my backyard pacific chorus frogs
Hello! I am trying to maintain a population of pacific chorus frogs in my neighborhood that had been breeding in an neighbor's neglected swimming pool. The pool and property were destroyed this summer. Many of the frogs are hibernating in my yard. I bought a pool 3 feet deep and about 4' by 6' foot to collect rain water for a breeding ground for them. It has filled with rainwater and figs that fell from my fig tree. Will the decaying figs be bad for the water quality for the tadpoles in spring? Or would the decaying figs (and leaves) be good? The water is very cloudy. Is there a way to make sure the water quality is right for the eggs/tadpoles/froglets as well as for potential pond plants?
Thank you for submitting your questions to OSU Extension! I'm happy to answer your question to the extent I am able to.
The Pacific Chorus Frog (Pseudacris regilla), also known as the Pacific Treefrog, is a widely distributed species in western Oregon and does not appear to be under a sigificant threat to its population (it's not on any species of concern, threatened or endangered list).
It's published habitat needs appear to be in line with what you are experiencing in your neighbor's abandoned swimming pool. They seem to do fine in temporary wet areas (low-lying wet areas, depressions, ditches, pools, ponds, etc.). Size doesn't appear to be a limiting factor to them, as you've seen first hand. They do breed in these small wetland features, which likely improves their chances of survival and minimizes impacts to their populations.
Risks to their populations do exist. Certain predators can impact local populations. Multnomah County, as well as throughout the Oregon coast and Willamette Valley, is home to an invasive frog species, the Bullfrog (Lithobates catesbeiana), an aggressive species that feeds on all sorts of aquatic animals, including the eggs, tadpoles and adults of smaller frogs. Raccoons are also common predators to frogs, but likely have less of an impact relative to the bullfrog.
In terms of providing habitat, nothing beats the wetlands naturally occurring in your area, and habitat conservation efforts are key to any species long-term survival. The more rough, un-manicured places you have on your property (and by extension in the neighborhood) with places to hide, find food and water, the more conducive are the conditions for tree frogs and other wildlife. However, if you wish to provide wet areas for this species, your swimming pool might be a suitable replacement. I can't speak to the issue of water quality as it relates to the presence of figs in the water, but in general, I'd recommend removing as many as you can. Leaves and twigs are probably not an issue. Fruit steeped in such a small pool might alter the pH of the water, thus affecting the survival of eggs and tadpoles, although again, I can't say for certain and I'm only speculating. Generally speaking, the water shouldn't need to be kept immaculately clean. Give it a try this winter and see how it goes. My guess is that since they seem to be doing well in your neighbor's neglected pool, they should do fine assuming they choose your pool.
Other thoughts about the pool: Providing some source of cover (leaves, sticks, rocks) wouldn't hurt. These items also provide a place upon and within which the adults can lay their eggs. Also, put some sticks, large branches, or rocks in such a way that the frogs can get out of the pool when needed. If the pool has steep plastic sides, the frogs may have problems climbing out. They also provide a place to perch when they're not in the water.
Here are a few web sites you might check out to learn more about the Pacific (Chorus) Treefrog:
Jason O'Brien - OSU Forestry and Natural Resources Extension - Coordinator, Oregon Master Naturalist Program