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Stream crayfish in Mississippi: who's where and why

Stream crayfish in Mississippi: who's where and why. Susan B. Adams Melvin L. Warren, Jr. USDA Forest Service, Southern Research Station Center for Bottomland Hardwoods Research, Oxford, MS Presented to: Alabama Fisheries Assoc, Feb. 22-24, Orange Beach, AL. METHODS.

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Stream crayfish in Mississippi: who's where and why

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  1. Stream crayfish in Mississippi: who's where and why Susan B. Adams Melvin L. Warren, Jr. USDA Forest Service, Southern Research Station Center for Bottomland Hardwoods Research, Oxford, MS Presented to: Alabama Fisheries Assoc, Feb. 22-24, Orange Beach, AL

  2. METHODS

  3. Holly Springs NF sites 1999-2000 Oxford Km

  4. Habitat 20-30 times mean width • Transect endpoints • width, bank height, bank veg • Points along transect • depth, current, % canopy, substrate, • +/- of wood, detritus, and aquatic veg. • Watershed area

  5. RESULTS

  6. Crayfish diversity 1,200 specimens of at least 9 species Orconectes chickasawae Procambarus vioscai Procambarus ouachitae Procambarus hayi Procambarus acutus Cambarus diogenes

  7. Co-occurrence analysis • Significant structuring of crayfish assemblages • Co-occurrence C = 8.9, P-value = 0.049 • Checkerboard score = 20 , P-value = 0.319 • Species combinations = 21, P-value = 0.01

  8. PCA plot of sample sites in species space P. ouachitae P. hayi O. chickasawae O. etnieri P. vioscai

  9. P. ouachitae P. vioscai

  10. Crayfish and reach-scale habitat • PCA and Mantel tests • Crayfish density related only to stream size variables (not to wood, veg, substrate, canopy)

  11. Crayfish and reach-scale habitat • PCA and Mantel tests • Crayfish density related only to stream size variables • Correlations: density by sp. vs. stream size • Most species, r < 0 • P. vioscai, P. ouachitae no sig. correlation • P. hayi r < 0 with area but not depth

  12. Crayfish and reach-scale habitat • PCA and Mantel tests • Crayfish density related only to stream size variables • Correlations: density vs. stream size • Most spp. r < 0 • P. vioscai, P. ouachitae no sig. correlations • P. hayi r < 0 with area but not depth • Species-area relationship negative!

  13. POSSIBLE EXPLANATIONS

  14. Catfish predation experiment

  15. Experimental design - 2 trials - 3 weeks each - Count survivors nearly daily

  16. Results – trial one • Catfish predation low on large P. hayi. • Catfish will jump out of tanks!

  17. Results – trial 1 Control – no shelter Control - shelter Catfish - shelter Catfish – no shelter

  18. Results – trial 2

  19. THANKS TO: Dr. Chris Taylor, INHS Mr. Gordon McWhirter Ms. Amy Commens Dr. Wendell Haag Mr. Clifford Harwell Ms. Gayle Henderson Ms. Leann Staton Ms. Rebecca Reekston & the many students who worked so hard! Funded by: National Forests of Mississippi & the USFS Southern Research Station

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