4 years ago




SIGNIFICANT PORTION OF RANGE As explained in detail above, the monarch butterfly, Danaus plexippus plexippus, is threatened range-wide with extinction in the foreseeable future due to loss and curtailment of habitat and range, disease, predation, other factors including climate change and pesticide use, and the lack of existing regulations to safeguard the butterfly. North American populations have declined precipitously and are threatened by all five listing factors. Populations outside of North America are also threatened with extinction due to a variety of factors including small population size, host plant eradication, development, disease, global climate change, stochastic weather events including drought and excessive heat, and sea-level rise. The monarch butterfly thus warrants listing due to range-wide threats. Should the Service conclude, however, that the monarch is not threatened range-wide, then the Service must examine whether the monarch is threatened in a significant portion of its range (SPR). The best available scientific information indicates that the monarch plainly is threatened with extinction in the foreseeable future in a significant portion of its range. On July 1, 2014, the Service issued a Final Policy on Interpretation of the Phrase ‘‘Significant Portion of Its Range’’ in the Endangered Species Act’s Definitions of ‘‘Endangered Species’’ and ‘‘Threatened Species’’ (79 FR 37578). According to the policy, a portion of the range of a species is “significant” if its contribution to the viability of the species is so important that, without the members in that portion, the species would be in danger of extinction, or likely to become so in the foreseeable future, throughout all of its range. As an initial matter, this definition violates the Endangered Species Act and relevant judicial precedent. In a case concerning the flat-tailed horned lizard (Phrynosoma mcallii), the Ninth Circuit Court of Appeals specifically rejected a definition of Significant Portion of Range that requires risk of extinction to the species as a whole, stating: If, however, the effect of extinction throughout ‘a significant portion of its range’ is the threat of extinction everywhere, then the threat of extinction throughout ‘a significant portion of its range’ is equivalent to the threat of extinction throughout all its range. Because the statute already defines ‘endangered species’ as those that are ‘in danger of extinction throughout all ... of [their] range,’ the Secretary's interpretation of ‘a significant portion of its range’ has the effect of rendering the phrase superfluous. Such a redundant reading of a significant statutory phrase is unacceptable. Defenders of Wildlife, et al. v. Norton, 258 F.3d 1136, 1145 (9th Cir. 2001). In essentially defining the significant portion of range language out of existence, the Service’s new policy undercuts a critical component of the Act. Indeed, Congress expressly noted that the “significant portion of its range” provision marked “a significant shift in the definition in existing law which considers a species to be endangered only when it is threatened with worldwide extinction” (H.R.Rep. No. 412, 93rd Cong., 1 Sess. (1973). The monarch is a case in point. As this petition demonstrates, the monarch is at risk of extinction in North America, but also occurs as an introduced species in a number of other parts of the world, including Europe, Australia and a number of island nations. A conclusion by the Service Monarch ESA Petition 108

that the entire North American range of an iconic species like the monarch is not significant would provide the clearest of examples of the fact that the policy is fundamentally at odds with the purposes of the Endangered Species Act to protect species before they are at risk of “worldwide extinction” and to conserve the ecosystems upon which species depend. Even under the overly restrictive revised policy, however, the North American monarch population qualifies as significant, and warrants listing as a threatened species. The policy describes the threshold for “significant” in terms of an increase in the risk of extinction for the species based on the principles of conservation biology using the concepts of redundancy, resiliency, and representation. The North American population of the monarch butterfly meets this standard of significance, because North America is the core of the monarch’s range and its loss would cause imperilment everywhere due to the exacerbated risk of extinction to the species if it were only represented by the peripheral, introduced, and vulnerable non-migratory populations found outside continental North America. The North American monarch population is significant because without it, the redundancy, resiliency, and representation of the species would be so impaired that the monarch would have an increased vulnerability to threats to the point that the overall species would be likely to become endangered in the foreseeable future. The loss of the North American portion of the monarch’s range clearly would increase the vulnerability to extinction of the entire species. Monarch populations outside of North America are relatively small and less genetically diverse and already at risk of extinction from stochastic weather events, climate change, habitat loss from development and intentional host plant eradication, disease, sea-level rise, and other factors as discussed in Appendix A. The monarch population in North America is the heart of the species range and if it were to be lost, the species would be vulnerable to extinction on a global scale. In other words, the hypothetical loss of the North American monarch population would cause the species to become endangered, for several reasons: without the North American population, which harbors the vast majority of all monarchs, the population in the remainder of the monarch’s range would not be large enough to be resilient to environmental catastrophes or random variations in environmental conditions; the spatial structure of the entire species would be disrupted and only isolated tangential populations would remain; potentially important elements of genetic diversity would be lost; the overall redundancy, resiliency and representation of the species would be severely compromised. Redundancy (having multiple populations distributed across the landscape; abundance, spatial distribution) provides a margin of safety for a species to withstand catastrophic events. Resiliency (abundance, spatial distribution, productivity) describes the characteristics of a species that allow it to recover from periodic disturbance. Representation (the range of variation found in a species; spatial distribution, diversity) ensures that a species’ adaptive capabilities are conserved. Redundancy, resiliency, and representation are not independent of each other, and some characteristic of a species or area may contribute to all three. For example, distribution across a wide variety of habitats is an indicator of representation, but it may also indicate a broad geographic distribution contributing to redundancy (decreasing the chance that any one event affects the entire species), and the likelihood that some habitat types are less susceptible to certain threats, contributing to resiliency (the ability of the species to recover from disturbance). Monarch ESA Petition 109

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