Sumter National Forest Final Report - NatureServe

CLASS FOREST WOODLAND SHRUBLANDSUBCLASS Deciduous Forest Evergreen Woodland Deciduous ShrublandGROUP Cold-deciduous Forest Temperate or Subpolar Needle-leavedEvergreen WoodlandTemperate Broad-leaved EvergreenShrublandSUBGROUP Natural/Semi-natural Natural/Semi-natural Natural/Semi-naturalFORMATION Lowland or Submontane ColddeciduousSaturated Temperate or Subpolar Needle-Sclerophyllous Temperate Broad-Forestleaved Evergreen Woodlandleaved EvergreenShrublandALLIANCEASSOCIATIONQuercus stellata - Quercusmarilandica Forest AllianceQuercus stellata - Quercusmarilandica – Carya (glabra,texana) / Vaccinium arboreumForestPinus palustris Saturated Woodland AlliancePinus palustris / Leiophyllum buxifolium /Aristida stricta WoodlandQuercus havardii Shrubland AllianceQuercus havardii - (Penstemonambiguus, Croton dioicus) /Sporobolus giganteus ShrublandThe combined physiognomic/floristic system developed by TNC/NatureServe allows identification of units from both a "top-down"(divisive) and "bottom-up" (agglomerative) approach. The top-down approach allows the use of physiognomic distinctions to helpmap vegetation, to stratify sampling, and to delimit vegetation units where floristic information is lacking. A bottom-up approachemploys plot sampling and floristic analysis as the primary means for defining associations. Where physiognomy is variable, thebottom-up approach can also be used to help determine the important physiognomic distinctions. The relationships betweenphysiognomy and floristics are not always simple; when they do not correspond, precedent may be given to the floristic relationshipsover the physiognomic structure.The basic unit of inventory, the plant association or community element, is more or less uniform in structure, composition, andhabitat. The uniformity of the plant community makes the comparison and identification of protection priorities more objective thanwould be possible at more heterogeneous scales. The plant association is a suitable unit for conservation planning because itencompasses all the layers of vegetation in a stand, reflects ecological and human-caused processes including management activities,and is a repeating unit in different landscapes. From a site-based perspective, there may be many different community types at a givenlocation. In fact, it is relatively rare that a site contains only a single community type. However, community elements tend tocombine in predictable ways to create repeatable landscape mosaics. Thus the particular mosaic of community elements present at asite and their distribution across the landscape provide information that is fundamental to any type of ecological land management.The rationale for coupling physiognomic and floristic systems has been developed over the years (e.g., Rubel 1930, Whittaker 1962,Ellenberg 1963, Webb et al. 1970, Westhoff 1967, Beard 1973, Werger and Spangers 1982). These studies have found a good fitbetween floristic and physiognomic classifications of the same vegetation. In the United States, Driscoll et al. (1984) recommendedthe development of a joint system using the physiognomic units of UNESCO (1973) and the floristic units of habitat types, of whichan example has recently been provided by Dick-Peddie (1993) in New Mexico. Vankat (1990) developed a physiognomic-dominancetype classification for forest types in North America. Strong et al. (1990) in Canada also proposed a combined physiognomic-floristicapproach. In addition, Specht et al. (1974) used the joint approach to develop a conservation evaluation for Australian plantcommunities.Terrestrial Vegetation; “Natural” and “Semi-natural” TypesThe TNC physiognomic-floristic classification has been developed for terrestrial vegetation, that is, all upland terrestrial vegetationand all wetland vegetation with rooted vascular plants. In relation to Cowardin et al. (1979), terrestrial includes those portions of thepalustrine, lacustrine, riverine, estuarine, and marine systems that have rooted vegetation. Classification of this vegetation (theTerrestrial System) is distinct from that of unvegetated deep-water habitats (Freshwater and Marine Systems) and unvegetatedsubterranean habitats (Subterranean System), all of which will have their own classification systems (e.g. Lammert et al. 1997).The USNVC includes all existing vegetation, occurring anywhere along the continuum of "natural" to “cultural", but TNC hasemphasized vegetation types that are "natural" since these communities are the focus of biodiversity protection. The classificationsystem separates natural/semi-natural types from cultural types at a certain level in the hierarchy (the formation subgroup, see table 1).Broadly speaking, natural types include a range of naturalness, namely, "natural" (narrowly defined), "semi-natural" and "modified"vegetation, which together reflect differences in anthropogenic disturbance regimes. All natural types occur spontaneously withoutregular human management, maintenance, or planting, and generally have a strong component of native species. More specifically,"natural" vegetation includes plant communities that appear not to have been significantly modified by human activities, and "seminatural"vegetation includes plant communities where the structure of vegetation has been noticeably changed through humanactivities, but where the species composition is unchanged (van der Maarel and Klotzli 1996). In contrast to natural vegetation, then,"cultural" vegetation can be recognized as that which includes planted/cultivated vegetation types. For cultural and modified vegetation,TNC classifies at a much coarser scale than for natural and semi-natural vegetation, but other organizations and agencies may refine thesecoarse units further. To date, most units described with the finest levels in the classification system have been natural and semi-naturalVegetation of Sumter National Forest April 30 2004viiCopyright © 2004 NatureServe