Restoration of a south Florida forested wetland

ECOLOGICAL ENGINEERING ELSEVIER

Ecological Engineering 5 (1995) 143-151

Short Communication Restoration of a south Florida forested wetland Jeffrey D. Weller * Broward County Parks and Recreation Division, Fern Forest Nature Center, 201 Lyons Road South, Pompano Beach, FL 33068, USA

Accepted 21 January 1994

Abstract

A rewatering project conducted at Fern Forest Nature Center in Pompano Beach, Florida, USA, has rejuvenated and restored an area of south Florida forested wetland to its pre-drainage condition in three years. Through the removal of undesirable vegetation such as Brazilian pepper (Schinus terebinthifolius) and the re-introduction of water, the following have been accomplished: increase in surfacewater duration time; elevation of groundwater by 70 to 84 cm; rejuvenation of a depressed forested wetland, a deciduous hardwood swamp, and an emergent wetland; and enhancement of a wading bird habitat, a cypress dome, and 3.2 km of shallow stream bed (1.5 m deep or less). These accomplishments have assured the survival of the park's 34 rare and endangered fern species and encouraged the natural return of 16 wetland bird species, 8 fish species, 6 species of turtles, 6 species of snakes, 5 snails, 2 frog species, and even the American alligator (Alligator mississippiensis). Keywords: Cypress/maple swamp; Groundwater recharge; Rewatering project; South Florida

1. Introduction

Eighty-one percent of the terrain that originally supported bottomland forests in the United States has been converted to other land uses (Clewell and Lea, 1990). Presently, many projects are underway throughout the southeastern United States to restore these areas. Most restoration specialists claim these projects will require decades of research to thoroughly assess ecosystem functions before declaring them successful. This time period is unsatisfactory for project coordinators who are anxious to gain release from regulatory obligations within 3-5 years. * Corresponding author. Present address: 5124 McKinley St., Hollywood, FL 33021, USA. 0925-8574/95/$09.50 © 1995 Elsevier Science B.V. All rights reserved SSDI 0925-8574(94)00042-4

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This project demonstrates that when certain hydrological criteria are met and vegetational composition and animal resurgence documented, restoration of valuable ecosystem functions can be inferred and may be grounds for declaring a project successful in as short a time as 5 years. This paper focuses on vegetational composition and animal resurgence and touches lightly on the complex task of evaluating ecosystem functions.

2. Methods

2.1. Site description Fern Forest Nature Center, a member of the Broward County Parks and Recreation Division, is a 102-ha designated urban wilderness park in the Fort Lauderdale area, Florida, USA. This site is rich in botanical diversity as well as south Florida biological history. Historically, Lake Okeechobee overflowed seasonally and sent water southward through the Everglades. Some of this water discharged southeastward to the ocean through depressions in the Atlantic Coastal Ridge. Fern Forest lies in one of these depressions, designated as Cypress Creek Slough (Pierce, 1970). Cypress (Taxodium) and maple (Acer) flourished here and helped create the organic muck soil in Fern Forest (Soil Survey of Broward County, 1976). Unfortunately, this area was drained in the early 1900s through the construction of water management canals for flood abatement, agriculture uses, and development. Botanically, the park contains 11 ecosystems including a pineland, a sub-tropical hardwood hammock, and an oak/cabbage palm community. The site contains a population of 34 species of rare and endangered ferns and an unusual geological formation of exposed marl limestone. This limestone draws groundwater to the surface through capillary action, causing an increase in hammock humidity. Several wetlands, identified when the park was surveyed in the late 1970s, conformed to the wetland types defined by Cowardin et al. (1979) and Mitsch and Gosselink (1986). During that assessment of the park, plant and animal surveys were conducted, and remnants of the historical slough were discovered, including several small isolated wetlands, a deciduous hardwood swamp, a cypress swamp, and large amounts of desiccated marl limestone (MacAdam, 1992). These areas comprised 26 ha or approximately 25% of the park and no longer functioned as wetlands, but were succeeding to undesirable vegetation, namely Brazilian pepper ( Schinus terebinthifolius ). 2.2. Restoration approach In 1988 a proposal was submitted to Florida's Department of Environmental Regulation to acquire the funds needed to restore this park to its pre-drainage condition. The cooperative agencies were Florida's Department of Environmental

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Regulation, the Broward County Parks and Recreation Division, and the Broward County Office of Environmental Services. The objectives of this project were to enhance the few remaining wetland areas, re-hydrate the drained wetlands, promote the re-colonization of native wetland plants, and re-establish several vital wetland functions, specifically: 1. wildlife habitat; 2. fishery habitat; 3. water storage which contributes to stream flow during the dry season; 4. maintenance of ecosystem functions through biotic diversity, food chain support, and water filtering and water quality; and 5. groundwater recharge (Clewell and Lea, 1990). The rewatering of the park was to be accomplished by utilizing the adjacent Cypress Creek canal, a South Florida Water Management District flood abatement canal, as a water source. Water from the canal was pumped into the park and allowed to flow throughout the site by utilizing the naturally occurring lower elevations. Stop log risers of varying diameters were installed to direct and regulate the water flow throughout the park. These risers utilized 5 cm x 15 cm flash boards to regulate the water flow through the adjoining culvert. A single 3.0 x 104 l/min pump was installed to add water to the park. Twelve surfacewater gauges were set up to monitor the water which entered the park through the pumping system and two U.S. Geological Survey groundwater wells were installed to monitor recharge. The boundaries of all wetland areas were delineated by botanical identification, soil samples, and the method described in Field Guide for Wetland Delineation (WTI, 1989). A plant survey of low-lying isolated wetland areas was conducted prior to the introduction of any water into the park (Table 1). All the plants were classified as true wetland plants, as referenced through Hotchkiss (1972), Dressier et al. (1987), and Elias (1989). To improve the probability of project success, the following procedures were adhered to: 1. The addition of pumped water was only to occur in natural amounts. Currently, canals and retention ponds scattered throughout the county impede the natural southeastern flow of water and capture runoff that would otherwise reach the park. Pumping compensated for this water loss. 2. The amount of water pumped would follow the south Florida wet and dry seasons. The wet season is from May through September. 3. The introduced water was contained entirely within the delineated wetland areas. 4. Pumping was interrupted when rain was forecast, so that natural precipitation could hydrate the system. Canal water was tested every other day to assure suitable water quality. Herbicides, which are sometimes applied to the aquatic weeds in the canal by the South Florida Water Management District, were of specific concern. Fertilizer runoff from neighboring farms carried in the canal water was a potential source of eutrophication within the park. In two years of water testing, the water quality test results never exceeded dangerous limits.

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3. R e s u l t s

3.1. Hydroperiod

Prior to the first week of operation, July 10, 1990, the duration for 5 cm of surfacewater in the low-lying areas of the park was only 48 h. Presently the surfacewater duration for those same areas increased to 144 h. The two U.S. Geological Survey deep wells have shown a substantial recharge to the groundwater (Fig. 1). While scattered underlying clay soils made percolation nearly impossible in some areas of the park (Larson, 1982), the capillary fringes of the internal isolated wetland sites were permeable (Heimberg, 1984) and increased the elevation of two groundwater monitoring wells by 70 cm and 84 cm. Owing to elevated ground water levels, the exposed marl limestone is again drawing water to the surface and increasing the overall hammock humidity. This process is important for the survival of the limestone as well as the park's fern and bromeliad population. 3.2. Vegetation

Of all the naturally occurring on-site cypress (Taxodium) trees surveyed prior to the addition of water, only 22 were found to be under the age of 25 years old and no seedlings were discovered. In 1993, surveys found 35 cypress tree seedlings measuring up to 1 m in height, evidence that rejuvenation of a depressed cypress forest is in progress.

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J.D. Weller / Ecological Engineering 4 (1995) 143-151 Table 1 Wetland-associated plants at Fern Forest Nature Center Documented sighting after re-hydration Trees Red maple Pond apple Dahoon holly Red bay Laurel oak Water oak Cabbage Palm Willow Bald cypress

Acer rubrum var. tridens Annona glabra Ilex cassine Persea borbonia Quercus laurifolia Quercus nigra Sable palmetto Salix caroliniana Taxodium distichum

Shrubs Salt bush Buttonbush Cocoplum Water-primrose Wax myrtle Elderberry

Baccharis halimifolia Cephalanthus occidentalis Chrysobalanus icaco Ludwigia octovalvis Myrica cerifera Sambucus simponii

Herbs, ferns and algae Leather fern Alligator weed Toothcup Climbing aster Marsh aster Azolla fern Water hyssop Bog-hemp Coin wort Algae Wild taro Swamp lily Buttonweed Eclipta Water hyacinth Hydrilla Penny wort Red ludwigia Hemp Naiad Spatterdock Royal fern Arrow arum Water lettuce Algae Marsh fleabane Giant pluchea Rust weed Pickerel weed Duck potato

Acrostichum danaeifolium Althernanthera philoxeroides Ammannia latifolia Aster carolinianus Aster subulatus Azolla caroliniana Bacopa monnieri Boehmeria cylindrica Centella asiatica Chara sp. Colocasia esculentum Crinum americanum Diodia •irginiana Eclipta alba Eichhornia crassipes Hydrilla verticillata Hydrocotyle umbellata Ludwigia repens Mikania scandens Najas guadalupensis Nuphar luteum Osmunda regalis vat. spectabilis Peltandra virginica Pistia stratiotes Pithophora sp. Pluchea camphorata Pluchia symphytifolia Polypremum procumbens Pontederia lanceolata Sagittaria lancifolia

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Table 1 (continued) Documented sighting after re-hydration Arrowhead Water spangles Lizard tail Fox tail Goldenrod Smut grass Alligator flag Cattail Bladderwort

Sagittaria latifolia Salvinia minima Saururus cernuus Seteria geniculata Solidago sempervirens Sporabolus jaquemontii Thalia geniculata Typha angustifolia Utricularia gibba

Grasses, sedges and rushes Broomsedge Carpet grass Para grass Sedge Sawgrass Sedge Sedge Flat sedge Sedge Umbrella sedge Sedge Sedge White-topped sedge Wild millet Goose grass Fringe rush Rush Rush Southern cut grass Silk reed Fall panicum Maidencane Guinea grass Torpedo grass Red topped panicum Knot grass Water paspalum Vasey grass Napier grass Giant reed

Andropogon glorneratus Axonopus furcatus Brachiaria mutica Carex alata Cladium jamaicense Cyperus brevifolius Cyperus glabulosus Cyperus haspan Cyperus ligulads Cyperus odoratus Cyperus polystachyos Cyperus surinamensis Dichromena latifolia Echinochloa waited Eleusine indica Fimbristylis cymosa Juncus marginatus Juncus virbinum Leersia hexandra Neyraudia reynaudiana Panicum dichotomiflorum Panicum hemitomon Panicurn maximum Panicum repens Panicum dgidulum Paspalum distichum Paspalum repens Paspalum urvillei Pennisetum purpureum Phragmites communis

x x x x x x x

x x x x x x x x x x x x × x x x x x x × x x x x x

Thirty-seven new plant species have been documented in the park's low areas since the addition of water (Table 1).

3.3. Wildlife The sightings of 16 aquatic birds, 21 aquatic animal species and 8 fish species (Ashton and Asthon, 1981a,b; Cunningham-Pascatore, 1993), all reproducing resi-

J.D. Weller /Ecological Engineering 4 (1995) 143-151 Table 2 Animal species sighted in fern forest which were absent prior to hydration Birds Spotted sandpiper Anhinga Limpkin Great blue heron Cattle egret Green-backed heron Great egret Killdeer Snowy egret Tricolor heron White ibis Little blue heron Wood stork Black-crowned night heron Osprey Purple gallinule

Actitis macularia Anhinga anhinga Aramus guarauna Ardea herodias Bubulcus ibis Butorides striatus Casmerodius albus Charadrius vociferus Egretta thula Egretta tricolor Eudocimus albus Florida caerulea Mycteria americana Nycticorax nyticorax Pandion haliaetus Porphyrula martinica

Reptiles and Amphibians Alligator Giant toad Snapping turtle Peninsula cooter Redbelly turtle Yellowbelly slider Southern black racer Eastern Indigo snake Green treefrog Florida mud turtle Florida Kingsnake Scarlet Kingsnake Florida water snake Brown water snake Cuban treefrog Softshell turtle

Alligator mississippiensis Bufo marinus Chelydra serpentina Chrysemys floridana peninsularis Chrysemys nelsoni Chrysemys scripta scripta Coluber constrictor priapus Drymarchon corais couperi Hyla cinerea lOnostemon subrubrum steindachneri Lampropeltis getulus floridana Lampropeltis triangulum elapsoides Nerodia fasciata pictioentris Nerodia taxispilota Osteopilus septentrionalis Trionyx ferox

Fish Oscar Killifish mosquito fish White catfish Channel catfish Florida gar Largemouth bass Talapia

Astronotus ocellatus Fundulus diaphanus Gambusia affinis lctalurus catus lctalurus punctatus Lepisosteus platyrhynchus Micropterus salmoides Talapia sp.

Mollusks Pond snail Papersheil Wheel snail Orb snail Apple snail

Amnicola limnosa Anodonta grandis Gyraulus hirsutus Helisoma anceps Pomacea paludosa

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d e n t s ( T a b l e 2), at the site in such a short period of time, correlate directly to the a d d i t i o n of water a n d to the r e - e s t a b l i s h m e n t of several types of w e t l a n d c o m m u n i ties.

4. Discussion Articles have b e e n w r i t t e n o n forested w e t l a n d restoration, but a u t h o r s fail to call the projects successful, claiming 1 5 - 2 0 years are n e e d e d to assess certain w e t l a n d functions including: g r o u n d w a t e r recharge, flood storage, food chain support, fishery habitat, wildlife habitat, a n d heritage ( A d a m u s , 1983; Clewell a n d Lea, 1990). A t this site, all of these w e t l a n d functions have b e e n realized in only t h r e e years. If these functions can be e n h a n c e d d u r i n g the next two years, all three c o n t r i b u t i n g agencies will declare this project a f u n c t i o n i n g ecosystem after just five years of o p e r a t i o n . W i t h the increased d e v e l o p m e n t of south Florida, this m e c h a n i c a l m e t h o d of r e s t o r a t i o n could prove successful in preserving the few r e m a i n i n g u r b a n w e t l a n d s in F l o r i d a in a relatively short period of time.

References Adamus, P.R, 1983. A Method for Wetland Functional Assessment. Vol. II. The Method. U.S. Department of Transportation, Federal Highway Administration, Office of Research, Environmental Division, Washington, DC. Ashton, R.E. Jr. and P.S. Ashton, 1981a. Handbook of Reptiles and Amphibians of Florida: Part l, The Snakes. Windward Publishing, Miami, FL. Ashton, R.E. Jr. and P.S. Ashtom 1981b. Handbook of Reptiles and Amphibians of Florida: Part 2, Lizards, Turtles and Crocodilians. Windward Publishing, Miami, FL. Clewell, A.F. and R. Lea, 1990. Creation and restoration of forested wetland vegetation in the southeastern United States. In: J.A. Kusler and M.E. Kentula (Eds.), Wetland Creation and Restoration: The Status of the Science. Island Press, Washington, DC, pp. 195-231. Cowardin, L.M., V. Carter, F.G. Golet and E.T. LaRoe, 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, FWS/OBS-79/31, Washington, DC. Cunningham-Pascatore, P., 1993. Fern Forest Nature Center. 201 Lyons Road South, Pompano Beach, Florida, 33068. Personal correspondence. Dressier, R.L., D.W. Hall, K.D. Perkins and N.H. Williams, 1987. Identification Manual for Wetland Plant Species of Florida. Institute of Food and Agricultural Sciences, University of Florida, Florida. Elias, T.S., 1989. Field Guide to North American Trees. Grolier Book Clubs, Danbury, CT. Heimberg, K., 1984. Hydrology of north-central Florida cypress domes. In: K.C. Ewel and H.T. Odum (Eds.), Cypress Swamps. University Press of Florida, Gainesville, FL, pp. 72-82. Hotchkiss, N., 1972. Common Marsh, Underwater and Floating-Leaved Plants of the United States and Canada. Dover Publications, New York. Larson, J.S., 1982. Understanding the ecological values of wetlands. In: Research on Fish and Wildlife Habitat. EPA-600/8-82-002, U.S. Environmental Protection Agency, Washington, DC, pp. 108-118. MacAdam, G.0 1992. Broward County Parks and Recreation Division. 950 NW 38th Street, Oakland Park, Florida, 33309. Personal correspondence. Mitsch, W.J. and J.G. Gosselink, 1986. Wetlands. Van Nostrand Reinhold Company, New York.

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Pierce, C.W., 1970. Personal Manuscripts. In: D.W. Curl (Ed.), Pioneer Life in Southeast Florida. University of Miami Press, Florida. Soil Survey of Broward County, Florida, Eastern Part, 1976. United States Department of Agriculture, Soil Conservation Service. Sheet number 9. Wetland Training Institute, Inc., 1989. Field Guide For Delineating Wetlands: Unified Federal Method. WTI 89-1, 131 pp.