How much space for species?

I went to a talk last night on amphibian migration and woodland/vernal pools. The state is trying to set up a volunteer system to help amphibians at road crossings on the Big Night. Anyway, the speaker was talking about the space needed around vernal ponds. She said that there should only be a small amount of development within 100' of a vernal pond and a different percent 750' around the pond. (I didn't manage to remember the percentages). 750 feet, she said, comes out to about 40 acres necessary around a vernal pond. I am wondering what people think would be the amount of space needed to support a population of, for ex., tiger salamanders. I know that they are pretty much extirpated in NYS but I keep imagining there must be unknown pockets somewhere out there.

The talk was really interesting but I cringed and had to hold my tongue when they asked her the difference between a salamander and a newt and she said, "A newt's skin is more grainy." I didn't want to contradict/embarass her.

I just got a couple papers (one a thesis actually) that addressed this topic with regard to the striped newt. This one also references a number of sources which are directly related to your questions, and which you can likely find online or obtain from a library:
http://fl.biology.usgs.gov/Alytes_2003_21_1-2_3-22_Johnson.pdf

I think that there is more to it than how much space is available to support the population. Mole salamanders are dependent on the seasonal flooding of vernal pools. I have seen instances of vernal pools drying up do to distant construction redirecting the water flow. Its unfortunate that much of our construction redirects run-off to sewers and creeks, you can give them all the space in the world but if vernal pools don't fill there is no breeding.