This Fall will be remote for the majority of academic activities. The 8.0 credit honours thesis program is approximately 8mos in duration. The student leads an independent research project. As a team, we would like to work with two individuals on one of the following projects. Each student will work with a graduate student or postdoc and Chris Lortie.
a. Each project is individually implemented by the student safely. b. Zoom calls with Chris and the co-mentor to ideate, solve, and plan will be used to collaborate in addition to editing datasheets and docs. c. It will be beneficial for the student to have experience in R and be able to work independently. d. The pre-reqs are listed online for BIOL4000 are here and currently include students their final year with a BIOL GPA of at least 6.0.
Tree forest dynamics at YorkU
(1)Subway effects on trees and woodlots. A census of tree forest dynamics and individual tree changes on YorkU campus. Jenna Braun, Mike Belanger, and I dug through census records compiled by the YorkU master gardener in 2012 and 2013. Over 5000 trees were tagged on campus and their size and health were recorded. The data are here. This is a fantastic project and opportunity to revisit a superb dataset in R and also resample some or many of the trees. We now have a subway rumbling away underneath campus, and we can check trees near and far from the line and test the hypothesis that disturbance belowground influences tree growth and health.
(2) Other ecological hypotheses relevant to urban forest dynamics (disturbance, new buildings, edge or center of campus etc). There are at least two projects here. The students can work independently and still split up the work of testing more than question or hypothesis. One individual can (re)sample trees from 2012 and 2013 near/far subway lines, and a second student can examine any other ecological question with disturbance, new buildings, or how sets of trees are doing in different ecological contexts on a university campus.
Desert ecology data analyses
We have many open datasets ready to go for deep analysis work if you are competent in R (or Python but we work in R in the lab). Many spatial questions, niche questions, or use or plant and animal survey data and join them to new data on climate or downscaled remote data if you are game for that adventure. Here are a few examples.
Vegetation under shrubs and in the open in the Central California Deserts. Data.
Desert arthropod diversity patterns in California. Data.
Observations on accessibility of evidence and coherence in reported findings
In collaboratively writing this week as a team and in reviewing the literature with a specific meta-question in mind (how best to present community ecology, today, for the specific papers we are working on), we have a formula for a REALLY solid and clear presentation of results for some papers to consider – primarily for those that examined the response of a community (animals, birds, pollinators, etc.) to a key factor such as shrubs, shelters, water, light, or density to name a few ideas. This trend in reporting included competition and facilitation papers not just keystone plant species effects on other species.
FIG 1. Gift to the reader.
Surprise, this is for you. Thank you for getting this far into the paper or even scrolling to a figure. No sarcasm here – everyone busy and there a lot of potential papers to read in ecology and evolution.
This figure is thus the MAIN POINT of paper. Show them the hypothesis ‘worked’! We defined ‘worked’ as including enough complexity to address how well and when (i.e. community response by phylum or season). So, reading a paper on light and competition on COMMUNITIES (plants or any taxa), we skim to the first figure and EXPECT to see, well you guessed it, light on x-axis then y-some measure of how the community responded – big picture results. We also expected to see some facet or color in data or some level illustrating how well the factor worked so to speak. Is light level always important? Or, does it depend on something? Almost ALL current papers include that second factor.
The reader is like ‘OH I got it’. Density is important or microhabitat important, but it depends on season because birds fly around a lot and migrate too.
FIG 2. Show something about the species in community.
Imagine a reviewer for a journal such as Journal of Animal Ecology or really any eco-journal. The editor will try for an ecologist that knows something about desert mammals, birds, or the bees if the paper is about those communities. These readers will expect a second plot to be about composition or show species. Bird people (plant people too when we read community response papers about plants) want to be able see a plot and go OHYA I know that species OR aha I suspected NOT all species responded the exact same way to this key driver.
There are least three options for a STRONG second plot about species.
a. Relative frequencies. A stacked bar or line plot or something that lists out species and shows their relative frequencies by at least one, prefereably two, key level(s). Rank abundance plots nice but not so common now.
b. A composition plot from an ordination analysis One that shows something really deep about community OR actually shows species in the ordination plots with labels.
c. A cool species network plot A plot that shows not only the species BUT how their connections changes based on the key factor(s).
FIG 3. Mechanism or other key ecological context that illuminates WHY the community responded to key factor(s).
Optional (and depends on study of course) but can illustrate how another key moderator IF needed such as RDM, temperature, etc mediates the community outcomes. OR, show the mechanism that explains fig 1 and 2. OR, zoom in on a key finding such as species by functional group, migratory status, etc.
Fig 1 – Main finding with enough detail to encompass predictions or how well and when hypothesis works (or not). Fig 2 – Show composition or species because this is a community response paper. Fig 3 – Show mechanism, zoom in on how community responded (functional groups), or show a really important finding that is strongly related to Fig 1 but you did not want clutter up or make it even more complex.
Disclaimer Preferences from a week of work on reading and writing with an attempted laser-beam focus.
As a team, we are discussing the fine-scale grain of sampling for estimating annual-annual plant interactions in deserts. We are particularly interested in the Mojave Desert to examine pollinator-herbivore interactions with annuals that are mediated by the other immediately adjacent congeneric species. Here is a brief compilation of key papers examining this challenge.
Publications describing the fine-scale annual plant neighbourhood concept
In collaboration with Professor Katie O’Meara, an architect, Professor Zaitchik, an Earth Scientist, and researcher Claire Moriarty, we are examining the use of drones to map keystone species in extreme environments such as cushion plants in Patagonia or shrubs in deserts. This is just a pilot experiment (haha, get it), and we need a graduate student for 2020 to dig in and ground-truth the metrics we will derive from imagery. The focus will be structure and architecture in natural systems.
All field scientists know that getting out into nature to do your work means problem solving. Usually, you have to do this on the fly and with limited time, internet, communication… limited everything basically. But that’s where the creativity and decision making skills come in handy. Sometimes it’s a simple obstacle like breaking your tape measure or cactus spines lodged in your shoes. But then other times, it’s a seemingly catastrophic event—like flash floods destroying your study species, or political unrest in your study area—that disrupts your plan. Or, if you’re me, cold weather delaying cactus blooming in a cactus flower experiment.
This winter in the Mojave was unusually cold and rainy. The average high in January 2019 was 10.5°F—normally it’s a high of 57°F. Rain is great for flowers, it means there will be much more of them when they bloom. But cold means delayed blooms. And this Spring, it was delayed by about a month. Four weeks was how long I had planned to be in the desert, so after about two weeks of no flowers and a chilly forecast, I knew we needed to come up with some solutions.
The most obvious: stay longer. Duh. But this wouldn’t help if the cacti never bloomed, and I had to be back in Toronto to TA eventually. So I planned to hang out in the desert (no complaints here, it’s beautiful out there), but I knew we needed more options. Hire help? Working with birds means access to a large pool of citizen scientists who would give their time to look at birds in a place they otherwise couldn’t go. And I could hire a paid assistant from the area. These two options seemed great, but getting anything done with the public takes several months advanced notice, and there simply wasn’t any interest in my for-hire ad. So help was out. I kept thinking, and waiting, and hoping the flowers would just bloom and I could work extra long days and get it done. But that didn’t happen.
I had one last idea. Perhaps it was my most hair-brained scheme: use fake flowers (more appropriately called mimic flowers). After all, the problem was there were no flowers, and the end goal was to have flowers. A few papers had studied bird (hummingbird, specifically) visits to mimic flowers, and had success. This idea, which we didn’t know would even work, required a lot of experimental design rewiring. Two semester’s worth of planning and design scrapped and reinvented in a hour was terrifying. Whoever I told about my woes all echoed the same reaction, “That’s field ecology for you!” For a worrier and a planner like me, it’s a nerve-wracking line of work.
But I had to do something. I’d finished walking transects to look at birds and needed to start an experiment, any experiment. So I bought a bunch of fake flowers at Michael’s (Michael’s, would you like to sponsor an up-and-coming ecologist??) that looked like the Buckhorn Cholla’s flowers I’d seen on google, and pinned them onto the un-opened buds of my focal cacti. I had four levels of manipulations, set out camera traps, and watched for an hour. I was on the edge of my camping-chair-seat for the first session. There were thirty flowers pinned on this plant, my highest volume of flowers. Would they come? I needed proof of concept, proof that the birds would visit these cacti in some capacity, or else my findings are nothing but “birds don’t visit cacti”. Nothing wrong with this from a scientific perspective, but there’s not much to explore after the fact. A huge part of my Master’s relied on this next hour.
I was lucky. Within seven minutes, a Costa’s Hummingbird visited the cactus and attempted to pollinate the fake flowers. And then 6 more did the same over that hour. Funnily enough, this would be my busiest session for the rest of the field season. But it was peace of mind—the birds came, and no matter what else happened for the rest of the Spring, I had something to compare all my results to. After the 10 day experiment observing these mimic flowers, they finally began to bloom. The flowers really did look similar to the mimics, and I figured next we could see how different concentrations of real flowers on a cactus influenced bird behavior.
The experimental design for the real flowers was exactly the same as the mimic flowers, but this time, there were real flowers on the plants instead of fake ones. So I watched and waited, this time with less anxiety. But the first day passed, and no birds visited the cacti. Strange, but it was a particularly hot day, perhaps they just weren’t out and about. The next day came and went, and still, no birds at the cacti. This stayed true for the rest of the experiment. Birds were still coming to the procedural control (a poll with 30 mimic flowers glued to the top), but not to the real flowers. Not even once in the 10 day experiment. And just like that, the experiment ended. Science waits for no one.
Now, I’m back in Toronto. Data analysis is next up on the docket, but one thing is clear even without the statistics: birds will pollinate flowers on a cactus, just not the flowers that a cactus actually produces. It’s not the entire structure of the cactus that deters birds, but something about the flower itself that tells them not to come.
We know that most cacti are primarily pollinated by bees, and now we can say, at least for Buckhorn Cholla, they are absolutely not pollinated by birds. Could the flower have ultraviolet patterns advertising to the birds that this flower is not for them? Or perhaps a chemical signal from the flower deters them? Essentially, what is the mechanism associated with the flower that keeps birds away?
But perhaps even more interesting is this: what is the cactus flower actually saying to different pollinators? Two signal options exists, exclusionary or inclusionary. The flowers may signal that birds should not come here. Or perhaps, the flowers signal that the nectar is explicitly for bees. Imagine a sign outside a young boys treehouse saying, “No girls allowed.” This is an exclusionary signal, telling girls that they cannot come in (but I mean, smash the patriarchy). Now consider a “Man Cave” sign outside a basement. This is an inclusionary signal, suggesting that this space is for men. In the end, these signs have the same outcome: no women are in the space. An observer who cannot read English could observe that no women entered either of these spaces, but would need to be able to interpret the signs to know whether the signal is exclusionary or inclusionary.
This is fascinating, because in our human signage example, the interaction individuals of men, women, and sign-maker all are the same species speaking the same language. But in our bird-bee-cactus scenerio, we have three extremely different taxa (a plant, an insect, and a vertebrate) all possibly “reading” the same language. And they do all this interspecific signalling avoid niche overlap and wasted energy.
Now, we just got to test it. Easier said than done.
All these questions were… not what I was expecting to come home with at the start of my field season. Had the flowers bloomed when I arrived, I would have performed our original experiment manipulating the number of flowers on different sized cacti. And I would’ve gotten a whole lot of nothing. I’m a scientist, so I don’t like to say fate had a hand in this, but it was some good luck that I was so unlucky.