The Continuing Population Decline of Torreya Taxifolia Arn

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Torreya taxifolia Arn.

Florida Torreya

Federal Protection: Listed Endangered

State Protection: Endangered

Global Rank: G1

State Rank: S1

Element Locations Tracked in Biotics: Yes

SWAP High Priority Species (SGCN): Yes

Element Occurrences (EOs) in Georgia: 6

Habitat Summary for element in Georgia: Rich ravines in extreme Southwest Georgia


Description

Evergreen, coniferous tree with whorled branches and shredding bark, formerly to 60 feet (18 meters) tall, now seen in the wild only as stump sprouts of trees top-killed by a lethal fungus, usually less than 15 feet (5 meters) tall. The needles are 1 - 1.6 inches (2.4 - 4 cm) long, flat, stiff, and very sharply pointed; bright green above and light green below with two gray stripes (of stomates) paralleling the midvein; the needles are held in two parallel rows along the twig, spreading rigidly in a single plane away from the twig. Both the twigs and needles emit a strong, unpleasant odor when crushed. Female and male cones are on separate plants (they are now rarely seen in the wild because maturing trees are killed by a fungal blight before they can reproduce).Female cones are 1 - 1.2 inch (2.5 - 3.2 cm) long, green, oval, smooth, berry-like, produced singly at the base of a few needles on the current season's twigs.Male cones are less than 0.4 inch (1 cm) long, tan, scaly, and held in rows along the previous season's twigs at the base of the needles.

Similar Species

No other native tree or shrub in Georgia has long, stiff, sharp, evergreen, odorous needles. China Fir (Cunninghamia lanceolata), an introduced ornamental tree frequently seen at old home sites, has similar bark and needles but the needles are spirally arranged on the twigs and lack the unpleasant odor; old brown needles usually cling to its twigs. It has not escaped into natural habitats.

Related Rare Species

Florida Yew (Taxus floridana) is also in the Yew family; it occurs in ravines in north Florida, often near Florida Torreya, but has never been found in Georgia. It is a small tree or shrub with purplish-brown, scaly bark and soft, aromatic needles that have pale stripes below. For more information, see: http://beta.floranorthamerica.org/Taxus_floridana

Habitat

Rich, deciduous forests with Beech and Southern Magnolia on mid-slopes of ravines and steepheads along the east side of Lake Seminole in Georgia and the Apalachicola River in Florida.

Life History

Before the advent of the blight in the 1950s, Florida Torreya trees lived to be many years old and became sexually mature at around 20 years. Florida Torreya is dioecious – female cones and male cones are produced on separate plants in the spring – and pollen is dispersed by the wind. Each berry-like female cone initially contains 2 seeds but only 1 matures; seeds take 2 years to mature. Cones are no longer seen in the wild due because the blight kills the trees before they reach reproductive age.  Florida Torreya sends up sprouts from the roots, stump, and root crown that grow for several years before being killed by the blight; the ability to sprout has allowed the species to persist in spite of the blight and may allow for recovery if a treatment is found for the fungal blight.

Survey Recommendations

Florida Torreya is evergreen and recognizable all year, but is more easily seen during winter when leaves are off the surrounding deciduous trees. Currently, trees rarely exceed 10 feet tall and are most often seen as small, shrub-like plants.

Range

Endemic to a small area in southwest Georgia and adjacent areas along the Apalachicola River in north Florida.

Threats

Logging, conversion of habitat to pine plantations, fungal blight, extreme hurricane events, diversion of resources to uninformed and unauthorized assisted migration efforts.

Georgia Conservation Status

Florida Torreya is nearly extinct in the wild due to fungal blight and destruction of habitat; fewer than 1% of the original populations are extant. Several populations occur on conservation lands, but they are vulnerable to blight. Many of the few remaining trees were wiped out by Hurricane Michael in 2018. Florida Torreya is the focus of considerable conservation efforts by private and governmental conservation agencies and universities and many trees are maintained ex situ in botanical gardens and preserves. Florida Torreya is ranked S1 by the Georgia Department of Natural Resources, indicating that it is critically endangered in Georgia. It is listed as Endangered by the State of Georgia and the U.S. Fish and Wildlife Service.

Conservation Management Recommendations

Support and fund coordinated ex situ conservation at botanical gardens and other preserves. Continue monitoring wild populations for blight. Avoid logging and other disturbances in ravine forests. Purchase or protect with conservation easements all remaining populations on private lands. Fund research toward identifying and treating the fungal blight. Discourage attempts at assisted migration unless carried out by authorized agencies. Address climate change and its impact on native and rare plant species.

References

Alfieri, S.A., Jr., A.P. Martinez, and C. Wehlburg. 1967. Stem and needle blight of Florida Torreya. Proceedings of Florida State Horticultural Society 80: 428-431. https://journals.flvc.org/fshs/article/view/100338/96306

Chafin, L.G. 2007. Field guide to the rare plants of Georgia. State Botanical Garden of Georgia and University of Georgia Press, Athens.

Chapman, D. 2019. Saving the Florida Torreya: One goal, two schools of thought on preserving the rare, endangered tree. U.S. Fish and Wildlife Service, Atlanta, Georgia. https://www.fws.gov/southeast/articles/saving-the-florida-torreya/

Godfrey, R.K. 1988. Trees, shrubs, and woody vines of northern Florida and adjacent Georgia and Alabama. University of Georgia Press, Athens.

GADNR. 2020. Element occurrence records for Torreya taxifolia. Georgia Department of Natural Resources, Wildlife Resources Division, Social Circle, Georgia.

Groves, M. and R. Determann. 2003. Update on the recovery of Torreya taxifolia at the Atlanta Botanical Garden, Georgia, USA. Acta Horticulturae (ISHS) 615: 429-431. https://www.actahort.org/books/615/615_49.htm

Hils, M. 1993. Torreya taxifolia species account. Flora of North America, Vol. 2. Oxford University Press, New York. http://beta.floranorthamerica.org/Torreya_taxifolia

Mola, J.M., J.M. Varner, and T. Spector. 2014. Altered community flammability in Florida's Apalachicola Ravines and implications for the persistence of the endangered conifer Torreya taxifolia. PLoS One 9(8): e103933. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4118970/

NatureServe. 2020. Torreya taxifolia species account. NatureServe Explorer. NatureServe, Arlington, Virginia. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.137133/Torreya_taxifolia

Patrick, T.S., J.R. Allison, and G.A. Krakow. 1995. Protected plants of Georgia. Georgia Department of Natural Resources, Natural Heritage Program, Social Circle.

Schwartz, M.W. 1993. Allozyme variation of the endangered Florida torreya (Torreya taxifolia). Canadian Journal of Forest Research 23: 2598-2602. https://www.nrcresearchpress.com/doi/abs/10.1139/x93-322

Schwartz, M.W. and S.M. Hermann. 1993. Continuing population decline of Torreya taxifolia Arn. Bulletin of the Torrey Botanical Club 120: 275-286. https://www.jstor.org/stable/2996992?seq=1#metadata_info_tab_contents

Schwartz, M.W. and S.M. Hermann. 1993. Population ecology of Torreya taxifolia: habitat evaluation, fire ecology, and genetic variability. Non-game Wildlife Program, Florida Game and Freshwater Fish Commission, Tallahassee. https://tinyurl.com/y9e976c7

Schwartz, M.W., S.M. Hermann, and C. Vogel. 1995. The catastrophic loss of Torreya taxifolia: assessing environmental induction of disease hypotheses. Ecological Applications 5(2): 501-516. https://www.jstor.org/stable/1942039?seq=1#metadata_info_tab_contents

Schwartz, M.W. and S.M. Hermann. 1999. Is slow growth of the endangered Torreya taxifolia (Arn.) normal? Journal of the Torrey Botanical Society, Vol. 126(4): 307-312. https://www.jstor.org/stable/2997314?seq=1#metadata_info_tab_contents

Schwartz, M.W., S.M. Hermann, and P.J. Van Mantgem. 2000. Population persistence in Florida Torreya: comparing modeled projections of a declining coniferous tree. Conservation Biology 14(4): 1023-1033. https://conbio.onlinelibrary.wiley.com/doi/full/10.1046/j.1523-1739.2000.98393.x

Schwartz, M. W. 2005. Conservationists should not move Torreya taxifolia. Wild Earth 14:72-79.  https://www.esf.edu/efb/lomolino/courses/MammalDiversity/Disc5/C.pdf

Smith, J.A., K. O'Donnell, L.L. Mount, K. Shin, K. Peacock, et al. 2011. A novel Fusarium species causes a canker disease of the critically endangered conifer, Torreya taxifolia. Plant Disease 95: 633–639. https://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-10-10-0703

Smith, J.A. and A. Trulock. 2018. The decline of Florida Torreya, an endemic conifer on the edge of extinction. Institute of Food and Agricultural Sciences, University of Florida. https://edis.ifas.ufl.edu/fr338#FOOTNOTE_1

USFWS. 2018. Florida Torreya (Torreya taxifolia) species profile and related documents. U.S. Fish and Wildlife Service, Atlanta, Georgia. https://ecos.fws.gov/ecp0/profile/speciesProfile?sId=5391

Weakley, A.S. 2015. Flora of the southern and mid-Atlantic States. University of North Carolina Herbarium, University of North Carolina, Chapel Hill. http://www.herbarium.unc.edu/flora.htm

Authors of Account

Linda G. Chafin

Date Compiled or Updated

L. Chafin, Jan. 2009: original account

K. Owers, Feb. 2010: added pictures

L. Chafin, May 2020: updated original account

barnettetivere.blogspot.com

Source: https://georgiabiodiversity.org/natels/profile?es_id=18410

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