Largescale Salvage of Coastal Sage Scrub through Transplantation

PETER A. BOWLER, Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697-2525 and Vanessa Beauchamp, Steven Bekedam, Jason Davis, David Hooke, Steven Jones, Mari Ohara, Kenneth B. Pierce, Jr., Tarek Tabshouri, N. Dennis Ungamrung and Connie Yen (Undergraduate students).

Abstract. Transplantation of seedling and mature coastal sage scrub canopy species is a successful way of salvaging plants and supplements restoration efforts. Re-created habitat patches of ca. 10 m diameter established at several restoration sites saw immediate California gnatcatcher use and served as inoculum sources, producing large plumes of seedling recruitment. Transplanted seedlings have high survival rates and experiments transplanting the largest individuals of species (mature canopy plants) survive if moved during the rainy season, especially Artemisia californica, Salvia mellifera, Encelia californica and Eriogonum fasciculatum. Data for other species are also reported.

Donor Site values: É As seed sources - collection can be intensively pursued for years before their elimination: over a four year period ca. 450 lbs of seed were collected from a small on-campus site to be developed in the near future É Sources for recruitment plants, or seedling collection - transplants are mycorrhizal from natural stand association (site specific inoculum); over the past four years over a thousand seedlings and second tier plants were collected from oncampus sites which are being developed É Sources for mature, canopy forming adults - which bring epiphytes (lichens, algae), invertebrates, and so forth when transplanted É Genetic integrity - the origin of seed, seedlings and adult plants are from a single locality É Soil - bringing with it mycorrhizae and the cryptozoic community É These sites can farmed; "doomed" stands are possible sites into which seed can introduced, even watered, to generate mycorrhizal recruitment plants Restoration Host sites values: É Seed sources - exceptional seed production usually occurs when canopy plants are transplanted, which can be harvested or left to further seeding of a restoration site É Sources of seedlings - extraordinary self-seeding results in large numbers of recruitment plants, which can be harvested since they diminish in number in any event due to competition for water, light and space É "Instant habitat" attraction/effect for birds, mammals and invertebrates that use canopy habitats when transplanted Wild grown canopy plants jumpstart restorations

Salvage, "rescue," and relocation of living material has been employed in many habitat types, and both plants and animals have been relocated with varying success as anthrogpogenic needs encroach on natural areas. In Europe special interest clubs of amateurs capture lizards, other animals, and attempt to move plants when a site is threatened, even if only common species are present. Transplantation of oaks with variable success, and mechanically scooping wetland material and moving it to a restoration site, are common practice, and there are examples in many other habitats. While transplantation of one kind or another has been tested and is used in a diversity of habitats, it has not been tried in a systematic way or on a large scale for coastal sage scrub. In a sequence of experiments beginning in 1992, coastal sage scrub plants ranging from seedlings to mature plants have been transplanted into a series of sites to test the feasibility and survival of transplants from natural stands which are destined for development. Donor stands in areas which are to be developed are excellent study sites for salvage experiments because they allow manipulative experimentation without damaging natural stands in protected areas. Ideally such sites can be located long in advance of impending development, so that they can be harvested over a period of years for seed, seedlings, larger recruitment plants, adult plants, and eventually soil. Host sites should be carefully selected as well, so that donor and host match to the extent possible in exposure, slope, soil type, drainage, and so forth.

Seedling Transplantation

In 1992 a south facing bluff in the UC Natural Reserve System's San Joaquin Marsh Reserve was planted with seedlings collected from the UCI campus. After approximately a year, mortality was low in Encelia californica (4%), in Artemisia californica (5.5%), Eriogonum fasciculatum (13.8%), and higher in Lotus scoparius (24%). This compares favorably with commercially grown, mycorrhizal inoculated nursery plants. A survy of a large planting at Crystal Cove State Park indicated higher mortalities for Encelia (25%), Artemisia (18%), Eriogonum (21%), though mortality was low in a number of other taxa (Salvia mellifera [7%], Isocoma menziesii [4%], Rhus integrifolia [8%], 27% in Isomeris arborea, and60% in Heteromeles arbutifolia. For the composite planting of that particular Crystal Cove project, 524 of 730 plants survived (72% survival); another Crystal Cove planting experienced 21% mortality in a planting of 542 commercially produced plants. Survival of transplanted, wild grown, seedlings was competitive with commercial product survival (Bowler, et al., 1994).

Immature Plant Transplantation

In 1993 a site ("Site 3") in UCNRS Marsh Reserve was selected for an experiment transplanting immature though larger than seedling sage scrub plants. This site was occupied by closed canopy artichoke (Cynara cardunculus), which was eradicated with glyphosate (Roundup) and raked from the site. This site was a north facing exposure and the restoration emulation was that of an analogous exposure in the UCI Ecological Preserve, the nearest neighbor sage scrub stand. This was an exceptionally successful planting, with Artemisa californica, Encelia californica, Eriogonum fasciculatum, Isomeris arborea and several other taxa becoming rapidly established, with most species flowering and setting seed the first season after planting. The site was not watered or tended. A remarkable proliferation of seed was evident at the site, which by its second year had a density of 180-200 Artemisia seedlings per square meter; the third year after planting this had thinned to 94 per square meter with a closed canopy understory in most of the plot. Interestingly, this site was not plagued with artichoke after the original eradication. The site has been used by gnatcatchers since the second year after planting.

Table 1. Species which have been successfully transplanted either directly (from site to site) or being held briefly in a greenhouse to reduce transplantation shock. The wetland taxa were transplanted in the UC Natural Reserve System's San Joaquin Marsh (3,500 plants) and the sage scrub species were transplanted to bluffs in the Marsh Reserve and to the UCI Ecological Preserve, with donor sites from the UCI Campus and nearby private land (Buck Gulley).

Amaryllidaceae Dichelostemma capitatum + Nearly all survive; they can be held in a shadehouse in pots; outplant in the winter Asteraceae Baccharis spp. + Easily grown from cuttings; actual transplantation not readily accomplished in large plants Anacardiaceae Malosma laurina + As seedlings - Adults are extremely difficult to move Rhus integrifolia + As seedlings - Adults are extremely difficult to move Asclepiadaceae Asclepias fasciculatus + Asteraceae Artemisia californica + Nearly 100% survival as seedlings; tranpslant in winter or hold in a greenhouse till winter for introduction to host site + Variable but high success for adults depending upon care in extraction; must be done in winter; large seed set, self-seeding Encelia californica + Large plants lose leaves; hold in greenhouse prior to outplanting; large seed set, self-seeding Isocoma veneta var. vernonioides + Moderate success Cactaceae Opuntia littoralis + Easily propagated/transplanted Optuntia prolifera + Easily propagated/transplanted Crassulaceae Dudleya lanceolata + Dudleya pulverulenta + Cyperaceae Eleocharis palustris + Scirpus americanus Pers. + Scirpus californicus + Scirpus maritimus + Fabaceae Lotus scoparius - Transplants well as a seedling, difficult as an adult (topping the plant significantly enhances survival) Iridaceae Sisyrinchium bellum + Juncaceae Juncus balticus Willd. var. balticus + Lamiaceae Marrubium vulgare + This exotic has nearly 100% survival (I removed 120 successful direct transplants made by convicts whose taxonomic astuteness was limited) Salvia mellifera + Shallow fluffy roots; easy to extract; move in the winter; abundant seed production, a few germinate onsite

Liliaceae Chlorogalum pomeridianum + Zigadenus fremontii Torr. +? Experiment underway var. fremontii Malvaceae Malacothamnus densiflorus - Difficult Orchidaceae Habernaria unalascensis - Single attempt failed Paeoniaceae Paeonia californica - Difficult (easier from seed) Poaceae Leymus condensatus + Ramet sections have nearly 100% survival Melica imperfecta +? Experiment underway Nassella lepida + Nassella pulchra + Polygonaceae Eriogonum fasiculatum + Seedlings transplant, adults poorly (hold in a greenhouse) Primulaceae Dodecatheon clevlandii + Rosaceae Heteromeles arbutifolia - Easy as a seedling, very difficult to transplant adults (deep roots) Rosa spp. + Commonly grown from cuttings; transplantation more difficult Saliciaceae Salix app. + Commonly grown from cuttings; transplantation possible but not easy Saxifragaceae Ribes speciosum + Scrophulariaceae Mimulus aurantiacus + Easy to transplant Typhaceae Typha latifolia (and others) +

Translocation of Mature Plants by Bulldozer

Numerous attempts, many successful in part, have been made to simply scoop up sage scrub and move it with a bulldozer. This approach is limited to sites which have a relatively level topography and a soil horizon deep enough to allow mechanical removal. At UCI twelve large Salvia mellifera and twelve Eriogonum fasciculatum specimens were carefully excavated, moved and watered for several months. After a year, all of these plants survived, although branches and portions of many did not. These large plants saw gnatcatcher use for several months during the year.

Transplantation of Adult Canopy Plants by Hand-Excavation

In 1996 a series of experiments were initiated transplanting the largest canopy plants found in the donor site. Plants were moved to nine "pods" or closed canopy patches ca. 10 m in diameter in two 3.5 acre sites formerly densely occupied by artichoke and black mustard. The two large sites were selected because they lay outside gnatcatcher territories, and it was hoped that birds would be attracted. Gnatcatchers did used both sites periodically, as well as the mechanically (bulldozer) moved black sage and buckwheat plants. Monotypic stands were used for consistency of comparison and because this emulated the UCI Ecological Preserve habitat adjacent the restorations. The pods were constructed ca. 30 meters apart, again simulating habitat in the Preserve. Transplantation success as indicated by survival for very large sage scrub canopy plants after a year was substantive, with 1% mortality in an Artemisia californica pod of 109 tagged plants and 6% mortality in another Artemisia pod of 125 plants. Twenty very large Salvia mellifera specimens, the largest we could find in a very old donor stand, showed 65% survival after a year, with all of the survivors flowering and producing seed; a single seedling was located beneath this stand. These old shrubs had an abundance of epiphytic lichens on them (both crustose and foliose) which appear intact after a year. Survival of large Encelia californica (up to 130 cm in height) was substantive, with only a single mortality of fourteen transplants. Buckwheat exhibited a much higher mortality incidence, with only 41% of the large adults still living after a year. Large Lotus scoparius are difficult to transplant because of their deep taproot; only 19% survived and flowered of ninety-nine plants moved. It should be noted that none of these transplanted were topped or pruned since retaining canopy with its structure and invertebrates was part of the object of the project; if these species are trimmed, survival is higher, though canopy must regrow. The results of over a thousand transplants will be presented in a forth-coming publication. Root structure on large plants is an important determinant in transplantation success among mature canopy plants, and the degree to which a species is able to shed leaves is also important. In general, species with shallow, fluffy roots that can form platforms - such as Artemisia californica, Salvia mellifera, Mimulus, and Isocoma spp. - exhibit greater survivorship than other root designs. Buckwheat with its long ropy root system has relatively poor survival and does not lose its leaves. Encelia transplants well and has an intermediate root system. Encelia loses its leaves often after transplant, but recovers rapidly. Species such as Malosma laurina, Rhus integrifolia, and Heteromeles arbutifolia have deep root systems, and do not regrow leaves if they are lost. These are all difficult to transplant when adult and are not feasible for hand techniques. Out of approximately thirty large Rhus specimens extracted by hand, eighteen died in the greenhouse prior to outplanting, and of twelve live plants transplanted to a restoration site, only five survived after a year. Timing for transplantation is also critical. Winter transplantation is essential for maximizing survival, and all transplanted adults require watering at least for a few weeks (though watering can be stopped at the end of the rains if planting occurred in the fall). Part of the need for winter planting lies in the appearance of winter foliage in seasonally dimorphic species. If Artemisia, for example, is transplanted before winter leaves appear, mortality is significantly greater. This is somewhat counter-intuitive since it might be anticipated that planting during dormancy might be advantageous, but that does not appear to be the case. Mature plants produce an enormous seed rain, with high densities and outlying seedlings appearing up to nine meters from pods (for Artemisia). Densities of Artemisia germinations reached nearly 10,000 per square meter, with complete cover in a carpet beneath the pods (even if the large plants died). This rapidly thins to a lower recruitment level. At Site 3, densities at year two were 180-200 seedlings per square meter, and the same quadrats showed a lower seedling presence at 94 plants per square meter at year three. (These high seedling densities, however, make harvest and outplanting from pods an easy matter, thus, a restoration project can become its own seedling producer.) "Self seeding" after the first year was observed by Artemisia at all sites, and by Isomeris at Site 3. Approximately five pounds of Artemisia seed was collected from several large pods - which still had substantive seedling production beneath them.

Use by Native Molluscs

The native landsnail Helminthoglypta tudiculata has colonized the adult transplant patches, with six individuals being seen in them. Helix aspersa, the introduced European snail which is abundant in mesic landscaped settings, is broad ranging and many individuals have been found on the site. Because the site has a boundary on one side with a university faculty and staff housing development, this species will likely be present, however, H. aspersa does not prefer sage scrub habitat and populations are low. Otala lactea, the Old World Spanish milk snail, is present on the University campus but only a single individual has been found on the restoration site. This species appears to be better at resisting desiccation than H. aspersa, and can be seen estivating like Christmas decorations on Brassica nigra. Though discovered colonizing the UCI Ecological Preserve in the past several years, like H. aspersa sage scrub in not a preferred habitat, though it does occupy more xeric disturbed habitats dominated by exotic plants than H. aspersa. In addition to the restoration on the Ecological Preserve, Helminthoglypta tudiculata has been found in several small restoration sites at the UC Natural Reserve System's San Joaquin Marsh Reserve. A remnant population exists nearby, and it is not impossible that the native landsnail may have pre-existed where the restorations occurred, rather than followed and colonized new sage scrub habitat. The decollate snail, a voracious predator introduced as biological control for Helix aspersa, existed at Site 3, where it had followed the mesic environment of San Diego Creek from landscaping in Irvine. This exotic predator was collected at several sites along three kilometers of the creek, and may explain why Helminthoglypta is absent from the sage scrub restoration at Site 3. Though found at the site when it was dominated by a dense, monotypic stand of Cynara cardunculus and in the first two years of the restoration project, decollate snails have not been collected at the site since it became nearly closed canopy sage scrub. The decollate snail, like Helix aspersa and the argentine ant, is another example of a landscape and water following exotic which can pre-exist at or invade restoration sites from either adjacent urban settings or along drainages leading from them. At least in one case, a population of decollate snails pre-existing at a site dominated by artichoke appears was displaced when a restoration matured to become closed canopy sage scrub.

Shielding and Protection of Seedlings by Exotics

In the early stages of restoration at sites historically dominated by exotics, one of the big challenges is allowing native seedlings to survive in the face of a rapidly growing wave of exotics which compete for water, space, and eventually form canopies excluding the more slowly growing natives. An irony observed by many restorationists is that to a point these exotic sun screens allow seedlings to flourish.

Economics

Is salvage economical? It should be remembered that it is difficult to put a price on canopy plants which could be many decades old, are mycorrhizal, arrive with a natural invertebrate fauna living in them, and have late successional epiphytes like lichens which take a long time to enter a community. The recruitment seedling population in a donor site can be collected rapidly with little effort and placed directly in gallon containers to grow for later planting, or simply stored in liners for rapid planting. Thus wild grown mycorrhizal seedlings are nearly free. Larger, pre-canopy plants which are still in the gallon size can be collected and potted for the price of the pot and a gallon of cactus mix (if onsite soil is not used). Gallon container plants cost in the vicinity of $2.85 each if purchased (using Artemisia californica as an example). In a recent experiment conducted by Habitat West and The Irvine Company with my advice, 800 plants were excavated from a "doomed" donor site and moved to a host site where they were placed in three pods. This cost $3,000, though it should be noted that there was some volunteer assistance. Thus these large plants were moved using commercial techniques at a cost of $3.75 per plant. Unfortunately the plants were put in the ground and received no subsequent watering or weeding, thus mortality was much greater than in tended pods at other experimental sites. Salvage plants supplements plants propagated for restoration, as well as forming patches of canopy in larger, imprinted or directly seeded matrices.

Longterm Survival

Do these middle aged or old plants live long after transplantation - or is it just a flash in the pan? Does that matter? Dead plants occur in natural stands anyway, and if transplanted in the fall, most adult plants shed seed on site even if they don't survive. It is too early to answer that question. Transplanted seedlings mature rapidly at normal growth rates and do not appear stressed - there is no reason to suspect that they would die early. Second year transplants also show no sign of slowed growth or stress. Large plants appear to produce exceptionally large seed sets, perhaps a result of stress, and if they are watered, flowering and seed set occurs very early (seeds are ripe in late August in A. californica, for example). This a benefit in a restoration setting in that seed is down before the first rainfall, and if it is collected, then similarly it can be applied prior to rains.

Use of Adult Patch Transplants by Birds and other Vertebrates

Point counts were made at the canopy transplant restoration sites, and indicate that birds used the open, imprinted matrix area as well as the canopy itself. The birds recorded are similar to those detected in point counts in sage scrub on the Preserve, and include roadrunners, killdeer (open area), mourning doves (open area), Anna's hummingbird, white crowned sparrow (more abundant in the canopy transplant than in nearby sage scrub), black phoebes, lesser American goldfinch, California gnatcatcher (use from spring through December; occasional other sightings on the patches), northern flicker, California towhee, mocking bird, Say's phoebe, and the western kingbird. On the basis of a pitfall trap study currently underway and observations of the site, animals associated with the restoration plots include red racers, gopher snakes, kingsnakes, alligator lizards, western fence lizards, skinks, sideblotch lizards, California ground squirrels, cottontail rabbits (heavy herbivores on Nassella) and coyotes. These studies are ongoing and will continue as sage scrub infilling occurs.

Conclusion

Over a four year period over a thousand seedling and immature canopy forming plants and more than a thousand mature canopy plants were transplanted from doomed natural stands to restoration sites. Our research suggests that transplantation and salvage can play a vital role in establishing canopy plants and many understory plant species. For a number of reasons, transplanting wild grown plants appears to hasten the development of fledgling communities, and this approach shows particular promise as inocular sources when planted as patches within a larger matrix of imprinted or direct seeded approaches. Seedlings of most species can be transplanted easily with a very high survival rate. The larger the plant, the more species are segregated according to root type and degree to which strategies such as deciduousness can be used to avoid transplantation stress. Transplantation for both immature and mature plants was most successful in the winter, with survival decreasing the later the planting or if the transplantation was attempted prior to the production of winter foliage. A comprehensive paper presenting the results of the past four years of research will soon be published, and will elaborate other aspects of this study.

Acknowledgments

We thank the University of California Natural Reserve System for permission to conduct experiments in the UCNRS San Joaquin Marsh. This study was funded in part by a grant from the Transportation Corridor Agencies to the University of California. We are also grateful to the many students in Restoration Ecology (Biology 175) and undergraduate research students who assisted in implementing these experiments over the past four years.

Literature Cited

Bowler, P.A., A. Wolf, H.V. Pham, M.A. Archer, A.S. Bak, M. Bedaux, A. Chhun, J.S. Crain, S. Feeney, A. Gloskowski, P. Golcher, C.J. Hodson, M.L. James, R.C. Johnson, M.S. Milane, V.H. Nguyen, R.S. Salazar, and C.R. Simonds. 1994. Transplanting Coastal Sage Scrub Seedlings from Natural Stands (California). Restoration and Management Notes 12(1): 87-88.

Bowler, P.A. 1992. Biodiversity Conservation in Europe and North America. II. Shrublands - In Defense of Disturbed Lands. Restoration and Management Notes 10(2): 144-149.

Bowler, P.A. 1997a. New Directions in Coastal Sage Scrub Restoration: Establishing Local Species Richness, Ethics and Effort in Onsite Seed Collection, GIS Applications and a New Approach to Longterm Project Design and Performance Standards. in P.A. and E. Read (eds.). Coastal Sage Scrub Restoration: Proceedings of the Coastal Sage Scrub Restoration Symposium held at the Fifth Annual Conference of the Society for Ecological Restoration. Published by Society for Ecological Restoration, California Chapter (in press).

Bowler, P.A. 1997b. Species Richness and Coastal Sage Scrub Restoration. in Bowler, P.A. and E. Read (eds.). Coastal Sage Scrub Restoration: Proceedings of the Coastal Sage Scrub Restoration Symposium held at the Fifth Annual Conference of the Society for Ecological Restoration. Published by Society for Ecological Restoration, California Chapter (in press).