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Filter Total Items: 3543

Water dispersal of vegetative bulbils of the invasive exotic Dioscorea oppositifolia L. in southern Illinois Water dispersal of vegetative bulbils of the invasive exotic Dioscorea oppositifolia L. in southern Illinois

Riparian corridors promote dispersal of several species of exotic invasives worldwide. Dispersal plays a role in the colonization of exotic invasive species into new areas and this study was conducted to determine if the invasiveness of Dioscorea oppositifolia L. (Chinese yam) is facilitated by secondary dispersal of vegetative diaspores (bulbils) by water. Since seed production of this...
Authors
J.R. Thomas, D.J. Gibson, B.A. Middleton

High resolution mapping and classification of oyster habitats in nearshore Louisiana using sidescan sonar High resolution mapping and classification of oyster habitats in nearshore Louisiana using sidescan sonar

Sidescan sonar holds great promise as a tool to quantitatively depict the distribution and extent of benthic habitats in Louisiana's turbid estuaries. In this study, we describe an effective protocol for acoustic sampling in this environment. We also compared three methods of classification in detail: mean-based thresholding, supervised, and unsupervised techniques to classify sidescan...
Authors
Y.C. Allen, C.A. Wilson, H.H. Roberts, J. Supan

Reproduction and mating behavior of the atlantic flyingfish, Cheilopogon melanurus (Exocoetidae), off North Carolina Reproduction and mating behavior of the atlantic flyingfish, Cheilopogon melanurus (Exocoetidae), off North Carolina

The reproductive biology of Cheilopogon melanurus (Valenciennes, 1847) was examined off North Carolina during the summers of 1991–1992 and 1999–2003. Specimens were collected using a small mesh neuston net and dip nets. A spawning event, the first observation of mating behavior for this species, was recorded off Cape Fear, North Carolina, on 19 August 2003. It was considered to be a...
Authors
Tara L. Casazza, Steve W. Ross, Ann Marie Necaise, Kenneth J. Sulak

Improving removal-based estimates of abundance by sampling a population of spatially distinct subpopulations Improving removal-based estimates of abundance by sampling a population of spatially distinct subpopulations

A statistical modeling framework is described for estimating the abundances of spatially distinct subpopulations of animals surveyed using removal sampling. To illustrate this framework, hierarchical models are developed using the Poisson and negative-binomial distributions to model variation in abundance among subpopulations and using the beta distribution to model variation in capture
Authors
R.M. Dorazio, H.L. Jelks, F. Jordan

Mismatch between herbivore behavior and demographics contributes to scale-dependence of host susceptibility in two pine species Mismatch between herbivore behavior and demographics contributes to scale-dependence of host susceptibility in two pine species

The impacts on forests of tree-killing bark beetles can depend on the species composition of potential host trees. Host susceptibility might be an intrinsic property of tree species, or it might depend on spatial patterning of alternative host species. We compared the susceptibility of loblolly pine (Pinus taeda) and Virginia pine (P. virginiana) to southern pine beetle (Dendroctonus...
Authors
T. Ylioja, D. H. Slone, M.P. Ayres

Primary production in an impounded baldcypress swamp (Taxodium distichum) at the northern limit of the range Primary production in an impounded baldcypress swamp (Taxodium distichum) at the northern limit of the range

The ability of baldcypress (Taxodium distichum)swamps to maintain themselves near the northern limit of their range depends on their levels of production, which is not only are response to climate but also to local environmental factors(e.g., impoundment). We asked if primary production was reduced under impounded conditions and if species' responses to impoundment were individualistic...
Authors
B.A. Middleton, K.L. McKee

Prey vulnerability to peacock cichlids and largemouth bass based on predator gape and prey body depth Prey vulnerability to peacock cichlids and largemouth bass based on predator gape and prey body depth

The interaction of prey fish body depth and predator gape size may produce prey assemblages dominated by invulnerable prey and excessive prey-to-predator biomass ratios. Peacock cichlids (Cichla ocellaris) were stocked into southeast Florida canals to consume excess prey fish biomass, particularly spotted tilapia (Tilapia mariae). The ecomorphologically similar largemouth bass...
Authors
Jeffrey E. Hill, Leo G. Nico, Charles E. Cichra, Carter R. Gilbert
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