In class, you described a population of a single species, the ornate chorus frog. Sometimes
biologists group multiple species together to describe a population of a more general group of
animals. In this exercise, you will read about a unique group of animals that only breed in
ponds that hold water temporarily: ephemeral pond-breeding amphibians. These amphibians
spend the majority of their lives in the uplands. The quality of the upland habitat is therefore
just as important as the quality of the wetland habitat. For your assignment, you will describe
and compare the populations of ephemeral pond-breeding amphibians in native longleaf pine
habitat versus a sand pine plantation (details in the Your Assignment section).
The following article is based on real research projects and data collected by the Coastal Plains
Institute (a nonprofit organization based in Tallahassee, FL). Some of the data were reported in
Means (2007), Means and Means (1998), Means and Means (2005). The rest of the data remain
unpublished. The data presented in Tables 1 and 2 are loosely based on this published and
unpublished data.
Ephemeral Pond-Breeding Amphibians of the Munson Sand Hills, Florida
An article written for CPALMS by Rebecca Means
(Remote Footprints and Coastal Plains Institute)
Just south of the Florida state capital city of Tallahassee, lies the rare and extremely
diverse longleaf pine sandhill community called the Munson Sand Hills. These sandhills
are a fire-maintained community rich with diverse plants, insects, birds, reptiles,
amphibians, and mammals. Many rare and threatened species inhabit this region
including the red-cockaded woodpecker, indigo snake, black bear, gopher tortoise, and
gopher frog.
Unfortunately, many acres of the Munson Sand Hills were converted to a sand pine
plantation in the mid-1900’s. Intensive forestry practices, like pine plantations, can
remove native groundcover like grasses and other vegetation, alter topography and
hydrology, shade-out herbaceous vegetation within wetlands, and reduce the
biodiversity of an area. This article briefly describes research conducted by Coastal
Plains Institute to sample ephemeral pond amphibian populations in the Munson Sand
Hills.
Ephemeral wetlands are isolated, usually small, ponds with a cyclic nature of drying and
refilling (picture at left). Termed “hydroperiod,” the
duration an ephemeral pond holds water can vary from a
few weeks to a year or two. Hydroperiod often
varies from year to year and pond to pond. From an
amphibian perspective, the cyclical nature of pond filling
and drying is significant because it creates an
inhospitable environment for many species of
predacious fish and macroinvertebrates. A suite of
amphibian species that lack the defenses to co-exist with
these predators require ephemeral ponds for breeding habitat. Therefore, ephemeral
ponds support a different assemblage of species than do more permanent waters.
In the Munson Sand Hills, ephemeral ponds are essential to the survival of two
imperiled amphibians – the striped newt and the gopher frog (pictured below at right).
Other amphibians also depend on these wetland including mole salamanders (pictured
below at center), barking treefrogs (pictured below at left), pine woods treefrogs, little
grass frogs, ornate chorus frogs, southern chorus frogs, and oak toads.
Twice a year over a four year period, biologists with Coastal Plains Institute sampled
245 ponds in the Munson Sand Hills using seines and dipnets. Some of the ponds (65%)
were located on the Apalachicola National Forest, an area with a native longleaf pine
savanna community. The other ponds (35%), were surrounded by intensively managed
sand pine plantation. Was there a difference in the ephemeral pond-breeding
amphibian populations found in native longleaf pine savanna versus sand pine
plantation?
References
Means, D. B. 2007. Life cycles, dispersal, and critical habitat utilization of
vertebrates dependent upon small isolated water bodies in the Munson Sandhills and
Woodville Karst Plain, Leon County, Florida. Final Report to the Department of
Transportation for OMNI Project 010562. 69 pages.
Means, D. B. and R. C. Means. 1998. Distribution of the striped newt
(Notophthalmus perstriatus) and gopher frog (Rana capito) in the Munson Sand Hills
of the Florida panhandle. Final report to the U. S. Fish and Wildlife Service, Jackson,
MS, for Order No. 43910-5-0077.
Means, D. B. and R. C. Means. 2005. Effects of sand pine silviculture on pond-breeding
amphibians in the Woodville Karst Plain of north Florida. Pages 56-61 in W. Meshaka
and K. Babbitt, eds. Status and conservation of Florida amphibians and reptiles. Florida
University Presses, Gainesville, Florida.
Your Assignment
Fill out the tables on the next page to obtain information about ephemeral pondbreeding amphibian populations in two different habitats. Use the characteristics of a
population you learned in class to compare the two different populations in the Munson
Sand Hills. Write a two page paper that describes each population (longleaf pine
savanna and sand pine plantation) then use the observations to make inferences about
the population. You may choose to use the observations to make inferences about
individual species, the ephemeral-pond breeding amphibian population as a whole, or
both. Be sure to describe your inferences based on the observations and any factors that
may strengthen or potentially invalidate your inferences. For example, did you infer
anything from the fact that only adults were encountered for several species in the sand
pine plantation habitat? Would knowing that the tadpoles of these species depend on
herbaceous vegetation to hide from predators strengthen your inference?
Be sure to attach your completed tables (Page 3 and 4) with your paper.
Hint: Remember populations can be described at different scales. Our in-class example
looked at population density in terms of # of individuals/pond area (m2). In this
exercise you will need to calculate density in terms of number of individuals/pond or
average number of individuals/pond.
Table 1. An Example of Amphibian Population Data Collected During Surveys in the Munson Sand Hills – Longleaf Pine
Savanna Habitat. A total of 160 ponds were sampled.
Species
Percentage
of Ponds
Detected
Small
Larvae
(< mm)
Eggs
Large
Larvae
(> mm)
Total
Number of
Individuals
Adults
Male
Female
Mole salamander
25%
0
953
501
800
754
Striped newt
18%
0
1,216
1,200
451
398
Barking treefrog
45%
28,754
2,555
3,450
620
632
Ornate chorus frog
42%
23,522
1,780
880
223
265
Southern chorus frog
53%
15,420
2,420
3,001
599
606
Gopher frog
26%
12,250
42
804
201
255
Averages
Totals
(eggs, larvae,
and adults)
Density
(Average
number of
individuals per
wetland)
Table 2. An Example of Amphibian Population Data Collected During Surveys in the Munson Sand Hills – Sand Pine
Plantation Habitat. A total of 85 ponds were sampled.
Species
Mole salamander
Percentage
of Ponds
Detected
Small
Larvae
(< mm)
Eggs
Adults
Large
Larvae
(> mm)
Male
Female
13%
0
0
1
15
18
Striped newt
0%
0
0
0
0
0
Barking treefrog
2%
0
0
0
1
3
17%
0
0
20
8
8
Southern chorus frog
8%
0
0
0
20
23
Gopher frog
1%
0
0
0
0
1
Ornate chorus frog
Averages
Totals
Total Number of
Individuals (eggs,
larvae, and adults)
Density
(Average number
of individuals per
wetland)
Grading Rubric
Describing a Two Populations of Ephemeral Pond-Breeding Amphibians Rubric
Below Standard (1
Approaching
Above Standard (4
At Standard (3 pts)
pt)
Standard (2 pts)
pts)
Learning Objective
Frequent errors in
Few errors in spelling or No errors in spelling or
Many errors in spelling
spelling and grammar
grammar. Writing is
grammar. Writing is
or grammar. Writing is
Mechanics of Writing
distract the reader.
cohesive and organized.
very cohesive and well
disorganized. Main
Writing lacks strong
Main points are
organized. Main points
points are not described.
organization.
described.
are clearly described.
Characteristics of a
Population (includes
number of individuals,
age structure, density,
distribution)
Little or no description
of population
characteristics is
included. Student fails
to demonstrate an
understanding of how to
describe a population.
Several population
characteristics are
missing or student
describes only one
thoroughly. Student
demonstrates a minimal
understanding of how to
describe a population.
A few population
characteristics are
included for each
population. Student
demonstrates a basic
understanding of
population structure.
All population
characteristics are
included for both
populations. Student
demonstrates a thorough
understanding
population structure.
Comparison
No comparison between
the two populations is
included. No population
characteristic vocabulary
is used.
Very little comparison is
made between the two
populations. Few
population
characteristics
vocabulary words are
used.
Comparisons between
the two populations are
made and some
population characteristic
vocabulary words are
used.
Comparisons between
the two populations are
thoroughly described
using appropriate new
vocabulary words.
Three inferences about
the population are made
and are described.
Descriptions reflect a
basic understanding of
of observation and
inference.
More than three
inferences about the
populations are made
and are described
thoroughly.
Descriptions reflect a
complete and thorough
understanding of the
relationship between
observation and
inference.
Observation/Inference
No inferences about the
two populations are
made.
One or two inferences
about the population are
made but are not
described thoroughly.