Friday, June 9, 2017

Pacific Giant Salamander at Prairie Creek Redwoods State Park

Recently, Eric and I spent several days camping and hiking in the redwood forests of Northern California, visiting Prairie Creek Redwoods, Grizzly Creek Redwoods and Patrick's Point State Parks.  In four days, we hiked just over thirty miles of absolutely stunning terrain, always alert for interesting flora and fauna.  The temperatures were cool and ideal for hiking, the forest wildflowers were in bloom, and the birds were not entirely uncooperative: in the depths of night, a pair of Barred Owls caterwauled for a solid 45 minutes from the redwoods above our tent, and many other diurnal species enchanted us with their songs.  Very few birds actually showed themselves, though, instead remaining hidden in the dense verdant undergrowth and high above in the redwood canopy.  Quick glimpses of thrushes and warblers were all we were allowed.  The gulls at Gold Bluffs Beach were obliging, as they typically are, and I was excited to spot a very far-off flock of Pacific Loons rafting beyond the surf.  The Roosevelt Elk, for which Prairie Creek Redwoods is famous, were bold and unconcerned by the presence of gawking tourists. 

But the most exciting discovery I made during our explorations was that of a humble salamander.

But this is not just any salamander: this is the Pacific Giant Salamander (Dicamptodon tenebrosus), the largest terrestrial salamander in North America.  One may wonder why finding a salamander was so exciting for me, as a naturalist whose interests more commonly lie in plants, birds and mammals.   At the most basic level, I was excited because not everyone who visits the redwoods gets to see a salamander.  The redwoods are a given sight for anyone driving highway 101; the wildflowers bloom in predictable seasons.  The elk are almost guaranteed to be seen at Elk Meadow and Elk Prairie.  And the birds of the redwoods, while elusive, make themselves known through song.  But it's not every day one gets the privilege of observing a salamander!

Pacific Giant Salamanders measure from 7 to 11 inches long, their bodies mottled browns and grays to perfectly blend in with the damp forest floor.  Salamanders are amphibians, and as such their reproduction depends on water.  Adults are terrestrial, though never far from rivers and their tributaries.  Terrestrial adults spend their days hidden in damp retreats beneath logs, rocks and leaf litter on the forest floor.  They emerge to forage most commonly during rainy nights, though the overcast and foggy days which grace California's northwest coast favor some diurnal activity. 

Pacific Giant Salamanders, recently earning distinct species-hood after being separated from the similar California Giant Salamander (D. ensatus), inhabit cool, humid forests of California's North Coast Range, north of the Gualala River in Mendocino County.  Their range extends north to the border of Washington and British Columbia.   (California Salamanders are found in similar habitat from approximately the northern border of Sonoma county south through Santa Cruz county.) 

After spring breeding has occurred in clear streams, larvae of the Pacific Giant Salamander hatch in late fall or winter.  Larvae metamorphose into adult salamanders during the second summer after hatching.  Pacific Giant Salamanders feed on insects and other invertebrates (like Banana Slugs) as well as small snakes, lizards, other salamanders and rodents.  Prey is hunted by the sit-and-wait approach, the salamander sitting quietly before lunging out to capture whatever happens by.  They are not particular, provided the prey item can fit in the salamander's mouth! 

Pacific Giant Salamanders rely on clear, shallow water for reproduction.  Clear-cut logging and the erosion that follows severely degrades this habitat by allowing previously clear streams to become silted, or filled with sediment.  Though there is no official protection for this salamander, it luckily shares habitat with Steelhead Rainbow Trout (Oncorhynchus mykiss) and Coho Salmon (O. kisutch), two species of considerable concern.  The creeks in which these two endangered fish species breed are protected, and as a result, salamander habitat is also preserved.

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