An understanding of how past conditions have shaped present-day ecological patterns and trends is critical to science-based conservation management. Unfortunately, the records, specimens, and objects historical ecologists need to help generate that understanding are often lacking. And because of a general underinvestment by society in systematic collection and museum curation, future historical ecologists may be similarly limited in their ability to investigate conditions regarding our present day. Given the importance of historical data and materials in contemporary conservation decision-making, we suggest it is incumbent upon resource managers and scientists to ask whether additional research efforts are needed to document past and present conditions of the places and resources of their interest. Here, we discuss how such an inquiry was applied to the terrestrial and nearshore environments of Santa Cruz Island, California, USA. The island harbors numerous endemic taxa, important archaeological and fossil sites, and rich cultural significance. It also has undergone dramatic and ongoing alteration due to past and present human activities. We describe an interdisciplinary effort to identify information gaps regarding past and present conditions of the island. In many cases, filling those gaps will require a research focus on a broader geography and suite of resources, including the archipelago in which the island sits and mainland “sister sites.” An initiative to improve collection and retention of priority information could be a basis of interdisciplinary and multi-institutional collaboration and could be designed to foster environmental education and citizen science programs that engage the next generation of conservationists. An outcome of this initiative would be an archive of materials and data to inform the historical ecologists and conservationists of the future, and to help conservationists today ensure that the resources they deem most important will be stewarded successfully into that future.