Sumter National Forest Final Report - NatureServe

Alliance: Carex torta Temporarily Flooded Herbaceous Alliance (A.1340)ELEMENT CONCEPTSummary: This association accommodates Carex torta-dominated alluvial wetlands on sand, gravel, and rock bars along riverbanksin valleys and gorges in the southern Appalachians, ranging west into the Cumberland Plateau and the Interior Low Plateau, and northinto the Central Appalachians. This association is characterized by light-requiring, tough-rooted herbaceous perennials tolerant offrequent inundation and flood-scouring. Carex torta often forms dense, extensive colonies. Associated species vary with geographybut can include Verbena hastata, Doellingeria umbellata (= Aster umbellatus), Dichanthelium clandestinum, Solidago rugosa ssp.aspera, Juncus effusus, Scirpus expansus, Scirpus cyperinus, Equisetum arvense, Onoclea sensibilis, Vernonia noveboracensis,Lycopus virginicus, Scutellaria lateriflora, Lobelia cardinalis, Symphyotrichum dumosum (= Aster dumosus), Lycopus virginicus,Osmunda regalis, Hypericum mutilum, Eupatorium fistulosum, Solidago patula, and Salix sericea.Environment: This association occupies boulder and gravel bars on the frequently flooded, active channel shelves of high-gradientrivers and large streams. Along Laurel Fork, flooding duration is probably similar to that documented along Passage Creek inShenandoah County, Virginia, by Hupp (1982). In that drainage, the channel shelf was inundated approximately 15% of the time.Periodic large or severe floods transport and deposit large numbers of cobbles, stones, and even boulders in characteristic bars bothwithin the channel (islands) and along its edges (streambanks). These bars provide a matrix for deposition of finer alluvium andhabitats for the establishment of tough, adaptable herbaceous plants, which in turn stabilize the bars with massive networks ofperennial rootstocks. Regular flood-scouring batters or removes woody plants which take root in these habitats, maintaining opencanopyconditions. These habitats are highly dynamic, with conditions more or less constantly shifting in response to an irregular butpowerful disturbance regime. While some of the bar habitats may be damaged or removed by severe floods, others may accrete or benewly deposited during the same events.Vegetation: Vegetation is characterized by light-demanding, tough-rooted herbaceous perennials tolerant of frequent inundation andflood-scouring. Carex torta is the dominant species and typically forms dense, extensive colonies. Associated species vary withgeography but can include Verbena hastata, Doellingeria umbellata (= Aster umbellatus), Dichanthelium clandestinum, Solidagorugosa ssp. aspera, Juncus effusus var. solutus, Scirpus expansus, Scirpus cyperinus, Equisetum arvense, Onoclea sensibilis,Vernonia noveboracensis, Lycopus virginicus, Scutellaria lateriflora, Lobelia cardinalis, Symphyotrichum dumosum (= Asterdumosus), Osmunda regalis var. spectabilis, Eupatorium fistulosum, Solidago patula, and Hypericum mutilum. Small specimens ofSalix sericea and other woody plants are also frequent.Dynamics: Periodic large or severe floods transport and deposit large numbers of cobbles, stones, and even boulders in characteristicbars both within the channel (islands) and along its edges (streambanks). These bars provide a matrix for deposition of finer alluviumand habitats for the establishment of tough, adaptable herbaceous plants, which in turn stabilize the bars with massive networks ofperennial rootstocks. Regular flood-scouring batters or removes woody plants which take root in these habitats, maintaining opencanopyconditions. These habitats are highly dynamic, with conditions more or less constantly shifting in response to an irregular butpowerful disturbance regime. While some of the bar habitats may be damaged or removed by severe floods, others may accrete or benewly deposited during the same events (Hupp 1982). Successionally, this unit can be considered a pioneering type on new, coarsealluvial land, but it is also more or less permanently maintained by natural disturbances.Similar Associations:• Carex torta - Apocynum cannabinum Herbaceous Vegetation (CEGL006536)Related Concepts:• Carex torta Association (Fleming and Moorhead 1996) ?• Carex torta Herbaceous Vegetation (Fleming and Coulling 2001) ?• IIE3a. Riverside Shoal and Stream Bar Complex (Allard 1990) B• Riverine Upper and Lower Perennial Beach/Bar, Cobble/Gravel, Seasonally Flooded (R2and3BB1C) (Cowardin et al. 1979) ?• Riverine Upper and Lower Perennial Beach/Bar, Sand, Seasonally Flooded (R2and3BB2C) (Cowardin et al. 1979) ?• Rocky Bar and Shore (Twisted Sedge Subtype) (Schafale 1998b) ?• Torturous sedge gravel rivershore (CAP pers. comm. 1998) ?Classification Comments:CONSERVATION RANKING & RARE SPECIESGRank: G3G4 (2000-1-21): This community is found as linear occurrences along waterways in the Southern Appalachians, westinto the Cumberland Plateau and the Interior Low Plateau, and north into the Central Appalachians and Allegheny Mountains.Although this community has a moderately large geographic range, it is uncommon within its range and occurrences are small. Thiscommunity is more common than the number of documented occurrences would suggest, since it is often overlooked in inventories.High-ranked species: No informationELEMENT DISTRIBUTIONRange: This community is found as linear occurrences along waterways in the Southern Appalachians, west into the CumberlandPlateau and the Interior Low Plateau, and north into the Central Appalachians, and Allegheny Mountains.Subnations: AL, DE, GA, KY, NC, SC, TN, VA, WVTNC Ecoregions: 44:C, 50:C, 51:C, 58:C, 59:CVegetation of Sumter National Forest April 30 2004Copyright © 2004 NatureServe96