Nature Detectives
Vernal Pools
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In mid March, at the east side of Brightwood Park where it meets Prospect Street, there's what looks like a big puddle. That puddle, and others like it in the Park, can be critical to the life cycle of local amphibians. The eggs of frogs and toads, newts and salamanders, can only hatch if they are submerged in water. While the young animals develop the legs and lungs they will need to survive on land, they must breathe using gills, and gills only function in the water. So, for the time it takes to hatch and mature, amphibians must be under water.
With the two large ponds in the Park, why would amphibians risk laying their eggs in puddles that might evaporate before the young are ready to emerge? The answer is "fish". The big ponds are home to fish that would happily dine on the eggs or developing young of amphibians. Because the small pools evaporate by the end of summer, fish cannot live in them. This is why the puddles are called "vernal pools". They are only found starting in the spring, and they will be gone by the end of summer. Are there amphibian eggs in the vernal pools near Prospect Street and the Fanwood entrance? We don't know. It's not easy to get close enough to the pools to spot eggs or developing young. But there are frogs, toads, salamanders and newts in the Park, so it's a good bet that some of the pools are used as hatching grounds.
-by JPL with photos by JPL and sketch by Joan Miller
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