scholarly journals The amphibians and reptiles of the Altamaha River, Georgia

2012 ◽  
Vol 19 (3) ◽  
pp. 170-186
Author(s):  
Dirk J. Stevenson ◽  
Jill Stackhouse

Field surveys of 59 sites conducted in 1999–2012 and a review of existing museum specimens documented 29 species of amphibians (13 salamanders, 16 anurans) and 36 species of reptiles (1 crocodilian, 5 lizards, 19 snakes, 11 turtles) from the Altamaha River, Georgia and lowland habitats within its associated floodplain. Field sampling methods including visual encounter surveys, dipnetting, frog call surveys, and binocular/canoe/swim surveys for turtles. All were conducted in several distinct habitat types: The river mainstem, the river floodplain (which includes bottom-land hardwood forest, alluvial swamps, and oxbow lakes), and perennial seepages associated with north-facing bluffs. Biogeographically, the Altamaha River is a notable influence on the distributions of many amphibians and reptiles. Pitvipers are mostly absent in floodplain habitats along the river; the absence of what is generally perceived as a common semi-aquatic viper (Cotttonmouth, Agkistrodon piscivorus) from floodplain wetlands along much of the Altamaha River is intriguing and merits further study. Continued investigations and regular monitoring of reptilian and amphibian populations along the Altamaha River, a remarkable Coastal Plain stream and a wilderness waterway par excellence, are warranted.

1998 ◽  
Vol 55 (8) ◽  
pp. 1983-1995 ◽  
Author(s):  
David R Bernard ◽  
Robert P Marshall ◽  
John E Clark

Methods are presented for planning individual catch-sampling, tagging, and field-sampling programs to estimate salmon (Oncorhynchus spp.) harvest in recreational and commercial fisheries from several hatchery-produced and wild cohorts through recovery of coded-wire tags. We show how to determine sample sizes sufficiently large to detect harvest and link sample sizes to expenditures through linear and allometric cost functions to determine optimal tagging and catch-sampling rates. Sample sizes that will minimize bias and variance are charted for field-sampling programs designed to estimate the fraction of a cohort with tags. We describe sampling strategies that can be used to detect or to minimize bias in harvest estimates from tag loss, tag-induced mortality, tag-induced straying, and nonrandom sampling. Methods are demonstrated with data on cohorts of chinook (O. tshawytscha) and coho salmon (O. kisutch) from Alaska.


2012 ◽  
Vol 58 (5) ◽  
pp. 513-522 ◽  
Author(s):  
Luke Worsham ◽  
Daniel Markewitz ◽  
Nathan P. Nibbelink ◽  
Larry T. West

2015 ◽  
Vol 21 (1) ◽  
pp. 63-69
Author(s):  
Christopher A. Taylor ◽  
Bryan S. Engelbert ◽  
Robert J. DiStefano

Abstract We conducted a study to investigate methods to assess crayfish populations typically found in low gradient, lentic, floodplain habitats in Missouri. We used a random site selection process that allowed us to capture all known species from this region of Missouri. We compared two sampling methods for primary burrowing crayfishes at our sampling sites: hook-and-line capture technique and burrow excavation. Adjacent standing water habitats at sites were also sampled using a timed search method. Hook-and-line capture success was substantially less than reported in the literature (0.7% versus 80%), while burrow excavation was higher than reported (64% versus 40.7%). We successfully captured six crayfish species using burrow excavation, whereas lentic timed search sampling captured nine species in adjacent standing waters at our sampling sites. Our results suggest that additional efforts sampling lentic habitats rather than additional time searching for and excavating burrows is more likely to capture total community richness. We found a seasonal influence on burrow occupancy surveys, as Julian day was positively correlated to finding active crayfish burrows. Crayfish capture in standing water was positively affected by soil temperature, and negatively correlated to Julian day.


2019 ◽  
Vol 97 (5) ◽  
pp. 479-487
Author(s):  
J.E. Colm ◽  
N.E. Mandrak ◽  
B.L. Tufts

We investigated patterns of grass pickerel (Esox americanus vermiculatus Lesueur, 1846) distribution in three watersheds in Ontario, Canada, using site- and reach-scale habitat variables and fish community assemblage data to determine why this species occurs sporadically throughout watersheds despite abundant seemingly suitable, but unoccupied, habitat. Habitat and fish community data were collected using conventional field sampling methods, and reach-scale habitat data were compiled with the aid of a geographic information system. We found that occupied sites had lower baseflow indices and reach slopes but higher conductivity and agricultural land uses than unoccupied sites. More grass pickerel were detected when conductivity, channel cover, and wetlands in the floodplain were highest and bank slopes lowest; this is consistent with habitat preferences described elsewhere in its range. Habitat features at the site scale appeared more important than reach-scale features suggesting that grass pickerel may be using small habitat patches. This study identifies habitat elements important to grass pickerel and offers insights into management implications.


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