Transplantation of Understory Bulbs, Grasses, Lichens and Bryophytes in Coastal Sage Scrub Restoration
PETER A. BOWLER, Department of Ecology and Evolutionary Biology, University
of California, Irvine, CA 92697-2525,
and Vanessa Beauchamp, Kenneth B. Pierce, Jr. and Tarek Tabshouri (Undergraduate
students).
Abstract. Understory species in coastal sage scrub are often overlooked
both in restoration projects and in salvage attempts.
Perennial bulb species, several grasses, lichens and bryophytes have
been experimentally transplanted into reconstructed
coastal sage scrub sites, with significant success. This approach is
worthy of consideration in salvage efforts for coastal sage
stands destined to be eliminated for development.
Understory elements of coastal sage scrub are challenging to introduce
in restoration projects. Despite their importance in terms
of species numbers and temporal dominance, they are often omitted from
mitigation projects and are viewed as problematic in
whole community restorations (Bowler, 1997a, 1997b). The fact that
native understory annuals, especially, compete directly
with faster growing exotic taxa which frequently form closed canopies
(grasses and black mustard, for example) makes
re-introduction early in the restoration process difficult, though
this is not the case for perennial bulbous plants or cryptogams.
Lichens, mosses, liverworts and bulbous species were experimentally
introduced from a "doomed" donor site to a well
established canopy sage scrub project, which was planted in 1993 with
Artemisia californica Less., Encelia californica Nutt.,
Isomeris arborea Nutt., Eriogonum fasciculatum Benth. var. fasciculatum,
Lotus scoparius (Nutt.) Ottley and Isocoma menziesii
(Hook. & Arn.) Nesom var. menziesii using recruitment plants grown
in the wild at a natural stand. Prior to 1993 the host site
("Site 3"), a north facing exposure in the UCNRS San Joaquin Marsh,
was a monoculture of Cynara cardunculus L. (globe
artichoke). Site design was an emulation of an analogous exposure in
the UCI Ecological Preserve, the nearest neighbor intact
stand. This site rapidly developed a nearly closed canopy and the presence
of bryophytes suggested that it was an appropriate
site and time in the restoration sequence for the introduction experiment.
Because of the historic occupation by artichoke, there
was not a seed bank of black mustard or annual grasses, and very few
artichoke germinated at the site. Dudleya pulverulenta
(Nutt.) Brit. & Rose, Dichelostemma capitatum A. Wood, and Chlorogalum
pomeridianum (DC.) Kunth were introduced as
transplants as early as 1994 and are well established onsite. Zigadenus
fremontii Torr. var. fremontii and Dudleya lanceolata
(Nutt.) Brit. & Rose were also recently transplanted to the site
and appear to be surviving. To implement the terricolous lichen
(soil) transplants, a metal sign used to skim the top 10 cm or so of
the soil surface. The slice was carefully placed in a flat, and
was then outplanted, so that the same configuration and density of
lichens were present in the inocular slab as in the natural
donor site. Other approaches were tried as well. Terricolous lichens
(predominantly Cladonia species) were fragmented by
hand crushing, and were spread in quarter m2 plots. (A similar transplant
experiment was initiated for biotic crusts from the
same locality, Buck Gully near Corona del Mar.) In another experiment,
substrate samples colonized with lichens (limbs, sticks,
and so forth) were used as inocular substrates within the quadrats.
Another approach being tested at a site in the Ecological
Preserve is attaching lichens/sticks to not colonized but suitable
substrates (for example, a mature specimen of black sage which
is a favored substrate for the lichen species on the attached branch).
A final approach was macerating lichen thalli and applying
the ground material to plants (painting it on as a slurry). Disk transplants
are frequently experimentally used in lichenological
studies, and horticultural movement of moss species from one site to
another is common. For lichens, bryophytes and
liverworts, site selection is extremely important, since these groups
have critical micro-habitat and micro-climate requirements.
If the wrong site of introduction is selected the species will simply
not colonize and will die. For example, in 1988 four Quercus
agrifolia with five lichen species inhabiting them were planted on
the UCI campus (Bowler and Riefner, 1990), however, within
half a dozen years all of the lichens had perished, though the oaks
continued to grow. A pilot study was initiated in 1996 in
which four plots of lichens (Cladonia sp.), bryophytes, and liverworts
were transplanted. Unfortunately three of the plots were
lost through road repair, however, the fourth plot survived with the
Cladonia and at least one liverwort species persisting after a
year. Since the current more extensive study of lichen, bryophyte,
and liverwort transplantation and subsequent colonization
(from quadrat frames delineating the plots) was only recently implemented,
it is too early do more than hope that this broader
study will do as well as the sole pilot plot. Native bunch grasses
can be transplanted from the wild, particularly if they are held
in a greenhouse for several weeks to reduce transplant shock. Seventy-five
plants of Nassella lepida (Hitchc.) Barkerworth
were transplanted using this method, and all survived as understory
beneath an Artemisia canopy. Nassella pulchra (Htichc.)
Barkerworth can also be transplanted, and experiments have been planted
to test the survival of Melica imperfecta Trin.
Leymus condensatus Presl. is also easy to transplant, with rapid growth
arising from transplanted ramets. An attempt to
transplant an individual of Habernaria unalascensis (Spreng.) Wats.
was unsuccessful.
Conclusion
The introduction of bulbous plants, Dudleya species, and grasses (some
still undergoing study) is easily accomplished and can
be broadly used in a restoration context. Preliminary data suggest
that terricolous lichens can be directly transplanted into
understory micro-habitats, but establishment of only one lichen species
(Cladonia sp. in the chlorophaea aggregate) has been
confirmed twelve months after transplantation. Data for recent experimental
transplants of bryophytes, liverworts (aside from
one successful transplant) and terricolous lichens will be published
after establishment or transplant failure has been determined.
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.
Literature Cited
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 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).
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).