Nancy E Karraker

Nancy E Karraker
University of Rhode Island | URI · Department of Natural Resources Science

Ph.D.

About

81
Publications
56,646
Reads
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1,430
Citations
Additional affiliations
July 2009 - December 2011
The University of Hong Kong
Position
  • Professor (Assistant)

Publications

Publications (81)
Article
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The Southeast Asian box turtle (Cuora amboinensis) is numerically the most important turtle exported from Indonesia. Listed as Vulnerable by the IUCN, this turtle is heavily harvested and exported for food and traditional medicine in China and for the pet trade primarily in the United States, Europe, and Japan. Despite its significance in global ma...
Article
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Biotic and abiotic factors drive assortative mixing (preference for or sorting with individuals with similar characteristics) in animal populations on a landscape, with implications for dispersal, population structuring, and other ecological and evolutionary processes. However, patterns and generative mechanisms of assortative mixing are overlooked...
Article
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Wildlife road mortality tends to aggregate spatially at locations commonly referred to as road mortality hotspots. Predictive models can be used to identify locations appropriate for mitigation measures that reduce road mortality. However, the influence of imperfect detection (e.g., false absences) during road mortality surveys can lead to inaccura...
Article
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We respond to a surging interest in science communication training for graduate scientists by advocating for a focus on rhetorically informed approaches to STEM writing and its assessment. We argue that STEM communication initiatives would benefit by shifting from a strategic focus on products to a flexible understanding of writing as a practice wo...
Article
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Fire is a key natural process that has shaped ecosystem distribution and composition for hundreds of millions of years. Prescribed fire has become a common and important technique in habitat management. With its ability to alter physical and vegetative conditions, prescribed fire has the potential to change wildlife habitat characteristics in ways...
Article
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There is an urgent need for scientists to improve their communication skills with the public, especially for those involved in applying science to solve conservation or human health problems. However, little research has assessed the effectiveness of science communication training for applied scientists. We responded to this gap by developing a new...
Article
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Rawa Aopa Watumohai National Park (105.194 ha) in Southeast Sulawesi is one of the important conservation areas in Wallacea. This study aimed to measure the diversity of herpetofauna, relative abundance and community similarity in four different habitats. Survey were conducted in January-April 2018 using Visual Encounter Survey (VES) based on time...
Article
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Rawa Aopa Watumohai National Park (105.194 ha) in Southeast Sulawesi is one of the important conservation areas in Wallacea. This study aimed to measure the diversity of herpetofauna, relative abundance and community similarity in four different habitats. Survey were conducted in January-April 2018 using Visual Encounter Survey (VES) based on time...
Article
• Turtles from Asia are on the brink of extinction with 53% of species considered endangered or critically endangered. Unfortunately, the ecology of many threatened species remains largely unknown. • In this study, the diet of the endangered Beale’s eyed turtle (Sacalia bealei) was investigated using two methods, visual faecal content analysis and...
Article
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Despite a 1944 publication questioning the misconception that Eastern Spadefoots (Scaphiopus holbrookii) and other Scaphiopodidae are ‘secretive' outside of rain-induced migration and breeding aggregations, confirmation bias has perpetuated this fallacy. As a result, S. holbrookii is one of the least studied frogs in the United States. Amassing a l...
Article
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The emerging economy of Indonesia has triggered rapid infrastructure development that threatens ecological communities, including within protected areas. The national parks of Indonesia are renowned for their high levels of biodiversity and endemism, yet the impacts of road development within these parks remains understudied. We conducted road mort...
Article
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Background: Freshwater turtle populations are vulnerable to a range of human activities because of particular life history attributes, and anthropogenic impacts can cause shifts in demographic traits, including survival, density and population structure. Asian freshwater turtles have undergone dramatic population declines in recent decades princip...
Article
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The northeastern United States has experienced dramatic alteration to its landscape since the time of European settlement. This alteration has had major impacts on the distribution and abundance of wildlife populations, but the legacy of this landscape change remains largely unexplored for most species of freshwater turtles. We used microsatellite...
Article
Information on the thermal limits and physiology of ectothermic amphibians is crucial to our understanding of their ecology in the natural environment, particularly with predicted global changes in climate. We documented the thermal limits of larvae of three amphibian species native to Hong Kong, and their introduced, invasive predator, the mosquit...
Article
Turtles are one of the most threatened groups of vertebrates worldwide. In the northeastern United States, a legacy of centuries of dramatic landscape alteration has affected freshwater turtle populations, but the relationships between the current landscape and distributions and abundances of freshwater turtles remain poorly understood. We used a s...
Article
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Background Lowland areas in tropical East and Southeast Asia have a long history of conversion from forestland to agricultural land, with many remaining forests being chronically degraded by wood cutting, livestock grazing, and burning. Wetland-breeding amphibians that have evolved in lowland forests in the region have adjusted to changes in habita...
Data
Amphibian data from Hong Kong Raw data from Hong Kong on body condition of Duttaphrynus melanostictus, larval growth and survival of Microhyla fissipes, and embryonic survival of Polypedates melanostictus.
Data
Amphibian data from Thailand Raw data from Thailand on body condition of Duttaphrynus melanostictus, larval growth and survival of Microhyla heymonsi, and embryonic survival of Polypedates leucomystax.
Article
Graduate programs in the sciences offer minimal support for writing, yet there is an increasing need for scientists to engage with the public and policymakers. To address this need, we describe an innovative, cross-disciplinary, National Science Foundation-funded training program in rhetoric and writing for STEM graduate students and faculty at the...
Chapter
Amphibians are important components of ecosystems worldwide and are already being negatively affected by contemporary rapid changes in climate. Climate strongly affects the distribution, abundance, and ecology of amphibian species. Changes in climate will have impacts on amphibian biodiversity that are not uniform across the globe. We highlight geo...
Article
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The maintenance or creation of early successional habitat is commonly employed by natural resource managers, often for the benefit of native wildlife. In southern New England, USA, forest succession has reduced the amount of early successional habitat on the landscape making the creation of such habitat a management priority in the region. However,...
Article
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Forest loss has been associated with reduced survival in many vertebrates, and previous research on amphibians has mostly focused on effects at early life stages. Paramesotriton hongkongensis is a tropical newt that breeds in streams but spends up to 10 months per year in terrestrial habitats. Populations are threatened by habitat degradation and c...
Article
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Evolutionary change has been demonstrated to occur rapidly in human-modified systems , yet understanding how multiple components of global change interact to affect adaptive evolution remains a critical knowledge gap. Climate change is predicted to impose directional selection on traits to reduce thermal stress, but the strength of directional sele...
Article
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The White-lipped Pit Viper (Trimeresurus albolabris) is broadly distributed through South and Southeast Asia, and very little is known about the natural history of the species. In this study, we report on the ecology, demography, reproductive states, and growth rates of T. albolabris in Hong Kong, China. The sex ratio is even in Trimeresurus albola...
Article
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Ansonia hanitschi is a small, stream-breeding toad endemic to Borneo. Little is known about its ecology or behavior. We documented diurnal activity patterns and habitat use, nocturnal habitat use, and body sizes of A. hanitschi near streams and in forests on Gunung Kinabalu, Sabah, Malaysia, on the island of Borneo. We identified 12 unique diurnal...
Article
We report here for the first time horsehair worms (Nematomorpha) from Hong Kong (China). Most specimens belong to the genus Chordodes, and can be assigned to C. bipilus, C. caledoniensis and to C. cf. moutoni. Two specimens have a cuticular pattern resembling the South American species C. peraccae or C. bouvieri, but for Southeast Asia this pattern...
Article
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Populations of the bigheaded 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 need...
Article
Understanding the scales over which land use affects animal populations is critical for conservation planning, and it can provide information about the mechanisms that underlie correlations between species distributions and land use. We used a citizen science database of anuran surveys to examine the relationship between road density, land use and...
Article
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Translocation of ‘nuisance’ snakes is frequently employed on a large scale in densely populated areas in order to mitigate human-wildlife conflict. However, the methods used are often applied haphazardly and are rarely evaluated, especially in tropical Asia. The objective of this study was to assess the effects of long-distance translocation on the...
Article
The Hong Kong newt (Paramesotriton hongkongensis) is a tropical stream-dwelling salamandrid native to Hong Kong and coastal areas of Guangdong Province, China, inhabiting small rocky hill streams and surrounding forests. It is categorized as "near threatened" on the IUCN Red List because of range-wide habitat degradation and vulnerability to over-e...
Article
Relative to other animal taxa, ecotoxicological studies on amphibians are scarce, even though amphibians are experiencing global declines and pollution has been identified as an important threat. Agricultural lands provide important habitats for many amphibians, but often these lands are contaminated with pesticides. We determined the acute toxicit...
Article
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Most populations of big-headed turtles (Platysternon megacephalum), a species distributed in 6 countries in Southeast Asia, have been heavily depleted because of severe hunting pressure for the food and pet trade. As with many other Southeast Asian turtles, low densities of individuals and few remaining populations have limited our ability to study...
Article
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Understanding growth patterns is critical for determining age and size at sexual maturity and longevity in species that are severely threatened by over-collection and habitat loss, particularly in poorly understood species in tropical East Asia. Using data collected during a 9-year mark–recapture study, we fit the von Bertalanffy and logistic growt...
Article
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The big-headed turtle (Platysternon megacephalum) is heavily harvested to support tremendous demands from food and pet markets, and thus its ecology remains poorly understood. The presence of self-sustaining populations in Hong Kong (22 degrees 09'-22 degrees 37'N, 113 degrees 50'-114 degrees 30'E) provides important opportunities to advance our un...
Article
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Invasive species are one of the most serious threats to amphibian populations. We investigated the effects of two invasive (Pomacea canaliculata and Physella acuta) and one native (Radix sp.) snail species on five species of wetland-breeding frogs in Hong Kong. We quantified embryonic survivorship and determined whether particular attributes of amp...
Article
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Reference intervals for blood biochemical analytes and packed cell volume are useful to veterinarians and conservation programs for monitoring the health of threatened species. Populations of the critically endangered Chinese three-striped box turtle, Cuora trifasciata (Bell, 1825), are heavily depleted in the wild because of overharvesting; and ma...
Article
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The island rule describes a trend toward dwarfism of large animals and gigantism of small animals on islands. Studies of vertebrates, including reptiles, report conflicting results regarding the generality of this evolutionary pattern. We studied the size evolution of insular turtles at the intra- and interspecific levels, as well as the clade leve...
Article
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Over 20 species of amphibians are being harvested in Asia with local consumption exceeding the volume of international export in some countries. Over-harvesting is a particular concern for large-bodied species as their life history traits often make them prone to population depletion. Quasipaa spinosa is a large, stream-dwelling frog that is consid...
Article
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Paramesotriton hongkongensis has a highly restricted distribution in southern China, and a comprehensive study of the species' basic ecology in aquatic and terrestrial habitats has not been previously undertaken. Using mark-recapture methods, we assessed seasonal patterns of breeding populations in four streams in Hong Kong every 3 wk over 18 mo (2...
Article
Abiotic factors have been demonstrated to mediate predator–prey interactions in aquatic and terrestrial communities. For amphibians changes in pH, pollutants, temperature, ultraviolet-B, and moisture levels can alter behavioral, developmental, and physiological aspects of predator–prey relationships resulting in reduced survivorship. Some rhacophor...
Conference Paper
Background/Question/Methods Habitat loss and fragmentation represent significant threats to amphibians. Fragmentation is particularly harmful because many amphibians migrate between aquatic and terrestrial habitats, and even narrow bands of unsuitable habitat can act as barriers to movement. Additionally, amphibians are slow-moving and prone to r...
Article
Full-text available
Harvesting pressure on Asian freshwater turtles is severe, and dramatic population declines of these turtles are being driven by unsustainable collection for food markets, pet trade, and traditional Chinese medicine. Populations of big-headed turtle (Platysternon megacephalum) have declined substantially across its distribution, particularly in Chi...
Article
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Ecotoxicity tests are often conducted following standard methods, and thus carried out at a fixed water temperature under controlled laboratory conditions. Yet, toxicity of a chemical contaminant may vary in a temperature-dependent manner, depending on the physiology of the test organism and physicochemical properties of the chemical. Although an a...
Conference Paper
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Conservation efforts generally focus on species that are rare and restricted in distribution, while those considered common and widespread are often overlooked. However, it is becoming apparent that commonness does not protect a species from extinction in this age of rapid environmental change. Moreover, the phenomenon of cryptic diversity raises t...
Article
Deforestation is one of the major causes of biodiversity loss. Globally, large areas of primary forest have been replaced by secondary forests and plantations, and changes in tree species composition have often led to alteration of plant and animal communities that were associated with those primary forests. Hong Kong has experienced a long history...
Article
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Southeast Asia exhibits high herpetofaunal biodiversity, yet many areas and taxa in the region remain understudied. Extensive surveys are needed to fill information gaps, yet at present we have little knowledge about the effectiveness of different herpetofaunal survey methods in the region. We conducted field studies to examine the effectiveness of...
Article
Predators are important determinants of amphibian community structure in aquatic habitats, and larval odonates can be significant predators of amphibian larvae. Despite their toxicity as adults, the palatability of bufonid eggs and tadpoles to vertebrate and invertebrate predators remains widely debated. I tested the palatability of hatchling tadpo...
Article
It has been postulated that road deicing salts are sufficiently diluted by spring rains to ameliorate any physiological impacts to amphibians breeding in wetlands near roads. We tested this conjecture by exposing clutches of the spotted salamander (Ambystoma maculatum) to three chloride concentrations (1 mg/L, 145 mg/L, 945 mg/L) for nine days, the...
Article
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Despite an increasing understanding of the effects of roadways on amphibian populations, no studies have examined road effects on demographic traits other than survival. We predicted that road mortality could exert a disproportionate effect on fecundity in long-lived species due to shifts in population age structures to younger individuals of small...
Article
Approximately 30% of amphibian species are threatened due to a variety of factors affecting their habitats and physiology, yet contributions that interactions among factors make to population declines are not well-explored. Two factors, introduced mosquitofish (Gambusia affinis) and increased salinity, may coincide in lowland habitats used by breed...
Article
a b s t r a c t Many amphibian species are plastic in their selection of breeding sites and use both short-and longer-hydroperiod wetlands. Understanding which wetland types are most important to amphibian production is critical for focusing conservation efforts. We compared reproduction of wood frogs (Rana sylvatica) and spotted salamanders (Ambys...
Article
Some causative agents of amphibian declines act synergistically to impact individual amphibians and their populations. In particular, pathogenic water molds (aquatic oomycetes) interact with environmental stressors and increase mortality in amphibian embryos. We documented colonization of eggs of three amphibian species, the wood frog (Rana sylvati...
Article
Deicing agents, primarily road salt, are applied to roads in 26 states in the United States and in a number of European countries, yet the scale of impacts of road salt on aquatic organisms remains largely under-studied. The issue is germane to amphibian conservation because both adult and larval amphibians are known to be particularly sensitive to...
Article
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Terrestrial salamanders are integral components of forest ecosystems and the examination of their feeding habits may provide useful information regarding various ecosystem processes. We studied the diet of the Del Norte Salamander (Plethodon elongatus) and assessed diet differences between age classes, genders, and seasons. The stomachs of 309 suba...
Article
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Deicing agents have been used to control ice build-up on roads in winter for at least five decades in North Americaand Europe. This legacy of contamination of streams and wetlands threatens the availability of fresh water in these regions.The issue is of interest because amphibian skin and membranes of amphibian eggs are highly permeable, rendering...
Article
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Tailed frogs (Ascaphus spp.) oviposit in cryptic locations in streams of the Pacific Northwest and Rocky Mountains. This aspect of their life history has restricted our understand-ing of their reproductive ecology. The recent split of A. montanus in the Rocky Mountains from A. truei was based on molecular differentiation, and comparisons of their e...
Article
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Conservation needs for amphibians in managed timberlands may differ based upon the species present and the timber harvesting methods employed. Clearcuts have been documented to be detrimental to amphibians but the impacts of associated silvicultural edges and alternative harvesting treatments are not well understood. The primary objective of this s...