One of the most powerful approaches for understanding biological invasions by non-native species is to examine ecological patterns and processes in both the native and non-native ranges of invasive species. Here’s a great article on the subject:
The number of articles published on biological invasions has increased exponentially over the last 20 years, but biogeographically explicit studies replicated in the native and non-native ranges of invasive species are still VERY rare. This hampers our mechanistic understanding of the invasion process and therefore our ability to explain, predict, and manage biological invasions.
Bromus rubens (i.e., red brome) invasion in the Mojave Desert provides a great opportunity to address this knowledge gap. We are planning to examine the individual and joint effects of shrub facilitation and post-dispersal seed predation on the abundance of B. rubens in its native (Israel) and non-native (California and Nevada) ranges. This experiment is broadly interesting because it allows us to test the relative importance of the effects of two fundamental biotic interactions on two continents. Here’s a cartoon of our experimental design:
Solid circles represent functional exclosures that effectively exclude seed predators; dashed circles represent non-functional exclosures that admit seed predators. Note the control treatment that monitors recruitment from seed banks. This is a full-factorial design that crosses shrub facilitation (open vs. shrub microsites) with seed predation (functional vs. non-functional exclosures). Pretty cool.
We will replicate this setup at 5 shrub-open pairs per site at 6 sites across the Mojave (GPS coordinates are preliminary):
We will replicate the experiment at 5 sites in the Negev Desert of Israel with the help of Dr. Merav Seifan of the Ben Gurion University of the Negev. She rocks! Site locations and GPS coordinates in Israel are forthcoming.
The biogeographic contrast of the effects of seed predation can be considered a test of the enemy release hypothesis, which has only been examined once in the context of seed predation:
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.
York Science Fellow Dr. Jacob Lucero and international collaborator Dr Merav Seifan are launching into 2020 with an ambitious experiment in Israel and California. The purpose is to explore the relative importance of provenance of a highly invasive species of bromus in the deserts of California by comparing performance and key interactions in its home range, Israel, and in its introduced range, California. This is a new direction from previous work published in NeoBiota entitled ‘The dark side of facilitation: native shrubs facilitate exotic annuals more strongly than native annuals’ that demonstrated a very significant effect of bromus on local plant community dynamics.
Sometimes, peer review (and procrastination) help. Other times, the delays generate more net work. I was discussing this workflow with a colleague regarding a paper that was submitted two-years ago, rejected, then we both ran out of steam. This was the gold-standard workflow we proposed (versus reformat and submit to another journal immediately).
Hit web of science and check for new papers on topic.
Download the pdfs.
Think about what to cite or add.
Add citations and rebuild biblio.
Update writing to mention new citations especially if they are really relevant (intro and discussion).
Take whatever pearls of wisdom you can from rejection in first place and revise ideas, plots, or stats.
Format for new journal.
Check requirements for that journal.
Search the table of contents for the journal and check your lit cited to ensure you cite a few papers from that journal – if not, assess whether that the right journal for this contribution.
Download pdfs from new journal, read, cite, and interpret.
Then, look up referees and emails.
Write cover letter.
Set up account for that new and different annoying journal system – register and wait.
Fight with system to submit and complete all the little boxes/fields.
3D printing may seem like a hyper-modern, futuristic tool from Star Trek or Doctor Who. But the first comprehensive outline for the technique was described in 1974 (by David E. Jones), and was in practice at some manufacturing companies all throughout the 80’s. Most popularly, it’s a great way to design prototypes of complex machine parts that have unusual shapes. But now it’s a common technique for most inventors, as well as hobbyists who have small, affordable 3D printers at home. And in many cases, it’s available for a small, small cost at your local library with the help of tech experts.
The Printing Process
The printer’s function is important for all aspects of the project, from design, to printer settings, to finish. The project doesn’t just magically appear, but (most commonly) is created using “fused deposition modeling” (FDM). Essentially, this means that the printer melts the material, and squirts it out on a the printer bed. But it doesn’t just squirt out a whole product. It lays out a thin layer of plastic on the printer bed’s plane. After that layer is done, the printer prints another layer on top of it, repeating the process until the project has taken shape.
There are lots of parts to a printer, but I’ll lay out a few that will make further explanations easier to understand.
Print bed: the flat board that the material will land on. Think of as you bottom, or even x-axis and z-axis plane.
Hot end: the nozzle that the printing material will squirt out of once melted
Extruder: the chamber where the material is melted for printing
Filament: the plastic tube string that is the material for printing
Designing a Project
Designing your project is the most creative part of the process, and there are lots of platforms (free and not) to design on. I like to use TinkerCad, since it’s open source, online, and relatively user friendly. It’s great for hobbyists, or non professional designers, and it’s outputs are compatible with most printers we’ll run into. For a quick and comprehensive tutorial, check out this Tinkercad video.
Since the printing process is essentially layering plastic on itself, you can see why you can’t just print any sort of shape imaginable. The printing process relies on gravity, and each layer must print on something else. Sturdy, solid objects are generally easier to print than thin, flimsy ones. Sometimes this can be as easy as laying the object in a different way on your bed. For example, if I wanted to print something shaped like a pencil, it would be easier to lay the pencil on its side in the design than on it’s eraser. But that doesn’t mean we can’t get creative with our designs! I’ll explain how to get around the little problem of gravity later in the print prep section.
Here are some tips to keep in mind while designing that I came across.
Use the copy+paste option whenever there’s a repeating element. It saves so much time, and keeps things consistent.
When you use copy+paste, try and use the arrows on your computer to re-position the new element, especially if you want it to remain even to the original in at least 1 of the 3 planes (x, y, or z).
Group elements as you go, especially for repeated elements that might need a bit of adjusting as you go.
Keep gravity in mind! Floating objects will just fall to the ground in a clump when you actually try to print them.
Make sure different elements are securely connected. If elements are only barely touching, they’ll probably fall apart in real life.
You can only use one color when printing, but you can always paint your object afterwards if you like/have the time.
Think about material availability if you’re printing lots of copies. There won’t be endless filament, especially if you need them all to be the same color.
Export your project as .obj, and save onto a flash drive if you are going to print at the library.
Once you’ve designed your project in TinkerCad, you’ll take that file to the printer. For our group, we like to use the Toronto Public Library’s Fort York Branch. They have some great techs there that help with design, prep, and machine work, and the price is one 10 cents per gram (that is a steal). They have several brands of printers, and certain printers require certain software programs for you to prep your design in. All you need is a library card!
Prepping is the step when we make decisions about settings for the printing project. This includes things like layer size, supports, rafts, and other things specific to the printer in question. After you’ve personalized each setting, you’ll save that new file to an SD card, and insert that SD card into the machine itself. (At the library, the techs will help you with this part).
Basic settings will work for most projects, but as you get more advanced, it’s nice to have some options to optimize your printing. When changing settings, always take into account the print time (it can get very long if you’re not careful) and filament use (you don’t want to be wasting filament on extras you don’t really need).
When part of your design “overhangs” the previous layer, you can employs a printing strategy called supports. These are essentially buttresses that the program will insert for you once you are prepping your final print. These supports print underneath the project itself, and are removable (but be gentle when you snap them off!).
Rafts are another type of support, that are helpful when you have a project that needs a strong base. It prints a thin sheet of plastic that you’re design will be printed on. This makes your project a lot longer to print, but is necessary when the bottom of a project isn’t simple.
Layer size will determine the thickness of each printed layer. The thicker the layer, the coarser the design will be, so if you have a very detailed design, I would recommend making it a smaller layer size. However, smaller sizes take a lot longer to print, so if your design is a simple shape, keep if coarse.
3D Printing is Versatility
It’s not only printing objects themselves that 3D printing can be useful for. A common practice is printing molds of objects that you’d like to make copies of. This is a great option if you think you might need to make more in the field (when you don’t have access to a printer). Resin, plaster, rubber, and cement are all common mediums for mold making, and can be bought at most hardware stores.
3D printed objects are also great replacements for machine parts that have gone missing, or need customization. Need a new handle for your net? A back for your GPS unit? A special box for strangely shaped equipment? You can absolutely 3D print that! And on top of that, superglue works great with 3D printed materials, so you can print parts and combine later.
I got into 3D printing for creating mimics of cactus fruits, which are a strange shape that I can’t find in any shop (scientific or otherwise). So for experiments when you need a control for shapes (this is great for facilitation experiments), 3D printing your objects is an excellent option.
It may seem intimidating, but 3D printing is an accessible tool that can be learned in an afternoon. And you might even find yourself making some projects just for fun!
Bromus tectorum, one of North America’s most problematic invasive plant species, may owe at least part of its explosive success to escaping the effects of generalist consumers in the non-native range relative to the native range.