Figuring Out The Arboreal Salamander in Southern California

Given that it is located in the dry American West, California has a surprisingly high diversity of salamander species. In fact, California is one of the greatest salamander diversity hot spots in the world outside of the Eastern United States. Many of the species and genera found in California are also endemic to the California Floristic Province, from obscure species such as the Mount Lyell Salamander to more wide-ranging species such as the genus Batrachoceps. With such a wide variety of unique salamanders in California, it is hard to pick a favorite. However, one that has always stood out to me is the Arboreal Salamander (Aneides lugubris), as species found only along the Western Sierra Nevada and the coastal mountains of California and Northern Baja California. Everything about this weird salamander species interests me. For one, it is a member of the family Plethodontidae, the most diverse family of salamanders. All plethodontid salamanders are unique in that they lack lungs, meaning that all of them rely entirely on their skin for respiration. They also spend their entire lives on land and lack the larval stage of development that many other salamanders have. In addition to their neat physiology, Arboreal Salamanders have an intriguing life history. Like most salamanders in California, Arboreal Salamanders emerge from estivation during the first major rains of the winter and spring and stay active until the logs and other objects they use for shelter dry out. While they are usually found on the ground or on rock formations, they can, as their name suggests, climb trees. Some have been found several feet up trees and it is likely that they use tree cavities to estivate during the dry summer. Rock crevices and logs can also be used as estivation sites, where as many as a dozen individuals can be found together. The majority of their diet consists of a wide variety of invertebrates and fungi, although they can eat larger prey items such as small salamanders. Whatever the Arboreal Salamander eats is quickly torn apart by its sharp teeth. Although it rarely bites people when handled, it occasionally does and can leave quite the wound. Its sharp teeth and strong jaws alls assist the males in defending territories and mates during the winter, when it is not uncommon to see individuals with scars on their bodies from fights. Rather common in the Northern part of its range, the Arboreal Salamander is rather spottily distributed in the Southern half of its range and is a good find anywhere South of San Luis Obsipo, CA. It can be found in a wide variety of wooded habitats, from pine forest and redwood forest, to oak woodlands and riparian corridors with sycamores. On top of all of this, the Arboreal Salamander is just straight up weird looking. Its head is wide and bulky with bulging eyes. Its toes have unusually wide tips to help with climbing. Its tail has many caudal grooves, which along with the maroon color make the tail look like an earthworm. If there was a salamander that was actually an alien in disguise, this would be it.

I have been wanting to learn about this species’ habits in the wild since I first learned about the species in 2020. I managed to find my first Arboreal Salamander in the Santa Cruz Mountains in 2021 and my first subadult from Southern California in 2022, but I still wanted to see more of this species and better understand how to find it in wild reliably. For this, I got lucky with the 2022-2023 rainy season, which turned out to be one of the wettest years on record for California. One adventure that I already had planned for this rainy season was to visit the Bay Area to try and find salamanders there. There was one spot in the East Bay at the top of hill at the edge of a pine and oak forest, where I was able to find 9 Arboreal Salamanders under logs under pieces of bark, 2 subadults, 3 adults, and 4 hatchlings. It was really cool to get to see a great variation in the looks between the life stages of the species, as well as to see an old egg mass attached to the underside of a log with a hatchling underneath it. One of the adults also had unusually heavy spotting, making it an even more impressive salamander. From surveying that site, it was clear to me that most of the Arboreal Salamanders there were using either rotten logs, burrows, or tree cavities to estivate. This makes sense given that large trees and logs were in plentiful supply in this habitat, and I am guessing that this is the case for pine and oak forests throughout the Bay Area.

But I also wanted to learn more about the Arboreal Salamanders in Southern California since they are rarer in this part of their range. Thanks to my friend Brandon Troth, I knew a site where the species is occasionally seen under logs in an oak woodland, and this is where I saw my first individual from Southern California in 2022. However, I could not help but wonder where the Arboreal Salamanders go during the summer and why the species is only occasionally seen under logs at the site. Could it be that the species was just uncommon in this area? One thought I had was that the Arboreal Salamanders may be using a rock formation in the oak woodland as shelter. This would make sense given that the species does use rock crevices in other parts of its range. As luck would have it, I was looking for salamanders under logs at the site with Brandon during a heavy downpour in Early January and decided to shine a flashlight into some of the cracks of the rock formation to see what was there. I was not expecting to see anything, but I figured it was worth checking anyway. I am so glad that I did, because I was surprised to see an Arboreal Salamander deep in a crevice. I did not get a good look before it backed up further into the crevice, but I was so happy to see one in the crevice. A few more minutes of searching revealed three more Arboreal Salamanders in crevices. This proved my theory that the species was using the rock formation as shelter during the summer months. I also realized that these salamanders were preparing to leave the crevice at dark and walk around at night. I simply had to see this. I came back just a few minutes after sunset, with the rain still pouring hard. Sure enough, I saw several adult and subadult Arboreal Salamanders emerging from cracks in the rock to forage during the night. I was also lucky enough to see a huge, very old adult male emerge from a hole beneath a large rotten log. This salamander was at least 8-10 years old and the king of his domain. Earlier in the winter, Brandon and I had found a subadult with fresh wounds under a log next to where we found this large male, and it is very likely the large male pushed the subadult out from under the rotten log. Later in the wet season, Brandon and I went out again at night to do a more dedicated search for the Arboreal Salamanders during another rainy night and it was definitely worth it. We ended up seeing 24 Arboreal Salamanders of several different life stages and even got to see one climb a tree. It is clear to me that the presence of the rock crevices has a major role to play in the abundance of the species at this site, and it is likely that rock crevices and caves are important habitat features for the Arboreal Salamander in Southern California, although rotten logs, burrows, and tree cavities are also likely used as shelter. It is also clear that the best way to find this species is to look for the salamanders as they emerge from their shelters on rainy nights, just after dark.

I will never forget that first night of seeing Arboreal Salamanders emerging during the winter rains. It was simply amazing to get to see some great specimens of my favorite salamander and to finally learn how to find this species in Southern California. Figuring this out has to be one of the most rewarding herpetological discoveries I had made so far.

Publicado el abril 25, 2023 01:45 MAÑANA por tothemax