Random amplified polymorphic DNA (RAPD) variation among native little bluestem [Schizachyrium scoparium (Michx.) Nash] populations from sites of high and low fertility in forest and grassland biomes

Random amplified polymorphic DNA (RAPD) markers were used to provide estimates of the comparative genetic variation within and among four native populations of Schizachyrium scoparium . Genotypes were collected from high- and low-fertility sites in both New Jersey (forest biome) and in Oklahoma (grassland biome), USA, and propagated in the greenhouse. Four oligonucleotide primers, 10 bp in length, produced a total of 60 RAPD markers, with the minimum marker difference between any two individuals being 14 markers. Euclidean metric distances were calculated among all individuals, and the analysis of molecular variance ( AMOVA ) technique was used to apportion the total genetic variation among individuals within populations, populations within fertility levels, populations within biomes, fertility levels, and biomes. Even though most genetic variation resided within populations, statistically significant differences were detected between populations within each biome. Furthermore, genetic distances between high and low fertility levels within biomes were equal to or greater than biome distances. Therefore, in this wide-ranging and highly variable species, RAPD analysis suggests that local site differences in fertility and ecological history can promote genetic differentiation equal to or greater than geographical differentiation.     

Modelling conservation management options for a southern range‐margin population of Golden Plover Pluvialis apricaria vulnerable to climate change

There is considerable interest in understanding how management may help species and populations cope with climate change (climate change adaptation). I used a population model describing the demography of a southern range‐margin European Golden Plover Pluvialis apricaria population vulnerable to climate change to assess the potential benefits associated with site‐based adaptation management. Two forms of management were simulated: (1) counteracting management to reduce the severity of the negative climate change impacts, simulated by increasing tipulid (cranefly) abundance, and (2) compensatory management to increase populations through an alternative mechanism, simulated by manipulating nest and chick predation rates. A 1 °C rise was estimated to require a doubling of cranefly abundance, or a 35% increase in nest and chick survival rates, to maintain a stable population. For a 2 °C rise, a four‐fold increase in craneflies or an 80% increase in survival rates would be required for population stability. A model based on likely realistic estimates of the magnitude of benefit associated with both adaptation management options showed that combined, they may significantly reduce the severity of population decline and risk of extinction associated with a relatively large increase in temperature of 5.8 °C above 1960–90 levels. Site‐based adaptation management may therefore increase the resistance of Golden Plovers to some degree of future climate change. This model framework for informing climate change adaptation decisions should be developed for other species and habitats.     

The Use of an Escherichia coli Lys- Auxotroph to Assay Nutritionally Available Lysine in Biological Materials

A new bacterial method for determining amino acids in protein foods is described. Instead of the 'natural'microbial auxotrophs e.g. Tetrahymena, Streptococcus , and Leuconostoc , currently used for such assays, an 'artificial'mutant is used, viz. an auxotroph of Escherichia coli . Test proteins (Bovine serum albumin, legume and maize meals) were predigested with a mixture of pronase and intestinal peptidases, the efficiency and extent of proteolysis being monitored by pH stat titration. Final digests were examined by Sephadex gel filtration to ensure that all protein cleavage products were small enough to pass through the E. coli cell wall and to reach its cyto-plasmic amino acid and peptide permeases. The lysine content of the meals, as determined from the growth of an E. coli lysine auxotroph upon the digests, was found to be greater than 90° of the lysine determined chemically in acid hydrolysates. Practical and theoretical advantages of using this latter type of bacterium rather than the fastidious species are discussed. In addition, the particular value of using an intestinal bacterium like E. coli to assay nutritional availability of amino acids is considered in relation to its normal utilization of digested protein foods in vivo , and the similarities between its amino acid and peptide permeases and those of the intestine.     

A New Species of Kinorhynchus (Homalorhagida, Pycnophyidae) from Australia with a Redescription and Range Extension of Other Kinorhyncha from the South Pacific

Kinorhynchus phyllotropis sp.n., from Sydney Harbour, is the first species of the phylum Kinorhyncha to be described from Australian coasts. It appears to be most closely related to K. anomalus (Lang, 1953) from the Chilean coast and possibly, but to a lesser extent, to K. spinosus (Lang, 1949) from the Falkland Islands in the South Atlantic. Kinorhynchus anomalus is rede-scribed and, along with the new species, is compared with the South Atlantic species, the two species known from the Northeast Pacific and the remaining four members of this genus from the North Atlantic, Mediterranean Sea and Black Sea. Cateria styx Gerlach, 1956, is reported from beaches north of Valparaiso, Chile, the first report of this mesopsarnmic cryptorhagid kinorhynch from the Pacific Ocean.