Habitat Restoration and Management

For much more Oregon Spotted Frog information and photos, click on this link to the OSF Species Fact page: Oregon Spotted Frog (Rana pretiosa)

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Although Southeast Meadow looks like a shallow marsh with no topographic variation, deeper areas are largely hidden under a floating mat of reed canary-grass. Breaking through and removing parts of this mat is a key element in restoring habitat to sustain Oregon Spotted Frog tadpoles through development and after metamorphosis. Other components of this trial effort include restoration of OSF egg-laying habitat and improving conditions for tadpole dispersal. (Photo by S. Nyman, May 28, 2014)

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Our water level monitoring site is located on an area of floating mat.  This year, the maximum  water depth above the mat measured at the gauge was about 14 inches. Water level data collected this year allows us to identify  areas of existing habitat suitable for OSF egg-laying and deeper areas where tadpoles can survive to metamorphosis, and to predict seasonal water depths achievable with habitat restoration. (Photo by S. Nyman, April 23, 2016)

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By July 8, 2016, Southeast Meadow was dry or nearly dry at the surface, an insufficient period for most Oregon Spotted Frog tadpoles to survive and metamorphose

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Removing the floating mat revealed persistent water underneath even in late summer. Without the floating mat, maximum water depth in 2016 would have been more than 24 inches. (August 12, 2016)

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Phase 1: Working with hand tools, including a string trimmer, mattocks, bow rake,  and cultivator, a pool slowly develops as the reed canary-grass is cut, thatch removed, and chunks of sod are pulled. (Photo  by S. Nyman, September 8, 2016)

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The  piles of sod, thatch, and mud will be dried and then the material removed from the wetland.(Photo by S. Nyman, September 22, 2016)

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The pool will encompass sites where Oregon Spotted Frog tadpoles were found this year 70-110 feet from the egg mass cluster. The PVC pipe and flag in right foreground above marks trap site #2, where tadpoles were found on May 28 and June 15. (Photo by S. Nyman, September 22, 2016)

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This is trap site #2 on July 8, when there was barely enough water to submerge the funnel trap openings and no larvae were captured. (Photo by S. Nyman, July 8, 2016)

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Work Party Action! (Photo by S. Nyman, September 24, 2016)

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Habitat Restoration Chic! (photo by Chris Brown, September 24, 2016)

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Work Party Satisfaction! (Left to right: Chris Brown, Vikki Jackson, Erin Donahue, Monique Brewer, and Lyn Jackson!) (Photo by S. Nyman, September 24, 2016)

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Submerged mats of fine roots and mud are raked out and piled for drying. Floating mats allow reed canary-grass to establish itself in deeper water than where it would otherwise thrive. A tightly interwoven mat of thick rhizomes and fine roots serves to trap sediment and exclude competing plant species. (Photo by S. Nyman, September 26, 2016)

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Reed canary-grass in the surrounding area has now been cut, defining the boundaries of the pool. (Photo by S. Nyman, September 28, 2016)

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Pockets of water between the reed canary-grass tussocks are revealed when thatch is removed. (Photo by S. Nyman, October 3, 2016)

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Each work day moves us closer to completion of Phase 1. Because the west side of the pool (right side of photo) is located at the edge of the floating mat and is connected to shallower water, we are also creating conditions suitable for OSF egg laying on this edge. (Photo by S. Nyman, October 6, 2016)

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Maintaining the restored pool is likely to require further efforts during the dry season in 2017 to remove any remaining submerged rhizome fragments and continued vigilance to combat encroachment around the edges by reed canary-grass. However, water should be sufficiently deep in spring to early summer to impede the growth and establishment of this invasive species. (Photo by S. Nyman, October 6, 2016)

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Large piles of cut reed canary-grass and excavated root mat along the shorelines of the restored pool are ready to be moved. (Photo by S. Nyman, October 12, 2016)

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The spoil piles were no match for our army of work party volunteers! (Photo by S. Nyman, October 22, 2016)

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Volunteers followed prescribed paths while dragging tarps and sleds full of this heavy debris, thereby flattening and submerging the grass so that it will begin to decay.  Reducing excess thatch by mowing, raking, or accelerating decay should temporarily increase available aquatic habitat and facilitate dispersal of tadpoles from egg laying sites in 2017. (Photo by S. Nyman, October 22, 2016)

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The edges of the pool being cleared by the work party volunteers will provide areas of shallow, warmer water favored by developing OSF tadpoles. (Photo by S. Nyman, October 22, 2016)

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The results of our last work party will include more diverse habitats that are connected to support the complex life cycle of the Oregon Spotted Frog. (Photo by S. Nyman, October 22, 2016)

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Out WCAMP-WLT work party included 14 hard-working participants and satisfied smiles at the end of  the day. (Photo by S. Nyman, October 22, 2016)

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A final salute to our frog friends! (Photo by S. Nyman, October 22, 2016)

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The project also includes improving conditions in an existing pool where most of the OSF bred in 2013, 2014, and 2015, and where all of the frogs bred this year. One of the egg mass clusters from 2014 is marked by a pink flag in an area subsequently filled by dense grass (left center of photo) and one of the clusters in 2015 is marked by a flag at the far end of the remaining pool. (Photo by S. Nyman,  March 16, 2015)

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This is the same breeding pool after reed canary-grass has been cut, some of the large tussocks removed, and excess thatch raked out. The six pink flags mark most of the egg mass cluster locations from 2013 to 2016. (Photo by S. Nyman, November 3, 2016)

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The existing breeding pool and the new, restored pool are connected by paths cleared of excess thatch (i.e., deeper water than previously), which should facilitate dispersal (and thereby, greater survival) of larvae in 2017. (Photo by S. Nyman, November 8, 2016)

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Now we wait to see how the frogs and all of the other animals and plants that share this ecosystem will respond to the habitat changes we have initiated. Please stay tuned and stay involved!  (Photo by S. Nyman, November 11 2016)