The watch list comprises taxa that were previously, but are no longer, considered Species of Special Concern. Here we include an explanation for each taxon’s change in status and discuss future conservation concerns regarding Watch List taxa.
Jennings and Hayes (1994a) identified this species as the highest-concern vernal pool-breeding amphibian in the state. In keeping with this assessment and recent research documenting its decline range-wide, A. californiense was listed under the California Endangered Species Act as a Threatened species in 2010, superseding Species of Special Concern status. See Bolster (2010) for the CDFW’s recent status review. The species was also listed under the federal Endangered Species Act in 2000 (Santa Barbara; Endangered), 2003 (Sonoma; Endangered), and 2004 (Central; Threatened), as three separate Distinct Population Segments. Recent multi-locus phylogeographic work indicates that the Central Distinct Population Segment is composed of two separate lineages from the Inner Coast Range and Central Valley and that these may be best considered as separate units with different management needs (J. Johnson and B. Shaffer, unpublished data).
This taxon was included by Jennings and Hayes (1994a) primarily because of habitat loss within its relatively narrow range. We place it on the Watch List because, thus far, it appears to tolerate habitat fragmentation better than many similarly distributed taxa, including the red diamond rattlesnake (Crotalus ruber), coast patch-nosed snake (Salvadora hexalepis virgultea), and California glossy snake (Arizona elegans occidentalis), all of which have experienced more severe declines; and it remains relatively common in many areas throughout its range. It is possible that further development and habitat fragmentation could cause more severe declines, so this taxon should be periodically reevaluated.
Jennings and Hayes (1994a) included the B. rosaliae primarily as a precaution. Virtually nothing was known about the species in California except that, if it ever naturally occurred in the state, it was probably rare and restricted in distribution (only a single specimen has ever been recorded). In the intervening time, no additional specimens have been reported, and no new information has become available for this species. If this species is found to be a native component of the California fauna, the conservation status should be reevaluated when more is known about the populations and habitat of the snake in California.
Jennings and Hayes (1994a) included this taxon primarily over concerns about land use changes within its small range. We shared several of these concerns, although the severity of these threats appears to have decreased since 1994. As long as the planned preservation areas at Tejon Ranch remain in effect, a large amount of E. e. croceater habitat will remain protected, so designation as a Species of Special Concern may not be necessary. We include E. e. croceater on the Watch List to encourage reevaluation of habitat availability for this taxon in the future.
Jennings and Hayes (1994a) included this taxon primarily over concerns about ongoing development within its range. We agree that development has had, and is continuing to have, an impact on this species, although the severity of these impacts appears to be significantly less than those being experienced by other taxa with similar ranges. Further, the large-blotched Ensatina appears to be commonly found with stable populations throughout significant areas of its range, including protected parklands. If the extent of development increases within this salamander’s range, it may become necessary to reconsider special concern status and more active management.
This taxon was included by Jennings and Hayes (1994a) as a precaution, based on its patchy distribution and suspected susceptibility to local extirpations. We do not include H. platycephalus at this time because, although it is patchily distributed, the species appears to be stable throughout most of its range and is not experiencing appreciable risk from habitat disturbance (Wake and Papenfuss 2005). Additional populations have been found since the early 1990s, and the species appears to be relatively common at many sites. Although it is a California endemic, has a moderately small range, and is a narrow ecological specialist, this species does not appear to be currently at risk of immediate decline (Wake and Papenfuss 2005).
The Owens’ Valley populations of H. platycephalus were included by Jennings and Hayes (1994a) as a precaution, both because little was known about the population biology of this elusive salamander and because it was strongly suspected that it was a distinct taxon. Research completed since 1994 suggests that these populations do not form a distinct lineage but instead are part of the more broadly distributed H. platycephalus lineage (Rovito 2010). As with H. platycephalus, additional localities have been found and populations appear to be stable, leading us to conclude that Species of Special Concern designation is not required at the present time (Wake and Papenfuss 2005).
The two southern California subspecies L. z. parvirubra and L. z. pulchra were considered Species of Special Concern by Jennings and Hayes (1994a) on the basis of suspected declines due to illegal collecting and habitat destruction from some collectors. We agree that this has occurred, although the current scale of exploitation does not appear to threaten this species’ long-term survival. We placed the species on the Watch List in recognition that collection pressure and/or habitat destruction could cause the need to provide additional protections in the future.
Jennings and Hayes (1994a) included this taxon primarily because of its small range (it is restricted to Santa Cruz and Santa Rosa islands) and threats from feral ungulates and pigs. We removed this species from special concern status because the invasive mammals causing the primary threats have been removed from the largest part of the range, Santa Cruz Island (USNPS 2010). This island is also well protected from future development because it is a national park.
Jennings and Hayes (1994a) included P. s. interparietalis primarily because it has a relatively restricted range and has disappeared from some areas. As with Aspidoscelis hyperythra, we agree that some declines have occurred, although their severity appears to be modest. If these declines continue, further protections may be warranted in the future.
Jennings and Hayes (1994a) included the Del Norte salamander because of concerns regarding habitat specialization by inland populations and the potential for timber harvest to destroy these habitats. Although these are valid concerns, as well as for two close relatives of P. elongatus, the Scott Bar salamander (Plethodon asupak) and Siskiyou Mountains salamander (P. stormi), population status across most of the range of this taxon appears to be stable. Inland populations are patchy and likely more vulnerable to habitat degradation, which is why we place this taxon on our Watch List (H. Welsh, pers. comm.).
Mountain yellow-legged frogs were designated as Species of Special Concern by Jennings and Hayes (1994a) under the name R. muscosa. Vredenburg et al. (2007) divided R. muscosa (sensu lato) into two species on the basis of morphometric measurements, differences in advertisement call, and mitochondrial DNA: the Sierra Madre yellow-legged frog (R. muscosa) in the south and the Sierra Nevada yellow-legged frog (R. sierrae) in the north. Both species were state listed in 2013, superseding Species of Special Concern status. See Bonham and Lockhart (2011) for the CDFW’s recent status review of these taxa.