Timothy Coonan - Profile on Academia.edu (original) (raw)
Papers by Timothy Coonan
PLOS ONE, 2015
Island endemics are typically differentiated from their mainland progenitors in behavior, morphol... more Island endemics are typically differentiated from their mainland progenitors in behavior, morphology, and genetics, often resulting from long-term evolutionary change. To examine mechanisms for the origins of island endemism, we present a phylogeographic analysis of whole mitochondrial genomes from the endangered island fox (Urocyon littoralis), endemic to California's Channel Islands, and mainland gray foxes (U. cinereoargenteus). Previous genetic studies suggested that foxes first appeared on the islands >16,000 years ago, before human arrival (~13,000 cal BP), while archaeological and paleontological data supported a colonization >7000 cal BP. Our results are consistent with initial fox colonization of the northern islands probably by rafting or human introduction~9200-7100 years ago, followed quickly by human translocation of foxes from the northern to southern Channel Islands. Mitogenomes indicate that island foxes are monophyletic and most closely related to gray foxes from northern California that likely experienced a Holocene climate-induced range shift. Our data document rapid morphological evolution of island foxes (in~2000 years or less). Despite evidence for bottlenecks, island foxes have generated and maintained multiple mitochondrial haplotypes. This study highlights the intertwined evolutionary history of island foxes and humans, and illustrates a new approach for investigating the evolutionary histories of other island endemics.
On the Fast Track to Recovery: Island Foxes on the Northern Channel Islands
Monographs of the Western North American Naturalist, 2014
ABSTRACT The island fox (Urocyon littoralis) represents an unusual case of a species that achieve... more ABSTRACT The island fox (Urocyon littoralis) represents an unusual case of a species that achieved virtual recovery a mere 15 years after population declines were first discovered. Island fox subspecies on San Miguel, Santa Rosa, and Santa Cruz islands declined precipitously in the mid-1990s due to predation by Golden Eagles (Aquila chrysaetos), which had not historically bred on the islands. In 2008, a 10-year period of recovery action implementation ended. The recovery program had included captive breeding and reintroduction of island foxes and capture and relocation of Golden Eagles. Free-ranging fox populations have been monitored to assess recovery of each subspecies and to detect potential threats of disease and predation. Monitoring included (1) annual grid trapping to allow estimation of annual population size via capture-mark-recapture methods and (2) systematic surveillance of radio-collared foxes to allow estimation of mortality rates and causes. A comprehensive demographic modeling effort produced a population recovery tool that uses adult mortality and population size estimates from the monitoring programs to estimate extinction risks for each fox population. The tool allows managers to assess when threats are sufficiently mitigated to consider populations acceptably safe from extinction. Population monitoring indicates that island foxes on the northern Channel Islands have increased up to 30-fold from population lows and that annual survival has been 90% or better in most years. The San Miguel and Santa Cruz subspecies have approached or reached predecline population levels, and application of the recovery tool indicates they will be biologically recovered by 2013. Biological recovery of the Santa Rosa subspecies, hindered by predation which caused lower survival in 2010, will occur by 2017.
Progress in island fox recovery efforts on the northern Channel Islands
From 1994 to 2002, island fox (Urocyon littoralis) populations on San Miguel, Santa Rosa, and San... more From 1994 to 2002, island fox (Urocyon littoralis) populations on San Miguel, Santa Rosa, and Santa Cruz islands declined to 15, 14, and 75-100 adult foxes, respectively, due to predation by golden eagles (Aquila chrysaetos). In 1999, we initiated capture and translocation of golden eagles and captive breeding of island foxes to prevent likely extinction of the three subspecies. From 1999 to 2003, 29 golden eagles were removed from Santa Cruz Island, and two from Santa Rosa Island, primarily by live-trapping with a bownet, and 5-8 eagles remained on the northern Channel Islands. Predation on island foxes continued throughout the eagle removal period, with golden eagle predation identified as cause of mortality for 22 of 26 radio-collared foxes that died on Santa Cruz Island from 2000 to 2003. In 1999 and 2000, the remaining wild island foxes on San Miguel Island (14) and Santa Rosa Island (14) were brought into captivity, with only one fox remaining in the wild on San Miguel Island....
Evaluation of New Telemetry Technologies for Research on Island Foxes
Monographs of the Western North American Naturalist, 2014
Seroprevalence of Bartonella spp. in the endangered island fox (Urocyon littoralis)
Veterinary Microbiology, 2009
Bartonella clarridgeiae-like strains, presently B. rochalimae, were isolated in gray foxes (Urocy... more Bartonella clarridgeiae-like strains, presently B. rochalimae, were isolated in gray foxes (Urocyon cinereoargenteus) in mainland California. The objective of this study was to investigate the presence of Bartonella infection in the endangered island fox (Urocyon littoralis) found only on the Channel Islands off the Californian coast. Between 2001 and 2004, 263 serum samples were collected. Antibodies against Bartonella vinsonii subsp. berkhoffii (Bvb) and B. clarridgeiae (Bc) were detected using an immuno-fluorescence antibody test. Sixty-eight (25.8%) and 73 (27.7%) foxes were positive for Bvb and Bc, respectively. Seroprevalence was the highest on Santa Cruz Island (n=36, Bvb=80.5%; Bc=86.1%) and Santa Rosa Island (n=38, Bvb=52.6%; Bc=65.8%). On San Miguel and San Clemente Islands, seroprevalence for Bvb was 20% and 17.3% respectively, and 0% and 21.3% for Bc. Prevalence ranged between 0% and 5.1% on San Nicolas and Santa Catalina Islands. Foxes from Santa Rosa and Santa Cruz Islands were 17.5 times and 31.5 times as likely to be seropositive for Bvb and Bc than foxes from the other islands (95% confidence interval [95% CI]=8.5, 36.7; 14.4, 70.2). There were no statistically significant differences for presence of Bartonella antibodies by sex, age, origin (captive vs. wild) or year of blood collection. This is the first report of exposure to Bartonella in the island fox population. Further studies are necessary to isolate these bacteria from foxes and determine factors associated with presence or absence of Bartonella species on specific islands.
PLOS ONE, 2015
Island endemics are typically differentiated from their mainland progenitors in behavior, morphol... more Island endemics are typically differentiated from their mainland progenitors in behavior, morphology, and genetics, often resulting from long-term evolutionary change. To examine mechanisms for the origins of island endemism, we present a phylogeographic analysis of whole mitochondrial genomes from the endangered island fox (Urocyon littoralis), endemic to California's Channel Islands, and mainland gray foxes (U. cinereoargenteus). Previous genetic studies suggested that foxes first appeared on the islands >16,000 years ago, before human arrival (~13,000 cal BP), while archaeological and paleontological data supported a colonization >7000 cal BP. Our results are consistent with initial fox colonization of the northern islands probably by rafting or human introduction~9200-7100 years ago, followed quickly by human translocation of foxes from the northern to southern Channel Islands. Mitogenomes indicate that island foxes are monophyletic and most closely related to gray foxes from northern California that likely experienced a Holocene climate-induced range shift. Our data document rapid morphological evolution of island foxes (in~2000 years or less). Despite evidence for bottlenecks, island foxes have generated and maintained multiple mitochondrial haplotypes. This study highlights the intertwined evolutionary history of island foxes and humans, and illustrates a new approach for investigating the evolutionary histories of other island endemics.
Isolation or detection of Bartonella vinsonii subspecies berkhoffii and Bartonella rochalimae in the endangered island foxes (Urocyon littoralis)
Veterinary Microbiology, 2011
Bartonella rochalimae (B.r.) and Bartonella vinsonii subsp. berkhoffii (B.v.b.) have been isolate... more Bartonella rochalimae (B.r.) and Bartonella vinsonii subsp. berkhoffii (B.v.b.) have been isolated from gray foxes (Urocyon cinereoargenteus) in mainland California and high Bartonella seroprevalence was reported in island foxes (U. litorralis), especially from Santa Cruz and Santa Rosa Islands. As a follow-up study, the objectives were to determine the prevalence of Bartonella bacteremia and seropositivity and to identify the Bartonella species infecting a convenience sample of 51 island foxes living on Santa Rosa Island. Using an immuno-fluorescence antibody test directed against B.v.b and Bartonella clarridgeiae (B.c.), used as a substitute for B.r., the overall antibody prevalence was 62.7% with 16 (31.4%) foxes seropositive for B.c. only, 5 (9.8%) for B.v.b. only, and 11 (21.6%) for both antigens. B.v.b. was isolated from 6 (11.8%) foxes using blood culture medium. An additional seropositive fox tested PCR positive for B.v.b. and 3 other seropositive foxes tested PCR positive for B. rochalimae. All of the isolated B.v.b. colonies and the B.v.b. PCR positive sample belonged to type III, the same type found to infect mainland gray foxes. Therefore, Bartonella infection is widespread within this island fox population with evidence for B.v.b. type III reservoir host-specificity. Presence of B. rochalimae in the Channel Islands has been detected for the first time using PCR.
The Southwestern Naturalist, 2005
... Tres carcasas fueron infestadas con un parásito patogénico, Angiocaulus gubernaculatus, que n... more ... Tres carcasas fueron infestadas con un parásito patogénico, Angiocaulus gubernaculatus, que no se encuentra en las poblaciones de zorros en las islas de San Nicolás, San Clemente, Santa Catalina, Santa Cruz o Santa Rosa, y 2 carcasas tuvieron Uncinaria ... Cheri A. Jones. ...
Proceedings of the National Academy of Sciences, 2011
The Journal of Wildlife Management, 2013
Journal of Wildlife Diseases, 2000
Island foxes (Urocyon littoralis) are endemic to six of the eight California Channel Islands (USA... more Island foxes (Urocyon littoralis) are endemic to six of the eight California Channel Islands (USA). The island fox is classified as a threatened species by the State of California, and recently three of the six subspecies have experienced abrupt population declines. As part of a continuing effort to determine the cause of the declines, we tested island fox serum samples collected in 1988 (n = 176) and 1997-98 (n = 156) over the entire geographic range of the species for seroprevalence of canine heartworm (Dirofilaria immitis) antigen. Using a commercially available enzyme-linked immunosorbent assay (PetChek, Idexx Laboratories, Westbrook, Maine, USA) we detected heartworm antigen in four of the six populations of island foxes. On San Miguel and Santa Rosa Islands, seroprevalence in adult foxes was >85% (n = 62) in 1988 and increased to 100% (n = 24) in 1997-98. On Santa Cruz Island, seroprevalence in adult foxes decreased from 83% (n = 30) to 58% (n = 26), whereas on San Nicolas Island, seroprevalence increased from 25% (n = 32) to 77% (n = 30) during the same period. All of the pups assayed (n = 33) were seronegative. The seroprevalences of heartworm reported herein for the four populations of island foxes are the highest yet reported for a fox species. However, additional demographic data reported elsewhere suggests that heartworm has not been a major factor in the recent declines of island fox populations.
Journal of Wildlife Diseases, 2012
Hematologic and serum biochemical data collected must be interpreted by comparison with normal re... more Hematologic and serum biochemical data collected must be interpreted by comparison with normal reference intervals generated from healthy animals, within a similar population, because many blood parameters are influenced by diet, environment, and stress. Species-specific reference intervals for the endangered island fox (Urocyon littoralis) are not available. We reviewed hematology and serum biochemistry panels from 280 island foxes sampled from 1999-2008 and established normal reference intervals from clinically healthy foxes using a nonparametric approach. Blood parameters were analyzed for differences in age, sex, island of origin, and captivity status. Alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, and creatine kinase activities, as well as calcium and phosphorus concentrations, were significantly higher in juveniles than in adults, but total protein and globulin concentration was lower for juveniles than for adults. Lymphocyte and eosinophil counts, and blood urea nitrogen (BUN) concentration, in foxes from the northern Channel islands of California, USA (Santa Cruz, Santa Rosa, and San Miguel) were higher when compared with foxes from Santa Catalina Island to the south. Higher lymphocyte and eosinophil numbers in the northern island foxes may be associated with increased levels of parasitism on the northern islands. Differences in BUN concentration in both free-ranging and captive foxes may reflect dietary differences among islands. Although aggressive conservation programs have been enacted, island foxes are still susceptible to infectious and neoplastic diseases and, potentially, to toxins. Island fox species-specific reference intervals will enable managers and veterinarians to better care for sick and injured foxes and will contribute to future population health monitoring.
EVIDENCE FOR INDUCED ESTRUS OR OVULATION IN A CANID, THE ISLAND FOX (UROCYON LITTORALIS)
Journal of Mammalogy, 2007
... Asa, CS and C. Valdespino . 2003. A review of small canid reproduction. Pp. 117–123 in Swift ... more ... Asa, CS and C. Valdespino . 2003. A review of small canid reproduction. Pp. 117–123 in Swift foxes (L. Carbyn and M. Sovada, eds.). Canadian Plains Research Center, University of Regina, Regina, Saskatchewan, Canada. Bauman, JE and A. Hardin . 1998. ...
Ecological Monographs, 2009
Biometricians have made great strides in the generation of reliable estimates of demographic rate... more Biometricians have made great strides in the generation of reliable estimates of demographic rates and their uncertainties from imperfect field data, but these estimates are rarely used to produce detailed predictions of the dynamics or future viability of at-risk populations. Conversely, population viability analysis (PVA) modelers have increased the sophistication and complexity of their approaches, but most do not adequately address parameter and model uncertainties in viability assessments or include important ecological drivers. Merging the advances in these two fields could enable more defensible predictions of extinction risk and better evaluations of management options, but only if clear and interpretable PVA results can be distilled from these complex analyses and outputs. Here, we provide guidance on how to successfully conduct such a combined analysis, using the example of the endangered island fox (Urocyon littoralis), endemic to the Channel Islands of California, USA. This more rigorous demographic PVA was built by forming a close marriage between the statistical models used to estimate parameters from raw data and the details of the subsequent PVA simulation models. In particular, the use of mark-recapture analyses and other likelihood and information-theoretic methods allowed us to carefully incorporate parameter and model uncertainty, the effects of ecological drivers, density dependence, and other complexities into our PVA. Island fox populations show effects of density dependence, predation, and El Nin˜o events, as well as substantial unexplained temporal variation in survival rates. Accounting not only for these sources of variability, but also for uncertainty in the models and parameters used to estimate their strengths, proved important in assessing fox viability with different starting population sizes and predation levels. While incorporating ecological drivers into PVA assessments can help to predict realistic dynamics, we also show that unexplained process variance has important effects even in our extremely well-studied system, and therefore must not be ignored in PVAs. Overall, the treatment of causal factors and uncertainties in parameter values and model structures need not result in unwieldy models or highly complex predictions, and we emphasize that future PVAs can and should include these effects when suitable data are available to support their analysis.
Pathogen exposure in endangered island fox (Urocyon littoralis) populations: Implications for conservation management
Biological Conservation, 2006
Island fox (Urocyon littoralis) populations on four California Channel Islands have declined seve... more Island fox (Urocyon littoralis) populations on four California Channel Islands have declined severely since 1994. Canine distemper (CDV) was suspected to be responsible for the decline of the Santa Catalina Island fox, so knowledge of infectious disease exposure in the remaining island fox populations was urgently needed. This study reviewed previous pathogen exposure in island foxes and investigated the current
Genetic diversity of a newly established population of golden eagles on the Channel Islands, California
Biological Conservation, 2012
ABSTRACT Gene flow can have profound effects on the genetic diversity of a founding population de... more ABSTRACT Gene flow can have profound effects on the genetic diversity of a founding population depending on the number and relationship among colonizers and the duration of the colonization event. Here we used data from nuclear microsatellite and mitochondrial DNA control region loci to assess genetic diversity in golden eagles of the recently colonized Channel Islands, California. Genetic diversity in the Channel Island population was low, similar to signatures observed for other recent colonizing island populations. Differences in levels of genetic diversity and structure observed between mainland California and the islands suggests that few individuals were involved in the initial founding event, and may have comprised a family group. The spatial genetic structure observed between Channel Island and mainland California golden eagle populations across marker types, and genetic signature of population decline observed for the Channel Island population, suggest a single or relatively quick colonization event. Polarity in gene flow estimates based on mtDNA confirm an initial colonization of the Channel Islands by mainland golden eagles, but estimates from microsatellite data suggest that golden eagles on the islands were dispersing more recently to the mainland, possibly after reaching the carrying capacity of the island system. These results illustrate the strength of founding events on the genetic diversity of a population, and confirm that changes to genetic diversity can occur within just a few generations.
Animal Conservation, 2001
Introduced species can compete with, prey upon or transmit disease to native forms, resulting in ... more Introduced species can compete with, prey upon or transmit disease to native forms, resulting in devastation of indigenous communities. A more subtle but equally severe effect of exotic species is as a supplemental food source for predators that allows them to increase in abundance and then overexploit native prey species. Here we show that the introduction of feral pigs (Sus scrofa) to the California Channel Islands has sustained an unnaturally large breeding population of golden eagles (Aquila chrysaetos), a native predator. The resulting increase in predation on the island fox (Urocyon littoralis) has caused the near extirpation of three subspecies of this endemic carnivore. Foxes evolved on the islands over the past 20,000 years, pigs were introduced in the 1850s and golden eagles, historically, were only transient visitors. Although these three species have been sympatric for the past 150 years, this predator-prey interaction is a recent phenomenon, occurring within the last decade. We hypothesize that this interaction ultimately stems from human-induced perturbations to the island, mainland and surrounding marine environments.
PLOS ONE, 2015
Island endemics are typically differentiated from their mainland progenitors in behavior, morphol... more Island endemics are typically differentiated from their mainland progenitors in behavior, morphology, and genetics, often resulting from long-term evolutionary change. To examine mechanisms for the origins of island endemism, we present a phylogeographic analysis of whole mitochondrial genomes from the endangered island fox (Urocyon littoralis), endemic to California's Channel Islands, and mainland gray foxes (U. cinereoargenteus). Previous genetic studies suggested that foxes first appeared on the islands >16,000 years ago, before human arrival (~13,000 cal BP), while archaeological and paleontological data supported a colonization >7000 cal BP. Our results are consistent with initial fox colonization of the northern islands probably by rafting or human introduction~9200-7100 years ago, followed quickly by human translocation of foxes from the northern to southern Channel Islands. Mitogenomes indicate that island foxes are monophyletic and most closely related to gray foxes from northern California that likely experienced a Holocene climate-induced range shift. Our data document rapid morphological evolution of island foxes (in~2000 years or less). Despite evidence for bottlenecks, island foxes have generated and maintained multiple mitochondrial haplotypes. This study highlights the intertwined evolutionary history of island foxes and humans, and illustrates a new approach for investigating the evolutionary histories of other island endemics.
On the Fast Track to Recovery: Island Foxes on the Northern Channel Islands
Monographs of the Western North American Naturalist, 2014
ABSTRACT The island fox (Urocyon littoralis) represents an unusual case of a species that achieve... more ABSTRACT The island fox (Urocyon littoralis) represents an unusual case of a species that achieved virtual recovery a mere 15 years after population declines were first discovered. Island fox subspecies on San Miguel, Santa Rosa, and Santa Cruz islands declined precipitously in the mid-1990s due to predation by Golden Eagles (Aquila chrysaetos), which had not historically bred on the islands. In 2008, a 10-year period of recovery action implementation ended. The recovery program had included captive breeding and reintroduction of island foxes and capture and relocation of Golden Eagles. Free-ranging fox populations have been monitored to assess recovery of each subspecies and to detect potential threats of disease and predation. Monitoring included (1) annual grid trapping to allow estimation of annual population size via capture-mark-recapture methods and (2) systematic surveillance of radio-collared foxes to allow estimation of mortality rates and causes. A comprehensive demographic modeling effort produced a population recovery tool that uses adult mortality and population size estimates from the monitoring programs to estimate extinction risks for each fox population. The tool allows managers to assess when threats are sufficiently mitigated to consider populations acceptably safe from extinction. Population monitoring indicates that island foxes on the northern Channel Islands have increased up to 30-fold from population lows and that annual survival has been 90% or better in most years. The San Miguel and Santa Cruz subspecies have approached or reached predecline population levels, and application of the recovery tool indicates they will be biologically recovered by 2013. Biological recovery of the Santa Rosa subspecies, hindered by predation which caused lower survival in 2010, will occur by 2017.
Progress in island fox recovery efforts on the northern Channel Islands
From 1994 to 2002, island fox (Urocyon littoralis) populations on San Miguel, Santa Rosa, and San... more From 1994 to 2002, island fox (Urocyon littoralis) populations on San Miguel, Santa Rosa, and Santa Cruz islands declined to 15, 14, and 75-100 adult foxes, respectively, due to predation by golden eagles (Aquila chrysaetos). In 1999, we initiated capture and translocation of golden eagles and captive breeding of island foxes to prevent likely extinction of the three subspecies. From 1999 to 2003, 29 golden eagles were removed from Santa Cruz Island, and two from Santa Rosa Island, primarily by live-trapping with a bownet, and 5-8 eagles remained on the northern Channel Islands. Predation on island foxes continued throughout the eagle removal period, with golden eagle predation identified as cause of mortality for 22 of 26 radio-collared foxes that died on Santa Cruz Island from 2000 to 2003. In 1999 and 2000, the remaining wild island foxes on San Miguel Island (14) and Santa Rosa Island (14) were brought into captivity, with only one fox remaining in the wild on San Miguel Island....
Evaluation of New Telemetry Technologies for Research on Island Foxes
Monographs of the Western North American Naturalist, 2014
Seroprevalence of Bartonella spp. in the endangered island fox (Urocyon littoralis)
Veterinary Microbiology, 2009
Bartonella clarridgeiae-like strains, presently B. rochalimae, were isolated in gray foxes (Urocy... more Bartonella clarridgeiae-like strains, presently B. rochalimae, were isolated in gray foxes (Urocyon cinereoargenteus) in mainland California. The objective of this study was to investigate the presence of Bartonella infection in the endangered island fox (Urocyon littoralis) found only on the Channel Islands off the Californian coast. Between 2001 and 2004, 263 serum samples were collected. Antibodies against Bartonella vinsonii subsp. berkhoffii (Bvb) and B. clarridgeiae (Bc) were detected using an immuno-fluorescence antibody test. Sixty-eight (25.8%) and 73 (27.7%) foxes were positive for Bvb and Bc, respectively. Seroprevalence was the highest on Santa Cruz Island (n=36, Bvb=80.5%; Bc=86.1%) and Santa Rosa Island (n=38, Bvb=52.6%; Bc=65.8%). On San Miguel and San Clemente Islands, seroprevalence for Bvb was 20% and 17.3% respectively, and 0% and 21.3% for Bc. Prevalence ranged between 0% and 5.1% on San Nicolas and Santa Catalina Islands. Foxes from Santa Rosa and Santa Cruz Islands were 17.5 times and 31.5 times as likely to be seropositive for Bvb and Bc than foxes from the other islands (95% confidence interval [95% CI]=8.5, 36.7; 14.4, 70.2). There were no statistically significant differences for presence of Bartonella antibodies by sex, age, origin (captive vs. wild) or year of blood collection. This is the first report of exposure to Bartonella in the island fox population. Further studies are necessary to isolate these bacteria from foxes and determine factors associated with presence or absence of Bartonella species on specific islands.
PLOS ONE, 2015
Island endemics are typically differentiated from their mainland progenitors in behavior, morphol... more Island endemics are typically differentiated from their mainland progenitors in behavior, morphology, and genetics, often resulting from long-term evolutionary change. To examine mechanisms for the origins of island endemism, we present a phylogeographic analysis of whole mitochondrial genomes from the endangered island fox (Urocyon littoralis), endemic to California's Channel Islands, and mainland gray foxes (U. cinereoargenteus). Previous genetic studies suggested that foxes first appeared on the islands >16,000 years ago, before human arrival (~13,000 cal BP), while archaeological and paleontological data supported a colonization >7000 cal BP. Our results are consistent with initial fox colonization of the northern islands probably by rafting or human introduction~9200-7100 years ago, followed quickly by human translocation of foxes from the northern to southern Channel Islands. Mitogenomes indicate that island foxes are monophyletic and most closely related to gray foxes from northern California that likely experienced a Holocene climate-induced range shift. Our data document rapid morphological evolution of island foxes (in~2000 years or less). Despite evidence for bottlenecks, island foxes have generated and maintained multiple mitochondrial haplotypes. This study highlights the intertwined evolutionary history of island foxes and humans, and illustrates a new approach for investigating the evolutionary histories of other island endemics.
Isolation or detection of Bartonella vinsonii subspecies berkhoffii and Bartonella rochalimae in the endangered island foxes (Urocyon littoralis)
Veterinary Microbiology, 2011
Bartonella rochalimae (B.r.) and Bartonella vinsonii subsp. berkhoffii (B.v.b.) have been isolate... more Bartonella rochalimae (B.r.) and Bartonella vinsonii subsp. berkhoffii (B.v.b.) have been isolated from gray foxes (Urocyon cinereoargenteus) in mainland California and high Bartonella seroprevalence was reported in island foxes (U. litorralis), especially from Santa Cruz and Santa Rosa Islands. As a follow-up study, the objectives were to determine the prevalence of Bartonella bacteremia and seropositivity and to identify the Bartonella species infecting a convenience sample of 51 island foxes living on Santa Rosa Island. Using an immuno-fluorescence antibody test directed against B.v.b and Bartonella clarridgeiae (B.c.), used as a substitute for B.r., the overall antibody prevalence was 62.7% with 16 (31.4%) foxes seropositive for B.c. only, 5 (9.8%) for B.v.b. only, and 11 (21.6%) for both antigens. B.v.b. was isolated from 6 (11.8%) foxes using blood culture medium. An additional seropositive fox tested PCR positive for B.v.b. and 3 other seropositive foxes tested PCR positive for B. rochalimae. All of the isolated B.v.b. colonies and the B.v.b. PCR positive sample belonged to type III, the same type found to infect mainland gray foxes. Therefore, Bartonella infection is widespread within this island fox population with evidence for B.v.b. type III reservoir host-specificity. Presence of B. rochalimae in the Channel Islands has been detected for the first time using PCR.
The Southwestern Naturalist, 2005
... Tres carcasas fueron infestadas con un parásito patogénico, Angiocaulus gubernaculatus, que n... more ... Tres carcasas fueron infestadas con un parásito patogénico, Angiocaulus gubernaculatus, que no se encuentra en las poblaciones de zorros en las islas de San Nicolás, San Clemente, Santa Catalina, Santa Cruz o Santa Rosa, y 2 carcasas tuvieron Uncinaria ... Cheri A. Jones. ...
Proceedings of the National Academy of Sciences, 2011
The Journal of Wildlife Management, 2013
Journal of Wildlife Diseases, 2000
Island foxes (Urocyon littoralis) are endemic to six of the eight California Channel Islands (USA... more Island foxes (Urocyon littoralis) are endemic to six of the eight California Channel Islands (USA). The island fox is classified as a threatened species by the State of California, and recently three of the six subspecies have experienced abrupt population declines. As part of a continuing effort to determine the cause of the declines, we tested island fox serum samples collected in 1988 (n = 176) and 1997-98 (n = 156) over the entire geographic range of the species for seroprevalence of canine heartworm (Dirofilaria immitis) antigen. Using a commercially available enzyme-linked immunosorbent assay (PetChek, Idexx Laboratories, Westbrook, Maine, USA) we detected heartworm antigen in four of the six populations of island foxes. On San Miguel and Santa Rosa Islands, seroprevalence in adult foxes was >85% (n = 62) in 1988 and increased to 100% (n = 24) in 1997-98. On Santa Cruz Island, seroprevalence in adult foxes decreased from 83% (n = 30) to 58% (n = 26), whereas on San Nicolas Island, seroprevalence increased from 25% (n = 32) to 77% (n = 30) during the same period. All of the pups assayed (n = 33) were seronegative. The seroprevalences of heartworm reported herein for the four populations of island foxes are the highest yet reported for a fox species. However, additional demographic data reported elsewhere suggests that heartworm has not been a major factor in the recent declines of island fox populations.
Journal of Wildlife Diseases, 2012
Hematologic and serum biochemical data collected must be interpreted by comparison with normal re... more Hematologic and serum biochemical data collected must be interpreted by comparison with normal reference intervals generated from healthy animals, within a similar population, because many blood parameters are influenced by diet, environment, and stress. Species-specific reference intervals for the endangered island fox (Urocyon littoralis) are not available. We reviewed hematology and serum biochemistry panels from 280 island foxes sampled from 1999-2008 and established normal reference intervals from clinically healthy foxes using a nonparametric approach. Blood parameters were analyzed for differences in age, sex, island of origin, and captivity status. Alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, and creatine kinase activities, as well as calcium and phosphorus concentrations, were significantly higher in juveniles than in adults, but total protein and globulin concentration was lower for juveniles than for adults. Lymphocyte and eosinophil counts, and blood urea nitrogen (BUN) concentration, in foxes from the northern Channel islands of California, USA (Santa Cruz, Santa Rosa, and San Miguel) were higher when compared with foxes from Santa Catalina Island to the south. Higher lymphocyte and eosinophil numbers in the northern island foxes may be associated with increased levels of parasitism on the northern islands. Differences in BUN concentration in both free-ranging and captive foxes may reflect dietary differences among islands. Although aggressive conservation programs have been enacted, island foxes are still susceptible to infectious and neoplastic diseases and, potentially, to toxins. Island fox species-specific reference intervals will enable managers and veterinarians to better care for sick and injured foxes and will contribute to future population health monitoring.
EVIDENCE FOR INDUCED ESTRUS OR OVULATION IN A CANID, THE ISLAND FOX (UROCYON LITTORALIS)
Journal of Mammalogy, 2007
... Asa, CS and C. Valdespino . 2003. A review of small canid reproduction. Pp. 117–123 in Swift ... more ... Asa, CS and C. Valdespino . 2003. A review of small canid reproduction. Pp. 117–123 in Swift foxes (L. Carbyn and M. Sovada, eds.). Canadian Plains Research Center, University of Regina, Regina, Saskatchewan, Canada. Bauman, JE and A. Hardin . 1998. ...
Ecological Monographs, 2009
Biometricians have made great strides in the generation of reliable estimates of demographic rate... more Biometricians have made great strides in the generation of reliable estimates of demographic rates and their uncertainties from imperfect field data, but these estimates are rarely used to produce detailed predictions of the dynamics or future viability of at-risk populations. Conversely, population viability analysis (PVA) modelers have increased the sophistication and complexity of their approaches, but most do not adequately address parameter and model uncertainties in viability assessments or include important ecological drivers. Merging the advances in these two fields could enable more defensible predictions of extinction risk and better evaluations of management options, but only if clear and interpretable PVA results can be distilled from these complex analyses and outputs. Here, we provide guidance on how to successfully conduct such a combined analysis, using the example of the endangered island fox (Urocyon littoralis), endemic to the Channel Islands of California, USA. This more rigorous demographic PVA was built by forming a close marriage between the statistical models used to estimate parameters from raw data and the details of the subsequent PVA simulation models. In particular, the use of mark-recapture analyses and other likelihood and information-theoretic methods allowed us to carefully incorporate parameter and model uncertainty, the effects of ecological drivers, density dependence, and other complexities into our PVA. Island fox populations show effects of density dependence, predation, and El Nin˜o events, as well as substantial unexplained temporal variation in survival rates. Accounting not only for these sources of variability, but also for uncertainty in the models and parameters used to estimate their strengths, proved important in assessing fox viability with different starting population sizes and predation levels. While incorporating ecological drivers into PVA assessments can help to predict realistic dynamics, we also show that unexplained process variance has important effects even in our extremely well-studied system, and therefore must not be ignored in PVAs. Overall, the treatment of causal factors and uncertainties in parameter values and model structures need not result in unwieldy models or highly complex predictions, and we emphasize that future PVAs can and should include these effects when suitable data are available to support their analysis.
Pathogen exposure in endangered island fox (Urocyon littoralis) populations: Implications for conservation management
Biological Conservation, 2006
Island fox (Urocyon littoralis) populations on four California Channel Islands have declined seve... more Island fox (Urocyon littoralis) populations on four California Channel Islands have declined severely since 1994. Canine distemper (CDV) was suspected to be responsible for the decline of the Santa Catalina Island fox, so knowledge of infectious disease exposure in the remaining island fox populations was urgently needed. This study reviewed previous pathogen exposure in island foxes and investigated the current
Genetic diversity of a newly established population of golden eagles on the Channel Islands, California
Biological Conservation, 2012
ABSTRACT Gene flow can have profound effects on the genetic diversity of a founding population de... more ABSTRACT Gene flow can have profound effects on the genetic diversity of a founding population depending on the number and relationship among colonizers and the duration of the colonization event. Here we used data from nuclear microsatellite and mitochondrial DNA control region loci to assess genetic diversity in golden eagles of the recently colonized Channel Islands, California. Genetic diversity in the Channel Island population was low, similar to signatures observed for other recent colonizing island populations. Differences in levels of genetic diversity and structure observed between mainland California and the islands suggests that few individuals were involved in the initial founding event, and may have comprised a family group. The spatial genetic structure observed between Channel Island and mainland California golden eagle populations across marker types, and genetic signature of population decline observed for the Channel Island population, suggest a single or relatively quick colonization event. Polarity in gene flow estimates based on mtDNA confirm an initial colonization of the Channel Islands by mainland golden eagles, but estimates from microsatellite data suggest that golden eagles on the islands were dispersing more recently to the mainland, possibly after reaching the carrying capacity of the island system. These results illustrate the strength of founding events on the genetic diversity of a population, and confirm that changes to genetic diversity can occur within just a few generations.
Animal Conservation, 2001
Introduced species can compete with, prey upon or transmit disease to native forms, resulting in ... more Introduced species can compete with, prey upon or transmit disease to native forms, resulting in devastation of indigenous communities. A more subtle but equally severe effect of exotic species is as a supplemental food source for predators that allows them to increase in abundance and then overexploit native prey species. Here we show that the introduction of feral pigs (Sus scrofa) to the California Channel Islands has sustained an unnaturally large breeding population of golden eagles (Aquila chrysaetos), a native predator. The resulting increase in predation on the island fox (Urocyon littoralis) has caused the near extirpation of three subspecies of this endemic carnivore. Foxes evolved on the islands over the past 20,000 years, pigs were introduced in the 1850s and golden eagles, historically, were only transient visitors. Although these three species have been sympatric for the past 150 years, this predator-prey interaction is a recent phenomenon, occurring within the last decade. We hypothesize that this interaction ultimately stems from human-induced perturbations to the island, mainland and surrounding marine environments.