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

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.

2003 ◽  
Vol 81 (9) ◽  
pp. 1539-1552 ◽  
Author(s):  
Kimberly J Babbitt ◽  
Matthew J Baber ◽  
Tracy L Tarr

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.


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.


1989 ◽  
Vol 67 (7) ◽  
pp. 1686-1689 ◽  
Author(s):  
G. J. Chen ◽  
S. S. Desser

During June and July of 1988, 264 amphibians from Algonquin Park, Ontario, were examined for eimeriid coccidian parasites; the species examined were Rana catesbeiana Shaw, Rana clamitans Latreille, Rana septentrionalis Baird, and Rana sylvatica LeConte. Two distinct types of oocysts were observed in the feces of the frogs. The highest prevalence of infection was recorded from young adult frogs and two new species of Eimeria are described from these animals. Oocysts of Eimeria algonquini n.sp. are spherical, 15.8 (14.5–16.1) μm in diameter, with a thin single-layered wall; micropyle and polar granule absent; large granular oocyst residuum present. Sporocysts banana-shaped, 19.5 (18.7–20.4) × 4.2 (3.8–4.6) μm with prominent granular residuum; Stieda body absent. Oocysts of Eimeria kermiti n.sp. are ovoid, 25.1 (24.7–26.6) × 19.5 (17.6–20.1) μm with thin single-layered wall; polar granule present; micropyle absent; large granular oocyst residuum present. Sporocysts ovoid, 9.9 (9.3–10.4) × 6.6 (6.0–7.1) μm with Stieda body and prominent granular residuum.


1982 ◽  
Vol 60 (2) ◽  
pp. 116-123 ◽  
Author(s):  
Brian O. Reilly ◽  
P. T. K. Woo

From May 1979 to July 1980, the blood of 196 mature Hyla versicolor LeConte from six sites in southern Ontario and southeastern Manitoba was examined for trypanosomes using the haematocrit centrifugation technique. Trypanosoma andersoni n. sp. and Trypanosoma grylli Nigrelli were found in 5.2 and 5.6% of the frogs examined. Three frogs (1.5%) were infected with both species of trypanosomes. Blood trypomastigotes of both species were monomorphic. Blood trypomastigotes of T. andersoni n. sp. were long and slender, tapering at both ends, whereas those of T. grylli were pyriform with a rounded posterior and tapered anterior.Both blood and culture forms of these trypanosomes were infective to laboratory-raised H. versicolor and Hyla crucifer Wied. Trypanosoma grylli was also infective to a field-collected Acris gryllus (LeConte). Neither trypanosome was infective to laboratory-raised Rana catesbeiana Shaw, Rana clamitans Rafinesque tadpoles, Rana pipiens Schreber, Rana sylvatica LeConte, or Xenopus laevis Daudin. Trypanosoma andersoni n. sp. was also not infective to laboratory-raised Bufo americanus Holbrook, Pseudacris triseriata (Wied), or to field-collected Hyla cinerea (Schneider) and Osteopilus septentrionalis Dumeril and Bibron. Neither species was infective to field-collected Notophthalmus viridescens (Rafinesque).


1985 ◽  
Vol 63 (1) ◽  
pp. 116-123 ◽  
Author(s):  
Karen L. Clark ◽  
Ronald J. Hall

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).


1989 ◽  
Vol 144 (1) ◽  
pp. 215-233 ◽  
Author(s):  
CHRIS M. WOOD ◽  
R. S. MUNGER ◽  
D. P. TOEWS

In theory, the distribution of ammonia across cell membranes (Tammi/Tamme) between intracellular and extracellular fluids (ICF and ECF) may be determined by the transmembrane pH gradient (as in mammals), the transmembrane potential (as in teleost fish), or both, depending on the relative permeability of the membranes to NH3 and NH4+ (pNH3/pNH4+). The resting distributions of H+ (via [14C]DMO), ammonia and urea between plasma and skeletal muscle, and the relative excretion rates of ammonia-N and urea-N, were measured in five amphibian species (Bufo marinus, Ambystoma tigrinum, Rana catesbeiana, Necturus maculosus and Xenopus laevis). Although ureai/ureae ratios were uniformly close to 1.0, Tammi/Tamme. ratios correlated directly with the degree of ammoniotelism in each species, ranging from 9.1 (Bufo, 10% ammoniotelic) to 16.7 (Xenopus, 79% ammoniotelic). These values are intermediate between ratios of about 30 (low pNH3/pNH4+) in ammoniotelic teleost fish and about 3 (high pNH3/pNH4+) in ureotelic mammals. The results indicate that amphibians represent a transitional stage in which ammonia distribution is influenced by both the pHi-pHe gradient and the membrane potential, and that a reduction in cell membrane permeability to NH4+ (i.e. increased pNH3/pNH4+) was associated with the evolution of ureotelism. Hyperosmotic saline exposure increased urea excretion 10-fold in Xenopus, while ammonia excretion remained unchanged. Tammi/Tamme fell, but this response was attributable to an abolition of the pHi-pHe gradient, rather than a physiological change in the cell membrane pNH3/pNH4+.


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.


1981 ◽  
Vol 59 (9) ◽  
pp. 1836-1846 ◽  
Author(s):  
Murray J. Kennedy

Previous experimental and field studies have shown that variations within the genus Haematoloechus may result from differences in age and degree of maturity, extent of crowding, species of host, and other factors.Based on these observations, only 6 of the 15 previously known species from Canada and the United States are considered valid. The valid species and their synonyms are as follows: Haematoloechus longiplexus Stafford, 1902; H. breviplexus Stafford, 1902; H. varioplexus Stafford, 1902 (= H. parviplexus, = H. buttensis, = H. similiplexus, = H. floedae, and H. uniplexus); H. kernensis Ingles, 1932 (= H. tumidus); H. medioplexus Stafford, 1902; and H. complexus (Seely, 1906) (= H. coloradensis, = H. confusus, = H. oxyorchis).The existence of three species groups is hypothesized. Haematoloechus longiplexus and H. breviplexus constitute one group, characterized by little geographical variation and a narrow host range. They are typically parasites of Rana catesbeiana and R. clamitans. Haematoloechus varioplexus and H. kernensis constitute the second group. These species have a wider host range and greater variation in characters purported to be specific differences. The third group includes those lung flukes which do not contain extracaecal loops (H. medioplexus and H. complexus). Of these, only H. medioplexus had little geographical variation and was found to occur in a single frog host.


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