126 John F. Pagels, Leonard A. Smock and Stephen H. Sklarew 



physico-chemical characteristics of the streams where S. palustris was found in 

 Virginia, 1974-1993. 



Parameter 



Mean 



SE 



Range 



Stream order 



1 



<0.1 



1-2 



Elevation (m) 



1,000 



37 



902-1,128 



Channel gradient (%) 



10 



1.4 



7-14 



Channel width (m) 



4 



0.7 



2-10 



Wetted width (m) 



3 



0.4 



1-7 



Water depth (cm) 



8 



1.3 



1-1,510 



Water velocity (m3/s) 



0.15 



0.01 



0-0.80 



Bank undercut (cm) 



18 



0.5 



0-99 



Wood volume (m3/m 2 ) 



0.53 



0.1 



0.37-0.66 



Debris dams (#/100m) 



3 



0.9 



2-6 



pH 



7.0 



0.1 



6.7-7.2 



Conductivity (uS/cm) 



24 



9 



12-52 



existed in the streams, as reflected by the ranges in water velocity and depths 

 (Fig. 2). Also, although riffles were the predominant habitat (Fig. 3), a distinct 

 riffle-pool geomorphology occurred in all of the streams. 



In-stream cover was abundant in all streams. Cobble was the predomi- 

 nant substrate, with boulder, pebble and gravel also being relatively common 

 (Fig. 3). The sediment was well sorted, with little embeddedness by fine-grained 

 particles (Table 5). Woody debris and resulting debris dams were common in the 

 channels of all streams, and growth of moss in the channel was evident at most 

 sites. 



The riparian areas of the streams were undisturbed, vegetated, and sta- 

 ble (Table 5). All channel banks had extensive undercut areas (Fig. 4) and areas 

 that were rocky with many crevices and downed wood. Most of the undercuts 

 were not in contact with the flowing stream but rather with dry channel sediment. 

 One site had a broad floodplain and many side channels where water flowed 

 freely through interstitial areas in the rocky floodplain floor. 



Yellow birch {Betula luted) was the most abundant canopy tree along 

 the riparian areas of all streams (Table 6). Other common canopy species along 

 the streams were black birch (B. lenta), sugar maple (Acer saccharum), bass- 

 wood (Tilea americana), black cherry (Prunus serotina), red maple (A. rubrum), 

 American beech (Fagus grandifolia), and Eastern hemlock (Tsuga canadensis). 

 The understory was generally undeveloped, typical of mature forests. 



