Herpetological Research at
 St. Marks National Wildlife Refuge

1 May 2003

Investigators:                                                  click images to enlarge
Margaret Gunzburger, Dr. C. Kenneth Dodd, Jr., Jamie Barichivich, Jennifer Staiger

Background:
In response to documented declines of amphibians, the U.S. Geological Survey (USGS), as directed by Congress in 2000, initiated the Amphibian Research and Monitoring Initiative (ARMI). The primary goal of ARMI is to monitor trends in amphibian populations on DOI lands and conduct research into causes if declines are observed. USGS herpetologists in the southeastern ARMI region (SE ARMI) are responsible for monitoring amphibians in Florida, Georgia, Alabama, South Carolina, North Carolina, Tennessee, Puerto Rico, and the US Virgin Islands. To date, SE ARMI personnel have established monitoring sites at several DOI lands in the southeast. As part of ARMI, we will conduct an inventory of the herpetofauna on the St. Marks National Wildlife Refuge and establish a long-term monitoring program for amphibians on the Refuge.

Inventory:
The objective of the inventory is to establish a current amphibian species list for the Refuge. A robust inventory of amphibian species richness is necessary to design the long-term monitoring study. To develop the list we will use a variety of methods to capture and observe amphibians in all habitats throughout the Refuge.  We propose to conduct general surveys and trapping across upland and wetland habitats and on many of the pine/palm islands. General surveys include field searching for animals under cover objects (i.e., logs and rocks), listening for calling frogs (i.e., aural surveys with frog loggers), and road cruising.  Trapping methods include using dip nets, seine nets, funnel traps, "siren" traps, turtle traps, and Goin dredges.  We will focus much of our inventory work at wetlands because this should allow us to maximize detection probability for most amphibian species on the Refuge.  We will also document our observations of reptiles and generate a current reptile species list for the Refuge.

Amphibian Monitoring:
The objective of monitoring is to determine long-term trends of amphibian populations on the Refuge. To do this we propose to establish numerous semi-permanent sampling stations at randomly chosen sites across broad habitat types (i.e., intensive sites). We also will conduct less intensive sampling at numerous randomly chosen locations (i.e., extensive sites).  The exact number and location of these sites will be determined later in consultation with Refuge staff, biometricians, and SE ARMI herpetologists.

Intensive Sites—At intensive sites we may erect a drift fence array consisting of metal flashing or silt fence buried ca. 20 cm in the ground.  The specific design of the drift fences has not yet been determined.  Wire-screen funnel traps will be placed at the ends of the drift fences to capture animals.  Traps will be shaded and checked frequently to keep mortality of trapped animals to a minimum.  A grid of PVC pipes (some hung on trees, others placed upright in the ground) and cover boards will be established at each intensive site.  Intensive sites will likely be monitored four times a year with multiple visits during each sample period. PVC pipes and cover boards will remain in place constantly, but funnel traps will only be deployed during sample periods. If intensive sites are located at wetlands, the wetlands will be sampled (see above methods) during each sample period in which they hold water.

We will incorporate many of the sites sampled by the U.S. Fish & Wildlife Service in the late 1970s in our study design. This will allow us to take advantage of historical data that was collected on the amphibian (and reptile) fauna of the Refuge approx. 25 years ago.  We will use appropriate statistical analyses to compare community parameters (e.g., species richness, relative abundance) between the historical and current data sets.  Using program PRESENCE, we will estimate detection probabilities of species captured and use this information to help us design our long-term monitoring strategy. This portion of the study will also allow us to compare the efficiency of the drift fence method with less intense methods to detect amphibians. We will erect drift fence arrays at 12 of the 14 locations studies by the USFWS in the late 1970's. We plan to follow their protocols with the exception that we will only install one array at each site (they used two arrays per site) and we will run traps at the arrays one week a month for two years (they ran traps constantly for two years). Funnel traps will be opened and suspended in trees and lids will be placed on pitfall when we are not sampling.  We will collaborate with the Florida Fish and Wildlife Conservation Commission (Kevin Enge) on this part of our work, if time and budgets permit.

Extensive Sites—No permanent equipment will be deployed at extensive sites. At these sites we will use time-constrained searches (turning natural cover and looking through leaf litter) and funnel traps at upland sites and dip nets and frog loggers at wetland sites.  Only one sample period will be conducted at extensive sites. The sample period will most likely consist of 2-3 consecutive days.

Disease Monitoring:
The objective of disease monitoring is to establish baseline data on the health of several target amphibian species so that potential declines caused by disease can be detected and dealt with. Following USGS standard operating procedures we propose to collect individuals of three species (to be determined) to send to our National Wildlife Health Center.  We would need to collect 10 breeding age adults, 10-15 tadpoles, and 2-3 partial egg masses for each species.  We also propose to collect specimens of any sick or dead amphibians we encounter.

Abiotic Parameters:
The objective of collecting abiotic parameters is to identify factors that influence distribution, activity, and detection probability of amphibians. Examples of abiotic parameters that we propose to collect at each sample site include relative humidity; air, water (at wetlands), and soil temperature; pH and salinity (at wetlands); etc. Cooperators from the USGS Water Resources Division will collect water samples from several of our study sites. We may also collect soil samples.

Species Vouchers:
The objective of collecting voucher specimens is to create an archived record of species presence on the Refuge.  All voucher specimens will be donated to the herpetology collection at the Florida Museum of Natural History at the University of Florida.  Vouchers will consist of preserved specimens, digital photos of individuals, and acoustic recordings of calling frogs. Specimens to be preserved include road-killed amphibians and reptiles and several individuals of relatively common species.  Rare or listed species will only be vouched with digital photos, or a single individual may be collected after consultation with Refuge staff.

Some species of salamanders and frogs are difficult to identify while they are larvae. Therefore, we propose to occasionally collect several individuals per putative species and rear them in the lab to confirm species identification.  After these individuals are reared to metamorphosis and the species is confirmed, they will be preserved as vouchers.

Deliverables:
We will provide the Refuge:

• A current annotated list of herpetofauna species
• A link to our website with photos and descriptions of herpetofauna species encountered on the Refuge
• A laminated poster about our work at the Refuge and species observed
• A list of voucher specimens collected with museum catalog numbers
• Digital photos of species observed on the Refuge
• An annual report summarizing our work at the Refuge