This blog post tells the #StoryBehindThePaper from the perspective of one author, Matt Jenkins, for the article “Natural and anthropogenic sources of habitat variation influence exploration behaviour, stress response and brain morphology in a coastal fish” by Matt Jenkins, Jack Cummings, Alex Cabe, Kaj Hulthén, Nils Peterson, and Brian Langerhans, which was recently published in the Journal of Animal Ecology.
As the human population continuously grows and cities become more common throughout the landscape, it is becoming increasingly important to study the effects of urban phenomena on the organisms inhabiting these modified environments. Human-induced habitat change has repeatedly caused behavioral and evolutionary trait shifts in organisms that persist in the Anthropocene, but we are still in the early days of understanding the causes and consequences of these shifts.
My part in this study began during the spring of my junior year at NC State University. With the fortunate experiences of already participating in several urban ecological studies as an undergrad, I discovered my passion for studying urbanized ecosystems. I was searching for ways to gain more experience in this field when I happened to notice a flyer one day as I was walking to class. Something on a bulletin board caught my attention: a research-centered study abroad trip to Andros Island in The Bahamas, led by Drs. Brian Langerhans and Nils Peterson. Based on the information provided on the flyer, it seemed the program involved group projects where students designed and carried out their own research project on the island with the goal of publishing their findings. Taking courses and conducting research all while staying on an island paradise? I couldn’t apply fast enough and had my application submitted that evening. A few weeks later I received an email from the study abroad office letting me know that I had been selected to attend.
The end of May quickly arrived, and it was time to depart for Andros. This would be my first time both flying alone and internationally. All went smoothly, and everyone on the course met in Nassau, The Bahamas to board the small propeller plane to Andros.
We soon had our first course lecture of the trip preparing us for what to expect during our time on Andros. After an amazing first week exploring the island, learning research techniques, eating local cuisine, and snorkeling along the barrier reef, my group got to work finalizing our project design, writing a research proposal, and presenting our plans to our classmates and professors. With my “teammates” Alex Cabe and John Cummings (co-authors), we decided to examine how ecosystem fragmentation and habitat complexity might affect the exploration behavior, stress response, and brain morphology of Gambusia hubbsi, the Bahamas mosquitofish, that reside in tidal creeks. During the 1960s and 70s, roads were constructed throughout the island, resulting in the fragmentation of some of these creeks, cutting off native species from the ocean and resulting in strong ecological change. Bahamas mosquitofish is a resilient species that has persisted in these altered environments and are abundant in many bodies of water on the island, making them a good model for testing adaptive shifts resulting from habitat change.
Our first day of field work was one of the biggest wake-up calls I have ever experienced. When one thinks of The Bahamas, your first thought is probably of white sandy beaches, fancy resorts, and crystal clear water, and while parts of the island certainly do look like that, it was not the case where we were on Day 1. Our first field site greeted us with temperatures in the high 90s, jagged rocks everywhere, the relentless biting of “doctor flies,” and a ubiquitous plant called poison wood (which you can tell by the name, was not a fun time). But with positive attitudes and hard work our team quickly got into a routine and our field work got smoother and smoother. It was actually the harsh field conditions that really brought us closer together and gave us some hilarious stories, like finding an abandoned bar to set up our behavioral assays beside an unfragmented tidal creek, and having plenty of interesting interactions with local people.
Our hard work paid off: after collecting and examining 356 mosquitofish from 7 tidal creeks (4 unfragmented and 3 fragmented), we found that not only has natural variation in habitat complexity resulted in several phenotypic shifts that point to intriguing future directions, but perhaps more surprising was that human-caused habitat modification has inadvertently led to changes in how a native animal interacts with and responds to its environment: Bahamas mosquitofish in fragmented tidal creeks showed greater exploratory behavior, a stronger stress response, and a smaller telencephalon (part of the brain most responsible for fear-related learning and spatial memory). All of these changes may represent adaptive shifts in response to the reduced predation pressure and tidal dynamics caused by fragmentation.
So, an undergraduate study-abroad experience led to this study in Journal of Animal Ecology, but it also solidified my passion for conducting urban ecological research and my desire to pursue this work in graduate school and eventually become a professor in this field. In the spring of 2019, I was fortunate enough to begin my Masters research with Dr. Langerhans where I am currently examining another major effect of human activities on native animals: artificial light at night. The findings of this study taught me that human actions can alter diverse types of animal traits in a relatively short time frame, and we need to better understand both how predictable these shifts might be and what sorts of ecological and evolutionary consequences result from the trait changes.
Read the paper
Read the full paper here: Jenkins, M.R., Cummings, J.M., Cabe, A.R., Hulthén, K., Peterson, M.N. and Langerhans, R.B. (2021), Natural and anthropogenic sources of habitat variation influence exploration behaviour, stress response, and brain morphology in a coastal fish. J Anim Ecol. Accepted Author Manuscript. https://doi.org/10.1111/1365-2656.13557