Figure 3. Unobtrusive cheesecloth encasements were used in attaining seed count and identification of viable seeds. Encasements were constructed according to the individual plant being observed. Cheesecloth will encase the plant, attached to the wooden frame, allowed for collection and observation of seed shatter.

Phenology of two endangered Lupinus westianous

populations along Florida’s Gulf Coast

Karen Roybal DeVore

Fort Lewis College and Florida Department of Environmental Protection

INTRODUCTION

The Gulf Coast Lupine (Lupinus westianous) (Figure 1) is one of Florida’s rare and endangered native plant species (Beckner, 1982). Initially listed in April 1987, only 15 populations have been identified, each consisting of fewer than 1000 plants (Center for Plant Conservation, 2006). This lupine is found in beach dune, scrub habitats and disturbed areas (FWS, 2006). Some principal causes of decline include destruction of natural habitat due to commercial, residential and recreational development, lack of disturbance, and low levels of genetic diversity within the Gulf Coast Lupine (Center for Plant Conservation, 2006). This plant historically grew in scrub gaps created by disturbances such as fire, until lack of disturbances resulted in gap closure and excessive shading, thus decreasing populations of this species (Center for Plant Conservation, 2006). Because of the Gulf Coast Lupine’s affinity for disturbance, it is often found during the preliminary stage of post-fire plant succession (USDA Forest Service, 2006). In hurricane country, with high humidity, moisture and human interference, fire is a naturally rare occurrence in Gulf Coast Lupine habitats. Hurricanes and tropical storms, however, are a constant threat during the summer months, providing an alternative source of disturbance for Gulf Coast Lupine establishment.

Walton County, Florida is home to several known and protected populations of Gulf Coast Lupine, within Deer Lake State Park and Topsail Hill Preserve State Park, where this study was conducted (Figure 2). Due to its rarity, it is important to identify the optimal conditions for plant growth and reproduction, as well as the species’ phenology.

Phenology, the seasonal cycles of life, such as germination or reproduction, reveal a specific set of traits crucial to reproductive success (Rathcke and Lacey, 1985). Through phenological studies, annual cycles of the plant are further understood by examining responses to seasonal changes, flower emergence, blooming patterns, fruit growth, and the dropping of leaves. Understanding of flowering phenology, seed production and species interactions are crucial to plant survival. Although recovery plans are the ultimate stage of action, phenology provides the foundation of designing strategies for specific species recovery (Boersma et al., 2001). Through this knowledge, endangered species are given the chance to survive and flourish.

REFERENCES

Anonymous. Centerforplnatconservation.org. Taken from web March 2006. Lupinus westianus var. aridorum.http://www.centerforplantconservation.org//ASP/CPC_ViewProfile.asp?CPCNum=2693.

Anonymous. 2006. U.S. Department of Agriculture Forest Service. Taken from web March 2006. Fire Effects. http://www.fs.fed.us/database/feis/plants/forb/lupcau/fire_effects.html.

Anonymous. 2006. U. S. Fish and Wildlife Service 1. Taken from web March 2006. General Statistics of Endangered Species.http://ecos.fws.gov/tess_public/TessStatReport.

Beckner, J. 1982. Lupinus aridorum a new species from Central Florida. Phytologia. 50, 3: 209-211.

Boersma, D., Clark, A., Fagan, W., Hoekstra, J., and P. Kareiva. 2001. How Good Are Endangered Species Recovery Plans? BioScience. 51, 8: 643-649.

Mckee, R. 1948. The Legumes of Many Uses. U.S. Department Agriculture Yearbook. 701-726.

Julen, G. and E.Akerberg. 1948. Insects and Seed Setting in Agricultural Plants. Abstract in Herbage Abs. 18, 4: 899.

Rathcke, B., and E. Lacey. 1985. Phenological Patterns of Terrestrial Plants. Annual Review of Ecology and Systematics. 16: 179-214.

ACKNOWLEDGMENTS

I’d like to extend a special thank you to Dr. Julie Korb for her support and help in conducting this study, and to the staff at Topsail Hill State Preserve, Deer Lake State Park, and the Florida Department of Environmental Protection Division of Recreation and Parks for their time, knowledge, and encouragement.

Additionally, I would like to thank Morgan Dezendorf-my eyes and ears of the course.

STUDY OBJECTIVES

The objectives of this study are: 1) to observe the phenological growth patterns of two Florida populations of Lupinus westianous; and 2) to determine if flowering and seed production differs between the two populations.

It has been hypothesized that areas of higher disturbance will yield more flowering and higher seed production than areas of low disturbance (Center for Plant Conservation, 2006). Because Gulf Coast Lupine relies heavily on disturbance, it is expected that populations within Topsail Hill Preserve State Park will have higher flowering and seed production due to relatively recent disturbance by Hurricane Ivan and because few areas within the park are inaccessible to visitors, thus increasing the potential for disturbance.

EXPERIMENTAL DESIGN

Field reconnaissance occurred in April and May, 2006, to identify 2 population of Gulf Coast Lupine in each park that represent small to medium size lupines (0cm-30.48cm) and medium to large lupines (30.49cm+). Phenological observations were made from May- October, 2006. Within each plot, 30 lupines were randomly identified and inconspicuously marked with a 4 inch painted nail, which allowed for continuous measurements throughout the study.

STATISTICAL ANALYSIS

Number of flowers, total number of seeds, and seed/flower ratio will determine the fertility of individual plants. A two-sample t test will be used to determine reproductive and phenological variation between the two populations if the data are normally distributed. n=2, p=0.05.

KEY RESULTS

Primary growth observations

(prior to seed dispersal and dormancy)

•70% of the Deer Lake population were small-medium size (Figure 4)

•37% of the Topsail Hill population were small-medium size (Figure 5)

Mean viable seed production (Figure 6)•The mean production for the Topsail population was 93•The mean production for the Deer Lake population was 28

Mean primary growth (Figure 7)

•The Deer Lake population experienced a mean of 0.395 cm./month

•The Topsail Hill population experienced an mean of 1.026 cm./month

General observations (Table 1)

•Inflorescence for both populations began in late April

• Anthesis for both populations occurred in early May.

•Topsail State Park, flowers were generally smaller and a lighter shade of purple, which were observed until mid May.

•The flowers of the Deer Lake population were found to be larger and darker in coloration, remaining until early June.

•Bees were observed within the Topsail lupine flowers

• Upon collection of the cheesecloth encasements of Deer Lake, small chew holes were observed.

Figure 2. Map of coastal areas within Walton County, Florida. Study areas, Deer Lake State Park (east H.W. 30-A) and Topsail Hill State Preserve (west H.W. 30-A) are located approximately 17 miles of each other (Miralda, 2006).

                      

Figure 1. Gulf Coast Lupine in vegetative growth state; April 2006.

Figure3. Gulf Coast Lupine infloresence and seed set; May 2006.

  Sun Exposure Surrounding Water Source Inflorescence Pollinators Anthesis Seed Shatter Flower Color Flower Size Growth Pattern

Topsail Hill direct, shade Morris Lake (fresh) late April self, bees early May June purple small sporadic

Deer Lake direct Gulf of Mexico (salt) late April self, rodent early May June blue purple medium bunched

CONCLUSION

Due to observations of mean population primary growth, viable seed production, size distribution, and current disturbance patterns, the study hypothesis has been supported; Topsail Hill State Preserve produced more successful Gulf Coast Lupine populations.

Table 1. Phenological observations for study populations of Gulf Coast lupine within Topsail Hill State Preserve and Deer Lake State Park.

FIELD METHODS

For each lupine, observations were made on general inflorescence and anthesis, pollination mechanisms pollen release, seed production, and seed shattering as well as overall seasonal growth patterns. Due to this season’s unusually early flowering (early April), general observations were made on inflorescence, anthesis, and pollen release patterns. The mechanism of pollination was observed by noting the specific pollinator the Gulf Coast Lupine attracts. Studies have observed that most lupines producing blue, white, and yellow flowers are self-fertilizers, although some crossing within (although not between) species may occur (Mckee, 1946 and Ritchey, 1947). It has also been reported that despite the fact that some plant species considered to be self- fertilizing, seed setting is improved by insect visitation (Julen and Akerberg, 1948).

Seeds were collected, by means of a cheesecloth encasement around 10 percent of the observed lupines (Figure 3), and counted to quantify seed production Seed viability was identified according to physical characteristics of the seed. The approximate dates of seed shattering and the mechanism of seed dispersal were also noted. During each critical phase photographs were taken for documentation. In addition to phenological observations, all significant disturbances affecting the study sites were noted.

Figure 6. Mean viable seed production within two endangered Lupinus westianous populations in Santa Rosa Beach FL.

0

20

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140

Topsail Hill Deer Lake

Population Locations

Mean

nu

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Population Location

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./mon

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Figure 7. Mean primary growth observed in two endangered Lupinus westianous populations in Santa Rosa Beach FL.

Figure 4. Observed size distribution of Lupinus westianous within Deer Lake State Park, FL.

medium-large30%

small-medium70%

Figure 5. Observed size distribution of Lupinuswestianous

within Topsail Hill State Preserve, FL.

small-medium, 37%

medium-large, 63%