Timothy Coonan | National Park Service (original) (raw)
Papers by Timothy Coonan
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.
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....
Monographs of the Western North American Naturalist, 2014
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.
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
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
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
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
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.
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....
Monographs of the Western North American Naturalist, 2014
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.
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
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
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
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