Growth Rate and an Evaluation of Age Estimation for the Endangered Big-Headed Turtle (<i>Platysternon megacephalum</i>) in China

Sung, Yik Hei; Hau, Billy C.H.; Lau, Michael; Crow, Paul; Kendrick, Roger C.; Buhlmann, Kurt A.; Ades, Gary; Karraker, Nancy E.

doi:10.1670/12-166

Cited by 6 publications

(3 citation statements)

References 40 publications

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“…Captive breeding of P. megacephalum has been attempted by various zoos and hobbyists, yet few instances of this species successfully breeding in captivity have occurred (Shelmidine, Murphy & Massarone, 2016; Sung, Hau & Karraker, 2014; Wei et al, 2016), which may be due to our limited knowledge about their natural history (Sung, Hau & Karraker, 2014). Only recently have researchers begun studying this species in the wild including distribution (Pipatsawasdikul, Voris & Thirakhupt, 2010), spatial ecology (Shen, Pike & Du, 2010; Sung, Hau & Karraker, 2015), growth (Sung et al, 2015) and reproduction (Sung, Hau & Karraker, 2014). The information gained from these studies will benefit conservation programs for the species, but much remains unknown.…”

Section: Introductionmentioning

confidence: 99%

Diet of the endangered big-headed turtlePlatysternon megacephalum

Sung

Hau

Karraker

2016

PeerJ

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Populations of the big-headed turtle Platysternon megacephalum are declining at unprecedented rates across most of its distribution in Southeast Asia owing to unsustainable harvest for pet, food, and Chinese medicine markets. Research on Asian freshwater turtles becomes more challenging as populations decline and basic ecological information is needed to inform conservation efforts. We examined fecal samples collected from P. megacephalum in five streams in Hong Kong to quantify the diet, and we compared the germination success of ingested and uningested seeds. Fruits, primarily of Machilus spp., were most frequently consumed, followed by insects, plant matter, crabs and mollusks. The niche breadth of adults was wider than that of juveniles. Diet composition differed between sites, which may be attributable to the history of illegal trapping at some sites, which reduced the proportion of larger and older individuals. Digestion of Machilus spp. fruits by P. megacephalum enhanced germination success of seeds by about 30%. However, most digested seeds are likely defecated in water in this highly aquatic species, which limits the potential benefit to dispersal. The results of our study can be used by conservation-related captive breeding programs to ensure a more optimal diet is provided to captive P. megacephalum.

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Section: Introductionmentioning

confidence: 99%

Diet of the endangered big-headed turtlePlatysternon megacephalum

Sung

Hau

Karraker

2016

PeerJ

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“…After capture, the carapace length of each individual was recorded, and their sex and age-group were determined. Females and males with mean carapace lengths of more than 100 and 130 mm, respectively, were regarded as adults (Sung et al, 2015a). For identification, captured turtles were uniquely marked on their marginal scutes, with care to avoid injury.…”

Section: Materials S and Me Thodsmentioning

confidence: 99%

Home‐site fidelity and homing behavior of the big‐headed turtle Platysternon megacephalum

Xiao

Lin

et al. 2021

Ecology and Evolution

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Site fidelity is the dispersal distance restriction of an animal and its tendency to return to a stationary site (Switzer, 1993). The most well-known and well-documented example of site fidelity is the nest-site fidelity of egg-laying animals, for example, turtles, including both sea (Tucker, 2010) and freshwater turtles (Bona et al., 2012).However, to our knowledge, home-site fidelity, that is, the ability of an animal to remain at its home site without being displaced (Andres & Chambers, 2006), is only exhibited by very few freshwater turtles, and their fidelity is reportedly very low. For example, common musk turtles Sternotherus odoratus exhibit only 15% fidelity (recaptured individuals in original site/total individuals) to their home site (Andres & Chambers, 2006). Homing behavior, that is, the ability of a displaced animal (moved from a familiar site to an unfamiliar one) to return to its home site, is another aspect of home-site fidelity. A few

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“…Individual growth models have been widely used for freshwater turtles [e.g., 14 – 17 ] but often without consideration for which model best reflects the growth trajectory present in data. The commonly used von Bertalanffy equation shows a steady exponential decline in growth rate towards asymptotic size, whereas others like the Gompertz and logistic equations produce sigmoidal growth curves [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Growing as slow as a turtle: Unexpected maturational differences in a small, long-lived species

et al. 2021

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Turtle body size is associated with demographic and other traits like mating success, reproductive output, maturity, and survival. As such, growth analyses are valuable for testing life history theory, demographic modeling, and conservation planning. Two important but unsettled research areas relate to growth after maturity and growth rate variation. If individuals exhibit indeterminate growth after maturity, older adults may have an advantage in fecundity, survival, or both over younger/smaller adults. Similarly, depending on how growth varies, a portion of the population may mature earlier, grow larger, or both. We used 23-years of capture-mark-recapture data to study growth and maturity in the Spotted Turtle (Clemmys guttata), a species suffering severe population declines and for which demographic data are needed for development of effective conservation and management strategies. There was strong support for models incorporating sex as a factor, with the interval growth model reparametrized for capture-mark-recapture data producing later mean maturation estimates than the age-based growth model. We found most individuals (94%) continued growing after maturity, but the instantaneous relative annual plastral growth rate was low. We recommend future studies examine the possible contribution of such slow, continued adult growth to fecundity and survival. Even seemingly negligible amounts of annual adult growth can have demographic consequences affecting the population vital rates for long-lived species.

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Growth Rate and an Evaluation of Age Estimation for the Endangered Big-Headed Turtle (Platysternon megacephalum) in China

Cited by 6 publications

References 40 publications

Diet of the endangered big-headed turtlePlatysternon megacephalum

Diet of the endangered big-headed turtlePlatysternon megacephalum

Home‐site fidelity and homing behavior of the big‐headed turtle Platysternon megacephalum

Growing as slow as a turtle: Unexpected maturational differences in a small, long-lived species

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