When more surveying for rare species does not lead to more value for conservation planning

Background/Question/Methods

The assumption that collecting element occurrences records and updating the old improves conservation planning efforts may be unfounded if doing so only reinforces our current plans rather than indicating overlooked important places.

Here we explore how updating old and adding new element occurrence records changes the relative conservation priorities of sites. Using a database of rare species element occurrences in Tennessee, we temporally sub-sampled more than 18,000 unique occurrences. We initially defined the spatial distribution of species across Tennessee using an intentionally limited subset of 40 occurrences collected between 1900 and 1909. Then, year by year, we added new and updated occurrences to the database. In each year, we prioritized 938 watersheds according to species richness and measured the change in priorities over the previous year using Spearman’s ρ.

Results/Conclusions

Our preliminary results show that, as the database of records grows through time, the change in priorities decreases. This is true for not only richness, but also when we consider only the most rich sites, other conservation objectives, and data reliability through time.

In Tennessee, conservation priorities change less as we acquire new data, and not because we are adequately sampling sites. Tennessee's data collection history is likely representative of data collection elsewhere. As conservation planners, we should consider how we treat data in our prioritizations. If the goal of updating our priorities is to point out overlooked but important places, then following a methodology that is decreasingly changing our priorities may be flawed.