occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (5000-20,000 square km (about 2000-8000 square miles)) Known from the Puget Trough/Willamette Valley/Georgia Basin, from west central Oregon, through Washington, to southern Vancouver Island in Canada.
Comments: Dry prairies or prairie-like native grassland in Puget Sount, Willamette portions of range, maritime meadows within Garry oak ecosystems in Canada.
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Comments: Tthe documented foodplants for this subspecies are Castillegia hispida, Plantagot maritima, and the exotic P. lanceolata. Only the last is documented range-wide.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 6 - 20
Comments: Although new, or at least previously undetected, colonies continue to be found as recently as 2006, the number of active known colonies continues to decline. According USFWS (2004) with the discovery of three new locations the total known was 14 colonies, these probably represented seven metapopulation occurrences; one in British Columbia, four in Washington, and two in Oregon. Similarly, a 2005 status report by the Washington Department of Fish and Wildlife listed 13 colonies with ten in four distinct areas of that state. USFWS (2007) reported (as of about 2004-2006) only eleven extant colonies, a tiny one in Canada, eight in Washington, and two in Oregon. Those in Washington cluster into about three or four metapopulation occurrences, and the two in Oregon may be remnants of the same metapopulation but may now be isolated. The original colonies in British Columbia are extirpated but a tiny, previously unknown, colony was discovered on a different island in 2006. Over half of colonies documented as extant in 1997-2002 no longer are. Thus using reasonable definitions of occurrences based on metapopulations there are no more than seven extant, and some of these would not meet any reasonable criteria for viability.
250 - 2500 individuals
Comments: This species, like several others in the genus, is prone to large year to year fluctuations. For example the larger Oregon colony reportedly had over 1200 adults in 2005 and no more than 300 in 2006, which is a relatively modest fluctuation for this species based on better studied subspecies. The remaining Fort Lewis population has increased to over 1000 adults in recent years, but was apparently previously smaller. One of the Fort Lewis populations had about 7000 adults in 1997, but only ten were seen in 2000, and none from 2001 to 2006. According to USFWS (2007) four of the current eleven colonies are believed to usually produce over 100 adults in a generation, and two of these sometimes exceed 1000, one colony seems to produce about 50-100 adults and the other six generally fewer. In very good years the species probably produces more than 2500 adults, but it probably does not approach that number consistently and it is the lower numbers in poor years that most impact viability.
National NatureServe Conservation Status
Rounded National Status Rank: N1 - Critically Imperiled
Rounded National Status Rank: N1 - Critically Imperiled
NatureServe Conservation Status
Rounded Global Status Rank: T1 - Critically Imperiled
Reasons: There were 11 known "populations" which are remnants of fewer, apparently about seven, actual occurrences as of 2006 and it is possible some have died out since and recent extirpation rate for colonies has been over 50% per decade. One population crashed from about 7000 in 1997 to extirpation by 2001. It is not clear whether any remaining populations are viable and somewhat unlikely any colonies not part of functional metapopulations can survive long-term. It is nearly certain there are not more than four viable occurences. This species and others in the genus are subject to large natural fluctuations and local extirpations due to weather, e.g. drought, among other factors. There may also be important unknown threats since some extirpations are unexplained. The subspecies has declined drastically (>99%) in the long term and is still declining and may well be headed toward extinction. This rank also agrees with the S1 ranks throughout its range, listing as endangered in both jurisdictions where that status can be applied to invertebrates, and the determination of critically imperiled by the Xerces Society (see Committee on the Status of Pollinators in North America, 2007). This subspecies has become management-dependent because its habitats are now too small and fragmented, and too heavily invaded by alien weeds, to persist based on natural processes.
Environmental Specificity: Narrow. Specialist or community with key requirements common.
Lead Region: Pacific Region (Region 1)
For most current information and documents related to the conservation status and management of Euphydryas editha taylori, see its USFWS Species Profile
Global Short Term Trend: Decline of 50-70%
Comments: See USFWS (2004 and 2007), over half of known colonies dies out in the last decade, usually for unknown reasons. One population was rediscovered in BC in 2005 or 2006. Of about 30 recent historic sites about 10 were occupied in 2000 and 5 by 2002, suggesting about a 50% loss in two years. However, previously unknown colonies were found. There were also several documented losses in 1990s. As of spring 2004, butterflies were known at 14 locations including three newly discovered as a result of intensive effort. These probably comprised seven or fewer occurrences since some were apparently metapopulations. As of the 2006 season the number had dropped to eleven colonies.
Global Long Term Trend: Decline of >90%
Comments: About 3% of the original grassland habitats remain (USFWS, 2007), but often in degraded condition and most of this is unoccupied, so it is safe to assume more than 97% habitat loss in past 200 years. Also there were at least 70 historic sites actually documented and there were obviously many more than that that were undocumented before being destroyed-especially considering that a few new ones were found as recently as the 2000s. Thus 11 remaining colonies, about seven metapopulations, represents more than a 90% decline in number of populations. Area of occupancy has apparently declined by about 99%, and population size has decline at least comparably.
Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable
Comments: Threats are discussed by both USFWS (2004), The Washington Department of Fish and Wildlife (2005), (Black and Vaughn, 2008), among others. Except for three colonies lost to Btk spraying against gypsy moth and probably one to burning, the decline of this once widespread and common subspecies was almost entirely due to loss of habitat, sometimes by conversion to agriculture or development, but also due to succession caused by lack of fires, and to invasive plants. The current threats include most of the causes of decline, although probably not prescribed burning now, as well as small population sizes (most populations may be under 50 adults most years), and also isolation of many colonies. Where population sizes are small even collecting could be a threat. Small populations at most sites, perhaps all sites in some years, suggest the potential for genetic depletion through inbreeding. Climate change may be or become a threat, especially if the region becomes drier. The inability to explain some or most extirpations suggests there could be other pervasive problems. Some populations of this genus are inherently unstable, occur as metapopulations, and naturally undergo frequent extirpation and recolonization. This includes better known subspecies of this species studied by Ehrlich's lab and also the common eastern E. phaeton. Parasites, drought, depletion of foodplant are among possible factors behind any natural instability, but basically E. editha taylor is now so reduced that effective metapopulation dynamics may be unrestorable. If metapopulations consist of generally only two demes, it is also quite possible both could fail in the same season eliminating the occurrence permanently. All remaining occurrences are at serious risk of extirpation due to almost any natural or unnatural negative impact or to lack of management. Washington Department of Fish and Wildlife, finds that this species is management dependent there, and that state contains over 70% of occurrences. Information from Canada and Oregon suggests similar dependence in those places. The most pervasive overall immediate threats are metapopulation disruption and alteration of remaining habitat scraps by alien weeds (see USFWS 2004) but these are far from the only threats.
Robert M. Pyle mentioned extinction of a well known colony following a prescribed burn in the 1990s in at least two oral presentations attended by D. Schweitzer in the 1990s. Larvae in the litter would not be expected to survive any but the "coolest" prescribed burns unless the fire were quite patchy. It is possible that other populations were lost to prescribed burning. Poorly planned or wild fires at any season are a threat due to direct mortality and must be carefully managed. However, in the larger picture lack of fires has contributed to loss of habitat to succession. BTK spraying aimed at Asian Gypsy Moth probably caused or contributed to loss of three populations in the 1990s (USFWS 2004). Butterflies in general seem to be highly sensitive to BTK despite extreme variability among Lepidoptera in general (Peacock et al. 1998 and other references) which ranges from no impact to almost complete mortality even within the same genus in several families. Euphydryas populations would be fully exposed as mid or late instar larvae and must be assumed highly sensitive unless documented otherwise. This is a widespread threat especially to already small populations.
Euphydryas editha bayensis was remarkably little affected by the now classic deliberate removal (which simulated extreme overcollecting) studies by Ehrlich's workers in the 1970s. There is no plausible mechanism by which a mark-release-recapture study at Ft. Lewis could have caused the the crash of the population from 7000 in 1997 to extirpation by 2001, but it is not known what did, and it is not known in what year the decline actually started. Ehrlich's work strongly implies even outright removal of most adults would probably not have had close to that impact. Most workers are prudently reluctant to conduct such studies with severely stressed populations and it is possible, although not really likely and not actually demonstrated, that such studies when numbers were already very low and declining in the last year or two contributed somewhat to the final demise of the famous Jasper Ridge populations of E. editha bayensis (see McGarrahan 1997). Research activities per se pose little or no threat to E. editha taylori or any viable butterfly population (see also USFWS, 2007), but could add additional threats to already severely declining occurrences. Perhaps more important than handling, which does not cause much mortality, would be persistent disturbance disrupting normal behavior if several persons are present in a small habitat for extended periods (D. schweitzer, personal experience with other species).
Biological Research Needs: Better understanding of causes of those fluctuations and extirpations that cannot be explained by weather or known unnatural disturbances would be useful.
Global Protection: Few to several (1-12) occurrences appropriately protected and managed
Comments: The Canadian occurrence is protected as an endangered species under the Species at Risk Act, and this species is, or recently was, found in Gulf Islands National Park Reserve. Most US populations have varying degrees of protection, for example one in a county park in Oregon. In Washington several major colonies are on public lands, but some of these lands have uses that could be incompatible with butterfly conservation. The USFWS (2007) reports that only about 5% of the species' total occurrence is on private land and over half is at Fort Lewis. The USFWS released a draft recovery plan on September 22 2008 that includes this candidate butterfly as well as several listed taxa from its Oregon habitats, and a similar plan is anticipated for the Willamette prairies in Washington. However, while most sites have some sort of management plan, some have not been implemented.
Euphydryas editha taylori
The Taylor’s Checkerspot, also known as the Whulge Checkerspot, is the darkest subspecies of the Euphydryas genus. This butterfly has a wing span of less than 2.25 inches (57 mm). It gets its name from the checkered color pattern on its wings that consist of black, orange and white coloring. Taylor's Checkerspot once ranged from the Willamette Valley in Oregon to Vancouver Island in British Columbia.
The Taylor’s Checkerspot butterfly is at extreme risk of going extinct. It has been a candidate species for the U.S. Endangered Species Act since 2001. In Washington it is listed as a species of concern and has an active conservation program. In Oregon Taylor’s checkerspot is on the Threatened and Endangered Species list, but receives no protection under state statute. Before its dramatic decline the Taylor’s Checkerspot was documented at more than seventy sites, but is currently found only at twelve sites in Washington and two in Oregon. It is currently listed as endangered in Canada, owing to the recent discovery of populations on Denman Island.
The biggest threat to its survival is the loss of prairie habitat due to contemporary settlement. Since the arrival of European-Americans, more than 99% of the lowland prairies has been destroyed. The reason for this is that prairies are prime locations for agriculture as well as development of all types due to the lack of trees and flat topography. Along with habitat loss the subspecies is impacted by pesticide use that makes their plight even worse. Increased risk of harm due to drought is another major concern since they are now stuck on these patches of habitat with no chance to migrate to more suitable places.
- S. H. Black & D. M. Vaughan (May 2005). "Species profile: Euphydryas editha taylori" (PDF). In M. D. Shepherd, D. M. Vaughan & S. H. Black. Red List of Pollinator Insects of North America. CD-ROM Version 1. Portland, Oregon: Xerces Society.
- Paula Bock (July 15, 2007). "Butterflies aren't free. Saving the planet one bug at a time" (PDF). Seattle Times.
- Cheryl Fimbel (2004). Habitat enhancement for rare butterflies on Fort Lewis prairies (PDF). South Puget Sound Prairie Landscape Working Group.
To request an improvement, please leave a comment on the page. Thank you!