Strategic Plan for Exotic Removal

North Thousand Islands

Cocoa Beach, Florida

Background:

In 1986, concerned about the potential development of the Thousand Islands, the City of Cocoa

Beach approached Brevard County and the State of Florida for assistance in acquiring the North

Thousand Islands property. In 1988, the property was purchased for $3,230,950 by a consortium

of the City of Cocoa Beach, Brevard County and the State of Florida. In 1991, the property was

leased to the City of Cocoa Beach (Lease #3923) to manage “for the conservation and protection

of natural and historic resources and for resource based public outdoor recreation.”

As required by the terms of the lease, the City developed and submitted a management plan for

the North Thousand Islands in 1994. The 1994 management plan was updated by the City’s Land

Management Committee, endorsed by the City Commission and approved by the Florida

Department of Environmental Protection in 2012.

Consistent with the terms of the lease, both the 1994 and 2012 management plans include

language concerning the management or control of exotic species. The 2012 management plan

includes a provision for the development of a strategic plan “for the removal or control of

exotic, invasive or nuisance species and for the restoration of natural plant communities.”

Current Conditions:

Current extent and composition of exotic vegetation in the North Thousand Islands is as noted in

the 2012 Management Plan for the North Thousand Islands:

The uplands within the North Thousand Islands are heavily infested with non-native

plants. The most problematic species are Brazilian pepper and Australian pine. These

two species account for the vast majority of the acreage of invasive non-native

vegetation. While most of the Australian pine is limited to the larger spoil islands (~20

acres), Brazilian pepper is mixed with Australian pine on the larger spoil islands as well

as smaller spoil islands, and on the higher portions of ditch banks associated with ditches

created for mosquito control. Melaleuca is found in a few discrete upland areas

estimated to total less than 5 acres.

The management plan also includes a table listing exotic plant species found in the North

Thousand Islands. Most of the additional exotic species are found in association with Australian

pine and Brazilian pepper.

The following graphic shows the general location and extent of the primary non-native plants

(Brazilian pepper and Australian pine) in the North Thousand Islands. The area circled in red

denotes an island with dense Australian pine and Brazilian pepper that is scheduled to be used

as a spoil site in an upcoming channel maintenance project. Total acreage of exotic infestation is

estimated at 35 acres.

Scientific Name Common Name EPPC Category Govt. List Degree of Infestation

Cassia javanica Pink Shower Moderate

Casuarina equisetifolia Australian Pine 1 P High

Casuarina glauca Suckering Australian Pine 1 P High

Catharanthus roseus Madagascar Periwinkle Moderate

Cupaniospis anacardioides Carrotwood 1 N Moderate

Lantana camara Lantana 1 Moderate

Melaleuca quinquenervia Melaleuca or Punk Tree 1 N, P Moderate

Momordica charantia Balsam Apple Moderate

Schefflera actinophylla Australian Umbrella Tree or

Octopus Tree 1

Moderate

Schinus terebenthifolius Brazilian Pepper 1 N, P High

Washingtonia robusta Washington Fan Palm Low

Yucca aloifolia Spanish Bayonet or Aloe Yucca Low

Strategies:

Common methods of exotic plant control include:

1) Clear and grub/pile and burn: trees removed with root systems, then piled and burned

2) Clear and grub/chip: trees removed with root systems, then chipped

3) Cut stump/pile and burn or chip: cut tree, treat stump with herbicide, pile and burn or chip

4) Basal bark: herbicide applied to base of trunk, tree left standing

5) Foliar herbicide: herbicide applied to foliage

6) Mulching in place: grinding with specialized equipment that grinds the tree down to

soil surface (e.g. “Brontosaurus”)

Clearing and grubbing involves the use of large equipment which would be transported to the islands by barge. The clear and grub/pile and burn strategy was used in the South Thousand Islands on North and West Crawford islands. Similarly, mulching in place involves large equipment transported by barge. Due to restricted access on several of the islands (shallow water, mangrove shoreline) use of these strategies will only be an option on a limited number of islands. Because of the need to transport large equipment by barge to work sites the clearing and grub and mulching in place methods are generally more expensive than other methods but are more effective at preventing regrowth from stumps and roots. The cut stump method was used in the South Thousand Islands on South Crawford island. Australian pine, Brazilian pepper and other exotics were cut down and herbicide was applied to the stumps. The cut material was placed in piles and burned. Basal bark treatment was used throughout the Thousand Islands Conservation Area (South Thousand Islands) as an initial treatment of Brazilian pepper and other exotic plants. Following the strategic plan for exotic plant control developed for the Thousand Islands Conservation Area, most Australian pines were not treated as part of this initial effort however basal bark treatment is an effective method for controlling Australian pine. Foliar treatment has been primarily used for control of sprouting or plants at the small shrub scale or regrowth rather than treating mature plants. Treating large trees with a foliar spray may result in drift of herbicide which could affect non-target plants. Clear and grub or cut stump with burning or chipping is the preferred method for treating areas predominantly vegetated by Australian pine. Cut stump or basal bark treatment is commonly used to treat areas dominated by Brazilian pepper. Follow-up Treatment and Planting: Once the exotic plants are treated, it is anticipated that regular herbicide retreatment will be required in most areas as there is an abundant seed bank for Australian pine, Brazilian pepper and other exotics present in the soil. Although it is anticipated that native species will thrive once the exotics are removed, exotics will be present in the long term. As the coverage of native species increases, this will inhibit the propagation of exotics. Some of the areas where exotic, invasive or undesirable plants are treated or removed will be revegetated with appropriate native species such as mangrove, sabal palm, palmetto, seagrape, oak, cedar, wax myrtle, Florida privet and similar species. In other areas, natural recruitment will be the primary method of habitat restoration following the removal of exotic species. In the Thousand Islands Conservation Area (South Thousand Islands) planted sites were located adjacent to residential areas and were planted creating buffers for aesthetic purposes as well as habitat restoration/creation. Decisions on where planting is necessary or appropriate will be made based on an assessment of individual sites. Buffers shall be a minimum of 30’ in width and include at least 15 plants per 100’ of buffer length planted on a minimum of 8’ centers. Plants shall be native shrubs, trees or palms such as those noted above which will thrive and provide habitat in the area to be planted. Estimated cost per 100’ segment (or portion of 100’) based on $20 per plant is $300. Planting designs developed for specific sites may have wider buffers or include a larger planting area and may have denser plantings.

Removal and Restoration Schedule: With one exception, a A phased removal of Australian pine, Brazilian pepper and other exotics is proposed. This exception is the oak hammock area found on the northern end of large island slated to be addressed in Phase 4 of the exotic removal process. This 3-5 acre area features mature oaks that are being overgrown by Brazilian pepper. It is recommended that exotics in this area be treated and removed as soon as possible to protect and preserve this resource. As an initial step, groupings of areas with exotic vegetation have been developed. Exotic plants within individual groups will be treated at the same time as a group while treatment of the various groups will be phased over time. Treatment of various areas within a group may occur at the same time or over time as funding and other resources become available. While t The precise timing of the various phases will depend on the availability of funding for these projects as well. , similar to the strategic plan for It is anticipated that there will be a minimum of three to five years between phases. As an example, the Thousand Islands Conservation Area Strategic Plan for Exotic Removal schedule envisioned a three phase removal of exotics with a three year period between each phase. Due to lack of funding, only the first phase and a portion of the second phase have been completed after six years. It is likely that obtaining funding and the limited availability of city staff for this type of project will present similar challenges in the North Thousand Islands. support implementation of each phase will be separated by a minimum of a three year period. This will allow for revegetation (either by planting or natural recruitment) of cleared areas and restoration of the aesthetics of the area. The following graphic shows the groups and phases for treatment as well as the oak hammock area located in Phase 4:

Oak Hammock includes a 3-5 acre area near the north end of the large island included in Phase

4. This area is recommended as a first priority for immediate treatment. While cut sump with

stacking and pile/burn of exotics in this area would be the preferred treatment basal bark

treatment and later removal of exotics may be considered. The following graphic shows the

approximate area of the oak hammock proposed for treatment.

Phase 1 includes three islands south of the 200 channel and adjacent to residential areas. As

previously noted, the island circled in red contains a spoil site scheduled to be used in an

upcoming channel maintenance project. It is our understanding that the permit issued for this

project requires the removal of exotic species from this island. Perhaps the two adjacent islands

included in this phase could be included as part of the spoil site project. Either clear and grub or

cut stump with chipping or burning is the recommended treatment method for these islands as

they are predominantly covered by Australian pine. Basal treatment of Brazilian pepper and

some of the smaller exotic plants may be used. Revegetation using appropriate native species is

recommended for the islands treated in this phase.

At the spoil site, revegetation is proposed along the southeastern shoreline. The northeastern

shoreline is presently vegetated by a dense mangrove fringe. The length of the restoration are is

approximately 420 feet. Estimated plant cost is $1500..

Island 200a is located south of the spoil site. Much of the shoreline presently has a fairly dense

mangrove fringe, with the exception of the northeast corner which is slated for planting. The

length of the revegetation area is aproximately 160 feet. Estimated plant cost is $600.

The 200bc islands are two small islands located north of the spoil site. While both have

mangrove fringe, the fringe is narrow. To provide desired buffering revegetation is proposed on

both islands. The length of the buffers are: 200b - 140 feet; 200c - 150 feet for a total of 290

feet. Estimated plant cost for 200b &c is $900.

Phase 2 includes areas along and adjacent to Minuteman Causeway south to the 500 channel.

Recently the City of Cocoa Beach and Keep Brevard Beautiful undertook a project to treat

Brazilian pepper along Minuteman Causeway however some Brazilian pepper and other exotic

vegetation remain in this area. Noting that the areas dominated by Australian pine are small

(generally an acre or less) and access is difficult the recommended treatment is cut stump and

burn. The Most areas dominated by Brazilian pepper are accessible from Minuteman Causeway

or Roosevelt School. Cut stump and chip is recommended in these areas. Some areas of Brazilian

pepper that are difficult to access may be treated using basal bark treatment. Natural

recruitment rather than revegetation is recommended in Phase 2 with the exception of one

group of Australian pines opposite LaRiviere Drive. As shown below, a revegetation area

approximately 360 feet long is proposed in this area. Estimated plant cost is $1200.

Phase 3 includes a series of islands along the 300 channel. Basal bark treatment is

recommended for the areas dominated by Brazilian pepper, Natural recruitment rather than

revegetation is recommended in these areas. The t Two areas islands dominated by Australian

pine are found in this phase; a western island approximately an acre in size and an eastern

island approximately 5 acres in size. relatively small but access is limited. Cut stump and burning

is recommended along with basal bark treatment of smaller exotics. Natural recruitment is

recommended at the western location; revegetation is recommended at the eastern site.

Much of the shoreline of the eastern island on the 300 channel features a dense mangrove

shoreline. Along the southern shoreline, across from the developed area, the mangrove fringe is

less dense. A revegetation area approximately 200 feet long is proposed for this area. Estimated

cost for plants is $600.

Phase 4 includes a 15 acre island located along the 100 channel adjacent to a residential area.

The area is predominantly vegetated by Australian pine with the exception of the previously

noted oak hammock and access is available at a number of locations. Clear and grub or cut

stump followed by chip or burn is recommended for this site along with basal bark treatment of

smaller exotics where appropriate. Revegetation is recommended for this site. Two revegetation

areas are proposed: a small revegetation area north of the oak hammock and a larger

revegetaion area south of the hammock. In the graphic below, the oak hammock is circled in red

and the north and south restoration areas are shown in green. The following graphics show the

north and south revegetation areas. Length of the northern area is approximately 250 feet; the

southern area is approximately 1350 feet with a total; length of 1600 feet. Approximate cost of

plants is $4800.