Trends through the cycles: Reconstructing baseline population sizes from historical hunting records

Background/Question/Methods

The majority of good quality data on species population trends tend to cover the period 1970-present. Using this time period as a baseline for conservation assessments excludes many of the major anthropogenic impacts on earth’s species, and can obscure the distinction between population fluctuations and genuine recovery or decline. Historical, archaeological and paleontological records represent an underused resource in ecology and conservation. Here we show how methods developed for marine population estimation from catch data can be adapted to generate historical baselines for hunted species based on archival fur trade records. We use fur sale records from the Hudson's Bay Company to parameterize population models spanning multiple centuries for Canadian mammals. 

Results/Conclusions

We develop historical baselines and long-term trends in populations for a selection of hunted species. We show that historic records for the Canada lynx, made famous in documenting a classic population cycle, further suggest that amid this cycling, populations have fallen approximately 5% from the 1730s. For black bears and polar bears, results show large-scale population declines and an extension to current understanding of a population baseline by 250 years. These extended baselines add to our collective understanding of long-term population dynamics and can facilitate the identification of natural or human-induced drivers of long-term population change. They also enable testable predictions to infer future species abundances under varying regimes of management and global change.