Conservation of rare species

The fact that most species are naturally rare creates a dilemma for conservation authorities. It is generally understood that risk of extinction tends to increase as population size declines. On the other hand, attempting to conserve hundreds of rare species would have potential to spread resources too broadly.

A thoughtful discussion of this dilemma and related topics is presented in a paper titled “Understanding rarity: A review of recent conceptual advances and implications for conservation of rare species” (The Forestry Chronicle 88 (2): 165-175). The authors are C.R. Drever (The Nature Conservancy), M.C. Drever (University of British Columbia) and D.J.H. Sleep (NCASI). The abstract follows.

“Rare species carry a connotation of uniqueness, of being especially valuable, and of heightened extinction risk. We review the literature regarding rare species and link rarity and risk concepts to jurisdictional rarity and how to allocate conservation efforts to rare species gone long undetected. Conservation actions for rare species should be prioritized based on best available information of population trends and thresholds of minimum viable population or geographic range size.  For species rare in some geopolitical jurisdictions but common elsewhere, we recommend prioritizing conservation action by assessing beyond jurisdictional boundaries to assess stewardship responsibility relative to the global distribution and at-risk status of the species in question. For making the thorny decision about when to stop managing or monitoring a long-undetected rare species, it may be optimal to continue conservation efforts for a long time, especially if the species has considerable social, economic or ecological value. Recent advances based on theories of optimality provide a replicable and transparent process upon which these decisions can be based.”


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