What’s in a name? Proposed reinterpretation of key words in the Endangered Species Act

This post contributed by Sean Hoban, a post-doc in conservation biology at the University of Ferrara, Italy

The butternut (Juglans cinerea) is a rapidly disappearing tree species (left, healthy; right, devastated by disease). It is one example of many species whose potential future listing could be affected by definition of "range" and "distinct population segment." Credit: Sean Hoban


How important can five words be?  Very!

The 1973 Endangered Species Act states that a species may be regarded as endangered if “threatened with extinction […] throughout all or a significant portion of its range” (my underline, hereafter, SPR).  Remarkably, neither the US Fish and Wildlife Service (FWS) nor National Marine Fisheries Service (NMFS) has had an official policy on the meaning of this phrase for the thirty-nine year history of the Act.  Enter proposal FWS–R9–ES–2011–003 (summarized here), which spells out the Services’ soon-to-be official interpretation of the seemingly innocuous phrase, specifically defining the words “significant” and “range.”

As a conservation biologist working for effective species survival, I would like to share my impressions of the proposal, and encourage all to participate in the public comment, extended until March 7.  How these five words are interpreted will have lasting consequences for species’ listing and subsequent recovery plans and management actions.

After an insightful review of past legislative battles over SPR, the proposal gets down to business on page 5, stating that a definition of “significant” should include (a) the variable to measure and (b) a threshold for that variable.  Further, a) and b) should be based on biological and conservation criteria. We would probably all agree here!  But read on, controversy awaits.

As explained on page 8, in the preamble to the proposal, a portion of a species’ range may be “significant” with respect to a species’ resiliency (ability to recover), redundancy (multiple, distributed “backups”), and/or representation (range of variation).  Also important are “abundance, spatial distribution, productivity, and diversity of the species.” However, these key variables are lacking in the actual proposed interpretation (page 16/17); the actual definition of a SPR is very succinct: “without that portion, the species would be in danger of extinction. If so, the portion is significant.

It is therefore arguable whether the new phrasing improves specificity; this wording seems as open to interpretation and debate as ever.  Further, as noted in several ongoing dialogues on Ecolog-l, and summarized in an open letter by the Center for Biological Diversity, this could “result in species that are severely endangered in portions of their range being denied protection because they are secure in some portion of their range even if that portion is just a fraction.”  Specific examples are argued in recent news articles and blogs.  These commentaries question whether (in the proposal’s words) “the draft policy would result in the Services listing and protecting throughout their ranges species that previously we either would not have listed, or would have listed in only portions of their ranges,” although it might “allow protection and recovery of declining organisms in a more timely and less costly manner,” a key consideration for species truly on the brink.

A possible improvement would be to use phrasing from earlier in the document: “without that portion, the representation, redundancy, or resiliency of the species—or the four viability characteristics used more commonly by NMFS—would be so impaired that the species would have an increased vulnerability to threats to the point that the overall species would be in danger of extinction.”  Another possibility could be to note specific examples of pressing dangers such as loss of genetic biodiversity or decreased reproductive output.

Now, what about “range?”  Another tidy definition: “the general geographical area within which the species is currently found… lost historical range cannot be a significant portion of the range.”  Further, an SPR must be occupied currently; ergo if an area is not occupied, it cannot be an SPR.  The authors explain that only the current range matters because the Act focuses on present and future threats of a species, not its past.  In other words, we don’t look back, we look forward.  Further, current range is a simple, clear, easily measurable criteria.  However, the phrase could be interpreted such that if a species is deemed viable in its current range, however small, it may not be protected.

The document acknowledges, “loss of historical range may have resulted in a species for which distribution and abundance is restricted, gene flow is inhibited, or population redundancy is reduced to such a level that the entity is now vulnerable.”  We must remember the past.  The loss of vast portions of the bald eagles’ range due to DDT poisoning was the reason for its listing, even while core, Alaskan populations were stable.  The myriad of pests, diseases and parasites afflicting our nation’s forest trees (resulting in near extinctions) are examples in which range or abundance is tremendously eroded, but the remnants are (for now) somewhat safe.

There are of course problems with a species’ historic range as a benchmark for protection.  We know that ranges change over time, sometimes drastically.  Ecological systems are not static– what was will never be quite the same again.  What past time point represents a species natural range?  More generally, what specific, quantified, threshold-based role can range and other factors play?  This kind of question is what the Services specifically request feedback on (for other specific requests, see page 18).

The document (we are almost finished!) also discusses classification of portions of the range that cross state and national boundaries (page 13), as well possible conflict between SPR and distinct population segment (DPS)- “a subspecies, race, form, or a unique or disjunct segment of a species.”  In the later case, on page 13, the document seems to say that if only the DPS was threatened, then only the DPS would be protected, hauntingly echoing the President Bush era proposal that only portions of the species range could be protected.  While the majority of the text suggests that if a SPR is identified, then the whole species is protected, as argued here, the almost-footnote DPS discussion suggests that indeed the whole species indeed may not be protected, if a DPS can be identified.  This unfortunately creates the tension and ambiguity that the proposal seeks to solve.

The document might benefit from discussion of specific case studies; only two hypothetical extreme examples are given.  For example, what is the fate of range edge or small populations (which may provide insurance as diseases sweep through the range center), are they DPS, or SPR?

The slowness with which species are currently listed, and endless court battles, attests to the fact that the issue of significance must indeed be addressed to achieve efficiency and efficacy in application of the Endangered Species Act.  The 20-page proposal is a very good start in many ways, but needs improvement, from you readers!  Comments of any length are welcome.

(Thank you to Patrick Hoban and Daniel Borkowski for help writing this post).


Author: Nadine Lymn

ESA Director of Public Affairs

Share This Post On

1 Comment


Submit a Comment

Your email address will not be published. Required fields are marked *