Freshwater Mussels in the Lower Flint River Basin: Recent and Historical Trends

1) Why should we care?

2) Status of Freshwater Mussels in the ACF

3) Where are we now?

Overview

Why Should We Care about Freshwater Mussels?

• Economic importance (historical)• Water purification• Some species indicators of stream health• Improve fisheries

Thar beMussels !

Mussels are FilterFeeders

3 to 6 gal per day per individual

Freshwater Mussel Beds

100 mussels = 0.001 cfs(this image contains 247)

Freshwater Mussel Beds are Foraging Sites

Per

cent

0

10

20

30

40

50

60

Mussels Snails Crayfish Amphibians Fishes

Imperiled North American FreshwaterAnimal Species

Imperiled = Threatened or endangered throughout their historical range.

Neves et al. 1997. Status of aquatic mollusks in the southeaastern US: a downward spiral of diversity. In George W. Benx and David E. Collins editors. Aquatic Fauna in Peril: the Southeastern Perspective. Lenz Design and Communications, Decatur, GA. 554 pp.

Southeastern Mussel Diversity

Lower Flint River and Tributaries

Status of Mussels in the lower Flint River Basin

MusselsFat three-ridge (E)Chipola slabshell (T)Purple bankclimber (T)Shiny-rayed pocketbook (E)Gulf moccasinshell(E)Oval pigtoe (E)

FishGulf sturgeon (T)

Most (remaining) habitat is in the Flint and Apalachicola.

Critical Habitat for the ACF

Flint River Mussel Studies 1950’sW.J. Clench and R.D. Turner

Number of Species

0 10 20 30 40

Total Species Endemic Species

Suwannee

Ochlockonee

Apalachicola

Choctawhatchee

Escambia

River Basin

- Recognized high diversity of the ACF River Basin- Summarized localities of type specimens- Noted declines in the Chattahoochee river

Flint River Mussel Studies 1991-1992 J. Brim Box and J.D. Williams

- 134 sites sampled- 22 species observed

- Kinchafoonee, Muckalee, and Chickasawhatchee Creeks had very high mussel richness (9-16 species)

- Very few mussels observed in the Chattahoochee Basin

1991-1992 sites

Surveying historic mussel populations

Examining responses to drought

Flint River MusselFlint River MusselStudies 1999-2001Studies 1999-2001

Jones Research CenterJones Research Center

1999 Mussel Survey

- 46 sites on 12 tributaries

-Visual and tactile search for mussels

- 100 m sampling areas

1999 Mussel Survey Results

- 14,873 mussels- 19 species - 3 endangered species

Shiny-rayedPocketbook

GulfMoccasinshell

Oval pigtoe

1999 Mussel Survey Conclusions

- Abundant mussel populations still occur

- Endangered species are not abundant

- Tributary streams continue to support the greatest richness and abundance

Muckalee

Kinchafoonee

Chickasawhatchee

Mussel Response to Drought 2000

Prior drought studies:- ?- ?

Summer 2000 Drought Severity

Dewatered stream

Anoxic stream

Results of the 2000 Drought Study

- stagnation accelerated mussel mortality

D.O. < 5 mg/Lvelocity < 0.1 m/sec

- mid-reaches of tributaries were most affected

- drought tolerance varies by species

2001 Mussel Resurvey

Objectives:

1) Determine the extent of regional changes in mussel assemblages due to the drought

2) Determine stream reaches likely to be adversely affected by drought

Site Selection

Criteria for Selection

- 20 sites surveyed

- Previously surveyed in 1999

- Previously supported diverse or abundant mussel populations

- Represent a range of stream size

Muckalee Ck

Kinchafoonee Ck

Chickasawhatchee Ck

Spring Ck

Results

Hydrologic and Geologic Classification

Fall Line Hills

Dougherty Plain

Fall Line Hills

Muckalee Ck

Kinchafoonee Ck

Chickasawhatchee Ck

Spring Ck

Mussel Abundance

Hydrologic Condition 2000

Per

cent

Cha

nge

-100

-80

-60

-40

-20

0

20

40

60

80

Flowing Stagnant or Dry

Changes in Mussel Abundance

1999 to 2001

Muckalee Ck

Kinchafoonee Ck

Chickasawhatchee Ck

Spring Ck

Conclusions

- Lower Flint tributaries were most sensitive to drying

- Freshwater mussels appear to require fresh water

-Greatest declines in mid-reaches of Flint tributaries (Dougherty Plain)

-Endangered, Threatened and Special Concern species still occur but are not abundant

- The best populations of mussels occur in the upper reaches of Kinchafoonee, Muckalee, and Chickasawhatchee Creeks

- Can these populations survive?

- Will other areas recover?

Future Outlook ?

Where are we now?Palmer Drought Index

1999 2010Year entering

“drought”Current

< -2< -2.5

Where are we now?Stream Flow

1999 2010

1000 cfs

1000 cfs

Year entering“drought”

Current

Where have we been?

Severe droughts

1953-1957

J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J

Pal

mer

Dro

ught

Sev

erity

Inde

x

-6

-4

-2

0

2

4

1998-2002

J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J

Pal

mer

Dro

ught

Sev

erity

Inde

x

-6

-4

-2

0

2

4

1998 1999 2000 2001 2002

1953 1954 1955 1956 1957

Where have we been?Comparison of historical droughts

1953-1954 1999-2000

Where have we been?

Flint River at AlbanyComparison of 1954 and 2000 drought flows(p=0.20)

Interval

1954-1955 1999-2000

Ave

rage

Mon

thly

Flo

w (

CF

S)

0

1000

2000

3000

4000

5000

6000

7000

8000

~ 3100~ 2500

Comparison of Drought Flows

Flint River at AlbanyComparison of 1954 and 2000 drought flows

Month

J F M A M J J A S O N D J F M A M J J A S

Ave

rage

Mon

thly

Flo

w (

CF

S)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

1954-1955 1999-2000

Comparison of Drought Flows

Flint River at Albany

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Med

ian

Mon

thly

Flo

w (

CF

S)

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

1939-1974 1975-2009

Historic Stream Flows

Conclusions – Lower FRB

- Current conditions appear comparable to those entering the “2000” drought

- 1954 drought more severe than 2000

- Lowest flows of record occurred during 2000

- Multi-year droughts cause progressively lower growing season flows (even following recharge)

- Stream flows are declining and may be reaching or exceeding critical levels during extended droughts.

“If the biota, in the course of eons, have built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the sign of an intelligent tinkerer.”

Aldo Leopold

Acknowledgements

Funding – R.W. Woodruff Foundation, J.W. Jones Center, Georgia EPD, and The Nature Conservancy

Field Assistance – R. Bambarger, M. Bell, B. Clayton, A. Liner, S. Kelly, L Bledsoe

Appendix Follows

Mussel Evolution and Life History

Freshwater Mussel Lure

Shiny-rayed Pocketbookminnow lure

Southern Pocketbook Lure

Fluted Kidney Shell Lure

Blackfly or midgeimitation

Freshwater Mussel Lures

- fish mistake lures for prey

- biting the lure releases glochidia

- glochidia infect gills or surfaces of the oral cavity

Historical Threats to Mussels

Pearl button industry

Pearl farming

Channel dredging

Historical Threats to Mussels

Non-point source pollution

Point source pollution

Reservoir construction

Historical Threats to Mussels

Zebra Mussels and distribution

Asiatic Clam

Endangered Species Act of 1973

“The Secretary shall, concurrently with a determination… that a species is an endangered species or a threatened species, designate any habitat of such species which is then considered to be critical habitat…” (ESA Section 4(a)(3)(A))

Critical Habitat Includes…

• Specific areas within or outside the geographical area occupied by the species when listed, on which are found those physical or biological features essential to the conservation of the species.

• Except in special circumstances, critical habitat does not include the entire geographical area which could be occupied by the species. (Paraphrased from: ESA Section 3(5)(A-C))

Critical habitat designations must be based on the best scientific information available, in an open public process, within specific time frames.

All federal agencies must ensure that any actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of a listed species, or destroy or adversely modify its designated critical habitat. A critical habitat designation does not set up a preserve or refuge, and applies only when federal funding, permits, or projects are involved. Critical habitat requirements do not apply to citizens engaged in activities on private land that do not involve a federal agency.

Implications of Critical Habitat Designation

2000 Drought Monitoring Study

- 9 sites stratified by stream size- 3-5 4 m2 quadrats per site- Weekly monitoring of

mussels depth bottom velocity DO

- Continuous temperature measurements

Status of Mussels 1999 to 2001Common Species

Elliptio complanata

Elliptio crassidens

Toxolasma paulus

Uniomerus carolinianusVillosa lienosa

Villosa vibex

1999 (#/site) 2001 (#/site)

Flowing 226 314 p=0.02

Non-Flowing 181 71 p=0.01

Status of Mussels 1999 to 2001Endangered Species

Shiny-rayed PocketbookSites 11/7

Total 131/56 Gulf MoccasinshellSites 2/1

Total 9/17

Oval PigtoeSites 5/6

Total 42/87

Status of Mussels 1999 to 2001Special Concern Species

Inflated SpikeSites 10/8

Total 99/161 Southern FatmucketSites 9/1

Total 20/8

Sculptured PigtoeSites 14/11

Total 360/543

Southern CreekmusselSites 4/5

Total 10/9

Downy RainbowSites 3/1

Total 31/1

Where are we now?U.S. Drought

1999 2010