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 boreas halophilus) : ● Lay eggs at high elevations ○ Need open water for breeding ○ Stripe down the middle of the back ○
Hypotheses: Toad populations will be higher if The temperature is higher ● Nutrient concentration is high ● pH is neutral ●
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 ●
Research Site 1: Eutrophic ● Low alkalinity ● Soft ● Site 1
Research Site 2: Eutrophic ● Low alkalinity ● Soft ● Site 2
Research Site 3: Oligotrophic ● Site 3 Low alkalinity ● Very soft ●
Research Site 4: Oligotrophic ● Low alkalinity ● Very soft ● Site 4
Research Sites: Site 1 and 2 Site 3 and 4 Site 1 Site 2 Site 3 and 4
Number of Toads Site Number Site 2 Site 1 Site 3
Toad size and population by site: T-test, size: site 1 and 2 p = 0.0886 ● Number of toads and Toad Size * Site
TDS: ● Positive correlation Number of toads Total Dissolved Solids (ppm)
pH: ● Strong positive correlation ● Unexpected but probably due to natural geographical water pH ● Water tends to be around 8 pH Number of toads
Hardness: ● Strong positive correlation Number of toads Hardness (ppm)
Size of pond: - Positive correlation - Number of toads per cubic meter are somewhat proportional Size of pond (cubic meters) Number of toads
Discussion: Main trends pH ● Pool size ● Hardness ● TDS ●
Hypotheses: Revisited Toad populations will be higher if The temperature is higher ● Nutrient concentration is high ● pH is neutral ●
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
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 ●
Questions?
Site 1 Site 2 Site 3 Site 4 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 0 0 Size of Pond (m 3 ): 123.5 19.8 15.8 1.6 Alkalinity (ppm): 1.5 2 7 4.8 Hardness (ppm): 100 50 0 0 Depth (m): 65.2 17.6 39.3 16.5 Number of Toads: 17 7 1 0 Avg. Size (cm): 2.1 1.8 11.5 0
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