Transcript Population Analysis of Bull Frogs and Green Frogs in Lake Romeyn.

Analysis of the Co-Existence the of
Bullfrog and Green Frog in Lake
Romeyn According to Microhabitats.
By Ben Ames, Chloe Fross, and Ross Julian
S
Bullfrog (Rana catesbeiana)
(ADW, 2011)
Bullfrog (Rana catesbeiana)
Habitat Selection
S Found on the edges of large bodies of water with grasses
(DeGraaf 2001).
S Have been found in areas with significant human
disturbance (increase in water temperature or aquatic
vegetation) (Bruening, S. 2002).
Bullfrog Food Habits
S Small prey include fish, other frogs, salamanders, newts,
young turtles, snakes, small birds, mice, crayfish, insects,
snails, and spiders (DeGraaf 2001).
S Hunt for prey in water weeds (DeGraaf, 2001).
S Tadpoles are mainly vegetarian, but they can eat dead
animals, usually fish (DeGraaf, 2001).
Bullfrog Breeding
S Breeds successfully in deep water (DeGraaf 2001).
S Known to breed in shrub-sheltered areas (DeGraaf 2001).
S Breeds from late May to July (DeGraaf 2001).
S 12,000 to 20,000 eggs are laid in a mass (DeGraaf 2001).
Green Frog ( Rana clamitans melanota)
(ADW, 2011)
Green Frog (Rana clamitans melanota)
Habitat Selection
S Known to inhabit the edges of a variety of aquatic habitats
(DeGraaf 2001).
S Including the edges of lakes, ponds, creeks, woodland
streams, lime-stone quarry pools, springs, vernal pools,
moist woodlands near water, fens, bogs, tidal creeks, and
mill ponds (DeGraaf 2001).
Green Frog Food Habits
S The Green Frog hunts for prey in vegetation near the shore
(DeGraaf 2001).
S Prey include insects and their larvae, worms, small fish,
crayfish and other crustaceans, newts, spiders, small frogs,
and mollusks (DeGraaf, 2001).
S 60 percent of their food is comprised of beetles, flies,
grasshoppers, and caterpillars (DeGraaf 2001).
Green Frog Breeding
S Eggs are deposited in floating masses of jelly attached to
underwater twigs and stems in permanent water (DeGraaf
2001).
S Breed from April to August; hibernation ends in early spring
and breeding begins in May (DeGraaf 2001).
Competition between the
Bullfrog and the Green Frog
S There is evidence of strong competition between the two
species, with bullfrog tadpoles tending to be the superior
competitor because of their higher level of feeding activity
(Kentwood D. Wells, 2007).
S The competition between the species is influenced by
predation (Kentwood D. Wells, 2007).
Competition between the
Bullfrog and the Green Frog
S Bullfrogs are observed to be the greater competitor of the
two species, but for in ponds without fish, because the
bullfrog is less likely to a source of prey to the fish and the
presence of fish decreases bullfrog predators (Kentwood D.
Wells, 2007).
S The competition between the Green Frog and the Bullfrog
reduces the growth rates of tadpoles (Kentwood D. Wells,
2007).
Research Question
S How do the Green Frog and Bullfrog coexist in the Lake
Romeyn habitat?
Hypothesis
S The Green Frog and Bullfrog are able to coexist as
competing species in Lake Romeyn because of the different
use of various microhabitats.
Materials
S Minnow traps
S Buckets for Counting
S Flags for trap identification
S Boots
Methods
S We set 18 minnow traps in groups of 4-6 in the Lake Romeyn
Habitat.
S We went out each day for 45 minutes to check the trap data.
S We recorded the number of Green Frog and Bullfrog Tadpoles in
each trap.
S We looked for patterns or distinctions between the microhabitats
where the Green Frogs and Bullfrogs were found.
S Our site qualifications were based on depth, amount of vegetation
and a scale of sediment on the pond’s floor.
Methods 2 (Variables)
S Site 1 (plots 1-4): large amount of organic sediment, grasses,
medium depth
S Site 2 (plots 5-8): small amount of organic sediment, little to no
vegetation in the water, very deep-some traps fully submerged
S Site 3 (plots 9-12): moderate amount of organic sediment, grasses,
medium depth
S Site 4 (plots 13-18): moderate amount of organic sediment, little
to no vegetation, medium depth
Pictures From the Field
S
Site 1
Site 2
Site 3
Site 4
Results and Analysis
S
Results
Table 1: The Bullfrog and Green Frog data recorded with empty traps omitted
Date
Time
Site
Bullfrog
Green Frog
5/13/11
2:10 PM
1
1
0
5/13/11
2:10 PM
2
1
1
5/14/11
11:30 AM
1
0
1
5/16/11
1:00 PM
4
0
1
5/19/11
6:00 PM
3
0
2
5/22/11
8:00 PM
3
1
0
5/22/11
8:00 PM
4
1
1
5/23/11
1:05 PM
4
2
0
5/24/11
9:00 AM
4
3
0
Results and Analysis 1
Table 1: The Bullfrog and Green Frog data
recorded with empty traps omitted
Date
Time
Site
Bullfrog
Green Frog
5/13/11
2:10 PM
1
1
0
5/13/11
2:10 PM
2
1
1
5/14/11
11:30 AM
1
0
1
5/16/11
1:00 PM
4
0
1
5/19/11
6:00 PM
3
0
2
5/22/11
8:00 PM
3
1
0
5/22/11
8:00 PM
4
1
1
5/23/11
1:05 PM
4
2
0
5/24/11
9:00 AM
4
3
0
S
Figure 1 shows that both species of
tadpole were found in all four sites
with varying abundance, but only
on seven days of the two week
period when data was collected.
S
According to our data we could
find no strong correlations
between favorable microhabitats
for each species.
Analysis of Figure 1
S
Figure 1 shows the number of tadpoles of
each species found on each site.
S
Site 1 had an equal number of bullfrog and
green frog tadpoles.
S
Site 2 and 3 each had 2 green frog tadpoles
and 1 bullfrog tadpole, which is not a large
enough amount of data to show a
conclusive trend.
Site 4 was the only site with a significantly
larger number of one species versus the
other.
S There were 6 bullfrog and 1 green frog
tadpoles
S Characteristics: moderate amount of
organic sediment, no vegetation,
medium depth
7
6
5
4
Bullfrog
Green Frog
3
S
2
1
0
Site 1
Site 2
Site 3
Site 4
Figure 1: The Bullfrog and Green Frog Tadpoles
Found on Each Site to Help Present a Preference
of Microhabitats
Figure 1
7
6
5
4
Bullfrog
Green Frog
3
2
1
0
Site 1
Site 2
Site 3
Site 4
Figure 1: The Bullfrog and Green Frog Tadpoles Found on Each Site to
Help Present a Preference of Microhabitats
Discussion and Conclusions
S Our data was too scarce to draw conclusions of our hypothesis that
the microhabitats would allow for the co-existence of the bullfrog and
the green frog in Lake Romeyn.
S The weather may have been a factor in the presence of bullfrog and
green frog’s breeding and developmental activity which would
decrease the number of each species in Lake Romeyn.
S The temperatures during the two week data collection period were
mostly around 50 degrees Fahrenheit, with two days reaching 60
degrees Fahrenheit, and of those days most were rainy causing a
decrease in water temperature.
S
Although on two days the temperature reached 60, the water is a buffer
and does not allow the temperature to be altered by one or two days of
warm weather (which were not consecutive).
Error and Bias
S The weather’s impact on the data collected suggests that in
the a future study must be altered by choosing different
variables to measure to explain the co-existence between
bullfrogs and green frogs other then microhabitats (for
example food resources or an introduction of predation,
which would require an indoor lab).
S Or…one would have to start the lab later in the year
Literature Cited
S
Degraaf, Richard M and Yamasaki, Mariko. 2001. New England Wildlife: Habitat, Natural History and
Distribution. University Press of New England.
S
Bruening, S. 2002. The Bullfrog "Rana catesbeiana”, Animal Diversity Web.
http://animaldiversity.ummz.umich.edu/site/accounts/information/Rana_catesbeiana.html.
Accessed May 01, 2011
S
Wells, Kentwood D. 2007. The Ecology and Behavior of Amphibians. Chicago. The University of Chicago
Press.
http://books.google.com/books?id=eDKEKy5JJbIC&pg=PA779&lpg=PA779&dq=competition+between+th
e+green+frog+and+the+bull+frog&source=bl&ots=EtE1LARTyw&sig=vcp7d2lAyZ0fSI9xrfwtTS2D2QQ&h
l=en&ei=hSW-TcfKGs2gtwfKPXdBQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBgQ6AEwAA#v=onepage&q=competition%
20between%20the%20green%20frog%20and%20the%20bull%20frog&f=false
Accessed May 1, 2011.
S
Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2006. The Animal Diversity
Web. http://animaldiversity.org.
Accessed May 26, 2011