class ic ▁periods ▁( ca . ▁ 3 5 0 ▁B CE ▁- ▁CE ▁ 1 5 0 ), ▁with ▁relatively ▁little ▁over bur den ▁from ▁the ▁large ▁scale ▁constru ctions ▁and ▁extensive ▁settlement s ▁that ▁character ized ▁the ▁Classic ▁periods ▁( CE ▁ 2 5 0 - 9 0 0 ) ▁of ▁Low land ▁May a ▁civil ization . ▁ ▁Il legal ▁logging ▁and ▁forest ▁fires ▁resulting ▁from ▁slash ▁and ▁burn ▁agricult ural ▁practices ▁threaten ▁Mir ador ▁Bas in ' s ▁rich ▁b iod iversity . ▁L oot ing ▁is ▁also ▁a ▁major ▁threat ▁to ▁the ▁many ▁May an ▁arch ae ological ▁sites ▁that ▁res ide ▁in ▁the ▁Bas in . ▁While ▁many ▁sites ▁are ▁known , ▁others ▁remain ▁und isc over ed ▁and , ▁according ▁to ▁Richard ▁Hans en , ▁" by ▁the ▁time ▁sch ol ars ▁get ▁there , ▁lo ot ers ▁may ▁already ▁have ▁pl under ed ▁them ." ▁ ▁The ▁region ▁belongs ▁to ▁the ▁May a ▁B ios phere ▁Reserve ▁that ▁represents ▁the ▁last ▁large ▁area ▁of ▁int act ▁tropical ▁rain for est ▁remaining ▁in ▁Mes o amer ica . ▁Arch ae ological ▁and ▁environmental ▁studies ▁conducted ▁by ▁the ▁Mir ador ▁Bas in ▁Project , ▁directed ▁by ▁Richard ▁Hans en , ▁previously ▁known ▁as ▁the ▁Regional ▁Arch ae ological ▁Investig ation ▁of ▁the ▁North ▁Pet én , ▁Gu atem ala ▁( RA IN PE G ) ▁Project , ▁have ▁identified ▁data ▁relevant ▁to ▁the ▁orig ins ▁and ▁early ▁development ▁of ▁the ▁May a ▁civil ization ▁in ▁this ▁area