scholarly journals Review and reinterpretation of Rio Grande silvery minnow reproductive ecology using egg biology, life history, hydrology, and geomorphology information

Ecohydrology ◽  
2013 ◽  
Vol 6 (3) ◽  
pp. 491-505 ◽  
Author(s):  
Carl Nicolas Medley ◽  
Patrick D. Shirey
Keyword(s):  
Life History ◽  
Reproductive Ecology ◽  
Rio Grande ◽  
Rio Grande Silvery Minnow

Reproductive Ecology of The Allied Rock-wallaby, Petrogale assimilis.

1996 ◽  
Vol 19 (2) ◽  
pp. 209
Author(s):  
R. Delaney
Keyword(s):  
Life History ◽  
Sex Ratio ◽  
Sexual Maturity ◽  
Post Partum ◽  
Reproductive Ecology ◽  
Oestrous Cycle ◽  
Embryonic Diapause ◽  
Minimum Age

Petrogale assimilis has a typical life history and reproductive ecology for a macropodid of its size. Both sexes are capable of reproducing continuously; gestation is about the same length as the oestrous cycle (approximately one month); a single young is born and, a post-partum oestrus and embryonic diapause probably occurs. The sex ratio of young is unbiased. Pouch young remain permanently attached to the teat until 110 - 143 days (n=11). Permanent exit from the pouch occurs at 180 - 231 days (mean=201 days, n=25), and weaning occurs between 267 - 387 days (n=5). Sexual maturity occurs at a minimum age of 17.5 months in females and 23 months in males.

Reproductive Ecology and Life History of Female Sonoran Desert Tortoises (Gopherus morafkai)

2018 ◽  
Vol 32 (1) ◽  
pp. 34-50 ◽  
Author(s):  
Roy C. Averill-Murray ◽  
Terry E. Christopher ◽  
Brian T. Henen
Keyword(s):  
Life History ◽  
Sonoran Desert ◽  
Reproductive Ecology ◽  
Gopherus Morafkai ◽  
History Of

Life history and reproductive ecology of White's skink, Egernia whitii

2005 ◽  
Vol 53 (6) ◽  
pp. 353 ◽  
Author(s):  
DG Chapple
Keyword(s):  
Life History ◽  
Litter Size ◽  
Reproductive Ecology ◽  
Climatic Conditions ◽  
Colour Pattern ◽  
Offspring Size ◽  
Adult Sex Ratio ◽  
Pattern Polymorphism ◽  
Comparison Of The Results ◽  
Colour Morphs

The life history and reproductive ecology of White’s skink, Egernia whitii, was examined in a population in the Australian Capital Territory using both field and genetic studies. Colour pattern polymorphism was evident within the population, with both patterned and plain-back morphs present. Lizards typically took 3 years to reach sexual maturity, with the size at maturity being ~75 mm snout–vent length (SVL) in both sexes. There was an even overall adult sex ratio, although a slight female-bias was evident in plain-back individuals. Sexual dimorphism was evident, with males having longer and wider heads, and females having larger body size. Females generally bred annually, with mating occurring in September–October and parturition in late January–February, although the litter was produced over several days (2–10 days, mean 4 days). Litter size ranged from one to four (mean of 2.5). There was a significant relationship between maternal SVL and both litter size and relative clutch mass, but these trends were not consistent between colour morphs. An inverse relationship between litter size and offspring size (SVL and mass) was found. Comparison of the results with previous investigations of E. whitii indicates substantial geographic variation in life-history traits that is presumably associated with latitudinal variation in climatic conditions.

The genus Pseudis (Anura: Pseudidae) in Rio Grande do Sul, southern Brazil, with description of a new species

2000 ◽  
Vol 21 (1) ◽  
pp. 39-55 ◽  
Author(s):  
Axel Kwet
Keyword(s):  
Life History ◽  
New Species ◽  
Rio Grande ◽  
Advertisement Call ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Body Coloration ◽  
The Family ◽  
A New Species

AbstractA new species of Pseudis is described from São Francisco de Paula, Rio Grande do Sul, Brazil. It is known from the southern parts of the Serra Geral where it occurs in grassland, inhabiting permanent ponds and still-water zones of slow flowing creeks. It is characterized by a paired vocal sac and a bulbous thumb, considerably widened at the base. It is distinguished from P. minutus by its different call, body coloration, rounded snout, and a more robust body with shorter hindlimbs. Advertisement call, tadpole, and life history are described. The taxonomy of the family Pseudidae in Rio Grande do Sul is discussed, supporting the synonymy of Lysapsus mantidactylus and P. meridionalis with P. minutus.

scholarly journals Fish Rescue during Streamflow Intermittency May Not Be Effective for Conservation of Rio Grande Silvery Minnow

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3371
Author(s):  
Thomas P. Archdeacon ◽  
Tracy A. Diver ◽  
Justin K. Reale
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Fish Assemblages ◽  
Sublethal Effects ◽  
Rio Grande ◽  
Quality Data ◽  
Water Quality Data ◽  
Low Dissolved Oxygen ◽  
Rio Grande Silvery Minnow ◽  
Oxygen Concentrations

Streamflow intermittency can reshape fish assemblages and present challenges to recovery of imperiled species. During streamflow intermittency, fish can be subjected to a variety of stressors, including exposure to crowding, high water temperatures, and low dissolved oxygen, resulting in sublethal effects or mortality. Rescue of fishes is often used as a conservation tool to mitigate the negative impacts of streamflow intermittency. The effectiveness of such actions is rarely evaluated. Here, we use multi-year water quality data collected from isolated pools during rescue of Rio Grande silvery minnow Hybognathus amarus, an endangered minnow. We examined seasonal and diel water quality patterns to determine if fishes are exposed to sublethal and critical water temperatures or dissolved oxygen concentrations during streamflow intermittency. Further, we determined survival of rescued Rio Grande silvery minnow for 3–5 weeks post-rescue. We found that isolated pool temperatures were much warmer (>40 °C in some pools) compared to upstream perennial flows, and had larger diel fluctuations, >10 °C compared to ~5 °C, and many pools had critically low dissolved oxygen concentrations. Survival of fish rescued from isolated pools during warmer months was <10%. Reactive conservation actions such as fish rescue are often costly, and in the case of Rio Grande silvery minnow, likely ineffective. Effective conservation of fishes threatened by streamflow intermittency should focus on restoring natural flow regimes that restore the natural processes under which fishes evolved.

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