Pitfalls and possibilities: Aggregating data for coarse scale replicates in time and space

Background/Question/Methods

Forecasting the response of species and communities to environmental change is a priority for multiple disciplines in the natural sciences. In looking towards the future, much can be learned from examining faunal response under past episodes of environmental change. Retrospective studies can take many forms and span a range of spatial and temporal scales. This talk will focus on the use of data from natural history collections as archives of baseline ecological information at decadal to centennial time scales. When paired with modern resurveys, these historical data can provide critical insights into recent ecological changes. Examples will be primarily drawn from an ongoing resurvey project on the small mammal fauna of the Great Basin of western North America. Because species-specific life histories and ecological requirements render small mammals sensitive to changes in both climate and vegetation they can be powerful indicators of changing environments and ecosystem health. Responses at both the species and community level will be presented. The approaches and concerns addressed are applicable across taxa and regions.

Results/Conclusions

This talk will highlight the challenges associated with the use of historical data, in particular, data completeness and spatial uncertainty. Because modern-day resurvey efforts simultaneously establish new baseline conditions which can be used for continued and future monitoring, practices for minimizing these concerns moving forward also will be addressed. Emphasis will be placed on (1) the confounding effects of land use and climate in discerning benchmark conditions, and (2) the need for the definition of replication and resurvey to go beyond the local scale and recognize the benefits of aggregating data over broad spatial and temporal domains. Overall, I will argue that the utility of any one retrospective approach for conservation and management is limited, and that it is necessary to integrate retrospective approaches across spatial and temporal scales to develop informative generalizations about patterns of faunal response to environmental change and the processes that underlie those patterns.