Appendix 1. Names, statues and average abundance (ind. per p-h) for freshwater mussel species present in our study.

Scientific Name / Common Name / State Status / Federal Status / Endemic (Y/N) / Brazos / Colorado / Cypress / Guadalupe / Neches / Nueces / Rio Grande / Sabine / San Antonio / Trinity
Amblema plicata / Threeridge / None / None / N / 13.9 / 28.7 / 7.7 / 13.3 / 2.2 / 0 / 0 / 0.2 / 0.6 / 0.2
Arcidens confragosus / Rock-Pocketbook / None / None / N / 0.03 / 0 / 0 / 0.01 / 0.2 / 0 / 0 / 0.3 / 0 / 0.02
Cyrtonaias tampicoensis / Tampico Pearlymussel / None / None / N / 5.1 / 0.4 / 0 / 0.9 / 0 / 0 / 8.7 / 0 / 0.2 / 0
Fusconaia askewi / Texas Pigtoe / Threatened / None / Y / 0 / 0 / 0.7 / 0 / 5.2 / 0 / 0 / 5.9 / 0 / 0.9
Fusconaia lananensis / Triangle Pigtoe / Threatened / Petitioned / Y / 0 / 0 / 0 / 0 / 1.7 / 0 / 0 / 0 / 0 / 0
Glebula rotundata / Round Pearlshell / None / None / N / 0 / 0 / 0 / 0 / 0.5 / 0 / 0 / 0 / 0 / 0
Lampsilis bracteata / Texas Fatmucket / Threatened / Candidate / Y / 0 / 0.3 / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 0
Lampsilis hydiana / Louisiana Fatmucket / None / None / N / 0 / 0 / 0 / 0.3 / 0.8 / 0 / 0 / 0.3 / 0 / 0
Lampsilis satura / Sandbank Pocketbook / Threatened / None / Y / 0 / 0 / 0 / 0 / 0.3 / 0 / 0 / 0.2 / 0 / 0
Lampsilis teres / Yellow Sandshell / None / None / N / 3.5 / 0.2 / 12 / 0.9 / 0.6 / 4 / 0.2 / 2.7 / 18.3 / 1.6
Leptodea fragilis / Fragile Papershell / None / None / N / 0.2 / 0.1 / 0 / 0 / 0.1 / 0 / 0 / 0.7 / 0 / 0.6
Ligumia subrostrata / Pond Mussel / None / None / N / 0 / 0 / 1.3 / 0 / 0 / 0 / 0 / 0 / 0 / 0
Megalonaias nervosa / Washboard / None / None / N / 0.2 / 0 / 0.7 / 1.7 / 5.5 / 0 / 0.1 / 0.7 / 0 / 0.7
Obliquaria reflexa / Threehorn Watryback / None / None / N / 0 / 0 / 0 / 0 / 3.4 / 0 / 0 / 1.5 / 0 / 6.6
Obovaria jacksoniana / Southern Hickorynut / Threatened / None / N / 0 / 0 / 0 / 0 / 0.04 / 0 / 0 / 0 / 0 / 0
Plectomerus dombeyanus / Bankclimber / None / None / N / 0 / 0 / 21 / 0.04 / 2.0 / 0 / 0 / 0.8 / 0 / 0.1
Pleurobema riddelli / Louisiana Pigtoe / Threatened / Petitioned / Y / 0 / 0 / 0 / 0 / 2.0 / 0 / 0 / 0 / 0 / 0.02
Popenaias popei / Texas Hornshell / Threatened / Candidate / Y / 0 / 0 / 0 / 0 / 0 / 0 / 8.7 / 0 / 0 / 0
Potamilus amphichaenus / Texas Heelsplitter / Threatened / Petitioned / Y / 0 / 0 / 0 / 0 / 0.02 / 0 / 0 / 0.1 / 0 / 0.1
Potamilus metnecktayi / Salina Mucket / Threatened / Petitioned / Y / 0 / 0 / 0 / 0 / 0 / 0 / 1.0 / 0 / 0 / 0
Potamilus ohiensis / Pink Papershell / None / None / N / 0.1 / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 0
Potamilus purpuratus / Bleufer / None / None / N / 0 / 0 / 0 / 0 / 0.8 / 0 / 0.4 / 1.5 / 0 / 1.6
Pyganodon grandis / Giant Floater / None / None / N / 0 / 0 / 1.7 / 0.1 / 0.1 / 0 / 0 / 0.1 / 0 / 0.2
Quadrula apiculata / Soutehrn Mapleleaf / None / None / N / 1.0 / 0.1 / 0 / 0.1 / 0.9 / 0 / 2.0 / 3.5 / 0 / 1.8
Quadrula aurea / Golden Orb / Threatened / Candidate / Y / 0 / 0 / 0 / 5.6 / 0 / 3 / 0 / 0 / 5.5 / 0
Quadrula houstonensis / Smooth Pimpleback / Threatened / Candidate / Y / 4.8 / 3.7 / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 0
Quadrula mortoni / Western Pimpleback / None / None / N / 0 / 0 / 1 / 0 / 13.9 / 0 / 0 / 2.2 / 0 / 4.4
Quadrula nobilis / Gulf Mapleleaf / None / None / N / 0 / 0 / 0 / 0 / 0.2 / 0 / 0 / 0 / 0 / 1.7
Quadrula petrina / Texas Pimpleback / Threatened / Candidate / Y / 0 / 0 / 0 / 0.3 / 0 / 0 / 0 / 0 / 0 / 0
Quadrula quadrula / Mapleleaf / None / None / N / 0 / 0 / 7.3 / 0 / 0 / 0 / 0 / 0 / 0 / 0
Quadrula verrucosa / Pistolgrip / None / None / N / 0 / 0 / 0 / 0.6 / 4.9 / 0 / 0 / 10.6 / 0 / 1.1
Strophitus undulatus / Squawfoot / None / None / N / 0 / 0 / 0 / 0 / 0.1 / 0 / 0 / 0 / 0 / 0
Toxolasma parvus / Lilliput / None / None / N / 0 / 0 / 0 / 0 / 0.01 / 0 / 0 / 0.01 / 0 / 0
Toxolasma texasense / Texas Lilliput / None / None / N / 0 / 0.2 / 1 / 0 / 0.4 / 0 / 0 / 0 / 0 / 0
Truncilla cognata / Mexican Fawnsfoot / Threatened / Petitioned / Y / 0 / 0 / 0 / 0 / 0 / 0 / 0.3 / 0 / 0 / 0
Truncilla donaciformis / Fawnsfoot / None / None / N / 0 / 0 / 0 / 0 / 0.05 / 0 / 0 / 0 / 0 / 0
Truncilla macrodon / Texas Fawnsfoot / Threatened / Candidate / Y / 0.04 / 0.7 / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 0
Truncilla truncata / Deertoe / None / None / N / 0 / 0 / 0 / 0 / 2.5 / 0 / 0 / 1.9 / 0 / 0.3
Uniomerus declivis / Tapered Pondhorn / None / None / N / 0 / 0 / 0 / 0.03 / 0.1 / 0 / 0 / 0 / 0 / 0.02
Utterbackia
imbecillis / Paper Pondshell / None / None / N / 0.04 / 0 / 0 / 0 / 0 / 0 / 0.1 / 0.01 / 0 / 0
Villosa lienosa / Little Spectaclecase / None / None / N / 0 / 0 / 0 / 0 / 0.04 / 0 / 0 / 0 / 0 / 0

Appendix 2. Presence (indicated by an “x”)/absence data of fish genera in the river basins used in the analysis (where mussels were present).

Genus / Brazos / Colorado / Cypress / Guadalupe / Neches / Nueces / Rio Grande / Sabine / San Antonio / Trinity
Agonostomus / x / x
Alosa / x
Ameiurus / x / x / x / x / x / x / x / x / x
Amia / x / x
Ammocrypta / x / x
Anchoa / x / x
Anguilla / x / x / x
Aphredoderus / x / x / x / x / x / x / x
Aplodinotus / x / x / x / x / x / x / x
Astyanax / x / x / x / x / x / x
Atractosteus / x / x / x / x / x / x
Brevoortia / x
Campostoma / x / x / x / x / x / x / x / x
Carpiodes / x / x / x / x / x / x / x
Centrarchus / x / x / x
Citharichthys / x
Ctenogobius / x
Ctenopharyngodon / x / x
Cyprinella / x / x / x / x / x / x / x / x / x / x
Cyprinodon / x / x
Cyprinus / x / x / x / x / x / x / x / x
Dionda / x / x / x / x
Dorosoma / x / x / x / x / x / x / x / x / x
Elassoma / x / x / x / x / x
Elops / x
Erimyzon / x / x / x
Esox / x / x / x / x / x
Etheostoma / x / x / x / x / x / x / x / x / x / x
Fundulus / x / x / x / x / x / x / x / x / x
Gambusia / x / x / x / x / x / x / x / x / x / x
Gobiosoma / x
Herichthys / x / x / x / x / x / x
Hybognathus / x / x / x / x
Hybopsis / x / x / x
Hypostomus / x / x
Ichthyomyzon / x / x
Ictalurus / x / x / x / x / x / x / x / x / x
Ictiobus / x / x / x / x / x / x / x / x
Labidesthes / x / x / x / x / x
Lagodon / x
Lepisosteus / x / x / x / x / x / x / x / x / x
Lepomis / x / x / x / x / x / x / x / x / x / x
Lucania / x / x
Luxilus / x
Lythrurus / x / x / x / x / x / x / x / x
Macrhybopsis / x / x / x / x / x / x
Menidia / x / x / x / x / x / x / x
Microgobius / x
Micropogonias / x
Micropterus / x / x / x / x / x / x / x / x / x / x
Minytrema / x / x / x / x
Morone / x / x / x / x / x / x / x
Moxostoma / x / x / x / x / x / x / x / x / x
Mugil / x / x / x / x
Notemigonus / x / x / x / x / x / x / x
Notropis / x / x / x / x / x / x / x / x / x / x
Noturus / x / x / x / x / x / x / x / x
Opsopoeodus / x / x / x / x / x / x / x
Oreochromis / x / x / x
Paralichthys / x
Percina / x / x / x / x / x / x / x / x
Phenacobius / x / x
Pimephales / x / x / x / x / x / x / x / x / x / x
Poecilia / x / x / x / x / x
Pomoxis / x / x / x / x / x / x / x / x / x
Pylodictis / x / x / x / x / x / x / x / x / x
Semotilus / x / x / x
Strongylura / x
Syngnathus / x
Tilapia / x
Trinectes / x / x

Appendix 3. Stream Gauge Information.

Gauge / Name / River / River Basin / Relative Location / Period / Drainage Area (mi2) / Drainage Area (km2) / Influenced by Dams
8188500 / San Antonio Rv at Goliad, TX / San Antonio / SA / Mid San Antonio River / 1940-2014 / 3921 / 10155 / Yes
8181800 / San Antonio Rv nr Elmendort, TX / San Antonio / SA / Mid San Antonio River / 1963-2014 / 1743 / 4514 / Yes
8183500 / San Antonio Rv nr Falls City, TX / San Antonio / SA / Lower San Antonio River / 1926-2014 / 2113 / 5473 / Yes
8186000 / Cibolo Ck nr Falls City, TX / Cibolo Creek / SA / Tributary San Antonio River / 1992-2015 / 827 / 2142 / Yes
8175800 / Guadalupe Rv at Cuero, TX / Guadalupe / GR / Lower Guadalupe River / 1964-2014 / 4934 / 12779 / Yes
8176500 / Guadalupe Rv at Victoria, TX / Guadalupe / GR / Lower Guadalupe River / 1935-2014 / 5198 / 13463 / Yes
8168500 / Guadalupe Rv abv Comal Rv at New Braunfels, TX / Guadalupe / GR / Mid Guadalupe River / 1928-2014 / 1518 / 3932 / Yes
8167000 / Guadalupe Rv at Comfort, TX / Guadalupe / GR / Upper Guadalupe River / 1940-2014 / 839 / 2173 / Yes
8172000 / San Marcos Rv at Luling, TX / San Marcos / GR / Tributary Guadalupe River / 1940-2014 / 838 / 2170 / Yes
8161000 / Colorado Rv at Columbus, TX / Colorado / CO / Lower Colorado River / 1917-2014 / 41640 / 107847 / Yes
8162000 / Colorado Rv at Wharton, TX / Colorado / CO / Lower Colorado River / 1939-2014 / 42003 / 108787 / Yes
8147000 / Colorado RV nr San Saba, TX / Colorado / CO / Mid Colorado River / 1924-2014 / 31217 / 80852 / Yes
8126380 / Colorado Rv nr Ballinger, TX / Colorado / CO / Upper Colorado River / 1908-2014 / 16358 / 42367 / Yes
8151500 / Llano Rv at Llano, TX / Llano / CO / Tributary Colorado River / 1940-2014 / 4192 / 10857 / Yes
8150700 / Llano RV nr Mason, TX / Llano / CO / Tributary Colorado River / 1969-2014*1 / 3247 / 8410 / Yes
8114000 / Brazos Rv at Richmond, TX / Brazos / BR / Lower Brazos River / 1923-2014 / 45107 / 116827 / Yes
8098290 / Brazos Rv nr Highbank, TX / Brazos / BR / Mid Brazos River / 1966-2014 / 30436 / 78829 / Yes
8093100 / Brazos Rv nr Aquilla, TX / Brazos / BR / Mid Brazos River / 1939-2014 / 27244 / 70562 / Yes
8065350 / Trinity Rv nr Crockett, TX / Trinity / TR / Mid Trinity River / 1964-2014 / 13911 / 36029 / Yes
8062500 / Trinity Rv nr Rosser, TX / Trinity / TR / Upper Trinity River / 1939-2014 / 8147 / 21101 / Yes
8055500 / Elm Fk Trinity Rv nr Carrollton, TX / Trinity / TR / Upper Trinity River / 1907-2014 / 2459 / 6369 / Yes
8036500 / Angelina Rv nr Alto, TX / Angelina / NE / Tributary Neches River / 1960-2014 / 1276 / 3305 / Yes
8032000 / Neches Rv nr Neches, TX / Neches / NE / Upper Neches River / 1940-2014 / 1145 / 2966 / Yes
8041500 / Village Ck nr Kountze, TX / Village Creek / NE / Tributary Neches River / 1940-2014 / 860 / 2227 / Yes
8020000 / Sabine Rv nr Gladewater, TX / Sabine / SB / Mid Sabine River / 1933-2014 / 2791 / 7229 / Yes
8020900 / Sabine Rv bl Longview, TX / Sabine / SB / Mid Sabine River / 1996-2014*2 / 3155 / 8171 / Yes
8022040 / Sabine Rv nr Beckville, TX / Sabine / SB / Mid Sabine River / 1940-2014 / 3589 / 9295 / Yes
8017410 / Sabine Rv nr Wills Point, TX / Sabine / SB / Upper Sabine River / 1971-2014 / 756 / 1958 / Yes
8451800 / Rio Grande at Del Rio, TX / Rio Grande / RG / Mid Rio Grande / 1968-2011 / ~123143 / ~318939 / Yes
8458000 / Rio Grande at Eagle Pass, TX / Rio Grande / RG / Mid Rio Grande / 1924-2011*3 / ~128806 / ~333606 / Yes
8459000 / Rio Grande at Laredo, TX / Rio Grande / RG / Lower Rio Grande / 1923-2011 / ~134575 / ~348546 / Yes
8449400 / Devils Rv at Pafford Crossing nr Comstock, TX / Devils River / RG / Tributary Rio Grande / 1960-2011 / ~4246 / ~10996 / /
*1 Missing data 01/01/1993 – 12/31/1997
*2 Interpolated data 12/18/2014 – 12/31/2014
*3 Interpolated data 02/06/1989 – 02/20/1989
~ indicates approximate value

Appendix 4. Flow duration curves (FDSs) for stream gauges organized by basin.

Sabine

FDC Sabine Rv nr Gladwater, TX,FDC Sabine River bl Longview, TX

Mid Sabine River (1933-2014)Mid Sabine River (1996-2014)

FDC Sabine Rv nr Beckville, TXFDC Sabine Rv nr Wills Point, TX,

Mid Sabine River (1940-2014)Upper Sabine River (1971-2014)

Neches

FDC Neches Rv nr Neches, TX, FDC Village Creek nr Kountze, TX,

Upper Neches River (1940-2014) Tributary Neches River (1940-2014)

FDC Angelina River nr Alto, TX,

Tributary Neches River (1950-2014)

Trinity

FDC Trinity Rv nr Crockett, TX,FDC Trinity Rv nr Rosser, TX

Mid Trinity River (1964-2014)Upper Trinity River (1939-2014)

FDC Elm Fk Trinity Rv nr Carrollton, TX

Upper Trinity River (1907-2014)

Brazos

FDC Brazos Rv at Richmond, TXFDC Brazos Rv nr Highbank, TX,

Lower Brazos River (1923-2014)Mid Brazos River (1966-2014)

FDC Brazos Rv nr Aquilla, TX

Mid Brazos River (1939-2014)

Colorado

FDC Colorado Rv at Columbus, TX,FDC Colorado Rv at Wharton, TX,

Lower Colorado River (1923-2014)Lower Colorado River (1939-2014)


FDC Colorado Rv nr San Saba, TX,FC Colorado Rv nr Ballinger, TX,

Mid Colorado River (1924-2014)Upper Colorado (1908-2014)

FDC Llano Rv at Llano, TX,FDC Llano Rv nr Mason, TX,

Tributary Colorado River (1940-2014)Tributary Colorado (1969-2014)

Guadalupe

FDC Guadalupe Rv at Cuero, TXFDC Guadalupe Rv at Victoria, TX

Lower Guadalupe River (1964-2014)Lower Guadalupe River (1935-2014)

FDC Guadalupe Rv abv Comal, TXFDC Guadalupe Rv at Comfort, TX

Mid Guadalupe River (1928-2014)Upper Guadalupe River (1940-2014)

FDC San Marcos Rv at Luling, TX

Tributary Guadalupe River (1940-2014)

San Antonio

FDC San Antonio Rv at Goliad, TXFDC San Antonio Rv nr Elmerdort, TX

Mid San Antonio River (1940-2014)Mid San Antonio River (1963-2014)

FDC San Antonio Rv nr Falls City, TXFDC Cibolo Ck nr Falls City, TX

Lower San Antonio River (1926-2014)Tributary San Antonio (1992-2014)

Rio Grande

FDC Rio Grande at Del Rio, TXFDC Rio Grande at Eagle Pass, TX

Mid Rio Grande River (1968-2011)Mid Rio Grande River (1924-2011)

FDC Rio Grande at Laredo, TXFDC Devils Rv at Pafford Crossing

Lower Rio Grande River (1923-2011)nr Comstock, TX

Tributary Rio Grande River (1960-2014)