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RESOURCE MANAGEMENT PLAN 6/85 Suite 201 1300 West Lantana Road Lantana, Florida 33462 Phonel (305) 533-0902 RITECO DEVELOPMENT CORPORATION June 6, 1985 City of Boynton Beach Attn Carmen Annunziato POBox 310 Boynton Beach, FL 33435 Dear Carmen Enclosed is the Resource Management Plan for the Boynton Beach Park of Commerce Scrub Tract After you have reviewed the Plan, please call me with your comments Sincerely yours, ~ Wade Riley Vice President WR/gd cc Nate L Adams, II enclosure Report on the Prop:>sed Resource Management Plan on the Boynton Beach Park of Canmerce Scrub Tract, Palm Beach County, Florida. Dick Roberts, Biologist P.D Box 1246 Hobe Sound, Florida 33455 Ixm Richardson Ecological Consultants 8909 Hooley Court Tampa, Florida 33614 As per a developnent order prop:>sed by the Treasure Coast Regional Planning Council, the disappearance of sand pine scrub habitat within the region has caused concern for the remaining reITU1ants and the preservation of its tmique plants and animals. In an effort to preserve the largest contiguous area of sand pine scrub, the developer of this property, the City of Boynton Beach, and the Treasure Coast Planning Council staff have agreed to set aside the 35 acres east of High Ridge Road and north of 22nd Avenue (a p:>rtion of Yilidl is mature sand pine scrub) lD'ltil such time it is ascertained whether the 40 acres that is west of High Ridge Roa::1 and north of 22nd Avenue can be restored to a satisfactory diversity of scrub habitats and species. The latter site has suffered deterioration due to sp:>ra::1ic understory clearing and livestock qrazing, but is one manageable piece of property and still supp:>rts a number of scrub plants and animals of regional concern. In the agreerrent, the second site (40 acres) would be reveqetated and rranaged up to a period of 3 to 5 years during which it will be exmpared with the 35 acre site. 'Ihe management period is now extended to a maxinum of 12 years. If and Yilen the managed site does achieve the natural diversity and the tmique species cornrrensurate with the 35 acres, then the 35 acre site will be released for developnent and the 40 acre site will becane a preserve for indemic flora and fauna. Annual rep:>rts concerning the progress of the 40 acre site will be sent to thp City of Boynton Beach, CNR and TCRPC.. Also, it was agreed that during the 12 years of mitigation no develqment will occur in the natural scrub site east of High Ridge Road. The pJrpose of this report is to define the prop:>sed management philosophy for preservation of the 40 acre site and establish methodology for the next 12 years. BASIC MANAGEMEm' PHILOSOPHY 'Ihe objective of the resource rranagerrent plan is to restore the subjected piece of property to a representative sample of an original Florida ecosystem and also increase its natural diversity RESOURCE MANAGEMEm' 'l11e predominant plant canmuni ty is sand pine scrub. It occurs at eleva- t ions approaching 15 to 26 feet and shows evidence of early Pleistocene soorelines by occurring in a dune ridge. 'l11e scrub is a very xeric type of plant canmmi ty and is adapted to the dry and relatively sterile sand of the old dunes As soch, Page 2 species living within this system are adapted to survive under conditions of extreme drought and low soil fertility associated with well-drained sands, as well as periodic fire Sand pine (Pinus clausa) is the dominant tree and is usually found in closed canopy situations of mature stands as shown north of 22nd Avenue. The characteristic woody understory species adapted to xeric conditions of the scrub include various scrub oaks, saw palmetto, and rosemary. Fire generally does not enter sand pine stands except when the fuel levels are high and weather conditions severe This often leads to very hot crown fires, hot enough to kill the sand pines and other vegetation. However, fires are necessary to regen- erate sand pine forests, and it reduces hardwood competition, triggers the release of sand pine seeds, and improves the seedbed If fire is excluded from scrub, the sand pines eventually will die of old age, approximately 80 years, and the habitat may ultimately grow into a xeric oak forest. However, if a fire is carried through the area, the mature trees are killed and the new seeds begln the cycle again. This plant community also contains many endangered, threatened, and endemic plant and animal species that depend on this type of habitat for survival. Some have different environ- mental requirements even with the same plant community, and will require different management objectives if they will be retained on- site MANAGEMENT PROCEDURES In our stated objective for the management of this property, there are major responsibilities for the long term preservation of the vegetation, wlldlife, and soil, plus the area's natural resources In this role, the following comments are reasonable judgments as to the management "state of the art", so that the area will be sufficiently protected for the future and not just short-term realities Assessment of impact and management recommen- dations are based on field observations, comparison to past records, and a review of pertlnent literature. Fire Management - Fire has a necessary historical role in the perpetuation of sand pine scrub and maintaining its diveristy of vegetation. Man's efforts to suppress fires and the development of firebreaks provided by human activity (roads, etc.) have created the need for instigating prescribed burns to maintain scrub In addition, the burning of the areas at different times will also help promote a diversity of different age stands of vegetation. Page 3 This plant community appears to be adapted to a 30 to 40 year cycle This documentation is largely established as a theoreti- cal ideal time sequence for Rosemary (Ceratiola ericoides) and Sand pine (Pinus clausal as both can be aged and their life histories have been well studied. A preliminary survey of 27 randomly selected trees, starting near the south end of the 40 acre parcel and working north, were cored and the age of each tree determined by counting growth rings. It was easily summarized that even with this small sampling, the older trees were located on the southern end of the property (oldest approximately 50 years of age) and the youngest trees were on the northern end of the property (approximately 15 years old). Using this data, which will have to be further defined, the scrub commu- nity was divided into zones that will be used for future management purposes to promote a diversity of different age stands of scrub. Although somewhat theoretical and the fact this will have to be further defined in the field with more core samples and field observations, a preliminary map has been attached. This information will also be based on the ongoing census of the endangered plants and animals. As the study continues to develop, a better picture of all the management zones will appear. Of course, a fire model will be formulated to judge the effects of the thermal dynamics of a proposed fire. This will include the amount and combustability of fuels, required moisture content, air temperature and humidity, desired wind speed and direction, and any other changes that may alter the fire's progress. A defined fire prescription will be developed for the site that will include good smoke management. However, most of this data is site specific and will have to wait until the size, location, and special problems for the preserved piece of property is better defined. Also, the plan will address the need to maintain the ecological diversity of the scrub. Instead of burning all the fire- adapted communities at one time, the site selected for preservation will be partitioned into zones that will be managed and burned separately. Thus, the wildlife will be able to use recently burned tracts, as well as formerly burned areas. If burning turns out to be a non-acceptable means for main- taining the existing scrub due to smoke management or excessive explosive fuels, the mechanical means, such as what is currently being utilized at Ocala National Forest, will be instituted. However, this is only viewed as a last resort because of soil disruption and the compaction it causes. Page 4 Threatened Plants - All native plants within the site are of interest and worthy of protection, however, the following is a list referenced from the Florida Committee on Rare & Endangered Plants & Animals, Florida Department of Agriculture and Consumer Services, and the U.S. Fish and Wildlife Service (see the DRI Assessment Report on this property for more information) Scrub Mint Indian Pipes Sand Spikemoss Conradina grandlflora Monotropa brittonii Selanginella arenicola All of the above listed plants except Indian Pipes are largely noted on this list because of the limited expanse of sand pine scrub vegetation, and the devestation being inflicted upon it by the development of business areas and residential housing along the southeast coast of Florida. It is suggested that Scrub Mint and Sand Spikemoss respond favorably to fire by seeding into the new burned over areas. Also, Scrub Mint and Sand Spikemoss are somewhat intolerant of heavy shade and do best in clearings or open areas Crown closure of the overstory should be suppressed around these specles. Any area within the proposed preserved site that will require restoration because of past impacts (old trails, dump locations, etc.) will use the native plant species of that indicated community. Threatened Animals - Several reptiles and a mammal are considered highly adapted to scrub (i.e , reaching their maximum population levels or found only within this habitat) and deserve further comments. All are referenced in the Florida Committee of Rare & Endangered Plants & Animals book and have been observed by qualified field observations: Gopher Tortoise Indigo Snake Florida Mouse Gopherus polyphemus Drymarchan corais peromyscus floridanus The Gopher Tortoise is known from several plant communities all of them being well-drained, having sandy soils, and containing an abundance of grasses. This would clearly indicate that they would be more abundant in early successional stages of sand pine scrub than in the more advanced, closed canopy, thick understory conditions. It has been reported at the Fifth Annual Gopher Tor- toise Council Meeting (November 9-11, 1984) that tortoise densities average 10.4 to 20.4/ha , but may reach a density as high as 28 to 33/ha. where predation is minimized and habitat is ideal. Page 5 If the present census of 36 animals is correct for the total 540 acre piece of property, then using at least 9 acres of the 40 acres (the lowest density, 10.4/ha.) should be maintained and managed for Gopher Tortoises. Proper management would be either to burn or chop (manually, not with heavy machines) on a yearly cvcle. The Indigo Snake is not restricted to scrub habitat. When it is found in this habitat, the shelter and moisture provided by the Gopher Tortoise burrows is a critical factor. The management of scrub to provide more diversity of age stands and younger sites would tend to favor these two above mentioned animals. The Florida Mouse is a threatened species found almost en- tirely within the scrub and generally associated with Gopher Tor- toise burrows. It has been generallly more often trapped in the early stages of this plant community that have low shrub height and thick cover than the more mature stands (Roberts, unpublished manuscript). Like the above animals, this would suggest that this habitat should be burned on a more frequent schedule and have natural corridors open for animals to move from one area to another. Because of the negative impacts (genetic pool disruption, stress to existing populations, disease transmission, etc.) the re- location of the above species to an off-site location would not be desirable. Exotic Plants One of the most serious threats to any native plant community in South Florida 1S the invasion of exotic vegetation. Exotics can modify normal ecological processes or relationships, including predator-prey and herbivore-plant relationships, nutrient and energy cycles, and soil-building and erosion processes. It has also been shown that the general stability of our natural communities is also reduced. One exotic plant species is an existing threat, namely Brazilian pepper (Schinus terebinthifolius) and has been noted within the area of study. The permanent removal of exotics must be completed with the reforestation of native plant species relating to that par- ticular plant community. Roads and Trails - Although some damage has occurred by the creation of roads and trails on the site, it has been left largely unscarred. The planned use of preserved sites should restrict the construction of fire roads to as few as possible and restrict research vehicular useage (by Mytinger and Roberts in their "E.I.S. of Military Reserve and National Guard Activities on a Portion of Jonathan Dickinson State Park"). Once these areas are impacted, their rate of recovery is slow and the entire community may be affected. P~e 6 Prior to any management manipulation, at least 4 permanent line transects will be established on the 40 acre site, as well as on the 35 acre site Along each 100 meter line, a rrodified line intercept method will be used (rrainly looking at frequency) to establish the baseline information. They will be resurveyed annually to see if the stated objectives have been readled. Also, any landscaping that will be aocornplished in this interim period will obtain the same percentage of veqetational frequency as the control. 4/85 1/ I {, ' I :,~ "C- ~ I .( MU~K \ , ~ / ,/ J .i / _/ --~,~. I -V ryr · .}[$IN~'~K) ~ ,i PI.!I (1 , ~? I I # q,( i / '.- \1 , A ' ~.t . ! s (N~- ~UC;~~) I \ I ,~ I '\ ( 1 ~ ,,-''tk. MVCr , " V'l 7 ':__ l ) ~ '4 b ...---- i 7 4.6 ..... fO // ""-</ (Ie, \ , J.c' ) >1 o I ;; } i , , 9 ; \ c' n ! ' /,/' I ,--, ~(./"," \ \' ~'-2'\\ --.---. J"'" 9 I . '-"" \ . 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