by: John Gilhen
WINTER 1991
Working here at the Nova Scotia Museum I receive public inquiries every day. Over the past several years some inquiries have come from concerned adults who grew up in suburban areas of Halifax. they want to know why there are no more frogs in their area.
Since about the 1960s there has been rapid development beyond our city limits. It began with new roads radiating from main highways and gradually houses began to spring up. Young people growing up in the 1970s and early 1980s collected tadpoles in ponds along the roadside and in gravel pits. They heard northern spring peepers vocalizing during spring nights. Today apartment buildings and shopping centres are in their place. The ponds are gone and so are the frogs. Adults tell their children, "When I was your age we used to collect tadpoles in a pond where that parking lot is".
Amphibian populations tend to benefit during the early stages of development. The roadside and gravel pit ponds provide excellent breeding habitat. Some species even overpopulate. However, automobiles and children keep the populations in check most of the time. Once you get away from populated areas and into the wilder areas of Nova Scotia amphibian populations seem to be doing just fine. There are some who would disagree with me.
In the 1950s if someone found a mink frog in Nova Scotia it was considered to be a major find. This species until recent years was though to be most uncommon in this province. Last summer I visited a small lake north of Upper Musquodoboit in Halifax County. I noticed a large number of small green frogs jumping into the shallows. I soon realized these were young mink frogs. I could have collected 100 of these frogs in a short time along 20 metres of lake shore. does this mean mink frogs are on the increase in Nova Scotia?
Not long ago I talked with a young naturalist who worked this past spring for the Department of Lands and Forestry in the Lake Rossignol area of Queens County. I asked her if she saw any frogs there. She said there were a lot of frogs. In fact, pickerel frogs were just-a-hoppin' there this spring. Does this mean pickerel frogs are on the increase in Nova Scotia?
The answer is, of course not. A lot of new roads have been built through Nova Scotia in the past 25 years. This opened up vast areas of the province allowing herpetologists the opportunity to make their observations and give us a better understanding of species distribution.
Another problem exists in Nova Scotia. During the past 25 years smallmouth bass have been widely introduced in lakes on the mainland. This fish preys upon amphibians and may contribute to the slight decline of some species in these areas.
What I have noticed during the past 10 years or so, during the later stages of community development, is the isolation of ponds and small woodlots. Confined to these isolated habitats there is great potential for inbreeding. Hence the discovery of albino eastern redback salamanders, green frogs and leopard frogs.
The fact of the matter is, amphibian populations tend to fluctuate from year to year, sometimes quite dramatically. every puddle and pond has a history and you can't determine population trends after two visits in one season. What we need is long-term observations of these ponds and the amphibians which inhabit them. If you have information, and/or are concerned about the status of frog populations in your area, refer to contacts below.