Reflection
During class this week we read de Souza et al’s paper, “Environmental DNA (eDNA) Detection Probability Is Influenced by Seasonal Activity of Organisms,”. During our group discussion of the paper, some interesting points rose to the surface that have stuck with me, especially as some members of our class embark on our own eDNA study projects. With regard to the study design in the paper, we noticed the large increase in number of samples collected from year one to two (“16 cool season and 18 warm season sample sites in 2013, and 60 cool season and 48 warm season sample sites in 2014”, p. 4), and wondered if perhaps the first year was a pilot study which then led to the second year implementation of a larger sample collection. We talked about the length of sampling time (two years), which we wished was longer to collect more data, but also recognized constraints such as funding, time, and other elements may have factored into the choice of the time period.
This paper draws particular attention to is the conservation status of both species: N. alabamensis is listed on the National Fish & Wildlife’s endangered species list, and S. depressus is listed as threatened. Both populations “are believed to have suffered population declined due to habitat fragmentation and degradation in water quality associated with land use change (e.g. logging, mining, urbanization, etc.)” (p.3). This discussion point led to us to learn about a massive wastewater spill and fishkill on the Black Warrior River in 2019. Our group wondered if another eDNA study is being conducted to look into the status of the population and what changes may have occurred since 2013/2014.
Another point we discussed were the lack of species images who have very interesting common names: the Black Warrior Waterdog (Necturus alabamensis) and the Flattened Musk Turtle (Sternotherus depressus). We also mentioned that an image of the habitat would have been helpful to illustrate the connection of the species to particular sections of habitat, e.g., “N. alabamesis had a “positive relationship with steeper terrain slopes” (p. 8). Part of my background is in publishing and the common approach for a piece was to include an environmental image of the subject, so I am often surprised by the image scarcity of primary species in scientific articles. This detail seems to be a leftover from the printing era where publishing constraints and high costs of printing (especially color) restricted articles to fewer numbers of images. All that said, I know how difficult it is to balance conducting research and remembering to capture images in the field or lab, especially microscopic organisms!