- CHAPTER 5 - 

 BIOLOGICAL COMPONENTS OF ATLANTIC WHITE CEDAR WETLANDS 



5.1 ADAPTATIONS TO THE WETLAND ENVIRON- 

 MENT 



Plant species growing with the Atlantic white 

 cedar manage to thrive in a waterlogged environ- 

 ment with a varying hydroperiod, and generally 

 acidic, nutrient-poor and often anaerobic soil and 

 water Major physical and physiologic adaptations 

 to this suite of extreme conditions are a hallmark of 

 the biota of the Atlantic white cedar community, but 

 no quantitative work has been published on the sub- 

 ject. Waterlogging and its effects have been exam- 

 ined in bottomland hardwoods (Wharton etal. 1982); 

 physiological adaptation of cells to the acidic milieu 

 is discussed byLevandowsky (1987). Both works in- 

 clude a review of the pertinent literature. 



5.2 FLORA 



5.2.1 Diversity and Distribution of Associated 

 Species 



A relatively accurate picture of cedar wet- 

 land biota may be given by consideration of a com- 

 bination of the most constant species (those most 

 frequently co-occurring with Atlantic white cedar); 

 the total species richness (number of species); and 

 those few that are considered rare, endangered, or 

 of other special regional concern. Plants that fre- 

 quently co-occur are termed "constant companions" 

 or "constant species" (Braun-Blanquet 1932; Braun- 

 Blanquet and Pavillard 1930). 



"Frequency" and "constancy" as used here 

 refer only to the presence of a species in cedar- 

 dominated assemblages and not to abundance of in- 

 dividuals or percent cover. Scientific and common 

 names of all the reported associated vascular flora 

 are recorded in Appendix A. 



The vertical structure and vegetational com- 

 position of cedar wetlands vary with the age of the 

 stand, the history of natural and anthropogenic dis- 



turbance, latitude, altitude, the hydrological regime, 

 geomorphology, and microtopography. In some 

 areas (e.g.. New York's Long Island, New Jersey's 

 Hackensack Meadows) many sites are so disturbed 

 that species defined as constant companions of 

 cedars decades ago are now no longer found with 

 cedars, or are themselves near extirpation (see 

 Chapter 2). 



5.2.2 Constant Companions 



Canopy co-dominants . A monospecific, 

 dense, mature, even-aged stand may have a sparse 

 to nonexistent subcanopy, shrub, herb, or reproduc- 

 tion layer, except at breaks in the canopy and at the 

 edges of the stand (by definition, no other tree oc- 

 cupies the canopy). In mixed stands throughout the 

 cedar's range, the most frequently encountered 

 trees are red maple and black gum. 



Additionally, in the northern states, gray 

 birch {Betula populifolia), black spruce, white pine, 

 and hemlock are most widely distributed. In the mid- 

 dle of the range, sweet bay and a series of oaks 

 {Quercus) and pines (Pinus) supplant most northern 

 species. Further south, bay (Gordonia lasianthus. 

 Persea borbonia, P palustris) and cypress are also 

 frequent canopy or subcanopy associates. 



Shrub layer . Relatively open-canopy cedar 

 stands generally have a well-developed shrub layer 

 More cedar-associated shrubs are in the heath family 

 (Ericaceae) than in any other The most widely dis- 

 tributed shrubs (including woody vines) associated 

 with Atlantic white cedar are red chokecherry (Aronia 

 arbutifolia), sweet pepperbush, bitter gallberry {Ilex 

 glabra), fetterbush (Leucothoe racemosa), swamp 

 honeysuckle, poison ivy {Toxicodendron radicans), 

 poison sumac (I vernix), and highbush blueberry. 



Herbaceous layer . The most abundant her- 

 baceous cover is found with cedar on bog mats and 

 as a temporary feature shortly after disturbance that 

 either eliminates the shrub layer or opens the canopy 



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