Mosquitoes beware, Pacific Tree Frogs are here!

We have tree frogs in the bog! The latin species name is Hyla regilla. This year we have had a bumper crop of tadpoles in the pond. On Thursday, I was told the frogs had started climbing out of the pond, so I went there to see. I found all the different life stages, except for complete tadpoles and tail-less frogs. The frogs are only about as big as your thumbnail, from head to toe.

Tadpole with hind legs

Tadpole with the head of a frog, and hind legs

Salamanders, tadpoles, and a little shrew

The attached picture is the cluster of eggs Heather found while pulling Juncus out of the bog on Sat. morning. They are not frogs eggs so we surmise they may be salamanders. If you look closely you can see the external gills.  There are also "tons" of tadpoles in the pond! All that croaking in early spring by the adults has produced a bumper crop. Frogs may be disappearing in other locations around the world but lets hope our Tree Frogs have found a permanent home in the bog.

    Gerry

Sphagnum Moss from Camosun Bog

All photos copyright Gerry Mignault,  CBRG

The keystone species in Camosun bog is Sphagnum moss, sometimes called peat moss.  Without Sphagnum , the bog would not exist. Sphagnum maintains the wet and acidic conditions favoured by bog plants.  It has the incredible ability to absorb water like a super sponge and it pumps hydrogen ions into its surroundings, thus creating a very acidic environment. 


Sphagnum moss is a Bryophyte, one of the earliest plants to colonize land in evolutionary history. It doesn't have many of the adaptations shared by more recent land plants:   Lacks a cuticle (no shiny waxy protective covering - lip balm for plants!) Has no vascular system, the xylem and phloem (the "arteries and veins" of later land plants - maple syrup is tree "blood" drizzled on our pancakes!).


Sphagnum shares many characteristics with its close relatives, the aquatic plants.  like seaweed, it has swimming sperm. Thus sphagnum requires constant water for sexual reproduction.  Observe Gerry's  photos of Camosun bog's range of Sphagnum moss varieties.

more pictures below

Tree Frogs vs Bullfrogs

It is very easy to know if you are looking at a tree frog or a bullfrog.

   Tree frogs are very small – 2-4cm long. They come in two colour phases – either brown with dark blotches or bright green. They always have a black stripe running from their nose past the eye and down to the shoulder. They make a “ricket-ricket” sound way out of proportion to their size http://www.naturesongs.com/frog3.wav
  Bullfrogs make a quite different sound, rather like a rapidly repeating foghorn http://www.learnnc.org/lp/media/collections/fieldguide/frogcalls/bullfrog.mp3 They are far bigger than tree frogs – up to 25cm and can weigh up to 2kg.. They expand like balloons when attacked and have teeth on their lower jaw to hold their prey. They eat almost anything. They were introduced from Africa and are a thoroughly nasty species in this area.

A Frog in the Bog

When I moved into my home near Camosun Bog over 30 years ago, the sound of frogs in the spring was deafening. Over the years the sound decreased and in the last few years the bog has been silent.


One major reason for the loss of tree frogs has been bullfrogs. These were introduced to this area in the 1930s to produce frog legs for French restaurants. They didn’t catch on and were released in the Langley area. They have almost no predators – possibly herons – and each female produces 20,000 eggs every year. They can travel 1½ km in an evening and jump 2m high. There are reports of them eating cats! (see http://www.barbelith.com/topic/2486)

They arrived in Camosun Bog 7-8 years ago and very quickly eliminated the remaining tree frogs. Having eaten them all, the bullfrogs then moved on to happier hunting grounds.

Over the last couple of years, the tree frogs have started to move back into the bog. This may be due to us expanding and deepening the pond and particularly this year it may have been helped by the very wet spring we have had. At one work party in April we were deafened by their sound and had to shout to be heard. The inevitable male-female thing happened and now we have lots of tadpoles swimming around in the pond!

Let’s hope the tree frog population continues to increase. It is essential that we do not disturb the tadpoles and we must not allow anybody to collect them. There is a real danger that the sound of the peepers will attract the bullfrogs and they will return to wipe out the population again. Unfortunately there is not much we can do to stop this. We tried to catch them some years ago but we were never successful as they disappear as soon as someone approaches them. Probably we will get into a long-term cycle of gradually increasing population followed by a crash. Rather similar to the lemming – snowy owl cycle in the arctic. We will see…..