First U.S. vascular plant extirpation linked to sea level rise? Pilosocereus millspaughii (Cactaceae) in the Florida Keys, U.S.A.


  • Jennifer Possley Fairchild Tropical Botanic Garden
  • James J. Lange Fairchild Tropical Botanic Garden
  • Alan R. Franck Florida Museum of Natural History
  • George D. Gann The Institute for Regional Conservation
  • Trudy Wilson Florida Department of Environmental Protection
  • Susan Kolterman Florida Department of Environmental Protection
  • Janice Duquesnel Florida Department of Environmental Protection
  • Joseph O’Brien USDA Forest Service, Southern Research Station



Cacti, at-risk species, climate change, extirpation, ex situ conservation, endemism


The global biodiversity crisis affects species across all continents and taxonomic groups. Direct destruction of species and habitats has been a primary driver of declines, though climate change and associated sea level rise are expected to accelerate loss. The flora of low-lying, relatively isolated islands is especially threatened when high species richness intersects with vulnerability to sea level rise. The Florida Keys represent a hotspot for cactus diversity in the eastern United States, with eight species recognized, three of which are endemic to the islands. Though not endemic to the islands, the Key Largo tree cactus (Pilosocereus millspaughii) was known in the United States from only a single population in the Florida Keys. Its decline and imminent extirpation correspond with rising sea levels in the region. The other cacti in the region, and all rare plants in the Florida Keys, are threatened with a similar fate.


ADAMS, R.M. & A.N. LIMA. 1994. The natural history of the Florida Keys tree cactus Pilosocereus robinii. Report to US Fish and Wildlife Service, U.S.A.

AUSTIN, D.F., D.M. BINNINGER, & D.J. PINKAVA. 1998. Uniqueness of the endangered Florida semaphore cactus (Opuntia corallicola). Sida 18(2):527–534.

BARBOUR, D.B. & S.R. HUMPHREY. 1982. Status and habitat of the Key Largo woodrat and cotton mouse (Neotoma floridana smalli and Peromyscus gossypinus allapaticola) J. Mammal. 63(1):144–148.

BELLARD, C., C. LECLERC, & F. COURCHAMP. 2013. Impact of sea level rise on the 10 insular biodiversity hotspots. Glob. Ecol. Biogeogr. 23(2):203–212.

BENEDICT, L., B. GLAZER, S. TRAXLER, C. BERGH, B. STYS, & J. EVANS. 2018. Florida Keys case study on incorporating climate change considerations into conservation planning and actions for threatened and endangered species. Project report for USFWS Cooperative Agreement F16AC01213. 152 pgs.

BIGLER, C., D. KULAKOWSKI, & T.T. VEBLEN. 2005. Multiple disturbance interactions and drought influence fire severity in Rocky Mountain subalpine forests. Ecology 86:3018–3029.

BRADLEY, K.A. & S.W. WOODMANSEE. 2002. A significant new population of the rare semaphore pricklypear cactus, Opuntia corallicola (Cac-taceae). Sida 20(2):809–811.

BRADLEY, K.A. & S. SAHA. 2009. Post-hurricane responses of rare plant species and vegetation of pine rocklands in the Lower Florida Keys. Report to US Fish and Wildlife Service, National Key Deer Refuge. The Institute for Regional Conservation, Delray Beach, FL, U.S.A.

BRITTON, N.L. & J.N. ROSE. 1923. The Cactaceae. Volume 4. Carnegie Institution of Washington, DC, U.S.A.

CBD (CONVENTION ON BIOLOGICAL DIVERSITY). 2022. Fifteenth meeting of the Conference of the Parties to the Convention on Biological Diversity (Part Two). Decision 4 - Kunming-Montreal Global Biodiversity Framework.

CPC (CENTER FOR PLANT CONSERVATION). 2019. CPC best plant conservation practices to support species survival in the wild. Center for Plant Conservation, Escondido, CA, U.S.A.

DANIELS, J.C. 2009. Cooperative conservation efforts to help recover an endangered south Florida butterfly. Insect. Conserv. & Divers. 2(1):62–64.

FAC (FLORIDA ADMINISTRATIVE CODE). 1998. Plants in the Preservation of Native Flora of Florida Act. Chapter 5B–40 amended.

FRANCK, A.R. 2012. Synopsis of Harrisia including a newly described species, several typifications, new synonyms, and a key to species. Haseltonia 18:95–104.

FRANCK, A.R., D. BARRIOS, K. CAMPBELL, J. LANGE, B. PEGUERO, E. SANTIAGO-VALENTIN, Z. RIGERSZKI, J. HAAKONSSON, G.D. GANN, W. CINEA, N. HOWE, J. ST JOHN, J.S. MORENO, & C.A. CLARK. 2019. Revision of Pilosocereus (Cactaceae) in the Caribbean and northern Andean region. Phytotaxa 411(3):129–182.

GANN, G.D., K.A. BRADLEY, & S.W. WOODMANSEE. 2002. Rare plants of South Florida: their history, conservation, and restoration. Institute for Regional Conservation, Miami, FL, U.S.A.

GANN, G.D., L.B. TROTTA, & COLLABORATORS. 2001–2023. Floristic Inventory of South Florida Database [web application]. The Institute for Regional Conservation. Delray Beach, FL, U.S.A. Available at Accessed May 2023).

GOETTSCH, B., C. HILTON-TAYLOR, G. CRUZ-PIÑÓN, ET AL. 2015. High proportion of cactus species threatened with extinction. Nature Pl. 1, 15142.

GOODMAN, J., J. MASCHINSKI, P. HUGHES, J. MCAULIFFE, J. RONCAL, D. POWELL, ET AL. 2012. Differential response to soil salinity in endangered Key tree cactus: implications for survival in a changing climate. PLoS ONE 7(3):e32528.

GUERRANT, E.O., K. HAVENS, & M. MAUNDER, EDS. 2004. Ex situ plant conservation: supporting species survival in the wild. Island Press, Washington, DC, U.S.A.

HOEGH-GOLDBERG, H. 2010. Climate change and the Florida Keys. National Atmospheric and Oceanic Administration report. Available online:

HOFFMEISTER, J.E. 1974. Land from the sea: The geologic story of South Florida. University of Miami Press, Coral Gables, Florida, U.S.A.

IPBES (INTERGOVERNMENTAL PANEL ON BIODIVERSITY AND ECOSYSTEM SERVICES). 2019. Global assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. Brondízio, E.S., J. Settele, S. Díaz, & H.T. Ngo, eds. IPBES secretariat, Bonn, Germany.

IPCC (INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE). 2018. Summary for Policymakers. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte V., P. Zhai, H-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, & T. Waterfield, Eds.].

IUCN/SSC. 2013. Guidelines for reintroductions and other conservation translocations. Version 1.0. IUCN Species Survival Commission, Gland, Switzerland.

IUCN/SSC. 2014. Guidelines on the use of ex situ management for species conservation. Version 2.0. IUCN Species Survival Commission, Gland, Switzerland.

KARTESZ, J.T. 2015. The Biota of North America Program (BONAP). North American Plant Atlas. ( Chapel Hill, NC, U.S.A. [maps generated from Kartesz, JT 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].

KNAPP, W.M., A. FRANCES, R. NOSS, R.F.C. NACZI, A. WEAKLEY, G.D. GANN, B.G. BALDWIN, J. MILLER, P. MCINTYRE, B.D. MISHLER, G. MOORE, R.G. OLMSTEAD, A. STRONG, K. KENNEDY, B. HEIDEL, & D. GLUESENKAMP. 2021. Vascular plant extinction in the continental United States and Canada. Conserv. Biol. 35(1):360–368.

KOROTKOVA, N., D. AQUINO, S. ARIAS, U. EGGLI, A. FRANCK, C. GÓMEZ-HINOSTROSA, P.C. GUERRERO, H.M. HERNÁNDEZ, A. KOHLBECKER, M. KÖHLER, K. LUTHER, L.C. MAJURE, A. MÜLLER, D. METZING, R. NYFFELER, D. SÁNCHEZ, B. SCHLUMPBERGER, & W.G. BERENDSOHN. 2021. Cactaceae at – a dynamic online species-level taxonomic backbone for the family. Willdenowia 51(2):251–270.

LONG, R.W. & O. LAKELA. 1971. A flora of tropical Florida. Univ Miami Press, Coral Gables, FL, U.S.A.

MAJURE, L.C., D.E. SOLTIS, P.S. SOLTIS, & W.S. JUDD. 2012. Cytogeography of the Humifusa clade of Opuntia s.s. (Cactaceae: Opuntioideae): Correlations with geographic distributions and morphological differentiation of a polyploid complex. Comp Cytogenet 6:53–77.

MAJURE, L.C., D.E. SOLTIS, P.S. SOLTIS, ET AL. 2013. A case of mistaken identity, Opuntia abjecta, long-lost in synonymy under the Caribbean species, O. triacantha, and a reassessment of the enigmatic O. cubensis. Brittonia 66:118–130.

MAJURE, L.C., W.S. JUDD, D.E. SOLTIS, & P.S. SOLTIS. 2017. Taxonomic revision of the Opuntia humifusa complex (Opuntieae: Cactaceae) of the eastern United States. Phytotaxa 290(1):1–65.

MASCHINSKI, J., M.S. ROSS, H. LIU, J.J. O’BRIEN, E.J. VON WETTBERG, & K.E. HASKINS. 2011. Sinking ships: conservation options for endemic taxa threatened by sea level rise. Clim. Change. 107:147–167

MAZZEI, P. 2019. 82 days underwater: The tide is high, but they’re holding on. The New York Times 11/24/19.

NATIONAL WEATHER SERVICE (NWS). 2023a. Tropical cyclones of the 2000s. Available at Accessed March 2023.

NATIONAL WEATHER SERVICE (NWS). 2023b. Most intense Florida Keys tropical cyclones. Available at Accessed March 2023.

NATURESERVE. 2023a. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia, U.S.A. Available at Accessed January 2024.

NATURESERVE. 2023b. Biodiversity in Focus: United States Edition. NatureServe, Arlington, Virginia, U.S.A. Available at Accessed December 2023.

NOAA (NATIONAL OCEANOGRAPHIC AND ATMOSPHERIC ADMINISTRATION). 2023 Sea level trends for Vaca Key, Florida (Station 8723970). Available at Accessed June 2023.

NOSS, R. 2011. Between the devil and the deep blue sea: Florida’s unenviable position with respect to sea level rise. Clim. Change. 107(1):1–16.

PILLET, M., B. GOETTSCH, C. MEROW, B. MAITNER, X. FENG, P.R. ROEHRDANZ, & B.J. ENQUIST. 2022. Elevated extinction risk of cacti under climate change. Nat. Pl. 8(4):366–372.

POSSLEY, J., J. DUQUESNEL, & V. MCDONOUGH. 2022. Thirty years of conserving Sargent’s cherry palm (Pseudophoenix sargentii) in the Florida Keys. Palms 65(4):165–176.

POSSLEY, J. & J. MASCHINSKI. 2023. Long-term conservation efforts for the endangered Key tree cactus. Case study in: F Singarayer, P Gibson-Roy, K Dixon, L Broadhurst, eds. Ecological Restoration: Moving Forward Using Lessons Learned. Springer Nature, Switzerland.

REECE. J.S., R.F. NOSS, J. OETTING, T. HOCTOR, & M .VOLK. 2013. A vulnerability assessment of 300 species in Florida: threats from sea level rise, land use, and climate change. PLoS ONE 8(11):e80658.

ROSS, M.S., J.J. O'BRIEN, & L.J. FLYNN. 1992. Ecological site classification of Florida Keys terrestrial habitats. Biotropica 24:488–502.

ROSS, M.S., J.J. O’BRIEN, & L. DA SILVEIRA LOBO STERNBERG. 1994. Sea level rise and the reduction in pine forests in the Florida Keys. Ecol. Appl. 4:144–156.

ROSS, M.S., J.J. O’BRIEN, R.G. FORD, ET AL. 2009. Disturbance and the rising tide: the challenge of biodiversity management on low-island ecosystems. Front. Ecol. Environ. 7:471–478.

SALAZAR, A., J. MASCHINSKI, & D. POWELL. 2013. Ex-situ seed conservation of endangered key tree cactus (Pilosocereus robinii). J. Biodivers. Endanger. Species 1:111.

SEDDON, P.J., W.M. STRAUSS, & J. INNES. 2012. Animal translocations: what are they and why do we do them? In: Ewen, J.G., D.P. Armstrong, K.A. Parker, et al., eds. Reintroduction biology: integrating science and management. Wiley Blackwell, West Sussex, UK.

SMALL, J.K. 1913. Flora of the Florida Keys: Being descriptions of the seed-plants growing naturally on the islands of the Florida reef from Virginia Key to Dry Tortugas. Press of the New Era Printing Company, Lancaster, PA, U.S.A.

SMALL, J.K.1917. The tree cacti of the Florida Keys. J. New York Bot. Gard. 18:198–203.

SMALL, J.K. 1919. The prickly pears of Florida. J. New York Bot. Gard. 20: 21–39.

SMALL, J.K. 1933. Manual of the southeastern flora. Univ. of North Carolina Press, Chapel Hill, NC, U.S.A.

STILING, P. A. ROSSI, & D. GORDON. 2000. The difficulties of single factor thinking in restoration: replanting a rare cactus in the Florida Keys. Biol. Conserv. 94:327–333.

STILING, P. & D. MOON. 2001. Protecting rare Florida cacti from attack by the exotic cactus moth, Cactoblastis cactorum (Lepidoptera : Pyralidae). Florida Entomol. 84:506–509.

STILING, P. 2010. Death and decline of a rare cactus in Florida. Castanea 75:190–197.

SUBEDI, S.C., S.C. WALLS, W.J. BARICHIVICH, R. BOYLES, M.S. ROSS, J.A. HOGAN, & J.A. TUPY. 2022. Future changes in habitat availability for two specialist snake species in the imperiled rocklands of South Florida, USA. Conserv. Sci. Pract. 4(10):e12802.

Sweet, W.V., B.D. Hamlington, R.E. Kopp, C.P. Weaver, P.L. Barnard, D. Bekaert, W. Brooks, M. Craghan, G. Dusek, T. Frederikse, G. Garner, A.S. Genz, J.P. Krasting, E. Larour, D. Marcy, J.J. Marra, J. Obeysekera, M. Osler, M. Pendleton, D. Roman, L. Schmied, W. Veatch, K.D. White, & C. Zuzak. 2022. Global and regional sea level rise scenarios for the United States: updated mean projections and extreme water level probabilities along U.S. coastlines. NOAA Technical Report NOS 01. National Oceanic and Atmospheric Administration, National Ocean Service, Silver Spring, MD, 111 pp. Available at

TYE, M.R., E.S. MENGES, C. WEEKLEY, P.F. QUINTANA-ASCENCIO, & R. SALGUERO-GÓMEZ. 2016. A demographic ménage à trois: interactions between disturbances both amplify and dampen population dynamics of an endemic plant. J. Ecol. 104(6):1778–1788.

USFWS (US FISH AND WILDLIFE SERVICE). 1984. Final rule to determine Cereus robinii (Key tree-cactus) to be endangered species. 78 FR 63795 63821.

USFWS (US FISH AND WILDLIFE SERVICE). 2013. Determination of endangered status for Chromolaena frustrata (Cape Sable thoroughwort), Consolea corallicola (Florida semaphore cactus), and Harrisia aboriginum (Aboriginal prickly-apple); Final Rule. 78 FR 63795 63821.

WALTERS, J.R., S.R. DERRICKSON, D.M. FRY, S.M. HAIG, J.M. MARZLUFF, & J.M. WUNDERLE. 2010. Status of the California condor (Gymnogyps califor-nianus) and efforts to achieve its recovery. Auk 127(4):969–1001.

WENDELBERGER. K.S., M.Q.N. FELLOWS, & J. MASCHINSKI. 2008. Rescue and restoration: experimental translocation of Amorpha herbacea Walter var. crenulata (Rybd.) Isley into a novel urban habitat. Restor. Ecol. 16(4):542–552.

WOODMANSEE, S., M. NELSON, S. REUTLING, & M. CHANDLER. 2022. Key West Botanical Garden Society Florida Department of Agriculture and Consumer Services Grant # 027842 2021-2022 Florida Keys Rare Plant Conservation Program Final Report.

WUNDERLIN, R.P. & B.F. HANSEN. 2011. Guide to the vascular plants of Florida, 3rd ed. University Press of Florida, Tampa, U.S.A.

WUNDERLIN, R.P., B.F. HANSEN, A.R. FRANCK, & F.B. ESSIG. 2023. Atlas of Florida plants ( [S.M. Landry and K.N. Campbell (application development), USF Water Institute.] Institute for Systematic Botany, University of South Florida, Tampa, U.S.A.




How to Cite

Possley, J., Lange, J. J., Franck, A. R., Gann, G. D., Wilson, T., Kolterman, S., Duquesnel, J., & O’Brien, J. (2024). First U.S. vascular plant extirpation linked to sea level rise? Pilosocereus millspaughii (Cactaceae) in the Florida Keys, U.S.A. Journal of the Botanical Research Institute of Texas, 18(1), 211–223.

Most read articles by the same author(s)