Our paper is out in Freshwater Biology, looking at how consumer resource use changed following the 2013 floods in Colorado's Front Range. We found that insects relied more on low-quality detrital resources in the streams that had experienced more intense flooding, regardless of taxonomic or functional identity. You can read the paper here.
Our paper came out in Ecology Letters describing community and genomic changes in stream insects following the 2013 floods in Colorado's Front Range. You can read the paper here.
I had a great time chatting with Dr. Amanda Subalusky about her work on animal migrations and nutrient subsidies in the Mara River, Kenya.
Check out the podcast episode information here: freshwater-science.org/news/making-waves-ep-27
Or listen to the podcast on iTunes here: itunes.apple.com/us/podcast/making-waves-a-freshwater-science-podcast/id1314016715?mt=2#
Check out the latest episode of the Making Waves podcast here to learn more about how environmental DNA moves through streams. I had a great time talking with Arial Shogren about her work.
I've just completed a 3 month field season in the Napo basin in Ecuador. This year, we crammed a bunch of sampling into that short time, re-sampling stream communities for my annual sampling program, doing another round of the colonization experiment, and sampling for a new project I've started looking at how stream insects allocate their resources along a gradient of disturbance intensity and frequency.
I always love doing fieldwork, and it's especially awesome to return year after year to the same place to see how things change. Last year, it was amazing to see how landslides had changed our sampling sites, and this year it's been incredible to see the landscape start to recover.
At long last, it’s experiment time! So far, all of my work has been observational, which feels pretty typical for many grad students at the beginning of their dissertations, and I’m excited to be turning the corner into the big kid experimental world, with a pilot run of my experimental design.
[For those of you non-scientific method leaning folk, here’s why observations and experiments are such a good pair. First, observations let you establish a pattern – something real that’s happening in the natural world. You may be able to see some correlations with this data, like when X happens, Y also always seems to happen, but you’re not sure if X causes Y, Y causes X, Y causes Z, which causes X, or if X and Y only superficially appear related and actually behave independently. Sometimes fancy statistics help you dig deeper and further and say more about your data and what’s happening in your system, but experiments always remain the gold standard in ecology, since they let you start to unravel these causal pathways, and get at process.
So to recap, pattern + process = good science. I’m not knocking natural history, or working with large observational datasets to ask questions over huge spatial gradients that you couldn’t do experimentally, or anything like that, but so much cool science can happen at small spatial scales when you observe something in the natural world, and then poke and prod your system experimentally to see why you saw that pattern. ]
Anyways, colonization experiment! Basically, between my community observations and drift surveys this field season, I’m gathering data to continue to add to the dataset on how communities in Ecuador have changed along a stream stability gradient since our project began sampling them four years ago. I’m also looking at drift propensity differences among macroinvertebrate communities as a possible mechanism for these differences in community stability across sites. Now, at three of these sites, I’m testing how quickly and by whom (meaning macroinvertebrates and algae) cleaned substrate is colonized over time in the stream.
This all may sound like glamorous and fancy science, but so far it’s meant collecting and hauling around buckets of rocks from stream banks, scrubbing said rocks to remove any organic matter clinging onto them, baking them in the oven to be extremely sure that they are clean and free of organic material, then drawing on them with paint pens, measuring them and taking pictures from them, and then putting them back in the stream. Because this feels like work that a 5 year old would find fun, I rewarded myself at the end of rock collection day with hot chocolate and animal crackers.
I’ll keep putting 12 rocks out into each stream every two days and then collect them all at once on day 7 to quantify the algal and macroinvertebrates that have colonized each rock. Stay tuned for results!
Halfway through my second full field season in Ecuador! The halfway point of a field season always feels like the crux, when goals are starting to be achieved, and yet there's still so much to do. If a PhD is a marathon, then each field season is like another three mile chunk you have to get through on your way to the finish line.
So far this season, I've been resurveying stream sites that I surveyed last winter for macroinvertebrate communities, basal resources and physical habitat data. In the intervening time between my 2015 and 2016 surveys, huge landslides hit many of our study sites below 3000 meters in the Papallacta drainage here. See the photos below for an extreme example at Guango, one of our most disturbed sites. I'm interested to see how communities have rebounded from this disturbance, and subsequently to understand the mechanisms behind their response.
To better understand the mechanisms driving community recovery after landslides and floods, I'm doing a drift net study to quantify dispersal across my study streams, using some awesome drift nets that a fellow grad student helped me make. I'm also starting a pilot recolonization experiment in the coming weeks, so fingers crossed that this part of the field marathon goes smoothly.
Above: One of my high páramo study sites in the Río Chalpi drainage near Papallacta, Ecuador.
To bring you into the field with me, to share science that fascinates me, and to ponder the process of doing science. For more frequent updates, follow me on Twitter (@ernlarson)