Herp Meeting 2010 Tn


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Surasinghe, T. D., and Baldwin, R. F. (2010). The ecological responses of stream salamanders to land use activities in the watershed areas in Piedmont and Blue Ridge ecoregions, USA: An ongoing project. Sixteenth Annual Tennessee Herpetology Conference, Cumberland Plateau Wildlife Management Area, TN.

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Herp Meeting 2010 Tn

  1. 1. Ecological Responses of Stream Salamanders to Land-use in the Piedmont and Blue Ridge: Overview and Methods Thilina Surasinghe & Robert Baldwin Dept of Forestry and Natural Resources Clemson University, Clemson, SC
  2. 2. Global Biodiversity Loss Causes : habitat loss, overexploitation, pollution, invasions, pathogens, climate change. Anthropogenic drivers: land transformation  Agricultural expansion, urbanization, infrastructure development, river impoundments, international trade, increasing demand for natural products Ecological cascades and keystone functions
  3. 3. Species Distribution • Landform diversity • Habitat heterogeneity • Physiography • Hydrology • Microhabitat features • Resource availability• Disturbance regimes!!!!!• Land-use !!!!!!• Habitat modification!!!!!• Community interactions!!!!
  4. 4. Stream salamanders as focal species• Environmental sentinels• Disturbance intolerance???• Plethodontids & the Wilder –Dunn Hypothesis• Major form of biomass in headwater streams • Role in nutrient cycles and transportation • Role played in trophic cacades • Dependency on stream- riparian/watershed interactions
  5. 5. Threats and conservation of amphibians • Massive population declines – 32% Redlisted globally • Impacts of land development & anthropocentric land-use practices – Altered stream morphology & hydrology – Disturbances in the watershed and riparian areas – Degradation in water quality – Biotic homogenization
  6. 6. Study Area – Upstate South Carolina• Southern Appalachian Mountains and Southern United States• Rich in biodiversity & endemism Kevin Kubach
  7. 7. Study Area – Upstate South Carolina• Level III EPA ecoregion: Blue Ridge & Piedmont• Four major river basins: Savannah, Saluda, Catawba, Broad
  8. 8. Study Area – Upstate South Carolina • High rate of land development, urbanization, population growth • Intensive land use history • Pressure on native biodiversity!!!
  9. 9. Project Objectives• How different land-use activities in the riparian zone and the watershed affect the habitat association of stream-dwelling salamanders?• Does historical alterations in the natural habitats affect the current distribution and habitat occupancy of stream salamanders?• Does anthropogenic land-use practices alter community interactions (competition) among stream salamanders?
  10. 10. Methods & Materials• Randomized block design – Blocked across level IV ecoregions & river basins – 40 sampling locations – land-use types: forested areas, agricultural lands, residential areas, & urban areas• Field transect survey – Stream transects in the wetted channel (100 m) – Riparian belt transects (100 m x 5 m) – Visual observation & active searching – Random sampling : sequence/time among different sites
  11. 11. Active Searching• Stream transects – Diurnally searching all stream channel habitats with rectangle-framed kick nets, D-framed nets and dip nets• Belt transects – Nocturnally searching all riparian microhabitats• Date, starting /ending time, weather & the crew size are recorded• Will be surveyed for two consecutive years (April – July)• Identification and specimen preservation
  12. 12. Methodology: Determining Habitat Association• Nested analysis to determine the effects of – Different land-use activities in the riparian areas – Different habitats variables in the sampling location on species composition of stream salamanders – Metrics: Relative nestedness and discrepancy measure• Categorization of species assemblages reflecting species response to land-use gradient – Disturbance exploiters, disturbance adapters, disturbance avoiders – Ordination (NMDS)
  13. 13. Methodology: Determining Habitat Association• 12 habitat variables will be recorded along transects – To indicate land development, disturbance, & ecological conditions of the sampling locations – A correlation test to determine correlation between habitat variables and species occurrence
  14. 14. Methodology: Effects of Historical Land-use 1944 2010• Comparison of historical aerial photos (1920-60) with LULC 2001• Spatial scale: 200 m, 500 m, 1000 m–radius from sampling points• Calculate proportional coverage for the four land-use types• Use historical land-use cover as a variable for the correlation
  15. 15. Methodology: Community Interactions Vs• Four riparian land-use types simulated in artificial streams• Experimental species: Urban adapter Vs Urban avoider• Coexistence and isolation• Observations/measurements: body weight, snout-vent length, spatial occupancy, # individuals alive• Assess: (i) percentage survival; (ii) percentage body weight change; (iii) percent change in body length; (iv) growth rate; (v) daily movement range
  16. 16. Acknowledgement:Dr Mark Scott & Stream Bioassessment team, SC DNRDr John Hains, Dr Hap Wheeler, Dept of Biological SciencesDr Bryan Brown, Dept of Forestry & Natural ResourcesHighlands Biological Station, NC