Pilosocereus robinii - (L.) Byles & Rowley
Key Tree Cactus
Synonym(s): Cereus robinii (Lem.) L. Benson
Taxonomic Status: Accepted
Related ITIS Name(s): Pilosocereus robinii (Lem.) Byles & Rowley (TSN 504398)
Unique Identifier: ELEMENT_GLOBAL.2.142546
Element Code: PDCAC0Z020
Informal Taxonomy: Plants, Vascular - Flowering Plants - Cactus Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Caryophyllales Cactaceae Pilosocereus
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Concept Reference
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Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Pilosocereus robinii
Taxonomic Comments: Kartesz (1994) and others have recognized two varietal entities: var. robinii and var. deeringii. However, according to Linda Chafin (e-mail to K. Maybury, 6/17/97), current research indicates that the differences between these two entities is ecotypic and does not justify taxonomic recognition. However, Kartesz (1999) recognizes the varieties.  Hunt et al. (2006) do not recognize P. robinii as a distinct species, including it as part of the more widely distributed P. polygonus.  More recently, per Alan R. Franck, University of South Florida (pers. comm., 2017), P. robinii and P. polygonus are considered distinct;  the woolly flower bases of Pilosocereus polygonus are quite different from P. robinii (or P. bahamensis) with short or inconspicuous hairs below the flowers.
Conservation Status
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NatureServe Status

Global Status: G1
Global Status Last Reviewed: 10Aug2009
Global Status Last Changed: 18Jun1997
Rounded Global Status: G1 - Critically Imperiled
Reasons: Known from the Florida Keys and Cuba and rare throughout its range, with only 7 occurrences believed extant in the United States. Since the mid-1990s, significant declines have been observed at the Florida Keys sites. The species is subject to cactus collection and its limited habitat is disappearing rapidly due to encroaching development and agricultural conversion; only a few of the occurrences are formally protected. It is also threatened by increasing soil salinity due to sea level rise and storm surge; hurricanes are also occassionally destructive to the few populations. Sea level and storm impacts are predicted to worsen as climate change proceeds, especially given that there is limited connectivity between this species' habitat and higher ground.
Nation: United States
National Status: N1

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Florida (S1)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered (19Jul1984)
U.S. Fish & Wildlife Service Lead Region: R4 - Southeast

NatureServe Global Conservation Status Factors

Range Extent Comments: Monroe County, Florida on Upper and Lower Matecumbe Keys, Key Largo, Plantation Key, Long Key, Umbrella Key, Key West. Cuba near Havana and Matanzas.

Number of Occurrences: 6 - 20
Number of Occurrences Comments: In the United States, approximately 7 occurrences are believed extant, with one additional occurrence ranked "failed to find" (last seen in 1975, searched for and not found in 2005) and one other occurrence ranked historical. Number of occurrences in Cuba unknown.

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: Rare throughout range and subject to collection and habitat destruction. Housing developments have exterminated most populations on the Matecumbe Keys. Canopy closure, a pathogen, and increased soil salinity from storm surges and/or sea level rise have been hypothesized as causes for declines observed since the mid-1990s (Goodman et al. 2009). A study was conducted in which sites on the west side (higher mortality) and east side (lower mortality) of one lower Key were compared; the higher mortality (west) side was found to be lower in elevation, to have significantly higher soil salinity, and to have 17% less canopy cover than the lower mortality (east) side (Goodman et al. 2009). The authors believe that "in the lower Keys, increased soil salinity coupled with impacts from herbivory and poaching have likely contributed to Pilosocereus demise" (Goodman et al. 2009). Salinity impacts are predicted to worsen as climate change proceeds, especially given that the species is restricted to rare, fragmented low elevation island habitats where there is little or no connection to higher ground (Goodman et al. 2009).

Short-term Trend: Decline of >70%
Short-term Trend Comments: In eight surveyed sites in the Florida Keys, P. robinii lost approximately 81% of plants and 88% of stems between 1994 and 2007 (Goodman et al. 2009).

Other NatureServe Conservation Status Information

Distribution
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Global Range: Monroe County, Florida on Upper and Lower Matecumbe Keys, Key Largo, Plantation Key, Long Key, Umbrella Key, Key West. Cuba near Havana and Matanzas.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States FL

Range Map
No map available.

National Distribution Outside of U.S. & Canada: Cuba

U.S. Distribution by County Help
State County Name (FIPS Code)
FL Monroe (12087)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
03 Florida Bay-Florida Keys (03090203)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A tree cactus with a distinct, erect trunk, up to 9 m tall, and few to many erect branches. The stems are blue-green, spiny, cylindrical, 8-10 cm thick. Blooms in April. The flowers are sparse, small (< 6 cm), and are borne on the ends of upper branches. Sepals are numerous and overlapping. Petals shade from green or purplish in the outer whorls to white in the center whorls. They open in the late afternoon and smell of garlic. Fruits are reddish, flattened spheres, 3-4 cm thick.
Terrestrial Habitat(s): Forest - Hardwood, Forest/Woodland, Shrubland/chaparral
Habitat Comments: Tropical hardwood hammocks occurring on limestone. Also in cactus hammock/thorn scrub habitats and in sandy soils in thickets just above high tide levels. Soils typically consist of a layer of partially decomposed organic material over a limestone substrate.
Economic Attributes Not yet assessed
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Management Summary Not yet assessed
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Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 18Jun1997
NatureServe Conservation Status Factors Author: L. Chafin, rev. K. Gravuer (2009)

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

References
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  • ADAMS, RALPH M. AND ALEXANDRO LIMA. 1994. NATURAL HISTORY OF THE FLORIDA KEYS TREE CACTUS, PILOSOCEREUS ROBINII. UNPUBLISHED REPORT PREPARED FOR THE U.S. FISH AND WILDLIFE SERVICE. +400 pp.

  • Austin, D. F. 1984. Resume of the Florida taxa of Cereus (Cactaceae). Florida Scientist 47: 68-72.

  • Borhidi, A. 1991. Phytogeography and Vegetation Ecology of Cuba. Akademiai Kiado, Budapest. 857 pp.

  • DISTRIBUTION AND ABUNDANCE OF PILOSOCEREUS ROBINII (LEMAIRE) BYLES AND ROWLEY IN THE FLORIDA KEYS. 1993. BRADLEYA, 14:57-62.

  • Goodman, J., J. Maschinski, J. Roncal, P. Hughes, and J. McAuliffe. 2009. Climate change threatens endangered key tree cactus (Pilosocereus robinii) in the Florida Keys, USA. Presentation at Ecological Society of America 2009 Annual Meeting, Albequerque, NM, 2-7 August. Abstract only. Available: http://eco.confex.com/eco/2009/techprogram/P19008.HTM (Accessed 2009)

  • Goodman, J., J. Maschinski, P. Hughes, J. McAuliffe, J. Roncal, D. Powell, and L. O'reilly Sternberg. 2012. Differential response to soil salinity in endangered Key Tree Cactus: implications for survival in a changing climate. PLoS ONE 7(3): e32528.

  • Hunt, D., ed. 2006a. The New Cactus Lexicon. dh books. The Manse, Chapel Lane, England. 373 pp.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • SMALL, J.K. 1917. THE TREE CACTI OF THE FLORIDA KEYS. JOURNAL OF THE NEW YORK BOTANICAL GARDEN 18(213): 199-203.

  • SMALL, J.K. 1917. THE TREE CACTI OF THE FLORIDA KEYS. JOURNAL OF THE NEW YORK BOTANICAL GARDEN. 18(213): 199-203.

  • U. S. FISH AND WILDLIFE SERVICE. 1985. FLORIDA KEY DEER RECOVERY PLAN. U. S. FISH AND WILDLIFE SERVICE, ATLANTA, GA. 46 PP.

  • U.S. FISH AND WILDLIFE SERVICE. 1984. FINAL RULE TO DETERMINE CEREUS ROBINII (KEY TREE CACTUS) TO BE AN ENDANGERED SPECIES. FEDERAL REGISTER 49(149):29234-29237.

  • U.S. FISH AND WILDLIFE SERVICE. 1984. FINAL RULE TO DETERMINE CEREUS ROBINII (KEY TREE CACTUS) TO BE AN ENDANGERED SPECIES. FEDERAL REGISTER 49(149):29234-29237.

  • U.S. Fish and Wildlife Service (USFWS). 2010. Key tree-cactus (Pilosocereus robinii) 5-Year Review: Summary and Evaluation. South Florida Ecological Services Field Office, Vero Beach, Florida. August 2010. Online. Available: http://ecos.fws.gov/docs/five_year_review/doc3278.pdf (Accessed 2012).

  • U.S. Fish and Wildlife Service. 1986. Key Tree-cactus Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, Georgia. 28 pp.

  • U.S. Fish and Wildlife Service. 1986. Key Tree-cactus Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, Georgia. 28 pp.

  • WARD, D.B. (ED). 1979. RARE AND ENDANGERED BIOTA OF FLORIDA, VOLUME 5: PLANTS. UNIVERSITY PRESSES OF FLORIDA, GAINESVILLE.

  • WEINER, A.H. 1979. THE HARDWOOD HAMMOCKS OF THE FLORIDA KEYS: AN ECOLOGICAL STUDY. NATIONAL AUDUBON SOCIETY & FLORIDA KEYS LAND TRUST. TWO COPIES.

  • Ward, D.B., ed. 1979. Rare and endangered biota of Florida. Vol. 5: Plants. Univ. Presses of Florida, Gainesville.

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