The significance of hydroperiod and stand maturity for pool-breeding amphibians in forested landscapes

2006 ◽  
Vol 84 (11) ◽  
pp. 1604-1615 ◽  
Author(s):  
R.F. Baldwin ◽  
A.J.K. Calhoun ◽  
P.G. deMaynadier

The loss of small seasonal wetlands and adjacent forested habitat is a major threat to pool-breeding amphibians in North America. Identifying environmental correlates of breeding effort (and success) in remaining intact landscapes is a critical first step in conservation planning. Little is known about how pool-breeding amphibian populations respond to fine-scale variations in hydroperiod or neighboring forest structure and composition. We studied these associations for wood frogs ( Rana sylvatica LeConte, 1825) and spotted salamanders ( Ambystoma maculatum (Shaw, 1802)) in a forested New England landscape (southern Maine, USA). We conducted egg mass counts across two seasons at 87 strictly seasonal pools. The influence of hydroperiod and landscape (150 and 500 m scales) habitat characteristics on breeding effort were investigated. Pools with longer hydroperiods (≥18 weeks post breeding) that were relatively isolated from other breeding wetlands (<13 neighboring pools within 150 m and <19 within 500 m) supported larger breeding populations of both wood frogs and spotted salamanders. Salamander breeding populations were largest in relatively mature forests. Naturalized, anthropogenic pools supported comparable levels of breeding effort with that of natural pools. Conservation planning for wood frogs and spotted salamanders should incorporate pools at the longer end of the seasonal hydroperiod gradient.

1983 ◽  
Vol 17 (1) ◽  
pp. 70 ◽  
Author(s):  
Bruce Waldman ◽  
Michael J. Ryan
Keyword(s):  
Egg Mass ◽  

2021 ◽  
Author(s):  
Lauren E Frymus ◽  
Debora Goedert ◽  
Francisco Javier Zamora-Camacho ◽  
Peter C Smith ◽  
Caroline J Zeiss ◽  
...  

Human activities have caused massive losses of natural populations across the globe. Like many groups, amphibians have experienced substantial declines worldwide, driven by environmental changes such as habitat conversion, pollution, and disease emergence. Each of these drivers is often found in close association with the presence of roads. Here we report a novel consequence of roads affecting an amphibian native to much of North America, the wood frog (Rana sylvatica). Across 38 populations distributed from southern to central New England, we found that adult wood frogs living adjacent to roads had higher incidence and severity of edema (bloating caused by fluid accumulation) during the breeding season than frogs living away from the influence of roads. This effect was best explained by increased conductivity of breeding ponds, caused by runoff pollution from road salt used for de-icing. Edema severity was negatively correlated with locomotor performance in more northerly populations. Interestingly, northern populations experience more intense winters, which tends to result in more de-icing salt runoff and increased energetic demands associated with overwintering cryoprotection needs. Thus, this emerging consequence of roads appears to impose potential fitness costs associated with locomotion, and these effects might be most impactful on populations living in regions where de-icing is most intense.


2008 ◽  
Vol 86 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Leroy J. Walston ◽  
Stephen J. Mullin

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.


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

1991 ◽  
Vol 69 (7) ◽  
pp. 1963-1968 ◽  
Author(s):  
Richard B. King ◽  
Bethia King

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.


2019 ◽  
Vol 30 (3) ◽  
pp. 658-665 ◽  
Author(s):  
Lindsey Swierk ◽  
Tracy Langkilde

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.


1985 ◽  
Vol 63 (7) ◽  
pp. 1647-1651 ◽  
Author(s):  
Benjamin A. Pierce ◽  
Nalin Sikand

Acid tolerance in wood frog (Rana sylvatica) embryos and larvae was examined in full- and half-sib families. Among the embryos, no significant difference in acid tolerance at pH 3.75 was observed among the progeny of males. At pH 4 only slight differences in embryo acid tolerance existed among the progeny of males mated to the same female. Thus, there is relatively little direct genetic variation in embryo acid tolerance. However, progeny from different females differed significantly in their acid tolerance at both pH 4 and pH 3.75, indicating that maternal factors are important in embryo acid tolerance. Whether these maternal factors are genetic is not known. Among larvae, maternal factors did not appear to influence acid tolerance, but significant genetic variation was present. Larval survival in an acidic solution was not correlated with embryo acid tolerance.


Sign in / Sign up

Export Citation Format

Share Document