A red-spotted newt (Notophthalmus viridescens) I found at Table Rock, SC Many of us know that the region we live in, the southeastern US, is home to some of the greatest diversity of amphibian species – particularly salamanders. But just how rich is this diversity, and how common are our slimy little friends? I decided I wasn’t going to take this fact for granted, and read up on the topic myself so I can summarize it here. Heat map illustrating amphibian diversity in the continental US. Taken from the Gulf Coastal Plains & Ozarks Landscape Conservation Cooperative website Map showing the extent of what is considered the Appalachian region extending from its southeastern extents in Alabama and Mississippi to its northern limits in New York. As it turns out, this region is very much a hotspot for salamanders and for amphibian diversity in general!
According to the proceedings of the Salamander Conservation Workshop hosted by the Smithsonian’s National Zoological Park a few years ago, the Appalachian region of the US is home to 14% of the world’s 535 salamander species. This makes it a hotspot for salamander biodiversity, and nearly half (35) of the 76 species that reside here are endemic to this region (Stuart et al, 2004). These 76 species come from a wide range of genera with the largest (29 species) being Plethodon - also known as woodland salamanders. There are also many Desmognathus, a few Ambystoma, Gyrinophilus, and even a Cryptobranchus - the Hellbender! Many of these have unique and specialized habitat requirements, but they all are able to find a home within this biodiversity hotspot of the Appalachian Mountains - also known as our own backyard! There still remains some uncertainty on the overall status of salamanders in this region, however. It is very difficult to estimate population size when salamander detection is very difficult. Most of the species in this region are nocturnal, terrestrial, and very adept at staying out of sight of researchers attempting to catalogue their abundance. Over the summer, I went on a few trips to go catch salamanders in the mountains of North Carolina, and I remember with great detail the struggle of finding salamanders among all of the camouflaging leaf litter. Not everything pertaining to salamander abundance in the Southern Appalachians is good news, unfortunately. According to a series of long-term studies by Richard Highton (2005), the populations of 38 Plethodon salamander species may have declined as much as 50% from the years 1990-2000. The exact cause of these changes remains uncertain, but it is clear from these studies and many others that the salamanders here are in danger and we may not remain as such a hotspot for salamander biodiversity for long. Global climate change is likely to lead to a decrease in favorable habitat for many salamander species in the near future, if it hasn’t been contributing already. Because of this, it is important to better understand the diversity we currently have and to learn how we can help preserve it for future generations. References: Highton, R. 2005. Declines of Eastern North American Woodland Salamanders (Plethodon). Pages 34-46 in M. Lanoo, editor. Amphibian Declines: Conservation Status of United States Species. University of California Press, Berkley. Stuart, S., J. Chanson, N. Cox, B. Young, A. Rodrigues, D. Fischman, and R. Waller. 2004. Status and Trends of Amphibian Declines and Extinctions Worldwide. Pages 1783-1786. Science. American Association for the Advancement of Science.
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"Your child has autism." These words can be scary and overwhelming for a parent to hear. About five years ago, my aunt heard these words when my younger cousin was diagnosed with a form of autism. Since I am quite close with my aunt, I was involved with a lot of the intervention services he received and as a result I learned a lot about the disorder. Autism spectrum disorder or ASD refers to a number of complex brain development disorders. Symptoms of these disorders include difficulty with social interaction, communication both verbal and nonverbal, and even repetitive behaviors. Before my cousin was diagnosed with autism, I knew little about it, just like many other people personally unaffected by it. However, with rates of autism on the rise and no clear cut cause or cure, I think it is important for autism awareness to increase. As of March 2014, based on information from the CDC, one in sixty-eight children have autism, and it is more prevalent in boys than in girls. Since there is no clear cut way to diagnose ASD, the real prevalence of autism may be higher. With autism becoming so common in recent years, I think it is important for people to educate themselves and learn more about it. What causes autism? Autism has a wide range of symptoms which suggests it could have a wide range of causes. For example, when you get a sore throat, your sickness could have been caused by a variety of different things. You may find out that your infection is viral or maybe it’s bacterial and you need antibiotics to treat it. The same goes for autism, there may be many different ways to arrive at the same end result. (From a genetics perspective, there is no specific gene that causes autism but there are genes associated with it. Autism is not solely heritable, as there are many different environmental ‘risk factors’ that come together to cause autism. High maternal age at the time of conception, maternal prenatal medication, gestational diabetes, and bleeding during pregnancy may all contribute to the development of autism. Autism is also correlated with abnormal neurological development of the baby during pregnancy which itself has many causes. Other external factors may contribute to the cause of autism and researchers are currently studying a possible correlation between high stress levels of the mother during pregnancy and the child developing autism. I find this interesting in how it relates to what we are studying in lab where we are looking at the stress levels of salamanders and how stress affects their blood on a cellular level. Even though salamanders and human children are different test subjects, stress affects both adversely. A study done by Ohio State University Medical Center found that mothers who had a highly stressful event during their pregnancy such as a loss of a spouse or loss of a job had a correlation with having a child with autism. People who have autism are known to have an abnormally formed cerebellum and it is possible that combined with other risk factors, a high stress event during pregnancy may cause this abnormal development of the brain (Beversdorf 2013). You can read more about that study here. http://mentalhealth.about.com/library/sci/1101/blpregnant1101.htm A little stress from time to time is normal and unavoidable, and so long as the stress is short term, your body will relax and your chemistry will return back to normal. The danger comes in with chronic stress which causes your body to trigger an inflammatory response. If you are pregnant, this could negatively affect the fetus’s brain development. So can extended periods of high stress levels cause autism? Maybe, we’re not exactly sure yet and more research needs to be done. What does NOT cause autism? Say it with me, vaccines. I get frustrated and sometimes angry when I hear people claim that vaccines are bad and that they cause autism and expose your child to a complex of harmful chemicals. A study was done by Dr. Andrew Wakefield claiming that the MMR vaccine causes autism. If this was true, this would be an alarming finding. The problem however, with Dr. Wakefield’s work was that he was paid in order to find a link between autism and vaccines which created a conflict of interest. A good scientist should be unbiased and he was not. He was trying to show that autism is caused by the MMR vaccine so that lawyers could sue the vaccine manufacturers and make a profit. Dr. Wakefield also misrepresented or altered the medical history of the twelve patients in the study. Five of his subjects showed symptoms before receiving the vaccine, and three of the patients didn’t have autism at all. His paper created a panicked uproar and decreased overall vaccination rates. Not only was he wrong, but due to the ignorant sense of fear he has helped spread across the world, people are choosing not to vaccinate their children allow previous practically eradicated diseases to spread across the population again. Now before I go off on a rant about vaccination and herd immunity, just know that the study done by Dr. Wakefield was not sound science and those who have studied the same subject since have failed to find a link between the MMR vaccine and autism.
If you're interested, here is a link to 107 studies that show there is no link between MMR and autism. http://www.cnn.com/2011/HEALTH/01/05/autism.vaccines/ ~Alexa As Clemson’s Biological Sciences Annual Student Symposium is soon approaching, I’ve decided to blog a bit about my experiences at other symposiums and conferences. I’ll recount some of the things that I’ve learned from these experiences as a way to prepare for this upcoming conference! So here we go with a recounting of my most recent conference experience! Last August, I had the great opportunity to go to Baltimore and attend the centennial meeting of the Ecological Society of America. While I was there, I was overwhelmed, intrigued, and inspired all at the same time. The conference lasted five days, and each was jam-packed with lectures, talks, workshops, and posters. My first day at the conference was spent running back and forth between talks on a wide range of ecological topics. Because the conference was so filled with talks with little breaks in between, this proved to be a mistake. While very informative and interesting, the sheer number of talks I attended proved overwhelming and left me exhausted. The second day I decided to pace myself and carefully chose beforehand which talks I would attend. I made sure to give myself some breaks and plenty of time to digest what I had just learned. One of my favorite parts of the conference was that they had a poster session nearly every evening of the five day event. I greatly enjoyed walking around the poster show floor and perusing the wide variety of scientific posters and infographics on display. I think that the poster format for sharing scientific information is so great because it allows important discoveries and innovations to be easily received and digested by a wide range of audiences. This format also allows for you to personally meet and interact with the authors or researchers behind your favorite presentations. At ESA, I really liked being able to browse the different posters, find ones that interested me, and then discuss the poster with the very person who worked on it. Because the poster is usually presented by the hands that carried out the research, you can often get a personalized and in-depth description of the study, which makes it much more relate-able than reading a journal article or hearing a lecturer present their findings. The experience I gained from my trip to ESA's 100th annual meeting was far beyond what I expected, and I would definitely encourage anybody who hasn't to attend at least one regional or international biology conference or symposium. Maybe CBASS 2016 can whet all of our appetites for the next ESA! Conferences such as ESA are also great because they're often held in really cool cities (like Baltimore!). If the conference itself isn't motivation enough to attend a regional or international conference, maybe the chance to explore new cities will be!
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The Slime Times is written by the Stress After Dark Creative Inquiry TeamScience isn't all white lab coats and ivory pillars, sometimes you just need to get slimy. Archives
August 2016
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