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Journal ArticleDOI

Handbook of Frogs and Toads of the United States and Canada.

About: This article is published in American Midland Naturalist.The article was published on 1950-03-01 and is currently open access. It has received 84 citations till now.

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MARINE
Received
Accession
Given by.
Place,



HANDBOOKS
OF
AMERICAN NATURAL HISTORY
edited by
Albert Hazen Wright
Volume
I
HANDBOOK
OF FROGS AND TOADS
by
Anna Allen Wright
Albert Hazen Wright

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Journal ArticleDOI
01 Oct 1999-Ecology
TL;DR: The distributions of amphibian populations (1988-1992) were strongly related to two habitat characteristics: pond hydroperiod and forest canopy cover, and tendencies for ponds to experience population colonizations and extinctions also were associated with pond isolation.
Abstract: From 1988 to 1992 we surveyed the distribution of 14 amphibian species in a set of 37 ponds in southeastern Michigan, USA. Thirty-two of these ponds had been surveyed previously between 1967 and 1974. We found that the distributions of amphibian populations (1988-1992) were strongly related to two habitat characteristics: pond hydroperiod and forest canopy cover. Most species exhibited nonrandom distributions with respect to these pond characteristics. Between surveys, the distribution of each species changed, and most species experienced multiple population colonizations and extinctions. Turnover in the distribution of populations among ponds (estimated via Jaccard's similarity coefficient) averaged nearly 50% among species. The substantial number of species colonizations (40 cases) and extinc- tions (34 cases) between surveys resulted in little net change in number of breeding popu- lations for most species; just four species experienced net changes of more than two popu- lations. Historical information indicated that, for many ponds, hydroperiod and canopy cover changed between surveys. In several cases habitat changes associated with forest succession apparently had negative impacts on amphibian populations. In ponds that now dry each summer and are under closed canopies, two-thirds of the breeding populations present during 1967-1974 were extinct during the recent survey. No population colonizations occurred in these ponds between surveys, in marked contrast to other ponds, in most of which amphibian species richness either was maintained or increased. In addition, tendencies for ponds to experience population colonizations and extinctions also were associated with pond isolation. Our results highlight the volatile nature of amphibian distributions and point to forest suc- cession, via its effects on canopy and hydroperiod, as a potential force shaping the dynamics of amphibian populations.

341 citations

Journal ArticleDOI
TL;DR: The authors used occupancy data collected on 32 species of vertebrates (16 mammals and 16 amphibians) in an agricultural landscape of Indiana, USA, to compare hypotheses that focus on different causal mechanisms underlying interspecific variation in responses to habitat.
Abstract: An ability to predict species' sens- itivities to habitat loss and fragmentation has important conservation implications, and numerous hypotheses have been proposed to explain inter- specific differences observed in human-dominated landscapes. We used occupancy data collected on 32 species of vertebrates (16 mammals and 16 amphibians) in an agricultural landscape of Indiana, USA, to compare hypotheses that focus on different causal mechanisms underlying interspecific variation in responses to habitat

279 citations

Journal ArticleDOI
David M. Green1
TL;DR: Among the populations examined, census declines outnumbered increases yet the average magnitudes for both declines and increases were not demonstrably different, substantiating findings of amphibian decline and giving no support for the idea that amphibian population sizes are dictated by regimes featuring relatively rare years of high recruitment offset by intervening years of gradual decline.

272 citations

Journal ArticleDOI
01 Jul 1978-Ecology
TL;DR: Embryo mortality depended on 9 choice of oviposition sites, which included avoidance of areas with high water temperatures that result in increased developmental abnormalities and preference for areas that increase embryo survival by increasing developmental rate and/or decreasing efficiency of predation on embryos by the leech.
Abstract: Field studies were conducted on factors affecting embryo mortality in bullfrogs, Rana catesbeiana, in 1975 and 1976 at the E. S. George Reserve of the University of Michigan. Larger 9 9 produced significantly larger clutches than smaller 9 9 (6000 to >20,000). Older 9 9 produced 2 clutches each yr with 2nd clutches containing significantly fewer eggs than 1st clutches. Egg size appeared to be unrelated to 9 size; however, 2nd clutches contained significantly smaller eggs than initial clutches for all 9 9. Embryo mortality depended on 9 choice of oviposition sites. Such sites were controlled by territorial 6 6. Larger 66 controlled oviposition sites that had significantly lower embryo mortality than the sites of smaller 6 6. Sources of embryo mortality included developmental abnormalities and predation. Choice of oviposition sites included: (a) avoidance of areas with high water temperatures (>32?C) that result in increased developmental abnormalities and (b) preference for areas that increase embryo survival by increasing developmental rate and/or decreasing efficiency of predation on embryos by the leech, Macrobdella decora.

219 citations

Journal ArticleDOI
TL;DR: The present observations show that the retina of the adult frog may contain as much as 30–40% porphyropsin, all of it segregated in the dorsal zone, which has some ecological importance in increasing the retinal sensitivity to the dimmer and, on occasion, redder light received from below.
Abstract: Though it had been supposed earlier that the bullfrog undergoes a virtually complete metamorphosis of visual systems from vitamin A2 and porphyropsin in the tadpole to vitamin A1 and rhodopsin in the adult, the present observations show that the retina of the adult frog may contain as much as 30–40% porphyropsin, all of it segregated in the dorsal zone. The most dorsal quarter of the adult retina may contain 81–89% porphyropsin mixed with a minor amount of rhodopsin; the ventral half contains only rhodopsin. Further, the dorsal zone contains a two to three times higher concentration of visual pigments than the ventral retina. The pigment epithelium underlying the retina contains a corresponding distribution of vitamins A1 and A2, predominantly vitamin A2 in the dorsal pigment epithelium, exclusively vitamin A1 in the ventral zone. The retina accepts whatever vitamin A the pigment epithelium provides it with, and turns it into the corresponding visual pigment. Thus, a piece of light-adapted dorsal retina laid back on ventral pigment epithelium regenerates rhodopsin, whereas a piece of light-adapted ventral retina laid back on dorsal pigment epithelium regenerates predominantly porphyropsin. Vitamin A2 must be made from vitamin A1, by dehydrogenation at the 3,4-bond in the ring. This conversion must occur in the pigment epithelium, presumably through the action of a vitamin A-3,4-dehydrogenase. The essential change at metamorphosis is to make much less of this dehydrogenase, and to sequester it in the dorsal pigment epithelium. Some adult bullfrogs, perhaps characteristically taken in the summer, contain very little porphyropsin—only perhaps 5%—still sequestered in the dorsal retina. The gradient of light over the retinal surface has little if any effect on this distribution. The greater density of visual pigments in the dorsal retina, and perhaps also—although this is less clear—the presence of porphyropsin in this zone, has some ecological importance in increasing the retinal sensitivity to the dimmer and, on occasion, redder light received from below.

139 citations