniques has prevented 

efforts of large-scale restoration. 

Although the majority of attempts to restore seagrasses have involved the use of older life stages 

(reviewed in Thorhaug 1986; Thom 1990), concerns about donor bed recovery, coupled with the fact 

that harvesting large numbers of early life stages (such as seeds) would have relatively little impact on 

donor populations, have led to increased interest in the use of early life stages for restoration (Balestri 

et al. 1998; Orth et al. 2000; Holbrook et al. 2002). Like many other seagrass species, P. torreyi tends 

to produce large numbers of seeds (up to 10,000 per square meter of surfgrass bed during the annual 

flowering season; Williams 1995). Typically, few seeds develop into seedlings (Stewart 1989; 

Williams 1995; Blanchette et al. 1999, Holbrook et al. 2000), and early survival of seedlings is poor 

(Blanchette et al. 1999; Holbrook et al. 2000). Many seeds are consumed by predators, either prior to 

their release from the spadix or afterwards (Holbrook et al. 2000). Turbulent conditions in the surf 

zone frequently cause surfgrass seedlings to become dislodged from their host plants or suffer abrasion 

from nearby vegetation (Blanchette et al. 1999). Burial by sand and desiccation in the intertidal zone 

are additional causes of mortality of young seedlings (Bull 2002). Recently-developed techniques for 

harvesting seeds of P. torreyi, and for laboratory storage, germination and propagation (Reed et al. 

1998), make it possible to consider using seedlings of this species for restoration. 

Results from this study raise some concern as to whether the survival bottlenecks in the early life 

history stages can be overcome as part of the restoration strategy. Our use of nylon line as an 

attachment host attempted to minimize dislodgement of seedlings. Dislodgement of the strings during 

the first few days after transplanting accounted for approximately 20% and 14% of the total mortality 

of seedlings transplanted to the intertidal and subtidal sites, respectively (Bull 2002). Strings that 

remained glued to the reef appeared to be quite adept at retaining seedlings as most remained attached 

to the strings even after their shoots were gone. The vast majority of mortality resulted from factors 

that caused seedlings to die in place. The specific causes of seedling mortality during our study 

remain unknown. Afternoon low tides undoubtedly create harsh conditions for seedlings in the 

intertidal zone and desiccation and high temperatures likely contribute to the mortality of seedlings in 

this habitat. Such factors are not important in the subtidal, yet survivorship was equally poor in this 

habitat. Small herbivorous crustaceans, mollusks and fish are commonly abundant in intertidal and 

subtidal habitats where surfgrass is found and these grazers are very capable of consuming the small 

delicate leaves of surfgrass seedlings (Holbrook et al. 2000). Despite the poor survivorship of 

seedlings, those that did survive grew extremely well, increasing their leaf numbers by nearly four fold 

in six months. This suggests that there is promise in using early life stages of surfgrass for restoration, 

especially when the small impacts on the beds caused by collecting seeds are taken into account. 

Additional research is warranted to develop methods to reduce losses of transplanted seedlings. 

Harvesting plant material from natural, healthy beds can be a large concern for resource managers 

charged with restoring damaged seagrass populations, especially in the case of slow-growing species 

such as Thalassia testudinum and P. torreyi. Our results indicate that such concerns are very well 

justified for P. torreyi. Although survival of plugs was generally high, they grew poorly, and more 

importantly, harvesting plugs resulted in additional subsequent losses to the donor population. The cut 

rhizomes at the edges of the holes became eroded by waves and were easily removed from the rocky 

substrate. Consequently, the holes created by collecting plugs became significantly larger during the 

six months following harvesting. This was most pronounced at the intertidal site where wave forces 

are expected to be greater. Recovery via in-growth from neighboring rhizomes was slow in donor 
Final Study Report – Reed and Holbrook 

 42

plots and after 18 months, surfgrass had regrown to occupy only about 55 % of area of the harvested 

plots (Bull 2002). For these reasons, it may be unwise to collect plugs of material from surfgrass beds 

for use in restoration. By contrast, sprigs survived and grew reasonably well, and re-growth of 

rhizomes that were cut to obtain sprigs for transplanting was rapid. The patterns of growth and 

survival of transplants and of recovery of donor plots, combined with the amount of effort involved, 

revealed that the largest gain in rhizome coverage per unit of effort occurred when sprigs were used. 

Moreover, sprigs suitable for transplanting required relatively little effort to prepare and were abundant 

at the study sites (Bull 2002), suggesting that collection of sprigs for transplanting would not have a 

large impact to existing P. torreyi beds. Collectively these features rendered sprigs the most 

acceptable form for use in restoration. 

P. torreyi occurs along a depth gradient, from the intertidal to the shallow subtidal zone. As such, it 

encounters a wide range of physical conditions, and knowledge of the tolerance of the species to 

factors such as light, sedimentation, temperature, and wave generated water motion provides insight 

into possible restoration strategies. Not surprisingly, the efficacy of the three restoration methods that 

we tried varied considerably between the intertidal and subtidal sites. In general, survivorship and 

growth of transplants and the recovery of donor plots all tended to be higher in the subtidal than in the 

intertidal, and the effort expended in transplanting was also less in the subtidal. That all three methods 

of restoration varied consistently in this regard suggests that while restoration success in surfgrass is 

likely to vary along a depth gradient, it may not require different techniques be used in different 

depths. 

CONCLUSION 

Results from our research suggest that efforts to restore damaged populations of P. torreyi are highly 

dependent on the type of enhancement technique used. The evaluation of several techniques revealed 

that transplanting sprigs was the most effective means of producing a net increase in area of surfgrass 

habitat per unit effort. This outcome was affected by several factors. While factors affecting favorable 

growth and survival were significant elements, cost-effectiveness and recovery of donor plots also 

played important roles in determining the overall success of a technique. Depth also appeared to affect 

outcome, with subtidal transplants generally outperforming intertidal transplants for the same 

technique. The development of techniques that allow transplants to better withstand the harsh 

conditions of the intertidal should benefit restoration efforts in this zone. 

ACKNOWLEDGEMENTS 

We thank Mike Anghera for his help and encouragement in all phases of this work. We also thank the 

many individuals who assisted us in the field, especially J. Blythe, C. Boch, M. Brinkman, J. Bunch, L. 

Deeb, M. Fuchs, C. Galst, A. Quinn, H. Rodrigues, A. Rossman, and E. Stephens. S. Hodges 

commented on a earlier draft of the manuscript. The research was supported by the Coastal 

Toxicology Component of the University of California Toxic Substances Research and Training 

Program, the County of Santa Barbara, CA, the Minerals Management Service of the U.S. Department 

of the Interior (MMS Agreement No. 14-35-00011-30758) and the National Science Foundation (BIR 

94-13141, OCE99-82105). The views and conclusions contained in this document are those of the 

authors and should not be interpreted as necessarily representing the official policies, either expressed 

or implied, of the U.S. Government. 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 43

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Blanchette, C. A., S. E. Worcester, D. Reed, and S. J. Holbrook. 1999. Algal morphology, flow, and 

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Bull, J. S., 2002. An experimental evaluation of different methods of restoring surfgrass (Phyllospadix 

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for mitigation. Marine Ecology Progress Series 65:251-264. 

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Coastal Ocean Office, Silver Spring, MD, 222 pp. 

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seagrass restoration: How much is enough and why? Ecological Engineering 15:227-237. 

Fuss, C. H., and J. A. Kelly. 1969. Survival and growth of seagrasses transplanted under artificial 

conditions. Bulletin of Marine Science 19(2):351-365. 

Harlin, M. M. 1975. Epiphyte-host relations in seagrass communities. Aquatic Botany 1:125-131. 

Harwell, M. C., and R. J. Orth. 1999. Eelgrass (Zostera marina L.) seed protection for field 

experiments and implications for large-scale restoration. Aquatic Botany 64:51-61. 

Holbrook, S. J., D. C. Reed, K. Hansen, and C. A. Blanchette. 2000. Spatial and temporal patterns of 

predation on seeds of surfgrass Phyllospadix torreyi. Marine Biology 136:739-747. 
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Holbrook, S. J., D. C. Reed, and J. S. Bull. 2002. Survival experiments with outplanted seedlings of 

surfgrass (Phyllospadix torreyi) to enhance establishment on artificial structures. ICES Journal of 

Marine Science 59:S350-S355. 

Kelly, J. A., C. M. Fuss, and J. R. Hall. 1971. The transplanting and survival of turtlegrass, Thalassia 

testudinum, in Boca Ciega Bay, Fla. Fisheries Bulletin 69:273-280. 

Larkum, A. W. D., A. J. McComb, and S. A. Shepherd. 1989. Biology of seagrasses: a treatise on the 

biology of seagrasses with special reference to the Australian region. New York, Elsevier. 

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and shorebirds on the Forth Estuary, eastern Scotland. Aquatic Conservation: Marine and 

Freshwater Ecosystems. 2(3):211-222. 

Morand, P., and X. Briand. 1996. Excessive growth of macroalgae: a symptom of environmental 

disturbance. Botanica Marina 39:491-516. 

Orth, R. J., M.C. Harwell, and J. R. Fishman. 1999. A rapid and simple method for transplanting 

eelgrass using single, unanchored shoots. Aquatic Botany 64:77-85. 

Orth, R. J., M. C. Harwell, E. M. Bailey, A. Bartholomew, J. T. Jawad, A. V. Lombana, K. A. Moore, 

J. M. Rhode, and H. E. Woods. 2000. A review of issues in seagrass seed dormancy and 

germination: implications for conservation and restoration. Marine Ecology Progress Series 

200:277-288. 

Paling, E. I., M. van Keulen, K. Wheeler, J. Phillips, and R. Dyhrberg. 2001a. Mechanical seagrass 

transplantation in Western Australia. Ecological Engineering 16:331-339. 

Paling, E. I., M. van Keulen, K. D. Wheeler, J. Phillips, R. Dyhrberg, and D. A. Lord. 2001b. 

Improving mechanical seagrass transplantation. Ecological Engineering 18:107-113. 

Phillips, R. C. 1974. Transplantation of seagrasses, with special emphasis on eelgrass, Zostera 

marina L. Aquaculture 4:161-176. 

Phillips, R. C. 1979. Ecological Notes on Phyllospadix (Potamogetonaceae) in the northeast Pacific. 

Aquatic Botany 6:159-170. 

Reed, D. C., S J. Holbrook, E. Solomon, and M. Anghera. 1998. Studies on germination and root 

development in the surfgrass Phyllospadix torreyi: implications for habitat restoration. Aquatic 

Botany 62:71-80. 

SAS Institute Inc. 2001. The SAS System for Windows, Release 8.02, Cary, North Carolina, USA. 

Santour, B., and J. Castel. 1995. Comparative spring distribution of zooplankton in macrotidal 

European estuaries. Hydrobiologia 311:139-151. 

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Hydrobiologia 363:73-79. 

Sheridan, P., G. McMahan, K. Hammerstrom, and W. Pulich, Jr. 1998. Factors affecting restoration 

of Halodule wrightii to Galveston Bay, Texas. Restoration Ecology 6:144-158. 

Short, F. T., and D. M. Burdick. 1996. Quantifying eelgrass habitat loss in relation to housing 

development and nitrogen loading in Waquoit Bay, Massachusetts. Estuaries 19:730-739. 

Short, F. T., and S. Wyllie-Echeverria. 1996. Natural and human-induced disturbance of seagrasses. 

Environmental Conservation 23:17-27. 

Short, F.T., R.C. Davis, B.S. Kopp, C.A. Short, D.M. Burdick. 2002. Site-selection model for optimal 

transplantation of eelgrass Zostera marina in the northeastern US. Marine Ecology Progress 

Series 227:253-267. 

Stewart, J. G. 1989. Maintenance of a balanced and shifting boundary between the seagrass 

Phyllospadix and algal turf. Aquatic Botany 33:223-241. 

Stewart, J. G., and B. Meyers. 1980. Assemblages of algae and invertebrates in southern California 

Phyllospadix-dominated intertidal habitats. Aquatic Botany 9:37-94. 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 45

Thom, R. M. 1990. A review of eelgrass (Zostera marina L.) transplanting projects in the Pacific 

Northwest. The Northwest Environmental Journal 6:121-137. 

Thorhaug, A. 1986. Review of Seagrass Restoration Efforts. Ambio 15:110- 117. 

Walker, D. I., R. J. Lukatelich, G. Bastyan, and A. J. McComb. 1989. Effect of boat moorings on 

seagrass beds near Perth, Western Australia. Aquatic Botany 36:69-77. 

Williams, S. L. 1995. Surfgrass (Phyllospadix torreyi) reproduction: reproductive phenology, 

resource allocation, and male rarity. Ecology 76:1953-1970. 

Williams, S. L., and C. A. Davis. 1996. Population genetic analyses of transplanted eelgrass (Zostera 

marina) beds reveal reduced genetic diversity in southern California. Restoration Ecology 4:163-

180. 

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in southern Florida. Aquatic Botany 2:127-139. 
Final Study Report – Reed and Holbrook 

 46

Table 1. Survivorship of transplanted surfgrass after six months at an intertidal and subtidal site. Data 

for seedlings are means ± 1 SE. 

Method Number transplanted Survivorship (%)

Intertidal 

Seedling 12 plots of 18 seedlings 2.3 ± 1.3 

Sprig 42 47.6 

Plug (small) 6 100 

 (medium) 6 100 

 (large) 6 16.7 

Subtidal 

Seedling 12 plots of 18 seedlings 0.9 ± 0.6 

Sprig 42 71.4 

Plug (small) 6 100 

 (medium) 6 100 

 (large) 6 100 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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Table 2. Mean aerial coverage of rhizome material (cm2

) of transplant units at the end of six 

months. μ represents the rhizome aerial coverage (cm2

) of the transplant unit at the beginning the 

experiment. P is the probability that the mean is ≠ μ. Statistically significant P-values (i.e., 

<0.05) are in bold. NA indicates that data did not meet the assumptions for a t-test or that a t-test 

was not applicable. 

 

Method Mean SE μ df t P 

Intertidal 

 Seedling 0.5 0 0 NA NA NA 

Sprig 7.1 0.9 5 18 2.452 0.021 

Plug (small) 56.5 11.4 25 5 2.771 0.042 

 (medium) 86.8 18.4 100 5 -0.717 0.401 

 (large) 437 NA 400 0 NA NA 

Subtidal 

Seedling 0.5 0 0 NA NA NA 

Sprig 9.3 0.9 5 29 4.845 <0.001 

Plug (small) 33.7 4.4 25 5 1.962 <0.001 

 (medium) 146.2 12.1 100 5 3.807 0.013 

 (large) 388.8 57.6 400 5 -0.194 0.858 
Final Study Report – Reed and Holbrook 

 48

Table 3. Mean net change in the aerial coverage of rhizomes (cm2

) of the donor plots from 

which the different transplant units were harvested six months after donor collection. μ

represents the rhizome coverage (cm2

) of the donor plot at the beginning the experiment. P is the 

probability that the mean is ≠ μ. Statistically significant P-values (i.e., <0.05) are in bold. NA 

indicates that a t-test was not applicable. Negative values indicate the area of bare space in the 

donor plot increased after donor collection. 

Method Mean SE μ df t P

Intertidal 

Seedling 0 0 0 NA NA NA 

Sprig 2.67 0.61 5 5 3.846 0.021 

Plug (small) -70.1 33.23 25 5 -2.861 0.031 

 (medium) -532.7 214.16 100 5 -2.954 0.036 

 (large) -1065.8 620.47 400 4 -2.362 0.080 

Subtidal 

Seedling 0 0 0 NA NA NA 

Sprig 2.92 1.0 4 5 6 2.011 0.101 

Plug (small) -16.64 9.74 25 3 -4.274 0.031 

 (medium) -252.19 107.41 100 3 -3.279 0.049 

 (large) -670.00 205.82 400 2 -5.199 0.015 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 49

Table 4. Mean net change in aerial coverage of rhizome material (A), effort involved in 

transplanting per unit transplant (E), and net change in the coverage of rhizome area per work 

hour (CPWH) for the different methods of restoration at an intertidal and subtidal site. See text 

for details of how A, E and CPWH were calculated. 

Method A 

(cm2)

E 

(h)

CPWH 

(cm2 rhizome·work h-1)

Intertidal 

Seedling 1.0 X 10-2 0.27 0.04 

Sprig 1.05 0.25 4.2 

Plug (small) -38.60 0.57 -67.72 

 (medium) -545.90 0.73 -747.81 

 (large) -1392.82 1.00 -1392.82 

Subtidal 

Seedling 4.5 X 10-3 0.25 0.02 

Sprig 4.56 0.18 25.33 

Plug (small) -7.94 0.47 -16.89 

 (medium) -205.99 0.58 -355.16 

 (large) -681.20 0.73 -933.15 
Final Study Report – Reed and Holbrook 

 50

 

Figure 1. Three methods of restoring P. torreyi tested in this study. a) seedling attached to 

braided nylon line, b) sprig glued to the reef with marine epoxy, and c) plug woven through 

nylon net fastened to the reef by marine epoxy. 

b)

c)

a)
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 51

Days after transplanting

0 50 100 150 200

% Surviving

0

20

40

60

80

100

intertidal 

subtidal 

Figure 2. Survivorship of seedlings transplanted to the intertidal and subtidal sites. 
Final Study Report – Reed and Holbrook 

 52

intertidal subtidal

% change in leaf number

0

50

100

150

200

seedling sprig plug(s) plug(m) plug(l)

% change in leaf number

-100

0

100

200

300

400

A

B

B

A

AB

C C

a)

b)

Figure 3. The effects of a) site and b) restoration method on the percentage change in the 

number of leaves of surviving transplants for the different methods of restoration [(s), (m) and 

(l) refer to small, medium and large plugs Data are means ± 1 SE. Means sharing the same 

letter are not significantly different from each other based on Ryan-Einot-Gabriel-Welch 

multiple range test. 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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a) Intertidal

seedling sprig plug(s) plug(m) plug(l)

Effort (h) / transplant unit

0.0

0.2

0.4

0.6

0.8

1.0

collection 

preparation 

transplantation 

b) Subtidal

seedling sprig plug(s) plug(m) plug(l)

Effort (h) / transplant unit

0.0

0.2

0.4

0.6

0.8

1.0

 

Figure 4. The amount of effort allocated to collection, preparation and transplantation for the 

different methods of restoration for a) intertidal and b) subtidal sites [(s), (m) and (l) refer to 

small, medium and large plugs]. See text for details on the work entailed in each category of 

effort for the different restoration methods. 
Final Study Report – Reed and Holbrook 

 54
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 55

UNIVERSITY OF CALIFORNIA 

Santa Barbara 

An Experimental Evaluation of Different Methods of Restoring 

Surfgrass (Phyllospadix torreyi) 

A thesis submitted in partial satisfaction 

of the requirements for the degree of Master of Arts 

in Ecology, Evolution, and Marine Biology 

by 

J. Scott Bull 

Committee in charge: 

Professor Sally J. Holbrook, Co-chair 

Research Biologist Daniel C. Reed, Co-chair 

Associate Professor Scott Hodges 

June 2002 

Copyright © 2002 

by 

 J. Scott Bull 
Final Study Report – Reed and Holbrook 

 56

ABSTRACT 

AN EXPERIMENTAL EVALUATION OF DIFFERENT METHODS OF RESTORING 

SURFGRASS (PHYLLOSPADIX TORREYI) 

By 

J. Scott Bull 

Surfgrass, Phyllospadix spp., is an ecologically important species that provides habitat for a 

diverse array of organisms in the intertidal and sublittoral zones of rocky shores. In southern 

California, Phyllospadix torreyi can be adversely affected by a range of natural and 

anthropogenic activities. Developing effective methods for restoring damaged surfgrass habitat is 

of great importance, yet few attempts have been made and none have investigated the efficacy of 

using different life stages. Here I evaluated several techniques for restoring populations of 

surfgrass in intertidal and subtidal habitats using 1) outplanted laboratory-reared seedlings, 2) 

transplanted rhizome sprigs (collected in situ from within the existing bed) and 3) transplanted 

rhizome plugs. I calculated net change in surfgrass habitat for each method after six months 

taking into account the recovery or additional losses from the donor population, and amount of 

effort required. Outplanted seedlings survived poorly and had minimal rhizome growth over the 

six-month study period for both intertidal and subtidal sites yet on average showed a 275% 

increase in leaf number. The survivorship of transplanted plugs was high in both intertidal and 

subtidal habitats; however, additional disturbances to the donor population caused a substantial 

net loss in surfgrass habitat using this technique. Sprigs transplanted in the subtidal had higher 

survivorship than those transplanted to the intertidal with intertidal (71.4% vs. 47.6%), and 

showed the highest increase in area of surfgrass habitat (42% and 86% for intertidal and subtidal 

transplants, respectively). Of the three techniques, transplanted sprigs showed the greatest overall 

increase in surfgrass habitat per unit effort for both subtidal and intertidal habitats. This research 

suggests that the use of sprig transplants may be the most effective approach for restoration of P. 

torreyi. 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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CHAPTER 1

AN EXPERIMENTAL EVALUATION OF DIFFERENT METHODS OF RESTORING 

SURFGRASS (PHYLLOSPADIX TORREYI) 

INTRODUCTION 

A wide variety of biological, environmental and logistical issues must be considered during 

restoration of long-lived species of plants that have been damaged or destroyed. A number of 

factors could affect the choice of methods for restoring such species including: (1) ease of 

propagation, (2) constraints on collection, cultivation and transplantation, (3) fitness of 

transplanted individuals, (4) desired genetic diversity of the restored population, and (5) the 

amount of damage suffered by donor populations and the likelihood of recovery. Furthermore, 

the potential restoration methods for a given species may vary depending on the environmental 

conditions experienced at the restoration site. Many restoration projects often must proceed 

without detailed consideration of all the pertinent issues, which can make it difficult to evaluate 

their long-term success and cost-effectiveness. 

One case in point involves the restoration of seagrasses, whose populations have been degraded 

by nutrient loading (Short & Burdick 1996; Short & Wyllie-Echeverria 1996), polluted waste 

from sewage and industrial discharges (Sautour & Castel 1995; Morand & Briand 1996; Clark 

1997; Schiewer 1998; Castel et al. 1996), coastal development and offshore construction 

(Cambridge & McComb 1984; Short et al. 1991; McLusky et al. 1991; Sheridan et al. 1998), and 

recreational and commercial boating and fishing (Zieman 1976; Walker et al. 1989; Dawes et al. 

1997). Seagrasses typically are a dominant organism in the areas in which they occur, providing 

an important source of food and shelter for a variety of nearshore organisms (Harlin 1975; 

Stewart & Myers 1980; Fonseca et al. 1990; WyIlie-Echeverria & Phillips 1994). Their high 

ecological importance, coupled with their susceptibility to damage from a range of human 

activities and natural disturbances, have sparked much interest in developing effective methods 

for restoring damaged populations (Thorhaug 1986; Larkum et al. 1989; Edgar 1990). 

Previous attempts to restore seagrass populations often have relied on transplanting older life 

stages that were collected from healthy stands (Thorhaug 1986; Thom 1990; Orth et al. 1999, 

2000; Williams & Davis 1996; Paling et al. 2001a, b). In many cases, transplanting techniques 

have been successful in promoting the establishment of new plants (Fuss and Kelly 1969; Kelly 

et al. 1971; Phillips 1974; Fonseca et al. 1994; Thorhaug 1986; Thom 1990; Williams & Davis 

1996; Balestri et al. 1998). Although cost-effectiveness of different planting techniques has been 

examined (e.g., Thorhaug 1986), there have been few attempts to measure the damage to donor 

populations that results from collecting materials for use in transplanting. Hence, there is 

growing concern among resource managers that for some species, restoration projects have the 

potential to cause long-term losses to otherwise healthy populations. Such concern has prompted 

studies to explore the use of seeds and cultivated seedlings in restoration (Balestri et al. 1998; 

Harwell & Orth 1999; Holbrook et al. 1999); however, relatively little research on this topic has 

been done to date (Orth et al. 2000). 
Final Study Report – Reed and Holbrook 

 58

Restoration of sea grasses has been carried out in many areas of the world on a variety of species, 

but in the United States efforts have focused on species such as Halodule wrightii and Zostera 

marina that occupy shallow, soft-bottom habitats (Thom 1990). Surfgrasses (i.e., seagrasses in 

the genus Phyllospadix) pose special challenges for restoration because the transplanting 

techniques that have been developed for other seagrasses are not appropriate for them. Unlike 

most seagrasses that live in soft sediments of protected bays or estuaries, surfgrasses grow on 

rocky shores of exposed coasts. Adventitious roots from the rhizome secure the plant to the rocky 

substratum (Chrysler 1907; den Hartog 1970; Phillips 1979; Tomlinson 1980; Cooper & McRoy 

1988). Their penchant for growing on rocks in wave swept areas greatly complicates efforts to 

restore them because successful transplantation depends not only on the ability to grow following 

relocation, but also on the ability of transplanted individuals to avoid becoming dislodged by the 

forces of breaking waves. Because surfgrass rhizomes are not inherently “sticky”, this latter 

requirement invariably necessitates the use of a glue or epoxy to secure a transplanted individual 

to rock. Another factor that complicates the restoration of surfgrass is that populations typically 

extend from the low intertidal into the shallow subtidal and thus are subjected to a wide range of 

biological (e.g. competition, grazing) and physical (e.g., temperature, desiccation, waves, light) 

conditions (Turner 1983, 1985; Stewart 1989; Blanchette et al. 1999; Holbrook et al. 2000) that 

influence their growth and survivorship. This may dictate the use of different methods for 

restoration of plants at different depths. To date, there has been little progress in the development 

of efficient strategies that enable restoration of surfgrass populations (Holbrook et al. 2002). 

Surfgrass is a clonal plant that produces copious amounts of seeds whose germination is easily 

controlled in laboratory culture (Williams 1995; Reed et a!. 1998). As such, it has the potential to 

be propagated readily from seeds, sprigs, or plugs. Such flexibility could be of significant value 

in restoration if the relative performance of the different forms varies along the depth gradient. 

Here I experimentally investigated the cost effectiveness of restoring surfgrass from seedlings, 

sprigs and plugs at two different depths with the goal of determining the optimal method(s) for 

restoring damaged populations. Specifically, I evaluated the efficacy of the three methods of 

restoration based on: 1) the growth and survivorship of transplanted individuals, (2) the effort 

involved in collecting, preparing and transplanting, and (3) the residual damage to donor 

populations. 

METHODS 

This study compared the efficacy of three methods of restoring populations of surfgrass 

(Phyllospadix torreyi) to intertidal and shallow subtidal reefs near Santa Barbara, CA. The three 

methods were: (1) seedlings cultivated in the laboratory and outplanted to the field, (2) sprigs of 

actively growing rhizome tips collected in the field and transplanted to the study areas, and (3) 

plugs of rhizomous mats collected in the field and transplanted to the study areas. Intertidal 

studies were conducted at More Mesa Reef (34°25’N, l19°57’W), a broad, gently sloping, wavecut bench fractionated by sand channels. Patches of the red algae Corallina vancouveriensis, 

Gelidium purpurascens, and Chondracanthus canaliculatus [which serve as attachment sites for 

surfgrass seeds (Blanchette et al. 1999)] were common in the study area. P. torreyi formed dense 

beds on most of the emergent reef in the low-intertidal zone to the shallow subtidal zone at More 

Mesa Reef. Transplanted seedlings, sprigs and plugs were placed in bare spaces on the reef 

adjacent to P. torreyi. Subtidal studies were done at Mohawk Reef (34°24’ N, 119°44’ W) where 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 59

P. torreyi forms large, patchy beds on broad, gently sloping benches that are interspersed with 

stands of coralline algae consisting primarily of Bossiella orbigiana and Corallina officinalis. 

Seedlings, sprigs and plugs at this site were transplanted to depths of 2.5 to 4 m below MMLW 

in areas cleared of coralline algae that were adjacent to established surfgrass beds. 

Transplant experiments using all three methods were initiated in the late summer and fall 

months, the time of year when most surfgrass seeds are released and germinate in Santa Barbara 

County (Holbrook and Reed unpublished data). All experimental transplants were followed for 

six months. The efficacy of each method of restoration was evaluated using data collected on 

survivorship and growth of the transplants after six months, recovery of the donor population 

from which transplants were collected, and the amount of effort (i.e. time) involved in 

transplanting. Transplants were considered dead if after six months they had no leaves or were 

removed from the substrate. The growth of surviving transplants was estimated as the change in 

rhizome area over the course of the six-month experiment. The percentage change in the number 

of leaves after six months ([(final number of leaves — initial number of leaves) / initial number 

of leaves] * 100) was used to assess the condition of surviving transplants. 

Seedlings 

Seedlings used in this study were germinated from seeds obtained from reproductive shoots of 

mature female P. torreyi plants collected in September 2000 at the two study sites and other nearby 

intertidal and subtidal locations within 15 Km of the sites. Reproductive shoots were cut several 

centimeters above the rhizome and their collection did not result in the loss of surfgrass habitat. 

Upon collection, reproductive shoots were transported to the marine biological laboratory at 

University of California, Santa Barbara where they were placed in a flow through seawater tank 

until fruits (hereafter referred to as seeds) dehisced (about 1 month). Dehisced seeds were placed in 

clear aquaria containing filtered seawater (0.2μm) enriched with nutrient stock solution (Provosoli; 

1968). Aquaria were maintained at 15°C at an irradiance of 40-50 μE m-2 

s

-1 using a 14:10 h L:D 

photoperiod under mild agitation. Culture media were changed weekly and seeds were cleaned and 

rinsed with dionized water to inhibit fouling. Under these conditions, seeds germinated within one 

month of dehiscence (Reed et al. 1998). At the time of outplanting (approximately one month postgermination) seedlings lacked rhizomes and consisted of a single leaf approximately two cm in 

length that was firmly attached to the endocarp of the fruit. 

I attached each seedling to a 7 cm long piece of braided nylon line (1 mm diameter) in the 

laboratory to facilitate outplanting to the field. Seedlings were attached to the line by inserting one 

of the arms of the fruit into an opening in the line made by untwisting the braids one-half turn 

(Figure la). Tiny bristles along the inside arm of the fruit hooked onto one of the braids, locking the 

seedling in place once the line was relaxed and the opening closed. Once attached to the nylon line, 

seedlings were put into re-sealable plastic bags containing seawater and transported to the field in 

coolers. Seedlings attached to nylon line were outplanted to experimental plots 30 cm x 30 cm in 

area at the intertidal and subtidal study sites in November 2000 by fastening the ends of each nylon 

line directly to the reef using Z-Spar A788 marine epoxy putty. Eighteen seedlings were outplanted 

in a uniform grid to each of 12 plots at each of the two sites. All experimental plots were located 

adjacent to healthy stands of surfgrass and were cleared of algae and sand prior to outplanting to 

facilitate attachment with epoxy. Branches of coralline algae growing adjacent to the plots were 

trimmed to reduce abrasion and dislodgement of seedlings. 
Final Study Report – Reed and Holbrook 

 60

Sprigs 

I transplanted apical tips of actively growing rhizomes of P. torreyi from established surfgrass 

beds to evaluate the feasibility and effectiveness of using sprigs to restore damaged populations 

of surfgrass. Sprigs used in this study were harvested from established beds at the intertidal and 

subtidal sites in November 2000, and immediately transplanted to adjacent areas lacking 

surfgrass. To harvest sprigs, an unbranched tip was carefully cut from an actively growing 

rhizome with a sharp knife. Care was taken to minimize damage to the rhizome roots. Harvested 

sprigs were five cm in length. Leaf numbers varied from 5 to 36 (mean 11.9 ± 0.9 SE) for 

subtidal transplants and 12 to 51 leaves (mean 26.6 ± 1.5 SE) for intertidal transplants. Sprigs 

were transplanted to experimentally cleared areas by attaching the cut end of the sprig to the reef 

using marine epoxy (Figure 1b). At least 1.5 cm of the actively growing apical end of each sprig 

was exposed and not in contact with the epoxy. The leaves of transplanted sprigs were trimmed 

to 20 cm in length prior to attachment to minimize drag and reduce the chance of dislodgement 

while the epoxy hardened. Forty-two sprigs were transplanted to each of the two sites. 

The collection of sprigs resulted in a small loss of surfgrass from the donor site. To measure 

recovery from this loss, a reference marker was glued to the reef next to the cut end of each 

donor rhizome (i.e., a rhizome from which a sprig was harvested). Recovery was estimated as the 

area of new rhizome that grew from the cut end of the donor rhizome. Because I was not able to 

relocate many of the donor rhizomes at the end of the study, only six and nine donor rhizomes 

were used to calculate recovery from harvesting sprigs from the subtidal intertidal and sites, 

respectively. 

Plugs 

The feasibility and effectiveness of using clumps of mature surfgrass to restore damaged 

populations was evaluated at the intertidal and subtidal sites beginning in August 1999. Square 

plugs of intertwined rhizomes and leaves were harvested from the middle of an established bed 

of P. rorreyi using a wide bladed putty knife and transplanted to adjacent areas lacking surfgrass. 

Plugs were attached to the reef by pulling the leaves through a square piece of 2.5 cm diameter 

stretch mesh nylon net that was cut to a size that was slightly larger than the square plug (Figure 

1c). The net was pulled tight over the plug and secured to the reef at the edges with marine 

epoxy. Care was taken to insure that the plugs did not come into contact with the epoxy. The 

leaves of all plugs were trimmed to 20 cm in length prior to attachment to minimize drag and 

reduce the chance of dislodgement while the epoxy hardened. Three different sizes of plugs 

(small, 5 cm x 5 cm medium, 10 cm x 10 cm and large, 20 cm x 20 cm) were transplanted to test 

whether plug size influenced (1) the survivorship and growth of the transplanted plug, and (2) the 

rate of recovery of the donor area from which the plug was collected. Six plugs of each size were 

transplanted to each of the two sites. 

The collection of plugs resulted in the immediate loss of surfgrass habitat in the donor beds equal 

to the rhizome area of the plugs (i.e., 25 cm2

, 100 cm2 and 400 cm2 for small, medium and large 

plugs, respectively). To facilitate estimates of the recovery of the bare patches in the donor bed 

created by harvesting plugs, I marked each donor patch at the time of harvesting and made 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 61

periodic observations during the experiment to assess the extent of in-growth from the edges of 

the bare patches by neighboring rhizomes. The recovery of donor patches was determined at the 

end of the six-month experiment by measuring the area of bare space remaining in each donor 

patch. 

Figure 1. Three methods of restoring Phyllospadix tested in this study. a) seedling attached to braided nylon line, b) 

sprig glued to the reef with marine epoxy, and c) plug woven through nylon net fastened to the reef by marine epoxy. 

b)

c)

a)
Final Study Report – Reed and Holbrook 

 62

Effort and efficacy of different methods of restoration 

I estimated the amount of effort (E) per unit transplant spent collecting, preparing and 

transplanting seedlings, sprigs and plugs for both intertidal and subtidal habitats. The effort (i.e., 

person hours) involved in the collection of seedlings was based on the time spent collecting 

reproductive shoots in the field, gathering and cleaning seeds dehisced in seawater aquaria, 

germinating seeds, and cultivating seedlings in laboratory cultures. Effort in preparing seedlings 

for outplanting consisted of the time spent in the laboratory attaching seedlings to nylon lines, 

while the effort in transplanting seedlings was based on the time spent attaching them to the reef 

(this included clearing the transplant plots on the reef of algae and debris). Estimates of effort for 

sprigs and plugs were based on the time spent collecting in the field, trimming leaves in 

preparation for transplantation, and transplanting units to adjacent areas on the reef. In the case of 

plugs, additional preparation time was spent cutting the netting used to secure the plugs and 

pulling the leaves of the plugs through it. The transport of transplant units, the set-up of 

laboratory cultures, and the mobilization and demobilization of gear and assistants were not 

included in any estimates of effort. 

The efficacy of the three different methods of restoration was evaluated by calculating the mean 

net change in the rhizome area of a transplant unit per unit effort measured in person hours. The 

mean net change in rhizome area (A) was calculated as: 

A = TS - (Dinitial — Dfinal), 

where T is the mean rhizome area (cm2) of the transplant unit six months after transplantation, S 

is the proportion of transplant units surviving six months, Dinitial is the mean area (cm2) of 

rhizome collected from the donor patch, and Dfinal is the mean net change in rhizome area (cm2) 

in the donor patch six months after donor collection. 

The mean net change in the rhizome area of a transplant unit per unit effort (CPUE) was 

calculated as: 

CPUE = A / E. 

Analyses 

Differences in survivorship between intertidal and subtidal habitats were tested individually for 

the different methods of restoration. A t-test using Satterthwaite’s approximation for the degrees 

of freedom (SAS v. 8.02) was used to test differences in survivorship between seedlings 

outplanted to the intertidal vs. the subtidal. Survivorship was estimated from twelve plots of 

eighteen seedlings. Two by two contingency tables were used to evaluate habitat specific 

differences in survivorship for sprigs and plugs. 

I tested the hypothesis that the rhizome area of transplanted sprigs and plugs changed 

significantly during the six month experiments using one-sample, two-tailed, t-tests, where the 

population mean μ was the area of rhizome at the beginning of the experiment. Similar analyses 

were done on the donor plots from which sprigs and plugs were harvested to assess whether any 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

 63

significant recovery of the donor plots bad occurred. Analyses testing the significance of rhizome 

growth in transplanted seedlings were not done because all seedlings lacked rhizomes at the start 

of the experiment and bad zero variance in rhizome area at the end of the experiment (the final 

rhizome area of seedlings was uniformly small and at the lower limit of my measurement 

capabilities). 

RESULTS 

Survivorship and leaf development 

Extreme differences in survivorship were observed among the different methods of restoration 

(Table 1). Very few of the 432 seedlings outplanted on nylon lines were alive after six months. 

Survivorship was equally poor at both the intertidal and subtidal sites (t16 = 0.98, P = 0.34 1). The 

use of epoxy and nylon line and the transport of seedlings to the field did not contribute 

substantially to low survivorship in the field; seedlings treated the same way but maintained in 

the laboratory showed 95% survivorship after two months (Appendix IV). The causes of high 

mortality in seedlings appeared to differ between the two habitats. The majority of seedlings at 

the intertidal site appeared to die in place. These seedlings lacked leaves after six months, but 

remained attached to the nylon line by the exocarp of the fruit. In contrast, poor survivorship at 

the subtidal site reflected high rates of dislodgement as most seedlings were completely missing 

from the outplanted nylon line at the end of the six-month study. 

Table 1. Survivorship of transplanted surfgrass after six months for the three methods of restoration in intertidal and 

subtidal habitats. Data for seedlings are means ± 1 SE. 

Method Number transplanted Survivorship (%)

Intertidal 

 Seedling 12 plots of 18 seedlings 2.3 ± 1.3 

 

 Sprig 42 47.6 

 Plug (small) 6 100 

 (medium) 6 100 

 (large) 6 16.7 

Subtidal 

 Seedling 12 plots of 18 seedlings 0.9 ± 0.6 

 

 Sprig 42 71.4 

 Plug (small) 6 100 

 (medium) 6 100 

 (large) 6 100 
Final Study Report – Reed and Holbrook 

 64

Survivorship of sprigs and plugs was substantially greater than that of seedlings (Table 1). Sprigs 

fared significantly better in the subtidal than the intertidal (71.4 % vs. 47.6 %; χ

2

1DF = 11.81, P = 

<0.001), where desiccation appeared to be a major cause of death. No sprigs transplanted to 

either site died as a result of becoming dislodged. Instead, evidence of death in sprigs was based 

on necrosis and loss of leaves. Plugs had the greatest survivorship as nearly all were alive after 

six months, with the exception of large plugs transplanted to the intertidal (where only one of six 

transplants survived). The five large plugs that died became dislodged within days after 

transplanting and quickly disappeared. 

The production of new leaves by transplant units that survived the six-month experiments was 

affected by both the site to which they were transplanted and the method of restoration. On 

average, seedlings, sprigs, and plugs transplanted to the subtidal produced more than three times 

as many new leaves as those transplanted to the intertidal (Figure 2a, F1,79 = 12.93, P <0.00 1). 

Differences in leaf production among restoration methods were equally large (Figure 2b, F4,79 = 

12.93, P <0.001). The few seedlings that survived grew remarkably well and showed nearly a 300 

% increase in the number of leaves after six months. Substantial leaf production also occurred in 

transplanted sprigs and small plugs, but was somewhat less than that of seedlings. In contrast, 

medium and large sized plugs grew poorly and actually lost leaves over the course of the 

experiment. Differences in leaf production among the different restoration methods were 

generally similar at the intertidal and subtidal sites (F4,79 1.47, P = 0.221 for the site x method 

interaction). 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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Figure 2. The effects of a) site and b) restoration method on the percentage change in the number of leaves of 

surviving transplants. Percentage change was calculated as [(final number of leaves - initial number of leaves) / 

initial number of leaves) * 100]. Data are means ± 1 SE. Means sharing the same letter are not significantly different 

from each other based on Ryan-Einot-Gabriel-Welch multiple range test (SAS v. 8.02). 

Rhizome growth and donor recovery 

Rhizome growth, which was used to estimate changes in the amount of surfgrass habitat, varied 

substantially among transplanted seedlings, sprigs and plugs that survived the six-month 

experiments (Table 2). Rhizomes of surviving sprigs consistently grew the most. The average 

rhizome area of sprigs transplanted to the intertidal increased by 42% while those transplanted to 

the subtidal increased by 86% Rhizome growth of the different-sized plugs varied inconsistently 

between the intertidal and subtidal sites. For example, significant rhizome growth was observed 

in small plugs transplanted to the intertidal, but not in small plugs transplanted to the subtidal 

(Table 2). Conversely, rhizome area increased significantly in medium plugs transplanted to the 

subtidal, but not in medium plugs transplanted to the intertidal. There was no significant change 

in the mean rhizome area of large plugs transplanted to the subtidal, whereas the rhizome area of 

the lone surviving large plug in the intertidal showed a slight increase (i.e. 9%). Rhizomes were 

typically poorly developed in six-month old seedlings. Nonetheless, the few outplanted seedlings 

that survived in the intertidal and subtidal had developed small rhizomes by the end of the 

experiment. 
Final Study Report – Reed and Holbrook 

 66

Table 2. Mean rhizome area (cm2) of the different transplant units at the end of the six month experiments. μ

represents the rhizome area (cm2

) of the transplant unit at the beginning the experiment. P is the probability that the 

mean is ≠ μ. * <0.05, ** <0.02, *** <0.001. NA indicates that data did not meet the assumptions for a t-test. 

Method Mean SE μ df t P

Intertidal 

 Seedling 0.5 0 0 NA NA NA 

 

 Sprig 7.1 0.9 5 18 2.452 * 

 Plug (small) 56.5 11.4 25 5 2.771 * 

 (medium) 86.8 18.4 100 5 -0.717 

 (large) 437 NA 400 0 NA NA 

Subtidal 

 Seedling 0.5 0 0 NA NA NA 

 Sprig 9.3 0.9 5 29 4.845 *** 

 Plug (small) 33.7 4.4 25 5 1.962 

 (medium) 146.2 12.1 100 5 3.807 ** 

 (large) 388.8 57.6 400 5 -0.194 

Striking differences were observed in the recovery of donor plots from which sprigs and plugs 

were harvested (Table 3). In the case of sprigs, full recovery was observed at both the intertidal 

and subtidal sites as the re-growth of cut rhizomes more than compensated for the loss of 

surfgrass incurred from harvesting. In sharp contrast, harvesting plugs led to significant losses of 

additional surfgrass because areas adjacent to donor plots sustained losses of surfgrass as well. 

These additional losses were observed within a few weeks of harvesting, and appeared to result 

from water motion that undermined the edges of cut rhizomous mats that were exposed when the 

plugs were removed. These subsequent losses of additional surfgrass were substantial, ranging 

from 67% to 533% of the initial donor area, and they were generally larger in the intertidal than 

in the subtidal. Large plugs taken from the intertidal had the largest mean net loss from 

harvesting. However, because of high variability among replicate donor plots, large plugs were 

the only type of donor plug whose subsequent losses of surfgrass were not significant (Table 3). 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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Table 3. Mean net change in rhizome area (cm2) of the donor plots from which the different transplant units were 

harvested six months after donor collection. μ represents the rhizome area (cm2

) of the donor plot at the beginning 

the experiment. P is the probability that the mean is ≠ μ. * <0.05, ** <0.02. NA indicates that a t-test was not 

applicable. Negative values indicate the area of bare space in the donor plot increased after donor collection. 

Method Mean SE μ df t P

Intertidal 

 Seedling 0 0 0 NA NA NA 

 

 Sprig 2.67 0.61 5 5 3.846 * 

 Plug (small) -70.1 33.23 25 5 -2.861 * 

 (medium) -532.7 214.16 100 5 -2.954 * 

 (large) -1065.8 620.47 400 4 -2.362 0.08 

Subtidal 

 Seedling 0 0 0 NA NA NA 

 Sprig 2.92 1.04 5 6 2.011 0.1 

 Plug (small) -16.64 9.74 25 3 -4.274 * 

 (medium) -252.19 107.41 100 3 -3.279 * 

 (large) -670 205.82 400 2 -5.199 * 

Effort and efficacy of different methods of restoration 

Overall, restoration using seedlings and sprigs required less effort than restoration with plugs 

(Figure 3). Seedlings, which were reared in the laboratory and attached to strings prior to 

outplanting, required more effort for transplant preparation than for collecting or transplanting. In 

contrast, relatively little effort was allocated to transplant preparation for sprigs and plugs; most 

of the effort for sprigs and plugs involved collecting and transplanting. In general, less effort was 

needed to collect and transplant sprigs and plugs in the subtidal than in the intertidal. This 

occurred because material for transplanting was more readily available in the subtidal resulting in 

shorter collection times. Moreover, transplanting sprigs and plugs required more effort in the 

intertidal because of the increased difficulty of clearing sand and debris there. 
Final Study Report – Reed and Holbrook 

 68

Figure 3. The amount of effort allocated to collection, preparation and transplantation for the different methods of 

restoration for a) intertidal and b) subtidal sites. See text for details on the work entailed in each category of effort 

for the different restoration methods.

The change in area of surfgrass habitat per unit effort varied tremendously among the methods of 

restoration tested (Table 4). The use of sprigs proved to be the most effective method for 

restoring surfgrass to both the intertidal and subtidal sites (as determined by changes in rhizome 

area after six months per work hour). Change in rhizome area per unit of effort (CPUE) for sprigs 

in the subtidal was more than five times that in the intertidal (25.33 cm2 rhizome · work h-1

compared to 4.2 cm2 rhizome · work h-1). This was a result of greater increases in net rhizome 

area and smaller effort involved in transplanting at the subtidal site. Small changes in rhizome 

area per unit effort for seedlings with < 0.04 cm2 rhizome · work h-1 reflected the high mortality 

and small gains in rhizome area observed over a six-month period. Interestingly, change in 

rhizome area per unit effort of plugs was negative for all three sizes at both the intertidal and 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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subtidal sites (Range= -16.89 cm2 rhizome · work h-1 to -1392.82 cm2 rhizome · work h-1), 

suggesting that this method of restoring surfgrass should be avoided. The negative values for 

plugs resulted from the additional losses of surfgrass over time incurred from harvesting. Even if 

these losses were discounted, change in rhizome area per unit effort for medium and large plugs 

would be exceedingly low due to the limited (and in some cases negative) growth observed in 

transplanted plugs, coupled with the relatively large amount of effort required to transplant them. 

Table 4. Mean net change in rhizome area of surfgrass (A), effort involved in transplanting per unit transplant (E), 

and net change in rhizome area per unit effort (CPUE) for the different methods of restoration in intertidal and 

subtidal habitats. See text for details of how A, E, and CPUE were calculated. 

A E CPUE 

Method (cm2

) (h) (cm2 rhizome · work h-1)

Intertidal 

 Seedling 

1.0 * 

10-2 0.27 0.04 

 

 Sprig 1.05 0.25 4.2 

 Plug (small) -38.60 0.57 -67.72 

 (medium) -545.90 0.73 -747.81 

 (large) 

-

1392.82 1.00 -1392.82 

 

Subtidal 

 Seedling 

4.5 * 

10-3 0.25 0.02 

 

 Sprig 4.56 0.18 25.33 

 Plug (small) -7.94 0.47 -16.89 

 (medium) -205.99 0.58 -355.16 

 (large) -681.20 0.73 -933.15 

DISCUSSION 

In the past several decades numerous attempts to restore a variety of seagrass species have been 

made. Spatial scales have ranged from small, experimental plots to large areas that are hectares in 

extent, and a variety of planting techniques using different life stages (plugs, seeds, seedlings, 

and sprigs) have been utilized (Thorhaug 1986; Thom 1990). The success of these efforts has 

been highly variable. For example, Thorhaug (1986) reported that 75 of 165 attempts resulted in 

some degree of re-establishment of seagrass populations. Similarly, 11 of the 17 projects 

reviewed by Thom (1990) were considered successful, so far as during the period of study 

seagrass survived and grew in at least a portion of the restoration site. Not surprisingly, both the 
Final Study Report – Reed and Holbrook 

 70

life stage and the local environmental conditions (including the presence of species that consume 

seagrasses) at the restoration site affected outcome. In my study, both of these aspects (life stage 

and location) were explored with respect to developing restoration strategies for surfgrass, 

Phyllospadix torreyi. Unlike other seagrasses, surfgrass lives attached to hard substrates, so 

restoration strategies previously developed for seagrasses that inhabit soft bottom areas are not 

applicable. Few attempts have been made to restore surfgrass, and there have been no prior 

attempts to evaluate the efficacy of using different life stages (Holbrook et al. 2002). This 

motivated me to test the performance of several life stages along the habitat gradient (rocky 

intertidal into shallow subtidal) normally occupied by the species. 

Growth and survivorship differed greatly among transplanted seeds, sprigs and plugs of 

surfgrass. Interestingly, growth was often inversely related to survivorship. Plugs, which as a 

group survived the best, grew the least, with medium and large-sized plugs actually losing leaves 

and showing little change in rhizome area over the duration of the study. In contrast, seedlings 

survived poorly, but those that did survive grew extremely well, increasing their leaf number by 

nearly four fold in six months. Survivorship and leaf growth for transplanted sprigs were 

intermediate between seedlings and plugs, while rhizome growth in transplanted sprigs was quite 

substantial. Similarly, there were great differences in recovery of donor plots from which sprigs 

and plugs were harvested for use in transplants. Re-growth of rhizomes that were cut to obtain 

sprigs was rapid, and at the end of six months had more than compensated for the harvesting 

loss, while harvesting of plugs led to substantial additional loss of surfgrass from the donor site 

as the holes experienced additional disturbance. The patterns of growth and survival of outplants 

and of recovery of donor plots, combined with the amount of effort involved, suggested that the 

largest gain in cover of rhizomes per unit of effort occurred when sprigs were used. Moreover, 

sprigs suitable for transplanting required relatively little effort to prepare and were relatively 

abundant at the study sites (Appendix V) suggesting that a minimal collection of sprigs for 

transplanting will not have a large impact to the existing P. torreyi beds. Collectively these 

features rendered sprigs the most acceptable form for use in restoration. It should be noted that 

sprig transplants compared to natural undisturbed sprigs over the same time period had very 

similar rhizome growth in the intertidal, yet sprig transplant only grew 1/3 as much as 

undisturbed sprigs in the subtidal (Appendix III). 

Although the majority of attempts to restore seagrasses have involved the use of older life stages 

(Williams & Davis 1996), concerns about donor bed recovery and the fact that harvesting large 

numbers of early life stages (such as seeds) would have relatively little impact on donor 

populations have led to increased interest in the use of these stages for restoration (Balestri et al. 

1998; Holbrook et al. 1999). Like many other seagrass species, P. torreyi can produce large 

numbers of seeds (up to 10,000 per square meter of surfgrass bed during the annual flowering 

season (Williams 1995). Typically, few seeds develop into seedlings (Stewart 1989; Williams 

1995; Blanchette et al. 1999; Holbrook et al. 2000), and early survival of seedlings is poor 

(Blanchette et al. 1999; Holbrook et al. 2000). Studies of three seedling cohorts that recruited 

naturally to the intertidal at More Mesa Reef showed an exponential decline in survivorship 

similar to that which was observed in laboratory reared seedlings outplanted to the field 

(Appendix I). Several factors account for the low numbers of seedlings that become established 

in surfgrass populations. Many seeds are consumed by predators, either prior to their release from 

the spadix or afterwards (Holbrook et al. 2000). The turbulent physical conditions in the coastal 

habitats occupied by surfgrass result in losses of seedlings via dislodgment from their host plants 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

 

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or from abrasion by nearby plants (Blanchette et al. 1999). Burial by sand in the subtidal zone 

and desiccation in the intertidal zone are additional causes of mortality of young seedlings 

(Appendix I). 

Recently-developed techniques for harvesting seeds of P. torreyi, and for laboratory storage, 

germination and propagation (Reed et al. 1998), make it possible to consider use of seedlings of 

this species for restoration, but concern now is whether the survival bottlenecks in the early life 

history stages can be overcome as part of the restoration strategy. The use of nylon line as an 

attachment host attempted to minimize dislodgement, a key element in recruitment (Blanchette et 

al. 1999). In my technique nearly 70% of the initial mortality in the intertidal after the first few 

days was due to the inability to secure the nylon line to the reef (Appendix II). However, of the 

nylon lines still secured to the reef after six months, I found that many seedlings were still 

attached to the nylon line even after the shoots were gone. This suggests that the primary factor 

contributing to the low survivorship in the intertidal (if the nylon line remained attached to the 

reef) appeared to be desiccation. Placement of the seedlings in areas cleared of algae protected 

them from abrasion from neighboring plants, but probably increased the desiccating effects of 

exposure during low tides. Only 12% of the seedlings survived after exposure during just two 

tidal cycles. Compared to natural recruits in the intertidal (which attach directly to algae that can 

be used as cover from effects of exposure) outplanted seedling survivorship was approximately 

three times lower over the same time period (Appendix I). Desiccation was not a factor for 

subtidal seedlings, but these also experienced rapid mortality, with fewer than 50% surviving 

after just 10 days. Unlike seedlings outplanted intertidal, only 30% of the initial mortality 

observed in the subtidal was due to removal of the nylon line (Appendix II). This suggests that I 

had better success in securing the nylon line to the reef in the subtidal compared to the intertidal. 

Dislodgement of seedlings from the nylon line appeared to be the major cause of loss of subtidal 

seedlings. It is possible that drift algae could have hooked the unattached arm of the fruit. 

Additional research is needed to develop methods to prevent losses of outplanted seedlings from 

desiccation and dislodgement for this technique to be effective in restoration. 

The apparent sources of mortality of seedlings in my experiments contrast with results of several 

other studies that reported poor survival of transplanted seeds and seedlings of seagrasses due to 

consumption by crabs (Davis et al. 1998) and other consumers (Harwell & Orth 1999). An 

additional problem that I observed in my experiments was that after six months, outplanted 

seedlings had not formed adventitious roots [compared to naturally recruited seedlings which had 

rhizome growth over 4 cm (Appendix I)]. All surviving outplanted seedlings were still attached 

to the line at the end of the experiment. It may well be the case that the seedlings will have 

difficulty attaching to the rocky substrate and growing rhizomes while on the nylon line, but 

longer-term experiments would be required to determine this. 

Harvesting of plant material from natural, healthy beds can be a large concern for restoration 

managers. While this is less of a concern for faster-growing species such as Halodule wrightii 

and Syringodium filiforme, for slower-growing species such as Thalassia testudinum and P. 

torreyi it would be unwise to collect large plugs of material for restoration. My results indicate 

that the concerns are well justified, because not only did plugs grow poorly, collecting from 

surfgrass beds resulted in additional damage to the existing population. The cut material on the 

outer edges of the holes became eroded and was easily removed from the rocky substrate when 

water motion was high. This had the result that the holes grew even larger after the plugs were 
Final Study Report – Reed and Holbrook 

 72

removed. Even if the transplanted plugs had survived and grown well, the additional loss of 

surfgrass from the donor plot and the failure of any re-growth to occur in the donor areas after six 

months suggest that use of this life stage for restoration should be avoided. In addition, 

observations after eighteen months found that approximately only 55% of the area removed from 

donor plugs had recovered overall. 

P. torreyi occurs along a depth gradient, from the intertidal to the shallow subtidal zone. As such, 

it encounters a wide range of physical conditions, and knowledge of the tolerance of the species 

to factors such as light, sedimentation, temperature, and susceptibility to dislodgement from 

water motion provides insight into possible restoration strategies. Not surprisingly, the efficacy 

of the three restoration methods that I tried varied considerably between the intertidal and 

subtidal. In general, survivorship and growth of transplants and the recovery of donor plots all 

tended to be higher in the subtidal than in the intertidal, and the effort expended in transplanting 

was also less in the subtidal. That all three methods of restoration varied consistently in this 

regard suggests that while restoration success in surfgrass is likely to vary along a depth gradient, 

it probably will not require that different techniques be used in different depths. 

CONCLUSION 

This research suggests successful restoration to increase vegetative growth of P. torreyi habitat is 

highly dependent on type of technique. Through evaluation of several potential restoration 

techniques, I found that transplanting of sprigs provided the highest net change in surfgrass 

habitat per unit effort. The outcome was affected by several factors that contributed to the overall 

change in habitat. Favorable growth and survival were significant elements, however, further 

investigation on cost-effectiveness and recovery of donor plots from which the sprigs and plugs 

were collected played important roles in evaluation of overall success. Furthermore, site selection 

along the gradient of surfgrass habitat also affected outcome with subtidal transplants 

outperforming intertidal transplants for the same technique. Additional tests need to be 

conducted to identify ways to increase survivorship of transplants due to physically harsh 

intertidal habitats and to assess long-term costs to host beds from intensive collections. Although 

I found results to be pertinent to my study sites, further experimentation is needed to evaluate 

performance under variable geographical locations. 
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to eelgrass transplants. Restoration Ecology 6: 297-302. 

Dawes, C.J., J. Andorfer, C. Rose, C. Uranowski, and N. Ehringer. 1997. Regrowth of the 

seagrass Thalassia testudinum into propeller scars. Aquatic Botany 59:138-155.

den Hartog, C. 1970. The Sea-grasses of the World. North-Holland, Amsterdam, The 

Netherlands. 276 pp. 

Edgar, G. 1990. The influence of plant structure on the species richness, biomass and secondary 

production of macrofaunal assemblages associated with Western Australia seagrass beds. 

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Fonseca, M.S., W.J. Kenworthy, D.R. Colby, K.A. Rittmaster, and G.W. Thayer. 1990. 

Comparisons of fauna among natural and transplanted eelgrass Zostera marina meadows: 

criteria for mitigation. Marine Ecology Progress Series 65: 251-264. 
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Fonseca, M.S., W.J. Kenworthy, F.X. Courtney, and M.O. Hall. 1994. Seagrass planting in the 

Southeastern United States: methods for accelerating habitat development. Restoration 

Ecology 2: 198-212. 

Fuss, C.H., and J.A. Kelly. 1969. Survival and growth of sea grasses transplanted under artificial 

conditions. Bulletin of Marine Science. 19(2): 351-365. 

Harlin, M.M. 1975. Epiphyte-host relations in seagrass communities. Aquatic Botany 1: 125-131. 

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experiments and implications for large-scale restoration. Aquatic Botany 64: 51-61.

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structures by establishing surfgrass (Phyllospadix torreyi). Pages 582-589 in Proceedings 

Seventh International Conference on Artificial Reefs, San Remo, Italy. 

Holbrook, S.J., D.C. Reed, K. Hansen, and C.A. Blanchette. 2000. Spatial and temporal patterns 

of predation on seeds of surfgrass Phyllospadix torreyi. Marine Biology 136: 739-747. 

Holbrook, S.J., D.C. Reed, and J.S. Bull. 2002. Survival experiments with outplanted seedlings 

of surfgrass (Phyllospadix torreyi) to enhance establishment on artificial structures. ICES 

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Kelly, J.A., C.M. Fuss, and J.R. Hall. 1971. The transplanting and survival of turtlegrass, 

Thalassia testudinum, in Boca Ciega Bay, Fla. Fisheries Bulletin 69: 273-280. 

Larkum, A.W.D., A.J. McComb, and S.A. Shepherd. 1989. Biology of seagrasses: a treatise on 

the biology of seagrasses with special reference to the Australian region. New York, 

Elsevier. 

McLusky, D.S., D.M. Bryant, and M. Elliot. 1992. The impact of land-claim on macrobenthos, 

fish and shorebirds on the Forth Estuary, eastern Scotland. Aquatic Conservation: Marine 

and Freshwater Ecosystems. 2(3): 211-222. 

Morand, P., and X. Briand. 1996. Excessive growth of macroalgae: a symptom of environmental 

disturbance. Botanica Marina 39: 491-516. 

Orth, R.J., M.C. Harwell, and J.R. Fishman. 1999. A rapid and simple method for transplanting 

eelgrass using single, unanchored shoots. Aquatic Botany 64: 77-85.

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Moore, J.M. Rhode, and H.E. Woods. 2000. A review of issues in seagrass seed 

dormancy and germination: implications for conservation and restoration. Marine 

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Paling, E.I., M. van Keulen, K.D. Wheeler, J. Phillips, R. Dyhrberg, and D.A. Lord. 2001. 

Improving mechanical seagrass transplantation. Ecological Engineering 18: 107-113. 

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Phillips, R.C. 1979. Ecological Notes on Phyllospadix (Potamogetonaceae) in the northeast 

Pacific. Aquatic Botany 6: 159-170. 

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Aquatic Botany 62: 71-80.

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Carolina, USA. 

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158. 

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APPENDIX I 

GROWTH AND SURVIVORSHIP OF NATURALLY RECRUITED SURFGRASS 

(PHYLLOSPADIX TORREYI) SEEDLINGS AT A ROCKY INTERTIDAL REEF 

METHODS 

I followed the survivorship and growth of naturally occurring surfgrass seedlings (Phyllospadix 

torreyi) to obtain a baseline for comparison to experimentally outplanted seedlings and 

investigate recovery following natural disturbance. The study was conducted at More Mesa Reef 

(see Chapter 1 for site description). Field surveys of the P. torreyi population at this site were 

conducted from 1994 to 2001 as part of a larger study to gather baseline data on the natural 

distribution of P. torreyi and algae. One 25 m long transect was established running parallel to 

the coastline at about -0.07 feet mean low water level. The area was sampled using a point 

contact method each summer and winter to assess P. torreyi percent cover. Surveys in winter 

1994 indicated that the area within the study area was densely covered in P. torreyi with up to 

71.4% covered by leaves (Reed and Holbrook, unpublished data). However, high sand flux from 

December 1995 to June 1999, which entirely buried P. torreyi and algae in sand, potentially led 

to the mortality of all existing P. torreyi in the study area. This was the basis for my census to 

investigate natural recovery of P. torreyi in the absence of sand in the following years. 

A 25 m long x 12 m wide area was selected within the survey area and stainless steel eyebolts 

(5/16” X 3”) were screwed into the substrate at each of the four corners. Naturally recruited P. 

torreyi seedlings were mapped within the designated area. Distances were then taken from each 

seedling to at least two permanent bolts in order to relocate the seedling at later (census) dates. 

Survivorship and growth of three cohorts of seedlings recruited to the study area were followed 

from December 1998 to June 2001. The first census in December 1998 found 30 naturally 

recruited seedlings in the vicinity of the experimental area (98-99 cohort). The young seedlings at 

this time had between 11 to 58 leaves (mean 29.5 +/- 4.1) and were assumed to be of the same 

cohort, recruited within that year. Unfortunately, seedlings within this cohort became entirely 

buried in sand soon after census. Mean depth of sand covering the seedlings was measured and 

persisted for 162 days (Figure 1). Subsequently the sand never returned. The second census 

mapped 148 total new naturally recruited seedlings one year later in January 2000 (99-00 cohort) 

with <5 leaves per seedling. The most recent census found a total of 194 new P. torreyi seedling 

recruits to the study area in December 2000 (00-01 cohort) and had on average 3.06 +/- 0.2 

leaves per seedling. Based on my laboratory observations of seedling growth I assumed seedlings 

for each of the last two censuses were all from the same cohort and were no more than onemonth post germination. 
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Figure 1. Average depth of sand covering 1998-1999 seedling cohort at More Mesa from December 1998 to 

December 2000. 

Data on individual seedling survivorship and growth for each of the three cohorts were collected 

periodically through June 2001. Survivorship was recorded by presence or absence of each 

seedling at each census date. Seedlings were considered dead if no leaves were present over two 

consecutive sample periods or if the seedling was missing. Growth of surviving P. torreyi 

seedlings was measured by mean leaf length, longest leaf length, the number of leaves per 

seedling, and mean rhizome length. 

RESULTS 

Survivorship for naturally occurring seedlings in the 98-99 cohort showed dramatic reduction in 

survivorship with only 40% remaining after the first 70 days (Figure 2a). However, after nearly 

220 days, survivorship leveled off at 8% at the end of the study. A similar initial reduction in 

survivorship was observed for the 99-00 and 00-01 cohorts with approximately 40% survivorship 

after 100 and 75 days of the initial survey, respectively (Figure 2b, 2c). Survivorship also tapered 

off with 18% remaining at the end of the study after 550 days for the 99-00 cohort and 25% after 

nearly 200 days for the 00-01 cohort. Mortality of seedlings is potentially due to dislodgement or 

desiccation. Seedlings observed to have the majority of their leaves brown and dry did not 

survive the subsequent census. Naturally occurring seedling recruits that survived typically were 

firmly attached to the base of the stipe of the host algae. This allowed the fruit to stay moist and 

covered from harmful sunlight during extreme low tides. 
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Figure 2. Percent survivorship of natural P. torreyi seedling recruits on host algae for a) 98-99 cohort, b) 99-00 

cohort, and b) 00-01 cohort at More Mesa Reef study site. 

Surviving seedlings grew rhizomes at an exponential rate. The mean rhizome length of all 

cohorts at first census was <0.5 cm yet after 400 days, mean rhizome length of the 98-99 cohort 

was approximately 12 cm and grew to over 40 centimeters after nearly 800 days. The mean 

rhizome length of the 99-00 cohort quadruped after 400 days (Figure 3b). Likewise, rhizome 

length doubled after 200 days for the 00-01 cohort (Figure 3c). Although only rhizome length 

was measured, width also increased dramatically as the rhizome bifurcated rapidly. Mean number 

of leaves per seedling also grew substantially over time at an exponential rate (Figure 4). 

Surprisingly, the one surviving seedling had over 1000 leaves after 800 days (Figure 4a). Mean 
Final Study Report – Reed and Holbrook 

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leaf length and longest leaf length were similar between cohorts (Figure 5 and Figure 6). Growth 

was linear over time yet varied through censuses with seasonal declines during the fall and winter 

when low tides occur in the afternoon. Rhizome length had significant linear correlation with 

number of leaves (p <0.0001) for all cohorts (Figure 7). 

 

Figure 3. Mean rhizome length of natural P. torreyi seedling recruits (+/- SE) on host algae for a) 98-99 cohort, b) 

99-00 cohort, and b) 00-01 cohort at More Mesa Reef study site. 
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Figure 4. Mean number of leaves (+/- SE) on natural P. torreyi seedling recruits on host algae for a) 98-99 cohort, 

b) 99-00 cohort, and b) 00-01 cohort at More Mesa Reef study site. 
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Figure 5. Mean length of leaves on natural P. torreyi seedling recruits (+/- SE) on host algae for a) 98-99 cohort, b) 

99-00 cohort, and b) 00-01 cohort at More Mesa Reef study site. 
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Figure 6. Mean longest leaf length on natural P. torreyi seedling recruits (+/- SE) on host algae for a) 98-99 cohort, 

b) 99-00 cohort, and b) 00-01 cohort at More Mesa Reef study site. 
Final Study Report – Reed and Holbrook 

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Figure 7. Rhizome length vs. number of leaves for natural P. torreyi seedling recruits on host algae for a) 98-99 

cohort, b) 99-00 cohort, and b) 00-01 cohort at More Mesa Reef study site.
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APPENDIX II 

GROWTH AND SURVIVORSHIP OF SURFGRASS (PHYLLOSPADIX TORREYI)

SEEDLINGS OUTPLANTED ON EPOXY BEADS 

METHODS 

I tested direct attachment of surfgrass seedlings (Phyllospadix torreyi) set in epoxy in the 

laboratory and transplanted to the field to evaluate this method as a viable technique for 

restoration. This experiment coincided with that involving seedlings outplanted on nylon lines 

(see Chapter 1). Here I attempted to minimize seedling dislodgement in the field by embedding 

seedlings in marine epoxy prior to outplant. Seedlings were collected in the field and reared in 

the laboratory as described in Chapter 1. Viable seedlings were selected and embedded in a small 

“bead” of marine epoxy (1 cm in diameter) in the laboratory using fine forceps such that the 

emergent leaves from the seedling were not covered by the epoxy. A small “bead” was formed 

around the exocarp of the fruit which held it to the epoxy (Figure 1). The epoxy and seedling unit 

is referred to as a seedling bead. Seedling beads were then placed in a flow through seawater tank 

to keep the water clean while the epoxy hardened. Once dry, the seedling beads were stored in 

the laboratory under the same conditions as the seedlings on nylon line described in Chapter 1 

before outplant. In November 2000, seedling beads were outplanted to 30 cm x 30 cm 

experimental plots at intertidal and subtidal study sites (More Mesa Reef and Mohawk Reef, 

respectively; see Chapter 1 for site descriptions). Seedling beads were fastened to the reef using 

small amounts of Z-Spar A788 marine epoxy putty. Efforts were taken to ensure that the shoots 

of seedlings were upright. Eighteen seedlings were outplanted in a uniform grid to each of 12 

experimental plots at each of the two sites adjacent to healthy stands of surfgrass. Branches from 

surrounding algae were clipped to inhibit dislodgement of seedlings by whipping. 

Figure 1. Seedlings are firmly attached in the laboratory to the artificial substrate host “beads” made of marine 

epoxy prior to outplant. 
Final Study Report – Reed and Holbrook 

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The efficacy of this method of restoration was evaluated using data collected on survivorship and 

growth of the seedling outplants after six months. Mortality of seedlings occurred either by 1) the 

inability to secure the seedling bead to the reef, 2) seedling death in place (loss of leaves with 

fruit still attached) or 3) dislodgment of the seedling directly from the bead. Survivorship of 

seedling beads at More Mesa and Mohawk was followed for over 200 days. To assess early 

sources of mortality, outplanted seedlings were surveyed after 13 days for subtidal outplants and 

8 days for intertidal outplants. Data from the seedlings outplanted on nylon lines are included for 

comparison (see Chapter 1 for methods). Data collected, however, did not distinguish between 

seedlings that had died in place or were removed directly from the bead. The growth of surviving 

outplanted seedlings was evaluated by leaf counts per surviving seedling and calculating mean 

leaf length from measurements. Potential causes for mortality were evaluated after the first 

census date. I noted if the seedling was either dislodged (from the bead or dead in place) or if the 

z-spar failed to secure the seedling bead to the reef. 

RESULTS 

For both the More Mesa and Mohawk seedling bead outplants, a sharp decline in survivorship 

was seen after the first 90 days (Figure 2). After two hundred days very few seedlings remained 

regardless of the site. As time progressed, mortality decreased suggesting that the seedlings’ 

survivorship would eventually level off at some point yet overall survivorship for this technique 

was poor. 

Figure 2. Percent surviving (+/- SE) of outplanted seedlings on epoxy beads to More Mesa Reef (hatched) and 

Mohawk Reef (solid line) study sites. Data are shown for 12 groups of 18 seedlings. 

The primary cause of mortality of seedlings was different depending on type of technique and 

location outplanted (Figure 3). A greater percentage of seedlings died in place or were removed 

directly from the bead outplants at More Mesa Reef. However, seedlings outplanted on nylon line 

had higher mortality at More Mesa due to the inability to secure the line to the reef. Seedlings 

outplanted on beads were more susceptible to desiccation which dried seedlings in place at More 
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Mesa and resulted in a higher mortality. Nylon lines had more drag and potentially were more 

easily removed during periods of high water flow. In addition, individual seedlings on nylon lines 

outplanted to Mohawk Reef could be more susceptible to removal by drift algae or whipping of 

unclipped adjacent algae that hooked the second barb of the fruit and broke the seed from the 

bead or nylon line. 

Figure 3. Initial sources of mortality in seedling outplant experiments. Sources of mortality of outplanted seedlings 

were either by the inability of the seedling bead or nylon line to secure to the reef or the seedling dying in place or 

being dislodged from the bead or nylon line. 

Growth of seedlings based on new leaves and mean leaf length was dependent on site outplanted. 

After 200 days, seedlings outplanted to the subtidal site at Mohawk Reef on average developed 

slightly more leaves and were approximately 10 cm longer than seedlings outplanted to the 

intertidal site at More Mesa (Figure 4 and Figure 5). It should be noted that mean values for 

seedlings in the later portion of the experiment were calculated from very low numbers (1 

seedling and 3 seedlings for Mohawk and More Mesa, respectively). 
Final Study Report – Reed and Holbrook 

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Figure 4. Mean development of leaves (+/- SE) of outplanted seedlings on epoxy beads to More Mesa Reef 

(hatched) and Mohawk Reef (solid line) study sites. 

Figure 5. Mean leaf length (+/- SE) of outplanted seedlings on epoxy beads to More Mesa Reef (hatched) and 

Mohawk Reef (solid line) study sites. 
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APPENDIX III 

GROWTH COMPARISON OF TRANSPLANTED AND UNDISTURBED SURFGRASS 

(PHYLLOSPADIX TORREYI) RHIZOME SPRIGS 

METHODS 

To estimate natural growth of undisturbed Phyllospadix torreyi rhizomes and associated leaves 

and compare growth to transplanted sprigs in Chapter 1, I marked undisturbed rhizomes and 

monitored growth for approximately six months. Experiments were initiated in both summer and 

winter for seasonal comparisons. For summer experiments, undisturbed rhizome sprigs (N=11), 

were mapped in May 2000 at More Mesa Reef (Chapter 1 for site description) which coincided 

with the harvest and transplantation of sprigs (N=20) from established beds to adjacent areas 

lacking surfgrass. The experiment was also replicated in the subtidal study site at Mohawk Reef 

(see Chapter 1 for site description) in June 2000 with 15 and 30 replicates for undisturbed and 

transplanted sprigs, respectively. Transplanted sprigs were harvested and secured to the reef as 

described in Chapter 1. A reference marker was glued to the reef next to each undisturbed and 

transplanted sprig to aid in relocating them for purposes of measuring growth. Mean increase in 

rhizome area was estimated as the length of new rhizome (measured to nearest 1⁄2 cm) that had 

grown from the end of the undisturbed rhizome sprig or transplant, multiplied by the rhizome 

width (typically 1 cm). Only leaves associated with new growth of the rhizome were counted. 

The experiments were followed for approximately six months. 

To evaluate variation in rhizome and leaf growth between seasons and compare rhizome growth 

of transplanted rhizome sprigs conducted in Chapter 1, the experiment was repeated in 

November 2000. Undisturbed rhizome sprigs were marked at More Mesa Reef and Mohawk 

Reef (N=21 and 10, respectively) and sprigs were transplanted to adjacent areas (N=42 for both 

sites). Increase in rhizome area and leaves associated with rhizome growth were followed for 

approximately six months. 

RESULTS 

Differences in rhizome growth of undisturbed and transplanted sprigs varied inconsistently 

between sites and seasons. Summer More Mesa sprigs (Figure lb) and winter Mohawk sprigs 

(Figure 1c) had virtually no difference in rhizome growth. However, winter More Mesa (Figure 

la) and summer Mohawk (Figure 1d) undisturbed rhizome sprigs had approximately 3 cm2 

greater area after approximately 175 days. The highest growth occurred for both undisturbed and 

transplanted sprigs at Mohawk Reef during the summer season study. 
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Figure 1. New rhizome area for transplant and undisturbed rhizome sprigs during a) winter More Mesa study sprigs 

(mean +/- 1 SE, N = 42 and 21 for each treatment, respectively), b) summer More Mesa study sprigs (mean +/- 1 

SE, N = 20 and 11 for each treatment, respectively), c) winter Mohawk study sprigs (mean +/- 1 SE, N = 42 and 10 

for each treatment, respectively) d) summer Mohawk study sprigs (mean +/- 1 SE, N = 30 and 15 for each treatment, 

respectively). Hatched line is data for undisturbed rhizome sprigs, and solid line is data for transplanted rhizome 

sprigs.

Mean new number of leaves associated with new rhizome growth was similar across transplants 

and undisturbed sprigs regardless of season (Figure 2). The highest growth of new leaves 

occurred for summer More Mesa sprigs with approximately 50 new leaves for both transplant 

and undisturbed rhizomes after 200 days (Figure 2b). Winter Mohawk sprigs developed fewest 

leaves with only approximately 20 leaves after 150 days (Figure 2c). 

. 
 An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration 

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Figure 2. Mean increase in number of leaves for transplant and undisturbed rhizomes for a) winter More Mesa study 

sprigs (mean +/- 1 SE, b) summer More Mesa study sprigs (mean +/- 1 SE), c) winter Mohawk study sprigs (mean 

+/- 1 SE), d) summer Mohawk study sprigs (mean +/- 1 SE). Hatched line is data for undisturbed rhizome sprigs, 

and solid line is data for transplanted rhizome sprigs. 
Final Study Report – Reed and Holbrook 

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APPENDIX IV 

SURVIVORSHIP OF SURFGRASS (PHYLLOSPADIX TORREYI) SEEDLING 

LABORATORY CONTROLS 

METHODS 

To evaluate the effect of nylon line or epoxy on the early survivorship of Phyllospadix torreyi 

seedlings, seedling controls were grown in the laboratory. The experiment investigated the 

consequences of using material to attach seedlings to the reef and stresses from transport of 

outplant units in the field, Treatment controls consisted of (l) loose seedlings with no material, 

(2) loose seedlings with an equal number of loose epoxy beads, approximately 1 cm in diameter 

(3) loose seedlings with an equal number of 5 cm lengths of loose nylon line, (4) seedlings 

attached to 5 cm lengths of nylon line (see Chapter 1 for description), (5) seedlings embedded in 

epoxy beads (see Appendix III for description), (6) seedlings attached to nylon line brought to 

Mohawk Reef under similar transport stress as outplants and returned to laboratory culture, (7) 

seedlings attached to epoxy beads brought to Mohawk Reef under similar transport stress as 

outplants and returned to laboratory culture, (8) seedlings attached to epoxy beads brought to 

More Mesa Reef under similar transport stress as outplants and returned to laboratory culture, 

and (9) seedlings on nylon line brought to More Mesa Reef under similar transport stress as 

outplants and returned to laboratory culture. Seedlings were collected in the field and reared in 

the laboratory as described in Chapter 1. Six replicate groups of 20 seedlings per treatment were 

placed in culture dishes with 50 ml of sterile filtered seawater (0.2μm) enriched with 50ul 

nutrient stock solution (Provosoli 1968) for each of the nine controls. The culture dishes were 

maintained at 15°C at an irradiance of 40-50 μE m-2 

s

-1 using a 14:10 h L:D photoperiod under 

mild agitation. All seedlings were rinsed with dionized water and the culture media were changed 

on a weekly basis. Seedling survivorship was assessed after two months. 

RESULTS 

Seedling survivorship was relatively high for all laboratory control treatments after a two-month 

period (Table 1). Most treatments had over 95% survivorship with no direct correlation to a 

particular material. In addition, a certain percentage can be expected to not survive even under 

optimal growing conditions. These data demonstrate that the use of nylon line or epoxy used to 

attach the seedlings to the reef as a potential restoration technique has no negative effects on 

early seedling mortality. 
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Table 1. Two-month percent survivorship of laboratory controls. Data are 20 seedlings per treatment (n=6 replicates 

per treatment). 

Treatment Survivorship

 

Loose seedlings 93.33% 

Loose seedlings with epoxy bead 99.17% 

Loose seedlings with nylon line 98.33% 

Seedlings attached to nylon line 95.83% 

Seedlings embedded in epoxy 95.83% 

Transported seedlings attached to nylon line to subtidal 95.00% 

Transported seedlings embedded in epoxy to subtidal 93.33% 

 

Transported seedlings embedded in epoxy to intertidal 90.83% 

Transported seedlings attached to nylon line to intertidal 98.33% 
Final Study Report – Reed and Holbrook 

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APPENDIX V 

THE AVAILABILITY OF SURFGRASS (PHYLLOSPADIX TORREYI) SPRIGS FOR 

TRANSPLANTING IN AN INTERTIDAL AND SUBTIDAL ROCKY REEF 

METHODS 

To assess the availability of Phyllospadix torreyi rhizome tips for use as sprigs for restoration, I 

conducted surveys of the density of rhizome sprigs in intertidal and subtidal habitats in March 

2001. At Mohawk Reef and More Mesa Reef (subtidal and intertidal habitats, respectively, see 

Chapter 1 for site descriptions), I placed a meter ruler haphazardly next to the edge of the 

existing P. torreyi bed and counted the number of sprigs within 10 cm of the meter rule. Fortysix 1 m x 10 cm areas were sampled along approximately two hundred meters parallel to the 

shore at Mohawk Reef and eighteen 1 m x 10 cm areas were sampled along approximately one 

hundred meters at More Mesa Reef. The sample areas at each site were not contiguous and most 

were greater than 10 meters apart. 

RESULTS 

I found that Mohawk Reef had slightly more sprigs than More Mesa, with an average of 10.1 +/- 

0.5 sprigs per linear meter compared to 8.1 +/- 1.2, respectively. 
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APPENDIX VI 

LEAF AND RHIZOME BIOMASS OF SURFGRASS (PHYLLOSPADIX TORREYI)

RHIZOME SPRIGS USED IN RESTORATION EXPERIMENTS 

METHODS 

To provide a means to assess biomass production of P. torreyi sprigs transplants, I harvested 

sprig rhizomes (>5cm) and the attached leaf material for analysis in April 2001. This study 

interprets restoration growth measured by rhizome primary cover and new number of leaf counts 

in Chapter 1, in terms of biomass production per 1 cm2 rhizome and biomass production for 1 cm 

leaf lengths. Sprigs were harvested from established subtidal beds at Mohawk Reef (see Chapter 

1 for site description) by removing an unbranched tip from an actively growing rhizome with a 

sharp knife without damaging the root hairs. Nineteen samples were collected in the field and 

brought to the laboratory. Each harvested sprig was cut in the laboratory to exactly 5 cm 

measured from the cut end to the base of the emerging shoots at the apical end of the rhizome. 

The width of each rhizome sprig was 1 cm for all harvested sprigs. Data recorded for each 5 cm 

sprig included number of leaves, longest leaf length (in centimeters), and estimated average leaf 

length (in centimeters). Leaves were then cut from the base of the rhizome and wet weights (in 

grams) were recorded for the rhizome sprigs and the leaves. Mean biomass of a 1 cm2 rhizome 

sprig was calculated by: 

Wet weight of rhizome/ (total rhizome length x width). 

The mean biomass of a 1 cm leaf length was calculated by: 

Wet weight of leaves/ (total # leaves x average leaf length). 

RESULTS 

I found that a 5 cm long unbranched sprig in the field had on average 16.95 +/- 0.86 leaves with 

an average leaf length of 29.42 +/- 1.50 cm with the longest being 47.90 +/- 2.79 cm. Mean wet 

weights of leaves were found to be 3.48 +/- 0.24 grams, and wet weights of rhizomes were 

slightly greater at 3.87 +/- 0.13 grams. Biomass of a 1 cm2 rhizome sprig and a 1 cm long leaf 

was calculated to be 0.774 +/- .025 and 0.0072 +/- .0004 grams, respectively. 
Final Study Report – Reed and Holbrook 

 96

ACKNOWLEDGEMENTS 

I would like to dedicate this thesis to Mike Anghera, who as a mentor provided the guidance and 

encouragement to get where I am today. For me and for many others, you are most deserving of 

recognition for your capability and solid work ethic in everything you do. Mike, I will never 

forget our long days on the boat, nights in the intertidal, and all the hard work and good times 

side by side in the Reed Lab. Your friendship will always be cherished. 

A sincere thank you to Dan and Sally who gave me the opportunity and freedom to pursue this 

exciting research. Their tireless hard work and thorough, intellectual direction throughout the 

long process of drafts led to the completion of this thesis. To Scott H, who provided enthusiastic 

comments, I hope to meet up again out in the surf. 

To Shane, Terry, and Dave, you guys were always there to lend a helping hand or offer much 

needed advice, and to Bonnie for always coming through in the end. 

To all the field, lab and diving volunteers and general support team, Mike Almer, Carrie Baer, 

Ian Blake, Bryn Evans, Maria Fontes, Chris Faist, Rachel Fogelman, Jennifer Heizer, Rochelle 

King, Patric Larush, Stu Levenbach, Jessica VanLeuven, Julie Love, Mike Mazur, Mike Muzzio, 

Brent Maridian, Steph Mutz, Wendy Manard, Seth Reder, Ben Reder, Reed Sante, Garrett 

Snyder, Reed Sante, Allan Willis and Brian Zamacona, I hope you all learned something from 

this project while having fun at the same time. And very special thanks to my dedicated crew, 

Jobnathan Blythe, Charlie Boch, Jake Bunch, Lauren Deeb, Maria Fuchs, Carey Gaist, Andy 

Quinn, Holly Rodrigues, Ashleigh Rossman, and Mark Brinkman, for going way beyond. This 

research would not have been possible without all of your support, hard work and dedication. 

Many of you started as field assistants and became close friends. You guys are the best and have 

made this experience the greatest it could be. 

To the Interns from Heaven, Katie and Ellen, whose fantastic enthusiasm and crazy humor made 

the entire summer field season though nighttime tides most enjoyable. 

Special thanks to Elise Stephens, whose motivation, support and patience carried me through the 

days of anxiety, frustration, exhaustion and accomplishment. 

To my family, who has encouraged me throughout my entire career as a student, your 

unconditional love and unwavering support is immeasurable. 

This research was generously supported in part by the Minerals Management Service and the 

Coastal Toxicology Component of the University of California Toxic Substances Research and 

Teaching Program. 
An experimental evaluation of methods of surfgrass (Phyllospadix torreyi) restoration

 97

The Department of the Interior Mission 

As the Nation's principal conservation agency, the Department of the Interior has responsibility for most 

of our nationally owned public lands and natural resources. This includes fostering sound use of our 

land and water resources; protecting our fish, wildlife, and biological diversity; preserving the 

environmental and cultural values of our national parks and historical places; and providing for the 

enjoyment of life through outdoor recreation. The Department assesses our energy and mineral 

resources and works to ensure that their development is in the best interests of all our people by 

encouraging stewardship and citizen participation in their care. The Department also has a major 

responsibility for American Indian reservation communities and for people who live in island territories 

under U.S. administration. 

The Minerals Management Service Mission 

As a bureau of the Department of the Interior, the Minerals Management Service's (MMS) primary 

responsibilities are to manage the mineral resources located on the Nation's Outer Continental Shelf 

(OCS), collect revenue from the Federal OCS and onshore Federal and Indian lands, and distribute 

those revenues. 

Moreover, in working to meet its responsibilities, the Offshore Minerals Management Program

administers the OCS competitive leasing program and oversees the safe and environmentally sound 

exploration and production of our Nation's offshore natural gas, oil and other mineral resources. The 

MMS Royalty Management Program meets its responsibilities by ensuring the efficient, timely and 

accurate collection and disbursement of revenue from mineral leasing and production due to Indian 

tribes and allottees, States and the U.S. Treasury. 

The MMS strives to fulfill its responsibilities through the general guiding principles of: (1) being 

responsive to the public's concerns and interests by maintaining a dialogue with all potentially affected 

parties and (2) carrying out its programs with an emphasis on working to enhance the quality of life for 

all Americans by lending MMS assistance and expertise to economic development and environmental 

protection.