Efforts to enhance Oregon spotted frog habitat includes new method for invasive species resistance

Oregon spotted frog egg massOne of the harbingers of spring is in the act!  Even before the calendar registered spring, our native amphibians were excitedly welcoming the warm weather and longer days.  Red-legged frogs, Pacific chorus frogs, and our federally threatened Oregon spotted frog were all breeding at Mima Creek Preserve this spring.  After searching through the seasonally inundated sections of the preserve, through dozens of red-legged frog egg masses, the Oregon spotted frog egg masses were discovered by honing in on their distinctive breeding call - knock, knock, knock, knock.  Oregon spotted frogs lay eggs together in shallow seasonally inundated fields, which historically were wet prairies or meadows.  Much of this habitat type has been lost to agriculture, development and invasive species.  Annual mowing to keep the vegetation low at Mima Creek has encouraged the frogs to continue laying eggs there, however this intensive mechanical method does not actually restore habitat for the frogs.

Efforts to permanently remove reed canary grass and restore native species are underway: we are evaluating the impacts of solarization (effectively ‘cooking’ the plants, roots and seeds of reed canarygrass by securing large sheets of plastic over recently mowed areas during the hot summer months) and placing biodegradable coconut fiber mats pre-planted with native vegetation into treated areas. We have partnered with the Sustainability in Prisons Project to grow the mats (see their latest blog post on this project at: in a state-of-the-art aquaponics facility. The mats will have a suite of healthy native sedges already established in them when they are placed out into the treated areas next fall, providing a leg-up when it comes to establishment and invasive resistance.  We hope this technique will work to remove invasive species and establish low-maintenance native habitat for the Oregon spotted frog and other native wetland species.