What are the main practical complications/challenges to using Linux as your full time OS, particularly as faculty in Biology/Ecology?
This question might well be closed as off-topic, but here is my experience as a mathematics professor who has used Linux on his primary desktop machine at work (and on my computer at home and on my personal laptop) for 20 years.  Before that I ran Solaris on Sun workstations.  Before my academic career, I worked as a Unix system administrator in the 1980s, so I had a lot of background.  


Your IT department might be unwilling to allow you to run Linux on a university-owned computer and might be unwilling to allow you to connect your personally-owned Linux machine to the campus network.
You may be required to purchase university-owned computers from a particular vendor whose hardware might not work well with Linux.
Your institution might require you to use specific software that only runs on Windows.  For example, earlier versions of the widely used Banner ERP system couldn't be used in Linux. I used to have to authorize purchases that were made with my department's purchasing cards using a Windows only software package (actually a web app that required Internet Explorer 6 and wouldn't work with Firefox or Chrome.)    
You may have trouble interchanging MS Word Documents or Excel spreadsheets with Windows users (Libreoffice is pretty good but still not perfect.)  
You may not be able to use licensed software (such as SAS, MATLAB, etc.) that the university has site licensed for Windows.
Your students and colleagues will probably be using Windows machines and you won't have an environment that perfectly duplicates their setup.  This can make it difficult to reproduce problems that they have, even with free software.  For example, I recently had an issue using Octave (an open-source MATLAB like language.)  My code ran fine in Octave under Linux but failed in Octave under Windows when a colleague used it.  This turned out to be due to a bug in the math library that was used on the Windows build of Octave.   
Your IT department will almost certainly not provide any support for problems that you might have with your Linux system- you'll be on your own to resolve any issues that come up.


I've always made sure to maintain access to a Windows machine for this few times when I really need it, but in recent years that's been extremely rare.   I've got a university-owned Windows laptop that I haven't powered up since July, and I don't miss it.  Despite dealing with many of the issues above, I've had a very good experience using Linux and wouldn't consider switching back.