Ten Tips to Give Frogs a Landing Pad

Creating a small wetland is easier than you think and can go a long way to help struggling amphibians and other wildlife

03-12-2015 // Anne Bolen

A wetland for wildlife at Mill Creek Elementary

FROGS ARE VITAL TO THE FOOD WEB, serving as natural bug zappers and as food for many predators, from raptors to raccoons. They are also important bioindicators that help us determine the health of our environment,” says Kerry Kriger, founder of Save The Frogs, an NWF partner. “We have a lot to learn from them.”

Indeed, about a third of the world’s some 7,000 amphibian species are at risk of extinction, struggling to combat pesticides, pollution, diseases such as deadly chytrid funguses, competition with introduced species and, in particular, habitat decline. One 2014 paper by the Institute for Land, Water and Society published in Marine and Freshwater Research estimates that at least 64 percent of the world’s wetlands—vital for amphibian breeding and feeding—have disappeared since 1900, overtaken by agriculture and development.

The good news is that amphibians can benefit immensely from us restoring or creating even small sources of water. So Save The Frogs has launched an effort to “Re-Frog America” one wetland at a time, encouraging landowners, schools and others to build 1,000 wetlands in a decade. Working with wetlands ecologist Tom Biebighauser, the organization has helped build more than a dozen wetlands in California so far, a state now in its fourth year of historically unprecedented drought and where small ponds and wetlands are drying up even before tadpoles can grow into frogs. 

Celebrate Save the Frogs Day on April 25 by organizing or attending an event or better yet, get your friends and family together and host your own wetland-building party. “You don’t have to be an engineer to build a wetland,” assures Biebighauser, who has helped create 1,700 of them in three countries. And if properly built, he says, “they can last for hundreds of years. There are very few things in life that last that long.”

Build a Small Wildlife Sanctuary

Here are 10 tips from Save The Frogs and Biebighauser for how to build a wetland (see also slideshow below) that will welcome amphibians and other wildlife for years to come.

1. Find dry, flat ground.

Survey your property for an area that is best suited for a wetland. The area should be relatively flat, with a slope of less than 6 percent, as steeper ground will lead to an unnatural looking wetland. You can measure your slope with a clinometer or download a clinometer app to your smartphone.

Measure out the area where you plan to dig. Before you start digging, however, check with the local municipality to see if any permits are needed and call 811 to check for buried utilities.

2. Determine what kind of wetland you wish to build.

California red-legged frogAlthough you can build a pond or wetland that will retain water year-round, ephemeral wetlands or vernal ponds, which retain water only a portion of the year, provide critical breeding sites to the rarest amphibians across the rest of North America.

In western environments, such wetlands are well suited for amphibians that are adapted to naturally dry climes, such as California red-legged frogs (right). These frogs metamorphose from tadpoles into adults fairly quickly, within about seven months, before making their journey to larger breeding sites. Such seasonal water sources also prevent bullfrogs, which are not native to California and can take up to two years in water to mature, from outcompeting the state’s native frogs. 

3. Decide how your wetland will retain water.

To retain water in a wetland, you can: rely on preexisting ground water that fills the hole you dig naturally, use high-clay soil that you then compact to retain surface water much like a bowl or use an aquatic-safe plastic liner.

To determine whether you can rely on groundwater, dig a hole at least 3 feet deep and cover it with a board. If the next day your hole is filled with water, you’ll be able to build your wetland simply by expanding the hole into a wetland. 

If no water fills your test hole, grab a handful of soil that is underneath the topsoil and add water. Mix the soil and water until it is a moist ball, then use your thumb and index finger to squeeze out a thin ribbon of soil. If you succeed in making a 2-inch ribbon, then you can compact the clay, which will make the soil impervious and enable it to fill when the next rains come. If the soil breaks before 2 inches in length, it does not have enough clay for it to hold water and you’ll need to use a plastic liner.

4. Dig a shallow hole.

To encourage the most plant and animal diversity, aim for water depths of 18 inches or less. Any deeper may attract fish and other amphibian predators. To create natural wetlands that require little to no maintenance, gradually slope the soil 5 percent or less around your wetland.

5. Use a plastic liner that is safe for aquatic wildlife.

Only purchase a guaranteed aquatic-safe, fish-grade liner that comes from a reputable source. All others are likely treated with pesticides toxic to wildlife.

Once you dig your hole, place the liner and anchor the top edge of it with 12-inch landscape spikes, placed every 18 inches around the perimeter. This will prevent the liner from sliding into the center of your hole and allow it to hold water. Next, cover it with at least 6 inches of soil, which will provide a natural floor for your wetland.

6. Provide natural ladders, cover and shade.

Unless you have very muddy water (which may be an indication that fish have moved in) or actually spot fish in your pond, don’t clear away leaves or woody debris. Wildlife prefer a messy wetland. After all, small creatures need shade and a place to hide from predators. So create numerous mounds of soil varying in elevations, some that emerge out of the water, and add dead logs, large branches and twigs, which will provide shelter and serve as ladders for small animals to get safely in and out the water. 

7. Surround the wetland with native plants.

Spreading clean wheat straw and planting native plants around the edge of the new wetland will prevent erosion and help exclude invasive species. The straw also helps prevent algal growth. The plants will draw insects that will benefit the garden and feed your growing amphibian population. For tips on how to Garden for Wildlife™, visit www.nwf.org/nwfgarden.

8. Don’t use pesticides or weed killers.

Amphibians absorb water—and any chemicals in it—through their skin. Chemicals in certain pesticides have been known to cause deformities, disrupt hormones and interfere with reproduction in frogs. So avoid using any pesticides, herbicides or fertilizers near your wetland.​​​

9. Don’t add fish or transport frogs to your pond or wetland.

Fish and nonnative frogs or other amphibians can outcompete natives for food and habitat. Plus, they can carry chytrid, a deadly fungus, and other diseases. Native frogs will find your wetland in their own time, so let nature take its course and don’t stock your pond.

10. Consult experts.

Having the experience of a wetlands construction expert can ensure your design will be wildlife-friendly. To find a wetland training workshop near you, visit Tom Biebighauser’s website at www.wetlandrestorationandtraining.com or Save The Frogs.

To find out more about Save The Frogs Day events and helping amphibians, go to www.savethefrogs.com.


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