Developing Testable Hypotheses of Anthropogenic Stress: Some Approaches That Work

Abstract

Conservation Paleobiology (CPB) has many aims, but ultimately depends upon our uncovering, for a target region, the history of environmental pressures and history of biological change, particularly biological change that signifies a response to anthropogenic stress: this is how we detect and correctly attribute deterioration, how we design and evaluate recovery, and how we ultimately assess resilience and sustainability. The focus of concern might be a single taxon of economic or other particular value, or larger-scale changes in biomass, taxonomic or phylogenetic diversity, or trophic complexity. One of the biggest challenges for natural scientists can be building the requisite history of cultural stressors – i.e., uncovering the diverse economic, industrial, social, and regulatory activities that might have affected the system. Such information is commonly not accessible via the Web of Science; it can be extremely important but qualitative or can be quantitative but highly variable in units or methods of measurement; and, with the exception of data on commercial harvesting (e.g., fishing, logging) and human population size, useful time-series are scarce. The CPB scientist thus typically needs to compile their own, original history of human activities having potential to affect natural systems, either to evaluate the (paleo)biological data that they already have on hand (from biomonitoring, live-dead analysis, sedimentary cores) or to frame a new campaign of data collection. Here, I describe approaches to finding and merging cultural data that have worked both for research and for class projects, using two coastal marine examples: (1) testing the effects of historical over-fishing (meta-analyses from the early 2000s), and (2) the unexpected role of land-use in the collapse of the open-shelf benthic ecosystem of southern California.