California Fish and Wildlife Journal最新文献

{"title":"A tale of two valleys: endangered species policy and the fate of the giant gartersnake","authors":"B. Halstead, P. Valcarcel, Richard Kim, A. C. Jordan, Jonathan P. Rose, Shannon M. Skalos, Gabriel A. Reyes, Julia S. M. Ersan, M. Casazza, Allison M. Essert, A. M. Fulton","doi":"10.51492/CFWJ.CESASI.16","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.16","url":null,"abstract":"By the mid-20th Century, giant gartersnakes (Thamnophis gigas) had lost more than 90% of their Central Valley marsh habitat and were extirpated from more than two-thirds of their range. This massive habitat loss led to their inclusion in the inaugural list of rare species under the California Endangered Species Act (CESA). Listing under the CESA provided giant gartersnakes legal protection and mechanisms for recovery, and subsequent listing under the U.S. Endangered Species Act (federal ESA) further fortified these protections. But how effective has listing under these endangered species acts (ESAs) been at achieving their goal of giant gartersnake recovery? Herein, we review relevant aspects of giant gartersnake ecology, illustrate how listing has benefited giant gartersnakes and what challenges have been faced in slowing declines and recovering populations, and chart a course toward improved conservation, management, and recovery of giant gartersnakes. Although listing as threatened under both state and federal ESAs has not yet achieved recovery of giant gartersnakes, the increased knowledge gained and mechanisms for protecting giant gartersnake habitat on private and public lands developed over the past 50 years has improved conservation of this endemic California snake.","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48290980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of atypical aquatic breeding habitat by the California tiger salamander","authors":"J. Alvarez, M. A. Shea, Sarah M. Foster, Jeffrey T. Wilcox","doi":"10.51492/CFWJ.CESASI.13","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.13","url":null,"abstract":"","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41601552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Notes on reproduction of black toads from California","authors":"S. Goldberg","doi":"10.51492/CFWJ.CESASI.11","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.11","url":null,"abstract":"","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42301655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predation impedes recovery of Sierra Nevada bighorn sheep","authors":"Daniel J. Gammons, Jeffrey L. Davis, David W. German, K. Denryter, J. Wehausen, T. Stephenson","doi":"10.51492/CFWJ.CESASI.27","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.27","url":null,"abstract":"Translocation of animals into formerly occupied habitat is a key element of the recovery plan for Sierra Nevada bighorn sheep (Ovis canadensis sierrae), which are state (California) and federally listed as endangered. However, implementing Sierra bighorn translocations is a significant conservation challenge because of the small size of the extant population and the limited number of herds available to donate translocation stock. One such herd, the Mt. Langley herd, recently became unusable as a translocation source following a substantial population decline. At the time of listing in 1999, predation by mountain lions (Puma concolor; hereafter lion) was considered a primary threat to Sierra bighorn, and since then lion predation may have continued to limit the ability of source herds to provide translocation stock. We evaluated the relationship between lion predation and ewe survival rates within three source herds of the Southern Recovery Unit, compared lion abundance and ewe survival among years of varying predation levels, provided a range of estimated times for the Mt. Langley herd to recover to its former status as a translocation source, and determined if the rates lions have been removed to mitigate Sierra bighorn predation exceeded sustainable harvest guidelines. We found compelling evidence that lion predation has impeded the recovery of Sierra bighorn by reducing survival rates of adult ewes (and consequently, population growth) and by preying upon individuals that could have otherwise been translocated. Ewe survival was poor during years of extreme predation but even during years of typical predation, survival rates were below a level needed to ensure population growth, indicating that years with little or no lion predation may be necessary for the population to grow and meet recovery goals. Because the intensity of predation was related to lion abundance, monitoring lion populations could provide managers with advance warning of periods of extreme predation. We found that following a period of particularly extreme predation, the Mt. Langley herd decreased in abundance far below the threshold needed to be considered a source of translocation stock, resulting in the loss of approximately 25% of the recovery program’s capacity for translocations. It is unclear how many years it will take for this herd to recover, but management actions to reduce lion predation are likely needed for this herd to grow to a size that can afford to donate individuals to translocation efforts in the near future, even when optimistic growth rates are assumed. We found that lion removal may also be needed to prevent predation from leading to Sierra bighorn population decline. Lion removal rates that have been implemented thus far are well below what would be needed to reduce the abundance the eastern Sierra lion population itself. We recommend continued monitoring of Sierra bighorn and sympatric lions and note that lion removal may be required to facilitate big","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48672832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conservation of threatened San Joaquin antelope squirrels: distribution surveys, habitat suitability, and conservation recommendations","authors":"B. Cypher, Erica C. Kelly, Reagen M O’Leary, Scott E. Phillips, L. Saslaw, Erin N. Tennant, Tory L. Westall","doi":"10.51492/CFWJ.CESASI.21","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.21","url":null,"abstract":"The San Joaquin antelope squirrel (Ammospermophilus nelsoni: SJAS) is listed as Threatened pursuant to the California Endangered Species Act due to profound habitat loss throughout its range in the San Joaquin Desert in California. Habitat loss is still occurring and critical needs for SJAS include identifying occupied sites, quantifying optimal habitat conditions, and conserving habitat. Our objectives were to (1) conduct surveys to identify sites where SJAS were present, (2) assess habitat attributes on all survey sites, (3) generate a GIS-based model of SJAS habitat suitability, (4) use the model to determine the quantity and quality of remaining habitat, and (5) use these results to develop conservation recommendations. SJAS were detected on 160 of the 326 sites we surveyed using automated camera stations. Sites with SJAS typically were in arid upland shrub scrub communities where desert saltbush (Atriplex polycarpa) or jointfir (Ephedra californica) were the dominant shrubs, although shrubs need not be present for SJAS to be present. Sites with SJAS usually had relatively sparse ground cover with >10% bare ground and Arabian grass (Schismus arabicus) was the dominant grass. SJAS were more likely to occur on sites where kangaroo rats (Dipodomys spp.) were present and burrow abundance was greater, but SJAS were less likely to be present on sites with California ground squirrels (Otospermophilus beecheyi). Based on our habitat suitability model, an estimated 5,931 km2 of high or moderately high quality habitat and 4,753 km2 of lower quality habitat remain. To conserve SJAS, we recommend (1) conducting additional SJAS surveys on sites not surveyed but with suitable habitat, (2) conserving unprotected lands with suitable habitat, (3) managing vegetation on occupied sites if necessary, (4) restoring disturbed lands to increase suitability for SJAS, and (5) conducting translocations of SJAS to unoccupied sites with suitable habitat.","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44997492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forty years later: monitoring and status of the endangered Coachella Valley fringe-toed lizard","authors":"C. Barrows, Scott A. Heacox","doi":"10.51492/CFWJ.CESASI.14","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.14","url":null,"abstract":"The Coachella Valley fringe-toed lizard, Uma inornata, was listed as endangered under the California Endangered Species Act in 1980. By that time, the lizard’s habitat was already reduced by 90%, fragmented into isolated habitat islands on private property among hundreds of landowners. Ecosystem processes that are essential for delivering sand and maintaining the lizard’s sand dune habitat were already compromised. As challenging as it was to protect its habitat under these conditions, populations of this lizard still occur across much of the area where it was found forty years ago. Annual monitoring was designed to assess the ongoing viability of these populations by quantifying the effects of potential threats and stressors and focusing adaptive management actions where they are most needed. Here we demonstrate how hypothesis-based monitoring identified specific locations where invasive plant control and sand corridor management were needed to maintain the lizard’s populations. By monitoring lizard densities within the context of environmental variables that either drive or inhibit population growth, this monitoring approach informs if, when, and where management actions are needed.","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43274794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Artificial dens for the conservation of San Joaquin kit foxes","authors":"B. Cypher, J. Murdoch, Alexander D. Brown","doi":"10.51492/CFWJ.CESASI.25","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.25","url":null,"abstract":"San Joaquin kit foxes (Vulpes macrotis mutica) are federally endangered and California threatened, primarily due to profound habitat loss. Kit foxes are obligate den users and in some locations den availability may be limited due to natural or anthropogenic factors. We conducted a study during 2001–2004 to determine whether kit foxes would use artificial dens, and if so, whether they exhibited a preference for den designs or construction materials. We tested six different den designs, four different construction materials, and two different chamber types. We constructed 34 dens in 12 locations in Bakersfield, CA. We conducted 9,271 den checks and detected kit foxes or their sign on 1,198 of those checks. Kit foxes may not have found one of the locations, but kit foxes used (i.e., entered) 29 of the 31 dens at the other 11 locations. Kit foxes did not exhibit preferential use of any designs, materials, or chamber types. Internal conditions (i.e., temperature and relative humidity) within artificial dens can provide thermoregulatory and moisture conservation benefits to foxes, although these benefits were not as strong as those provided by natural dens. At least nine other species were documented using the artificial dens, including some that might compete with kit foxes. San Joaquin kit foxes readily used artificial dens and clearly such dens can be used to mitigate den losses or to enhance habitat for kit foxes. Due to lower cost and ease of installation, we recommend installing two-entrance dens constructed of high-density polyethylene plastic with an irrigation valve box for a subterranean chamber.","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45230469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ecological variation among island foxes relative to reproductive events","authors":"Robyn M. Powers, B. Cypher, K. Ralls, J. Randall, Erica C. Kelly","doi":"10.51492/CFWJ.CESASI.24","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.24","url":null,"abstract":"Ecological attributes of a species can vary as resource requirements and social interactions change in response to the annual reproductive cycle. We examined variation in home range size, home range overlap, activity (2005–2006), and food item selection (2006–2007) of island foxes (Urocyon littoralis) on San Nicolas Island relative to reproduction-related events. Home ranges, particularly for males, were larger during the mating period compared with the post-mating, pup-rearing, and non-reproduction periods. Home range overlap with non-mate neighbors also increased during the mating period. The greater home range size and overlap during the mating season is consistent with foxes, particularly males, traveling into the ranges of neighboring pairs in an attempt to secure extra-pair copulations. Daily activity patterns did not vary among the reproductive periods. Use of vertebrate prey items increased during the period when adults would have been provisioning weaning young. These items (e.g., mice, birds, lizards) are protein-rich and easier to transport compared with smaller items (e.g., fruits, snails, insects) that also are commonly consumed by island foxes. Variation in ecological attributes among island foxes across the different seasons defined by reproductive events likely represents efforts to maximize mating opportunities, particularly among adult males, and to secure optimal resources for provisioning growing young. These patterns are consistent with those observed among other small canid species.","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48109322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Current status of the Mohave ground squirrel: an update covering the period 2013–2020","authors":"P. Leitner","doi":"10.51492/CFWJ.CESASI.18","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.18","url":null,"abstract":"The Mohave ground squirrel (Xerospermophilus mohavensis) is endemic to the western Mojave Desert of California. It is restricted to a small geographic area and is listed as Threatened under the California Endangered Species Act. Human development has resulted in loss and degradation of its desert habitat and climate change is believed to pose an additional threat. To determine its current conservation status and geographic distribution, I have assembled all available data from field studies during the years 2013-2020. These data confirm that the species is still present in 4 core areas and that it continues to be widespread in the northern and central portions of its historical range. However, the recent data also confirm earlier conclusions that the Mohave ground squirrel is now extirpated from the southernmost portion of its range. Recent surveys raise concerns about its status in other areas as well. A large-scale trail camera survey on the South Range unit of China Lake Naval Air Weapons Station in 2019 failed to detect the Mohave ground squirrel over much of this large installation. Recent trail camera surveys on Fort Irwin strongly suggest that the closely-related round-tailed ground squirrel (Xerospermophilus tereticaudus) has now replaced the Mohave ground squirrel over most of the base. There is additional evidence that the round-tailed ground squirrel is present in disturbed habitats to the west of Barstow and that hybridization with the Mohave ground squirrel is occurring there. It will be important to protect and conserve currently occupied Mohave ground squirrel habitat in view of this new information.","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46029338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population ecology and survivorship of San Joaquin antelope squirrels in grazed and control plots in the San Joaquin Desert of California","authors":"D. Germano, G. Rathbun, L. Saslaw, B. Cypher","doi":"10.51492/CFWJ.CESASI.20","DOIUrl":"https://doi.org/10.51492/CFWJ.CESASI.20","url":null,"abstract":"The San Joaquin antelope squirrel (Ammospermophilus nelsoni) is endemic to the San Joaquin Desert of California. It has been listed as Threatened by the state of California since 1980 due to profound habitat loss, but a paucity of information could limit conservation efforts for this species. We examined data collected each August during 1997–2006 to determine whether A. nelsoni population attributes differed between grazed and ungrazed study plots. We found that sex ratios, mean weights, percentage of reproductive males, number of young, yearly survival, longevity, overall survivorship, and population growth trajectories all were similar between grazed and ungrazed plots. In general, sex ratios were even, males were heavier than females, some males were reproductive in August (although most females were not), and the number of young was inversely related to residual dry matter. We also found that we captured most individuals only once, but we captured a few squirrels for up to for 5 years, and the populations on both grazed and ungrazed plots were growing during the 10-year study. Our study was only the second long-term investigation of this species and the information is needed for further conservation and recovery efforts.","PeriodicalId":29697,"journal":{"name":"California Fish and Wildlife Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47203195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}