Mitochondrial DNA evolution in the Anaxyrus boreas species group

Goebel, Anna M.; Ranker, Tom A.; Corn, Paul Stephen; Olmstead, Richard G.

doi:10.1016/j.ympev.2008.06.019

Cited by 45 publications

(78 citation statements)

References 99 publications

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“…This provides a unique perspective to the role of climate change in amphibian declines in temperate ecosystems. Previous shifts in climate have had dramatic effects on the distribution, genetics, and ecology of numerous temperate amphibian species (43)(44)(45). The impacts of ongoing climate change will vary across the globe, and this is likely to increase the viability of some species while being detrimental to others.…”

Section: Discussionmentioning

confidence: 99%

Decreased winter severity increases viability of a montane frog population

McCaffery

Maxell

2010

Proc. Natl. Acad. Sci. U.S.A.

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Many proximate causes of global amphibian declines have been well documented, but the role that climate change has played and will play in this crisis remains ambiguous for many species. Breeding phenology and disease outbreaks have been associated with warming temperatures, but, to date, few studies have evaluated effects of climate change on individual vital rates and subsequent population dynamics of amphibians. We evaluated relationships among local climate variables, annual survival and fecundity, and population growth rates from a 9-year demographic study of Columbia spotted frogs (Rana luteiventris) in the Bitterroot Mountains of Montana. We documented an increase in survival and breeding probability as severity of winter decreased. Therefore, a warming climate with less severe winters is likely to promote population viability in this montane frog population. More generally, amphibians and other ectotherms inhabiting alpine or boreal habitats at or near their thermal ecological limits may benefit from the milder winters provided by a warming climate as long as suitable habitats remain intact. A more thorough understanding of how climate change is expected to benefit or harm amphibian populations at different latitudes and elevations is essential for determining the best strategies to conserve viable populations and allow for gene flow and shifts in geographic range.amphibian | climate change | demography | Rana luteiventris | snowpack A mphibian populations are declining around the globe at an alarming rate (1-3), and climate change now figures prominently as a potential interactive driver of some of these declines (4-6). A shift to earlier breeding phenology has been documented in a number of species (7-11), but this shift is not universal across species and has not been tied to population-level consequences. Other work has associated climatic conditions with disease-related declines in the Neotropics (4, 5), yet no mechanisms have been definitively linked to these correlations (12, 13). Reading et al. (14) showed a decrease in adult female body condition and survival in a population of common toads (Bufo bufo) that corresponded with an increase in average annual temperatures. However, these demographic changes were not explicitly linked to changes in population size over time. Kiesecker et al. (15) showed that disease, UV-B, and climate change could interact to increase embryo mortality in western toad (Bufo boreas) populations, yet these populations have not declined. This increased premetamorphic mortality may not be sufficient to cause otherwise increasing populations to decline in the long term. Alternatively, it may be that conditions in short-term or laboratory-based studies are not always representative of long-term patterns in natural populations. To determine mechanisms of population change, we first need to know which vital rates are affected by changes in climate, and then how these changes affect population dynamics.The effects of climate change on growth and survival are particularly relev...

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Section: Discussionmentioning

confidence: 99%

Decreased winter severity increases viability of a montane frog population

McCaffery

Maxell

2010

Proc. Natl. Acad. Sci. U.S.A.

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“…The Klamath and Siskiyou Mountains have been shown to be Pleistocene refugia for many other species [41]. Other amphibians that show genetic signals of refugia in the Klamath Mountains include Western Toad (Anaxyrus boreas; [43]), Tailed Frog (Ascaphus truei [44,45]), Long-toed Salamander (Ambystoma macrodactylum [46]), Pacific Giant Salamander (Dicamptodon tenebrosus [47]), Rough-skinned Newt (Taricha granulosa [48]), Ensatina (Ensatina eschscholtzii [49]), Del Norte Salamander (Plethodon elongatus [16]), Siskiyou Mountains Salamander (Plethodon stormi [16]), and the Scott Bar Salamander (Plethodon asupak [16]). Other taxa that show genetic signatures of Klamath refugia include the Foxtail Pine (Pinus balfouriana [50]), Rockcress (genus Boechera [51]), and the Ariodin Slug (Prophysaon coeruleum [52]).…”

Section: Refugia In the Klamath Mountainsmentioning

confidence: 99%

Genetic Diversity of Black Salamanders (Aneides flavipunctatus) across Watersheds in the Klamath Mountains

et al. 2013

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Abstract:Here we characterize the genetic structure of Black Salamanders (Aneides flavipunctatus) in the Klamath Mountains of northwestern California and southwestern Oregon using mitochondrial and nuclear DNA sequences. We hypothesized that the Sacramento, Smith, Klamath, and Rogue River watersheds would represent distinct genetic populations based on prior ecological results, which suggest that Black Salamanders avoid high elevations such as the ridges that separate watersheds. Our mitochondrial results revealed two major lineages, one in the Sacramento River watershed, and another containing the Klamath, Smith, and Rogue River watersheds. Clustering analyses of our thirteen nuclear loci show the Sacramento watershed population to be genetically distinctive. Populations in the Klamath, Smith, and Rogue watersheds are also distinctive but not as differentiated and their boundaries do not correspond to watersheds. Our historical demographic analyses suggest that the Sacramento population has been isolated from the Klamath populations since the mid-Pleistocene, with negligible subsequent gene flow (2 Nm ≤ 0.1). The Smith and Rogue River watershed populations 658show genetic signals of recent population expansion. These results suggest that the Sacramento River and Klamath River watersheds served as Pleistocene refugia, and that the Rogue and Smith River watersheds were colonized more recently by northward range expansion from the Klamath.

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“…In this study, we sought to explore how microenvironment and prior exposure interact to affect the severity of chytridiomycosis in boreal toads. First, we tested and distinguished the effects of humidity and direct contact with water on disease progression, in order to clarify our earlier findings (Murphy et al 2009), which were potentially confounded by body mass or population (toads were from distinct clades; Goebel et al 2009), and to explore how husbandry influences the outcome of Bd infection. Second, we tested how a moderate temperature increase, within the optimal range for growth of Bd, affects toad survivorship after Bd infection, and examined thermal selection by toads for evidence of behavioral fever.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

Temperature, hydric environment, and prior pathogen exposure alter the experimental severity of chytridiomycosis in boreal toads

Murphy¹,

St‐Hilaire²,

Corn³

2011

Dis. Aquat. Org.

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Prevalence of the pathogen Batrachochytrium dendrobatidis (Bd), implicated in amphibian population declines worldwide, is associated with habitat moisture and temperature, but few studies have varied these factors and measured the response to infection in amphibian hosts. We evaluated how varying humidity, contact with water, and temperature affected the manifestation of chytridiomycosis in boreal toads Anaxyrus (Bufo) boreas boreas and how prior exposure to Bd affects the likelihood of survival after re-exposure, such as may occur seasonally in long-lived species. Humidity did not affect survival or the degree of Bd infection, but a longer time in contact with water increased the likelihood of mortality. After exposure to ~106 Bd zoospores, all toads in continuous contact with water died within 30 d. Moreover, Bd-exposed toads that were disease-free after 64 d under dry conditions, developed lethal chytridiomycosis within 70 d of transfer to wet conditions. Toads in unheated aquaria (mean = 15°C) survived less than 48 d, while those in moderately heated aquaria (mean = 18°C) survived 115 d post-exposure and exhibited behavioral fever, selecting warmer sites across a temperature gradient. We also found benefits of prior Bd infection: previously exposed toads survived 3 times longer than Bd-naïve toads after re-exposure to 10 6 zoospores (89 vs. 30 d), but only when dry microenvironments were available. This study illustrates how the outcome of Bd infection in boreal toads is environmentally dependent: when continuously wet, high reinfection rates may overwhelm defenses, but periodic drying, moderate warming, and previous infection may allow infected toads to extend their survival.KEY WORDS: Boreal toads · Disease severity · Chytridiomycosis · Temperature · Moisture · Acquired immunity Resale or republication not permitted without written consent of the publisherDis Aquat Org 95: 31-42, 2011 32 lethal chytridiomycosis, however, depends not only on Bd, but on the host's immune response. Resistance to Bd has been linked to antimicrobial skin peptides and other hydrophobic molecules (Woodhams et al. 2007, Rollins-Smith et al. 2009) and cutaneous bacteria (Harris et al. 2006), both of which may change in effectiveness depending on body temperature and hydric environment (Matutte et al. 2000, Rollins-Smith et al. 2002.Although the effects of varying temperature on chytridiomycosis have been studied experimentally, the outcomes in vivo have not always been consistent with the temperature optima of Bd in pure culture. For example, Carey et al. (2006) found no difference in survival time in infected boreal toads Anaxyrus boreas boreas housed at 12 and 23°C, although 12°C is well below the optimal growth range of Bd. Likewise, 2 studies have found that moderate changes in temperature within the optimal growth range of Bd (from 17 to 22-23°C) increased survival in exposed amphibians (Andre et al. 2008, Bustamante et al. 2010. Amphibians often modify their body temperature behaviorally, including in response t...

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Mitochondrial DNA evolution in the Anaxyrus boreas species group

Cited by 45 publications

References 99 publications

Decreased winter severity increases viability of a montane frog population

Decreased winter severity increases viability of a montane frog population

Genetic Diversity of Black Salamanders (Aneides flavipunctatus) across Watersheds in the Klamath Mountains

Temperature, hydric environment, and prior pathogen exposure alter the experimental severity of chytridiomycosis in boreal toads

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