For some reason my last comment was removed...? This may be an error, but i can send you what i said:
Basically, you are not very specific with what you are trying to say. "What was the first species in a area" - is not very specific. However, i am going to assume that you are talking about Primary Succession.
The definition of Primary Succession is: "Primary Succession is an environment in which new substrate devoid of vegetation and other organisms usually lacking soil, such as a lava flow or area left from retreated glacier, is deposited."
It is basically how you describe the first / new life into an area. I hope this helps. Please be more specific next time tho.