For your research question, "What are the social benefits and liabilities for tribes developing casinos on Indian reservations?", the database that would be more likely to point you to articles relevant to your topic is sociological abstracts.
Sociological Abstracts focuses on sociology and social issues and would provide insights into the social impacts of casino development on tribal communities. On the other hand, Biological Abstracts would primarily cover topics in biology and life sciences, which would not be relevant to your research question.