First 2014 die-off observed

First, to start off on a high note before the misery soon to follow, let me show you some new metamorphs! These cute little wood frogs are starting to emerge from the pools, and they can be found around Heiberg in various sizes and states of metamorphosis. Many things can affect the size of newly morphed frogs, including genetics, egg size, population density, competition, food availability, and cannibalism (yes, there are tadpole cannibals!). For a good basic read on the subject (Berven & Chadra 1988), click here. 

One pre-existing pool was surrounded by some of the tiniest emerging wood frogs I've ever seen! This one, at Gosner stage 45, was only about 7mm long.

This metamorph from a different site is nearly twice the body length (snout-vent) as the one above, but at Gosner stage 43-44 is not as far along in development.

Now for the doom and gloom. The artificial vernal pools in Heiberg Forest were constructed in groups of 1, 3, or 9 pools using a hexagonal grid to separate the groupings. Hexagon 5, the site of die-offs observed in previous years, has experienced yet another wood frog die-off beginning July 10 of this year. At least 3 of the 9 pools were affected. Most wood frog tadpoles had already died and begun decomposing, and those sampled alive were lethargic, swimming erratically, and/or had visible signs of ranavirus including sloughing skin, edema (swelling), and subcutaneous hemorrhaging. Although die-offs can happen very rapidly and are easily missed if diseased individuals die and decompose quickly, this appears to be the first one this year.

This wood frog tadpole clearly shows signs of edema. Poor little thing looked like a balloon compared to its poolmates.

Internal hemorrhaging can be seen in the lower abdomen

Mobile lab

The real side of fieldwork: hunched in the back of my Rav4 in 90 deg F processing samples while dodging mosquitos. Hungry little ****ers. Who would ever want a desk job!?

Welcome field assistants!!

The fieldwork is moving along efficiently tanks to our two field assistants: ESF senior Laura Labarge and ESF grad Logan Osterhoudt. Between sampling and hauling equipment around the woods, we couldn't do this without them!

ESF senior Laura Labarge having an amazing time pipe sampling

ESF grad Logan Osterhoudt enjoying some wonderful summer weather

Laura making a new friend (American Toad, Anaxyrus Americanus)

Other forest critters hang out by the pools (Eastern newt, juvenile eft stage, Notopthalamus viridescens)

My selfie with an adult Eastern newt

An adult green frog (Lithobates clamitans) hitching a ride on the sampling net

Field season begins!

The 2014 egg mass counts are complete, and it looks like it's going to be a productive year for wood frogs and spotted salamanders! Most of the wood frogs have hatched over the past few weeks, but the salamander embryos are still developing. The two egg masses can generally be distinguished by their shape and size. Wood frog egg masses are usually located at or near the surface, with black embryos visible inside the mass. Spotted salamanders usually attach their egg masses (which are typically smaller than wood frogs') to submerged vegetation and sticks. The salamander egg masses can also be identified by an outer jelly-like coating around the entire mass. Toads also lay their eggs in vernal pools in long strands.
 
Photo credits: T. Youker

Strand-like egg mass of the American toad (Anaxyrus americanus)

Spotted salamander (Ambystoma maculatum) egg mass, with visible outer jelly coating

Wood frog (Lithobates sylvaticus) egg mass

Egg masses often appear greenish due to the growth of a symbiotic algae,  Oophila amblystomatis. This algae is thought to aid in the circulation of oxygen to the developing embryos. Once the eggs hatch, emerging tadpoles feed on the remaining yolks, egg sacs, and algae. Below is a video of wood frog tadpoles hatching in one of the open field pools.

 

Wood frog tadpoles munching on their empty, algae-covered egg mass

Funding for The ARP

I am proud to say the Amphibian Ranavirus Project now has grant support from two sources: The SUNY ESF Maurice Alexander Wetland Graduate Award, and Western New York Herpetological Society Marv Aures/Bob Krantz Award. These awards will fund our summer field research this year, anticipated to begin with egg mass counts next month!

Some amphibian disease awareness

Amphibian diseases flow through animal trade 

Year of the Salamander

The Partners in Amphibian and Reptile Conservation and Wildlife Society have designated 2014 as "Year of the Salamander"! Visit parcplace.org and read State of the Salamander