AbstractEcotones are a place of transition between two distinct communities. These ecotones

can be determined by finding places of high species dissimilarities, as these are the areas that are going to have the most change in vegetation. In an experiment in Econfina River State Park, ecotones were determined by sampling the populations of woody species along a path. After data was collected, it was analyzed for dissimilarity between transects given different window sizes. There was one statistically significant ecotone, which transitioned from an area of high Ilex glabra and Pinus elliottii to one of high Ligustrum sinense and palm density. Due to the nature of L. sinense, it is possible that its density is due to the high presence of light in these areas of palms. If this is the case, areas of high light should be monitored and controlled for this invasive shrub.Introduction

Sampling is an important aspect of understanding a community. It gives an ecologist information on the species diversity and abundance of each in the community. One problem that ecologists often come across is how to get accurate samples that represent the entire community. Random sampling is often used, but they may also use a species-abundance curve to decide whether they have collected all the species in a given community. This is done by taking the known species diversity of the community and creating a graph using either the rarefaction of samples or individuals. If the right side of the curve is still continuing to increase, there are still more species to be found in the community. If the right side of the curve is almost horizontal, creating an asymptote, there are few if any species left to be found. This can be used to determine whether a sample is well representative of an entire community.

An ecotone is an area where one community transitions to another. These areas are typically marked by high species dissimilarities, which means that the composition of species from one place to the next is different. They can be wide or narrow, depending on the types of changes that may be occurring and where. The area in Econfina River State Park has many different types of environments in a small area so ecotones should be narrow and well defined with transects.Methods

On a path in Econfina River State parks, transects were made every 5 meters. Inside each of these transects, the different species and densities of each of all the woody plants were recorded inside of the transects. Samples were collected from each species for identification, labeled with a number, and identified with the field guide Wunderlin and Hansen (2003) as well as the Florida Plant Atlas at a later time.

Once the data was collected, a species abundance diagram was constructed using both rarefaction based on samples and rarefaction based on individuals to determine whether all woody species in this community were collected. In the species abundance diagram, if the graph reaches an asymptote, then it is likely that all species have been collected.

The data was also used to find whether an ecotone existed in the sampled 150 m. The difference between the number of species between one transect and the next was graphed with distance. This was repeated with larger windows, so that windows of 10, 20, and 30 m. were used. The dissimilarity between one window and the next was evaluated for significance using the relocation method. Significant values were areas where ecotones were present.Results

The table below shows the identification of collected species.Table 1: Identification of Woody Species in Transects

Species Identification

1 Ligustrum sinense

2 Quercus spp.

3 Myrica cerifera

4 Ilex glabra

5 Ilex opaca

6 Unknown

7 Juniperus virginiana

8 Lyonia ferruginea

9 Pinus elliottii

10 Diospyros virginiana

11 Quercus laurifolia

12 Unknown

13 Unknown

The species abundance graph showed that the curve went almost to an asymptote. For this reason, it is likely that we found all or almost all of the species. This put the total number of woody species at around 16. These species were those listed above, as well as woody vines, palms, and oaks. When abundance of each species was plotted using a logarithmic scale, the relationship was linear.

When windows of ten meters were used, none of the dissimilarities were significant and therefore could not be considered ecotones. Dissimilarities were large enough to account for one ecotone when a twenty meter window was used, and for four ecotones when a window of thirty meters is used.

Graph 2: When each species is graphed given its rank and abundance, a line is created, with several plants having about the same amount of diversity.

DiscussionBecause of the sporadic nature of the second third of the transects, which was

measured by a separate group, it is likely that the three ecotones that were only slightly significant in the thirty meter window were due to some inaccuracies in measurement. The fourth and most significant ecotone that was found at 95-100 m. is most likely an ecotone

because it is significant in windows of 20 and 30 meters.Figure 1: The first picture was taken of the transect at 85 m, the second at 90 m, and the third at 95 m. The transect starting at 85 m had no Ligustrum sinense, while the other two transects did. The transect at 95 m did not have Ilex glabra while the two transects before it had much more of it.

The ecotone that was identified transitioned from an area that had a much higher density of Ilex glabra and Pinus elliottii to one that had a higher density of palms. The transect at 95 meters was much clearer to walk through because there was a lot less shrubs in the transect.

Graph 3: A graph of dissimilarity was made from transect compared to factor of dissimilarity. The three windows the data was tested with is provided. The red line

Table 2: Species in transects at 85, 90, and 95 meters

Transect Ligustrum sinense

Myrica cerifera

Ilex glabra Pinus elliottii

Quercus laurifolia

Palms

85-90 0 0 49 3 1 4

90-95 16 5 37 3 0 6

95-100 7 4 0 0 0 9

Ligustrum sinense is an invasive shrub that is often found in area that have been disturbed and tends to invade forest margins, where it can then invade a forest (Urbatsch 2000). It grows best in mesic soils with a plenty of sunlight, but it can tolerate low light conditions as well. In this particular case, L. sinense had higher populations in places where Ilex glabra populations were not as dense and where palm population was higher. This is possibly due to the higher light conditions that were available in areas with less I. glabra. The growth form of L. sinense was also very similar to that of I. glabra, so it is possible that these two plants are in direct competition with each other.

If L. sinense is growing better in places with a high density of palms, then it would be important to avoid disturbances at all costs to areas where invasion is a concern. It is very difficult to remove L. sinense from an environment once it is established and these areas of high light may be more susceptible to invasion.

Conclusion While some of the noise in the data was due to differences in human measurement,

there was an identifiable ecotone in transects at about 95 m. When larger windows were used, this ecotone became more pronounced in the data. The shift was one from I. glabra and P. elliottii to one of L. sinense and palms. The presence and density of L. sinense could be due in part to the increase of light availability in habitats that have a higher density of palms. This should be taken into account when creating management plans for this invasive shrub, as it may be more important to protect and remove shrubs from areas with a higher density of palms first.

AcknowledgementsI would like to thank my peers and professors for their help and guidance on this project. I would also like to thank the people at Econfina River State Park for their support.

CitationsUrbatsch, Lowell. "Chinese privet." Plant Guide. December 7, 2000. Accessed April 11, 2017.

USF Water Institute. "Plantatlas.org." PlantAtlas.org. Accessed April 11, 2017. http://www.plantatlas.usf.edu/

Wunderlin, R. P., & Hansen, B. F. (2003). Guide to the vascular plants of Florida. Gainesville: University Press of Florida.

Appendix 1: Relationship between Ligustrum sinense, Ilex glabra, and palms

Transect (m) Ligustrum sinense

Ilex glabra palms

0-5 0 1 8

5-10 0 51 4

10-15 0 30 3

15-20 0 25 6

20-25 0 32 9

25-30 7 25 9

30-35 4 22 10

35-40 11 10 12

40-45 7 4 12

45-50 3 4 9

50-55 0 58 1

55-60 12 36 6

60-65 3 16 4

65-70 9 0 7

70-75 14 6 7

75-80 12 0 3

80-85 2 34 3

85-90 0 49 4

90-95 16 37 6

95-100 7 0 9

100-105 4 0 0

105-110 4 0 0

110-115 0 0 1

115-120 8 0 0

120-125 1 4 0

125-130 2 26 0

130-135 2 7 0

135-140 5 10 0

140-145 0 5 0

145-150 0 5 0