Sci fi -read in 1990

I wonder if someone could help me locate this book. It is set on an alien planet. There is another alien race called the "parahuans" or similiar who are trying to take over stealthily. The hero is a young woman who uses her knowledge of the local flora and fauna to thwart their plans.

Thanks!

Google suggests The Demon Breed by James Schmitz. Apparently it's also known as The Tuvela and it is a novel in the Hub Universe series.

Wow! Thank you, that was quick. I just looked at the book online. It appears to be exactly the one I was looking for. I'm impressed.