Where Have All the Turtles Gone, and Why Does It Matter?

Lovich, Jeffrey E.; Ennen, Joshua R.; Agha, Mickey; Gibbons, J. Whitfield

doi:10.1093/biosci/biy095

Cited by 266 publications

(215 citation statements)

References 78 publications

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“…Whereas wild reptile populations continue to decline, disease remains a growing important demographic risk to these species (Gibbons et al, ; Lovich, Ennen, Agha, & Gibbons, ). Numerous diseases in turtles, ranging from upper respiratory tract disease in Gopherus species (Jacobson et al, ) to an unknown disease that caused 50% mortality in the federally protected flattened musk turtle ( Sternotherus depressus ; Dodd, ), make understanding turtle immune systems critically important to protecting imperiled taxa.…”

Section: Discussionmentioning

confidence: 99%

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Rapid thermal immune acclimation in common musk turtles (Sternotherus odoratus)

2019

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As infectious diseases in ectothermic vertebrates increasingly threaten wild populations, understanding how host immune systems are affected by the environment is key to understanding the process of infection. In this study, we investigated how temperature change and simulated bacterial infection (via lipopolysaccharide [LPS] injection) interacted to regulate innate immunity, as measured by bactericidal ability (BA), phagocytosis rate, and heterophil:lymphocyte ratio (HLR) in common musk turtles (Sternotherus odoratus). We found that LPS stimulated an acute immune response, as measured by an increase in BA, phagocytosis rate, and HLR. When exposed to a 5 or 10°C temperature change for 48 hr, turtles rapidly acclimated to the new temperature by adjusting their immune output. This acclimation was compensatory as seen by elevated rates of immune output in colder animals and decreased rates of immune output in warmer animals. These results indicate that while temperature change may be a constraint on some animals, S. odoratus have the ability to rapidly adjust immunity to match environmental thermal demand. This rapid ability to adjust immunity may be related to the broad geographic distribution of musk turtles. Future research should focus on how immune acclimation in ectotherms varies both intraspecifically and interspecifically across regional scales and geographic distributions.

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Section: Discussionmentioning

confidence: 99%

“…Whereas wild reptile populations continue to decline, disease remains a growing important demographic risk to these species (Gibbons et al, 2000;Lovich, Ennen, Agha, & Gibbons, 2018).…”

Section: Discussionmentioning

confidence: 99%

Rapid thermal immune acclimation in common musk turtles (Sternotherus odoratus)

2019

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“…delayed maturation, longevity) driven by their consistent body plan (i.e. large fixed shell) (Lovich et al, 2018). We test several predictions to examine the interactions between evolutionary drivers of nest site selection and human modifications to turtle nesting habitats and then summarize the most important anthropogenic and environmental variables affecting nesting patterns of the yellow-spotted river turtle in the context of conservation actions needed to ensure river turtle persistence in the Brazilian Amazon.…”

Section: Introductionmentioning

confidence: 99%

Nest removal by humans creates an evolutionary trap for Amazonian freshwater turtles

et al. 2019

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Nest‐site selection exerts a fundamental maternal effect on offspring fitness in oviparous species. In many freshwater turtles, females do not care for their eggs after oviposition but rather rely on a nest's micro‐environment to incubate developing embryos although linkages between oviposition choices and overall fitness remain poorly evaluated. We tested predictions derived from multiple hypotheses to examine nesting patterns of the yellow‐spotted river turtle Podocnemis unifilis, a species imperiled by egg harvesting by humans throughout its range, based on data collected from 73 nesting sites along 118 km of river in the eastern Brazilian Amazon. Nesting area size largely explained nest‐site selection by turtles, but only weakly explained turtle egg harvesting by humans. Despite the wide availability of alternative nesting habitats, turtles do not appear to be capable of avoiding hazardous nesting sites associated with increased egg harvesting by humans. Because signals used by female turtles to select nesting areas are apparently not sufficient for avoiding nesting along rivers accessible to humans, direct conservation action will be vital for persistence of these and likely other Amazonian freshwater turtles.

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“…Unsustainable harvesting is recognized as one of the major factors driving global freshwater turtle decline [12-15]. Over 40% of turtle species are endangered as a result of overexploitation [13, 15, 16]. Although turtles are harvested for various purposes (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…The interplay of these different life history traits has been suggested to create more opportunity to harvest turtles sustainably, at least in one tropical freshwater species in Northern Australia [19, 42]. Earlier age at sexual maturity, higher fecundity, and faster growth rates in this tropical freshwater turtle compared to other turtles [42] may allow their populations to be harvested at 20% annual harvest rate [19], suggesting that the widely held assumption of the biological infeasibility of sustainable harvest programs for freshwater turtles based almost entirely on temperate zone species should be reassessed given the challenges of conserving turtles in rapidly developing tropical regions where most turtle diversity occurs [9, 13].…”

Section: Introductionmentioning

confidence: 99%

Population Dynamics and Biological Feasibility of Sustainable Harvesting as a Conservation Strategy for Tropical and Temperate Freshwater Turtles

Rachmansah

Norris

Gibbs

2019

Preprint

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18Background: Conservation strategies are urgently needed for tropical turtles. Studies conducted 19 exclusively in the temperate zone have revealed that the suite of life history traits that 20 characterizes turtles and includes delayed sexual maturity and high adult survivorship makes 21 sustainable harvest programs an unviable strategy for turtle conservation. However, most turtles 22 are tropical in distribution and the tropics have higher, more constant and more extended ambient 23 temperature regimes that, in general, are more favorable for population growth. 24 Methods: To estimate the capacity of freshwater turtle species from temperate and tropical 25 regions to sustain harvest we synthesized life history traits from 165 freshwater turtle species in 26 12 families (Carettochelydae, Chelidae, Chelydridae, Dermatemydidae, Emydidae, 27 Geoemydidae, Kinosternidae, Pelomedusidae, Platysternidae, Podocnemididae, Staurotypidae 28 and Trionychidae). The influence of climate variables and latitude on freshwater turtle life 29 history traits (clutch size, clutch frequency, age at sexual maturity, and annual adult survival) 30were examined using Generalized Additive Models. The biological feasibility of sustainable 31 harvest in temperate and tropical species was evaluated using a sensitivity analysis of population 32 growth rates obtained from stage structured matrix population models. 33Results: Turtles at low latitudes (tropical zones) exhibit smaller clutch sizes, higher clutch 34 frequency, and earlier age at sexual maturity than those at high latitudes (temperate zone). Adult 35 survival increased weakly with latitude and declined significantly with increasing bioclimatic 36 temperature (mean temperature of warmest quarter). A modeling synthesis of these data indicates 37 that the interplay of life history traits does not create higher harvest opportunity in adults of 38 tropical species. Yet we found potential for sustainable exploitation of eggs in tropical species. 39 Conclusions: Sustainable harvest as a conservation strategy for tropical turtles appears to be as 40 biologically problematic as in temperature zones and likely only possible if the focus is on 41 limited harvest of eggs. Further studies are urgently needed to understand how the predicted 42 population surplus in early life stages can be most effectively incorporated into conservation 43 programs for tropical turtles increasingly threatened by unsustainable exploitation, climate 44 change and deforestation.45 46 47Vertebrate animals are important for human welfare and wellbeing 1-3 , particularly as food, 48 medicine, and cultural uses by rural and aboriginal communities 3-6 . Freshwater turtles are a good 49 example -they are frequently targeted for both subsistence and commercial harvest, primarily 50 by local communities that live in the vicinity of river and wetlands 7-9 . High biomass 10,11 , ease of 51 capture, and extended survival with minimal care in captivity make freshwater turtles a focus for 52 harvest 7-9 . 53Unsustainable harve...

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Where Have All the Turtles Gone, and Why Does It Matter?

Cited by 266 publications

References 78 publications

Rapid thermal immune acclimation in common musk turtles (Sternotherus odoratus)

Rapid thermal immune acclimation in common musk turtles (Sternotherus odoratus)

Nest removal by humans creates an evolutionary trap for Amazonian freshwater turtles

Population Dynamics and Biological Feasibility of Sustainable Harvesting as a Conservation Strategy for Tropical and Temperate Freshwater Turtles

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