59 research outputs found
Molting In The Mature Female Blue-Crab, Callinectes-sapidus Rathbun
The present study examined the hypothesis that mature female blue crabs, Callinectes sapidus, do not enter a terminal anecdysis. Induced molting via eyestalk ablation, size frequency distributions, gonad development and limb regeneration indices from field collected animals are used as indicators of potential post maturity molts. Eyestalk ablation of 15mature females resulted in ecdysis in II individuals approximately 51 days (standard error = 0.64) after ablation, indicating a physiological ability of mature females to complete ecdysis. Analysis of size frequency distributions from catch data indicated two distinct shifts from smaller to larger females, one in early spring and a second in early fall. While migration of larger females into the study area cannot be ruled out, the data suggest molting activity within the sample population. Within the field sample, 11.2% of the animals had regenerating limb buds (R-value = 0.5-5.4). Formation of limb buds is not encountered in species known to have a terminal molt at maturity. These observations suggest that female blue crabs may enter a diapause stage at maturity and some may undergo an additional molt after maturity
Increasing the probability of success in restored forested wetlands
This study investigated survival and growth of two distinct ecotypic populations, with varying tolerance to waterlogging, of four species, Taxodium distichum (L.) Richard, Carpinus caroliniana Walt., Quercus michauxii Nutt. and Quercus pagoda Raf. (Syn. Q.falcata var. pagodifolia Ell.)
An Assessment of Wildlife Utilization between a Man-made Marsh, an Adjacent Natural Marsh, and a Nearby Natural Marsh in Virginia
The present study investigates the functions and values of man-made and natural tidal wetlands. The study is among the first to use simultaneous sampling techniques to investigate animal use preference between man-made and adjacent natural tidal wetlands
The Use of Night-Vision Equipment to observe Wildlife in Forested Wetlands
Urban forested wetlands and rural forested wetlands were studied to investigate the effectiveness of night-vision image intensifier equipment in the observation of medium-to-large animals and to investigate if surrounding landscape type influences wetland habitat value. Bats, cats, dogs, owls, deer, and humans were easily observed using the night-vision equipment. Differences in species use between the rural and urban forested wetland were observed. Light levels and noise levels were significantly higher (
Investigation and long-term monitoring of Phragmites australis within Virginia\u27s constructed wetland sites : final report
The use of constructed wetlands to replace natural wetlands is becoming pandemic. An investigation using Global Positioning System technology to map the vegetated communities of fifteen of the largest constructed wetlands in Virginia reveals that 80% are colonized by the invasive species, Phragmites australis Trin., and/or aggressive species, Typha spp. Tidally influenced wetlands that have subtidal perimeter ditches have significantly less (p\u3c0.05) P. australis in the wetland interior than those without perimeter ditches. Fractured regression analyses show that 6-years after constructionP. australis invasion can be extensive. Linear regression analysis suggests that, if conditions remain favorable for P. australis colonization, constructed wetlands could be overrun in 40 years
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