Conservation Action Plan
Opuntia corallicola
Species Name: Opuntia corallicola (Small) Werderm.
Common Name(s): Florida semaphore cactus, Key’s semaphore cactus
Synonym(s): Opuntia spinosissima Miller (1768), Cactus spinosissimus (Miller)
Martyn (1771), Consolea spinosissima (Miller) Lemaire (1862), Consolea corallicola
Small (1930) (Austin 1980). Extensive discussion of taxonomy in Bradley and Gann
(1999).
Family: Cactaceae
Species/taxon description:
Shrub or small tree 1-3.5 m (3.3-11.5 ft) tall, trunk cylindrical; branches usually grow in
one or multiple planes from the trunk; copiously spiny, gray or white, in all areoles or
some joints nearly spineless, spines not barbed; flowers orange turning to red as they
age (Bradley and Gann 1999), unfertilized flowers revert to vegetative branch or drop as
dispersal unit; fruits yellow (Coile 2000, Austin 1998).
Legal Status: Florida endangered, critically imperiled (FNAI), Federal candidate.
Biogeographic Value: Endemic.
Prepared by: Jennifer Possley, Meghan Fellows and Cynthia Lane, Samuel J. Wright,
Conservation of South Florida Endangered and Threatened Flora, Research Department,
Fairchild Tropical Garden
Last Updated: June 2004 (Wright and Maschinski)
M. Fellows
Background and Current Status
Range-wide distribution – past and present
Florida: (confidential)
Population and reproductive biology/life history
Annual/Perennial: Perennial
Habit: Shrub/Small Tree
Short/Long-Lived: Long
Pollinators: Bees, hawkmoths, hummingbirds, bats? (Bradley and Gann 1999). Birds?
(Austin et al., 1993). The pollinator for O. corallicola is unknown.
Flowering Period: Flower throughout the year, peaking December to April (NegronOrtiz, 1998). Peak in February and March (Bradley and Koop 2003)
Fruiting: Rare; Laura Flynn (The Nature Conservancy) tried to pollinate flowers and
got viable fruit, but when planted, they failed to thrive.
Annual variability in Flowering: unknown
Growth Period: a study by Bradley and Koop (2003) showed that juveniles (plants
without pads) had significant growth between August and November, while adults
(plants with pads) showed significant growth between April and June.
Dispersal: Primarily through dropped pads that have spines.
Seed Maturation Period: unknown
Seed Production: low and infrequent
Seed Viability: Fruit collected prior to May 1995 (no seed germinated), and twice in
1997 (June/July collection -seeds did germinate, July 7, 1997 fruits/seeds were not
successfully germinated) (Vlcek, 1997).
Regularity of Establishment: Never observed from seed, easy from dropped pad in
fresh water.
Germination Requirements: unknown
Establishment Requirements: It is unknown whether the cactus roots better in one
season than another.
Population Size: (confidential)
Annual Variation: Slow decline in number of adults, random in number of rooted
pads.
Number and Distribution of Populations: (confidential)
Habitat description and ecology
Type: MARITIME HAMMOCK, COASTAL STRAND. Low buttonwood
transition areas between rockland hammocks and mangrove swamps and possibly other
habitats such as openings in rockland hammocks (Gann et al. 2002); Rocky hammocks,
coastal barrens (Coile 2000); Research suggests that different habitats are better for
newly establishing plants vs. established plants.
Physical Features:
Soil: Cracks in limestone or shallow soil, sand (Austin, 1980); “Like its
associates, the tree cacti this semaphore grows on almost bare rock. Soil is
scarcely necessary; a little humus about the roots seems to be sufficient to
furnish it with food” (Small, 1930).
Elevation: < 1.5 meter above sea level
Aspect: unknown
Slope: unknown
Moisture: unknown
Light: Studies have tested growth and survival in full sun vs. shade. Results
showed many interactions. Plants in shade survived, but did not grow well;
plants in sun grew, then died. At Site 94, the adults are in a mixture of sun to
shade, although adults in shade appear healthier than adults in sun. At Site 166,
all plants are on the edge of a hammock, in partial shade.
Biotic Features:
Community: “It is to be expected on any of the Florida Keys where there are
primeval hammocks” (Small, 1930); at Site 94, occurs in a low buttonwood
transition area between rockland hammock and coastal swamp. (O.
spinosissima). Bare rocks with slight covering of humus in jungle hammocks
near sea level (Benson, 1984). At Site 166, plants occur in the ecotone between
mangroves and hammock species.
Interactions:
Competition: unknown
Mutualism: unknown
Parasitism: unknown
Host:
Other: unknown
Animal use: One experimental outplanting appeared to be trampled by
deer – perhaps they were eating the cacti or browsing nearby.
Natural Disturbance:
Fire: highly unlikely
Hurricane: Hurricane Georges caused some damage to the plants;
however hurricanes could be viable dispersal mechanism and increase
the number of rooted plants
Slope Movement: unknown
Small Scale (i.e. Animal Digging): unknown
Temperature: unknown
Protection and management
Summary: Ninety-six clones were planted in 1996, but these populations continue to
decline due to a pathogen, deer trampling, etc (Stiling, Rossi and Gordon, 2000).
University of South Florida: Dr. Peter Stiling of USF is attempting a reintroduction on
Site 167 (Bradley and Gann 1999). The Cactoblastis moth (Cactoblastis cactorum) is
being monitored at one site by The Nature Conservancy and Stiling.
Availability of source for outplanting: (confidential)
Availability of habitat for outplanting: (confidential)
Threats/limiting factors
Natural:
Herbivory: The moth Cactoblastis cactorum is a major problem (Johnson and
Stiling, 1996). Larvae much prefer O. corallicola to the other Opuntia species.
The Nature Conservancy had placed protective cages over the cacti (Stiling,
Rossi and Gordon, 2000), but they are now removed. No moth activity was
observed in 228 plants of Opuntia corallicola at Site 166 (Pemberton, pers.
comm.).
Disease: Unknown pathogen or fungus attacking juveniles (Bergh, pers. comm.)
Predators: Key deer trampling (Stiling, Rossi and Gordon, 2000)
Succession: unknown
Weed invasion: Exotic plants Schinus, and Colubrina (Bradley and Gann,
1999); although little has been seen recently at the two wild populations.
Fire: very rare in habitat
Genetic: The cacti at Site 94 ar not reproducing sexually; the original 12-13 are
probably sterile polyploids derived from a single parent plant (Negron-Ortiz,
1998). Genetic studies have suggested that there are more than one genetic
individual at the Site 94 (The Nature Conservancy, unpubl. data, 2001). It is
unknown how many genetic individuals are in Site 166 population or if they are
capable of reproducing sexually. Ongoing studies at Fairchild are addressing the
genetic diversity and relatedness of the wild populations.
Anthropogenic
On site: Collectors (Bradley and Gann, 1999; Alcorn, 1990)
Off site: Development, pollution.
Collaborators
The Nature Conservancy, Institute for Regional Conservation, Biscayne National Park,
The Florida Fish and Wildlife and Conservation Commission
Conservation measures and actions required
Research history:
The genus Opuntia originated in northern South America and later spread to the
Caribbean, where it further diversified (Alcorn, 1990). Opuntia spinosissima was first
discovered in South Florida in 1919. Historically, populations existed on Big Pine Key
(now that land is residential) and Key Largo (Small, 1930). A population of 30 adults
also existed on Big Torch Key. The population on Big Torch was extirpated by
construction US 1, although plant enthusiasts reportedly moved some of the plants to
protected public or private areas (Kernan, undated). The species was considered extinct
in the wild. Then, a population of 16 adult Opuntia spinosissima was discovered on Site
94. This population may have been introduced from nursery stock cultivated from wild
populations (George Avery’s field notes, as cited in Alcorn, 1990). In 1989, Carol
Lippincott discovered Cactoblastis cactorum on Opuntia stricta plants in the Keys. In
1990, Cactoblastis cactorum larvae killed one of 13 remaining O. corallicola plants.
Sometime in the late 80’s or early 90’s The Nature Conservancy purchased the land
where O. corallicola was growing and designated it a preserve. By 1993, Florida
Atlantic University, Fairchild Tropical Garden, The Nature Conservancy, University of
South Florida, and USFWS had formed an O. corallicola recovery team.
Austin and Binninger (1994) found that the Florida semaphore cacti are actually
not O. spinosissima and should properly be called O. corallicola. This means the
species is extremely endangered.
Fairchild Tropical Garden received a grant from the National Biological Service
from July 1, 1995 to July 1, 1996 to study “Conservation of Opuntia spinosissima in the
Florida Keys.” Project goals were to “re-establish O. spinosissima in appropriate
protected habitats through a carefully monitored reintroduction program and to increase
our knowledge of the species’ reproductive biology.” Collaborators included the Nature
Conservancy, University of South Florida, Florida Department of Environmental
Protection, state and county natural resource agencies, and the National Key Deer
Refuge. Reintroduction sites were Site 94, and Site 168. The source of plants for
translocation was the 12 plants on Site 94.
Peter Stiling, Kit Kernan, Doria Gordon, Anthony Rossi and Steve Karl applied
for a National Science Foundation grant to study the relationship of Cactoblastis
cactorum and Opuntia corallicola. (A publication appeared in Biological Conservation
in 2000).
Peter Stiling (1996) reported to Doria Gordon that the outplantings on Site 94
have gone well.
Gordon and Kubisiak’s (1997) RAPD analysis supported Austin and
Binninger’s belief that O. corallicola and O. spinosissima are two separate species.
Vivian Negron-Ortiz (1997) completed her reproductive studies and published a
paper saying that the plants may be sterile polyploids.
Kit Kernan (1998) wrote a report about the results of Fairchild Tropical
Garden’s reintroduction and monitoring efforts. The study showed that survival was
lower when plants were in closed canopy hammocks. He suggested that adults do best
in mature hammocks, but juveniles require canopy gaps, which explains why there are
contradictions in the literature describing O. corallicola’s preferred habitat.
A second or additional outplanting occurred at Site 50 under the direction of the
Florida Department of Environmental Protection in 1996. This outplanting has had
some success with approximately 1/3 of the plants surviving to 5 years. Janice
Duquesnel continues to monitor for flowering, recruitment and survival, maintaining an
accurate GIS map and tagging records. Plants were failing to thrive in ‘hammock’ sites
and were removed.
In November of 2001, Keith Bradley and Steve Woodmansee of the Institute for
Regional Conservation discovered a population on a remote island (Site 166) of
Biscayne National Park.
In January of 2002, Bradley led a team of researchers from Fairchild Tropical
Garden and Bob Pemberton from the United States Department of Agriculture back to
the site to assess the distribution and size of the population. During the January visit
Pemberton collected 228 dead cladodes. Lab inspection revealed no evidence of
Cactoblastis cactorum on cladodes. The site was visited another eight times from
August 2002 through June 2003. During the visit plants were tagged, mapped and
monitored for survival, growth, and flowering. Material was collected by Fairchild from
70 individuals to study the level of genetic variation within and between the two
populations. In addition Bradley has surveyed islands containing suitable habitat and
has found no O. corallicola (Bradley and Koop 2003).
In fall of 2002 Fairchild donated 43 O. corallicola plants to the Florida
Department of Environmental Protection. Planted material was grown from collected
cladodes of nine plants from Site 94. Carol Lippincott collected the cladodes in 1990.
Those plants in addition to 15 more were outplanted at Site 50 in February and March
2003. Plants will be monitored for growth, survival and Cactoblastis cactorum
occurrence.
Genetic analysis of populations at Site 94 and Site 166 indicate that they are not
distinct (Wright and Francisco-Ortega 2004). Vegetative reproduction is the main mode
of reproduction in both populations.
USDA researchers are examining effectiveness of biological controls of
Cactoblastis cactorum on many Opuntia species, including O. corallicola.
(Summary of Research in Progress/Completed)
Phenology (Negron-Ortiz, Bradley and Koop)
Genetics (Austin and Binninger, Gordon and Kubiasik, Pipoly, Francisco-Ortega, Lewis
and Carriaga)
Reproduction (Negron-Ortiz)
Cactoblastis (Stiling, Pemberton)
Horticulture (Garvue)
Reintroduction (Garvue, TNC/Stiling, Lane et. al, Duquesnel)
Growth & Survivorship (Kernan, unpublished, Bradley and Koop, Duquesnel)
Mycorrhizae (Fisher)
Establishment (Lane et. al)
Genetic analysis (Francisco-Ortega and Lewis)
Significance/Potential for anthropogenic use:
The pads of some Opuntia spp. are eaten for food.
Recovery objectives and criteria:
There are no federal objectives or criteria for this species.
Management options:
Pest Removal
The population at Site 94 appears to be in decline. Although doing nothing in most
cases won’t increase the rate of the extinction, this species is subject to the invasion of
the Cactoblastis moth. Current management efforts include weekly visits by volunteers,
which remove moth larvae before they can destroy portions of the plants. Over the
course of these frequent visits, a few larvae have hatched creating the need to remove
the diseased pad. This species most likely requires some intervention if it is to survive
the next 10 years, despite the discovery of the new population.
Outplanting
Outplanting success has been low, much more research is need to determine the
necessary requirements for an outplanting. At this point, the most likely to be successful
scheme would create canopy openings in hammocks farther from the coast than current
locations either at the site of the current population or in nearby hammocks. Outplanting
should be used to buffer the species from local extinction risk, given there are only two
wild populations and two outplanted populations.
Hand pollination
Cross pollination of individuals at the two sites may be possible provided that
individuals of both sexes are discovered. The species is somewhat slow growing, so
hand crosses of pollination and whether or not they are successful could take years to
determine.
Next Steps:
Continue monitoring of populations (wild or introduced)
Coordinate more outplantings in suitable habitat
References
Alcorn, P.W. 1990. Element stewardship abstract for Opuntia spinosissima. Florida
semaphore cactus. The Nature Conservancy, Arlington, VA.
Anderson, E.F. 2001. The cactus family. Timber Press, Portland Oregon. (as
Consolea spinosissima).
Austin, D.F. 1980. Status report on Opuntia spinosissima. In: Final report:
endangered and threatened plant species survey in south Florida. USFWS, Office of
Endangered Species.
Austin, D.F. and D.M. Binninger. 1994? Final report on the endangered Florida
semaphore cactus. Report to USFWS.
Austin, D.F., D.M. Binninger, and D.J. Pinkava. 1998. Uniqueness of the endangered
Florida semaphore cactus (Opuntia corallicola). Sida 18(2):527-534.
Avery, G.N. and Loope, L.L. 1980. Endemic taxa in the flora of south Florida. Report
T-558. U.S. National Park Service, South Florida Research Center, Everglades
National Park. Pages 5-6.
Barnhart, J.H. 1935. Chronicle of the Cacti of Eastern North America. Journal of the
New York Botanical Garden. 36(421):1-11.
Benson, L. 1982. The cacti of the United States and Canada. Stanford University
Press, Stanford, CA. Pp 537-538 (IN FTG LIBRARY).
Bradley, K. and G. Gann. 1999. Status summaries of 12 rockland plant taxa in
southern Florida. Report submitted to USFWS, Vero Beach, Florida, October 27, 1999.
Bradley, K.A., and A.L. Koop. 2003. Population monitoring of Opuntia corallicola
(Cactaceae) on Site 166, Biscayne National Park and Status survey in Biscayne
National Park.
Britton, N.L. and J.N. Rose. 1920. The Cactaceae: descriptions and illustrations of
plants of the cactus family. Dover Publications, Inc., New York. Pages 204-205.
Gann, G.D., K.A. Bradley, and S.W. Woodmansee. 2002. Rare Plants of South Florida:
Their History, Conservation, and Restoration. The Institute for Regional Conservation,
Miami, Florida.
Garvue, D. 1994-1996. Various correspondences and memos regarding Opuntia
spinosissima reintroductions in the keys. On file.
Garvue, D. 1997. Conservation of Opuntia spinosissima in the Florida Keys. Final
report to the National Biological Service, Washington D.C.
Garvue, D. 1998. Endangered species profile: Florida semaphore cactus, Opuntia
spinosissima. Garden News (Fairchild Tropical Garden) 53(5):12.
Gordon, D.R. and T.L. Kubisiak. 1998. RAPD analysis of the last population of a
likely Florida Keys endemic cactus. Florida Scientist 61(3/4):203-210.
Howard, R.A. 1982. Opuntia species in the Lesser Antilles. Cactus and Succulent
Journal 54(4):170-179.
Johnson, D. and P.D. Stiling. 1996. Host specificity of Cactoblastis cactorum
(Lepidoptera: Pyralidae), an exotic Opuntia-feeding moth, in Florida. Environmental
Entomology 25(4):743-748.
Kernan, C(?). Late 90s?. Growth and survivorship of the endangered cactus Opuntia
spinosissima reintroduced to the Florida Keys. Was in a file in Cynthia’s office.
13+pp.
Negron-Ortiz, V. 1998. Reproductive biology of a rare cactus, Opuntia spinosissima
(Cactaceae), in the Florida Keys: why is seed set very low? Sexual Plant Reproduction
11:208-212.
Small, J.K. 1930. Consolea corallicola—Florida semaphore cactus. Addisonia 15:2526, pl. 483
Stiling, P. 1992. Report on the spread of Cactoblastis cactorum and its effects on
native Florida cacti, and in particular, the rare semaphore cactus Opuntia spinosissima.
Unpublished report sent to Doria Gordon.
Stiling, P. No Date. Final report on Cactoblastis cactorum and its effects on native
Florida cacti. Unpublished report sent to Doria Gordon.
Stiling, P., A. Rossi, and D. Gordon. 2000. The difficulties of single factor thinking in
restoration: replanting a rare cactus in the Florida Keys. Biological Conservation
94:327-333.
Wright, S.J. and J. Francisco-Ortega. 2004. Determining Genetic Structure between
populations of Opuntia corallicola. In Maschinski, J., K. S. Wendelberger, S. J. Wright,
H. Thornton, A. Frances, J. Possley and J. Fisher. Conservation of South Florida
Endangered and Threatened Flora: 2004 Program at Fairchild Tropical Garden. Final
Report Contract #007997. Final Report to Florida Department of Agriculture and
Consumer Services, Division of Plant Industry, Gainesville, FL.