Slide 1: Streams make lousy melting pots
(Gene Helfman, University of Georgia)
Slide 2: THEMES:
• S. E. RIVERS ARE SPECTACULARLY DIVERSE; LOTS OF ENDEMICS
• LAND USE AFFECTS FISHES, NOT NECESSARILY AS EXPECTED
• HABITAT MODIFICATION PRECEDES INVASION, ALIEN OR OTHERWISE
• DIVERSITY IS NOT NECESSARILY GOOD, HOMOGENIZATION IS BAD
• ECOSYSTEM-BASED MANAGEMENT IS ESSENTIAL
Slide 3: Land use effects collaborators
Fred Benfield (VPI)
Paul Bolstad (U. Minn.)
Jo DeVivo
Ned Gardiner
Jon Harding (Cawthron Inst, NZ)
Josh Harper (REU)
Chris Jeffrey
Ethelbert Barksdale Jones III
Judy Meyer
Mike Paul
Heather Reed (REU)
Paula Marcinek (REU)
*Mark Scott*
*Allison Vogt*
Slide 4: Photo
Slide 5: Map
Slide 6: Photo
Slide 7: FRESHWATER FISH DIVERSITY: THE BIG PICTURE
LOCALE NO. OF SPECIES
GLOBAL 9000+
Temperate 1750
Europe, Asia, Oz/NZ 775
North America 950
U.S. 790
The Southeast! 560 (+50)=80%
(bugs, too!)
Slide 8: Chart
Slide 9: “. . . the species are different, each river having its own kinds, with the nearest relatives occurring in the next stream.” David Starr Jordan, 1878
Endemism in ecosystems, especially in the uplands!
Slide 10: Stream habitats and corresponding fish species
Riffle: Darters and sculpins
Run: Large suckers, trouts, (spawning minnows!)
Pool: Minnows! Madtoms, sunfish
Wetland: Pygmy sunfish, topminnows (spawning darters, juveniles!)
Slide 11: DARTERS! (150+ spp) (photos of darters)
Slide 12: MINNOWS! (230+ spp) (photos of minnows)
Slide 13: Photos
Slide 14: THE POINT HERE IS
S.E. rivers have high diversity and endemism, especially among upland, low productivity, cool/clear water, riffle adapted species
Slide 15: Two major causes of declining diversity among freshwater fishes:
1. Habitat destruction
2. Introduced species
(Slide 16: blank)
Slide 17: Ag/urbanization, deforestation, impervious surfaces, riparian loss
in “upland” streams
Slide 18: Which fishes are imperiled?
25% of benthic fishes are imperiled; only 9% of non-benthic fishes are imperiled
Slide 19: The relationship between benthic habits and vulnerability in stream fishes:
• It happens
• It rolls downhill
• It sinks
Slide 20: Andrew’s work (Spotfin chub photos and charts)
Slide 21: Cartoon: “Well, thank God we all made it out in time. …’Course now we’re equally screwed.”
Slide 22: Two major causes of declining diversity among freshwater fishes
1. Habitat destruction
2. Introduced species
Slide 23: Cartoon
Slide 24: Photo of trout, and chart. “A good rule of angling philosophy is not to interfere with any fisherman’s ways of being happy, unless you want to be hated.” Zane Grey 1919, Tales of Fishes
Slide 25: Photos of catfish.
Slide 26: Photo of eucalyptus grove
Slide 27: Photo collage of non native species
Slide 28: Quotes on homogenization of fauna.
Slide 29: How faunas became homogenized.
Slide 30: blank
Slide 31: Land use comparisons, 1950 & 1990, French Broad watersheds
Little Tennessee River riffles chart
Slide 32: Chart: Little Tennessee River riffles
Slide 33: Chart: Abundance vs land use and stream size
Slide 34: Chart: Diversity relative to land use and stream size
Slide 35: List of endemic highlands fishes and widespread N American fishes of the S. Appalachians
Slide 36: Map of Green darter distribution and photo of fish.
Slide 37: Maps of Blue gill distribution and photo of fish.
Slide 38: blank
Slide 39: Highland endemics, Lowland invaders, and Land use charts and phtoo of fish
Slide 40: Chart of Cosmopolitan Invasion. The endemic: widespread ratio.
Slide 41: Chart of time Time Course of Homogenization
Slide 42: How faunas became homogenized
Detecting ongoing homogenization requires looking at the actual species involved, not just measuring diversity.
Slide 43: Land disturbance homogenizes stream habitats (via sedimentation), facilitating the invasion of generalists that eventually replace endemic specialists,
resulting in faunal homogenization.
Slide 44: Fishes (etc) live in streams
Streams sit in the landscape
To protect the fishes (and other organisms)
You have to regard the entire landscape.
Thus: ecosystem-based management
Slide 45: Photo
Slide 46: Photo
Slide 47: Photo
Slide 48: Photo