Wood Ducks 8 1 



We monitored environmental parameters, changes in vegetation, and the 

 response of wood ducks within these blackwater impoundments during the two 

 years following construction and initial inundation. 



STUDY SITES 



The study was conducted on three small blackwater impoundments at 

 Camp Lejeune Marine Base, Onslow County, North Carolina. The impound- 

 ments were located approximately 5 km east of Stone Bay (on the New River) 

 and about 8 km northwest of the Atlantic Ocean. 



Impoundment 1 (hereafter 1-1) covered 1.2 ha with a mean depth of 1 

 m. Black gum (Nyssa sylvatica), red maple (Acer rubrum), sweetgum (Liq- 

 uidambar styraciflua), American holly (Ilex opaca), red bay (Persia borbonia), 

 sweetbay (Magnolia virginiana), and willow (Salix caroliniana) formed a partial 

 canopy over the inundation. Fetterbush (Lyonia lucida), wax myrtle (Myrica 

 cerifera), and titi (Cyrilla racemiflora) furnished a thick undergrowth around and 

 within 1-1. Duckweeds (Spirodela spp., Wolffia spp., Wolfiella spp., and Lemna 

 spp.) blanketed much of the water in spring and summer. 



Impoundment 2 (1-2) covered 1 .9 ha at a mean depth of 1 .5 m. 1-2 was 

 heavily wooded by yellow poplar (Liriodendron tulipifera), sourwood (Oxyden- 

 drum arboreum), water oak (Quercus nigra), American holly, red bay, and sweet- 

 bay. Other woody vegetation included black gum, sweetgum, loblolly pine, fet- 

 terbush, wax myrtle, loblolly bay (Gordonia lasianthus), and white oak (Quer- 

 cus alba). Duckweeds flourished during spring and summer. 



Impoundment 3 (1-3) covered 0.36 ha with a mean depth of 1.5 m. Most 

 of 1-3 was open water, flanked by two wooded coves vegetated with water oak, 

 loblolly pine, wax myrtle, American holly, sourwood, and red maple. Mats of 

 bladderwort (Utricularia biflora) spread across the water, and organic matter 

 supporting herbaceous plants such as yellow-eyed grasses (Xyris spp.) and club 

 moss (Lycopodium alopecuroides) draped floating logs. 



METHODS 



Dissolved oxygen, pH, and Secchi disk readings were recorded month- 

 ly from June 1991 - December 1992 at each impoundment. Vegetation was sam- 

 pled with a series of 15 m 2 circular plots, each selected randomly within a grid at 

 a ratio of one plot per 0.40 ha. of pond surface. Plots were sampled in August 

 1991 and again in June and August 1992. All trees within each plot were count- 

 ed and measured for diameter at breast height (dbh). The number of above- water 

 stems of shrubs and vines was counted, and percent cover of herbaceous vegeta- 

 tion was visually estimated to the nearest 10% in a 0.50-m 2 quadrat. 



Mast was sampled biweekly from September through December 1992 

 in square baskets of 1-m 2 surface area. Ten baskets were placed randomly at each 

 wetland, with the restriction that they were spaced evenly around each wetland. 



