Variation in amount of surrounding forest habitat influences the initial orientation of juvenile amphibians emigrating from breeding ponds

2008 ◽  
Vol 86 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Leroy J. Walston ◽  
Stephen J. Mullin
Keyword(s):  
Positive Relationship ◽  
Rana Sylvatica ◽  
Environmental Cues ◽  
Bufo Americanus ◽  
Forest Habitat ◽  
Amphibian Species ◽  
Wood Frogs ◽  
Juvenile Dispersal ◽  
Woodland Ponds ◽  
Emigration Behavior

Juvenile dispersal is important for the persistence of ​amphibian populations. Previous studies have observed nonrandom orientation in juvenile amphibians emigrating from breeding ponds; however, the environmental cues associated with these movements are not well understood. We examined the emigration behavior of recently metamorphosed juveniles of three pond-breeding amphibian species from three woodland ponds. We found that juvenile small-mouthed salamanders ( Ambystoma texanum (Matthes, 1855)), American toads ( Bufo americanus Holbrook, 1836), and wood frogs ( Rana sylvatica LeConte, 1825) exhibited nonrandom orientation upon exiting the breeding ponds. Furthermore, we found a positive relationship between captures of juvenile small-mouthed salamanders and wood frogs and width of the surrounding forest habitat, indicating that these species are selecting areas with broader forested habitat upon exiting the breeding ponds. Our results indicate that migrating juvenile amphibians may rely on direct environmental cues because the orientation of small-mouthed salamanders and wood frogs was influenced by width of the surrounding forested habitat. These observations support previous studies suggesting that maintaining forest habitat, along at least a portion of breeding ponds, is important for the persistence of amphibian populations.

scholarly journals Effects of Road De-Icing Salts on Two Amphibian Species, Rana Sylvatica and Rana Pipiens, and Their Trematode Parasites

2021 ◽  
Author(s):  
Dino Milotic
Keyword(s):  
Rana Sylvatica ◽  
Amphibian Declines ◽  
High Salt ◽  
Amphibian Species ◽  
Wood Frogs ◽  
Leopard Frogs ◽  
Larval Amphibians ◽  
Potential Contaminant ◽  
Northern Leopard Frogs ◽  
Host Parasite

With ongoing amphibian declines, it is essential to determine possible contributors such as diseases and environmental contaminants that may increase susceptibility. A potential contaminant is road salt (mainly NaCl), which leaches into aquatic environments. I examined whether road salts make larval amphibians (tadpoles) more susceptible to trematode parasite infection, and also how these affect free-living trematode infectious stages (cercariae). I exposed Rana sylvatica (wood frogs) and R. pipiens (northern leopard frogs) to control, medium (400 mg/L), and high salt (800 mg/L) treatments, and then to trematodes. High salt tended to reduce wood frog anti-parasite behaviour and resistance to infection but the opposite was seen for R. pipiens, although these tadpoles had elevated lymphocyte counts in high salinity. Trematodes were differentially affected by increased salinities. The results suggest that host-parasite-environment interactions are complex, with species differentially affected by contaminants, which may lead to community shifts in predominant hosts and parasite species.

scholarly journals Effects of Road De-Icing Salts on Two Amphibian Species, Rana Sylvatica and Rana Pipiens, and Their Trematode Parasites

2021 ◽  
Author(s):  
Dino Milotic
Keyword(s):  
Rana Sylvatica ◽  
Amphibian Declines ◽  
High Salt ◽  
Amphibian Species ◽  
Wood Frogs ◽  
Leopard Frogs ◽  
Larval Amphibians ◽  
Potential Contaminant ◽  
Northern Leopard Frogs ◽  
Host Parasite

With ongoing amphibian declines, it is essential to determine possible contributors such as diseases and environmental contaminants that may increase susceptibility. A potential contaminant is road salt (mainly NaCl), which leaches into aquatic environments. I examined whether road salts make larval amphibians (tadpoles) more susceptible to trematode parasite infection, and also how these affect free-living trematode infectious stages (cercariae). I exposed Rana sylvatica (wood frogs) and R. pipiens (northern leopard frogs) to control, medium (400 mg/L), and high salt (800 mg/L) treatments, and then to trematodes. High salt tended to reduce wood frog anti-parasite behaviour and resistance to infection but the opposite was seen for R. pipiens, although these tadpoles had elevated lymphocyte counts in high salinity. Trematodes were differentially affected by increased salinities. The results suggest that host-parasite-environment interactions are complex, with species differentially affected by contaminants, which may lead to community shifts in predominant hosts and parasite species.

Acidity and associated water chemistry of amphibian habitats in Nova Scotia

1985 ◽  
Vol 63 (1) ◽  
pp. 97-105 ◽  
Author(s):  
J. M. Dale ◽  
B. Freedman ◽  
J. Kerekes
Keyword(s):  
Nova Scotia ◽  
Rana Catesbeiana ◽  
Function Analysis ◽  
Acid Tolerance ◽  
Rana Sylvatica ◽  
Rana Clamitans ◽  
Bufo Americanus ◽  
Amphibian Species ◽  
Species Groups ◽  
Field Transplant

One hundred and fifty-nine field sites consisting of ditches, bogs, marshes, ponds, and lakes in south and central Nova Scotia were surveyed for the presence of the adults, eggs, or larvae of 11 amphibian species. Water samples were analyzed for pH, alkalinity, color, conductivity, Na, K, Mg, Ca, SO4, and Cl. Discriminant function analysis revealed that none of these variables predicted a species' presence. Two three-species groups were found to be significantly associated among themselves, but mutually exclusive of each other. The two groups were (i) Ambystoma maculatum, Hyla crucifer, and Rana sylvatica and (ii) Rana clamitans, Rana catesbeiana, and Rana palustris. Rana sylvatica and A. maculatum were observed breeding successfully in an acidic bog (mean pH 4.1). Rana clamitans adults and larvae were located in the field at pHs as low as 3.5 and 3.9, respectively. Field transplant studies, using eggs of A. maculatum and R. sylvatica (at pH 5.7 and 4.1) and Bufo americanus (at pH 6.3 and 4.1), revealed that R. sylvatica was least sensitive to acidity. There is considerable variation in acid tolerance among the various species of Nova Scotia amphibians. Nevertheless, successful breeding by some species is occurring at very low pHs.

scholarly journals Mitochondria and the Frozen Frog

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 543
Author(s):  
Janet M. Storey ◽  
Shaobo Wu ◽  
Kenneth B. Storey
Keyword(s):  
Cell Volume ◽  
Ischemia Reperfusion ◽  
Enzyme Regulation ◽  
Rana Sylvatica ◽  
Volume Reduction ◽  
Whole Body ◽  
Amphibian Species ◽  
Wood Frogs ◽  
16S Rna ◽  
Total Body

The wood frog, Rana sylvatica, is the best-studied of a small group of amphibian species that survive whole body freezing during the winter months. These frogs endure the freezing of 65–70% of their total body water in extracellular ice masses. They have implemented multiple adaptations that manage ice formation, deal with freeze-induced ischemia/reperfusion stress, limit cell volume reduction with the production of small molecule cryoprotectants (glucose, urea) and adjust a wide variety of metabolic pathways for prolonged life in a frozen state. All organs, tissues, cells and intracellular organelles are affected by freeze/thaw and its consequences. This article explores mitochondria in the frozen frog with a focus on both the consequences of freezing (e.g., anoxia/ischemia, cell volume reduction) and mitigating defenses (e.g., antioxidants, chaperone proteins, upregulation of mitochondria-encoded genes, enzyme regulation, etc.) in order to identify adaptive strategies that defend and adapt mitochondria in animals that can be frozen for six months or more every year. A particular focus is placed on freeze-responsive genes in wood frogs that are encoded on the mitochondrial genome including ATP6/8, ND4 and 16S RNA. These were strongly up-regulated during whole body freezing (24 h at −2.5 °C) in the liver and brain but showed opposing responses to two component stresses: strong upregulation in response to anoxia but no response to dehydration stress. This indicates that freeze-responsive upregulation of mitochondria-encoded genes is triggered by declining oxygen and likely has an adaptive function in supporting cellular energetics under indeterminate lengths of whole body freezing.

Patterns of larval amphibian distribution along a wetland hydroperiod gradient

2003 ◽  
Vol 81 (9) ◽  
pp. 1539-1552 ◽  
Author(s):  
Kimberly J Babbitt ◽  
Matthew J Baber ◽  
Tracy L Tarr
Keyword(s):  
Species Richness ◽  
Rana Catesbeiana ◽  
Rana Sylvatica ◽  
Predatory Fish ◽  
Bufo Americanus ◽  
Amphibian Species ◽  
Larval Amphibians ◽  
Pseudacris Crucifer ◽  
Wetland Hydroperiod ◽  
Species Richness And Abundance

We investigated the response of pond-breeding amphibian assemblages to wetland hydroperiod and associated predator changes (invertebrates (abundance and richness) and fish (presence/absence)) in relatively undisturbed landscapes in southern New Hampshire, U.S.A. We sampled 42 wetlands for larval amphibians in 14 spatial blocks (each with a short-, intermediate-, and permanent-hydroperiod wetland) in 1998 and 1999. Assemblages in short-hydroperiod wetlands (<4 months) were depauperate (4 species only) compared with intermediate-hydroperiod (non-permanent but >4 months) and permanent wetlands, which included 7 and 9 species, respectively. Total amphibian abundance did not vary among hydroperiod categories. Species distributions along the hydrological gradient also differed. Rana sylvatica dominated wetlands with short and intermediate hydroperiods, whereas Rana catesbeiana, Bufo americanus, Rana clamitans, and Pseudacris crucifer dominated in those with a longer hydroperiod. Among permanent wetlands, amphibian species richness and abundance did not differ with respect to the presence of predatory fish, although there were species-compositional differences. Amphibian species richness and abundance were positively correlated with the abundance and richness of predatory invertebrates, suggesting that both amphibian and macroinvertebrate predator assemblages may be responding similarly to differences in wetland characteristics (e.g., dissolved oxygen concentration). Overall, our results indicate that wetland hydroperiod has an important influence on amphibian distribution and should be incorporated into regulations and legislation designed to protect biologically diverse isolated wetlands.

Effects of elevated hydrogen ion and aluminum concentrations on the survival of amphibian embryos and larvae

1985 ◽  
Vol 63 (1) ◽  
pp. 116-123 ◽  
Author(s):  
Karen L. Clark ◽  
Ronald J. Hall
Keyword(s):  
Hatching Success ◽  
Rana Sylvatica ◽  
Larval Survival ◽  
Hydrogen Ion ◽  
Ph Effects ◽  
Bufo Americanus ◽  
Amphibian Species ◽  
Egg Hatching ◽  
Effects Of Ph ◽  
Chemical Variable

Egg hatching success was measured for three amphibian species (Bufo americanus, Rana sylvatica, and Ambystoma maculatum) exposed to varying hydrogen ion, aluminum, and dissolved organic carbon (DOC) concentrations. In the first experiment, hatching success in six stream pools was negatively correlated with Al and DOC and positively correlated with pH. Effects of any one chemical variable, however, could not be separated from the others. In a second experiment, to separate effects of pH and Al from DOC, eggs and larvae were exposed to simulated stream pools in which pH was reduced. At pH 4.8 and 37 μg/L inorganic monomeric Al, only eggs of A. maculatum were affected. At pH 4.3, 46 μg/L inorganic monomeric Al was more toxic (compared with 34–35 μg/L at pH 4.8 and 4.3) to B. americanus and R. sylvatica embryos. Bufo americanus was more sensitive to low pH and elevated Al than R. sylvatica. Mortality of eggs of both species mainly occurred within 1 day of exposure but continued until hatching. Mortality of A. maculatum eggs, however, did not occur during the 4 days of acidification, but 2–3 weeks later, at the time of hatching. Larval survival in general was not affected by reduced pH (pH 4.3) and (or) elevated Al (up to 46 μg/L inorganic monomeric Al).

Kin recognition by larval wood frogs (Rana sylvatica): effects of diet and prior exposure to conspecifics

Oecologia ◽  
1991 ◽  
Vol 86 (3) ◽  
pp. 319-324 ◽  
Author(s):  
George J. Gamboa ◽  
Keith A. Berven ◽  
Randy A. Schemidt ◽  
Thomas G. Fishwild ◽  
Kelli M. Jankens
Keyword(s):  
Kin Recognition ◽  
Rana Sylvatica ◽  
Prior Exposure ◽  
Wood Frogs

Sexual differences in color and color change in wood frogs

1991 ◽  
Vol 69 (7) ◽  
pp. 1963-1968 ◽  
Author(s):  
Richard B. King ◽  
Bethia King
Keyword(s):  
Color Change ◽  
Red Light ◽  
Green Light ◽  
Rana Sylvatica ◽  
Sexual Differences ◽  
Wood Frog ◽  
Color Classification ◽  
Wood Frogs ◽  
Evolutionary Response ◽  
Males And Females

An observer-free method of color classification was used to determine whether wood frogs, Rana sylvatica, exhibit sexual differences in color and color change. Males and females captured from breeding aggregations differed significantly in color: females reflected a greater amount of long-wavelength (yellow–red) light and less short-wavelength (blue–green) light than males. The color difference was not just a result of differences in the state of physiological color change at the time of capture but persisted for a month after capture. Males and females also differed in their color-change responses to black and white backgrounds: both sexes changed in brightness, but only males changed in the relative amount of light reflected at different wavelengths. Wood frog color may function in predator avoidance through crypsis. There was a good match between frogs and some of the leaves from the leaf litter surrounding the breeding ponds. Hypotheses for the development of sexual differences in wood frog color include sexual differences in availability of pigment and pigment precursors, morphological color change, and evolutionary response to different selection pressures.

scholarly journals Fitness costs of mating with preferred females in a scramble mating system

2019 ◽  
Vol 30 (3) ◽  
pp. 658-665 ◽  
Author(s):  
Lindsey Swierk ◽  
Tracy Langkilde
Keyword(s):  
Mate Choice ◽  
Mating Systems ◽  
Rana Sylvatica ◽  
Female Offspring ◽  
Operational Sex Ratio ◽  
Male Choice ◽  
Wood Frogs ◽  
Multiple Parameters ◽  
Fitness Benefits ◽  
Male Mate

Abstract Little is known about the operation of male mate choice in systems with perceived high costs to male choosiness. Scramble mating systems are one type of system in which male choice is often considered too costly to be selected. However, in many scramble mating systems, there are also potentially high rewards of male choosiness, as females vary dramatically in reproductive output and males typically mate once per season and/or per lifetime. Using scramble mating wood frogs (Rana sylvatica), we tested whether males gain fitness benefits by mating with preferred females. We conducted choice trials (1 male presented simultaneously with 2 females) and permitted males to mate with their preferred or nonpreferred female. Offspring of preferred and nonpreferred females were reared in the laboratory and field, and we quantified various fitness-relevant parameters, including survivorship and growth rates. Across multiple parameters measured, matings with preferred females produced fewer and lower-quality offspring than did those with nonpreferred females. Our results are inconsistent with the idea that mate choice confers benefits on the choosing sex. We instead propose that, in scramble systems, males will be more likely to amplex females that are easier to capture, which may correlate with lower quality but increases male likelihood of successfully mating. Such male choice may not favor increased fitness when the operational sex ratio is less biased toward males in scramble mating systems but is, instead, a bet-hedging tactic benefitting males when available females are limited.

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