Rough-Skinned Newt
Source: www.stockpix.com/stock/animals/reptilesandamphibians/
amphibians/salamanders/1360s4.jpg
Long-toed Salamander
Source: courses.washington.edu/vertebra/451/photos/amphibian/
longtoed_toes.jpg
Pacific Tree Frog
Source: http://library.thinkquest.org/17456/amphibiansall.html
Bullfrog
Source: Tom Tyning http://www.mainerivers.org/species/bullfrog.htm
Amphibians
The data collected in this study is the first step in the multi-year process of restoration. It will provide a baseline for future monitoring efforts at the Delta Ponds. From our work the clients will have a thorough understanding of the health, abundance, and locations of amphibian species at the ponds and their prime areas of habitat. They can then refine the restoration work according to our findings, concentrating efforts in certain areas, and avoided construction in areas designated as critical habitat. Four key species and one species of interest are included in our amphibian surveys.
Rough skinned newt ( Taricha granulosa )
Why is the rough skinned newt a key species?
The Delta Ponds are critical habitat for rough skinned newts that require a damp and cold environment for thermoregulation and to keep its permeable skin moist. It is important to track its abundance because this species is often an indicator for the health of the system in which it is found.
What does a rough skinned newt look like?
The rough-skinned newt's distinct appearance makes it easily recognizable. It ranges from light to dark brown with bright orange to yellow coloration on its ventral, or bottom, side. It is a fairly large species, ranging from five to seven inches as an adult. Its skin is very granular and not slimy to the touch.
What are the threats to rough skinned newts in the Delta Ponds area?
Health threats for the rough-skinned newt population at the Delta Ponds are centered on habitat destruction. While in the aquatic larval stage, this species needs cold temperatures and oxygen in the water. However, oxygen content is inhibited by algal growth and low connectivity between ponds, which replenishes the oxygen supply and maintains low water temperatures. Predatory species include the bullfrog, and multiple garter snake species, which prey on egg masses and larvae, as well as adults.
What are the monitoring methods used to find rough skinned newts at Delta Ponds?
We will use a sampling technique involving artificial cover objects (ACO's). In our study we use plywood pieces placed at designated sites around the ponds in order to create microenvironments for salamanders to inhabit. The presence and abundance of salamanders at these sites will provide an estimate of the size of the overall population.
What are the results of rough skinned newts surveys at Delta Ponds?
This data has not been collected yet. Stay tuned!
Northwestern salamander ( Ambystoma gracile )
Why is the Northwestern salamander a key species?
As a native amphibian this species is important in gauging the effects of development and global warming in the region. Amphibians are often the firsts to bear the effects of human population growth and development, as their health is dependent upon the health of their habitat.
What does a Northwestern salamander look like?
The northwestern salamander is large is size, reaching up to 22 cm in length. They are very dark in color, from brown or gray to black dorsally and lighter brown on its ventral side. The presences of conspicuous glands along the ridge of its tail and at the rear of its head are characteristics that make it distinct among other salamanders. The concentrations of granular glands make up the tail ridge, while large paratoid glands sit just behind the eyes on its head. Another specialized characteristic of the species is a large head with small eyes.
What are the threats to Northwestern salamanders in the Delta Ponds area?
Multiple studies have found there to be less species abundance in young forests, as opposed to old-growth stands. It is also speculated that the effects of global warming and increased aridity will reduce breeding habitat and lead to decreased survival. Thus the quality of the habitat at Delta Ponds is critical to maintaining a population of Northwestern salamanders there
What are the monitoring methods used to find Northwestern salamanders at Delta Ponds?
We will use a sampling technique involving artificial cover objects (ACO's). In our study we use plywood pieces placed at designated sites around the ponds in order to create microenvironments for salamanders to inhabit. The presence and abundance of salamanders at these sites will provide an estimate of the size of the overall population.
What are the results of Northwestern salamander surveys at Delta Ponds?
This data has not been collected yet. Stay tuned!
Red-legged frog ( Rana aurora )
Why is the red-legged frog a key species?
The red-legged frog is also native to the Pacific Northwest, ranging from southwestern British Columbia to northern California in coastal areas west of the Cascades Mountains.
Everywhere within their range this species is on the decline. Conservation efforts are very important as its abundance continues to decrease and habitats are in a critical state of need.
What does a red-legged frog look like?
They are medium-sized with smooth brown to reddish skin marked with black "freckles". Male frogs can reach up to 7 cm while females, the larger of the two, can reach up to 10 cm in length. Red-legged frogs usually have a dark "mask" running across their eyes and the sides of their head, as well as a light upper jaw stripe that runs back to the shoulder. The distinctive reddish coloration of the ventral legs and belly is what gives this species its name.
What are the threats to the red-legged frog at Delta Ponds?
There is great concern over the status of red-legged frogs. The species is officially listed as threatened by the Fish and Wildlife Service due to population declines resulting from over-harvesting for its prized frog legs. Red-legged frogs are no longer harvested for their legs but other threats such as human development of their habitat and predation by non-native bullfrogs continue to be a problem in the Delta Ponds area.
What are the monitoring methods used to find red-legged frogs at Delta Ponds?
We will monitor the presence of its egg masses throughout the ponds in order to get an estimate of the species population. This enables us to avoid the troublesome task of catching a representative sample of this sometimes rare and reclusive species. The egg masses can be seen attached to vegetation at the surface of the ponds. Using boats to search the banks of the ponds the location of each egg mass and its condition is recorded.
What are the results from looking for red-legged frog egg masses at Delta Ponds?
Although we have found no egg masses as yet one more survey is planned.
Pacific tree frog ( Hyla regilla )
Why is the Pacific tree frog a key species?
Despite their small size, the Pacific tree frog is important to the area. It is native to the Pacific Northwest and its abundance around the Delta Ponds will provide an indicator for the general health of the area.
What does a Pacific tree frog look like?
They grow to only 5 cm long and vary greatly in their coloration, appearing anywhere from tan or gray to bronze or bright emerald green. Its dark "mask," extending from its nostril, across the eye, and back as far as the shoulder distinguishes it from other species. Other markings include dark patches or stripes on the back and pale underneath. The Pacific tree frog has round pads on its toes with little webbing, allowing it to attach and climb structures with great agility.
What are the threats to Pacific treefrogs in the Delta Ponds area?
However, it faces the same threats as all other amphibian species in global warming, pollution, and increased development infringing upon habitat.
What are the monitoring methods used to find Pacific treefrogs at Delta Ponds?
We will be using vocalization surveys to determine the size of the Pacific tree frog population at Delta Ponds. A listening route is established around the ponds and listening posts are designated where vocalizations can be heard. Although only the males in the population make vocalizations, this method provides an estimate of its overall size.
What are the results of listening for Pacific treefrogs at Delta Ponds?
Although there is a symphony of Pacific treefrogs at Delta Ponds this data has not yet been analyzed. Stay tuned!
Bullfrog (Rana catesbeiana)
Why are bullfrogs a species of interest at Delta Ponds?
Bullfrogs are an invasive and highly predatory species that will eat other frogs, turtles and crustaceans. They are known to eat young western pond turtles and are considered a significant threat to the species. They also compete with the native Pacific tree frog and threatened red-legged frog for resources and may prey on them as well. Bullfrogs are considered a noxious invasive species at the Delta Ponds.
What does a bullfrog look like?
Bullfrogs grow up to six inches long and typically have a greenish or brownish coloration on their dorsal side, and a cream to yellow coloration on the ventral side. They have an exposed eardrum, known as a tympanum, behind each eye. This membrane is smaller than the eye in females and larger than the eye in males. Male frogs emit a deep rumbling call to attract females, and possibly to claim territory, which it physically defends from other males.
What are the monitoring methods used to find bullfrogs at Delta Ponds?
We will be using vocalization surveys to determine the size of the bullfrog population at Delta Ponds. A listening route is established around the ponds and listening posts are designated where vocalizations can be heard. This method provides an estimate of the size of the bullfrog population.
What are the results of listening for bullfrogs at Delta Ponds?
This data is not in yet. Stay tuned, and please see our Events page if you are interested in helping with bullfrog vocalization surveys!
For more information on the amphibians at Delta Ponds please see:
Bruening, S. 2002. "Rana catesbeiana" (On-line), Animal Diversity Web. Accessed February 02, 2005 http://animaldiversity.ummz.umich.edu/site/accounts/information/Rana_catesbeiana.html
Brown, S. 2000. "Rana aurora" (On-line), Animal Diversity Web. Accessed February 15, 2005 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Rana_aurora.html .
Introduced Species Summary Project: North American Bullfrog (Rana Castesbeiana). Martin Murphy, Feb. 17 2003. http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Rana_catesbeiana.htm
Pacifc Tree Frog . 8 Feb. 2005. http://wlapwww.gov.bc.ca/wld/frogwatch/whoswho/factshts/pactree.htm
Red Legged Frog . 8 Feb. 2005 http://wlapwww.gov.bc.ca/wld/frogwatch/whoswho/factshts/redleg.htm
Romansic, John. Ambystoma gracile . Ed. Duncan Parks and Meredith J. Mahoney. 8 Feb. 2005 F d ½ > j @@j @ > j ’$I’$I0@~ > j @ > j UUUUUU)@~ > @ý ? y l ? j UUUUUÕ<@½ $ ? j @j X¦@j @j Ü©@ @ ý @ F e @ j ²…,d!>@~ @ j 7@ @ j ÑE]t=@½ @ j 7@j B@ 6@ × < " ž ` \ j * Ä s