Ecoregions of Texas, AS-199 - Texas Commission on Environmental ...

ABSTRACT<strong>Ecoregions</strong> denote areas <strong>of</strong> general similarity in ecosystems and in the type, quality, and quantity <strong>of</strong>environmental resources. Ecoregion frameworks are valuable tools for environmental research, assessment,management, and monitoring <strong>of</strong> ecosystems and ecosystem components. They have been used for settingresource management goals, developing biological criteria and establishing water quality standards. In acooperative project with the <strong>Texas</strong> <strong>Commission</strong> on Environmental Quality, the U.S. Environmental ProtectionAgency, the U.S. Department <strong>of</strong> Agriculture, and other interested state and federal agencies, we have definedecological regions <strong>of</strong> <strong>Texas</strong> at two hierarchical levels that are consistent and compatible with the U.S. EPAecoregion framework. Twelve level III ecoregions and 56 level IV ecoregions have been mapped for <strong>Texas</strong>.These general purpose regions are useful to help structure and implement ecosystem management strategiesacross federal agencies, state agencies, and nongovernmental organizations that are responsible for differenttypes <strong>of</strong> resources within the same geographical areas. Aquatic biologists in <strong>Texas</strong> have a long history <strong>of</strong>analyzing streams and potential reference conditions within a variety <strong>of</strong> <strong>Texas</strong> regional frameworks. Thisecoregion framework was the result <strong>of</strong> input from a variety <strong>of</strong> disciplines, both terrestrial and aquatic based,and takes a broader ecological perspective than just water quality or aquatic macroinvertebrates. We believethat this new ecoregion framework still provides a valuable tool for the State’s water quality assessments.Streams that are representative <strong>of</strong> an ecoregion and are minimally disturbed and least impacted from pointand nonpoint source pollution can serve as suitable reference streams. <strong>Ecoregions</strong> and reference watershedscan be used together to better understand regional variations in stream quality, assess attainable conditions,develop biological criteria, and augment the watershed management approach.ACKNOWLEDGEMENTSMany people contributed to the organization <strong>of</strong> this project and to the development <strong>of</strong> the <strong>Texas</strong> ecoregionframework. For their collaboration and contributions, special thanks are given to Anne Rogers (TCEQ), BillHarrison (TCEQ), Stephen Hatch (<strong>Texas</strong> A&M University), David Bezanson (Natural Area PreservationAssociation), Jeffrey Comstock (Indus Corporation), Philip Crocker (USEPA), Art Crowe (TCEQ), MichaelGolden (NRCS), Susan Casby-Horton (NRCS), James Greenwade (NRCS), Conrad Neitsch (NRCS), ShannenChapman (Dynamac Corporation), Augie De La Cruz (TCEQ), Kevin Wagner (<strong>Texas</strong> State Soil and WaterConservation Board [TSSWCB]), Richard Egg (TSSWCB), Alan Woods (Oregon State University), ClarkHubbs (University <strong>of</strong> <strong>Texas</strong>), David Certain (The Nature Conservancy) and Thomas Loveland (USGS). Thesepeople were authors or collaborators <strong>of</strong> the multi-agency <strong>Texas</strong> ecoregion poster published by the USGS(Griffith et al., 2004). Thanks are also given to the reviewers <strong>of</strong> the ecoregion poster, including CharlesHallmark (<strong>Texas</strong> A&M University), Gordon Linam (TPWD), Milo Pyne (NatureServe), and RaymondTelfair, II (TPWD).To obtain larger, color maps <strong>of</strong> the Level III and IV ecoregions <strong>of</strong> <strong>Texas</strong> or for an ARC/INFO export file <strong>of</strong> theecoregion boundaries, contact the authors or see www.epa.gov/wed/pages/ecoregions/tx_eco.htm.ii<strong>Ecoregions</strong> <strong>of</strong> <strong>Texas</strong>