Amphibian Cover Board Monthly Check - July 2012

Red-backed Salamander with six newly hatched salamanders.
Photo by Erin Caruso 

Today’s monthly check of the amphibian cover board experiment grid revealed forty-six individual salamanders. The amphibians that Nicole Morin and I came across were mostly Red-backed Salamanders, although we did see five Red Eft, one Northern Two-lined Salamander, and one Wood Frog. Twenty-two Red-backed Salamanders were under the softwood cover boards and eighteen were discovered under the hardwood. Two of Red-backed Salamanders under the softwood were found coiled around their young. This was an exciting event to come across because this strengthens our theory that the cover boards provide a favorable habitat for salamander reproduction. In addition, their population growth signifies a healthy forest environment. When it comes to reproduction, Red-backed Salamanders are unique because they lay their eggs on land, while most other amphibians and salamanders such as the Blue-spotted Salamander attach their eggs to underwater twigs or vegetation. These underwater eggs hatch and go through an aquatic larva stage. In contrast, the Red-backed Salamander young go through the larva stage while still in the egg, and when they hatch, look like miniature adults. Since the month of August is usually when most salamanders emerge from their eggs, it will be interesting to return to the cover board experiment grid at the end of next month and see if we can find a higher abundance of baby salamanders.

Lead phase Red-backed Salamander with egg cluster.
Photo by Erin Caruso

Amphibian Cover Board Monthly Check - June 2012

On Tuesday, June 19^th James Fischer and I went out to the Solnit Parcel to do the monthly check of the experimental amphibian cover board grid. We were able to encounter 93 salamanders; 45 under the softwood boards and 48 under the hardwood boards. The majority were Red-back salamanders, although we did see 2 Four-toed salamanders, 17 Red Eft, and one wood frog. We noticed that most of the salamanders that we found were located in areas of dense fern stands. These ferns provide lush habitat for amphibians by keeping moisture and leaf mold intact.



Four-toed Salamander (Hemidactylium scutatum)

We were lucky enough to find a female lead phase Red-backed salamander guarding her eggs underneath a hardwood board. This is not a common spectacle to come across because Red-backed salamanders only mate every other year. After laying her eggs the female will coil her body around them and protect the eggs for two months until they hatch. The eggs are laid in a cluster, so they are somewhat difficult to count, but I estimated there to be 30 eggs in the cluster. Once the eggs hatch the baby salamanders look like miniature adults and after two years will reach reproductive maturity.



Red-backed salamander (Plethodon cinereus) with eggs.

Amphibian Cover-board Monthly Check -- November 2011

Redback Salamander (Plethodon cinereus)

Winter is here or at least the amphibian's behavior suggests it has arrived.  We encountered only 7 Redback Salamanders during Friday's visit to the grid.  Faye Curran and Abby Conroy helped with today's check and we were all thrilled to see the few salamanders that we observed.  The temperature was about 35 degrees Fahrenheit with a clear sky and only a slight breeze.  All of the salamanders were observed under cover-board stations under deciduous tree cover.  I think this is due in large part to the lack of leaves in the trees to shade the ground which exposes the ground to more solar radiation.  The cover-boards under the conifer canopy were very shaded and would have been cooler.  Thanks to Faye and Abby for a solid day's work, especially since we observed so few salamanders and it was rather chilly.  This will likely be our last check for the 2011 calendar year.  Check back to see when we return to the grid.

Amphibian Coverboard Experiment Monthly Check -- October 2011

Spotted Salamander (Ambystoma maculatum) discovered under a
cover-board just as it emerged from it's mole-like tunnel.
Photo by James Fischer  

I observed an amphibian at 57.6% of the cover-board (CB) stations yesterday.  This is the highest proportion of stations that detected an amphibian ever observed during our monthly visits to this site over the past 2.5 years!  This is exciting news but I want to tell you about another interesting observation that I made.

A yellow-hued Spring Peeper (Pseudacris crucifer) camouflaged
among newly fallen autumn leaves.
Photo by James Fischer  

The CB grid spans across two stands of trees, one stand is dominated by deciduous trees while the other are evergreen trees.  The CB stations under the deciduous trees detected more amphibians than the stations under the evergreen canopy.  This puzzled me while I was traversing the grid from station to station.  I walk the grid a systematic fashion so that it takes less time.  I walk the grid along the lines within the grid from the evergreen stand to the deciduous stand and back again.  But that question kept bugging me. Why were more amphibians observed under the CB's in the deciduous stand rather than the conifer stand?  I think I may know but I need to tell you about another pattern that I observed whilst walking the line.  This was a new pattern for me this season.  I was wearing my sunglasses while I was in the deciduous stand and not in the evergreen stand.  Okay, if I lost you, please keep reading because there is a reason why this is important.

Just as I was beginning to get frustrated with having to pull out my sunglasses from my pocket each time I entered into the deciduous stand, the light hit my eyes and my skin began to feel warm!  Yes, it was noteworthy moment but not the kind you may be thinking of.  I began to think that the amount of sunlight penetrating the forest floor could have been one factor causing this pattern.  It is now autumn in southern New England and many of the leaves have already fallen from the deciduous trees allowing more of the sunlight to reach the forest floor.  The CB's under the deciduous trees should be warmer than their evergreen counterparts, which explains why so many amphibians were observed under these boards.  But lets not rush to this conclusion too quickly!  There could be several other explanations.  I'll offer another possible process just to demonstrate how complex a walk in the woods can sometimes be to biologists and ecologists.

Northern Two-lined Salamander  (Eurycea bislineata) found
under a cover-board near a spring seep.
Photo by James Fischer

Another explanation could be that the leaf litter on the forest floor could also be warmer and more importantly dryer under the deciduous trees while the conifer stand could be cooler and moister.  The amphibians in the deciduous stands would seek out shelter that offers a moister environment.  The amphibians inhabiting the evergreen stand would not have to seek out these micro-habitats.  Moisture is very important to a group of organisms that breathe through their skin.  Moist skin allows for more oxygen to transpire than drier skin.  Amphibians breathe through their skin as an adaptation which has allowed them to lower their metabolism as they evolved which means they require less energy to live.

Who knew flipping cover-boards and a walk in the woods could be so complex...

Amphibian Cover-board Experiment -- Monthly Check

Red Eft Life Stage of the Red-spotted Newt
photo by James Fischer

We revisited the cover-board experiment grid and observed a few interesting patterns.  Faye Curran, a new student intern, helped us today with this project, please visit the blog in a couple days to read her introduction.  Recently, we have recorded almost 14 inches of rain from Hurricane/Tropical Storm Irene and Tropical Storm Lee.  Although most of the surface run-off has slowed, there is still quite a bit of water in the forest percolating into the soil column from vernal pools or bubbling out of springs.  The amphibian cover-boards encounter rate appears to have been affected by all of this precipitation.  A total of 65 of the 132 cover-board stations detected an amphibian, which is the second highest percentage of cover-board stations detecting amphibians since the project started 2.5 years ago.  We encountered a total of 79 Redback Salamander (Plethodon cinereus), 19 Red Eft (Notophthalmus viridescens), 2 Two-lined Salamander (Eurycea bislineata), 1 Four-toed Salamander (Hemidactylium scutatum), and 1 Wood Frog (Rana sylvatica).  The primary question of this project is to examine the differences between softwood and hardwood cover-boards amphibian detection rates using a pair-wise comparison experiment.  The softwood cover-boards detected a total of 57, while the hardwood boards detected 45 individuals.

Amphibian Cover-Board Experiment Monthly Check

Redback Salamander (Plethodon cinereus) observed under a cover-board.

This experiment compares softwood versus hardwood cover-boards to observe if there is a significant difference between the detection rates of amphibian species inhabiting our temperate forests.  Redback Salamander (Plethodon cinereus) and Red Eft juvenile form of the Red-spotted Newt (Notophthalmus viridescens) comprise the bulk of the amphibian species we observe in our study site.  We check the boards once a month when the weather conditions meet a specific set of criteria which insures the bulk of animals are found under the boards rather than wandering throughout the study area.  This experiment began two years ago and we are entering into our third season.  We hope to publish the results soon, but we observed 56 Redback salamanders under the softwood cover-boards and 41 under the hardwood cover-boards.  Only 2 Red Efts were found under the softwood boards while 5 were observed under the hardwood boards.  Considering that we had freezing temperatures most nights only a few weeks ago, these observations suggest that we have quite a few animals in our study site.  Check back to hear more about our progress with this experiment.