Motivation here is first because, as this area of scientific endeavor developed, some of first (at least) were really 'out there'. May become clear upon explanation. We could begin with Alexander von Humboldt. He pretty much originated the idea that distributions of plants and animals was a useful thing to study. But before rolling up his sleeves, he repeated some of Galvani's electrical-stimulation experiments, including on himself. Then he got down to business, but the electrical thing was still on his mind. Used (terminally) horses to discharge electric eels so they could be collected. Apparently Prius-battery-proof rubber gloves were unavailable? Here are a couple of homages to on-topic work of ecologist 1.0 Rocky Road: Alexander von Humboldt The Exquisite 19th-Century Infographics That Explained the History of the Natural World - Atlas Obscura
There is a tribe in South America that knows how to pick up electric eels bare handed. Guess he didn't meet them.
I have a list of other names to consider here. Yes, including C. Darwin. But before troubling readers with those, if you have any names in mind, let us know. For me the unifying theme is that people who devote most of their lives to ecology are something else besides. So, no unifying theme? Man oh man, I got tap dancers, model-train enthusiasts, solar physicists, diamond sellers, violinists, and more. Might be inappropriate to name names. But maybe there is a unifying theme. Maybe ecologists are people whose minds stretch out pretty far, and within that see ecology as a worthwhile aspect. Yours truly is quite far down the list and only here talking because Prius is one of my things. If this thread proves viable, I should expand what ecology is (interactions between organisms and environment) and decorate that with who ecologists are. Click-bait-wise I must say that when I signed on I had no idea what a bunch of wacky (interesting) folks I'd be dealing with.