E. Cuevas, Vicente Guzmán-Hernández, A. Uribe-Martínez, Ana Raymundo-Sánchez, R. Herrera-Pavón
Abstract A spatially explicit participatory approach was used to collect fishing effort and sea turtle bycatch data from local fishers at 15 ports in the Yucatan Peninsula, Mexico. These data were combined with satellite telemetry data to define potential bycatch hotspots. This is the first participatory and spatially explicit study on sea turtle bycatch rates in the region. Hawksbill turtles (Eretmochelys imbricata) were the most frequently caught bycatch species, followed by loggerheads (Caretta caretta) and green turtles (Chelonia mydas). Gillnets were the most dangerous for sea turtles, with the greatest incidence of dead turtles caught. Three particular bycatch hotspots were identified at the northeast, northwest, and southwest coasts of the peninsula. Identification of bycatch hotspots is recognized worldwide as a key element for protecting these endangered species, particularly in a region such as the Yucatan Peninsula that harbors critical habitats for ≥ 4 sea turtle species, 2 of them categorized as critically endangered (hawksbills and Kemp's ridleys [Lepidochelys kempii]). The spatially explicit participatory approach is versatile, easy to implement, and strategic for generating information under marine spatial planning for endangered species conservation.
{"title":"Identification of Potential Sea Turtle Bycatch Hotspots Using a Spatially Explicit Approach in the Yucatan Peninsula, Mexico","authors":"E. Cuevas, Vicente Guzmán-Hernández, A. Uribe-Martínez, Ana Raymundo-Sánchez, R. Herrera-Pavón","doi":"10.2744/CCB-1263.1","DOIUrl":"https://doi.org/10.2744/CCB-1263.1","url":null,"abstract":"Abstract A spatially explicit participatory approach was used to collect fishing effort and sea turtle bycatch data from local fishers at 15 ports in the Yucatan Peninsula, Mexico. These data were combined with satellite telemetry data to define potential bycatch hotspots. This is the first participatory and spatially explicit study on sea turtle bycatch rates in the region. Hawksbill turtles (Eretmochelys imbricata) were the most frequently caught bycatch species, followed by loggerheads (Caretta caretta) and green turtles (Chelonia mydas). Gillnets were the most dangerous for sea turtles, with the greatest incidence of dead turtles caught. Three particular bycatch hotspots were identified at the northeast, northwest, and southwest coasts of the peninsula. Identification of bycatch hotspots is recognized worldwide as a key element for protecting these endangered species, particularly in a region such as the Yucatan Peninsula that harbors critical habitats for ≥ 4 sea turtle species, 2 of them categorized as critically endangered (hawksbills and Kemp's ridleys [Lepidochelys kempii]). The spatially explicit participatory approach is versatile, easy to implement, and strategic for generating information under marine spatial planning for endangered species conservation.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"78 - 93"},"PeriodicalIF":0.7,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1263.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42849841","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}
J. Hernández-Cortés, E. Núñez-Lara, E. Cuevas, Vicente Guzmán-Hernández
Abstract The hawksbill turtle (Eretmochelys imbricata) is a critically endangered species with a global distribution and is broadly distributed along the Yucatan Peninsula in the Gulf of Mexico. To complete its life cycle, this species uses sandy beaches with particular environmental conditions that facilitate nesting and hatching. This study aimed to identify if beach physical characteristics influence biological reproductive parameters (hatching and emergence success). Nesting activity was monitored along 18 km of beach in the state of Campeche, Mexico, during 2014. Seventy-eight nests were recorded, 12 physical and environmental variables were measured in the nests and contiguous areas, and the hatching and emergence success of each nest was determined. Beach slope and width had no significant relationship to nest site selection. Nest depth and nest distance to highest tide and vegetation, including vegetation type, did influence hatching and emergence success. Herbaceous and bushy plants were positively correlated with reproductive parameters, highlighting the importance of preserving beach vegetation cover. This parameter was a central structural component of hawksbill nesting habitat, possibly because it influenced nest shading, preventing egg overheating and possible embryo death. Preservation and restoration of vegetation structure on hawksbill nesting beaches is clearly vital to enhancing the reproductive success of this species.
{"title":"Natural Beach Vegetation Coverage and Type Influence the Nesting Habitat of Hawksbill Turtles (Eretmochelys imbricata) in Campeche, Mexico","authors":"J. Hernández-Cortés, E. Núñez-Lara, E. Cuevas, Vicente Guzmán-Hernández","doi":"10.2744/CCB-1280.1","DOIUrl":"https://doi.org/10.2744/CCB-1280.1","url":null,"abstract":"Abstract The hawksbill turtle (Eretmochelys imbricata) is a critically endangered species with a global distribution and is broadly distributed along the Yucatan Peninsula in the Gulf of Mexico. To complete its life cycle, this species uses sandy beaches with particular environmental conditions that facilitate nesting and hatching. This study aimed to identify if beach physical characteristics influence biological reproductive parameters (hatching and emergence success). Nesting activity was monitored along 18 km of beach in the state of Campeche, Mexico, during 2014. Seventy-eight nests were recorded, 12 physical and environmental variables were measured in the nests and contiguous areas, and the hatching and emergence success of each nest was determined. Beach slope and width had no significant relationship to nest site selection. Nest depth and nest distance to highest tide and vegetation, including vegetation type, did influence hatching and emergence success. Herbaceous and bushy plants were positively correlated with reproductive parameters, highlighting the importance of preserving beach vegetation cover. This parameter was a central structural component of hawksbill nesting habitat, possibly because it influenced nest shading, preventing egg overheating and possible embryo death. Preservation and restoration of vegetation structure on hawksbill nesting beaches is clearly vital to enhancing the reproductive success of this species.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"103 - 94"},"PeriodicalIF":0.7,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1280.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42621185","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}
C. Caillouet, S. W. Raborn, D. Shaver, N. Putman, B. J. Gallaway, Katherine L. Mansfield
Abstract The Kemp's ridley (Lepidochelys kempii) is the most endangered sea turtle species. During 1966–2017, an annual count of nests (i.e., clutches of eggs laid) has served as an annual index of Kemp's ridley nesting female abundance on the Gulf of Mexico (GoM) index beach in Tamaulipas, Mexico. This index was increasing exponentially at 19% per year in 2009, but it dropped unexpectedly by more than a third in 2010 and through 2017 remained well below levels predicted. We hypothesize that pre-2010 declining carrying capacity for the Kemp's ridley population within the GoM contributed to this nesting setback. We discuss pre-2010 factors that may have caused carrying capacity to decline, including degradation of the GoM ecosystem, the exponentially increasing Kemp's ridley population, and declining per capita availability of neritic (i.e., postpelagic) Kemp's ridley food, including natural prey and scavenged discarded bycatch from shrimp trawling. We encourage evaluations (especially those within a robust modeling framework) of this hypothesis and others put forth to explain the nesting setback to provide information needed to guide restoration of the population's progress toward recovery.
{"title":"Did Declining Carrying Capacity for the Kemp's Ridley Sea Turtle Population Within the Gulf of Mexico Contribute to the Nesting Setback in 2010−2017?","authors":"C. Caillouet, S. W. Raborn, D. Shaver, N. Putman, B. J. Gallaway, Katherine L. Mansfield","doi":"10.2744/CCB-1283.1","DOIUrl":"https://doi.org/10.2744/CCB-1283.1","url":null,"abstract":"Abstract The Kemp's ridley (Lepidochelys kempii) is the most endangered sea turtle species. During 1966–2017, an annual count of nests (i.e., clutches of eggs laid) has served as an annual index of Kemp's ridley nesting female abundance on the Gulf of Mexico (GoM) index beach in Tamaulipas, Mexico. This index was increasing exponentially at 19% per year in 2009, but it dropped unexpectedly by more than a third in 2010 and through 2017 remained well below levels predicted. We hypothesize that pre-2010 declining carrying capacity for the Kemp's ridley population within the GoM contributed to this nesting setback. We discuss pre-2010 factors that may have caused carrying capacity to decline, including degradation of the GoM ecosystem, the exponentially increasing Kemp's ridley population, and declining per capita availability of neritic (i.e., postpelagic) Kemp's ridley food, including natural prey and scavenged discarded bycatch from shrimp trawling. We encourage evaluations (especially those within a robust modeling framework) of this hypothesis and others put forth to explain the nesting setback to provide information needed to guide restoration of the population's progress toward recovery.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"123 - 133"},"PeriodicalIF":0.7,"publicationDate":"2018-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1283.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69181116","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}
Brian J. Tornabene, R. Bramblett, A. Zale, S. A. Leathe
Abstract The nesting ecology of Apalone spinifera in large North American rivers is largely unknown despite the wide distribution of the species in these naturally dynamic ecosystems. We describe the nesting locations, timing, behavior, and habitat of A. spinifera in relation to natural and anthropogenic factors in the Missouri River. Nesting followed annual peak river stage, mostly occurred in the afternoon when air temperatures were 25°–30°C, and did not occur when human activity was nearby. Apalone spinifera nested in June in a year with average discharge (2012), but nested 20 d later in a year with a large flood event (2011). During the average discharge year, 90% of nests were found on islands, but similar proportions of nests were found on island and mainland habitats during the flood year because many islands were inundated. Nests were mostly in mixed-gravel substrates where vegetation cover was sparse or absent. Depredation occurred only after the emergence of hatchlings (∼ 60 d after nesting) and more often on nests on the mainland than on islands. Emergence rates were ∼ 1.5 times higher in the average year than the flood year, and emergence rates were higher in mixed-gravel nests than in pure-sand nests in 2011. In artificial nests, incubation temperatures averaged ∼ 4.3°C higher in mixed-gravel than in sand substrates, and freezing temperatures in winter penetrated to depths greater than the mean egg chamber depth (7.5 cm) for up to 3 wks. Therefore, incubation might be accelerated in mixed-gravel substrates. Accelerated incubation would enhance reproductive success because freezing temperatures preclude hatchlings from overwintering in nests in our study area. Mountain snowmelt-driven hydrology, coupled with the onset of freezing temperatures in autumn, might create a temporal “runoff-freeze squeeze” that limits the successful reproduction of A. spinifera in some years. However, high runoff also scoured vegetation from shorelines where A. spinifera nested in subsequent years. Natural variation in annual discharge might therefore be crucial to conservation of A. spinifera in large rivers.
{"title":"Factors Affecting Nesting Ecology of Apalone spinifera in a Northwestern Great Plains River of the United States","authors":"Brian J. Tornabene, R. Bramblett, A. Zale, S. A. Leathe","doi":"10.2744/CCB-1298.1","DOIUrl":"https://doi.org/10.2744/CCB-1298.1","url":null,"abstract":"Abstract The nesting ecology of Apalone spinifera in large North American rivers is largely unknown despite the wide distribution of the species in these naturally dynamic ecosystems. We describe the nesting locations, timing, behavior, and habitat of A. spinifera in relation to natural and anthropogenic factors in the Missouri River. Nesting followed annual peak river stage, mostly occurred in the afternoon when air temperatures were 25°–30°C, and did not occur when human activity was nearby. Apalone spinifera nested in June in a year with average discharge (2012), but nested 20 d later in a year with a large flood event (2011). During the average discharge year, 90% of nests were found on islands, but similar proportions of nests were found on island and mainland habitats during the flood year because many islands were inundated. Nests were mostly in mixed-gravel substrates where vegetation cover was sparse or absent. Depredation occurred only after the emergence of hatchlings (∼ 60 d after nesting) and more often on nests on the mainland than on islands. Emergence rates were ∼ 1.5 times higher in the average year than the flood year, and emergence rates were higher in mixed-gravel nests than in pure-sand nests in 2011. In artificial nests, incubation temperatures averaged ∼ 4.3°C higher in mixed-gravel than in sand substrates, and freezing temperatures in winter penetrated to depths greater than the mean egg chamber depth (7.5 cm) for up to 3 wks. Therefore, incubation might be accelerated in mixed-gravel substrates. Accelerated incubation would enhance reproductive success because freezing temperatures preclude hatchlings from overwintering in nests in our study area. Mountain snowmelt-driven hydrology, coupled with the onset of freezing temperatures in autumn, might create a temporal “runoff-freeze squeeze” that limits the successful reproduction of A. spinifera in some years. However, high runoff also scoured vegetation from shorelines where A. spinifera nested in subsequent years. Natural variation in annual discharge might therefore be crucial to conservation of A. spinifera in large rivers.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"63 - 77"},"PeriodicalIF":0.7,"publicationDate":"2018-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1298.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43724935","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}
G. Johnston, J. Mitchell, Georgia A. Shemitz, P. Butt, Jennifer M. Adler
Abstract Animals aggregate to reduce predation risk, facilitate mating, and access resources with patchy distributions. During a long-term study of turtle populations in the Santa Fe River (SFR) ecosystem in northern Florida, we observed a large aggregation of turtles at Gilchrist Blue Springs Park (GBSP) in August–October 2013 and again in March–May 2014. On 8 September 2013, we hand-captured 496 turtles of 5 species in GBSP. The Suwannee cooter (Pseudemys concinna suwanniensis) was the most abundant species in the sample, with 477 individuals representing all demographic groups. Density of this species was 530 turtles/ha and biomass was 2242 kg/ha. We hypothesize that hydrological changes in the SFR basin contributed to the temporary turtle aggregations at GBSP. The 113-km SFR originates as a tannin-stained blackwater stream, but receives input of clear water from ≥ 45 artesian springs in its lower 37 km. Heavy rainfall in the upper SFR basin from Tropical Storm Debby in June 2012 resulted in a large influx of tannic water that overwhelmed the capacity of the springs to dilute the river water. This storm in combination with additional episodes of heavy rainfall and declining spring flows led to an unusually long (34-mo) tannic period in the typically clear lower 37 km of the SFR. The resulting loss of most submerged aquatic macrophytes in the river due to insufficient sunlight may have been the stimulus that led the herbivorous P. c. suwanniensis to seek food in one of the few locations that had abundant submerged aquatic vegetation in 2013 and 2014. Turtles previously marked upriver (to 16 km) and downriver (to 4.6 km) from GBSP were in the aggregation, suggesting the individuals gathered at GBSP represented a large portion of the SFR P. c. suwanniensis population.
{"title":"Origin and Structure of a Large Aggregation of Suwannee Cooters (Pseudemys concinna suwanniensis) in a Florida Spring","authors":"G. Johnston, J. Mitchell, Georgia A. Shemitz, P. Butt, Jennifer M. Adler","doi":"10.2744/CCB-1290.1","DOIUrl":"https://doi.org/10.2744/CCB-1290.1","url":null,"abstract":"Abstract Animals aggregate to reduce predation risk, facilitate mating, and access resources with patchy distributions. During a long-term study of turtle populations in the Santa Fe River (SFR) ecosystem in northern Florida, we observed a large aggregation of turtles at Gilchrist Blue Springs Park (GBSP) in August–October 2013 and again in March–May 2014. On 8 September 2013, we hand-captured 496 turtles of 5 species in GBSP. The Suwannee cooter (Pseudemys concinna suwanniensis) was the most abundant species in the sample, with 477 individuals representing all demographic groups. Density of this species was 530 turtles/ha and biomass was 2242 kg/ha. We hypothesize that hydrological changes in the SFR basin contributed to the temporary turtle aggregations at GBSP. The 113-km SFR originates as a tannin-stained blackwater stream, but receives input of clear water from ≥ 45 artesian springs in its lower 37 km. Heavy rainfall in the upper SFR basin from Tropical Storm Debby in June 2012 resulted in a large influx of tannic water that overwhelmed the capacity of the springs to dilute the river water. This storm in combination with additional episodes of heavy rainfall and declining spring flows led to an unusually long (34-mo) tannic period in the typically clear lower 37 km of the SFR. The resulting loss of most submerged aquatic macrophytes in the river due to insufficient sunlight may have been the stimulus that led the herbivorous P. c. suwanniensis to seek food in one of the few locations that had abundant submerged aquatic vegetation in 2013 and 2014. Turtles previously marked upriver (to 16 km) and downriver (to 4.6 km) from GBSP were in the aggregation, suggesting the individuals gathered at GBSP represented a large portion of the SFR P. c. suwanniensis population.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"54 - 62"},"PeriodicalIF":0.7,"publicationDate":"2018-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1290.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47379521","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}
Abstract The use of plastral scute rings to age turtles is a widely practiced technique, but a lack of rigorous field testing of this method has led to critiques of its usefulness and accuracy. We tested the method's effectiveness for aging spotted turtles (Clemmys guttata) by calculating an Age-Increase Ratio and by recording changes in the number of scutes within a year. We found no correlation between the change in the number of scute rings and the number of years between captures, which likely stems from the observer error associated with the difficulty of accurately counting scutes on older turtles; however, we did record a significant correlation between the number of scute rings and body size.
{"title":"An Examination of the Accuracy of Using Plastral Scute Rings to Age Spotted Turtles (Clemmys guttata)","authors":"Hunter J. Howell, R. Seigel","doi":"10.2744/CCB-1282.1","DOIUrl":"https://doi.org/10.2744/CCB-1282.1","url":null,"abstract":"Abstract The use of plastral scute rings to age turtles is a widely practiced technique, but a lack of rigorous field testing of this method has led to critiques of its usefulness and accuracy. We tested the method's effectiveness for aging spotted turtles (Clemmys guttata) by calculating an Age-Increase Ratio and by recording changes in the number of scutes within a year. We found no correlation between the change in the number of scute rings and the number of years between captures, which likely stems from the observer error associated with the difficulty of accurately counting scutes on older turtles; however, we did record a significant correlation between the number of scute rings and body size.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"104 - 108"},"PeriodicalIF":0.7,"publicationDate":"2018-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1282.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69181090","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}
Andrés Cruz-Quintana, Vicente Guzmán-Hernández, M. Rodríguez-Santiago, J. Canales-Delgadillo
Abstract Although the shores of Campeche, Mexico, are critical breeding grounds for the green turtle (Chelonia mydas), so far there is neither clinical nor ecological information about nesting females at this area; such information could help to improve conservation and management of this species. We describe the blood chemical profile based on 13 analytes, and the effect of prevalence of ectoparasites and epibionts of nesting female green turtles. Although we observed low atypical values for amylase and blood ureic nitrogen, and high atypical values for creatinine, phosphorus, and total bilirubin, these results are likely due to feeding habits and nesting-related stress and not to illness or parasitism.
{"title":"Blood Chemical Profiles and Symbiotic Relationships of Green Turtles (Chelonia mydas) Nesting in Campeche, Mexico","authors":"Andrés Cruz-Quintana, Vicente Guzmán-Hernández, M. Rodríguez-Santiago, J. Canales-Delgadillo","doi":"10.2744/CCB-1288.1","DOIUrl":"https://doi.org/10.2744/CCB-1288.1","url":null,"abstract":"Abstract Although the shores of Campeche, Mexico, are critical breeding grounds for the green turtle (Chelonia mydas), so far there is neither clinical nor ecological information about nesting females at this area; such information could help to improve conservation and management of this species. We describe the blood chemical profile based on 13 analytes, and the effect of prevalence of ectoparasites and epibionts of nesting female green turtles. Although we observed low atypical values for amylase and blood ureic nitrogen, and high atypical values for creatinine, phosphorus, and total bilirubin, these results are likely due to feeding habits and nesting-related stress and not to illness or parasitism.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"109 - 115"},"PeriodicalIF":0.7,"publicationDate":"2018-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1288.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45064744","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}
Abstract Worldwide, scientists have headstarted threatened and endangered reptiles to augment depleted populations. Not all efforts have been successful. For the threatened Agassiz's desert tortoise (Gopherus agassizii), one challenge to recovery is poor recruitment of juveniles into adult populations, and this is being addressed through headstart programs. We evaluated 8 cohorts of juvenile desert tortoises from 1 to 8 yrs old in a headstart program at Edwards Air Force Base, California, for health, behavior, and growth. We also examined capacities of the headstart pens. Of 148 juveniles evaluated for health, 99.3% were below a prime condition index; 14.9% were lethargic and unresponsive; 59.5% had protruding spinal columns and associated concave scutes; 29.1% had evidence of ant bites; and 14.2% had moderate to severe injuries to limbs or shell. Lifetime growth rates for juveniles 1–8 yrs of age were approximately two times less than growth rates reported for wild populations. Tortoises in older cohorts had higher growth rates, and models indicated that high density in pens and burrow sharing negatively affected growth rates. Densities of tortoises in pens (205–2042/ha) were 350–3500 times higher than the average density recorded in the wild (< 1/ha) for tortoises of similar sizes. The predominant forage species available to juveniles were alien annual grasses, which are nutritionally inadequate for growth. We conclude that the headstart pens were of inadequate size, likely contained too few shelters, and lacked the necessary biomass of preferred forbs to sustain the existing population. Additional factors to consider for future reptilian headstart pens include vegetative cover, food sources, soil seed banks, and soil composition.
{"title":"Crowding Affects Health, Growth, and Behavior in Headstart Pens for Agassiz's Desert Tortoise","authors":"J. Mack, H. Schneider, K. Berry","doi":"10.2744/CCB-1248.1","DOIUrl":"https://doi.org/10.2744/CCB-1248.1","url":null,"abstract":"Abstract Worldwide, scientists have headstarted threatened and endangered reptiles to augment depleted populations. Not all efforts have been successful. For the threatened Agassiz's desert tortoise (Gopherus agassizii), one challenge to recovery is poor recruitment of juveniles into adult populations, and this is being addressed through headstart programs. We evaluated 8 cohorts of juvenile desert tortoises from 1 to 8 yrs old in a headstart program at Edwards Air Force Base, California, for health, behavior, and growth. We also examined capacities of the headstart pens. Of 148 juveniles evaluated for health, 99.3% were below a prime condition index; 14.9% were lethargic and unresponsive; 59.5% had protruding spinal columns and associated concave scutes; 29.1% had evidence of ant bites; and 14.2% had moderate to severe injuries to limbs or shell. Lifetime growth rates for juveniles 1–8 yrs of age were approximately two times less than growth rates reported for wild populations. Tortoises in older cohorts had higher growth rates, and models indicated that high density in pens and burrow sharing negatively affected growth rates. Densities of tortoises in pens (205–2042/ha) were 350–3500 times higher than the average density recorded in the wild (< 1/ha) for tortoises of similar sizes. The predominant forage species available to juveniles were alien annual grasses, which are nutritionally inadequate for growth. We conclude that the headstart pens were of inadequate size, likely contained too few shelters, and lacked the necessary biomass of preferred forbs to sustain the existing population. Additional factors to consider for future reptilian headstart pens include vegetative cover, food sources, soil seed banks, and soil composition.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"14 - 26"},"PeriodicalIF":0.7,"publicationDate":"2018-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1248.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42547649","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}
C. E. Hart, A. Maldonado-Gasca, C. Ley-Quiñónez, Miguel Flores-Peregrina, Jose de Jesús Romero-Villarruel, Oscar S. Aranda-Mena, L. Plata-Rosas, Marco Tena-Espinoza, Israel Llamas-González, A. Zavala-Norzagaray, B. Godley, F. Abreu-Grobois
Abstract Olive ridleys (Lepidochelys olivacea) are the most numerous sea turtle species worldwide and also locally along the Pacific coast of Mexico. Published data on their distribution and nesting abundance along the coast of Nayarit and northern Jalisco, Mexico are, however, scarce. Here we describe the current extent of conservation activities and the history of efforts to protect sea turtles along this 394-km stretch of coastline. We found that 110 km (of the total of 394 km) are monitored by 18 sea turtle conservation programs, which in 2015 accounted for 43.2% of the total shoreline. Olive ridley sea turtle nesting was encountered on all monitored beaches. Our use of hatchery-protected nests as a measure of nesting levels is undoubtedly an underestimate of overall nesting in the region; however, it nevertheless provides a baseline of current nesting intensity in sites under conservation. Bahía de Banderas presented the highest nesting levels in the study area with 46.4% (3742 ± 904; mean ± SD) of the total protected nests (8073 ± 547) while only representing 14.2% (15.4 ± 3.8 km) of the total area monitored (109.6 ± 4.5 km). The results provided here represent a valuable baseline upon which future research and assessments can be built when analyzing the sea turtle conservation progress in the region.
{"title":"Status of Olive Ridley Sea Turtles (Lepidochelys olivacea) After 29 Years of Nesting Rookery Conservation in Nayarit and Bahía de Banderas, Mexico","authors":"C. E. Hart, A. Maldonado-Gasca, C. Ley-Quiñónez, Miguel Flores-Peregrina, Jose de Jesús Romero-Villarruel, Oscar S. Aranda-Mena, L. Plata-Rosas, Marco Tena-Espinoza, Israel Llamas-González, A. Zavala-Norzagaray, B. Godley, F. Abreu-Grobois","doi":"10.2744/CCB-1255.1","DOIUrl":"https://doi.org/10.2744/CCB-1255.1","url":null,"abstract":"Abstract Olive ridleys (Lepidochelys olivacea) are the most numerous sea turtle species worldwide and also locally along the Pacific coast of Mexico. Published data on their distribution and nesting abundance along the coast of Nayarit and northern Jalisco, Mexico are, however, scarce. Here we describe the current extent of conservation activities and the history of efforts to protect sea turtles along this 394-km stretch of coastline. We found that 110 km (of the total of 394 km) are monitored by 18 sea turtle conservation programs, which in 2015 accounted for 43.2% of the total shoreline. Olive ridley sea turtle nesting was encountered on all monitored beaches. Our use of hatchery-protected nests as a measure of nesting levels is undoubtedly an underestimate of overall nesting in the region; however, it nevertheless provides a baseline of current nesting intensity in sites under conservation. Bahía de Banderas presented the highest nesting levels in the study area with 46.4% (3742 ± 904; mean ± SD) of the total protected nests (8073 ± 547) while only representing 14.2% (15.4 ± 3.8 km) of the total area monitored (109.6 ± 4.5 km). The results provided here represent a valuable baseline upon which future research and assessments can be built when analyzing the sea turtle conservation progress in the region.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"27 - 36"},"PeriodicalIF":0.7,"publicationDate":"2018-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1255.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45506627","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}
M. A. López-Luna, F. G. Cupul-Magaña, A. Escobedo-Galván, Adriana González-Hernández, Eric Centenero-alcalÁ, Judith A. Rangel-Mendoza, M. M. Ramirez-Ramirez, Erasmo Cázares-Hernández
Abstract The genus Kinosternon in Mexico is represented by 12 species of which only 2 inhabit the lowlands of the central Pacific region (Kinosternon chimalhuaca and Kinosternon integrum). Based on 15 standard morphological attributes and coloration patterns of 9 individuals, we describe a new microendemic mud turtle species from the central Pacific versant of Mexico. The suite of morphological traits exhibited by Kinosternon sp. nov. clearly differentiates it from other species within the genus Kinosternon by a combination of proportions of plastron and carapace scutes, body size, and a large yellow rostral shield in males. The new species inhabits small streams and ponds in and near the city of Puerto Vallarta, Jalisco. Unfortunately, natural populations are unknown so far. The habitat is damaged by urban growth, and only one female is known. The available information would suggest that Kinosternon vogti sp. nov., is one of the most threatened freshwater turtle species. An urgent conservation program is necessary as well as explorations in the area to find viable populations of the species.
{"title":"A Distinctive New Species of Mud Turtle from Western México","authors":"M. A. López-Luna, F. G. Cupul-Magaña, A. Escobedo-Galván, Adriana González-Hernández, Eric Centenero-alcalÁ, Judith A. Rangel-Mendoza, M. M. Ramirez-Ramirez, Erasmo Cázares-Hernández","doi":"10.2744/CCB-1292.1","DOIUrl":"https://doi.org/10.2744/CCB-1292.1","url":null,"abstract":"Abstract The genus Kinosternon in Mexico is represented by 12 species of which only 2 inhabit the lowlands of the central Pacific region (Kinosternon chimalhuaca and Kinosternon integrum). Based on 15 standard morphological attributes and coloration patterns of 9 individuals, we describe a new microendemic mud turtle species from the central Pacific versant of Mexico. The suite of morphological traits exhibited by Kinosternon sp. nov. clearly differentiates it from other species within the genus Kinosternon by a combination of proportions of plastron and carapace scutes, body size, and a large yellow rostral shield in males. The new species inhabits small streams and ponds in and near the city of Puerto Vallarta, Jalisco. Unfortunately, natural populations are unknown so far. The habitat is damaged by urban growth, and only one female is known. The available information would suggest that Kinosternon vogti sp. nov., is one of the most threatened freshwater turtle species. An urgent conservation program is necessary as well as explorations in the area to find viable populations of the species.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"13 - 2"},"PeriodicalIF":0.7,"publicationDate":"2018-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1292.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44761912","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}
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