How can a high GRE score benefit me?

Most of these are questions you should be asking of your professors with a knowledge of Landscape Ecology. These thing are all very field dependent. You might want to consider also applying to fields more likely to provide funding in case you do not get into a department that does. "Can I join any interesting MENSA-like societies or anything? I know MENSA doesn't accept the GRE, but some of the high-IQ groups do - are any of them worth it?" Absolutely not

In my field (which is different than yours), we have one use for the GRE other than weeding applicants out. It's this: occasionally we'll have an applicant who looks really promising -- great writing sample and letters, e.g. -- but whose undergraduate career was checkered in some way. Maybe bad grades sophomore year, or withdrawing from school for a while, or something. They'll usually explain the checkered part, but the high GRE scores reassure us that it's the failures that were a fluke, not the success.

I got a very high GRE score last year. I think it helped my case a bit because I was changing fields to biology about ten years after I got my BA. (I also took postbac classes and did very well in those.) I'm not in a competitive niche, but I got in everywhere I applied, with RA funding, and I'm now enjoying a fellowship with some nice perks. Not sure it would help so much with grant-writing, as the focus is very much on the quality of your proposal. If you're interested in top-tier programs, email profs you want to work with and inquire (unless the program is specifically against that). I generally asked if they were taking students in the initial email, if they were they would then ask for my GPA/GRE and I could wow them. :) (Like ecsh, I also coast on my book-smarts to cover my less-awesome work ethic. There's a reason people believe the smart-but-lazy-stereotype).

Congratulations! If you checked the box on the GRE to get info from other grad schools -- it's one of the options that will put you on grad school mailing lists, but I can't remember how it's phrased -- it might get you offers for application fee waivers. They are a relatively small thing, but the fees do add up.

I have run Phd admission processes for nearly 20 years (humanities). We always say a certain score (esp. Verbal) is basically expected (I say around 650 for a native English speaker with no diagnosed LD issues). Above that it can help at the margin. Below that it raises doubts you can write a dissertation. However, in my long experience, perfect or near-perfect verbal scores are very common among the top group of applicants to top PhD programs in my field. So don't rest on it!

This isn't the case for you, but I know verbal GRE scores can be the deciding factor in admitting ESL students to humanities/social sciences programs.

High GRE scores (especially in conjunction with a strong GPA) are often a significant factor in obtaining fellowships from the graduate school (not the individual dept so much). I got strong scores (not quite as high as yours), and of the three schools I got into, one offered me an extra $3,000/year, and one offered me a teaching exemption for the first two years of my program. However, I should also note that a high quantitative score doesn't tend to mean as much as a high verbal score - something like 15% of test-takers get a perfect score on the quantitative section, as the maths involved is actually fairly basic. (As a corollary, that means that your verbal score is even more impressive, as only the top few percent break 700 on that.)

I'm in the same boat as hydropsyche, down to the EPA STAR. I remember that fellowship in particular looks at your transcript and GREs, and unlike others, provides feedback. I remember my feedback praised my high grades in quant/ecology courses and my GREs. Aim high with your applications. The most important thing is that you fit with a professor's research program (and that prof is taking students). This is why it helps if you know what you want to do!

My high GRE scores helped me get a merit-based fellowship for my MPH. I didn't quite meet the GPA requirement posted for the fellowship, but the department nominated me anyway and I was awarded it. Yay for standardized test taking skills.