A model of litter harvesting by the Western Australian wheatbelt termite,Drepanotermes tamminensis (Hill), with particular reference to nutrient dynamics

A series of papers have been published which describe the influence of vegetation and soil type on the Western Australian wheatbelt termite,Drepanotermes tamminensis (Hill), and also on its litter harvesting levels and contribution to the soil nutrient budget. This paper integrates these findings by means of a computer simulation model. The model consists of three modules which respectively describe the dynamics of litter on the ground, the dynamics of litter within termite mounds and how these in turn influence nutrient loads within the habitat. The outputs of the model suggest that this litter harvesting termite plays an important role in the nutrient dynamics of the area and it provides an estimate of the unmeasured variable, litter consumed in mounds by termites, which is consistent with measurements for other termite species with similar feeding habits.     

Conserved nonplanar heme distortions in cytochromesc

A nonplanar distortion of the heme ofc-type cytochromes is conserved in the proteins isolated from diverse species based upon a comprehensive analysis of available highresolution X-ray crystal structures. This distortion is induced through the cysteine thioether linkages between the porphyrin pyrrole groups and the polypeptide and results in an asymmetric pyrrole distortion. This asymmetry in the heme distortion is also conserved. For other heme proteins which lack these covalent bonds, nearly planar porphyrins are observed. Resonance Raman evidence indicates that nonplanar distortion of porphyrins containing metals, like iron, with large core sizes (?2.00 Å) is energetically unfavorable and can occur only in the presence of significant environmental perturbations. Further, energy minimization and dynamics calculations on the ferric form of yeast iso-1-cytochromec, starting from the crystallographic coordinates and using a molecular mechanics force field which accurately reproduces nonplanar distortions in metalloporphyrins, suggest that this distortion is indeed maintained by the protein tertiary structure. It is proposed that this protein-linked heme distortion modulates electron transfer function through modification of redox potentials of the porphyrin ring and the protein binding properties ofc-type cytochromes.     

Restoration Ecology's silver jubilee: innovation,debate, and creating a future for restoration ecology

At a time when the science and practice of restoration ecology is adapting to ongoing environmental and social change, innovations in both methods and concepts are essential. Encouraging innovation means allowing open debate about alternative approaches that may add to the toolbox available for restoration. Such approaches are usually being examined as additions to, rather than substitutes for, traditional restoration practices. Recent debate has focused on the scope and intent of restoration as defined in documents such as the Society for Ecological Restoration Standards. There is a mismatch between the default aim in the standards of full restoration to a native reference system and the goals of international restoration efforts that have a broader and more functional focus. The next generation of restoration scientists and practitioners will need to navigate these issues to ensure that restoration remains effective and relevant. This will require, amongst other things, ongoing learning, sharing information and insights, humility, objectivity, continuous examination of assumptions, and questioning current practices and perspectives.     

VEGETATIVE REGROWTH FOLLOWING CUTTING IN THE SHRUB BACCHARIS PILULARIS SSP. CONSANGUINEA (DC) C. B. WOLF

The resprouting ability following cutting of the chaparral shrub Baccharis pilularis ssp. consanguinea (DC) C. B. Wolf was investigated following the felling of individuals of various ages. Numbers of resprouts and resprout biomass were low in 1-yr-old shrubs, increased to a maximum in shrubs 3–4 yr old, and declined to zero in shrubs <8 yr old. Numbers of leaves produced were also lower in 1-yr-old shrubs. The results are interpreted on the basis of the internal origin of resprout buds and the increasing extent of the shrub's root system as it matures.     

Assessing nursery habitat quality for native smelts (Osmeridae) in the low-salinity zone of the San Francisco estuary

Habitat quality was assessed for two native osmerids, delta smelt Hypomesus transpacificus and longfin smelt Spirinchus thaleichthys , between two distinct nursery areas located in the low-salinity zone of the San Francisco estuary. The relationship between several variables was investigated including fish density, fish size, feeding success and the general condition of larvae as well as juveniles for both species. The nursery habitats that were evaluated included the North and South Channels of Suisun Bay. The results showed higher densities of zooplankton and decreased water velocities for the North Channel when compared to the South Channel. The dominant prey item was calanoid copepod Pseudodiaptomus forbesi for both species although longfin smelt residing in the North Channel also included another copepod in their diets, Acanthocyclops spp. In both locations, delta smelt fed predominantly during daytime flood tides, while longfin smelt feeding appeared to continue into the night hours. When both locations were compared, delta smelt in the North Channel exhibited higher densities, larger sizes, increased somatic condition and larvae <15 mm standard length demonstrated greater feeding success. Longfin smelt, exhibited similar densities, feeding success and size distributions between both channels, but generally showed poorer somatic condition for the South Channel, potentially due to energetic costs associated with documented vertical migration behaviour. Overall, the physical conditions of the North Channel provided superior habitat for both species, while the South Channel afforded only marginal habitat for longfin smelt and very poor habitat for delta smelt. Therefore, the North Channel of Suisun Bay acts as critical nursery habitat by providing better feeding and growing conditions leading to increased health and survival for both species.