Introduction: Toads are in decline Humans have a massive impact - - PowerPoint PPT Presentation

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Introduction: Toads are in decline Humans have a massive impact - - PowerPoint PPT Presentation

Feb 25, 2023 220 likes •441 views

How does water quality affect toad populations? Finn Amster, Hari Kumar, and Matt Halper Introduction: Toads are in decline Humans have a massive impact on toad habitats Both terrestrial and aquatic California toad ( Anaxyrus

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How does water quality affect toad populations?

Finn Amster, Hari Kumar, and Matt Halper

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Introduction:

  • Toads are in decline
  • Humans have a massive impact on toad habitats

○ Both terrestrial and aquatic

  • California toad (Anaxyrus boreas halophilus):

○ Lay eggs at high elevations ○ Need open water for breeding ○ Stripe down the middle of the back

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Hypotheses:

Toad populations will be higher if

  • The temperature is higher
  • Nutrient concentration is high
  • pH is neutral
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Procedure:

  • Pick 4 test sites
  • Test water quality
  • Measure area and depth of body of water
  • Catch toads over 15 minutes
  • Count, measure, and release
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Research Site 1:

  • Eutrophic
  • Low alkalinity
  • Soft

Site 1

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Research Site 2:

  • Eutrophic
  • Low alkalinity
  • Soft

Site 2

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Research Site 3:

  • Oligotrophic
  • Low alkalinity
  • Very soft

Site 3

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Research Site 4:

  • Oligotrophic
  • Low alkalinity
  • Very soft

Site 4

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Research Sites:

Site 3 and 4 Site 3 and 4 Site 2 Site 1 Site 1 and 2

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Site 1 Site 3 Site 2

Number of Toads Site Number

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Toad size and population by site:

  • T-test, size: site 1 and 2 p = 0.0886

Site Number of toads and Toad Size

*

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Total Dissolved Solids (ppm) Number of toads

TDS:

  • Positive correlation
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pH:

pH

  • Strong positive correlation
  • Unexpected but probably due to natural geographical water pH
  • Water tends to be around 8

Number of toads

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Hardness:

  • Strong positive correlation

Hardness (ppm) Number of toads

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Number of toads Size of pond (cubic meters)

Size of pond:

  • Positive correlation
  • Number of toads per cubic meter are somewhat proportional
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Discussion:

Main trends

  • pH
  • Pool size
  • Hardness
  • TDS
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Hypotheses: Revisited

Toad populations will be higher if

  • The temperature is higher
  • Nutrient concentration is high
  • pH is neutral
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How do Humans Relate to Toads and their Survival?

  • Human waste greatly affects water sources

○ Runoff from sewage, fertilizers, industrial manufacturing, etc.

  • Small changes in ponds have big impact on toad

populations

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Going Forward:

Improvements and Sources of Error:

  • More data points
  • Test temperature throughout the day

Further Questions:

  • Cause of elevated pH in Tahoe
  • Specific human activity impacting toads
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Questions?

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Water Temp (°C): 9.7 12.8 16 14.5 Air Temp (°C): 24.2 24.2 24.2 24.2 pH: 8.4 8 7.7 7.6 TDS (ppm): 182 183 29 30 Turbidity (cm): 122 122 122 72 Nitrite (ppm): 0.5 0.5 Size of Pond (m3): 123.5 19.8 15.8 1.6 Alkalinity (ppm): 1.5 2 7 4.8 Hardness (ppm): 100 50 Depth (m): 65.2 17.6 39.3 16.5 Number of Toads: 17 7 1

  • Avg. Size (cm):

2.1 1.8 11.5 Site 1 Site 2 Site 3 Site 4