20240918-005: Austin-Area Freshwater Mussels WPD Presentation — original pdf

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1 Briefing on Occurrence, Distribution, and Protected Status of Austin-Area Freshwater Mussels N I T S U A F O Y T I C Environmental Commission September 18, 2024 Bianca J. Perez WPD Environmental Scientist Bianca.Perez@austintexas.gov W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 2 Introduction • I m p r o ve wa t e r q u a l i t y h a b i t a t • P r o v i d e s t r u c t u r a l • P r o v i d e n u t r i e n t c y c l i n g a n d s t o r a g e • S e n t i n e l s p e c i e s N I T S U A F O Y T I C W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 2 Introduction N I T S U A F O Y T I C • H a b i t a t d e g r a d a t i o n • Impervious cover • E n v i r o n m e n t a l p o l l u t i o n • Anthropogenic pollution • F l o w m a n a g e m e n t / a t t e n u a t i o n • Highland Lakes • I n v a s i v e s p e c i e s • Zebra mussels • Asian clams 3 Zebra mussels Public awareness W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Stream restoration project N I T S U A F O Y T I C 4 Objectives O b t a i n g e n e r a l p o p u l a t i o n i n f o r m a t i o n i n s e l e c t e d m a j o r c r e e k s 1 . D o c u m e n t s p e c i e s p r e s e n c e a n d a b s e n c e , a b u n d a n c e , a n d s i t e c h a r a c t e r i s t i c s O N I 2 . C o m p a r e d i v e r s i t y, e v e n n e s s , a n d d o m i n a n c e i n d i c e s b e t w e e n w a t e r s h e d s W A T E R S H E D P R O T E C T D E P A R T M E N T 5 Legend Headwaters Mid Reaches Lower Reaches Longhorn Dam Study design: Site selection N I T S U A F O Y T I C • M a j o r c r e e k s t h a t c o n f l u e n c e w i t h t h e C o l o r a d o R i v e r d o w n s t r e a m o f t h e L o n g h o r n D a m • 2 1 w a t e r s h e d s t a r g e t e d • S t r a t i f i e d r a n d o m s a m p l i n g • Headwaters to confluence W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Study design: Field surveys 6 N I T S U A F O Y T I C L i z J o h n s t o n , C O A W P D S o m e r l e y S w a r m , U S F W S A s h l e y S e a g r o v e s R u p p e l , U S F W S • J u n- N o v 2 0 1 8 • 8 9 s i t e s v i s i t e d • Vi s u a l a n d t a c t i l e s u r v e y s • S i t e & i n - s t r e a m d a t a c o l l e c t e d • I d e n t i f i e d l i v e a n d r e l i c m u s s e l s W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Results: Environmental parameters 7 FLOW TYPE Flood High Dry N I T S U A F O Y T I C Normal W A T E R S H E D P R O T E C T I O N D E P A R T M E N T No flow Low Results: Environmental parameters 8 pH Dissolved oxygen N I T S U A F O Y T I C Water temperature Conductivity W A T E R S H E D P R O T E C T I O N D E P A R T M E N T N I T S U A F O Y T I C 9 13 Species F M F M W A T E R S H E D P R O T E C T I O N D E P A R T M E N T F M Toxolasma texasiense Amblema plicata Cyclonaias pustulosa Cyrtonaias tampicoensis Lampsilis bracteata Lampsilis teres Potamilus (leptodea) fragilis Pyganodon grandis Quadrula quadrula Toxolasma parvum Uniomerus declivis Uniomerus tetralasmus Utterbackia imbecillis Randklev et al. 2023 10 Results: Mussels by species N I T S U A F O Y T I C Live Relic 66 sites 13 species 535 individuals W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 11 Results: Mussels by species N I T S U A F O Y T I C W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Live Relic Five species account for 92% of all individuals found Results: Mussels by species 12 ES N I T S U A F O Y T I C Live Relic Some species only represented by dead shells W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 13 13 Watershed Cottonwood Decker Dry Creek East Gilleland Maha Marble N I T S U A F O Y T I C W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Watershed North Fork Dry Onion Rinard Slaughter Wilbarger Willow 12 / 21 watersheds had live mussels 14 Results: Relative density N I T S U A F O Y T I C Highest density in Cottonwood, Decker, and Dry East Many watersheds with no mussels detected W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 15 Results: Metric calculation N I T S U A F O Y T I C W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 16 Results: Metric calculation N I T S U A F O Y T I C W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Low diversity 17 Results: Metric calculation N I T S U A F O Y T I C W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Low evenness of species abundances within a community 18 Results: Metric calculation N I T S U A F O Y T I C W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Dominated by one or two species 19 Results: Metric calculation N I T S U A F O Y T I C W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 20 Discussion: the 92% Species Common Name Shell Thickness Lifespan Current Preferences Substrate Preferences Lampsilis teres Yellow Sandshell Thin to moderately thick 13 years Slow to Moderate Persist in Disturbed Environments Age at Sexual Maturity Fecundity Mud and sand Yes 1 year ~500,000 Pyganodon grandis Giant Floater Toxolasma texasiens Texas Lilliput Moderately thick Thin 10 years Silt and mud 1 year ~400,000 Slow or no current 11 years Slow Mud and sand 2 year ~33,000 Uniomerus tetralasmus Pondhorn Moderately Unknown Still to moderate Mud, sand, gravel Unknown Unknown Yes Yes Yes thin to moderately thick Utterbackia imbecillis Paper Pondshell Thin 5 years Slow Yes 1 year ~50,000 Mud and Sand W A T E R S H E D P R O T E C T I O N D E P A R T M E N T N I T S U A F O Y T I C 21 Discussion N I T S U A F O Y T I C Texas Fatmucket Lampsilis bracteata NEWLY LISTED Endangered Species (as of 6/3/24) W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Critical Habitat (USFWS): Lower Onion Creek 21 22 Conclusions N I T S U A F O Y T I C 1. Seeing highest abundance in species that can persist in highly disturbed environments 2. Many watersheds dominated by single species (low diversity and evenness) 3. Evidence of at least one endangered species occurring in Austin W A T E R S H E D P R O T E C T I O N D E P A R T M E N T N I T S U A F O Y T I C 23 Contact Information B i a n c a . P e r e z @ A u s t i n Te x a s . g o v R e p o r t : N a t i v e f r e s h w a t e r m u s s e l d i s t r i b u t i o n i n t r i b u t a r i e s o f t h e C o l o r a d o R i v e r d o w n s t r e a m o f L o n g h o r n D a m n e a r A u s t i n , Te x a s , U S A Wa t e r s h e d P r o t e c t i o n D e p a r t m e n t p u b l i c a t i o n s e a r c h h t t p s : / / s e r v i c e s . a u s t i n t e x a s . g o v / w a t e r s h e d _ p r o t e c t i o n / p u b l i c a t i o n s / d e f a u l t . c f m W A T E R S H E D P R O T E C T I O N D E P A R T M E N T