There shall be a 7-member Conservation Commission appointed by the Board of Selectmen on a rotating basis of 2 or 3 members each year for 3-year terms. Associate members may be appointed by the Board of Selectmen each year to 1-year terms as non-voting members. The Conservation Commission's duties and authority shall include, but shall not be limited to, those specified in M.G.L. ch. 40, § 8C and ch. 131, § 40.