- Email: [email protected]
Wildlife habitat as an integral component of a planned unit development
Urban Ecology, 3 (1978) 171-187 o Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands
WILDLIFE HABITAT AS AN INTEGRAL UNIT DEVELOPMENT
171
COMPONENT OF A PLANNED
JAMES R. VILKITIS Carlo&,
Sinton,
and Vilkitis,
Inc., Amherst,
Mass. (U.S.A.)
(Received 14 December 1976)
ABSTRACT Vilkitis, J.R., 1978. Wildlife habitat as an integral component ment. Urban Ecol., 3: 171-187.
of a planned unit develop-
A planned unit development (PUD) for 8800 single family and multiple dwellings was designed and is being implemented to be consistent with the biological resources of the site and ecological parameters set by land form and function. Twenty-one disciplines within the biological, physical and social sciences were involved in the analysis and planning of the project. The guiding principle of the effort was to create an environment for people which would provide a wide range of resource uses and at the same time assure that the function of the living landscape upon which those resource uses are dependent would be maintained as an integral part of the developed community. Tbe underlying philosophy of the PUD was to enhance and maintain natural habitat for wildlife and to improve the aesthetic character of the landscape through diversifying open space, plantings and waterways. The plan attempted to create as many different and indigenous habitat types and mixes as possible within and between development areas. Upon completion of landscape renovation none of the indigenous species of wildlife known to inhabit the site were displaced due to the total destruction of their habitat. Of the four types of wildlife environments identified (forest edge, wetlands, savanna, and swamp forest), three were enhanced; the swamp forest was not altered and was set aside as a natural preserve. Forest edge was increased through the creation of adjacent non-symmetrical canals. In addition, green beltways were created along the canal system to increase the water/land habitat interface, and to serve as temporary water storage during critical storms. Wetlands and open waterbodies were renovated to create deeper water for a fishery, create additional shoreline for wildlife habitat and improve the visual quality through diversity. The uplands and improved pasture (savanna) were the areas chosen for development. Monitoring programs for the ground water and biological systems have been established and will be interpreted annually for the life of the project to determine whether the local ecology is being significantly altered. Of the 3355 acres involved, approximately 1510 acres (45%) were left as natural preserves. Plantings for landscape renovation involved only indigenous species that would not require continued maintenance.
INTRODUCTION The research
and planning
aspects
of this project
were initiated
in July
172
1973 and completed by January 1974 for the Covington Development Company (Vilkitis, 1974), managing partner of Lake Padgett Pines, to fulfill the requirements of the Application for Development Approval, Florida Law, Section 380.06, for a development of regional impact. The Master Plan which resulted from this effort is currently being implemented. Monitoring of the ground water and biological systems will continue throughout the life of the project. The Lake Padgett Pines Development is located in the west-central part of Florida (U.S.A.) in Pasco County in the town of Land O’Lakes, approximately 19 miles north of Tampa (28” 1500’N, 82” 26.25’W). The area is subtropical with a mean annual temperature of 72.3” F; the prevailing wind is from the east at a mean velocity of 8.9 mph. Annual rainfall averages 51.57 inches with the heaviest rainfall (31.03 inches) occurring from June through September. Upon completion (within 10 years), the 3355 acre development would include 8800 single family and multiple dwelling units housing 30145 residents, including approximately 7200 children of school age and 4220 persons over 60 years. It will contain recreation areas, open spaces, nature preserves, schools, and commercial facilities. All earthwork for the development was completed by January 1974; the preliminary plat for the first 151 lots was filed in November 1975. The site is contiguous with the Cypress Creek Swamp on its east border, and contains approximately 1000 acres of swamp forest. The majority of merchantable timber and source trees for turpentine production were removed prior to World War II. The uplands and pasture (savanna) have been maintained (mowed and fertilized) for cattle grazing since 1938; wetlands were excavated to provide open water for cattle. Dominant vegetation in the savanna consists of cypress heads (Z’uxodium distichum), eucalyptus (Eucalyptus spp.) and longleaf pine (Pinus palustris); there is no codominant or lesser woody species. Wildlife inhabiting the area consists of species associated with the swamp forest, forest edge, savanna, wetlands and lakes (Table I). The majority of species known to occupy the site are associated with the forest edge and wetlands. A variety of wetlands, canals and ponds (a total of 18) is scattered throughout the savanna. Prior to implementation of the planned unit development (PUD) a number of environmental issues (natural, social and political) had to be approved by state, regional and local governmental authorities. All aspects of a development with regional impacts had to be addressed and resolved in the context of the regional community. Fifteen governmental agencies were involved with the project. Twenty-one disciplines within the biological, physical and social sciences were involved in analysis and planning of the project. Our primary objective was to design and implement a PUD which would be consistent with the natural resources of the site and ecological parameters set by land form and
173
TABLE I Birds, mammals, reptiles and amphibians found on the site Birds 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
Red-headed woodpecker Yellow shafted flicker Cardinal Meadowlark Killdeer Cattle egret Bobwhite White ibis American egret Redwinged blackbird Common gallinule Water turkey Marsh hawk Great blue heron Little blue heron Mourning dove
Melanerpes ery throcephalus Colaptes auratus Richmondena cardinalis Sturnella magna Charadrius vociferus vociferus Bubulus ibis Colinus virgianus Eudocimus albus Casmerodius albus egretta Agelaius phoeniceus Gallinula chloropus cachinnans Anhinga anhinga Circus cyaneus Ardea herodias Florida caerulea Zenaidura macroura
Mammals 1. Nutria 2. Armadillo 3. Marsh rabbit 4. Fox squirrel 5. Eastern cottontail
Myocastor coypus Dasypus novemcinctus Sylvilagus palustris Sciurus niger Syloilagus floridanus
Reptiles 1. American alligator 2. Florida mud turtle 3. Striped mud turtle 4. Stinkpot 5. Florida water snake 6. South Florida swamp snake 7. Eastern garter snake 8. Florida cottonmouth
Alligator mississipiensis Kinosternon subrubrum steindachneri Kinosternon bauri palmarum Sternothaerus odoratus Natrix fasciata pictiventris Seminatrix pygaea cyclas Thamnophis sirtalis sirtalis Agkistrodon piscivorus conanti
Amphibians 1. Greater siren 2. Bullfrog 3. Peninsula newt 4. Florida cricket frog 5. Florida chorus frog
Siren lacertina Rana catesbeiana Notophthalmus viridescens piaropicola Acris gryllus dorsalis Pseudacris nigrita verrucosa
function and which at the same time would conform to all environmental, social and political legislative constraints. We recognized that it was necessary to alter the area from its prior physical form and biological character in order to accommodate any significant human activities. The problems were those of transforming physical and biological alterations to the land- and waterscape into new opportunities for
habitat. We wanted to create an environment which would provide a wide range of resource uses for man and at the same time assure that the functions of the living landscape upon which those resource uses depend were maintained. The Master Plan was designed so that all parts of the community would benefit from the physical presence of preserves, green open space and water bodies. Once the Master Plan was implemented, dwellings and their support facilities could arise in full recognition of the dual necessity to provide for man that which man must make and to provide for the continuance of a sound ecological base for that which nature must provide. We believe that this development will satisfy the physical and social needs of its inhabitants, as well as provide for the maintenance of biological life support systems which give all of us our required resources and rich diversity of aesthetic experience. Only the major biological and physical attributes of the interdisciplinary resource analysis that dealt with the wildlife-habitat-man interaction are presented here. The conceptual design for project implementation was site development planned in a fashion that would maintain and protect the existing ecosystem. The plan integrated wildlife and landscape management criteria within the restrictions set by governmental agencies, existing land use and biological and physical parameters of the site. The intent was to optimize favorable contacts between wildlife and urban residents by providing a continuum of natural habitats (waterways, green beltways, etc.) that would insure diversity of both plants and animals. The diversity within the continuum (i.e., land and water interfaces) would insure visual and habitat quality. The criteria used to develop and implement the plans were as follows: -- Habitat is a complex matrix involving the interaction of plants, animals, man, and physical factors; alterations involve a simultaneous interaction of the parts. ~ Potential land usage can be interpreted from the biological and physical attributes of the landscape; only those that offer the highest potential for alternative resource use would be considered for development. - In general, the more stable biological systems exhibit greater diversity of plant and animal species; restoration will insure maximum habitat diversity. -- Trophic levels are interconnected within biological communities, the base of which is natural vegetation. Therefore indigenous vegetation would be used for planting disturbed areas to maintain natural stability within the biological community. --- Wildlife populations are renewable resources that perpetuate themselves indefinitely if their habitat contains the necessities for completion of a life cycle. - Wildlife habitat for resident species is a function of food, water, escape cover, and reproductive areas in close proximity to each other. - Variety and interspersion of different vegetation types determine
C.rloz*l,
Fig.1.
-
Major land categories
s,n,an
A
“llkltl.
of the local and regional
1°C..
Anlher*f.
--.lL-l M*
landscape.
wildlife abundance; maximum variety and interspersion are essential to habitat restoration and enhancement. Wildlife management strategies are site specific; they must be suited to particular landscape(s) and wildlife population(s). Only indigenous wildlife
176
:LORlDlAN
AOUIFEA
iattesian
V
Fig.2. Landscape continuum.
species known to inhabit the site would be considered. Natural invasion of species not known to occupy the site might occur, but would not be sought. - The extent of landscape alteration and rehabilitation determines the visual quality of the site and the kinds and densities of wildlife present. All altered landscape would be restored to maximum species diversity and stability of the natural system. PROCEDURES
The evaluation process proceded from a general assessment of the region to an in-depth analysis of the development site. Through aerial photographic interpretation and field reconnaissance, land categories of the local and regional landscape were identified and mapped. The major categories were upland vegetation (forest), open land, pasture, open water, wetlands, swamp forest and citrus grove. Those found on the property are presented in Fig.1.
177
A profile of the landscape continuum aided in determining the interrelationship and importance of the land uses within the region to physical factors (Fig.2). The continuum provided the basis for formulating an experimental research design to assess the important physical and biological attributes of the land categories of the development site. The following attributes were analyzed. (A) Vegetation. - Proportional random sampling of forest associations for the dominant (above 6” dbh*), codominant (between 1” and 6” dbh) and lesser (below 1” dbh) woody species was undertaken to determine (1) species composition; (2) relative density (maximum total 100); (3) relative frequency (maximum total 100); (4) relative dominance (maximum total 100); (5) importance value: sum of quantities 2,3, and 4 above (Phillips, 1959); (6) growth rates of major dominant woody species determined by multiple linear regression techniques. (B) Soils. - Stratified random sampling of soil profiles for physical and chemical characteristic to determine (1) texture; (2) organic content; (3) calcium, sodium, phosphorus, and potassium concentration; (4) hydrogen ion activity (pH); (5) erosion potential (wind and water). (C) Wildlife. - Delineating potential wildlife habitats based on (1) land use history and existing vegetation; (2) major resident and transient wildlife species known to inhabit the area; (3) threatened species unique to the development site and region; (4) vegetation diversity. (D) Open water. - Stratified random sampling to determine (1) general morphology of water bodies and depth of organic sediment; (2) turbidity (materials in solution and suspension); (3) productivity (turbidity and algae); (4) major fin fish; (5) minimum and maximum temperature (bottom and top); (6) dissolved oxygen (bottom and top); (7) hydrogen ion activity (pH); (8) total phosphates (meta and ortho). (E) Ground water. - Assessment to determine (1) geologic formations; (2) principal aquifers and confining layers; (3) ground water movement; (4) best source of potable water; ____ *dbh refers to the diameter
of a tree at breast height (4.5
ft.).
178 (5) potential yield of aquifers containing potable water; (6) water quality; (7) impact of ground water diversion of 3.5 million gallons per day (mgd) from major aquifer on surface water bodies and water table; (8) potential of salty water encroachment. (F) Land use. - To determine (1) history of land use; (2) potential utilization. The baseline data (including that which dealt with the social and cultural sciences) after analysis was integrated into a landscape management plan for the PUD through an interdisciplinary impact assessment process. At this stage the pros and cons of development on specific sites were weighted as to their potential impact on the physical and biological features of the landscape. Through this integrated assessment, sites were evaluated qualitatively and quantitatively in terms of their ability to sustain development, and subsequently were categorized in terms of their potential uses. Our “functional landscapes classification” system was patterned after Odum (1969) and included production, protection, compromise and urban-commercial environments. The components represent, in general, the spectrum of ecological conditions found anywhere. Productive environments are growth systems characterized by rapid turnover of resources, short life cycles, high production rate and relatively simple life forms; these systems cannot be subject to long or varied stresses. Protection environments are characterized by a slow turnover of nutrients, rather long life cycles, and large and more diverse life forms; they can tolerate considerable stress without total collapse. According to Odum, compromise environments are mixed systems of protection and production environment. The compromise environment on the site consisted of upland pine forest and improved pasture; there were no protection environments included in our classification. Urban-commercial environments which are ecologically non-vital areas created by man did not exist on the landscape prior to development. In general, the natural and physical features of the functional landscapes set the basic parameters by which development planning proceeded; that is, the exact juxtaposition of housing units, structures, roadways, etc., in the natural environment. The functional landscapes identified on the site are presented in Fig.1. RESULTS
The water table altitude controls the major biological and physical attributes of the site and related local ecology. It receives recharge from precipitation and runoff and the discharge of the Floridan aquifer under artesian conditions. The altitude of the water table controls (1) diversity and productl vity of flora and fauna in the swamp forest and wetlands; (2) water levels in existing canals and lakes; and (3) the growth rate of dominant indigenous vegetation in the pasture and upland areas (Fig.2).
179
The PUD upon completion would require on-site removal of 3.15 mgd of potable water from the Floridan aquifer and would cause the water table in the shallow aquifer around the well field to drop one or two feet. To further complicate the ground water situation, an independent municipal plan (unapproved by state or regional water control planning agencies) to withdraw an additional 55 mgd from an adjacent site is being undertaken. This plan, when completed, will cause severe local drawdown, critically altering existing shallow ground water levels and destroying the existing biological character of the communities that inhabit the area and region. Prior to any development, surface runoff discharged naturally through the northeast and southeast corners of the property into the swamp forest as fast as the drainage basin would allow (Fig.1). There appeared to be no alteration of the biological communities from this discharge. However, upon project completion there would be a substantial increase in surface runoff due to roads, structures, parking lots, etc. The engineers estimate that a 25-year storm would generate a peak flow of approximately 700 cubic feet per second (cfs) which would discharge into Cypress Creek Swamp quickly without flood control. This volume of water would disrupt the local biological, physical, and cultural resources and add to regional flood conditions from streams draining the eastern and southern portion of the swamp. Existing water bodies (90 acres) consisted of ponds, canals, and intermittent wetlands. In general the ponds and canals were shallow, relatively unproductive bodies (based on secchi disc, phosphates, and pH indicators) with few fin fish. There was low primary production and little nutrient circulation. Wetlands with less than 3 feet of water were weed choked due to eutrophication caused by grazing cattle; those with more than 3 feet of water, which inhibited grazing, had no bottom vegetation. The pH (average 5.8) was well below the range (6.6 to 9.0) that produces the best growth rates and reproductive success of the indigenous fin fish. The temperature (top and bottom), dissolved oxygen, and total color (suspended and dissolved materials) were suitable for supporting high fish populations. Shoreline vegetation was sparse or nonexistent, since the pasture and open areas of the upland forest were mowed to the water’s edge to maintain grasses and improve access for stock. Low primary productivity was attributed to the morphology of the water bodies, and to low pH and lack of available nutrients in the water and adjacent land. The fine, sandy (above 65% by volume) soils allowed lateral movement of shallow ground water to the canals and lakes. The soils were acid (pH 5.2 to 5.7) with low natural fertility (lack of weathering) and low moisture-holding capacity. The low water-holding capacity of the soils poses a problem to terrestrial plants when the shallow ground water level is lowered below their effective rooting zone. The 3.15 mgd on-site withdrawal would cause the surface ground water level to drop to below this zone only within several hundred feet of a pumping well; the off-site withdrawal of 55 mgd has potential to lower the surface water level below this zone over the entire property.
180
The soil productivity of the site, reflected by nutrient capabilities within a forest classification was, in general poor to fair. They were, however, classified in order of their relative productivity within the site. The area with the best soil for growing vegetation was the ecotone between the wet and upland areas; the swamp forest and upland forest soil was good to fair, and the open land and pasture was the poorest. Three functional landscapes were identified on the site, and were defined as follows: .- Production environments include fresh permanent water at least 3 feet deep, and wetlands with permanent or intermittent water less than 3 feet deep. -- Protection environments include cypress heads in the pasture, swamp forest that experiences periodic flooding, and the hardwood-cypress forest ecotone between the pasture and swamp interface. -- Compromise environments include the open pasture, pine stands in the upland areas, and the hardwood stands in the open pasture. IMPLEMENTATION
Based on the preceeding assessments, three major development decisions were made. First, in order to maintain and perpetuate the delicate balance between the ground water and biological systems, water would have to be added and maintained on the site to compensate for ground water withdrawal. Second, development areas would include only the upland area and pasture (compromise environment), since they had the least biological diversity, and had been continuously altered by man in the past and could sustain the greatest amount of disturbance with the least detrimental effect on the total environment. Third, the swamp forest (protection environment), due to its unique biologic character in the site and region, was excluded from development. To maintain the balance between the ground water and biological systems, water would be added and retained on the site for maximum ground water recharge. The additional water would come from runoff and tertiary treated effluent (2.4 mgd). It would be detained on the site in lakes and through a system of interconnecting canals. The canal system would serve to: -- return and retain (through a system of weirs) the water that has been used from the Floridan aquifer in order to allow adequate time for it to percolate through the soil and recharge the shallow aquifer; -- maintain the water table altitude at its normal level; quickly drain water generated from critical storms off the landscape; -- direct storm water to natural long-time drainage areas so as to prevent erosion and water damage; -- allow maximum water retention time, through controlled outflow so that the water would purge itself through natural processes of detergents, solvents, and other chemical agents that are not immediately biodegradable;
181
Housing
+ Indigenous
Plantings
.stabilize
canal
.enhance
wildlife
.discourage .native
plants
on
1 T3
Slope
bank habltat
access require
to
water less
maintenance
Fig.3. The canals and green beltways are located next to the existing forest edge and serve as flood control devices. They were designed to serve as green beltways and as separators for the forest edge. Periodic weir dams will allow for fisheries management. Where length permits, flat-bottom boats can be used for water-based recreation.
- create new and diverse habitats for aquatic and shoreline wildlife species,
and provide recreation and nature study opportunities; --- act as a buffer area by limiting access to the contiguous swamp forest. The lakes would function as: --~-storage areas for water generated from storms and runoff; - polishing lagoons for temporary storage of storm and tertiary effluent; - a fishery providing additional shoreline and water habitat for wildlife; - additional surface water for recreation. Approximately 3 million cubic yards of earth were excavated to create 350 acres and improve 90 acres of open water; a total of 440 acres. The earth was taken from areas adjacent to the forest, around ponds, and along natural and man-made drainage areas. The land disturbed involved approximately 410 acres of pasture, 28 acres of wetland, and 2 acres of forest. All earth removed was used to fill low lying areas in the uplands and pasture that flooded temporarily during heavy rains. The canals and adjacent green beltways were designed with a series of weirs to control water levels at the 25 year flood level (1345 acre feet) for slow discharge into the swamp forest. Under natural conditions a 25year storm would have a peak flow discharge of 700 cfs; this would be reduced to 75 cfs through the canal and weir system. Bottom discharge provided maximum nutrient circulation for use by
Fig.4. The swamp forests in the eastern areas of the property are fragile and easily upset by heavy development. The canals will buffer them from the impact of the residents by limiting access, while at the same time allowing residents to live in close proximity.
the biological systems. The water levels in the canals would correspond to that which would be expected under natural local climatic conditions. Emergency popoffs were designed for storms greater than the 25-year flood. Initially the site served as a discharge area for ground water in the surficial aquifer. The new canals and lakes coupled with ground water removal would initially cause a drop in the water table; however the water added to the canal system would increase its head and eliminate any discharge from shallow water table formation into the canals and lakes. A green beltway with a 1 : 3 slope, 25 to 30 feet in width, adjacent to the canals but lower than upland development would serve as temporary storage for excessive runoff for ground water recharge and later release (Fig.3). The canal system would also assure, by limiting access, that the swamp forest would not be disturbed (Fig.4). This isolation would provide opportunity for the wildlife species associated with the swamp community to perpetuate themselves. Plantings of 60,000 indigenous shade trees were initiated during 1973 along the forest edge and periphery of the green beltway to stabilize canal and pond banks while enhancing wildlife habitat. Species chosen were those that would meet existing environmental conditions, rather than those that would require alteration of the environment to meet species requirements. Plantings were strategically placed to discourage indiscriminate human access to the canal (Fig.3), to maintain a natural outdoor-type experience for those recreating on the water, to protect wildlife habitats, and to limit recreational use of the canal system.
Waterbodies and wetlands were altered to increase shoreline and vegetation diversity to enhance the potential for wildlife use and fish production. Shallow wetlands with a deep organic sediment were not altered. Those near open water with a sandy substrate were deepened and/or widened (Fig.5). Shorelines were non-symmetrical to increase edge. A gentle slope was created near the shore for both waterbodies and wetlands and planted with indigenous species of plants to control access and improve habitat. Once the development is completed, walkways would be constructed near and/or over them; their location would be such that there would be minimal disturbance to the vegetation and wildlife (Fig.6). The canals and open water were designed to serve not only as havens for wildlife and water detention areas but also as a fishery (Fig.7). To mitigate the problems associated with the low aquatic productivity (pH and water depth) and the turbidity caused by the creation of the canals and deepening PLAN -“New
Option
SECTION ” ,ew
1 higher
Option
Fig.5.
fish
production
2
Alterations
in waterbodies
and wetlands.
Fig.6. Proposed treatment for existing wetlands includes clearing and deepening some areas near open water. Reducing steep profiles near banks to improve shore bird habitat, and constructing a walkway and overlook system in some of the more likely developed wetlands for outdoor recreation and education experience.
Green seltway
Wew Dam lbttom
Fig.7. lation
The management of weir dams.
Swamp
on Canal
Forest
Release
of canals for use as a fishery
becomes
prossible
through
the instal
of the waterbodies, the following procedures were implemented: - Prior to water and wetland improvements, the upland area was treated with 50 pounds of hydrated lime per acre. The plan was to slowly increase the pH of the water bodies through leaching to approximately 7.0 without causing sudden stress to the existing aquatic biota. The higher pH would allow the density of microscopic plants and organisms to increase without directly fertilizing the waterbodies. Fertilization was not recommended due to the continued maintenance required. The circulation of existing nutrients was increased by requiring all weirs to have bottom releases. This allows nutrients coming into the system from the landscape to be continuously circulated. .-- To inhibit the growth of undesired submerged aquatic vegetation, a problem which is characteristic of subtropic waters, the depth of the canals
185
Development
Housing Commercial
II
Recreation
=
Circulstwn
=
Natural Preserves Forest. Open
Wetland Water
Natural
Canals
Drainatte to Swamp & Greenbelt
a
Ez3 A
m
LAKE Land
0’
PADGETT
PINES.
Lakes.
Florida
Carloxzi* Fig.8. Master Plan for the site.
Sinton
A Vitkitis
MASTER
Dec.
PLAN
10. 1973
U.S.A. Inc..
Amherst.
Ma
USA
186
and ponds was increased to between 5 and 8 feet (Fig.5). The effective light penetration for the waterbodies measured with a Secchi disc was approximately three feet. By maintaining a depth greater than 3 feet, problems of managing submerged aquatic vegetation were lessened. -- Water turbidity caused by construction was eliminated by the application of approximately 500 pounds of gypsum per acre of water surface to flocculate suspended sediments. Gypsum is chemically neutral and can be applied immediately after dredging at any time of the year. Once the proper depth was obtained and the turbidity eliminated, stocking of mature 1 year old bass (Micropterus salmoides) at two fish per acre was recommended. Thereafter, the fishing management strategy to maintain a well structured population was to remove all fish caught, large and small since returning small fish disturbs the population balance. Wire waste fish baskets on swing poles adjacent to the swamp side of the canal would be provided for disposal of unwanted fish. The baskets would be designed to allow all scavengers easy access to recycle biomass. The Master Plan for the site illustrating all the development strategies is presented in Fig.3 To assure that the delicate balance between the shallow ground water and biological systems is maintained, a continuous monitoring program was established. Shallow ground water observation wells located in key areas on the site were equipped with continuous ground water recording devices. Trends in ground water levels are evaluated quarterly. In addition, it was observed that certain dominant upland vegetation had their lower root systems at the water table. It was established over a 15-year period that the growth rate (radial increment) was a function of ground water level fluctuations. Over 50 trees throughout the site that exhibited radial growth increment with ground water fluctuations were fitted with dendrometer bands. Results of their increment are assessed annually to determine if their growth falls within established confidence limits. ACKNOWLEDGEMENTS
The Master Plan for the Lake Padgett Pines Development was the result of a comprehensive interdisciplinary research effort that involved many independent private organizations and governmental institutions; I am grateful to all who provided meaningful input to the project. Special thanks are expressed to Messers. D. Coving-ton, A. Rodriguez, and B. Floyd of Covington Properties Inc., for their understanding, foresight and trust in carrying a project of this magnitude and scope into the implementation stage; and for the warm and cordial working conditions provided by their support staff. Dr. Rodiek, presently with the University of Arizona, was especially instrumental in presenting graphic illustrations of complex environmental plans. Mr. R. Stollar of Geraghty & Miller, Inc., provided expertise in ground water hydrology. My partner, A. Carlozzi, contributed much to editing and reviewing the manuscript.
REFERENCES Odum, E.P., 1969. The strategy of ecosystem development. Science, 164: 262-270. Phillips, E.A., 1959. Methods of Vegetation Study. Holt, Rinehart and Winston, Inc., New York, N.Y., 107 pp. Vilkitis, J.R. (Editor), 1974. Development of Regional Impact Report. Vol. 1 and 2. Covington Development Co., Land O’Lakes, Fla., 890 PP.
WILDLIFE HABITAT AS AN INTEGRAL UNIT DEVELOPMENT
171
COMPONENT OF A PLANNED
JAMES R. VILKITIS Carlo&,
Sinton,
and Vilkitis,
Inc., Amherst,
Mass. (U.S.A.)
(Received 14 December 1976)
ABSTRACT Vilkitis, J.R., 1978. Wildlife habitat as an integral component ment. Urban Ecol., 3: 171-187.
of a planned unit develop-
A planned unit development (PUD) for 8800 single family and multiple dwellings was designed and is being implemented to be consistent with the biological resources of the site and ecological parameters set by land form and function. Twenty-one disciplines within the biological, physical and social sciences were involved in the analysis and planning of the project. The guiding principle of the effort was to create an environment for people which would provide a wide range of resource uses and at the same time assure that the function of the living landscape upon which those resource uses are dependent would be maintained as an integral part of the developed community. Tbe underlying philosophy of the PUD was to enhance and maintain natural habitat for wildlife and to improve the aesthetic character of the landscape through diversifying open space, plantings and waterways. The plan attempted to create as many different and indigenous habitat types and mixes as possible within and between development areas. Upon completion of landscape renovation none of the indigenous species of wildlife known to inhabit the site were displaced due to the total destruction of their habitat. Of the four types of wildlife environments identified (forest edge, wetlands, savanna, and swamp forest), three were enhanced; the swamp forest was not altered and was set aside as a natural preserve. Forest edge was increased through the creation of adjacent non-symmetrical canals. In addition, green beltways were created along the canal system to increase the water/land habitat interface, and to serve as temporary water storage during critical storms. Wetlands and open waterbodies were renovated to create deeper water for a fishery, create additional shoreline for wildlife habitat and improve the visual quality through diversity. The uplands and improved pasture (savanna) were the areas chosen for development. Monitoring programs for the ground water and biological systems have been established and will be interpreted annually for the life of the project to determine whether the local ecology is being significantly altered. Of the 3355 acres involved, approximately 1510 acres (45%) were left as natural preserves. Plantings for landscape renovation involved only indigenous species that would not require continued maintenance.
INTRODUCTION The research
and planning
aspects
of this project
were initiated
in July
172
1973 and completed by January 1974 for the Covington Development Company (Vilkitis, 1974), managing partner of Lake Padgett Pines, to fulfill the requirements of the Application for Development Approval, Florida Law, Section 380.06, for a development of regional impact. The Master Plan which resulted from this effort is currently being implemented. Monitoring of the ground water and biological systems will continue throughout the life of the project. The Lake Padgett Pines Development is located in the west-central part of Florida (U.S.A.) in Pasco County in the town of Land O’Lakes, approximately 19 miles north of Tampa (28” 1500’N, 82” 26.25’W). The area is subtropical with a mean annual temperature of 72.3” F; the prevailing wind is from the east at a mean velocity of 8.9 mph. Annual rainfall averages 51.57 inches with the heaviest rainfall (31.03 inches) occurring from June through September. Upon completion (within 10 years), the 3355 acre development would include 8800 single family and multiple dwelling units housing 30145 residents, including approximately 7200 children of school age and 4220 persons over 60 years. It will contain recreation areas, open spaces, nature preserves, schools, and commercial facilities. All earthwork for the development was completed by January 1974; the preliminary plat for the first 151 lots was filed in November 1975. The site is contiguous with the Cypress Creek Swamp on its east border, and contains approximately 1000 acres of swamp forest. The majority of merchantable timber and source trees for turpentine production were removed prior to World War II. The uplands and pasture (savanna) have been maintained (mowed and fertilized) for cattle grazing since 1938; wetlands were excavated to provide open water for cattle. Dominant vegetation in the savanna consists of cypress heads (Z’uxodium distichum), eucalyptus (Eucalyptus spp.) and longleaf pine (Pinus palustris); there is no codominant or lesser woody species. Wildlife inhabiting the area consists of species associated with the swamp forest, forest edge, savanna, wetlands and lakes (Table I). The majority of species known to occupy the site are associated with the forest edge and wetlands. A variety of wetlands, canals and ponds (a total of 18) is scattered throughout the savanna. Prior to implementation of the planned unit development (PUD) a number of environmental issues (natural, social and political) had to be approved by state, regional and local governmental authorities. All aspects of a development with regional impacts had to be addressed and resolved in the context of the regional community. Fifteen governmental agencies were involved with the project. Twenty-one disciplines within the biological, physical and social sciences were involved in analysis and planning of the project. Our primary objective was to design and implement a PUD which would be consistent with the natural resources of the site and ecological parameters set by land form and
173
TABLE I Birds, mammals, reptiles and amphibians found on the site Birds 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
Red-headed woodpecker Yellow shafted flicker Cardinal Meadowlark Killdeer Cattle egret Bobwhite White ibis American egret Redwinged blackbird Common gallinule Water turkey Marsh hawk Great blue heron Little blue heron Mourning dove
Melanerpes ery throcephalus Colaptes auratus Richmondena cardinalis Sturnella magna Charadrius vociferus vociferus Bubulus ibis Colinus virgianus Eudocimus albus Casmerodius albus egretta Agelaius phoeniceus Gallinula chloropus cachinnans Anhinga anhinga Circus cyaneus Ardea herodias Florida caerulea Zenaidura macroura
Mammals 1. Nutria 2. Armadillo 3. Marsh rabbit 4. Fox squirrel 5. Eastern cottontail
Myocastor coypus Dasypus novemcinctus Sylvilagus palustris Sciurus niger Syloilagus floridanus
Reptiles 1. American alligator 2. Florida mud turtle 3. Striped mud turtle 4. Stinkpot 5. Florida water snake 6. South Florida swamp snake 7. Eastern garter snake 8. Florida cottonmouth
Alligator mississipiensis Kinosternon subrubrum steindachneri Kinosternon bauri palmarum Sternothaerus odoratus Natrix fasciata pictiventris Seminatrix pygaea cyclas Thamnophis sirtalis sirtalis Agkistrodon piscivorus conanti
Amphibians 1. Greater siren 2. Bullfrog 3. Peninsula newt 4. Florida cricket frog 5. Florida chorus frog
Siren lacertina Rana catesbeiana Notophthalmus viridescens piaropicola Acris gryllus dorsalis Pseudacris nigrita verrucosa
function and which at the same time would conform to all environmental, social and political legislative constraints. We recognized that it was necessary to alter the area from its prior physical form and biological character in order to accommodate any significant human activities. The problems were those of transforming physical and biological alterations to the land- and waterscape into new opportunities for
habitat. We wanted to create an environment which would provide a wide range of resource uses for man and at the same time assure that the functions of the living landscape upon which those resource uses depend were maintained. The Master Plan was designed so that all parts of the community would benefit from the physical presence of preserves, green open space and water bodies. Once the Master Plan was implemented, dwellings and their support facilities could arise in full recognition of the dual necessity to provide for man that which man must make and to provide for the continuance of a sound ecological base for that which nature must provide. We believe that this development will satisfy the physical and social needs of its inhabitants, as well as provide for the maintenance of biological life support systems which give all of us our required resources and rich diversity of aesthetic experience. Only the major biological and physical attributes of the interdisciplinary resource analysis that dealt with the wildlife-habitat-man interaction are presented here. The conceptual design for project implementation was site development planned in a fashion that would maintain and protect the existing ecosystem. The plan integrated wildlife and landscape management criteria within the restrictions set by governmental agencies, existing land use and biological and physical parameters of the site. The intent was to optimize favorable contacts between wildlife and urban residents by providing a continuum of natural habitats (waterways, green beltways, etc.) that would insure diversity of both plants and animals. The diversity within the continuum (i.e., land and water interfaces) would insure visual and habitat quality. The criteria used to develop and implement the plans were as follows: -- Habitat is a complex matrix involving the interaction of plants, animals, man, and physical factors; alterations involve a simultaneous interaction of the parts. ~ Potential land usage can be interpreted from the biological and physical attributes of the landscape; only those that offer the highest potential for alternative resource use would be considered for development. - In general, the more stable biological systems exhibit greater diversity of plant and animal species; restoration will insure maximum habitat diversity. -- Trophic levels are interconnected within biological communities, the base of which is natural vegetation. Therefore indigenous vegetation would be used for planting disturbed areas to maintain natural stability within the biological community. --- Wildlife populations are renewable resources that perpetuate themselves indefinitely if their habitat contains the necessities for completion of a life cycle. - Wildlife habitat for resident species is a function of food, water, escape cover, and reproductive areas in close proximity to each other. - Variety and interspersion of different vegetation types determine
C.rloz*l,
Fig.1.
-
Major land categories
s,n,an
A
“llkltl.
of the local and regional
1°C..
Anlher*f.
--.lL-l M*
landscape.
wildlife abundance; maximum variety and interspersion are essential to habitat restoration and enhancement. Wildlife management strategies are site specific; they must be suited to particular landscape(s) and wildlife population(s). Only indigenous wildlife
176
:LORlDlAN
AOUIFEA
iattesian
V
Fig.2. Landscape continuum.
species known to inhabit the site would be considered. Natural invasion of species not known to occupy the site might occur, but would not be sought. - The extent of landscape alteration and rehabilitation determines the visual quality of the site and the kinds and densities of wildlife present. All altered landscape would be restored to maximum species diversity and stability of the natural system. PROCEDURES
The evaluation process proceded from a general assessment of the region to an in-depth analysis of the development site. Through aerial photographic interpretation and field reconnaissance, land categories of the local and regional landscape were identified and mapped. The major categories were upland vegetation (forest), open land, pasture, open water, wetlands, swamp forest and citrus grove. Those found on the property are presented in Fig.1.
177
A profile of the landscape continuum aided in determining the interrelationship and importance of the land uses within the region to physical factors (Fig.2). The continuum provided the basis for formulating an experimental research design to assess the important physical and biological attributes of the land categories of the development site. The following attributes were analyzed. (A) Vegetation. - Proportional random sampling of forest associations for the dominant (above 6” dbh*), codominant (between 1” and 6” dbh) and lesser (below 1” dbh) woody species was undertaken to determine (1) species composition; (2) relative density (maximum total 100); (3) relative frequency (maximum total 100); (4) relative dominance (maximum total 100); (5) importance value: sum of quantities 2,3, and 4 above (Phillips, 1959); (6) growth rates of major dominant woody species determined by multiple linear regression techniques. (B) Soils. - Stratified random sampling of soil profiles for physical and chemical characteristic to determine (1) texture; (2) organic content; (3) calcium, sodium, phosphorus, and potassium concentration; (4) hydrogen ion activity (pH); (5) erosion potential (wind and water). (C) Wildlife. - Delineating potential wildlife habitats based on (1) land use history and existing vegetation; (2) major resident and transient wildlife species known to inhabit the area; (3) threatened species unique to the development site and region; (4) vegetation diversity. (D) Open water. - Stratified random sampling to determine (1) general morphology of water bodies and depth of organic sediment; (2) turbidity (materials in solution and suspension); (3) productivity (turbidity and algae); (4) major fin fish; (5) minimum and maximum temperature (bottom and top); (6) dissolved oxygen (bottom and top); (7) hydrogen ion activity (pH); (8) total phosphates (meta and ortho). (E) Ground water. - Assessment to determine (1) geologic formations; (2) principal aquifers and confining layers; (3) ground water movement; (4) best source of potable water; ____ *dbh refers to the diameter
of a tree at breast height (4.5
ft.).
178 (5) potential yield of aquifers containing potable water; (6) water quality; (7) impact of ground water diversion of 3.5 million gallons per day (mgd) from major aquifer on surface water bodies and water table; (8) potential of salty water encroachment. (F) Land use. - To determine (1) history of land use; (2) potential utilization. The baseline data (including that which dealt with the social and cultural sciences) after analysis was integrated into a landscape management plan for the PUD through an interdisciplinary impact assessment process. At this stage the pros and cons of development on specific sites were weighted as to their potential impact on the physical and biological features of the landscape. Through this integrated assessment, sites were evaluated qualitatively and quantitatively in terms of their ability to sustain development, and subsequently were categorized in terms of their potential uses. Our “functional landscapes classification” system was patterned after Odum (1969) and included production, protection, compromise and urban-commercial environments. The components represent, in general, the spectrum of ecological conditions found anywhere. Productive environments are growth systems characterized by rapid turnover of resources, short life cycles, high production rate and relatively simple life forms; these systems cannot be subject to long or varied stresses. Protection environments are characterized by a slow turnover of nutrients, rather long life cycles, and large and more diverse life forms; they can tolerate considerable stress without total collapse. According to Odum, compromise environments are mixed systems of protection and production environment. The compromise environment on the site consisted of upland pine forest and improved pasture; there were no protection environments included in our classification. Urban-commercial environments which are ecologically non-vital areas created by man did not exist on the landscape prior to development. In general, the natural and physical features of the functional landscapes set the basic parameters by which development planning proceeded; that is, the exact juxtaposition of housing units, structures, roadways, etc., in the natural environment. The functional landscapes identified on the site are presented in Fig.1. RESULTS
The water table altitude controls the major biological and physical attributes of the site and related local ecology. It receives recharge from precipitation and runoff and the discharge of the Floridan aquifer under artesian conditions. The altitude of the water table controls (1) diversity and productl vity of flora and fauna in the swamp forest and wetlands; (2) water levels in existing canals and lakes; and (3) the growth rate of dominant indigenous vegetation in the pasture and upland areas (Fig.2).
179
The PUD upon completion would require on-site removal of 3.15 mgd of potable water from the Floridan aquifer and would cause the water table in the shallow aquifer around the well field to drop one or two feet. To further complicate the ground water situation, an independent municipal plan (unapproved by state or regional water control planning agencies) to withdraw an additional 55 mgd from an adjacent site is being undertaken. This plan, when completed, will cause severe local drawdown, critically altering existing shallow ground water levels and destroying the existing biological character of the communities that inhabit the area and region. Prior to any development, surface runoff discharged naturally through the northeast and southeast corners of the property into the swamp forest as fast as the drainage basin would allow (Fig.1). There appeared to be no alteration of the biological communities from this discharge. However, upon project completion there would be a substantial increase in surface runoff due to roads, structures, parking lots, etc. The engineers estimate that a 25-year storm would generate a peak flow of approximately 700 cubic feet per second (cfs) which would discharge into Cypress Creek Swamp quickly without flood control. This volume of water would disrupt the local biological, physical, and cultural resources and add to regional flood conditions from streams draining the eastern and southern portion of the swamp. Existing water bodies (90 acres) consisted of ponds, canals, and intermittent wetlands. In general the ponds and canals were shallow, relatively unproductive bodies (based on secchi disc, phosphates, and pH indicators) with few fin fish. There was low primary production and little nutrient circulation. Wetlands with less than 3 feet of water were weed choked due to eutrophication caused by grazing cattle; those with more than 3 feet of water, which inhibited grazing, had no bottom vegetation. The pH (average 5.8) was well below the range (6.6 to 9.0) that produces the best growth rates and reproductive success of the indigenous fin fish. The temperature (top and bottom), dissolved oxygen, and total color (suspended and dissolved materials) were suitable for supporting high fish populations. Shoreline vegetation was sparse or nonexistent, since the pasture and open areas of the upland forest were mowed to the water’s edge to maintain grasses and improve access for stock. Low primary productivity was attributed to the morphology of the water bodies, and to low pH and lack of available nutrients in the water and adjacent land. The fine, sandy (above 65% by volume) soils allowed lateral movement of shallow ground water to the canals and lakes. The soils were acid (pH 5.2 to 5.7) with low natural fertility (lack of weathering) and low moisture-holding capacity. The low water-holding capacity of the soils poses a problem to terrestrial plants when the shallow ground water level is lowered below their effective rooting zone. The 3.15 mgd on-site withdrawal would cause the surface ground water level to drop to below this zone only within several hundred feet of a pumping well; the off-site withdrawal of 55 mgd has potential to lower the surface water level below this zone over the entire property.
180
The soil productivity of the site, reflected by nutrient capabilities within a forest classification was, in general poor to fair. They were, however, classified in order of their relative productivity within the site. The area with the best soil for growing vegetation was the ecotone between the wet and upland areas; the swamp forest and upland forest soil was good to fair, and the open land and pasture was the poorest. Three functional landscapes were identified on the site, and were defined as follows: .- Production environments include fresh permanent water at least 3 feet deep, and wetlands with permanent or intermittent water less than 3 feet deep. -- Protection environments include cypress heads in the pasture, swamp forest that experiences periodic flooding, and the hardwood-cypress forest ecotone between the pasture and swamp interface. -- Compromise environments include the open pasture, pine stands in the upland areas, and the hardwood stands in the open pasture. IMPLEMENTATION
Based on the preceeding assessments, three major development decisions were made. First, in order to maintain and perpetuate the delicate balance between the ground water and biological systems, water would have to be added and maintained on the site to compensate for ground water withdrawal. Second, development areas would include only the upland area and pasture (compromise environment), since they had the least biological diversity, and had been continuously altered by man in the past and could sustain the greatest amount of disturbance with the least detrimental effect on the total environment. Third, the swamp forest (protection environment), due to its unique biologic character in the site and region, was excluded from development. To maintain the balance between the ground water and biological systems, water would be added and retained on the site for maximum ground water recharge. The additional water would come from runoff and tertiary treated effluent (2.4 mgd). It would be detained on the site in lakes and through a system of interconnecting canals. The canal system would serve to: -- return and retain (through a system of weirs) the water that has been used from the Floridan aquifer in order to allow adequate time for it to percolate through the soil and recharge the shallow aquifer; -- maintain the water table altitude at its normal level; quickly drain water generated from critical storms off the landscape; -- direct storm water to natural long-time drainage areas so as to prevent erosion and water damage; -- allow maximum water retention time, through controlled outflow so that the water would purge itself through natural processes of detergents, solvents, and other chemical agents that are not immediately biodegradable;
181
Housing
+ Indigenous
Plantings
.stabilize
canal
.enhance
wildlife
.discourage .native
plants
on
1 T3
Slope
bank habltat
access require
to
water less
maintenance
Fig.3. The canals and green beltways are located next to the existing forest edge and serve as flood control devices. They were designed to serve as green beltways and as separators for the forest edge. Periodic weir dams will allow for fisheries management. Where length permits, flat-bottom boats can be used for water-based recreation.
- create new and diverse habitats for aquatic and shoreline wildlife species,
and provide recreation and nature study opportunities; --- act as a buffer area by limiting access to the contiguous swamp forest. The lakes would function as: --~-storage areas for water generated from storms and runoff; - polishing lagoons for temporary storage of storm and tertiary effluent; - a fishery providing additional shoreline and water habitat for wildlife; - additional surface water for recreation. Approximately 3 million cubic yards of earth were excavated to create 350 acres and improve 90 acres of open water; a total of 440 acres. The earth was taken from areas adjacent to the forest, around ponds, and along natural and man-made drainage areas. The land disturbed involved approximately 410 acres of pasture, 28 acres of wetland, and 2 acres of forest. All earth removed was used to fill low lying areas in the uplands and pasture that flooded temporarily during heavy rains. The canals and adjacent green beltways were designed with a series of weirs to control water levels at the 25 year flood level (1345 acre feet) for slow discharge into the swamp forest. Under natural conditions a 25year storm would have a peak flow discharge of 700 cfs; this would be reduced to 75 cfs through the canal and weir system. Bottom discharge provided maximum nutrient circulation for use by
Fig.4. The swamp forests in the eastern areas of the property are fragile and easily upset by heavy development. The canals will buffer them from the impact of the residents by limiting access, while at the same time allowing residents to live in close proximity.
the biological systems. The water levels in the canals would correspond to that which would be expected under natural local climatic conditions. Emergency popoffs were designed for storms greater than the 25-year flood. Initially the site served as a discharge area for ground water in the surficial aquifer. The new canals and lakes coupled with ground water removal would initially cause a drop in the water table; however the water added to the canal system would increase its head and eliminate any discharge from shallow water table formation into the canals and lakes. A green beltway with a 1 : 3 slope, 25 to 30 feet in width, adjacent to the canals but lower than upland development would serve as temporary storage for excessive runoff for ground water recharge and later release (Fig.3). The canal system would also assure, by limiting access, that the swamp forest would not be disturbed (Fig.4). This isolation would provide opportunity for the wildlife species associated with the swamp community to perpetuate themselves. Plantings of 60,000 indigenous shade trees were initiated during 1973 along the forest edge and periphery of the green beltway to stabilize canal and pond banks while enhancing wildlife habitat. Species chosen were those that would meet existing environmental conditions, rather than those that would require alteration of the environment to meet species requirements. Plantings were strategically placed to discourage indiscriminate human access to the canal (Fig.3), to maintain a natural outdoor-type experience for those recreating on the water, to protect wildlife habitats, and to limit recreational use of the canal system.
Waterbodies and wetlands were altered to increase shoreline and vegetation diversity to enhance the potential for wildlife use and fish production. Shallow wetlands with a deep organic sediment were not altered. Those near open water with a sandy substrate were deepened and/or widened (Fig.5). Shorelines were non-symmetrical to increase edge. A gentle slope was created near the shore for both waterbodies and wetlands and planted with indigenous species of plants to control access and improve habitat. Once the development is completed, walkways would be constructed near and/or over them; their location would be such that there would be minimal disturbance to the vegetation and wildlife (Fig.6). The canals and open water were designed to serve not only as havens for wildlife and water detention areas but also as a fishery (Fig.7). To mitigate the problems associated with the low aquatic productivity (pH and water depth) and the turbidity caused by the creation of the canals and deepening PLAN -“New
Option
SECTION ” ,ew
1 higher
Option
Fig.5.
fish
production
2
Alterations
in waterbodies
and wetlands.
Fig.6. Proposed treatment for existing wetlands includes clearing and deepening some areas near open water. Reducing steep profiles near banks to improve shore bird habitat, and constructing a walkway and overlook system in some of the more likely developed wetlands for outdoor recreation and education experience.
Green seltway
Wew Dam lbttom
Fig.7. lation
The management of weir dams.
Swamp
on Canal
Forest
Release
of canals for use as a fishery
becomes
prossible
through
the instal
of the waterbodies, the following procedures were implemented: - Prior to water and wetland improvements, the upland area was treated with 50 pounds of hydrated lime per acre. The plan was to slowly increase the pH of the water bodies through leaching to approximately 7.0 without causing sudden stress to the existing aquatic biota. The higher pH would allow the density of microscopic plants and organisms to increase without directly fertilizing the waterbodies. Fertilization was not recommended due to the continued maintenance required. The circulation of existing nutrients was increased by requiring all weirs to have bottom releases. This allows nutrients coming into the system from the landscape to be continuously circulated. .-- To inhibit the growth of undesired submerged aquatic vegetation, a problem which is characteristic of subtropic waters, the depth of the canals
185
Development
Housing Commercial
II
Recreation
=
Circulstwn
=
Natural Preserves Forest. Open
Wetland Water
Natural
Canals
Drainatte to Swamp & Greenbelt
a
Ez3 A
m
LAKE Land
0’
PADGETT
PINES.
Lakes.
Florida
Carloxzi* Fig.8. Master Plan for the site.
Sinton
A Vitkitis
MASTER
Dec.
PLAN
10. 1973
U.S.A. Inc..
Amherst.
Ma
USA
186
and ponds was increased to between 5 and 8 feet (Fig.5). The effective light penetration for the waterbodies measured with a Secchi disc was approximately three feet. By maintaining a depth greater than 3 feet, problems of managing submerged aquatic vegetation were lessened. -- Water turbidity caused by construction was eliminated by the application of approximately 500 pounds of gypsum per acre of water surface to flocculate suspended sediments. Gypsum is chemically neutral and can be applied immediately after dredging at any time of the year. Once the proper depth was obtained and the turbidity eliminated, stocking of mature 1 year old bass (Micropterus salmoides) at two fish per acre was recommended. Thereafter, the fishing management strategy to maintain a well structured population was to remove all fish caught, large and small since returning small fish disturbs the population balance. Wire waste fish baskets on swing poles adjacent to the swamp side of the canal would be provided for disposal of unwanted fish. The baskets would be designed to allow all scavengers easy access to recycle biomass. The Master Plan for the site illustrating all the development strategies is presented in Fig.3 To assure that the delicate balance between the shallow ground water and biological systems is maintained, a continuous monitoring program was established. Shallow ground water observation wells located in key areas on the site were equipped with continuous ground water recording devices. Trends in ground water levels are evaluated quarterly. In addition, it was observed that certain dominant upland vegetation had their lower root systems at the water table. It was established over a 15-year period that the growth rate (radial increment) was a function of ground water level fluctuations. Over 50 trees throughout the site that exhibited radial growth increment with ground water fluctuations were fitted with dendrometer bands. Results of their increment are assessed annually to determine if their growth falls within established confidence limits. ACKNOWLEDGEMENTS
The Master Plan for the Lake Padgett Pines Development was the result of a comprehensive interdisciplinary research effort that involved many independent private organizations and governmental institutions; I am grateful to all who provided meaningful input to the project. Special thanks are expressed to Messers. D. Coving-ton, A. Rodriguez, and B. Floyd of Covington Properties Inc., for their understanding, foresight and trust in carrying a project of this magnitude and scope into the implementation stage; and for the warm and cordial working conditions provided by their support staff. Dr. Rodiek, presently with the University of Arizona, was especially instrumental in presenting graphic illustrations of complex environmental plans. Mr. R. Stollar of Geraghty & Miller, Inc., provided expertise in ground water hydrology. My partner, A. Carlozzi, contributed much to editing and reviewing the manuscript.
REFERENCES Odum, E.P., 1969. The strategy of ecosystem development. Science, 164: 262-270. Phillips, E.A., 1959. Methods of Vegetation Study. Holt, Rinehart and Winston, Inc., New York, N.Y., 107 pp. Vilkitis, J.R. (Editor), 1974. Development of Regional Impact Report. Vol. 1 and 2. Covington Development Co., Land O’Lakes, Fla., 890 PP.