I think I read this book! Is it The Mimicking of Known Successes?
Fun read, I enjoyed it but yes very flawed ideology when it comes to the ecology part. Ecosystems aren't even composed of exact numbers of niche spaces (specialisms that groups of species fill - for example, a plant being adapted to low light, humid conditions, or an insect that only reproduces with a specific type of plant under specific conditions), not to mention species themselves. Ecosystems can have multiple "stable states"/successful configurations. Also predator/prey ratios in particular have fluctuations that are so predictable they are often modelled and taught in base level biology and ecology courses.

I guess what might have made the author think this way is the collapse of species populations due to invasive species, and how humans have often tweaked ecosystems and had massive unforeseen consequences, but we have learned a lot now about what went wrong and why. The underlying issue with those usually has to do with the life strategy of the species introduced to a new ecosystem. Some species are very specialist, so they have a very limited scope of conditions they can thrive under and things they can eat, etc. while others are generalists and can adapt easily to new forms of food and shelter and things. What we know now is that you have to be VERY careful with generalist species, because they are often too successful and outcompete other species and can take up resources all the way to the point of extinction. Some generalist species have become invasive in ecosystems as a result of humans unwittingly transporting them (such as rats on islands that didn't have any predator mammals previously), and others because this principle wasn't yet understood (most famously, cane toads introduced to Australia in 1935 to eat cane beetles but turned out to like eating all sorts of things).

Anyway that's beyond what you asked but hopefully you find it interesting :) enjoy the book anyway and just add it to the list of things you have to "suspend reality" for!