HYDROPHYTIC VEGETATION CRITERION 



1989 MANUAL: 



Requires under normal circumstances: 1) more than 50% of the composition of 

 the dominant species from all strata are obhgate wetland, facultative wetland, 

 and/or facultative wetland species; OR 2) the prevalence index approach (that is, 

 under normal circumstances, a frequency analysis of all species within the 

 community yields a prevalence index value of less than 3.0 (where OBL = 1.0, 

 FACW = 2.0, FAC = 3.0, FACU = 4.0, and UPL = 5.0). 



PROPOSED REVISED MANUAL: 



Proposes the prevalence index approach - that is, an area meets this criterion if, 

 under normal circumstances, a frequency analysis of all species within the 

 community yields a prevalence index value of less than 3.0 (where OBL = 1.0, 

 FACW = 2.0, FAC = 3.0, FACU = 4.0, and UPL = 5.0). 



Solicits comments on including the Facultative Neutral test as part of the 

 hydrophytic vegetation criterion in addition to the proposed prevalence index 

 approach. Under this approach the criterion would be met if after discounting 

 all dominant facultative (FAC) plants, the number of dominant obhgate wetland 

 (OBL) and facultative wetland (FACW) species exceeds the number of dominant 

 facultative upland (FACU) and obUgate upland (UPL) species. (Note: a number 

 of options are presented describing circumstances under which the prevalence 

 index procedure would be used.) 



Solicits comments on variants of the FAC neutral test. 



