Complex sentence: Party members then joined the Alberta Conservative Party, and the Provincial Rights Party in Saskatchewan, and a lot more members including MLAs defected to the Alberta Liberal Party and Saskatchewan Liberal Party, draining the Conservative parties of man power and experienced politicians.
Split into simpler sentences: Party members then joined the Alberta Conservative Party, and the Provincial Rights Party in Saskatchewan. Many members, including some Members of the Legislative Assembly (MLAs) defected to the Alberta Liberal Party and Saskatchewan Liberal Party, draining the Conservative parties of man power and experienced politicians.