Blue Hills A-Live: Vernal Pools Part 1 Transcript

Kyla Bennett tells us about vernal pools.


Judy: They exist only in the springtime but support key species in the Blue Hills. Today we’ll hear about how vernal pools are important to the Blue Hills and to all our conservation land. I’m Judy Leher Jacobs, the executive director of the Friends of the Blue Hills.


Kyla: I’m Kyla Bennett. I work for Public Employees for Environmental Responsibility and I have a PhD in ecology and evolutionary biology and a law degree.


Judy: Thanks for being here. And if you have seen any of these pools that pop up in the springtime let us know in the comments. We’d love to know. You are watching Blue Hills A- live, your weekly guide to the Blue Hills sponsored by Tom O’Neill of Success Real Estate in Milton and if you’re interested in helping out in the Blue Hills you’ll want to come to Green Up the Blue Hills on April 28th 9 o’clock at Houghton’s pond and we’ll put a link in the comments you can also go to Let’s start. So do you want to just start by talking about how you got interested in vernal pools to begin?


Kyla: Sure I have always been interested in animals, in particular frogs and salamanders. I always found them fascinating and when I was in college, I took a natural history class with a biology professor and he took us out into the field all the time and taught us about vernal pools and the frogs and salamanders and insects that lived there. Then, when I went to graduate school to get my PhD, my adviser was a frog guy, he was a herpetologist, so he really got me into the whole vernal pool thing.


Judy:  Wow so it’s been since college.


Kyla: Yes it’s been since college


Judy: So what’s special about vernal pools?


Kyla: Well what’s special about vernal pools is that there are really critical and vulnerable habitats for a number of different species– both invertebrates and vertebrates– and the reason that they’re so endangered is that, in the fall they dry up. There’s actually a vernal pool behind us that you might be able to see and in late summer this pool will totally dry up and it will just look like a depression in the ground and because of that when pools are outside of protected areas like the Blue Hills or any kind of state park or town conservation land, developers will often fill them not knowing what they are and they provide breeding habitat for a number of amphibians that can breed nowhere else. They are what we call “obligate vernal species” –they’re obligated to breed in these vernal pools and if you destroy them they oftentimes will not breed they won’t go find another pool at all.


Judy: So if you destroy vernal pools then what happens?

Kyla:  It destroys a number of species breeding grounds. What makes a vernal pool, basically, a vernal pool is just what we call a wicked big puddle here in Massachusetts. It’s something that fills up with rain and snowmelt in the spring, hence the word “vernal”, and it’s a depression that fills up with water, does not contain fish– it cannot have a breeding fish population, so when the pool dries up in the summer time and then the early fall fish would die if they lived there. And the reason it is important not to have fish is because the fish will eat both the tadpoles and the eggs. So these amphibians go in there, they breed leave their eggs and it’s kind of a race against time, where the eggs have to develop before the vernal pool dries up but it gives them protection from fish. So they can’t breed, for example, in a pond that have fish because they won’t be successful so they find these small pools, these small vernal pools, breed there and then they have a much better chance of reproductive success.


Judy:  That’s great. So if you have questions about vernal pools this is definitely the time to ask them, let us know in the comments. I was going to ask you about the “big night”?


Kyla: Yes, so usually every spring we have something called “big night” and that is the first warm (meaning over 40 degrees, not so warm, but for them it’s warm), the first warm, rainy night. The rainier, the better. And that’s when the amphibians will cross from their wintering habitat which is upland and cross to the pools and if you get a really big storm that’s over 40 in the spring, it’s incredible to be out that night. We call that “big night” and all the salamanders, the frogs, they’re all crossing into the pool. They’re all jumping all over you, they’re breeding and calling, it’s like a huge party. And it’s really, really cool to be out there. Unfortunately this year, the weather has been so weird because of climate change that we haven’t really had a “big night” we’ve had some little nights a bunch of little nights so I was just walking around this pool before we started filming and there are wood frogs in there which are an “obligate vernal pool species”, those are the ones that quack like ducks they go “Quack Quack” and they’re in there, they are what we call “explosive breeders”. They only breed for like a week and there are really actually fascinating animals because they can freeze solid in the winter. So they actually go off into the upland after they breed, they spend the summer eating and then in the fall they just go just underneath the leaf litter and they freeze solid. Their heart stops, their brain stops, everything stops. And in the spring they thaw out again and they’re perfectly okay. Scientists are actually studying them to see if they can replicate that in humans but so those wood frogs will come out breed and then leave so you only see them for about a week a year


Judy: Wow so I’m thinking like how wide around the vernal pool do you need to protect?


Kyla: That’s a good question and it’s something that politicians and regulators don’t like to talk about because, right now in Massachusetts, there’s a hundred foot buffer that (and there are exemptions from that) but basically you can protect up to a hundred feet around a vernal pool, but in actuality some of these animals will go up to a kilometer away, so if you build a road in between a vernal pool and the upland habitat…

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