Selecting the best or most appropriate finding aid for identifying sources depends almost entirely on the context of your research assignment. There is no single database or web search interface that will work for every research context; instead, you'll need to match your specific research needs to a variety of options.
Library catalog searches (i.e., Primo) can be the better choice when you are seeking in-depth, book-length treatments of a topic.
Multidisciplinary databases (i.e., JSTOR) cover a wide variety of subject areas and may include a mix of popular and scholarly sources. They can be the most appropriate choice when you just want to get a sense of what's available on a topic and when it isn't so important that you pay attention to disciplinary lenses.
Subject databases (i.e., MLA International Bibliography) cover a specific discipline and provide the widest range of access to scholarly sources. They are used for in-depth research. Which subject databases you search will be determined by who may be writing about your topic. Recommended subject databases for each discipline can be found on the "articles" tab in each library subject guide.
Books in Primo are assigned Library of Congress Subject Headings. In many ways, subject headings are a form of tagging, in that they represent the content of the material and provide ways for you to efficiently locate more materials that are conceptually related.
Here are several examples of the various ways you can use LCSH to help pinpoint what you need:
Environmentalism in literature
Human ecology -- United States -- History
Nature -- Effect of human beings on -- United States -- History
A sampling of potentially relevant books is listed below. Some titles available in print and in online format.
Keep in mind - it is not usually necessary to read a book from cover to cover to engage with the author's argument. Instead, you may focus on a particular chapter or use the index to find parts most relevant to your needs.
Braiding Sweetgrass: indigenous wisdom, scientific knowledge and the teachings of plants by 
The Green Studies Reader by 
Human Ecology: how nature and culture shape our world by 
Living in the Anthropocene: Earth in the age of humans by 
Dancing with Disaster: Environmental Histories, Narratives, and Ethics for Perilous Times by 
Black Faces, White Spaces: Reimagining the Relationship of African Americans to the Great Outdoors by 
This Radical Land: a natural history of American dissent by 
Wilderness and the American Mind by Collins Library uses the Library of Congress classification scheme to organize books on the shelves. Follow these tips to find the book you need.
Example:
Use the library location chart and map to find where the book is located.
If you're not sure yet what you're interested in, or you're interested in so many different aspects of the environment that you can't decide where to focus, you might want to browse through scholarly journals to see what catches your eye. Collins Library provides access to several relevant scholarly journals, including those listed below.
These subject databases may be especially useful for your research projects for this class. Depending on your topic and your angle, you may wish to search additional subject databases.