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● Low alkalinity● Very soft

Site 3

Research Site 4:

● Oligotrophic● Low alkalinity● Very soft Site 4

Research Sites:

Site 3 and 4

Site 3 and 4

Site 2

Site 1

Site 1 and 2

Site 1 Site 3Site 2

Num

ber o

f Toa

ds

Site Number

Toad size and population by site:● T-test, size: site 1 and 2 p = 0.0886

Site

Num

ber o

f toa

ds a

nd T

oad

Size

*

Total Dissolved Solids (ppm)

Num

ber o

f toa

ds

TDS:● Positive correlation

pH:

pH

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

Number of toads

Hardness:● Strong positive correlation

Hardness (ppm)

Num

ber o

f toa

ds

Number of toads

Size

of p

ond

(cub

ic m

eter

s)

Size of pond:- Positive correlation- Number of toads per cubic meter are somewhat proportional

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?

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 (m3): 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

Site 1 Site 2 Site 3 Site 4