The past couple of weeks while we have been out surveying migrating birds and spring ephemeral flowers, we have also seen lots of amphibian activity as well. Last week while up at College Lodge, we came across a few very productive vernal pools. The water levels were relatively low, causing a bit of concern that the pools may dry up before the amphibians could develop from tadpoles and larvae to land conquering salamanders and frogs. However, all this week’s rains have filled up the pools nicely, giving more time for the amphibians to develop. Here are a few photos of our findings.
Because spotted salamander (Ambystoma maculatum) eggs are in a tight mass, it is difficult for needed oxygen to circulate to each of the developing embryos. However, through a symbiotic relationship with green algae (Oophila amblystomatis), the embryos within the outer and inner parts of the mass are able to acquire the oxygen they need from the algae which produces it. The algae benefits from the eggs similarly by gaining carbon dioxide, produced by the embryos, needed for photosynthetic processes.
Spotted salamander larvae are long bodied and develop their forelimbs first, as apposed to frogs which first develop their hind limbs. Spotted salamander larvae are fantastic predators within the vernal pools and will eat a number of small insects, aquatic invertebrates, crustaceans and even other salamander larvae. Frog tadpoles, on the other hand, quietly rasp algae and other plant material from the pool and in this case from the outsides of other egg masses.
Here’s a close-up of a spotted salamander egg mass.
In comparison, wood frog (Rana sylvatica) egg masses are looser than spotted salamander’s and have small channels within them, allowing oxygen to be transported to the developing embryos via water convection. Wood frog eggs also share a symbiotic relationship with O.amblystomatis and studies have noted that masses with the algae often result in higher hatching success and shorter development time as opposed to masses without it.
Here’s a close-up of a wood frog egg mass. Can you see the differences from the spotted salamander egg mass?
And here is a close-up of the wood frog tadpoles. Their bodies are darker in color but they have a light colored underside, making them distinguishable from other dark bodied tadpoles such as the American toad (Bufo americanus).
It will only be a matter of a couple short months before these little ones lose the frilly gills and rasping mouth parts in exchange for lungs and legs, making their transition to terrestrial life. The newly developed salamanders and frogs will face a number of new challenges that come with land life, but we can certainly make their lives a bit easier by caring for the habitats in which they are found and prevent further disturbances to these sensitive areas. Join us this summer in appreciating, learning about and conserving these special species and the incredible habitats they are found in. This is the year of the salamander, so let’s make it a great one!
Elyse Henshaw
Conservation Technician
