preserve是保护、保持,其含义是让对象维持原状,自由发展.
If you preserve a situation or condition,you make sure that it remains as it is,and does not change or end.
defend是保护、防卫,其含义是用行动来保护对象不受敌人侵害.
If you defend someone or something,you take action in order to protect them.
对于部落文化,应该是保护保存,所以用preserve.