Attach__No__1B_-_InvaSpeciesMgmtPlanMacDillAFB.docx

Invasive Species Management Plan MacDill AFB October 2013

APPENDIX U

Invasive Species Management Plan MacDill Air Force Base Tampa, Florida

Prepared by 6 CES/CEVN October 30, 2013

Table of Contents

Appendix UA - Invasive Species Management Elements Appendix UB – Summary of Invasive Species Control Work at MacDill AFB

1.0 INTRODUCTION AND BACKGROUND

The U.S. Air Force (USAF) takes seriously its responsibility of stewardship for the land with which it has been entrusted. One aspect of responsible maintenance of the land is the control of invasive and nuisance plant species, particularly non-native plants.

1.1 Location

MacDill AFB is located in west central Florida at the southern tip of the Interbay Peninsula in Hillsborough County. The base covers an approximate area of 5,638 acres, and is surrounded by Tampa Bay to the south (Middle Tampa Bay), west (Old Tampa Bay) and east (Hillsborough Bay), and the City of Tampa to the north and west. All or parts of the counties of Pinellas, Pasco, Hernando, Polk, Hardee, DeSoto, Manatee, and Sarasota are within a 50 mile radius (USAF, 1994a). Figure 1 illustrates the location of MacDill AFB with respect to the region.Figure 1 - General Location of MacDill AFB

Much of the base is considered urban, which includes industrial, commercial, administrative, residential, and semi-improved lands. Nearly all of the property has been disturbed in some manner or another during the 70+ year history of MacDill AFB. There are about 1,168 acres of “wooded acreage” on the base, all of which are highly prone to invasion by non-native and nuisance plant species.

1.2 What Are Invasive Species

Plants or animal that have been moved from their native habitat to a new location are called ‘non-native’, ‘exotic’, ‘non-indigenous’ or ‘alien’. Sometimes these plants or animals struggle to survive in the new location because the organism has very specific climactic or ecologic conditions needed for survival. More frequently, the transplanted organism is tolerant of change and is able to adapt to slight to moderate changes in environmental conditions to ensure its survival. These organisms frequently co-exist compatibly with the native species and do not substantially alter the habitat. Occasionally, however, the introduced species not only thrives in its new environment but dominates it. The exotic species reproduces rapidly, quickly spreading throughout the new environment where it out competes native species for available resources. This leads native species to struggle for survival and, if left unchecked, may eventually result in a monoculture where species diversity is eliminated and only the dominant species remains. Aggressive species which wreak havoc on native ecosystems, causing ecologic damage are classified as invasive species.

1.3 Executive Order 13112

The Federal government has identified the spread invasive species as an issue that should be addressed and has created an Executive Order which mandates the control of invasive species. Executive Order 13112 defines an invasive species as one that is 1) non-native to the ecosystem under consideration and 2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health. Interestingly, the Executive Order extends beyond the potential for a species to cause negative ecologic impacts to include adverse effects to the economy and public safety. The Executive Order states that a Federal agency may make a determination that the benefit of an action, which may lead to the introduction or spread of an invasive species, clearly outweigh the potential harm caused by the species and take steps to minimize the harm.

1.4 How are Invasive Species Introduced

Invasive species are introduced in a variety of ways. The means and routes by which they are introduced are called invasion “pathways.” Some non-native species are intentionally introduced for beneficial purposes but later turn out to be invasive. In Florida, examples include Brazilian pepper, which was introduced as an ornamental plant because it produced beautiful red berries in the winter. Many invasive species are unintentionally introduced; they move as unknown stowaways and “hitchhikers” when people and their products are transported by air, water, rail, or road. A common invasive species in the southeast that was unintentionally introduced is Cogongrass, which first arrive in neighboring Alabama in 1912 as packing in a Satsuma orange crate. Cogongrass quickly infests disturbed sites, creating a monoculture which offers neither forage value to livestock nor ecologic benefit to native wildlife. Another example of an unintentional introduction of an invasive species in the southeast is fire ants which entered the U.S. in soil that was removed from ships that transported goods to the U.S. Where they have established in the southern U.S., they can be found in large numbers. They can seriously injure livestock, pets, and humans. They also feed on crops and build large, hard mounds that damage farm and field machinery.

Although non-native fauna have been introduced on MacDill AFB, none have yet been found to be significantly degrading the natural community structure or causing serious ecological impacts. On the other hand, numerous non-native plant species have become established on the base, and several have demonstrated highly invasive tendencies, quickly spreading and impacting native ecology. Often, the spread of an invasive plant species can be directly linked to disturbance. When native habitat is altered through construction, mining, or other land disturbance, and invasive species are present nearby, they quickly establish on the disturbed site, and take over before the native species have a chance to recover.

1.5 Where are Invasive Species Found on MacDill

Following establishment of the base in the early 1940’s, the Air Force immediately began altering the land to suit its use as a military installation. Miles of ditches were dug to divert rainwater and drain low lying areas. Dredge spoil was spread over large areas to elevate the land. Mosquito ditches were dug throughout the mangrove estuaries. Large areas of native habitat, historically dominated by longleaf pine, palmetto, and open prairie were bulldozed over for short term use as landfills, borrow pits, parking, staging areas, temporary storage, training grounds, or other functions essential to the military mission. All of this activity disrupted native vegetation, overturned the land, and created disturbed habitat ready to be covered by opportunistic invasive species. By the time invasive species management was fully incorporated into the conservation lexicon, nearly all of the 5,638 acres of MacDill AFB had been disturbed or altered in some form or fashion. When Executive Order 13112 was signed in 1999, nearly all the undeveloped areas of MacDill AFB were impacted by exotic invasive species, and some of these areas were completely overrun. Areas of disturbance in undeveloped area noted from review of historical aerial photographs covering the period from 1945 to 1984.

The administration and airfield areas of MacDill are mowed and maintained, limiting the establishment of invasive species.

Fortunately, the base is relatively small, and approximately two thirds of the base is developed or otherwise maintained, which dramatically limits the potential for the establishment of invasive species in these areas. Only about 2,000 acres of the base are considered largely undeveloped, predominantly wooded or left to grow wild. It is these wooded areas where invasive species have staked their claim and in many cases dominate the landscape.

To date no formal surveys to define or quantify invasive species on the base have been accomplished. It was felt that the limited available funds would be better spent on treatment and control of nuisance and invasive plants, rather than detailed surveys. An informal assessment of the undeveloped areas of the base was accomplished in 2000 to identify areas of dense Brazilian pepper coverage. At that time, Brazilian pepper was by far the predominant invasive species on base, and the primary focus of the invasive species control program. The assessment mapped roughly 350 acres of dense Brazilian pepper, primarily along roadways, and helped focus the invasive species eradication program during its early stages of development. The informal survey, however, woefully underestimated the total coverage of Brazilian pepper as previously undiscovered areas were identified in later years.

2.0 INVASIVE SPECIES MANAGEMENT

Invasive species fall into two major categories, flora and fauna, and examples of both of can be found on MacDill AFB. Non-native or nuisance fauna, such as coyote (Canis latrans), feral hogs (Sus scrofa), and nutria (Myocaster coypus) have been identified on MacDill AFB; however over the past 12 years sightings of these species are rare suggesting that their populations are not expanding rapidly. There are currently no management or control efforts being accomplished to control the spread of non-native fauna on MacDill AFB because the local populations do not currently represent a threat to native ecosystems. One non-native animal species, the nine banded armadillo (Dasypus novemcinctus), has become somewhat of a nuisance on the base, particularly on the golf course where they dig holes foraging for grubs and damage playable areas of the course. The golf course applies insecticide to the turf in an effort to control grub populations and reduce foraging by armadillos. Areas of invasive species control as of 2013

Invasive plant species are likely the most detrimental problem affecting natural resources at MacDill AFB, adversely affecting habitat for native fish and wildlife in both wetlands and uplands, including habitat for threatened and endangered species. The high ecological and economic cost of these undesirable invasive species has been identified within the Tampa Bay region, statewide, and nationally.

A non-native invasive is a plant that is imported from somewhere outside the state that spreads quickly, outcompeting native vegetation and altering native community structure. Not all non-native plants are invasive. They become categorized as invasive based on aggressive tendencies and their ability to replace native plants in natural plant communities. Likewise, not all native plants are completely beneficial. Some native species have invasive tendencies and can quickly become a nuisance if favorable conditions exist for rapid spread. Disturbance of the ecosystem is the activity that most often leads to the spread of both non-native and native nuisance species. Examples of native species which have invasive tendencies here at MacDill AFB include cattails (Typha latifolia) and grape vine (Vita rotundifolia). Mechanical cattail removal completed in Lewis Lake in 2004 was only a temporary solution.

The Florida Exotic Pest Plant Council (EPPC) classifies non-native plants by their potential for impacts to Florida ecosystems. Category I pest plants are: “Invasive exotics that are altering the native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives.” Category II exotic species are: “Plants on their way to becoming Category I because of ‘increased abundance or frequency’ in Florida plant communities.”

Efforts to control the spread of non-native invasive species on MacDill AFB began in 1994 when the mechanical clearing of Brazilian pepper from about 64 acres was accomplished using a hydro-ax machine. From 1995 through 1999 about 506 acres were mechanically cleared as part of a state-funded wetlands restoration effort completed in partnership with the Southwest Florida Water Management District (SWFWMD). The SWFWMD project eradicated Brazilian pepper and other non-native species in the southeastern portion of the base, primarily around the south golf course.

Even with completion of the earlier mechanical clearing work, by the year 2000 Brazilian pepper was still by far the dominant invasive plant species on the base. It was present along every roadway throughout the western and southern portions of the base. It formed thick walls along the forest edges of the wetlands and planted pine areas, and frequently extended back into the understory as well. 6 CEV accomplished informal mapping and quantification (acreage) of roughly 26 sites which were heavily infested with Brazilian pepper and initially focused resources on treating Brazilian pepper on these sites. Between 2000 and 2004 annual Operations and Maintenance money was used to let a series of annual contracts which aimed to eradicate Brazilian pepper from identified areas of heavy infestation. Initially invasive species eradication work was accomplished through mechanical clearing; however, it was quickly realized that control of MacDill’s invasive plant species was not possible using mechanical clearing alone given the annual O&M budget of roughly $65,000. Brazilian pepper was spreading to cover more acreage each year than could be cleared. Brazilian pepper infestation along the forest edge was common along nearly all of the roadways in the southern and western portions of the base back in 2000.

During the four year period between 2000 and 2003 Brazilian pepper was treated on individual sites ranging in size from five to 35 acres in an effort to eradicate concentration of dense Brazilian pepper. During 2004, the last year of individual site treatment, four large sites totaling 520 acres were treated along the southern edge of the base. Over the five year period from 2000 through 2004 roughly 899 acres were treated at a cost of $316K. As of 2005, with the exception of a couple of large blocks of planted pine, it was felt that nearly all of the wooded areas of the base had been treated at least once for Brazilian pepper. Beginning in 2005, the Brazilian Pepper Eradication Program was retooled and renamed to better manage invasive species on MacDill AFB. The program was renamed the Invasive Species Control Program and the scope of treatment was expanded to include numerous other invasive and nuisance species that were spreading across the base, sometimes as a result of eradication of Brazilian pepper. The program also began managing the land on a quadrant basis instead of smaller individual sites. The undeveloped portions of the base have been divided into four quadrants and invasive species control is accomplished across the entire acreage of the quadrant. The quadrants range in size from 400 acres (Quadrant 4) to 711 acres (Quadrant 1). Limited mechanical clearing of invasive species was occasionally accomplished during this period, as funding allowed. Near the end of fiscal year 2011, 6 CEV established an Indefinite Deliverable Indefinite Quantity (IDIQ) contract through the 6th Contracting Squadron (6 CONS). The IDIQ contract allows MacDill to best compete for End of Year funding which is often available but must be awarded immediately. The central focus of the IDIQ contract is invasive species management but it also includes tasks, such as prescribed burning and native vegetation planting, to assist with the restoration of degraded habitat areas. With award of the IDIQ contract, the program was again renamed the Habitat Restoration Program. The central focus of the program remained the control on invasive and nuisance species on a quadrant basis. Quadrants established in 2005 during retooling of the invasive species control program.

Between 2005 and 2013 each of the four quadrants have been treated a minimum of three times each. Table 1 summarizes when each quadrant was treated. Between 2005 and 2014 nearly $861K has been spent to control invasive species on MacDill AFB.

Table 1 – Invasive Species Treatment by Quadrant 2005 through 2014

X

X

X

B3

X

X

X

X

X

X

Notes:

1 denotes the year that treatment was actually accomplished, not when funding was received 2 2014 work has been awarded but not yet started 3 denotes only half of the quadrant was treated that year.

A summary of the invasive species control work that has been completed at MacDill AFB since 2000 is provided in Appendix B. The table provides a brief description of the type of treatment implemented, the sites that were treated, and amount of funding spent each year.

3.0 INVASIVE PLANT DESCRIPTIONS AND PRESCRIPTIONS

The most significant invasive species at MacDill AFB, which are currently included in the Habitat Restoration IDIQ contract, are discussed below. Plant descriptions are provided from the Florida Exotic Pest Plant Council guide titles ‘Identification and Control of Non-Native Invasive Plants in the Tampa Bay Area’.

3.1 Brazilian pepper

Brazilian pepper (Shinus terebinthifolius) is the biggest threat to native species associated with wetlands at MacDill AFB. This species is one of five currently being managed on the base. Brazilian pepper is a large, multi-trunked shrub or tree with arching and crossing branches. It can grow to 40 feet tall, forming dense monoculture thickets. Leaves are evergreen, glossy green and alternate. Often toothed, leaves are compound with 3 to 11 (usually 7 to 9) leaflets. Leaflets vary in shape, but are generally elliptical to oblong and 1 to 2 inches long. Crushed leaves smell peppery and like turpentine. Female plants form small white flowers almost every month of the year, but most profusely in the fall season. Females also produce large clusters of red berries in the fall and winter. Brazilian pepper is a relative of poison ivy and poison sumac. Sap from the trees may irritate skin and pollen may cause respiratory irritation. Upper photo is a close up of Brazilian pepper leaves and berries, bottom photo shows a medium sized tree.

Brazilian pepper prefers wet sites such a lake shores, swamps and wetlands, but can survive in standing water. It tends to occupy the same habitat as mangroves. The roots of the Brazilian pepper are said to have an allelopathic effect on competing plants (National Park Service 2002). It is an aggressive species that will quickly colonize disturbed areas. It prefers sunny conditions but can survive in moderate shade, growing slowly and waiting until a disturbance allows it to spread quickly.

There are many available procedures for control of Brazilian pepper, including chemical, mechanical, and biological techniques. The main method of control at MacDill AFB to date has been foliar treatment using a USEPA/FDACS approved herbicide, usually a triclopyr formulation such as Garlon®. The treatment is generally effective, but must be followed up repeatedly to prevent re-sprouting and control of new recruits arising from seed or from trees that were not completely killed. The longer term goal is to achieve control of the Brazilian pepper and allow natural recruitment of native plant species, augmented by planting of natives, to establish a native understory that prevents Brazilian pepper recurrence.

Generally, Brazilian pepper control work at MacDill AFB has rotated annually among four main areas (quadrants) on the base, with each quadrant being treated roughly every two to three years. This quadrant based chemical treatment approach has resulted in a substantial reduction in the occurrence of Brazilian pepper throughout the base and has effective reduced and controlled the largest infestations; however it has not necessarily facilitated the establishment of native plants or substantially improved habitat values. With the foliar application, the standing dead plants remain for some time. The standing dead plants limit the growth of desired natives, encourage the growth of nuisance vines, restrict access for people and vehicles, and generally present an unattractive appearance. The dead trees also restrict wildlife movement and provide little to no habitat value. The current rotation schedule provides the pepper, given its rapid reproductive and growth rate, ample time to reestablish. Area of planted pines on MacDill after the understory vegetation, primarily the invasive Brazilian pepper, was clean-out using a hydro-ax.

Biological control is Florida’s preferred management strategy for Brazilian pepper. MacDill AFB may deploy state-identified forms of biological control in conjunction with other efforts. One element of this strategy is to establish native plants that inhibit growth of Brazilian pepper, such as Wax myrtle (Myrica cerifera) and Love vine (Cassytha filiformis). Nearly all Brazilian pepper recruitment is through fruits eaten and dispersed by birds or mammals as seeds, and ingestion is a requirement for seed germination. Therefore, another element of this strategy may entail the placement of bird feeders stocked with native plant seeds in order to prevent ingestions and subsequent germination of pepper seeds, thereby disrupting the Brazilian pepper lifecycle (and potentially germinating native seedlings).

3.2 Lead Tree

A native to Mexico and Central America, lead tree (Leucaena leucocephala) is an aggressive invasive tree that is quickly filling in disturbed areas around the base. Lead tree is a rapidly growing shrub or small tree which can reach a height of 25 feet tall, although there is a subspecies (Leucaena glabrata) that can reach 60 feet tall (the taller species does not appear to be present on MacDill). The leaves are bipinnately compound, generally 5 to 8 inches long and consisting of numerous (usually around 15 pairs) elliptical, light green leaflets. The pale gray-brown bark is smooth and often contains numerous lenticels. The tree produces long flat reddish-brown pods as fruit, which are blunt or rounded at the end. Fruit (pods) are 5-7 inches long and an inch wide, containing 10-20 flattened seeds. The tree flowers infrequently, in tiny white to pale yellow flowers configured in a ball-like head at ¾ inch in diameter.

On MacDill AFB, this tree establishes in coastal strand and hammock communities and in creek bank habitats. It is found throughout the base property, but is particularly prevalent in the southeastern portion of the base (Quadrant 1). Similar to Brazilian pepper, it rapidly invades disturbed forest openings and sunlit edge areas, forming dense thickets that occupy the lower canopy. It will quickly invade areas that are recently cleared. These muscular stands have little wildlife value and displace native vegetation. Lead tree was originally introduced to Florida as a cattle fodder and pioneer plant for land reclamation and erosion control, and the wood also made a good fuel for early settlers. The durable tree will remain standing for decades even after it has been killed. Photo of lead tree showing leaf structure, seed pods, and the flower.

The State of Florida classifies lead tree as a Category II invasive species. On MacDill AFB the tree is quite invasive, and is every bit as aggressive as Brazilian pepper but its distribution is not yet as wide spread around MacDill as Brazilian pepper. Outside the base, the tree can be found in southern Florida from the Florida Keys to north of Tampa. The tree is killed to the ground by a hard frost, regrowing from the roots in spring, which limits its distribution in northern Florida.

Control of lead tree on MacDill is accomplished primarily through the foliar application of herbicide. The frill and girdle approach is sometimes used for larger trees, and in some instances the trees are cut down and the stumps treated with herbicide. The trees are left to die in place.

3.3 Melaleuca

Another invasive non-native species that threatens wetlands at MacDill is the tree, Melaleuca quinquinervia, better known as the paper-bark or punk tree. This fast growing tree can reach 100 feet in height. The white, multi-layered peeling bark is the trees most distinguishing feature. The narrow, lance-shaped greenish gray leaves are 2 to 8 inches long and 1.5 inches wide. The leaves smell of camphor when crushed. The tree can flower year round, producing white fluffy spikes which look something like a ‘bottle brush’. The fruits are small brown woody cone-like clusters attached to a stem. Each stem can hold up to 300 seeds.

Melaleuca has been known to cause headaches, rasher, asthma attacks and respiratory irrigation is some people. The showy “paper bark” of a Melaleuca, which earned the tree its name.

Melaleuca was first introduced to Florida as an ornamental plant in the late 1800s. The seeds of this water-loving tree were scattered aerially over the Everglades in the 1930s to create forest that would dry up the Everglades. The tree prefers wet sites such as lake shores and wetlands, but can flourish in standing water and will survive in well drained uplands as well. Mature trees can withstand frost and fire. Melaleuca grows extremely fast, and produces dense stands that displace native plants, diminish animal habitat, and provide little food for wildlife. It has become abundant in pine flatwoods, sawgrass marshes, and cypress swamps throughout south Florida. The species is well established on MacDill AFB, with a sporadic occurrence in wooded areas where freshwater, occasionally flooded areas are found.

At one time, Melaleuca was listed as an approved landscape species for MacDill AFB and was planted as an ornamental species in a few administrative areas around the base. It has long since been removed from the approved landscape list and today only a few trees remain in the administrative areas of the base. Removal of Melaleuca from the administrative areas of the base has been a low priority since the trees are essentially contained and can’t spread easily, but these remaining trees will be removed as funding becomes available.

Eradication of Melaleuca from the undeveloped wooded areas around the base has been a higher priority. Control of this species has primarily been pursued through a combination of mechanical and chemical treatment. Because of the trees tall height and dense bark, foliar application is difficult to accomplish and not very effective. Foliar application is typically only used for sapling trees (less than four feet tall). For smaller trees a hack and squirt treatment approach can be used successfully. With the hack and squirt method a machete or ax is used to make a large cut or sometimes a notch through the tree bark to expose the trees living tissue (cambium layer) and a concentrated herbicide is then applied to the cut area. Similar to hack and squirt, the frill and girdle approach is often used for larger trees. With the frill and girdle approach, a machete or ax is used to cut though the bark in a ring around the base of the tree. The ring should be cut as close to the ground as possible. A spray bottle is used to spray a concentrated herbicide solution into the freshly cut ring. In both cases, the tree is left standing to die in place. As shown above, Melaleuca frequently forms a monoculture due to its rapid growth and aggressive spread.

For especially large trees or dense stands of trees, cutting the tree down with a chain saw then treating the cut stump with a concentrated herbicide has proven the most effective. Saw cuts should be made as low as possible on the tree and should be parallel to the ground so that the herbicide will not run off when applied to the cut stump. Herbicide should be applied as soon as possible after cutting the tree down. The concentrated herbicide should be applied to the cut stump using a spray bottle or dropper bottle to insure efficient use of the herbicide. Dropper bottles are very effective for concentrating the herbicide solution to the cambium area, thereby reducing the amount of herbicide needed to kill the stump. Felled trees are typically left where they fall on the ground to decompose. Leaving the tree to decompose on the ground can occasionally result in regrowth from the cut portions of the trees if conditions are right and there is good contact with the soil. Ideally the trees should be cut into sections and stacked so that most of the wood is off the ground and has no contact with the soil. This should dramatically reduce the potential for regrowth but is labor intensive and therefore more expensive.

Herbicides used to treat Melaleuca, either through foliar application or concentrate to the cambium layer, include Glyphosate, imazapyr, and triclopyr. Use of a granular herbicide spread over the ground may also be very effective at controlling Melaleuca, particularly where it is found in large, dense monoculture stands. Since Melaleuca is typically found in low lying area where standing water may be present, a granular herbicide that is registered for application over water.

3.4 Cogon Grass

Cogon grass (Imperata cylindrica) is a tall perennial grass found throughout Florida and several other southeastern states. Cogon grass reportedly arrived in the United States in 1912 near Grand Bay Alabama as packing in a Satsuma orange crate. It was introduced in Florida in the 1930’s and 1940’s as possible forage for cattle and for soil stabilization. It was later determined to have no forage value and of little economic benefit and was categorized as a serious pest. It is considered one of the “Top 10 Worst Weeds in the World”.

The grass is fairly tall, ranging in height from 2 to 5 feet, with light green to yellow blades. It will go dormant in the winter, turning a dull brown and appearing dead. The leaves of the grass are serrated along the edge, giving it a rough feel. The leaves are strongly pointed and often have a weathered or brownish appearance. A distinguishing feature is a well-defined midvein which is often whitish in color and slightly offset to one side. Another distinguishing feature is the fuzzy, white, plume-like seed head, which is most commonly present from March to June but can be occasionally seen throughout the year in Florida. The base of the grass, at the ground surface, is cylindrical instead of flat, and the minimal stems are very hairy. The grass leaves appear to rise right out of the ground. The grass has a large root mass, in fact, the majority of the plants mass is below the ground surface. The rhizomatous roots are white, with pointy tips on the new shoots. Most of the root mass is found within the top six inches but they can penetrate to a depth of four feet. It has been reported that the rhizomes exude an allelopathic substance, killing adjacent plants. The grass primarily spreads through rhizome creep, although the plant can spread through seed as well. This photo from the Georgia Department of Agriculture shows leaf structure of cogon grass with its distinctive mid-vein ridge.

Cogon grass prefers full sun but can survive in partial shade conditions. It is most commonly found in open fields and pastures, and is frequently reported along roadways and utility corridors. The grass can survive in fine sand to heavy clay. It cannot survive in deep shade nor can it survive in cultivated areas, as the routine tilling disrupts root growth and spread. Cogon grass is found throughout MacDill AFB, generally in small patches (less than 400 square feet) in open fields and near the tree lines along roadways. Although no formal surveys have been accomplished to date, Quadrant 2 appears to have the largest density of cogon grass based on windshield inspections of all four quadrants.

Several methods of control of cogon grass have proven successful. One of the most effective and environmentally friendly methods is discing or tilling a patch of cogon grass. Turning over the root mass and exposing it to the sun will desiccate the roots.

3.5 Australian pine

Australian pine is an invasive tree which thrives in coastal areas and grows quite tall, however, on MacDill AFB it has not spread nearly as rapidly as species such as Brazilian pepper or lead tree. Consequently, the tree is not a large problem at MacDill AFB and it is only found in a few locations along the shoreline. It is anticipated that it will be removed from the Top Five problem species, and considered under control, by 2014.

3.6 Other Invasive and Nuisance Species

Other invasive and nuisance species that are common on MacDill include Eichhornia crassipes (common name: water hyacinth), Ricinus communis (common name: castor bean), Hydrilla verticillata (common name: hydrilla) and Vitis rotundifolia (common name: muscadine grape). The muscadine grape has likely become uncontrolled in areas due to the lack of a fire regime.

Water hyacinth was originally a major problem in Lewis Lake. In fact, in 2001 the entire 18 acre lake was completely covered with water hyacinth. Over the period of a year, the water hyacinth was treated in zones with a foliar application of herbicide. At the end of the year the water hyacinth population was significantly knocked back and the lake was placed on a maintenance program to treat any regowth or recurrence of water hyacinth. Small patches of water hyacinth are still occasionally observed in Lewis Lake, but annual maintenance has kept significant regrowth of the plant in check.

Although cattails are native to Florida and MacDill, they have created problems for wetlands. Eutrophication of lakes has allowed this shallow water species to dominate vegetation in some places, which creates problems for the wetland ecosystem as a whole and greatly affects recreational access to such areas. This was the case in Lewis Lake, which MacDill AFB is required to keep free of such weeds as part of its stormwater permit. Cattails were previously sprayed and hand-pulled, and native aquatic vegetation was planted. In 2004, the cattail had again taken over much of Lewis Lake and a project to mechanical remove the cattails was implemented. The mechanical removal of cattails was initially quite successful and provided a neat appearance around the lake very quickly. As is typical for a mechanical removal process, substantial root material, along with the existing seed bed, was left behind. Unfortunately, no follow-up treatment on the regrowth was accomplished and cattails quickly re-established throughout the littoral areas of Lewis Lake. As of 2013, Lewis Lake is receiving semi-annual herbicide treatment to keep cattail growth in check.

Grape vine is another native species that can become a nuisance. It is scattered throughout much of the planted pine areas, and also in some of the oak hammocks. The vine grows up into the canopy of the trees competing for light and other resources eventually stressing the trees. When an area of Brazilian pepper is cleared, grape vine is often the first species to establish in the site, if it is found in the surrounding areas. Mechanical treatment of grape vine, through the use of a gyrotrack, roller chopping machine, and hand clearing has been accomplished and proven to be highly effective at killing the vine up in the tree, but follow-up herbicide treatment of the vine at ground level is required to stop regrowth.

4.0 MANAGEMENT CONSIDERATIONS

4.1 Herbicide Applications

All herbicide application work at MacDill AFB is completed by personnel who possess a commercial applicator license issued by the Pesticide Certification Office of the Florida Department of Agriculture and Consumer Services. Herbicides are reviewed and approved by the USAF Pesticide Management Board prior to use. Once approved, each herbicide is entered into the Integrated Pesticide Management and Information System database and its monthly usage is tracked in the database. A monthly summary report is prepared to document the pounds of active ingredient used for each herbicide. The monthly reports are submitted to the Headquarters AM/A7 Command Entomologist.

All of MacDill’s invasive species control contracts, including the current IDIQ contract, always require a follow-up herbicide application to be applied 4-6 months after the initial treatment. Follow-up treatments are essential to ensure that the treated invasive species is killed completely. Invasive species are persistent and a mature plant is seldom killed with a single herbicide treatment. Quite frequently, the plant defoliates and appears dead, but soon sprouts new growth from the main trunk(s).

The type of herbicide application utilized depends largely on the species being controlled. For example, foliar application is most effective for Brazilian pepper and cogon grass, but much less effective on mature Melaleuca. A hack and squirt or stump cut treatment for Melaleuca has a far greater chance of success. Similarly, Lead tree and Australian pine are most effectively killed through hack and squirt or stump cut herbicide treatments.

4.2 Lessons Learned

Aerial herbicide application was accomplished in 2005 to treat areas of Brazilian pepper that were not easily accessible by wheeled vehicle or on foot. Aerial herbicide application is effective when using a selective herbicide or for treating large areas of monoculture but becomes less practical for small sites or sites with a mixture of invasive and native vegetation. This broad treatment approach invariably results in collateral damage. Although employed with some success back in 2005, the density and concentration of invasive species found on MacDill today does not warrant its use.

Retreatment and maintenance is essential for the success of any invasive species control program. A one-time treatment for an area or plant is seldom effective at controlling spread of the invasive plant. Recurring treatment is necessary to kill regrowth that occurs due to stored energy in the root system and/or an existing seed bed in the soil. Maintenance periods will last for several years, or decades, depending on the species.

For mechanical removal of trees, particularly Brazilian pepper, the direct extraction method has proven to be the most effective. Extraction removes the entire tree including most of the root system. The tree is dried out and burned for disposal. Once removed, only the seed bed remains, making regrowth far easier to control.

Mechanical clearing of invasive trees using a mulching machine is effective and creates a relatively instantaneous neat appearance, however, it is difficult to treat the cut stumps in a timely manner and the cut stumps are often difficult to locate amongst the mulched material. Regrowth from the remaining roots will be rampant and should be controlled with an herbicide application approximately six months after initial clearing.

5.0 REFERENCES

Identification and Control of Non-Native Invasive Plants in the Tampa Bay Area (Guide). Date Unknown. Hillsborough County Invasive Species Task Force. 48 pages.

National Park Service. 2002. Exotic Weeds I. Http://www.nature.nps.gov/wv/ipm/exweeds1.htm . 9 p.

Langeland, K.A. and Meisenburg, M. Professional Applicator’s Guide to Herbicides for Melaleuca Control. http://edis.ifas.ufl.edu/ag244 . 2 p.

APPENDIX UA

Invasive Species Management Elements

A1.1. Installation & Date: MacDill AFB, 3 October 2013

A1.2. Target Pest or Species: Brazilian pepper (Shinus terebinthifolius)

A1.3. Site: Throughout MacDill AFB

A1.4. Surveillance: Visual inspections

A1.4.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A1.4.2. Methods: Vehicular surveys, pedestrian surveys

A1.4.3. Frequency: Weekly

A1.5. Non-chemical Techniques: Physical Removal

A1.5.1. Responsible organization: 6 CES/CEVN, Natural Resources Program

A1.5.2. Type: Mechanical

A1.5.3. Methods: Three principle mechanical clearing approaches are used to remove invasive species at MacDill AFB: 1) direct extraction of the trees using a track-hoe or similar equipment, after which the trees are piled up to dry prior to disposal through burning or mulching; 2) grinding or shredding the trees using a gyrotrack or similar tree clearing equipment, after which the remaining tree stumps are treated with herbicide to kill the roots; and 3) hand cutting down trees using a chainsaw or similar equipment after which the tree material is mulched using a mechanical mulching machine.

A1.6. Chemical Techniques: Herbicide Application

A1.6.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A1.6.2. Basis for treatment: Most cost efficient method for controlling invasive species when compared to mechanical clearing. Cultural techniques are general ineffective for this species, although biological control shows promise but has not been attempted yet at MacDill.

A1.6.3. Control standard:

A1.6.4. EPA registration number(s) or refer to pesticide use proposal:

CAUTION

A1.7. Remarks

A1.7.1. Sensitive areas: Herbicides cannot be applied over water, so care must be taken with treating terrestrial invasive species that are growing along ditch lines, shorelines, and wetlands.

A1.7.2. Prohibited practices: None

A1.7.3. Environmental concerns: Spills or unintended release of concentrated herbicide material. All spills must be reported to 6 CES/CEVN within 30-days.

A1.8. Additional Comments (if necessary): None.

A2.1. Installation & Date: MacDill AFB, 3 October 2013

A2.2. Target Pest or Species: Lead Tree (Leucaena leucocephala)

A2.3. Site: Throughout MacDill AFB

A2.4. Surveillance: Visual inspections

A2.4.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A2.4.2. Methods: Vehicular surveys, pedestrian surveys

A2.4.3. Frequency: Weekly

A2.5. Non-chemical Techniques: Physical Removal

A2.5.1. Responsible organization: 6 CES/CEVN, Natural Resources Program

A2.5.2. Type: Mechanical

A2.5.3. Methods: Three principle mechanical clearing approaches are used to remove invasive species at MacDill AFB: 1) physical extraction of the trees using a track-hoe or similar equipment, after which the trees are piled up to dry prior to disposal through burning or mulching; 2) grinding or shredding the trees using a gyrotrack or similar tree clearing equipment, after which the remaining tree stumps are treated with herbicide to kill the roots; and 3) hand cutting down trees using a chainsaw or similar equipment after which the tree material is mulched using a mechanical mulching machine.

A2.6. Chemical Techniques: Cut stump, girdling, and foliar application

A2.6.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A2.6.2. Basis for treatment: Most cost efficient method for controlling invasive species when compared to mechanical clearing. Cultural controls have not proven effective for this species.

A2.6.3. Control standard:

A2.6.4. EPA registration number(s) or refer to pesticide use proposal:

CAUTION

A2.7. Remarks

A2.7.1. Sensitive areas: Herbicides cannot be applied over water, so care must be taken with treating terrestrial invasive species that are growing along ditch lines, shorelines, and wetlands.

A2.7.2. Prohibited practices: None

A2.7.3. Environmental concerns: Spills or unintended release of concentrated herbicide material. All spill must be reported to 6 CES/CEVN within 30-days.

A2.8. Additional Comments (if necessary): None.

A3.1. Installation & Date: MacDill AFB, 3 October 2013

A3.2. Target Pest or Species: Melaleuca/Punk Tree (Melaleuca quinquenervia)

A3.3. Site: Throughout MacDill AFB

A3.4. Surveillance: Visual inspections

A3.4.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A3.4.2. Methods: Vehicular surveys, pedestrian surveys

A3.4.3. Frequency: Weekly

A3.5. Non-chemical Techniques: Physical Removal

A3.5.1. Responsible organization: 6 CES/CEVN, Natural Resources Program

A3.5.2. Type: Mechanical

A3.5.3. Methods: Three principle mechanical clearing approaches are used to remove invasive species at MacDill AFB: 1) physical extraction of the trees using a track-hoe or similar equipment, after which the trees are piled up to dry prior to disposal through burning or mulching; 2) grinding or shredding the trees using a gyrotrack or similar tree clearing equipment, after which the remaining tree stumps are treated with herbicide to kill the roots; and 3) hand cutting down trees using a chainsaw or similar equipment, followed by chemical treatment of the cut stump, smaller tree material is mulched and left on site, while large trees are stacked and allowed to decompose naturally.

A3.6. Chemical Techniques: Cut stump, girdling, hack and squirt, and occasionally foliar application

A3.6.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A3.6.2. Basis for treatment: Chemical treatment is more cost effective than mechanical removal, and cultural control methods have not proven effective for this species.

A3.6.3. Control standard:

A3.6.4. EPA registration number(s) or refer to pesticide use proposal:

CAUTION

A3.7. Remarks

A3.7.1. Sensitive areas: Herbicides cannot be applied over water, so care must be taken with treating melaleuca which prefers to live in wetlands. Chemical treatment can only occur when no standing water is present on the site.

A3.7.2. Prohibited practices: Treatment in or over standing water.

A3.7.3. Environmental concerns: Spills or unintended release of concentrated herbicide material. All spill must be reported to 6 CES/CEVN within 30-days.

A3.8. Additional Comments (if necessary): None.

A4.1. Installation & Date: MacDill AFB, 3 October 2013

A4.2. Target Pest or Species: Australian pine (Casuarina spp.)

A4.3. Site: Sporadic presence along MacDill’s southern and western coastline

A4.4. Surveillance: Visual inspections

A4.4.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A4.4.2. Methods: Vehicular surveys, pedestrian surveys

A4.4.3. Frequency: Weekly

A4.5. Non-chemical Techniques: Physical Removal

A4.5.1. Responsible organization: 6 CES/CEVN, Natural Resources Program

A4.5.2. Type: Mechanical

A4.5.3. Methods: Mechanical clearing of this species is rarely accomplished because they are typically found in and around mangrove areas and the collateral damage to native vegetation does not warrant mechanical clearing. Occasionally the trees are cut down using a chainsaw. Cut trees are left where they fall to decompose naturally Immediately after cutting, the cut stumps are treated with herbicide to kill the roots.

A4.6. Chemical Techniques: Basal treatment, girdling, and cut stump.

A4.6.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A4.6.2. Basis for treatment: Chemical treatment is more cost effective than mechanical removal, and cultural control methods have not proven effective for this species.

A4.6.3. Control standard:

A4.6.4. EPA registration number(s) or refer to pesticide use proposal:

CAUTION

A4.7. Remarks

A4.7.1. Sensitive areas: Herbicides cannot be applied over water, so care must be taken with treating terrestrial invasive species that are growing along ditch lines, shorelines, and wetlands.

A4.7.2. Prohibited practices: None

A4.7.3. Environmental concerns: Spills or unintended release of concentrated herbicide material. All spills must be reported to 6 CES/CEVN within 30-days.

A4.8. Additional Comments (if necessary): None.

A5.1. Installation & Date: MacDill AFB, 3 October 2013

A5.2. Target Pest or Species: Cogon grass (Imperata cylindrica)

A5.3. Site: Throughout MacDill in open fields and along forest edges

A5.4. Surveillance: Visual inspections

A5.4.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A5.4.2. Methods: Vehicular surveys, pedestrian surveys

A5.4.3. Frequency: Weekly

A5.5. Non-chemical Techniques: Plowing, Disking and Scraping

A5.5.1. Responsible organization: 6 CES/CEVN, Natural Resources Program

A5.5.2. Type: Mechanical

A5.5.3. Methods: Mechanical removal of this species has not yet been attempted on MacDill because chemical treatment is cheaper and easier.

A5.6. Chemical Techniques: Foliar application.

A5.6.1. Responsible organization: 6 CES/CEVN, Natural Resource Program

A5.6.2. Basis for treatment: Chemical treatment is more cost effective than mechanical removal. Prescribed burning is ineffective, and no biological controls are known.

A5.6.3. Control standard:

A5.6.4. EPA registration number(s) or refer to pesticide use proposal:

Trade Name Element 3A (EPA 62719-40), signal word DANGER;

Trade Name Round-up Custom (EPA 524-343), signal work CAUTION

A5.7. Remarks

A5.7.1. Sensitive areas: None

A5.7.2. Prohibited practices: None

A5.7.3. Environmental concerns: Spills or unintended release of concentrated herbicide material. All spills must be reported to 6 CES/CEVN within 30-days.

A5.8. Additional Comments (if necessary): None A6.1. Installation & Date: MacDill AFB, 3 October 2013

A6.2. Target Pest or Species: Water hyacinth (Eichornia crassipes)

A6.3. Site: Mostly…