Vernal pools are micro habitats; temporary ponds occurring in depressions in the ground. They're created by snow melt, spring rains and otherwise pooling water. They hold water during the spring, dry up during the summer, and refill in the fall. The lack of fish in these ponds is important to the survival of amphibian eggs, as they would prey upon the eggs and growing young.
Vernal pools (and the animals that rely upon them) are very sensitive to environmental conditions, like temperature and contaminants. How long they last depend on some key factors; precipitation, proximity to other wetlands, size, surrounding vegetation, and access to groundwater. As climate change also affects them by changing precipitation rates and temperature. This alters the timing of pool formation which then causes reproductive failure as amphibian larvae are unable to metamorphose before the pools dry. Contaminants like acid rain and disease will cause complete failure of eggs to develop. This is why it's important to protect both the animals and their habitats.
Solarpowered and superpowered
Amphibians are unique and amazing in many respects. They change their body plans, breathe through their skin, are specialized for bizarre locomotion, some don't even have lungs, they survive being frozen solid, mummify themselves, are sometimes transparent, blind aliens (remember that stage from "Earthworm Jim 2"?). Some eel-like amphibians called amphiuma, possess one of the largest known genomes in the animal kingdom. Sirens are unique to North America. Besides that, they are gentle, quiet (well, mostly) bug control specialists who go overlooked for their vitally important role in their ecological niches. They make up a huge percentage of the biota of temperate forests - some estimates ranging as high as 90 percent - and therefore sustain the populations of nearly all other forest dwellers.
Also, spotted salamanders are literally. Solar. Powered. They have harnessed algae inside their own skin cells and draw oxygen and carbohydrates from the photosynthesizing algae. If it was a Pokemon, it would be Grass/Ground type.