Woodland Fish & Wildlife • 2017 Amphibians in Managed Woodlands Tools for Family Forestland Owners Authors: Lauren Grand, OSU Extension, Ken Bevis, Washington Department of Natural Resources Edited by: Fran Cafferata Coe, Cafferata Consulting Pacific Tree (chorus) Frog Introduction good indicators of habitat quality (e.g., Amphibians are among the most ancient habitat diversity, habitat connectivity, water vertebrate fauna on earth. They occur on all quality). Amphibians also play a key role in continents, except Antarctica, and display a food webs and nutrient cycling as they are dazzling array of shapes, sizes and adapta- both prey (eaten by fish, mammals, birds, tions to local conditions. There are 32 species and reptiles) and predators (eating insects, of amphibians found in Oregon and Wash- snails, slugs, worms, and in some cases, ington. Many are strongly associated with small mammals). The presence of forest freshwater habitats, such as rivers, streams, salamanders has also been positively cor- wetlands, and artificial ponds. While most related to soil building processes (Best and amphibians spend at least part of their life- Welsh 2014). cycle in water, some species are fully terres- Landowners can promote amphib- trial, spending their entire life-cycle on land ian habitat on their property to improve or in the ground, generally utilizing moist overall ecosystem health and to support areas within forests (Corkran and Thoms the species themselves, many of which 2006, Leonard et. al 1993). have declining or threatened populations. The following sections of this publica- Photo by Kelly McAllister. Amphibians are of great ecological impor- tance and can be found in all forest age tion describe amphibian habitats, which classes. Many amphibian species utilize both amphibian species are found in Oregon and Washington, common threats, and habitat Though amphibians and rep- aquatic and upland habitats throughout their recommended enhancement techniques. tiles regulate their body tem- life-cycle, therefore, they are considered perature by their surroundings Example of Amphibian Habitat and can look alike, they are distinct groups of animals. Reptiles have thick, dry and scaly skin, and are often found in warm, dry places though some forage near water. Am- phibians have thin, moist skin and are found in cool, moist areas. Reptiles lay their eggs on land, usually in warm, dry places. Amphibians generally lay their eggs in water or in moist habitats. Frogs, toads, salamanders and newts are amphibians. Reptiles include snakes, lizards and turtles. Photo by Lauren Grand. 1 Woodland Fish & Wildlife • 2017 ponds, sloughs, marshes, swamps, Northwestern Salamander bogs, fens, floodplains, riparian Large, heavy-bodied with smooth brown moist skin. Can reach nearly fringes, ditches, fire ponds, irrigation 10 inches in total length. Photo by Jessica Homyack. ponds and storm water ponds. Having a variety of wetlands on the landscape is important to maintaining amphibian diversity because some species need wetlands that are present year-round while other species rely on seasonal wetlands to avoid predators. West- slope, low elevation, seasonal wetland ponds often have the highest diversity of amphibian species because of an absence of competitive and predatory fish, and minimal numbers of other predators such as the non-native inva- sive American bullfrog. Most amphibians prefer shallow wetlands with gently sloping sides, a range of water depths, and little to no current (less than 15 cubic feet/second). Emergent and Amphibian Habitats riparian vegetation provides good habitat, Long-toed Salamander Amphibians are truly unique because they adding oxygen to the water, provides egg- not only require water or moist habitats Named for the exceptionally laying substrate / egg mass attachment for breeding, but most of them migrate to long fourth toe of the hind sites, and allows larvae to forage and seek forests and other terrestrial (upland) areas foot. Smooth brown skin cover. Some species require the emer- for the rest of the year. For example, ter- with green/yellow stripe down gent vegetation to be submerged at least restrial salamanders, such as the Ensatina the back. Approximately 6 2-3 feet deep to minimize the risk of the and Dunn’s Salamander, do not have inches in total length. Photo wetland drying out before eggs hatch and lungs, but exchange oxygen through their by Lauren Grand. juveniles disperse. Diverse native emer- skin (Corkran and Thoms 2006). Rough- gent vegetation also provides habitat for skinned newts and western toads utilize a wide array of insects for amphibians to still and open waterbodies for breeding eat. Many amphibians need sun exposure and egg laying, but spend most of the for successful reproduction. When direct year under logs, underground, and in leaf sunlight can reach over 60% of the pond’s litter foraging and hiding from potential edge the larvae grow and develop into predators. healthier adults. Sunlight, with the help of wind breaks, will encourage a warm Except for fully terrestrial amphibians, microclimate and a healthy amount of breeding habitat takes the form of either floating aquatic vegetation such as native standing water in wetlands, or the moving duck weed which cools water and increas- water found in streams. Both permanent es oxygen and food for larvae. Basking and seasonal wetlands are used for egg- sites that protrude out of the open water laying. Most terrestrial salamanders lay such as logs, rocks, floating vegetation, their eggs in decaying logs and seeps next and fallen limbs are great habitat features to streams. Key habitats for amphibians that add complexity to the wetland and are described below. benefit a variety of species. While veg- Aquatic Habitat etated buffers around wetlands are highly beneficial, too much shading can make Many Oregon and Washington frogs the pond less suitable for some amphib- and salamanders lay their eggs in still ian species. or slow-moving water. Aquatic habi- tats used include wetlands, including 2 Woodland Fish & Wildlife • 2017 Tiger Salamander Large, heavy-bodied with smooth brown moist skin and small protruding eyes. Can reach nearly 13 inches long in total length. Photo by Chris Loggers. A specialized group, the tailed frogs, giant Forests are often the preferred upland drought. Forests have the potential to salamanders, and torrent salamanders, habitat for migrating amphibians because provide a moderately dense, but diverse only lay their eggs in streams or seeps. forested canopies provide an abundance understory structure of forbs, grasses, and These amphibians prefer cold turbulent of shade, moisture, and cool temperatures shrubs that create microhabitats frequent- streams that are 3 – 9 feet wide, with a that amphibians need to thrive. Forests ly used by amphibians. Amphibians take variety of pools separated by stretches are also rich in water features (including advantage of falling leaves and aerated of faster moving water (riffles) or steep forested wetlands, seeps, and streams) soils by burrowing under loose soil, deep plunging water (cascades). Streams with that amphibians use to stay moist while leaf litter, and moss for cover. They will these characteristics often are headwater moving through the landscape. also take advantage of rodent burrows streams, and may be found in areas with Adequate cover (such as down logs, slash during the heat of the day, or to hibernate steep valley walls and rocky faces. Tailed piles and leaf litter) in the upland habitat during freezing winter months. Rotting frogs, giant salamanders and torrent sala- not only provides amphibians with places wood in the form of large logs, fallen limbs, manders prefer these cold and clear water to hide and find food, but also minimizes loose bark, stumps, or woody piles provide habitats (with silt being quickly washed fluctuations in temperature and mois- moisture, shelter, movement corridors, downstream) that contain high amounts ture to which amphibians are extremely and many invertebrates for food. Large of oxygen due to the mixing of turbulent sensitive. This prevents amphibians from standing dead legacy trees provide valuable water with the air. High and brushy, over-stressing or drying out during the habitat for the Pacific tree frog and some riparian vegetation with deep litter on warm summer months and periods of salamanders such as the clouded salaman- the forest floor increases relative humid- der that are adapted to climbing. Rocks, ity and provides habitat for the insects rock piles, and talus also provide habitat that these amphibians prey upon. Ideal Rough-skinned Newt that is essential for many amphibian spe- stream habitats for these species also have Dry granular skin brown above cies such as the Del Norte and Larch Moun- streambeds with deep cobble and small and bright orange below. Skin tain salamander. All of these structures can boulder substrates and an abundance of is toxic if ingested. Can reach be used for various life activities including large wood in streams that creates pools. nearly 8 inches in total length. shelter from predators or inclement and This complex habitat allows for both Photo by Kelly McAllister extreme weather, cavities for hibernat- foraging and hiding. Giant salamanders ing, and hunting. Downed wood and rock usually forage in pools, while tailed frogs structures eventually develop small under- are found in riffles and cascades. Torrent ground cavities for salamanders to burrow salamanders usually hide in the splash in