This was our second year going to the Caribbean with Renee and we can say without a doubt that it gets better every year. This year Shiloh and I looked at sea urchins and their effect on coral health. We looked to see if there was a corelation between the number of sea urchins and the overall health of the coral. Our findings did not turn out to be significant but we did learn a lot. One of the issues that could have affected our data (hindsite is always 20/20) is that sea urchins are more active and widely dispersed during the night. So it would help to either collect during the night or only count the sea urchins that are active during the day. Maybe someone next year can look into this study again. Unfortunatly for Shiloh and I this was our last year because in May we graduate. We would both like to say a special thanks to Renee and Morgan for making our last J-term a memorable one.
~ Cassidy and Shiloh
Since the introduction of the agave weevil to St. John in 2000, the invertebrate pest has decimated the native century plant (Agave missionum) population. Our objective was to determine the pattern between century plant health, size, and location on the island. Using a transect method, we located century plants in four locations (two on the north side of the island and two on the south side) and classified them by size and health. Given the high percentage of healthy XL agaves in northern shrublands, some resistance to agave weevil may be present in the St. John population. This conjecture is supported by the large percentage of healthy XS agaves. Further research is needed to gain a clear picture of the pattern of century plant health, habitat type, size and agave weevil presence on St. John
~Asya and Suzanne
Fish species such as the Bar jack are commonly found in association with stingrays, and may take advantage of feeding opportunities and protection from predators. The companion fish may influence the stingray’s response to an approaching predator. As such, we predicted that Southern stingrays (Dasyatis americana) with an companion fish would react to the approach of a diver sooner then if there was no companion fish. We collected response data on Stingrays with (N=6) and without (N=7) a companion fish by approaching from the front, back, and side. Surprisingly, we found that stingrays responded more frequently (P=0.003) without a companion fish. In addition, stingrays responded to approaching divers from a greater distance when swimming alone than with a companion fish (P=0.0641). Stingrays without a fish responded to approaching divers at a greater distance in shallow water while stingrays with a fish responded to divers at a greater distance in deeper waters. Our data showed interesting trends in behavior but further research and data collection of more Stingrays is needed to reach a more definite conclusion.
~Sarah and Becca
My project was on the abundance patterns of Bluehead Wrasses (BHW) on Coral Outcrops. I found BHW make up a larger proportion of the fish biomass on coral outcrops sampled. Over 50% of all fish on outcrops were BHWs with highest percentage on Fire coral (86%) and the lowest on Brain Coral (58%). Terminal BHW account for 20% or less of all BHW on coral outcrops. As initial and juvenile phase BHWs can act as cleaner fish, these heads may serve as cleaning outposts. More study of feeding behavior of BHWs on coral heads is needed. This project was so much fun!!! Next year I hope to return to St. John ando carry out a more indepth study on bluehead wrasses. I am so full of excitement already!!
I give a huge thank you to Renee and Wilson for making this trip so successful and possible forHollims students to go on.
Also a huge thank you to my parents, Clint and Kathy, for making such an amazing trip possible! I could not have this experience without you two!Love you guys so much!
Parrotfish (Scaridae) play an important role in keeping coral reefs healthy by consuming dead or dying coral and providing coral with places to regrow by scraping algae off rocks with their parrot-like beaks. My research objective was to determine if there was a relationship between the percent coral cover in a habitat and the density of parrotfish found there. As such, I hypothesized that parrotfish populations would be most dense in habitats that contained coral colonized bedrock. I surveyed eight locations on St. John, USVI and took four samples at each site, estimating the percent coral cover and counting the number of parrotfish within a ten foot radius at each site. A Spearman Rank correlation indicated a significant, positive relationship between coral density and parrotfish density (P=0.029). Thus, it is likely that parrotfish are attracted to areas of coral colonized bedrock rather than areas of strictly coral reef and their presence may therefore positively affect coral health. Further research in more locations could be done to provide further evidence for this correlation.
Well, now that my research is out of the way…our trip to St. John was undoubtedly one of THE best experiences of my life. I learned more in ten days than I ever have in months of classes and I made some down-right amazing friends.
To Renee and Morgan, thank you both so, so much for helping to make this possible for me. I don’t think I could ask for better or more understanding professors. You both made this such a wonderful experience and I thank you for opening this door for me.
I would also like to extend my most sincere gratitude towards the Hobbie Grant Fund and to Ms. Claudia Belk for providing me with the funds necessary to make this trip possible for me. There is no way that I would have been able to go on this trip without your generous contributions. This was a life-changing experience for me, and I thank you from the bottom of my heart.
A HUGE “thank you” needs to be said to VIERS (Virgin Islands Environmental Resource Station) and all of the staff and volunteers there for being so welcoming and helpful while we stayed at their facilities and for supporting us as we conducted our research. We all felt absolutely spoiled rotten while there, you guys are the best!
Finally, I would like to thank my family for supporting me through this entire process. I know that we had all pretty much just put the idea of this trip in the beacks of our minds, but the impossible happened and now I have an unforgettable experience to tell you all about. Thank you guys, I love you all so much.
Caribbean termites (Nasutitermes acajutlae) are important to the terrestrial ecosystems of St. John because they decompose dead wood and make nutrients available to plants. They can also build nests up to 7 ft tall and 4 feet wide! For my research project, I wanted to see if there was any difference in density and nest placement in moist and dry habitats. I counted a total of 119 termite nests (48 in dry and 71 in moist) and recorded their relative height in relation to their nesting tree (eg: 0% ground level, 100% top of the tree). I found that nests in moist forests were significantly higher up their host trees than those in dry forests. Most likely this is due to the fact that trees are bigger in moist forests, and thus can structurally support nests higher up. I also found that Caribbean termites seem to prefer dry forests over moist forests. This could be due to a difference in resources. Perhaps there is more dead material for termites to consume in dry forests.
Dry or moist, St. John is a beautiful island, and I hope to return again someday. I especially enjoyed meeting people at VIERS which is near impossible at a hotel where everyone wants their privacy. Everyone at VIERS was friendly, kind, and a joy to be around. The VIERS volunteers and staff took such good care of us. I even got one of them to juggle with me! Thank you VIERS! On that note, big thank yous to Renee Godard and Morgan Wilson who proved they are not only good teachers, but also good surgeons (they pulled a cactus out of my foot). A Thank you to Claudia Belk and the Hobbie trust fund for making it a lot easier for me to go on this trip, a thank you to my family, and finally thanks to all the other women who accompanied me, particularly Caitlin who helped me with my termites. You are all so amazing!
Studies on the effects of introduced species on an ecosystem show negative results. On the island of St. John these species include: donkeys, cattle, cats, dogs, goats, sheep, white-tailed deer, and mongoose. In my survey of the environment each non-native mammalian species was recorded with respect to habitat (dry forest, moist forest or VIERS field station). Population densities within the forest habitats were estimated using total mileage calculated through out our trip. Populations within VIERS were estimated per day. Mongoose were particularly popular at camp while donkeys, goats, and sheep were more abundant in dry forest havitats. Overall, introduced species populations were far mroe likely to be seen in dry forest. This might be explained by several initiatives founded by the Virgin Islands National Park (VINP) to reduce populatins of invasive species within park boundaries.