Conservation Action Plan



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Conservation Action Plan

Lantana canescens


Species Name: Lantana canescens Kunth

Common Name(s): Hammock shrubverbena

Synonym(s): Lantana microcephala A.Rich and Goniostachyum citrosum Small are the most common synonyms still in use today. Others include Camara canescens (Kunth)Kuntze, Camara microcephala (A. Rich.)Kuntze, Lantana canescens Kunth forma grandifolia Moldenke, Lantana canescens Kunth forma parvifolia Moldenke, Lantana canescens Kunth forma pluripedunculata Moldenke, Lantana canescens Kunth var. integrifolia Moldenke, Lantana citrosa (Small)Moldenke, Lantana lamiifolia Otto &A.Dietr. and Lippia pallescens Benth. (Wunderlin & Hansen 2003).

Family: Verbenaceae

Species/taxon description: Shrub to 6 m, with gray or white 4-angled stems. Leaves to 6.5 cm long, opposite, simple, lanceolate to elliptic-lanceolate, densely hairy on both surfaces, with prominent secondary veins, shallowly toothed margins, pointed tips, and wedge-shaped bases. Flowers white and tubular with 5 spreading, irregular lobes, in flattened clusters at the ends of long stalks arising in the angle of leaf and stem. Fruit a spherical nutlet to 1.5 mm wide, one-seeded, hard, dry (modified from Chafin 2000 and Coile 2000). In south Florida, L. canescens often has few leaves, which sometimes senesce during the dry season.
Legal Status: Florida endangered

Biogeographic status: Native
Prepared by: Jennifer Possley, Research Dept, Fairchild Tropical Botanic Garden

Last Updated: 4 May 2004

J. Possley

Background and Current Status




Range-wide distribution – past and present



Florida {CONFIDENTIAL}
World: Florida, southern Texas, Cuba, West Indies, Mexico, Central America, South America (including Argentina, Brazil, Colombia and Ecuador)


Population and reproductive biology/life history



Annual/Perennial: Perennial

Habit: Shrub

Average life span: Unknown (but Fairchild monitoring will shed some light on this by the 2007 report of Biological Monitoring for Miami-Dade County lands).

Flowering period: All year, though Fairchild monitoring has shown January seems to be the best month

Fruiting period: All year, though Fairchild monitoring has shown January seems to be the best month

Annual variability in flowering: Possibly greatest in winter.

Growth Period: Unknown

Dispersal: No dispersers observed, and the population distribution does not indicate significant dispersal, as seedlings have been found only very near the parent population. In the Verbenaceae, nutlets are usually dispersed gradually by wind or mechanical contact, though birds or water may also disperse the fruit (Judd et al. 1999).

Pollination: Specific pollinators are unknown, but like all Verbenaceae, Lantana spp. are likely to be pollinated by nectar-gathering bees, wasps, and flies (Judd et al. 1999). For example, Lantana camara L. is pollinated by bees and butterflies (Arenas No Date).

Seed Maturation Period: Unknown



Seed Production: Seed production on the order of 10-50 seeds per plant has been observed in the wild and in Fairchild’s nursery.

Seed Viability: Unknown, but a few seeds have recruited in pots of parent plants at the Fairchild nursery.

Regularity of Establishment: Appears to be low and not very regular.

Germination Requirements: Unknown

Establishment Requirements: Unknown

Population Size: {CONFIDENTIAL}

Number and Distribution of Populations: {CONFIDENTIAL}

Habitat description and ecology



Type: ROCKLAND HAMMOCK/PINE ROCKLAND ECOTONE.
Physical Features:

Soil: Limestone covered by little or no organic matter.

Elevation: The Miami rock ridge ranges from 7-4 m above sea level (Snyder et al., 1990).

Aspect: Unknown

Slope: The three most recently extant populations grow/grew on level substrate.

Moisture: Low

Light: Medium-high
Biotic Features:

Community: Associated shrubs and trees include Koanophyllon villosum, Guettarda scabra, and Metopium toxiferum. Pinus elliottii var. densa can be present in the canopy.

Interactions:

Competition: Unknown

Mutualism: Unknown

Parasitism: Parasitism by Cassytha filiformis L. is problematic in a

portion of the remaining population, with the vine becoming very dense in

some places. This vine is removed during annual monitoring by Fairchild.

Other: Unknown

Animal use: Unknown

Natural Disturbance:

Fire: Fire is an absolute necessity to maintain the ecotone in which L. canescens naturally grows. Direct ecological effects of fire on L. canescens are not known.

Hurricane: Hurricane activity may stimulate the growth of populations. Gann et al. (2002) noted a “substantial” population increase at one site [12] following Hurricane Andrew in 1992.

Slope Movement: Unknown

Small Scale (i.e. Animal Digging): Unknown

Temperature: Unknown

Protection and management



Summary: {CONFIDENTIAL}
Availability of source for outplanting: {CONFIDENTIAL}
Availability of habitat for outplanting: Currently, well-maintained pineland/hammock ecotone is almost non-existent in Miami-Dade County due to fire suppression and the practice of placing fire breaks on ecotones. There are only a handful of natural areas within the range of L. canescens that have pineland/hammock ecotone in any condition. Areas chosen for outplantings should include pineland/hammock ecotones with the greatest possibility of maintenance through fire and/or mechanical means.


Threats/limiting factors



Natural:

Herbivory: Unknown

Disease: Unknown

Predators: Unknown

Succession: Invasion by native hardwoods in the face of fire suppression is the single largest threat to the survival of extant populations of L. canescens. Hardwood invasion pushes ecotones back to boundaries such as roads, canals, and agricultural fields. Over time, the ecotone completely disappears, leaving only hammock.

Weed invasion: Weed invasion poses a serious threat to the remaining population of L. canescens [Site 12]. Several non-native plants are found nearby, with a substantial population of woodrose (Merremia tuberosa (L.) Rendle) being the most serious. Miami-Dade County Natural Areas Management is aware of this population, however, and keeps it in check. It cannot be completely eliminated because it encroaches from neighboring private property, where it is plentiful.

Fire: As described above, succession in the face of fire suppression is a lethal

threat to L. canescens. However, uncontrolled fire that burns too hot would also

be a major threat to this species. A careful controlled burn should be conducted

around the remaining population, not only to re-establish ecotonal habitat, but

also to ensure that a wildfire does not devastate it.

Genetic: Non-native Lantana camara L. is not known to hybridize with this species, but there is not information showing that hybridization would not occur. Given that both species are present in the same location, care should (and will) be taken to watch for hybrids while monitoring.

Anthropogenic


On site: At the site of the remaining L. canescens population, there is an individual growing in the right-of-way of the firebreak that is regularly mowed. However, park staff has been very obliging in protecting this individual, and have placed logs around it as a signal to mow around the plant. Several plants are also located adjacent to a plowed field where pole beans are grown. These individuals face a number of possible dangers including pesticide drift and plowing. While the field isn’t currently being plowed to the very edge, these plants are actually about 1.5 m outside of the park boundary and should not be considered protected.

Off site: Lack of public support and understanding regarding prescribed burning

is probably the largest off-site anthropogenic threat to this species’ survival in

south Florida. Other threats include large-scale hydrological alterations, and

pesticide spraying for mosquitoes may be a threat to the reproduction (i.e., insect

pollination) of this species.

Collaborators

Miami-Dade Natural Area Management

Miami-Dade County Park and Recreation


The Institute for Regional Conservation

Conservation measures and actions required



Research history: There appears to be no research published on this species in the state of Florida. Jennifer Possley of Fairchild monitors all remaining individual plants of this species on an annual basis (funding secured for 2002-2007), and collects information on phenology, size, and general health. One Brazilian phytochemical study comparing L. canescens and L. camara is posted on the Internet (www.adaltech.com.br). This study looked at the ethnomedical uses of each plant for colds and stomach ailments.
Significance/Potential for anthropogenic use: L. canescens shows some useful properties as medicine for colds and stomach ailments (www.adaltech.com.br). In addition, it would likely be of interest to native plant enthusiasts if it were to become available horticulturally.
Recovery objectives and criteria (when available): There are no federally established recovery goals or criteria for this species.
Management options:

Maintain the status quo: If management continues as it has thus far, the

remaining population of L. canescens in the United States will very likely be lost due to the effects of fire suppression.



Conduct manual hardwood removal: In Summer 2003, Cristina Rodriguez of

Miami-Dade Natural Areas Management had crews thin hardwoods 1-1.5 m from

the hammock edge in one natural area [Site 85] where the number of L. canescens had dropped precipitously in the previous 5-10 years (G. Gann, pers. comm.). One to two months after this treatment, George Gann of The Institute for Regional Conservation located a single plant in the thinned area that appeared to be resprouting from the base. However, by 2004, this plant had disappeared. If controlled burns are absolutely not possible, then most local managers and ecologists seem to agree that manual hardwood removal (such as was done at this site) is the next best thing, because it increases the amount of sunlight and bare soil that L. canescens appears to require. But as this case demonstrates, it may not be enough.

Conduct prescribed burns: Prescribed burning is the best way to maintain the

habitat that L. canescens needs. It will not only open up space and increase light,

but it will return nutrients to the rocky soil. Several successive burns will

probably be necessary to return ecotones to a more natural, pre-fire-suppression

and pre-fragmentation state. Burns MUST be continued across firebreaks to burn

into the hammock edge, which will probably be difficult in some areas and the

fire may need to be supplemented at first with hardwood removal.

Conduct outplantings: Prescribed burning along with outplantings are the ideal

way in which to begin the recovery of L. canescens in Miami-Dade County.

However, recovery will be possible only if (1) Fairchild first establishes an ex situ

collection containing duplicate clones of each in situ plant, (2) Natural Areas

Management is able to initiate prescribed burning in hammock/pine ecotones of

the southern rock ridge, and (3) managers can work with Fairchild to establish

outplanted populations in the areas where future burning is most likely to be

possible, this would be the ideal situation to begin recovery of this species in

Miami-Dade County.
Next Steps:


  1. Continue monitoring the extant population on at least an annual basis (Fairchild, with Natural Areas Management).

  2. Continue surveying for L. canescens in the two areas from where it was recently extirpated on a bi-annual basis (Fairchild, with Natural Areas Management).

  3. If L. canescens is rediscovered at an extirpated site, then collect cuttings as soon as possible to establish ex situ clones from that population, assuming plants are large enough (Fairchild).

  4. {CONFIDENTIAL}

  5. While it may not be feasible due, attempt to conduct careful controlled burns in pineland/hammock ecotone at all three sites where L. canescens has been most recently reported. This will necessitate burning into hammocks on the inside of firebreaks (Natural Areas Management).

  6. Conduct late spring or early summer outplantings of a portion of the ex situ clones into recently burned habitats that have the best chance of being maintained through controlled burns in the future (Fairchild).


References

Arenas, M. No Date. Honey bee foraging behavior on Lantana camara (Verbenaceae). University of Miami, Department of Biology. Paper accessed online at http://www.bio.miami.edu/oprograms/arenas.htm.


Chafin, L.G. 2000. Field guide to the rare plants of Florida. Florida Natural Areas Inventory, Tallahassee, Florida.
Coile, N.C. 2000. Notes on Florida’s endangered and threatened plants. Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Bureau of Entomology, Nematology and Plant Pathology. Contribution No. 38, 3rd Ed.
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.
Judd, W.S, C.S. Campbell, E.A. Kellogg, P.F. Stevens. 1999. Plant systematics: a phylogenetic approach. Sinauer Associates, Inc. Sunderland, Massachusetts.
Snyder, J.R., A. Herndon and W.B. Robertson, Jr. 1990. South Florida rockland. in R.L. Myers and J.J. Ewel, eds. Ecosystems of Florida. University of Central Florida Press, Orlando.
Wunderlin, R. P., and B. F. Hansen. 2003. Atlas of Florida Vascular Plants (http://www.plantatlas.usf.edu/).[S. M. Landry and K. N. Campbell (application development), Florida Center for Community Design and Research.] Institute for Systematic Botany, University of South Florida, Tampa. Accessed April 2004.

Electronic References
http://www.adaltech.com.br/evento/museugoeldi/resumoshtm/resumos/R0540-1.htm
http://www.biologicalresearch.com/Plants/plant_www.php?uniq=lanta_can


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