Going to the pool in winter (Vernal Pool)

We've had some warm and rainy February days out here at the Edge of Appalachia Preserve, and that means its time to check the vernal pools and see what kind of amphibian activity has occurred.  Vernal pools are wet places that hold water in the winter and spring, but dry up in the summer and fall.  They can be ponds in a field, roadside ditches or any depression that holds a little bit of water half the year.  If a vernal pool has been established for many years, there's a good chance frogs, toads and salamanders have used it as breeding pools for egg laying.  They choose vernal pools because they hold water long enough for the presence of food sources  (i.e. insects, amphipods etc.), but not long enough for prey species to become established (i.e. fish).

 

This wet field in the winter is a great vernal pool for amphibian mating

I checked a couple pools on the preserve this week to see what has been moving.  There are a few salamander species that use these pools this early and couple of frogs as well.  Scooping a net in a pool produced a few inch-long salamander larva.  Any larva that large in a pool in February would have to be that of the marbled salamander, Ambystoma opacum.  And these were indeed marbled larva.  Marbled salamanders mate and lay their eggs in September within the pool boundaries when it's waterless.  Throughout winter, as the water fills the pool, the eggs hatch and the larva start growing before any other species lays eggs in the pool.  The adult pictured below was from the fall, only larva are found in the pool in February. 

 

Marbled salamander (Ambystoma opacum) from September.  Larva are now swimming in the vernal pools

Also within the pool were small clumps of gelatinous eggs holding Jefferson salamander, Ambystoma jeffersonianum, larva.  I did not find any adult Jefferson salamanders in the pool, but did find an adult under a rock at the edge of the pool.  Jefferson salamanders will move to the pools to mate at the first warm (>55F) rainy nights in the winter.  I have found eggs in pools as early as December 27th.  But February is the typical time for mass movements of these salamanders.  Years ago I was doing recruitment surveys for a state herpetologist. During this survey, I (with the help of Rich McCarty TNC) counted 270 Jefferson's, and that was only what was in the traps.  I can count the thumb on one hand, and that's the number of Jefferson salamanders I have seen in the wild that were NOT in or around a vernal pool.  So if you wanted to find one....now's the time.

 

Jefferson salamander (Ambystoma jeffersonianum) under rock at edge of pool

Also in February the spotted salamanders, Ambystoma maculatum, will be moving in mass to these same pools.  They are historically a little bit later than Jefferson's, but are due.  I just didn't see any this day.  All three of the salamanders mentioned above are often called mole salamanders because they spend most of their life underground.  This is why they are so hard to find, unless, you know about their breeding habits and when and where to look for the annual movements to vernal pool.

 

Spotted salamander (Ambystoma maculatum) found in previous years but not from this week. 

 

Ambystoma salamander eggs in a vernal pool.  Much smaller clump than the woodfrogs.  Clump on the left looks like it was laid much earlier than clump on the right.

I couldn't help but notice a huge mass of eggs at the end of one of the pools.  This is typical of the woodfrogs, Lithobates sylvaticus.  The weekend before, woodfrogs were calling  all over the county.  Unlike the salamanders, the early spring frogs give you a signal that the time is here.  And you can hear it from far away, leading you to these vernal pools.  In February, spring peepers, Pseudacris crucifer, and woodfrogs are the only species tolerant enough to withstand the cold temperatures before and after the egg-laying.  Both were heard calling throughout the day.  But only the woodfrog leaves the massive amounts of eggs like these shown below this time of year.

 

Although under water, you can still see large numbers of clumps of woodfrog eggs.  Each black dot is one egg.

 

Woodfrog (Lithobates sylvaticus) eggs sticking to a branch.

Many spring peepers were found in and around one of the vernal pools, but their eggs are harder to find.  They also don't have as short of a breeding period as the woodfrogs.  You can hear spring peepers calling well into April and maybe May.  Woodfrogs are true winter breeders.  They even are adapted to freeze solid and still survive.  Even if the vernal pool freezes again this year, many of the eggs are structured to survive.  The black side of each egg faces the sun to absorb heat and keep from freezing.

Spring peeper (Pseudacris crucifer) hiding in the grasses near the vernal pool.
 

 



Woodfrog (Lithobates sylvaticus)

To hear woodfrogs and spring peepers calling in one of our vernal pools, listen to the video below.  The spring peepers  are the high pitched whistles and the woodfrogs are the quacking chatters in the background.

Some of these species are very hard to find in the wild.  But if you learn the life histories of each species, you can definitely learn the tricks of where and when to look.  Finding the eggs in the pools and hearing the calls of the frogs, to me,  represent the first real signs that spring is right around the corner.  The amphibians' annual ritual of visiting these pools have created an annual ritualistic hunt for myself and many naturalist that brightens up the long gray winter.

For more information about these vernal pool species, check out Amphibians of Ohio, 2013 from Ohio Biological Survey’s website here.  This book contains an enormous amount of information about all of Ohio’s amphibians.
  
Posted by: Mark Zloba

Five minutes under a rock

Curiosity is a funny thing and I hope I never lose it.  While walking through a field, I stopped to photograph a lichen growing on exposed dolostone rock.  Although locally common, statewide it is a very uncommon lichen called Psora pseudorussellii.  Pictured below, it is a squamulose lichen attractively colored with red apothecia (red discs which are the fruiting bodies of the fungus).  



Psora pseudorussellii

After photographing the lichen, I noticed a smaller rock nearby, a little bigger than a football.  Like a dog to a fire hydrant, I am attracted to rocks I think I can lift.  I can't seem to shake the curious question of "what is under that, and every rock"?   And of course, there is always the chance of finding something I haven't seen before, so why not take a look.



The rock.  A piece of Peebles dolostone.

So I took about five minutes to quickly look and see what animals I could find (at least visible to the naked eye).  Almost immediately, two critters disappeared into the cracks of the ground before I could get a picture.  One was a common exotic earthworm called Lumbricus rubellus.  Everyone has seen this worm before, and it is not too hard to identify if you can recognize its faint red wine color.  The second was a sowbug or wood louse (sowbugs can't roll into a ball like pilbugs, Armadillidium sp., but look similar) called Trachelipus rathkei.  T. rathkei is a fast, 2-tailed sowbug and also an exotic species.  Both of these are expected under rocks at the "Edge".

But a few animals stuck around long enough to photograph, or proof of the animals existence was there.  A female wood roach, Parcoblatta sp., stood still long enough for a pic.  A few leafhoppers showed up after I lifted the rock.  These little hoppers from the genus Erythroneura jumped into the soil under the rock, but I think were in the grasses beside the rock and not underneath.  All pictured below.





  Parcoblatta sp. of wood roach commonly found under rocks and logs on the preserve.

Erythroneura sp. leafhopper showing very attractive pattern.  Many leafhoppers are just as showy as the prettiest butterflies.........in my opinion.



Another Erythroneura  leafhopper, barely a millimeter in size

What got my attention in those few minutes of looking under that rock were the amount of micro-snails (<5mm) and/or snail shells on the rock or in the dirt underneath.  I quickly counted the species I could identify, and collected a couple of shells I knew would require a scope for identification.



If you look closely you might find snail shells under the rock

Most shells will blend in well with the soil or rock, so you need to search carefully.  Here a Catinella vermeta blends in.

Many small land snails can be found under rocks and woody debris on the ground as well as grass thatch where it meets the soil.  This particular rock had 14 individual snail shells found within this short search time.  None of them larger than 4 millimeters.  Luckily, land snails are easily identifiable by using their shell, so if the animal is dead, you can still identify it to species.  They were: the white-lipped dagger, Pupoides albilabris, 2, the armed snaggletooth, Gastrocopta armifera, 4, the minute gem, Hawaiia miniscula, 3, the suboval ambersnail, Catinella vermeta, 2, the wild hive, Euconulus chersinus, 2 and 1 small unknown Gastrocopta.  



2 snail shells.  The one on the right shows the "teeth" of the shell opening giving reason to the common name armed snaggletooth snail.

Armed snaggletooth, Gastrocopta armifera shell

 I wanted to take a closer look at the small unknown Gastrocopta. I was hoping it was the rare species Gastrocopta rogersensis, which was newly described in 2001 in Iowa, only to be found a couple years later here at the Edge by one of it's author's Jeff Nekola.  The range of this species is hundreds of miles west of the Edge, making his find a disjunct anomaly like so many other species found on this preserve.  Since his discovery of this overlooked land snail, I have found them in 2 other prairies on the preserve.  But it would be nice to extend its range within the preserve.


White-lipped dagger, Pupoides albilabris shell hiding in the mud.

Once back in the lab, and the few collected snails were placed "mouth up" under the dissecting scope, I could easily see "tooth" features in the opening of the shells.  My curiosity driving me to wonder what was under that rock has led me to an exciting find (at least to a small circle of maloco-phile folks).  I believe the mystery snail is Roger's snaggletooth (Gastrocopta rogersensis), the newly described species mentioned above.  This adds a fourth location of this snail on the preserve.



Here you can see the size difference in three of the shells. Gastrocopta rogersensis (>2mm), Hawaiia miniscula (2mm) and Pupoides albilabris (4mm).  So 4mm is a big snail under this rock.

These were just the larger animals I could see in a five minutes.  Just imagine how many creatures there really are if you could count the micro inhabitants under this rock.  I need to remember this when I am out looking under rocks and logs.  I should be a little more deliberate when putting a rock back in its place.  And maybe, hiding under the next piece of debris, an un-described species will be found, unknowingly waiting to be discovered.  Just curious.

Posted by:  Mark Zloba