Risk Assessment
Species Data Matrices: biological attributes that may
contribute to vulnerability. Version 1.0
In 2000, the Northeast regional working group of Partners in Amphibian and Reptile
Conservation (NEPARC) began work to assess factors contributing to the risk or potential
vulnerability of Northeast amphibians and reptiles. This website serves as a repository for the information assembled.
Table of contents
Introduction
Limitations
Knowledge Gaps
Anura (frogs and toads)
Caudata (salamanaders and newts)
Squamata (snakes and lizards)
Testudines (sea and freshwater turtles)
Question List (pdf file)
Data Matrices and Bibliographies
Acknowledgements
This project began a process to assess factors contributing to the risk or potential
vulnerability of Northeast amphibians and reptiles. The first step was to examine their
biological attributes. A set of 38 questions (pdf file) was developed
and organized into the following categories where vulnerabilities may exist:
- Global Rank: global conservation status (as
obtained from the Nature Conservancy's NatureServe Conservation
Status Ranking data)
- Habitat: habitat requirements and the affect
of introduced species
- Life History and Demographic Traits: characteristics
pertaining to reproduction, growth, and survival, including collection
pressures
- Movement and Habitat Use: juvenile dispersal,
adult movement, and population distribution throughout habitat
and geographic range
- Miscellaneous: do humans consider the species
to be a threat due to toxic secretions/venom?
With these questions, a data matrix was created with herpetofaunal species (common and
scientific names provided) making up the rows and the question topics making up the columns.
Four matrices were created, one for each of the separate herpetofaunal Orders of the Northeast:
Anura, Caudata, Testudines, and Squamata.
Over the past four years, NEPARC members have populated these matrices using the scientific
literature to answer these questions for each species. The goal was to provide as complete a
picture as possible of the status of northeast amphibians and reptiles, as well as of the status
of our knowledge of the species. Volunteers were assigned at each of the annual NEPARC meetings
to devote time towards each matrix. All information entered into the table included supporting
literature citations where possible.
Because NEPARC intends to periodically update these files, they have been given a version number.
The files presented here represent Version 1.0 of the Risk Assessment data matrices. We hope that
from the data provided in these matrices, we can help to drive research efforts on northeastern
herpetofauna.
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In populating the matrices, one preliminary finding is that much still remains unknown
for many species, and for many question categories. In this first version of the Risk
Assessment matrices, cells that are marked as "unknown" represent topics for
which either a) we were unable to find data where data may or may not actually exist, or
b) the published literature actually states that the data are unknown. Users should be
cautioned that these data files are intended as a starting point or as one of several
research tools, not as an exhaustive review of the scientific literature.
In addition, although literature citations are provided for data where possible, there are
some instances where data are present in a cell, but no citation is provided. We chose not
to delete such records, as they may still provide some value. If you are aware of an appropriate
citation please contact us. With each version we hope this
document and associated files will come closer to representing what truly is known and unknown
about these species and hope that this first effort will inspire others to contribute to making
these data more complete. Because of the amount of unknowns in the matrices, we have created
summaries of these gaps in our knowledge for each taxonomic group (below). The goal of these
summaries is to help users to identify species or topics lacking research data, and thus may
encourage the development of research questions and projects by graduate students and scientists
studying northeastern herpetofauna.
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Generally, much is still unknown for most species in all four taxa. Only the category of
Global Rank is an exception; this information was obtained for all species via the
Nature Conservancy's NatureServe
Conservation Status Ranks (off-site link).
As one might expect, anurans are most well-studied of the herpetofaunal Orders. In the
category of habitat, for all taxa, data are minimal or lacking for amounts of riparian or
wooded buffer needed to sustain breeding/nesting, feeding, and hibernation activities. Life
history traits for all taxa that remain poorly understood include natural longevity, age at
sexual maturity, percent of eggs surviving to adulthood, and collection/harvest pressures or
amounts. Movement and habitat use data are especially lacking for territory (if applicable)
and home range sizes, as well as for density per hectare. More detailed summaries, by taxonomic
Order, follow below and are organized into the vulnerability categories presented in the species
matrices. Only the categories where major gaps in our knowledge were identified are listed below.
Anura (Frogs and Toads)
This taxonomic Order is most well-studied among herpetofauna in the northeastern United States.
- Habitat: With the exception of American toad (Bufo
americanus), the amount of riparian buffer needed to support
breeding, foraging, and hibernating activities requires further
investigation.
- Life History and Demographic Traits: Areas requiring
further study include natural longevity, female reproductive behavior
(annually or more than once per year), percent of egg survival to
adulthood, and whether and for what purpose species are collected
by humans.
- Movement and Use of Habitat: In this category,
data overall are lacking. Specifically, subjects that remain poorly
understood include, territory size (if applicable), home range,
maximum and average distance that the species moves, whether the
species hibernates in an aggregation, and population density per
hectare.
Caudata (Salamanders and Newts)
- Habitat: For most salamanders data are lacking
for whether species can survive in urban and suburban environments
and whether they are negatively impacted by introduced species.
With the exception of ambystomatids and green salamanders (Aneides
aeneus), the amount of riparian buffer required to support breeding,
foraging, and hibernating activities has not been well-studied.
For sirenids, and some plethodontids (including members of Genera
Desmognathus, Plethodon, and Pseudotriton), habitats used for hibernacula
are not known.
- Life History and Demographic Traits: In this category,
the secretive nature of plethodontid species leaves many areas open
for further investigation. Specifically, additional study is needed
to determine specialized feeding requirements (if any), natural
longevity, age at sexual maturity, specialized breeding requirements
(if any), female reproductive behavior (once or more per year),
percent of egg survival to adulthood, activity period, and collection
pressures by humans.
- Movement and Use of Habitat: With the exception
of ambystomatids, data are scarce for most species in this category.
In particular, juvenile dispersal and adult movement (including
impact of road kill), and territory and home range sizes remain
poorly understood.
- Miscellaneous: Most ambystomatids are documented
to have toxic secretions, but information is lacking for whether
toxic secretions (if any) are produced by sirenids, amphiumids,
and many plethodontids.
Squamata (Snakes and Lizards)
- Habitat: With the exception of smooth green snakes
(Opheodrys vernalis), the amount of riparian buffer necessary
to support breeding, foraging, and hibernating activities is yet
unknown. In addition, further study is necessary to determine the
impacts of habitat fragmentation and introduced species, as well
as the ability of species to survive in urban and suburban areas.
- Life History and Demographic Traits: For most species,
data are lacking on natural longevity, specialized breeding requirements
(if any), and percent egg survival to adulthood.
- Movement and Use of Habitat: Although few studies
have examined squamate movement, data are generally lacking for
many species in this category. In particular, juvenile dispersal
and adult movement (including territory size, home range, and impact
of road kill) as well as population density and distribution remain
largely unknown.
Testudines (Sea and Freshwater Turtles)
- Habitat: Although knowledge of terrestrial habitats
utilized is well established for sea turtles and nesting freshwater
turtles, it remains poorly understood for non-nesting freshwater
turtles. In addition, further study is necessary to determine the
impact of habitat fragmentation and introduced species, as well
as whether species are able to survive in urban and suburban areas.
One problem identified with the question of riparian or wooded buffer
needed is that although this is not relevant for many turtles, data
are known to exist on the topic of buffer distances for occupied
wetland habitats; we were unable to include these data in this version
of the Testudines Data Matrix.
- Life History and Demographic Traits: Much data
are lacking within this category. Specifically, natural longevity,
age at sexual maturity (which may differ within the northeast region),
and the specifics of mating versus nesting behaviors and requirements
need additional study. Although the active season is well-documented,
summer aestivation periods may be poorly understood. Finally the
extent of collection pressures is not well understood, especially
for freshwater turtles.
- Movement and Use of Habitat: Data are most scarce
in this category. In particular, juvenile dispersal and adult movement
patterns (including territory size, home range, and impact of road
kill) are generally not well known, though local populations of
a few species have been intensively studied. Breeding aggregations
are better understood than hibernation aggregations.
- Miscellaneous: Members of the families Kinosternidae
(mud and musk turtles) and Trionychidae (softshell turtles) are
lacking data on toxic secretions.
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Downloading the data - Because the full Risk Assessment data matrices are large and difficult
to read or print easily, we have created separate, printable files by question and by taxon. These
files are in .pdf format, for which users must have Adobe Acrobat Reader. If you do not have an
Adobe Acrobat Reader, you can download a free copy from Adobe (off-site link).
Upon request, NEPARC can provide the Excel spreadsheet containing the entire matrix for an Order.
Send email requests to Linda Weir (lweir@usgs.gov).
Global Rank
What is the species’ Global Heritage Status Rank?
Habitat
What aquatic habitats does the species utilize?
Is aquatic habitat specialized?
What terrestrial habitats does the species utilize?
Is terrestrial habitat specialized?
If aquatic, is species found in saltwater (S), brackish (B) or freshwater
(F); or combinations thereof?
Does the species hibernate in an aquatic or terrestrial habitat?
Can the species survive in urban/suburban environments?
How much riparian buffer or wooded area does the species need around
its breeding site?
Is the species endemic to the region?
Is the species negatively affected by habitat fragmentation?
Is the species negatively affected by introduced species?
Life History and Demographic Traits
Does the species have any feeding specializations?
What is the maximum longevity of the species? State in years; can
specify range or average if available. Specify if maximum longevity
differs between males (M) and females (F)
How long before the species reaches sexual maturity? State in years;
can specify range or average if available. Specify if age at maturity
differs between males (M) and females F)
Does reproduction occur on land or water (i.e., are eggs laid on land
or in water)?
When is the courtship season for this species? Specify range of months
When is the egg laying season for this species? Specify range of months
from when eggs are laid until eggs hatch.
Are there any special requirements, circumstances or habitat needs
for breeding or can the species breed in many types of situations,
habitats or circumstances?
How many eggs does a female lay at one time? State the number of eggs
per female.
Do females reproduce every year?
Can females breed more than once each season?
What percent of eggs survive to adulthood? State as < 25%, 26-75%,
or > 75%
Does incubation temperature affect the sex of the hatchlings?
When is the active season for the species? Specify range of months.
Is the species collected by humans? If so, for what purpose (e.g.,
food, cultural/ceremonial, medicinal, bait for fishing, killed/persecuted,
pet trade)?
Movement and Use of Habitat
How far do the young of the species disperse from natal sites? State
in meters (m) or kilometers (km)
Does the species disperse across pavement or roads and is roadkill
a problem?
Can the species travel through agricultural fields?
What is the territory size for the species? State in m2 or km2
What is the home range size for the species? State in m2 or km2
What is the maximum distance the species moves? State in m or km
What is the average distance the species moves? State in m or km
Do individuals congregate in large numbers for breeding or hibernation?
What typical population density could you expect for the species in
a hectare of ideal habitat? State as < 10, 11-50, 51-100, 101-1000,
or > 1000 individuals
Are adults strongly philopatric?
Is the geographic range of the species increasing (I), decreasing
(D), or staying the same (S)?
Miscellaneous
Does the species produce toxic skin secretions or is it venomous/poisonous?
Bibliographies
The bibliography for each taxonomic group is provided below.
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We thank the following people for compiling the information:
- Anura: Sara Faust, Robin Jung, Priya Nanjappa, Chris Raithel, and Ed Schwartzman
- Caudata: Ariana Breisch, Isaac Chellman, Sara Faust, Zach Felix, Rob Fiorentino,
Tom Pauley, Mizuki Takahashi, and Jessica Wooten
- Squamata: Sara Faust, Emily Hall, Art Hulse, Robin Jung, and Sheera Schneider
- Testudines: Isaac Chellman, Sara Faust, Lindsay D. Funk, Tim Repickey, and Sheera Schneider
We thank the following people for examining the matrices to assess the gaps in our knowledge:
- Anura: Mary Beth Kolosvary
- Caudata: Jennifer Wykle
- Squamata: Diana Spendelow and Linda Weir
- Testudines: Mike Marchand
We thank the following people for assistance with the bibliography and website preparation:
- Kinard Boone, Jessica DeThomas, Lynda Garrett, Mike Marchand, Crystalina McGrail, Priya Nanjappa, Chris Raithel, Scott Smith, Diana Spendelow, and Linda Weir
Visit our parent organization, Partners in Amphibian and Reptile Conservation (PARC), for more information on national conservation efforts and other regional groups.