ECOLOGY 



The chief ecological factors operating in the Northwest 

 Pocosin are soil nutrients, hydrology and fire, with logging 

 and drainage being overriding and fairly recent additions to 

 the forces affecting the ecosystem. Evidence of fire is com- 

 mon throughout the natural area and its environs , in the form 

 of charred trees and abrupt changes in the character of the 

 vegetation across manmade firebreaks such as roads. The en- 

 tire plant species assemblage is fire adapted: able to sur- 

 vive fires and even promote fire-prone conditions, as well 

 as colonize burned areas, through such mechanisms as trunk 

 and root sprouts, serotinous cones and thick sclerophyllous 

 leaves rich in aromatic compounds (Christensen e_t a^. , 1981) . 

 Christensen e_t al. in their review note also that species 

 diversity in pocosins is greatest immediately after fire. 

 The authors tentatively relate the observed diversity to 

 local variation in the amounts of nutrients released by any 

 given fire, and to effects of fire on microclimate and water 

 availability. The authors conclude that the role of fire "in 

 maintaining species diversity [in pocosins] can not be over- 

 emphasized." ( ibid . , p. 57). 



Soil nutrient availability and hydrology are closely 

 related factors. As noted above, the deepest peats are 

 located in the center of the natural area, becoming gradually 

 more shallow as one moves toward the pocosin edge. This ar- 

 rangement is reflected in the concentric pattern of soil 

 series mapped in Northwest Pocosin: Dare muck-Croatan muck- 

 Paxville mucky fine sandy loam, from center to edge and from 

 deep to shallow organic to mineral soils. The vegetation 

 clearly responds to this factor of peat depth, with the lower 

 communities (high pocosin) in the center of the peat body 

 grading into pond pine woodland and forest in the surrounding 

 shallow peat margins. This pattern follows the general intra- 

 pocosin variation described by Otte (1981) . 



The essence of the pocosin system is that it is nutrient- 

 poor or ombrotrophic (Otte, 1981; Daniel, 1981). The domed 

 peat deposits of the Northwest Pocosin are isolated from any 

 throughflowing water which could carry sediments and nutrients 

 into the system. There is no adjacent high ground (excepting 

 minor areas along Minnesott Ridge to the east) , and no source 

 of overbank flow from streams. Precipitation is the main 

 source of water entering the pocosin, and waterflow is es- 

 sentially out of the pocosin. Additionally, the deeper, 

 wetter peats more effectively isolate plant roots from under- 



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