Life Sciences Commons^™

Predicting Risk To Biodiversity As A Function Of Aquifer Pressure In Gab Mound Springs, A. J. Tyre, Brigitte Tenhumberg, H.P. Possingham

School of Biological Sciences: Faculty Publications

Plants and aquatic invertebrates endemic to mound springs of the Great Artesian Basin (GAB) of Australia are of national biodiversity significance. Springs occur in groups, and current survey data suggest that local extinction and recolonisation within a group does occur naturally. Mound spring fauna are therefore good examples of true metapopulations, and any study of the environmental impacts on these systems must take this into account. Use of GAB water leads to drawdown of the pressure in the aquifer. This can potentially impact mound spring flora and fauna in two ways. First, as pressure decreases, so does flow from spring …

A Synopsis Of The Ferns And Fern Allies Of Nebraska, With Maps Of Their Distribution, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland

School of Biological Sciences: Faculty Publications

An annotated list and country-by-country distribution maps are presented for the 32 species of ferns and fern allies native to Nebraska, based upon field and herbarium studies and critical evaluation of the literature. Native to the state are Isoëtes melanopoda, Selaginella rupestris, five species of Equisetum, and 25 species in 18 genera of ferns. Three native species are here verified for the first time, based upon recent collections: Matteuccia struthiopteris var. pensylvanica, Ophioglossum engelmannii, and Pellacaglabella ssp. glabella. Isoëtes melanopoda was rediscovered in 2000, the first record since 1941. Rejected are published reports of …

Biodiversity And Decomposition In Experimental Grassland Ecosystems, Johannes M. H. Knops, David A. Wedin, David Tilman

School of Biological Sciences: Faculty Publications

We examined the impact of biodiversity on litter decomposition in an experiment that manipulated plant species richness. Using biomass originating from the experimental species richness gradient and from a species used as a common substrate, we measured rates of decomposition in litterbags in two locations: in situ in the experiment plots and in an adjacent common garden. This allowed us to separate the effects of litter quality and decomposition location on decomposition. We found that plant species richness had a significant, but minor negative effect on the quality (nitrogen concentration) of the biomass. Neither litter type nor location had a …

Secreted Euryarchaeal Microhalocins Kill Hyperthermophilic Crenarchaea, Cynthia Haseltine, Tiffany Hill, Rafael Montalvo-Rodriguez, Samantha K. Kemper, Richard F. Shand, Paul H. Blum

School of Biological Sciences: Faculty Publications

Few antibiotics targeting members of the archaeal domain are currently available for genetic studies. Since

bacterial antibiotics are frequently directed against competing and related organisms, archaea by analogy

might produce effective antiarchaeal antibiotics. Peptide antibiotic (halocin) preparations from euryarchaeal

halophilic strains S8a, GN101, and TuA4 were found to be toxic for members of the hyperthermophilic

crenarchaeal genus Sulfolobus. No toxicity was evident against representative bacteria or eukarya. Halocin S8

(strain S8a) and halocin R1 (strain GN101) preparations were cytostatic, while halocin A4 (strain TuA4)

preparations were cytocidal. Subsequent studies focused on the use of halocin A4 preparations and Sulfolobus …

Microsatellite Analysis Of Female Mating Behaviour In Lek-Breeding Sage Grouse, Katy Semple, Robert K. Wayne, Robert M. Gibson

School of Biological Sciences: Faculty Publications

We used microsatellite DNA markers to genotype chicks in 10 broods of lek-breeding sage grouse, Centrocercus urophasianus, whose mothers’ behaviour was studied by radio tracking and observing leks. Previous behavioural studies suggested that almost all matings are performed by territorial males on leks and that multiple mating is rare. Two broods (20%) were sired by more than one male. Genetic analyses of the broods of eight females that visited an intensively studied lek were consistent with behavioural observations. Four females observed mating produced singly sired broods and males other than the individual observed copulating were excluded as sires for most …

Mean Time To Extinction Of A Metapopulation With An Allee Effect, Chad Brassil

School of Biological Sciences: Faculty Publications

The incorporation of Allee effects into a simple metapopulation extinction model reveals a large non-linear reduction in mean time to extinction with small changes in an Allee limit. The extent of this reduction is dependent on the level of migration in the metapopulation. With small amounts of migration, small changes in the Allee limit result in large changes in the meantime to extinction. With higher levels of migration, the mean time to extinction is not as sensitive to changes in the Allee limit, becoming more similar to the single population case. The metapopulation modeled here is a set of nine …