Paleoecological reconstruction of changes in the productivity of a small,meromictic lake in Southern Ontario,Canada

Some aspects of the paleoproductivity of meromictic Crawford Lake, near Toronto, are inferred from a study of its sedimentary pigments, and diatoms. Several stages of lake development are observed over the 35 cm-deep sediment core removed from the center of Crawford Lake. Evidence of changes in lake productivity during the last 300 years was reflected by significant stratigraphic sediment pigment changes which were associated with European settlement in the Crawford Lake watershed and recent alterations associated with the area's operation by the Conservation Authority (1969 — present). One of the most important factors correlated with paleoproductivity was land clearance (mainly logging of white oak and pine). Deforestation during the last century is correlated with an increase in the amount of algal pigments deposited in the lake's sediments during the 1800's. During the last 10 years a striking increase in the accumulation of chlorophyll derivatives was observed. This is correlated with a dramatic increase in the number of visitors to the lake.Stratigraphic changes in the ratio of cyanobacterial to phototrophic bacterial pigment accumulation are used to infer changes which occurred during the shift from mesotrophy to eutrophy in Crawford Lake.     

Sex ratio and intrasexual kin competition in mammals

Summary Asymmetries in both intrasexual competition and generation overlap occur in Antechinus (Dasyuridae; Marsupialia). We show that the range of interpopulation variation in the sex ratio of pouch young spans and exceeds the range of sex ratios at birth hitherto recorded from eutherians (Clutton-Brock and Albon 1983). Although postweaning dispersal and male mortality are similar among all Antechinus populations, interpopulation variance in female longevity leads to variable duration of mother/daughter interaction. As this duration increases, parental investment is increasingly biased toward males, supporting the view that local competition among female kin for resources may influence mammalian sex ratios.     

Isolation, characterization, and expression of a second beta-tubulin-encoding gene from Colletotrichum gloeosporioides f. sp. aeschynomene.

Colletotrichum gloeosporioides f. sp. aeschynomene is a fungal plant pathogen of Aeschynomene virginica. A beta-tubulin-encoding gene (TUB2) from this pathogen was cloned and sequenced. The deduced amino acid sequence of TUB2 had a high degree of homology to other fungal beta-tubulins. A portion of TUB2 from a benomyl-resistant C. gloeosporioides f. sp. aeschynomene mutant was also cloned and sequenced. A point mutation resulting in a glutamic acid-to-lysine substitution at amino acid 198 likely confers benomyl resistance. The mutation is relevant for use as a selectable marker in developing a gene transfer system in C. gloeosporioides f. sp. aeschynomene. Northern (RNA) hybridizations with C. gloeosporioides f. sp. aeschynomene TUB2 and another C. gloeosporioides f. sp. aeschynomene beta-tubulin-encoding gene (TUB1) as probes showed differential expression of these genes in different cell types.     

Commensal and mutualistic interactions among terrestrial vertebrates

Although overlooked in many field studies, commensal and mutualistic interactions occur frequently between species of terrestrial vertebrates. Potential advantages for individuals in mixed-species associations are very diverse, and include reduction in parasite load, reduced risk of predation, and increased access to food and other resources. Recent theoretical and experimental studies reveal the prevalence of such interactions among terrestrial vertebrates, and also confirm their importance within communities thought previously to be dominated by interspecific competition.     

Use of a Novel Probiotic Formulation to Alleviate Lactose Intolerance Symptoms—a Pilot Study

Probiotics and Antimicrobial Proteins - Lactose intolerance is a common condition caused by lactase deficiency and may result in symptoms of lactose malabsorption (bloating, flatulence, abdominal...     

Recording fox baiting effort across the landscape using geographic information systems: Facilitating more effective management

Predation on native vertebrates and livestock by the European Red Fox (Vulpes vulpes) remains a significant problem in many parts of Australia. Coordinated approaches to fox control are most effective in protecting these assets and involve placement of baits across the landscape by private and public land managers. However, participation in such programmes varies seasonally and the spatial coverage of baiting is often difficult to determine. Here, we describe a geographic information systems‐based system that assists land managers to collect and use spatial information, minimizing gaps in bait coverage and maximizing bait encounters by foxes to increase the effectiveness of pest control. The coordination of data collection and reporting between land managers should facilitate more effective adaptive management by allowing better strategic planning and increasing landholder involvement, which should, in turn, improve the programme's efficacy, provided other critical conditions and resources are met.