Salamander Decline; The Results are in!

Mole Salamander

The effects climate changes have had on amphibians are insurmountable. Salamanders are amphibians and therefore rely heavily on a reliable water source in order to mate and for juveniles to grow and develop. A recent US Geological Survey (USGS) study was highlighted in two separate articles. Each article comments on the USGS effort. It was interesting to read two separate viewpoints on the topic. The USGS’s Amphibian Research and Monitoring Initiative (ARMI) focused their study on the effects climate change has on mole salamanders, which have a similar lifecycle to flatwood salamanders, but are easier to gain access to. Both of the articles described the ARMI study in a fair amount of detail. Essentially from the ARMI’s effort they found that droughts and deluges are decreasing the populations of both types of salamanders in the southeastern part of the U.S. Climate change is going to cause these weather patterns to change dramatically. Salamanders rely on rainfall to be consistent so as to allow them to mate accordingly with the seasons. If their ponds are overly full and spill into nearby ponds where other fish can gain access and eat the newly laid salamander eggs, then that generation will see dramatic decline. On the other hand, if salamanders were to lay their eggs in a pond that was experiencing a drought, that pond would dry up and eliminate the only resource juvenile salamanders could rely on to develop. To address this issue the ARMI initiative examined whether or not habitat conservation would have any positive effects on amphibians. They looked specifically at the USDA Conservation Service Wetlands Reserve Program (WRP). This program is voluntary and encourages landowners to restore and protect wetlands on their property. Thirty randomly chosen WRP sites were observed and found to have a greater diversity of amphibian species than did the twenty randomly selected agricultural sites. The articles pointed towards a bright outcome, but more research into the implementation and long term effects of the WRP are necessary before anyone can say with 100% confidence that this voluntary initiative is actually effective.

Climate change poses a huge threat to species that have dispersal and physiological limitations. The article, "Projected Loss of a Salamander Diversity Hotspot As a Consequence of Projected Global Climate Change” by Milanovich et al. highlights just how impactful these climate changes have been. Salamanders are unable to adapt to the dramatic weather patterns caused by global warming because they can only inhabit a

The projected species richness in the Appalachians for each of the scenarios
Projecting species richness will be close to zero(black) if CO2 levels
continue to increase at its current rate 

certain region. For instance, the southern Appalachian Mountains are a global hotspot for plethodontid salamander diversity. Because they are lung less ectotherms (use external heat source to regulate body temperature) their ecology is strongly governed by temperature and precipitation. By imitating what they think the climate will be like in 2020, 2050, and 2080, the researchers in the next article made the assumption that the salamanders in the Appalachian Mountain region would decline. They used the species distribution modeling tool to generate eight scenarios per species of salamander. They looked at forty-one species in total and every projected scenario demonstrated a decline, including as early as 2020. These scenarios are simply that: scenarios. However, current technologies being utilized are able to incorporate many, if not all of the necessary parameters to make a fairly good estimation of what climatic changes would occur in the coming years and how salamanders would be affected. Salamanders are located at the center of the food chain. They control insect populations while also being a food source for other creatures. The decline of salamanders would be disastrous for a lot of ecosystems that heavily rely on them.

        The Chinese Montane Salamander was the focus of the article entitled, “Significance of Pre-Quaternary Climate Change for Montane Species Diversity: Insights from Asian Salamanders”, written by Wu, Wang, Jiang, and Hanken. In this article climate change is yet again highlighted as a leading cause for salamander decline. The monsoon season in East Asia has intensified due to global warming. This has caused a dramatic

Chinese Montane Salamander

change in the climate of the salamanders. The monsoons, because of their severity and length are causing multiple stream systems to connect to each other. This is making it much more difficult for these salamanders that must now compete with other amphibians and smaller aquatic dwelling creatures. The monsoon season is also marked by an increase in temperature and humidity. The current climate change has led these researchers to believe that a Pliocene warming effect is occurring in this region. There is evidence that this period in time marked the decline of other salamander species in this area. This article insists that if these salamanders are pushed out of the range of their temperature buffer zone that they will not survive. Salamanders live half of their lives in water and the other half on land. Their skin is extremely permeable and the effects climate change have already begun to have on multiple salamander species across the globe is gigantic.

     Salamanders and other amphibians are obviously being hit from all directions when it comes to their decline. The literary article, “Declines in Woodland Salamander Abundance Associated with Non-Native Earthworm and Plant Invasions”, by John Maerz describes how the invasion of non-native plants and earthworms are causing a decrease in forest floor leaf litter. A decrease in forest floor fauna in observed, in this case salamander fauna. From this article they could not indefinitely prove that earthworm and plant invasions were the sole cause of salamanders decline, but that they play a major role. They were able to

Figure above showing that P. cinereus (Red Back Salamander)
without the presence of earthworms have a greater abundance

determine that sites with high earthworm biomass were invaded by non-native plants. Therefore, plant invasions appear to be symptomatic rather than a cause of degraded forest habitats for salamanders. The reason why non-native earthworm invasions are occurring is relatively unknown. However, a major finger could probably be pointed at climate change. The article suggests habitat fragmentation and habitat alteration as triggers for this invasion event. What is clear from this article is that salamander populations in this area are declining. Regardless of what the mechanisms may be, we are facing a mass extinction event. Salamanders and other amphibians are extremely susceptible to minute changes in their environment. We as humans must be more vigilant in understanding and reducing the effects climate change, invasive species, and habitat fragmentation may all have on various species of salamanders across the globe.

Ball, Lianne, Gabrielle Bodin, and Rachel Pawlitz. “Increasingly Erratic Rainfall Patterns can lead to Declines in Southeastern Frog and Salamander Populations, but Protecting Ponds can Improve Their Plight.” Red Orbit 19 May 2013: 1. Red Orbit Online. Web. 20 May 2013.

Maerz, John C, Victoria A. Nuzzo, and Bernd Blossey. "Declines in Woodland Salamander Abundance Associated with Non-Native Earthworm and Plant Invasions." Conservation Biology. 23.4 (2009): 975-981. Print.

Milanovich, JR, WE Peterman, NP Nibbelink, and JC Maerz. "Projected Loss of a Salamander Diversity Hotspot As a Consequence of Projected Global Climate Change." Plos One. 5.8 (2010). Print.

USGS. “Front Row Seats to Climate Change.” 21 May 2013: 1. Environmental Research. Web. 22 May 2013.

Wu, Y, Y Wang, K Jiang, and J Hanken. "Significance of Pre-Quaternary Climate Change for Montane Species Diversity: Insights from Asian Salamanders (salamandridae: Pachytriton)." Molecular Phylogenetics and Evolution. 66.1 (2013): 380-90. Print.