Sampling freshwater turtle populations using hoop nets: Testing potential biases

Mali, Ivana; Brown, Donald J.; Ferrato, Jacqueline R.; Forstner, Michael R. J.

doi:10.1002/wsb.427

Cited by 22 publications

(25 citation statements)

References 20 publications

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“…We captured more males in the spring than later summer, and more males in smaller hoop nets. This was not unexpected as differential capture rates by trap type and season are well documented [47,49,50,[65][66][67][68]. We acknowledge that seasonal and trap differences in sex-specific capture rates could be obscuring any impacts of urbanization on sex-ratio, but we do not think these differences were large enough to do so, given our extreme male skew.…”

Section: Discussionmentioning

confidence: 71%

Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta)

Vanek

Glowacki

2019

Diversity

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Turtles are particularly susceptible to the negative impacts of urbanization due to low mobility and a life history strategy emphasizing long generation times and high adult survival. In addition to declines directly through habitat loss, urbanization has been hypothesized to limit populations of aquatic turtles through changes in population structure, as adult females are disproportionally killed on and near roads, leading to male-biased populations, which can lead to population declines or local extirpations. The purpose of this study was to better understand how urbanization impacts the sex ratios of painted turtles (Chrysemys picta) in an urban ecosystem, as empirical results linking male-biased turtle populations to roads and urbanization are mixed. Using eight years of trapping data from a long-term monitoring program in a suburb of Chicago, IL, USA, we report one of the most male-biased populations (x = 75% male) of turtles in the USA, consistent with prevailing road mortality hypotheses. However, we found no evidence that male-biased populations were related to road density or the amount of protected area around a sampling location and found that impervious surface (a metric of urbanization) was weakly related to less male-biased populations. Our results highlight the importance of replicating ecological studies across space and time and the difficulty in assessing population structure in aquatic turtles. We suggest that active conservation measures may be warranted for the continued persistence of urban turtle populations.Diversity 2019, 11, 72 2 of 13 and degradation [10,13], road mortality [11,[14][15][16], and increased depredation rates by subsidized predators [17][18][19][20]. Understanding how turtles respond to urbanization is imperative in a world with a rapidly increasing urban footprint [4,21] and rapidly shrinking turtle populations [22,23].Urbanization has been hypothesized to further limit populations of aquatic turtles through changes in population structure, as adult females (relative to males and juveniles) are disproportionally killed on and near roads [24][25][26][27][28], and Gibbs and Steen [27] show that turtle populations in the US have become more male-biased over time, coinciding with the proliferation of roads. This problem is particularly insidious as turtle populations can become functionally extinct well before the last turtle in a population actually dies [22,29]. However, empirical results of urbanization impacting the sex ratios of turtle populations are mixed and limited to two species with a limited geographic scope [25,[30][31][32], and a series of recent papers has failed to find an association between roads and male-biased populations [33][34][35][36]. Notably, Bowne et al. [36] found the opposite relationship, and hypothesized that that urbanization could be resulting in warmer nesting locations, leading to more females being produced via environmental sex determination [37] (but see Lambert and Steen [38]).In this study, we attempt to better understand how urbanizat...

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Section: Discussionmentioning

confidence: 71%

Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta)

Vanek

Glowacki

2019

Diversity

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“…Turtle populations were sampled using the most widely used method for monitoring and assessing freshwater turtle populations: baited hoop nets (Mali et al 2014). Baited hoop nets have well-known biases (e.g.…”

Section: Methodsmentioning

confidence: 99%

Population status of freshwater turtles across a PCB contamination gradient

Gibbs¹,

Rouhani²,

Shams³

2017

Aquat. Biol.

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Remarkably few studies on the effects of PCBs on wild turtles have been conducted. We contrasted population-level parameters of 2 species of freshwater turtles, the snapping turtle Chelydra serpentina and the painted turtle Chrysemys picta, across a strong PCB concentration gradient in the upper Hudson River, New York State, USA. Our study employed standardized capture methods that yielded 465 turtles during 1968 trap-nights over 2 yr (2006 and 2007) at 246 trapping sites. Individuals of both turtle species were relatively heavier in a contaminated river segment, but PCB concentration did not otherwise influence relative abundance of turtles, probabilities of habitat occupancy or detection, sex or age ratios, body size, incidence of deformities, external parasite occurrence, or several movement parameters in a manner consistent with adverse impacts to wild turtles. This lack of spatial trend in parameters of wild populations of aquatic turtles across a strong gradient of PCB contamination contrasts with predictions of adverse impacts derived from population modeling, dose-response studies, and tissue residue analyses.

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“…Perangkap jaring-jaring yang digunakan untuk menangkap tuntong laut (Gambar 1) adalah mempunyai ukuran lubang mulut dengan ukuran 6,5 -12 cm (Mali, et al 2014). Banyak jenis dan desain perangkap untuk kura-kura.…”

Section: Pendahuluanunclassified

“…Gambar 1. Perangkap jaring yang digunakan untuk menangkap kura-kura air tawar (Mali, et al 2014 (Polidoro, et al, 2010). Sedangkan organisme yang ada di dalam suatu ekosistem dapat dibagi berdasarkan tingkatan makanan, aliran energi dan hubungan proses interaksi antar individu (Joshi & Ghose, 2014 (Turkelboom, et al 2015), sehingga dapat memberikan manfaat bagi pemangku kepentingan walaupun manfaat yang diterima tidak sesuai dengan yang diinginkan (Felipe-lucia, et al, 2015).…”

Section: Pendahuluanunclassified

Peran Ekosistem Mangrove Sebagai Habitat Populasi Tuntong Laut (Batagur borneoensis, Schlegel & Muller, 1844)

Saputra¹

2019

Preprint

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Terdegradasinya ekosistem mangrove dapat menyebabkan hilangnya biodiversitas mangrove dan keseimbangan layanan ekosistem mangrove. Terganggunya fungsi layanan ekosistem berdampak pada peran mangrove dan mengakibatkan hilangnya suatu spesies. Pengaruh faktor biotik dan abiotik dapat terjadi perubahan yang dapat memberikan kontribusi berbeda terhadap peranan ekosistem mangrove sebagai habitat alaminya. Interaksi antar jenis spesies akan berdampak pada menurunnya jumlah populasi suatu spesies terutama tuntong laut, jika habitatnya terganggu. Tuntong laut mempunyai tingkat sensitifitas yang tinggi terhadap lingkungan yang tercemar, serangan predator maupun aktivitas manusia. Jasa layanan ekosistem mangrove mampu meningkatkan peran dan fungsinya terhadap masuknya zat pencemar dari bahan organik. Selain dijadikan sebagai tempat mencari makan dan tempat berlindung dari serangan predator, fungsi lain mangrove bagi tuntong laut adalah sebagai pengatur mortalitas dalam penyesuaian air yang bersalinitas tinggi. Sehingga tuntong laut mampu bertahan di sungai dan muara yang salinitasnya rendah. Oleh karena itu, kerusakan mangrove dapat mempengaruhi perubahan struktur, komposisi dan fungsi bagi tuntong laut. Peranan masyarakat dalam menjaga ekosistem mangrove sangat menentukan pola pemanfaatan lahan. Aktivitas pemanfaatan lahan perlu mempertimbangkan upaya pengelolaan secara kolektif. Upaya yang dilakukan berupa tindakan restorasi, rehabilitasi dan reklamasi. Peningkatan terhadap layanan ekosistem dievaluasi dengan penilaian terhadap indikator-indikator yang terlibat, metode kuantifikasi dan strategi pengelolaan. Sehingga dari hasil penilaian tersebut dapat memberikan sutu kebijakan dan pemahaman kepada masyarakat terhadap pengelolaan sumber daya mangrove.

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Sampling freshwater turtle populations using hoop nets: Testing potential biases

Cited by 22 publications

References 20 publications

Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta)

Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta)

Population status of freshwater turtles across a PCB contamination gradient

Peran Ekosistem Mangrove Sebagai Habitat Populasi Tuntong Laut (Batagur borneoensis, Schlegel & Muller, 1844)

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Sampling freshwater turtle populations using hoop nets: Testing potential biases

Cited by 22 publications

References 20 publications

Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta)

Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta)

Population status of freshwater turtles across a PCB contamination gradient

Peran Ekosistem Mangrove Sebagai Habitat Populasi Tuntong Laut (Batagur borneoensis, Schlegel &amp; Muller, 1844)

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Peran Ekosistem Mangrove Sebagai Habitat Populasi Tuntong Laut (Batagur borneoensis, Schlegel & Muller, 1844)