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A3842 Celtis laevigata - Ulmus crassifolia / Urvillea ulmacea Tamaulipan Riparian Scrub Alliance

The U.S. National
Vegetation Classification
Type Concept Sentence: This forest and woodland alliance is characterized by Celtis laevigata var. laevigata, Ulmus crassifolia, Salix nigra, and Fraxinus berlandieriana occurring in a variety of floodplain settings in the Tamaulipan region of Texas and Mexico.
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Common (Translated Scientific) Name: Sugarberry - Cedar Elm / Apaac Tamaulipan Riparian Scrub Alliance
Colloquial Name: Tamaulipan Sugarberry - Cedar Elm Riparian Scrub
Hierarchy Level: Alliance
Type Concept: This alliance occurs in a variety of floodplain settings in the Tamaulipan region of Texas and Mexico. The canopy is dominated and typified by Celtis laevigata var. laevigata, Ulmus crassifolia, Salix nigra, and Fraxinus berlandieriana. Other canopy species include Sapindus saponaria var. drummondii, Leucaena pulverulenta, Prosopis glandulosa var. glandulosa, and Taxodium mucronatum. The subcanopy is often poorly defined, including a mixture of subtropical and temperate species such as Diospyros texana, Baccharis neglecta, Sideroxylon celastrinum, Xylosma flexuosa, Celtis ehrenbergiana, and Acacia greggii var. wrightii. Lianas are Serjania brachycarpa, Cocculus diversifolius, Clematis drummondii, Urvillea ulmacea, Toxicodendron radicans, Smilax bona-nox, Vitis mustangensis and Cardiospermum halicacabum. Epiphytes are typically abundant, including Tillandsia usneoides, Tillandsia recurvata, and (rarely) Tillandsia baileyi. Characteristic herbs and low shrubs are Rivina humilis, Chromolaena odorata, Capsicum annuum var. glabriusculum, Malpighia glabra, Petiveria alliacea, Celosia nitida, Plumbago scandens, Achyranthes aspera, Solanum triquetrum, and Salvia coccinea. Woodland examples occur on terraces and may have well-developed grassy ground flora characterized by Elymus virginicus, along with Chasmanthium latifolium, and Nassella leucotricha. Variations in floodplain landform and hydrology (river margins, alluvial flats, resacas, levees, terraces) correspond to variations in dominance patterns corresponding to associations in this alliance.
Diagnostic Characteristics: This alliance is characterized by Celtis laevigata var. laevigata, Ulmus crassifolia, Salix nigra, and Fraxinus berlandieriana occurring in a variety of floodplain settings in the Tamaulipan region of Texas and Mexico.
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: This alliance is centered on the Rio Grande delta with some associations extending into adjacent regions. It is a mixture of subtropical and temperate species. It is fraught with extreme loss of occurrences (<10% of former extent of remains), and a lack of good rangewide plot data. Data gaps could represent undescribed associations. Its concept and group placement need a broader review in the context of other temperate and subtropical vegetation that could have similar composition. No characteristic species have been identified, and while there could be some differential species, they are not the dominants. Several species in this alliance have very limited distribution in the U.S.; however, their distribution in Mexico has not been assessed. This vegetation once occupied a large delta region and the mixture of temperate, desert, and subtropical species appears unique.
Similar NVC Types:
Physiognomy and Structure: This floodplain vegetation varies from forests with to woodlands. Epiphytes are typically abundant.
Floristics: The canopy of this alliance is dominated and typified by Celtis laevigata var. laevigata, Ulmus crassifolia, Salix nigra, and Fraxinus berlandieriana. Canopy closure ranges from open to closed. Other canopy species include Sapindus saponaria var. drummondii, Leucaena pulverulenta, Prosopis glandulosa var. glandulosa, and Taxodium mucronatum (= Taxodium distichum var. mexicanum). The subcanopy is often poorly defined, including a mixture of subtropical and temperate species such as Diospyros texana, Baccharis neglecta, Sideroxylon celastrinum, Xylosma flexuosa, Celtis ehrenbergiana, and Acacia greggii var. wrightii (= Acacia wrightii). Lianas are Serjania brachycarpa, Cocculus diversifolius, Clematis drummondii, Urvillea ulmacea, Toxicodendron radicans, Smilax bona-nox, Vitis mustangensis and Cardiospermum halicacabum. Epiphytes are typically abundant, including Tillandsia usneoides, Tillandsia recurvata, and (rarely) Tillandsia baileyi. Characteristic herbs and low shrubs are Rivina humilis, Chromolaena odorata (= Eupatorium odoratum), Capsicum annuum var. glabriusculum, Malpighia glabra, Petiveria alliacea, Celosia nitida, Plumbago scandens, Achyranthes aspera, Solanum triquetrum, and Salvia coccinea. Woodland examples occur on terraces, and may have a well-developed grassy ground flora characterized by Elymus virginicus, along with Chasmanthium latifolium, and Nassella leucotricha. Variations in floodplain landform and hydrology (river margins, alluvial flats, resacas, levees, terraces) correspond to variations in dominance patterns corresponding to associations in this alliance.
Dynamics: Floodplain natural processes once helped to maintain this alliance, but these processes no longer function at historical levels. Much of the floodplain forest in this area has been cleared for agriculture, but many large remnant examples of this alliance are protected, at least from direct destruction. The disruption of natural hydrologic regimes by upstream flood-control structures and irrigation systems presents a long-term threat to the viability of this alliance.
Environmental Description: This alliance occurs in a variety of floodplain settings (river margins, alluvial flats, resacas, levees, terraces) and corresponding soil types.
Geographic Range: This alliance occurs in the coastal plain of the Tamaulipan region of Texas and Mexico.
Nations: MX, US
States/Provinces: MXTM, TX
US Forest Service Ecoregions (1994/1995)
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Confidence Level: Low
Confidence Level Comments:
Grank: GNR
Greasons:
Name:Database Code:Classification Code:
Class 1 Forest & Woodland C01 1
Subclass 1.B Temperate & Boreal Forest & Woodland S15 1.B
Formation 1.B.3 Temperate Flooded & Swamp Forest F026 1.B.3
Division 1.B.3.Nd Western North American Interior Flooded Forest D013 1.B.3.Nd
Macrogroup M036 Interior Warm & Cool Desert Riparian Forest M036 1.B.3.Nd.2
Group G549 Tamaulipan Riparian Scrub Forest G549 1.B.3.Nd.2.a
Alliance A3842 Tamaulipan Sugarberry - Cedar Elm Riparian Scrub A3842
Association CEGL007782 CEGL007782
Association CEGL007752 CEGL007752
Association CEGL007754 Lower Rio Grande Valley Black Willow Forest CEGL007754
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Synonomy: >< Sugarberry-Elm Series (Diamond 1993)
Concept Author(s): J. Teague, in Faber-Langendoen et al. (2013)
Author of Description: J. Teague
Acknowledgements: We have incorporated significant descriptive information previously compiled by A.S. Weakley and B. Carr.
Version Date: 18Dec2014
References:
  • Diamond, D. D. 1993. Classification of the plant communities of Texas (series level). Unpublished document. Texas Natural Heritage Program, Austin. 25 pp.
  • Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.