Yasuní Biosphere Reserve, Ecuador
Weekly Research Log
Here, I will be discussing the details of my research week-by-week. I'll touch on what is expected, and what is unexpected. What is easy, and what is more difficult. I'll go through the highlights of my project, and most importantly I'll be discussing all the new things I learn!
Project Synopsis
What exactly am I studying?
Over this summer, I will be studying the effects of "defaunation" on snake population abundance and diversity in the Ecuadorian Amazon. Defaunation is a term used to describe the process by which large and medium-sized mammals are reduced in an ecosystem. Many different anthropogenic activities lead to losses of these functional groups across the globe. Within the Yasuní Biosphere Reserve in eastern Ecuador, unsustainable hunting is the primary mechanism by which defaunation occurs.
I hypothesize that these losses of large mammals should decrease the overall snake species diversity, and increase population size. Losses of large mammals have been known to increase small mammal abundance due to less direct predation, less competition, and changes in vegetative cover. If there are increases in small mammal population sizes, there should be an increase in snake genera that prey upon them (eg. Boa, Bothrops, Corallus, etc.) In addition to this increase in food resources, I will be attempting to explore whether or not the defaunation-induced changes in vegetative communities have an impact on the diversity and abundance of snakes. I have included a flowchart below of the potential species interactions I am expecting.
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I will be conducting this study within the Yasuní Biosphere Reserve. Throughout the summer, I will be rotating between the Tiputini Biodiversity Station (TBS) and the Yasuní Research Station (YRS) every two weeks. TBS has very little anthropogenic influence and is only accessible by boat, and it will be the site I use as the basis for snake population patterns without defaunation. YRS has had hunting practices for a number of years now, and it will the the site I use to explore snake population patterns with defaunation. To estimate small mammal abundances, I plan on using data from camera traps. In addition to this, I will also be quantifying differences in vegetation composition such as percent canopy cover , understory density, and more. Lastly, to study the snakes I plan on using transect surveys coupled with distance sampling for abundance, and potentially using an index to estimate diversity.
Week 1 (6/10-6/16)
The first week was filled with ups and downs in terms of my actual project, and I am quickly learning that adaptability is a key attribute throughout this process. I have already had to make a great amount of adjustments, (and read a great deal more papers) just to figure out how to get some viable data. However, I am feeling pretty pleased with how the progress has gone with these changes. At first on my night surveys, I wasn't getting as high of a sample size as I had wanted with snakes alone. This caused me to re-evaluate how I am counting snakes. I have decided to use a new method of data collection by using the third-party researchers who are also here as well as by recording opportunistic encounters on non-survey walks. This has caused me to almost double my diversity, and add 4 more individual snakes to my project. I also have formulated a backup plan if this still isn't enough. I would also be interested in looking at frog population differences between my two sites. I read a really cool paper about how peccary (Amazonian pig) wallow pools can facilitate high tadpole diversity. If the peccaries are hunted out at the other site and there are no wallows, the frog diversity could be lower over there. The inclusion of frogs would also give me so much more data, as they are out in high abundance just about every single evening. I don't think there's been a day so far where I haven't seen at least five.
In terms of the other two projects, there has been a lot of camera deployment. This is something I wasn't anticipating. It has been very different from the work I normally do in my plant lab at UF, and there is a lot more of the animal interaction aspects that are included. I always enjoy looking back at the camera trap data though. It can be tedious, but it is also exciting to see the cool mammals you can capture on camera. At the end of the summer, I will collect my small mammal and rodent data from these same cameras that are being used for the other two projects, so we have been extremely meticulous when setting them up so as to include both the understory AND the ground, as the super small mammals will not show up if the camera is even just a little bit askew on its strapping. Overall, a lot of hands-on work has gone into both navigating the trail systems and getting research work done, but it's also been enjoyable.
Week 2 (6/17-6/23)
To be honest, I feel pretty good about how things have been going so far! The sample size has been far higher that I was anticipating, which I am super excited about. I was told my many herpetologists before coming to prepare for really low numbers, and that made me worried that sampling snakes wouldn't be sufficient enough information to make a claim about the food web. This is mainly why I wanted to include frogs, lizards, and pretty much all other herpetofauna as sort of a "Plan B". However, I have only had one survey where I did not get a snake at all, and that was mainly due to short trail length and poor weather conditions. It's been encouraging that I also have really only found one mammal-eating species so far, indicating my hypothesis could maybe possibly potentially be true. I do feel like the easier thing to do though is find the non-mammal eaters, so I really need the second part of the project of finding bigger snakes like boas to happen. The other station should have significantly more small mammals, and I am expecting more snakes of the genera Drymarchon, Boa, and Corallus, and I depart for that one early tomorrow morning by boat.
Even with more snakes than expected, the frogs have also helped give me more numbers to write down. I've found 30 since implementing them into survey walks, and 14 species. I have also been finding a few more wallows, so if I find that there aren't really any serpentine differences between the two stations I can sample the wallows. I have also been finding lizards, and even a salamander. In the analysis (if I end up using all herpetofauna) I won't really have a good solid reason if there are differences between sites for lizards, but I would sort of be excited to write about why this is an area that may need future research.
I am still sort of working on standardizing the starting and ending time of my surveys. Typically, they begin at 8:00pm and end around 11:30, but I've been noticing that I haven't really being seeing any snakes before about 9:15. I may start to make an adjustment at the next station to see if that maybe helps with numbers. I sort of feel bad because my night surveys just make the long days longer for my mentor, so I appreciate it when there are other herpetologists at the station who are willing to come with me instead so she can rest. For example, this past week we had a big group from the Galapagos Conservancy staying here, and there were three herpetologists here: two frog and salamander specialists and one turtle guy. They helped me a lot on my surveys and even spotted a snail-eater last night, which is coincidentally the same species of snake pictured by the Week 1 reflection.
Week 3 (6/24-6/30)
I've found myself being pretty tired towards the end of some of the surveys where I don't find as much. It really is a lot of walking for marginally very few snakes. I have honestly gotten almost double the amount of data from my opportunistic encounters and third-party sources, which can feel discouraging at times. It is still viable information, but it sort of annoys me that I have to put in so many effort hours just to sometimes not see anything. I was also looking forward to sampling the lake and flooded regions a lot, but ever since I've decided to include frogs in the surveys they have taken so much longer. These habitat sections are just so densely filled with frogs that I am having to stop about every 2 minutes and record tons of information, taking up time that I could be looking for snakes with. To me, the snake data is more valuable because I actually have a good background knowledge about why the communities could be different between both sites. For frogs, I really don't have any idea behind why there may be a difference, but it is also too late to remove them from surveys. I always do surveys with a partner, and my least favorite phrase of the summer has become, "Oop, I've got a frog over here".
The snake data I have gotten has been quite encouraging, however. Not encouraging for the ecosystem, as the data shows it is quite unbalanced thus far, but encouraging for my hypothesis. As soon as I got to this station a week ago, I found an Anaconda (huge mammal specialist) and two Rainbow Boas. I have also seen so many more small mammals on my night surveys in general, things like mice, rats, mouse opossums, and even a paca. One thing that seems to really affect the amount of snakes that are out is the weather. As you can imagine, the rainforest during the peak of the rainy season is, well, rainy. Which is annoying because the snakes really seem to not enjoy this soaking wet weather. The past 3 days have been especially bad, so hopefully there will be an influx once we see the sun again. We also will not be quite in the peak starting next week, and I am looking forward to perhaps a drier second half of the summer.
I feel like I have been having to add a new column to my datasheet after every survey, as there is just always so much going on out here and therefore so much new stuff to record. I am starting my journey in R though, and I look forward to doing my initial analyses just to see how all the variables are correlated with one another. The project has been getting more difficult, but I still have plenty of motivation to help me get through the tougher stretches.
Week 4 (7/01-7/07)
My datasheets are really starting to come together now, and I finally have a good enough sample size to where I can view some of the trends between both stations. Between my night surveys, opportunistic encounters, and third-party encounters, I have now accumulated over 40 snakes on the trip, and the goal was to get to 80 before leaving. Seems like I'm keeping a good pace for now. I am also really excited to report that I have gotten significantly more mammal eaters at this station than at TBS, which is exactly what I was hoping to find. One interesting thing I have also noticed, however, is that the diversity has actually been higher here as well, something I didn't expect. I figured that there would be so many more mammal-eaters and just a normal amount of generalist species, but that has not been the case. I think I have logged 5 more species here than I did at Tiputini. I'm happy I have been measuring frogs and lizards, as that could help me figure out if there is possibly a trickle-down effect to the other prey items that might be causing this. I think I actually am at 130 frogs now, so they seem to be pretty abundant out here.
In addition to trends in the snake populations, I have also noticed so many more rodents on my night surveys than at the other station. This past week, there was one night where I saw 9 within three hours, and Alyssa's camera traps have also picked up much higher numbers of small mammals here. It's pretty crazy to see the concepts we learned months before coming actually be happening at such significant levels. And while this is great data for my project, it's pretty discouraging for the actual ecosystem. This just means that most of the large mammals really have been hunted out of this part of Yasuni National Park.
I have come to really enjoy doing stuff for the umbrella seed enemies and dispersal project with my mentor, as I learn so much about plants and it is just a great opportunity to get into the forest during the day. Working on setting up the exclosure cages has allowed me to also get some great snake data just by chance when we see them on the trails or at the cage clusters. I got a Yellowtail Cribo this week, which is one of the largest non-venomous non-constrictor snakes in the world. Also a big mammal eater, which is always a plus at this station! I'm excited to return to TBS to see if I can try and get a bit higher diversity, especially since all the rain has hopefully pushed everything into the higher terrafirme habitat. Whatever happens, I am looking forward to more snakes.
Week 5 (7/08-7/14)
One of the more frustrating weeks I had to deal with regarding my personal project. The forest seemed completely dead for the majority of the time. The guides here had also been noticing that not many animals were active, from bugs to birds to snakes. I don't know if it could all be attributed to the Noah's Ark amount of rain we had been getting, but it was getting frustrating to spend so many hours out in the field just to not find anything of substance. It's not like I had been changing my methods or doing anything out of the ordinary from my normal surveys, but they just weren't working like they had before. I wasn't even getting opportunistic encounters or third party encounters, which was something I had typically been getting one of each day. I transferred back to TBS on the 8th, and hoped to add to my diversity and overall abundance count. I was looking forward to this so much that I even convinced one of the tourists here to accompany me on a night survey that very same evening. Not only were there no snakes, but there were hardly any frogs either.
Data input went from an interesting task to a dull job very quickly, as there was nothing cool to put into the sheets. Nothing to add to any sort of expected trends. Nothing to help prove my hypothesis. Some of the animals that appreciate wet weather were occasioanlly seen. For example, one day working on the plant enemies project we saw a super rare amphibian called a caecilian, though these animal sightings were few and far between. The days continued like this, with more and more rain, which I found out is not necessarily some extreme weather event, but is definitely somewhat unusual for this time of year. At one point, it had been three days since we saw the sun.
Then all of a sudden, on the final afternoon of the week, the rain stopped, and the sun came out again. Wouldn't you know it, the snakes did too. On that night I did a survey down a new trail, and was pleasantly surprised by a black and white calico snake crossing the path before we even got to the trailhead. I then proceeded to get 3 more snakes of different species while on the actual survey. Not only that, but when I returned to camp there were three more hanging out by the cabins: two watersnakes and a flame snake. I really felt like I needed this day to come after a very long, frustrating, and uncooperative week.
Week 6 (7/15-7/21)
It's amazing how quickly things can change around here. I go from getting zero snakes total across three surveys to sixteen total across the next three. I'm starting to think that there is a reason all the professors I discussed my project with back on campus warned me that snakes are so hard to sample for consistently. I think I also had expectations pretty high after the first couple weeks here of getting an average of 2 snakes/night. I also added some more survey routes so that I can get a better sense of how snakes are distributed throughout each area of the sites. This was a cause for more late nights but it also allows me to get more data when I go back to the other station again. I honestly was a little disappointed by some of the species I did end up finding during that crazy 3-survey stretch though. I was really hoping to not get very many species of the family Boidae on the surveys here at TBS, and I found two of different species of them one evening. Don't get me wrong, I love finding boas of any species, but it doesn't exactly help my hypothesis. Other than those two, however, there were a lot of other colubrids that did help support my study's questions. I am actually now worried about trying to "catch up" with my survey numbers when we rotate back, because as of right now I am sitting at 30 snakes at TBS and only 6 from surveys at YRS.
I am really looking forward to the fall when I can sort of compile all of this information and see what the differences in values are for snakes found on surveys vs snakes found opportunistically, because my ratio of the latter is far higher at YRS.
The research work for the main umbrella project has slowed down significantly. My tasks have simply included taking data, reapplying pesticides, and doing some seed collection. Towards the end of the week we did collect cameras again, though only one of the locations was difficult to access. The bulk of the work is setting up exclosures, and that was all completed towards the beginning of the week. And because my surveys are in the evenings well after dark, it has left me with many free afternoons and mornings. I am looking forward to our final transfer, and one last opportunity to see a large anaconda as we travel down the Tiputini River.
Week 7 (7/22-7/28)
The goal of this rotation was to play catch-up to try and match the number of snakes I got on the last stretch of TBS surveys, which will be very hard to do. Before this week, I only had 6 survey snakes at YRS compared to 28 at TBS. However, I am now only 16 away from meeting that goal, so while it is still tough, it isn't impossible. I think I'm just here at a really good time because the rainy season has finished up, and I am starting to see a large emergence movement of the snakes. Though catching up on surveys will be tough, my opportunistic encounter datapoints here are so much better. I got another anaconda on this rotation, thanks to he help from some herpetologists passing through the station. That must have been a Boidae-filled day, as I also got an enormous Amazon Tree Boa on that night survey. While the station itself has less biodiversity, I definitely enjoy the larger snake species that are here. I also have been getting a decent amount of colubrids, or non-venomous, non-mammal eating snakes, which isn't quite what I expected. However, the diversity in this group is still significantly lower. I will admit I have gotten lazier with inputting my data on the computer, especially for the frogs, because it is just so tedious and I have so many frogs. I figure I'll just wait until I have the study fully wrapped up and then I can do a mass copy off the GPS device instead of entering them by hand one by one. I've still got one week to do 5 surveys, and I really want to see at least one more species of boa and a viper before I leave this jungle.
In terms of my mentor's project, it has not been difficult so far, but this is also out of my control. We have been having trouble finding any fruiting trees at all, and without seeds, we cannot set up exclosure plots. If we can find some seeds, the tasks will get a lot harder. Most of what I have been doing so far has been pesticide reapplication and taking data on existing plots. I think we will get some sites set up, but probably not 5 clusters in each zone. I think this was a good week to sort of decompress and rest a little more after the difficulty towards the middle of the last TBS rotation.
Week 8 (7/29-8/04)
Well, I didn't exactly match the number of surveyed snakes at each site. However, I only ended up being 6 short here at YRS, and I am very happy with that. At the start of this week, I found my favorite snake I've ever seen in person: the Emerald Tree Boa. The adults don't usually It was all the best things I could hope for for my project. A Boidae, a mammal eater, and a super stunning animal in general. When I was a kid, I used to always read this children's book called Verdi. It was about a young Emerald Tree Boa who was afraid of aging. Juveniles of this species are a bright yellow-orange color and are more active. Verdi feared getting old and green because the green adults did nothing but but lounge around in the trees all day and eat every now and then. He ends up abandoning everyone to try and escape the passage of time, yet he still finds himself changing color and losing energy every day. Eventually, once he is old enough to be fully green all over, he runs back into the adults of the canopy. He realizes that maybe the lifestyle of lounging about in the trees may not be so bad after all, and he learns to appreciate his new green look. like to think that the individual I found, being a new subadult, was a snake like Verdi. An animal that was in the middle of figuring things out. An animal about to reluctantly head up to the canopy to live out its days curled up in the trees, waiting for the occasional rat or mouse to scurry by. An animal taking in the scenery of the understory one last time, in the perfect ambush position for me to find it. This was really a full-circle moment for me, and I can't think of a better snake to have found right at the end of the trip. Many late nights and countless effort hours have all been worth it.
My (ambitious) goal before coming was to get 80 snakes combined through all three detection methods for the whole field season. At the end of the final survey, I was standing at 99. I couldn't believe it, and was ecstatic to break my tough target by 19 individuals. 99 is a weird number though, and I felt like I just had to hit 100 by that point. I scoured the campsite for one more snake, but was only seeing the same old Helicops that I had become acquainted with over the past couple weeks. In one final effort, I walked the dry canal basin towards the lab to retire not only for the evening, but for the whole trip. About halfway down, I got it. A Ribbon Coralsnake sat curled up right where I had just placed my left foot. Not only was this a new species, but this put me at 100 snakes total for the project. I really can't say I have any regrets for how I set up my first independent project, and am looking forward to learning more about experimental design for future research. And with that, the summer '24 field season comes to a close.
