Passive establishment of vegetation in constructed wetlands in agricultural settings: a case study (1).

Luckeydoo, Lee M. ; Fausey, Norman R. ; Davis, Craig B. 等

ABSTRACT. Three wetlands constructed in 1995 on land adjacent to agricultural fields in northwest Ohio were allowed to establish vegetation passively. Survey data collected 1998-2001 from quadrats in open water, frequently and infrequently submerged zones within the basin, identified 77 species over the three sites. Greatest species diversity occurred in the infrequently and frequently submerged zones. The dominant species within the wetlands originated from agricultural fields, nearby drainage ditches, streams, and the seeded erosion control buffer zones surrounding the wetlands. Six years following construction, less than 50% of the dominant species were wetland species. Results suggest that for constructed wetlands in agricultural settings, plantings or seeding of desired species will be required to supplement the existing sources of wetland vegetation species.

INTRODUCTION

The introduction of constructed wetlands in agricultural watersheds of the Mississippi basin has been recommended to reduce non-point source nutrient contributions to the Gulf of Mexico (Mitsch and others 1999, 2001; Hey 2002). Vegetation in such wetlands is most often established by seeding or transplanting seedlings in the basin following construction, and there is much literature available on the methodology and results (Allen and others 1989; Marble 1992; Payne 1992; Thunhorst 1993; Hammer 1997). An alternative approach is to allow for species that may passively establish from the seed bank or be recruited from outside the wetland. Wetland management for passive establishment selects for species to establish from the seed bank or from outside the wetland (Welling and others 1988; Collins and Wein 1995). Risks of passive vegetation establishment are that seed bank richness may be insufficient or that the surrounding areas may provide both suitable and undesired or invasive species (Weinhold and van der Valk 1989; Galatowitsch and van der Valk 1995).

The objective of this work was to examine how constructed wetlands built on converted cropland passively develop vegetation. Specifically, this study was conducted to document the rate and type of passive vegetation establishment in Wetland Reservoir Subirrigation Systems (WRSIS) project sites and, thereby, aid in the decision to use passive revegetation in future project sites.

SITE DESCRIPTION AND METHODS

This time limited study examined and identified the vegetation that established in three constructed wetlands located in the Maumee River watershed in Defiance, Fulton, and Van Wert counties in northwest Ohio. Each location had been under row crops or sod for at least 20 years prior to construction, which occurred in 1995. The size of the constructed wetland was 0.12 ha in Defiance County, 0.57 ha in Fulton County, and 0.79 ha in Van Weft County. The average water depth in the wetland was >30 cm, but features such as shelves, earthen dividers, and gentle bank slopes (6-10:1) were designed into the basins to promote vegetation establishment. Vegetation was allowed to establish passively, with the exception of erosion control seeding along the buffers of the basin. The buffers of the three sites received similar species in the erosion control applications, that is, Medicago sativa L., Phleum pratense L., Ecbinochloa crusgalli (L.) P. Beauv., Festuca pratensis Hudson., Dactylis glomerata L., and Trifolium repens L. The Fulton and Van Wert locations also received Bromus spp. The wetlands received subsurface drainage and runoff waters from adjacent agricultural fields under corn (Zea mays L.), soybean (Glycine max L.) rotation cropping systems. The annual water level of the constructed wetlands varied 15-25 cm during the study.

Field surveys were conducted to determine plant species, number of individuals and zonation of growth by randomly placing four 1.0 [m.sup.2] quadrats in each of (a) the frequently submerged zone (W) extending 0.5 m above and below the average water level, (b) the infrequently submerged zone (I) 1.0 m above zone W, and (c) the open water zone (O) under standing water. Data were collected using a stratified random sampling technique (Luckeydoo 2002; Luckeydoo and others 2002). The Braun-Blanquet (1932) method which included percent cover, species composition, grouping, and age was used to collect qualitative information about plant species and calculate Importance Factor (IF) rankings (Cox 1996). Species were considered dominant (top 10 of the ranked IF species) if they occurred for more than 50% of the individual seasons. Nomenclature follows Gleason and Cronquist (1991) and Fassett (1969).

RESULTS AND DISCUSSION

Species richness was 43 at Fulton, 50 at Van Wert, and 53 at Defiance over 4 years of study. A total of 77 species were identified in the three constructed wetlands during 1998-2001 (Table 1); the infrequently submerged zone (68 species) and the frequently submerged zone (59 species) contained more species than the continually submerged open water zone (9 species).

Wetland indicator species made up 45% (35 species) of the total species present (Table 1), most of which were facultatively (Reed 1988; USFW 1996) associated with wetland conditions. The proportion native to North America varied from 71% (Fulton) to 85% (Van Wert) to 86% (Defiance).

Importance Factor (IF) values (Table 2) suggested that local sources were most likely responsible for supplying the species which established. Highly ranked wetland and hydrophytic IF species such as Salix exigua Nutt., Echinochloa crusgalli (L.) P. Beauv., Scirpus atrovirens Willd., Phalaris arundinacea L., Polygonum persicaria L., and Carex vulpinoidea Michx. were noted to grow along the field edges, in nearby surface drainage ditches, and along entrance roadways. Many of the IF species have been reported to serve as sources of food, cover, and nesting locations for wildlife (McAtee 1939; Payne 1992), and seeds may have been delivered by visiting wildlife, waterfowl, or by wind or water movement. Non-wetland species such as Phleum pratense L., Medicago sativa L., Dactylis glomerata L., Bromus sp., and Festuca pratensis L. that had been planted on the buffer zones after construction as erosion control, likely served as a seed source for the infrequently and frequently submerged zones.

Wetland indicator species did not account for more than 50% of the dominant species, 6 years following construction, at any of the three locations. These results indicate that, despite basin design characteristics installed to promote wetland vegetation establishment, passive vegetation alone may not be able to establish more than 50% dominant wetland indicator species on similar constructed sites. The results of this study suggest that planting or seeding basins with desired species, in areas such as agricultural settings where limited wetland species propagule supply exists, will be required if 50% or greater wetland vegetation is desired within 6 years of construction.

An idea to increase the potential for wetland species establishment arises from the presence of erosion control plantings in the list of dominant IF species in the studied wetlands. Seed of wetland native species could be added into erosion control mixtures applied to the buffer in order to further promote wetland vegetation establishment and diversity. Species suggestions for Ohio include: Elymus virginicus L. (Wild rye), Juncus effusus L. (Soft rush), Andropogon gerardii Vitman. (Big Bluestem), and Panicum virgatum L. (Switchgrass, caution: some varieties aggressive). These species are only a few of the possible appropriate species, but are offered because they are all perennial wetland species (FAC and FACW) native to Ohio (Sheaffer and Rose 1998), are easily obtainable through seed companies, and are generally affordable (~$8 per 453 g, except Juncus, $80 per 453 g) for incorporation into erosion mixtures.

LITERATURE CITED

Allen HH, Pierce GJ, Van Wormer R. 1989. Considerations and techniques for vegetation establishment in constructed wetlands. In: Hammer DA, editor. Constructed Wetlands for Wastewater Treatment. Chelsea (MI): Lewis Publ. p 405-15.

Braun-Blanquet J. 1932. Plant Sociology--The study of Plant Communities. New York (NY): McGraw-Hill. 439 p.

Collins B, Wein G. 1995. Seed bank vegetation of a constructed reservoir. Wetlands 15(4):374-85.

Cox GW. 1996. Laboratory Manual of General Ecology. Dubuque (IA): Wm. C. Brown Publ. 278 p.

Fassett NC. 1969. A Manual of Aquatic Plants. Madison (WI): Univ of Wisconsin Pr. 416 p.

Galatowitsch SM, van der Valk AG. 1995. Natural revegetation during restoration of wetlands in the southern prairie pothole region of North America. In: Wheeler BD, Shaw SC, Fojt WJ, Robertson RA, editors. Restoration of Temperate Wetlands. New York (NY): John Wiley. p 128-42.

Gleason HA, Cronquist A. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Bronx (NY): New York Botanical Garden. 910 p.

Hammer DA. 1997. Creating Freshwater Wetlands. Boca Raton (FL): Lewis Publ.

Hey DL. 2002. Nitrogen farming: harvesting a different crop. Restor Ecol 10(1):1-10.

Luckeydoo LM. 2002. Vegetation and Algal Community Composition and Development of Three Constructed Wetlands Receiving Agricultural Runoff and Subsurface Drainage, 1998 to 2001 [PhD]. Columbus (OH): Ohio State Univ. 261 p.

Luckeydoo LM, Fausey NR, Brown LC, Davis CB. 2002. Early development of vascular vegetation of constructed wetlands in northwest Ohio receiving agricultural waters. Agric Ecosyst Environ 88:89-94

Marble AD. 1992. A Guide to Wetland Functional Design. Boca Raton (FL): Lewis Publ. 240 p.

McAtee WL. 1939. Wildfowl Food Plants. Ames (IA): Collegiate Pr Inc. 141 p.

Mitsch WJ, Day JW Jr, Gilliam JW, Groffman PM, Hey DL, Randall GW, Wang N. 1999. Reducing nutrient loads, especially nitrate-nitrogen, to surface water, ground water, and the Gulf of Mexico. Topic 5: Report for the Integrated Assessment on Hypoxia in the Gulf of Mexico: NOAA Costal Ocean Program; US Dept of Commerce.

Mitsch WJ, Day JW Jr, Gilliam JW, Groffman PM, Hey DL, Randall GW, Wang N. 2001. Reducing nitrogen loading to the Gulf of Mexico from the Mississippi River Basin: strategies to counter a persistent ecological problem. BioScience 51(5):373-88.

Payne NF. 1992. Techniques for Wildlife Habitat Management of Wetlands. New York (NY): McGraw-Hill. 549 p.

Reed PB. 1988. National list of plant species that occur in wetlands: Ohio. Washington (DC): US Dept of the Interior-Fish and Wildlife Service. Report nr NERC-88/18.35.

Sheaffer C, Rose MA. 1998. Native Plants of Ohio. Bull 865, The Ohio State Univ Extension, Columbus, OH. 48 p.

Thunhorst GA. 1993. Wetland Planting Guide for the Northeastern United States. St. Michael's (MD): Environmental Concern. 179 p.

[USFW] United States Fish and Wildlife Service. 1996. National List of Vascular Plant Species that Occur in Wetlands. Kartesz JT (copyright). http://www.nwi.fws.gov/bha/list96.html. Last accessed 19 Aug 2002.

Weinhold CE, van der Valk AG. 1989. The impact of duration of drainage on the seed bank of northern prairie wetlands. Can J Bot 67:1878-84.

Welling CH, Pederson RL, van der Valk AG. 1988. Temporal patterns in recruitment from the seed bank during drawdowns in a prairie wetland. J Appl Ecol 25:999-1007.

(1) Manuscript received 10 November 2004 and in revised form 25 March 2006 (#04-22).

LEE M. LUCKEYDOO, NORMAN R. FAUSEY, CRAIG B. DAVIS, EMILIE REGNIER, AND LARRY C. BROWN, USDA-ARS Soil Drainage Research Unit, 590 Woody Hayes Drive, Columbus, OH 43210; School of Natural Resources, The Ohio State University, 2021 Coffey Road, Columbus, OH 43210; Department of Horticulture and Crop Sciences, The Ohio State University, 2021 Coffey Road, Columbus, OH 43210; Department of Food, Agricultural and Biological Engineering, The Ohio State University, 590 Woody Hayes Drive, Columbus, OH 43210

TABLE 1
List of species and associated species characteristics that were
present in the three constructed wetlands located in northwest Ohio,
1998-2001.

 Species Located in Located at
Species Name (1) Status (2) Zones (3) Sites (4)

Wetland
 Agrostis gigantea Roth. FACW- I W D F
 Aster novae-angliae L. FAC I D
 Atriplex patula L. FACW W F
 Bidens frondosa L. FACW W V
 Carex squarrosa L. FACW I D
 Carex vulpinoidea Michx. OBL I W D V
 Cyperus strigosus L. FACW I W F
 Eleocharis ovata (Roth) OBL I W D V
 Roemer & Schultes.
 Euthamia graminifolia FAC I W D V
 (L.) Nutt.
 Hordeum jubatum L. FAC I W D V
 Juncus effusus L. FACW+ I D
 Juncus tenuis Willd. FAC- I W D V
 Lactuca serriola L. FAC- I W D F V
 Leersia oryzoides OBL I W F V
 (L.) Swartz.
 Lemna minor L. OBL O F
 Lindernia dubia (L) Pennell. OBL W D
 Panicum dichotomiflorum FACW- I W D F V
 Michx.
 Penthorum sedoides L. OBL I V
 Phalaris arundinaceae L. FACW I W F
 Polygonum hydropiper L. OBL W F
 Polygonum lapathifolium L. FACW+ I W F
 Polygonum pensylvanicum L. FACW I W D F V
 Polygonum persicaria L FACW I W O D F V
 Populus deltoides Marshall. FAC I W D F V
 Portulaca oleracea L. FAC I W F
 Potamogeton foliosus Raf. OBL W O D F V
 Rorippa palustris (L.) OBL I W O D F V
 Besser.
 Salix exigua Nutt. OBL I W O D V
 Salix nigra Marshall. FACW+ I W V
 Scirpus atrovirens Willd. OBL I W D V
 Scirpus cyperinus (L.) Kunth. FACW+ I D
 Salix amygaloides Andersson. FACW I F
 Typba angustifolia L. OBL I W O D V
 Verbena hastata L. FACW+ I D
 Xanthimn strumarium L. FAC I W O V

Non wetland
 Abutilon theophrasti Medikus. UPL I W F V
 Acalypha rhomboidea Raf. FACU- I W D V
 Ambrosia artemisiifolia L. FACU I W D F V
 Aster pilosus Willd. UPL I W D V
 Barbarea vulgaris R.Br. FACU I D F
 Bromus intermis Leysser. FACU I W V
 Bromus japonicus Thunb. FACU- 1 W F V
 Cerastium vulgatum L. FACU- W V
 (Chamaesyce) Euphorbia FACU I V
 nutans Lagasca.
 Cichorium intybus L NL I D
 Cirsium altissimum NL I W D F V
 (L.) Sprengel.
 Cirsium arvense (L.) Scop FACU I W D F V
 Dactylis glomerata L. FACU I W D F V
 Daucus carota L. NL I D
 Digitaria sanguinalis FACU- I W D V
 (L.) Scop.
 Echinochloa crusgalli FACU I W O D F V
 (L.) P. Beauv.
 Elytrigia repens (L.) Nevski. FACU- I W F
 Erigeron annuus (L.) Pers. FACU I W D V
 Erigeron strigosus Muhl. FACU+ I W D F V
 Festuca pratensis Hudson. FACU I W D F V
 Lepidium campestre (L.) R.Br. NL I W D F V
 Lolium perenne L FACU- I W D F V
 Medicago sativa L NL I W D V
 Melilotus officinalis FACU- I D V
 (L.) Pallas.
 Phleum pratense L FACU I W D F
 Plantago lanceolata L. UPL I W D F V
 Plantago major L. FACU I W D F V
 Poa annua L. FACU I D
 Polygonum aviculare L. FACU I W I) F
 Potenilla norvegica L. FACU I W D F
 Prunella vulgaris L. FACU I D
 Rumex crispus L. FACU I W D F V
 Setaria faberi R. Herrm. FACU I W O D F V
 Setaria glauca (L) P. Beauv. NL W F
 Solidago canadensis L. FACU I W D V
 Sonchus oleraceus L. UPL I W F V
 Taraxacum officinale FACU- I D V
 Weber ex Wiggers.
 Thaspi arvense L. NL W F
 Trifolium pratense L. FACU- I W D F V
 Trifolium repens L. FACU- I D F V
 Verbena bracteata UPL I W F
 Lagasca & Rodriguez.
 Veronica arvensis L. NL I V

(1) Authority: Gleason and Cronquist 1991

(2) Wetland Indicator status from Reed 1998; USFW 1996: OBL = Obligate,
FACW = Facultative Wetland (67%-99% probability occurrence in
wetlands), FAC = Facultative (35-66% probability occurrence in
wetlands), FACU = Facultative Upland (1-33% probability occurrence in
wetlands), UPL = Obligate Upland species, NL = No listing.

(3) Zones: I = Infrequently submerged, W = Frequently submerged,
O = Open water

(4) Sites: D = Defiance County, F = Fulton County, V = Van Wert County

TABLE 2
Summarized Importance Factor (IF) ranking of species that occurred
greater than or equal to 50% on individual season IF lists during
1998 through 2001 at the studied constructed treatment wetlands in
northwest Ohio.

 Summary Importance Factor 1998-2001

Defiance Fulton

Juncus tenuis Willd. (WIS) Dactylisglomerata L. (PLEC)
Medicago sativa L. (PLEC) Festuca pratensis Hudson. (PLEC)
Salix exigua Nutt. (WIS) Echinochloa crusgalli (L.)
 P. Beauv. (WD/PLEC)
Solidago canadensis L. (WD) Polygonum persicaria L. (WIS)
Phleum pratense L. (PLEC) Phalaris arundinacea L. (WISI)
Echinochloa crusgalli (L.)
 P. Beauv. (WD/PLEC)

 Summary Importance Factor 1998-2001

Defiance Van Wert

juncus tenuis Willd. (WIS) Scirpus atrovirens Willd. (WIS)
Medicago sativa L. (PLEC) Carex vulpinoidea Michx. (WIS)
Salix exigua Nutt. (WIS) Bromus inermis Leysser. (PLEC)

Solidago canadensis L. (WD) Festuca pratensis Hudson. (PLEC)
Phleum pratense L. (PLEC)
Echinochloa crusgalli (L.)
 P. Beauv. (WD/PLEC)

WIS = Wetland indicator species
WISI = Wetland indicator species with invasive rating
PLEC = Planted erosion control on upper bank
WD = Weed species

Authority: Gleason and Cronquist 1991