I would like to thank everyone for coming to this presentation. Today I will be talking about the possibility of biotic factors altering the migration and breeding cycles of the Rough Skinned Newt.
The rough skinned Newts commonly head to breeding waters in early October triggered by the first rain of the season. Except for those species found along the Southern Oregon Coast. Why?
There are only two sub species of Rough skinned newt. The ssp Granulosa and Mazamae. There is still debate on weather or not Mazamae is a separate distinct species.
Rough Skinned newt is considered to be the most toxic amphibian in North America. Measured by the amount of mice killed by the secretion of tetrodotoxin(TTX), A non protein neurotoxin that block sodium channels of excitable membrane. One adult Newt secretions can kill 25,000 mice (or one university student).
Rough skinned newts prefer habitats that are along ponds and lakes and spend the non-aquatic phase of their lives in nearby forests.
Direction is governed by olfactory senses, humidity, a downward slope sense and there has been evidence of sun compass use.
When Males become into breeding season they will go from their rough skin to a more glossy appearance. Due to the fact that most breeding happens in or near water, a more glossy texture and mucus like membrane help protect the newt in the water and create a more streamlined body aiding in water movement.
There have been several reports done on the RSN but each one had a different result. The consensus of all the reports is that the stock found along the Southern Oregon Coast displays a “reverse” migration, but no one can figure out why.
The study was conducted along stretch of forest along eel lake at Tugman State Park located just out side Lakeside, Oregon
5 sample sites each one at different elevations but within 500 yards(approx) from lake access.
Population counts were at various locations with greater distances between them to avoid recapture. Each survey lasted approximately 1 hour in length and varied in tempature.
In October 2009 an blue green algae bloom advisory was continued in neighboring Ten Mile Lake and since there was no recent water survey done at eel lake. I conducted my own using an aquarium water test kit.
All the RSN were heading in the same south eastern direction and climbing in elevation. Away from the lake. No other large bodies of water were at the higher elevations.
Oddly; only one salamander (Oregon slender Salamander (BatrachosepsWrightorum))was found. It was found outside of the sampling area therefore not included in the study.
As shown in the graph the abundance of species were dependant on temperature with the exception of the beetle. The common Garter snake was omitted due to only one snake was found.
Based on previous studies The RSN and other members of the newt and salamander species should be heading towards the water. During a recent hike in the Oregon Dunes National recreation area at Hall/Shuttpelz Lake. RSN were found heading towards the lakes.
RSN require low to moderate ph levels and I testedthe Ph at 8.8 or greater.In October 2009 public health advisory was extended for neighboring Ten Mile Lakes.Garter snakes were almost non existent ( due to hibernation). They can only function in temperatures above 60° and the RSN were more active around the 55° range.
The summer water temperatures were lower this year. Normally RSN can be found along the lakes shores in large numbers but they were low this year.
Despite the simplicity of the study, many possibilities have been explored and the results show that biotic conditions exist and the RSN have been affected. It is my opinion that the change in migration is due to a combination of factors but the biggest factor is the absence of their natural predator.
Thank you for coming and have a nice day
Rough Skinned Newt By Raeth Morgan
By Raeth J. Morgan<br />Rough Skinned NewtTaricha Granulosa<br />
What are the factors that have changed the seasonal migration of the Southern Oregon stock.<br />Chemical composition of nearby breeding ponds?<br />Predator avoidance?<br />Dramatic climate change?<br />Goals of the study<br />
One of the most abundant Salamander species in the Pacific Northwest.<br />Only two subspecies exist. Ssp Granulosa and Mazamae (only found in Crater Lake, Oregon).<br />Often referred to as “Orange Bellied Newt” or “Oregon Newt”.<br />Two stages of life: Aquatic and Terrestrial.<br />What is a Rough skinned Newt?<br />
Adult size ranges from 3 ½” to 8” total length<br />Medium sized lunged salamander with dry granular skin with no coastal groves.<br />The most toxic Newt in North America. <br />What is a Rough skinned Newt?<br />
The rough skinned newts generally breed in every month except November.<br />Lower elevations: tend to breed February to May.<br />Higher elevations : breed late spring to early fall.<br />Mating generally occurs in the water.<br />Eggs are laid 5-10cm under the water surface.<br />Directed to breeding ponds by a built in directional “homing” sense.<br />Breeding: When where and why.<br />
Migration toward breeding waters triggered by first seasonal rains.<br />Temperatures : 60°-70°F summer, 40°-50°F<br />Require low to moderate Ph levels<br />Breeding: When where and why.<br />
Newt samples were collected along Eel Lake in Tugman State Park Oregon.<br />Collection Site<br />
EEL LAKE<br />William Tugman State Park, Oregon<br />
Large deep coastal lake located at the mouth of the Umpqua river.<br />Surface elevation: 16m.<br />Surface Area: 141 ha.<br />Volume 17,554,100 m(cubed)<br />Depth: 20.9 m<br />EEL Lake<br />
Population counts were conducted from October 2009 to November 2009.<br />Newts were caught by hand and lengths recorded.<br />Capture sites were ¼ in circumference and sites were ½ mile(approx) away from previous sites.<br />Methods<br />
In September 2001 DEQ found the lake to be anoxic at the deepest part.<br />In October 2009 Algae Bloom advisory<br />Water sample was taken in mid November 2009.<br />Ph levels greater than 8.8<br />Ammonia .50 ppm<br />Nitrate/Nitrite 0.0 ppm<br />EEL Lake<br />
The rough Skinned Newt was more active during temperatures ranging from 52°to 62°.<br />All sampled Newt species were heading away from breeding grounds.<br />None of sample were in “breeding” mode.<br />Migration<br />
High Ph levels.<br />Chemical run off from residential fertilizers.<br />Containments from recreational fishing.<br />Toxic algae blooms.<br />Predator avoidance. The Rough Skinned Newts have only one natural predator: The common Garter Snake.<br />Possible reasons for change in migration.<br />
Climate change.<br />Seasonal rains late in season.<br />Cooler temperatures earlier in season.<br />Drop in water level.<br />Possible anoxic conditions.<br />Possible reasons for change in migration.<br />
Study was preliminary in nature, Further more long term, in depth studies needed to narrow down possibilities.<br />Rough Skinned Newts are affected by biotic conditions.<br />Results show correlation between the absence of predators and Newt abundance.<br />Conclusion<br />