Nitrogen relations of natural and disturbed plant communities in tropical Australia

Nitrogen relations of natural and disturbed tropical plant communities in northern Australia (Kakadu National Park) were studied. Plant and soil N characteristics suggested that differences in N source utilisation occur at community and species level. Leaf and xylem sap N concentrations of plants in different communities were correlated with the availability of inorganic soil N (NH4+ and NO3-). In general, rates of leaf NO3- assimilation were low. Even in communities with a higher N status, including deciduous monsoon forest, disturbed wetland, and a revegetated mine waste rock dump, levels of leaf nitrate reductase, xylem and leaf NO3 levels were considerably lower than those that have been reported for eutrophic communities. Although NO3- assimilation in escarpment and eucalypt woodlands, and wetland, was generally low, within these communities there was a suite of species that exhibited a greater capacity for NO3- assimilation. These high-NO3- species were mainly annuals, resprouting herbs or deciduous trees that had leaves with high N contents. Ficus, a high-NO3- species, was associated with soil exhibiting higher rates of net mineralisation and net nitrification. Low-NO3- species were evergreen perennials with low leaf N concentrations. A third group of plants, which assimilated NO3- (albeit at lower rates than the high-NO3- species), and had high-N leaves, were leguminous species. Acacia species, common in woodlands, had the highest leaf N contents of all woody species. Acacia species appeared to have the greatest potential to utilise the entire spectrum of available N sources. This versatility in N source utilisation may be important in relation to their high tissue N status and comparatively short life cycle. Differences in N utilisation are discussed in the context of species life strategies and mycorrhizal associations.

Determining forest structural attributes using an inverted geometric-optical model in mixed eucalypt forests, Southeast Queensland, Australia

The Montreal Process indicators are intended to provide a common framework for assessing and reviewing progress toward sustainable forest management. The potential of a combined geometrical-optical/spectral mixture analysis model was assessed for mapping the Montreal Process age class and successional age indicators at a regional scale using Landsat Thematic data. The project location is an area of eucalyptus forest in Emu Creek State Forest, Southeast Queensland, Australia. A quantitative model relating the spectral reflectance of a forest to the illumination geometry, slope, and aspect of the terrain surface and the size, shape, and density, and canopy size. Inversion of this model necessitated the use of spectral mixture analysis to recover subpixel information on the fractional extent of ground scene elements (such as sunlit canopy, shaded canopy, sunlit background, and shaded background). Results obtained fron a sensitivity analysis allowed improved allocation of resources to maximize the predictive accuracy of the model. It was found that modeled estimates of crown cover projection, canopy size, and tree densities had significant agreement with field and air photo-interpreted estimates. However, the accuracy of the successional stage classification was limited. The results obtained highlight the potential for future integration of high and moderate spatial resolution-imaging sensors for monitoring forest structure and condition. (C) Elsevier Science Inc., 2000.

Heterogeneity in inoculum potential and effectiveness of arbuscular mycorrhizal fungi

Arbuscular mycorrhizae are symbiotic associations among glomalean fungi and plant roots that often lead to enhanced water and nutrient uptake and plant growth. We describe experiments to test whether inoculum potential of arbuscular mycorrhizal (AM) fungal communities varies spatially within a broadleaf temperate forest, and also whether there is variability in the effectiveness of AM fungal communities in enhancing seedling growth. Inoculum potential of arbuscular mycorrhizal fungi in a temperate broad-leaved forest did not vary significantly among sites. Inoculum potential, measured as the extent to which the roots of red maple seedlings that had been germinated on sterile sand and then transplanted into the forest, were colonized by AM fungi, was similar in floodplain and higher elevation sites. It was as similar under ectomycorrhizal oaks as it was under red maples and other AM tree species. It was also similar among sites with deciduous understory shrubs with arbuscular mycorrhizae (spicebush, Lindera benzoin) and those with evergreen vegetation with ericoid mycorrhizae (mountain laurel, Kalmia latifolia). Where spicebush was the dominant understory shrub, inoculum potential was greater under gaps in the canopy than within the understory. Survivorship of transplanted red maple seedlings varied significantly over sites but was not strongly correlated with measures of inoculum potential. In a greenhouse growth experiment, arbuscular mycorrhizal fungal communities obtained from tree roots from the forest had different effects on plant growth. Seedlings inoculated with roots of red maple had twice the leaf area after 10 wk of growth compared to the AM community obtained from roots of southern red oaks. Thus, although there appears to be little heterogeneity in inoculum potential in the forest, there are differences in the effectiveness of different inocula. These effects have the potential to affect tree species diversity in forests by modifying patterns of seedling recruitment.

Analytical solution for tidal propagation in a coupled semi-confined/phreatic coastal aquifer

An analytical solution is derived for tidal fluctuations in a coupled coastal aquifer system consisting of a semi-confined aquifer, a thin semi-permeable layer and a phreatic aquifer. Based on the solution, we study the interactions (via leakage) between the confined and unconfined aquifers in response to tides. The results show that, under certain conditions, leakage from the confined aquifer can affect considerably the tidal water table fluctuation in the phreatic aquifer and vice versa. Ignoring these effects could lead to errors in estimating aquifer properties based on tidal signals. (C) 2002 Elsevier Science Ltd. All rights reserved.

Scope for further analytical solutions for constant flux infiltration into a semi-infinite soil profile or redistribution in a finite soil profile

[1] We attempt to generate new solutions for the moisture content form of the one-dimensional Richards' [1931] equation using the Lisle [1992] equivalence mapping. This mapping is used as no more general set of transformations exists for mapping the one-dimensional Richards' equation into itself. Starting from a given solution, the mapping has the potential to generate an infinite number of new solutions for a series of nonlinear diffusivity and hydraulic conductivity functions. We first seek new analytical solutions satisfying Richards' equation subject to a constant flux surface boundary condition for a semi-infinite dry soil, starting with the Burgers model. The first iteration produces an existing solution, while subsequent iterations are shown to endlessly reproduce this same solution. Next, we briefly consider the problem of redistribution in a finite-length soil. In this case, Lisle's equivalence mapping is generalized to account for arbitrary initial conditions. As was the case for infiltration, however, it is found that new analytical solutions are not generated using the equivalence mapping, although existing solutions are recovered.

Ecosystem process models at multiple scales for mapping tropical forest productivity

Quantifying mass and energy exchanges within tropical forests is essential for understanding their role in the global carbon budget and how they will respond to perturbations in climate. This study reviews ecosystem process models designed to predict the growth and productivity of temperate and tropical forest ecosystems. Temperate forest models were included because of the minimal number of tropical forest models. The review provides a multiscale assessment enabling potential users to select a model suited to the scale and type of information they require in tropical forests. Process models are reviewed in relation to their input and output parameters, minimum spatial and temporal units of operation, maximum spatial extent and time period of application for each organization level of modelling. Organizational levels included leaf-tree, plot-stand, regional and ecosystem levels, with model complexity decreasing as the time-step and spatial extent of model operation increases. All ecosystem models are simplified versions of reality and are typically aspatial. Remotely sensed data sets and derived products may be used to initialize, drive and validate ecosystem process models. At the simplest level, remotely sensed data are used to delimit location, extent and changes over time of vegetation communities. At a more advanced level, remotely sensed data products have been used to estimate key structural and biophysical properties associated with ecosystem processes in tropical and temperate forests. Combining ecological models and image data enables the development of carbon accounting systems that will contribute to understanding greenhouse gas budgets at biome and global scales.

Four new species of Paratrizygia Tonnoir from the Brazilian Atlantic Forest (Diptera, Mycetophilidae, Sciophilinae)

Paratrizygia Tonnoir was originally described for P. conformis, from Australia, and since then only four species have been added to the genus, from Chile and Southern Argentina. We add four new species to the genus Paratrizygia-P. balbii sp. nov., P. alvesi sp. nov., P. camargoi sp. nov., and P. albidens sp.nov.-from the southern part of the Brazilian Atlantic Forest. Comments are made about the possible relationships of the Brazilian and other Neotropical species of the genus. An identification key to the Neotropical species of the genus is provided.

Five new species of Coniceromyia Borgmeier (Diptera: Phoridae) from the Atlantic Forest, Brazil

Five new species of Coniceromyia from the Atlantic Forest in Brazil are herein described-Coniceromyia apechoneura, sp. nov., C. brandaoi, sp. nov., C. diaphaniptera, sp. nov., C. franciscana, sp. nov., and C. sanctaetheresae, sp. nov. Both C. diaphaniptera and C. franciscana have patterned wings. The male foretibia provides important diagnostic features for the species, as well as additional characters to propose clades within the genus. The male hypopygial morphology is described.

Four new species of Paraclius Loew (Diptera: Dolichopodidae) from the Brazilian Atlantic Forest, and notes on the systematic position of Cheiromyia Dyte

Four new species of Paraclius Loew from the Brazilian Atlantic Forest are described and illustrated: P. amphiatheratus, sp. nov., P. parenti, sp. nov., P. sagittatus, sp. nov., and P. dicrophallus, sp. nov. The condition of their enlarged sperm pump, also seen in the Neotropical genus Cheiromyia Dyte, is briefly discussed. Comments on the phylogenetic position of Cheiromyia are presented in light of new data from female terminalia of that genus.

Morphological and morphometric appraisal of the spermatophore of the southern hermit crab Isocheles sawayai Forest and Saint Laurent, 1968 (Anomura: Diogenidae), with comments on gonopores in both sexes

The spermatophore morphology of the hermit crab Isocheles sawayai from Southwestern Atlantic (Brazil) is described. The spermatophores show similarities with those described for other members of the family Diogenidae, especially with the recently described Loxopagurus loxochelis. The spermatophore is composed of three major regions: a sperm filled head or ampulla, a columnar stalk and a foot or pedestal. The spermatophores show specific morphology in having a circular ampulla, and a constriction or neck between the ampulla (100 mu m) and the thin (27 mu m), long stalk (500 mu m). The stalk penetrates less than half way into the spermatophore head. Most spermatophores show one or the small posterior projections on the underside of the ampulla as being bigger than the other, making it asymmetrical. The size of the spermatophore is related to hermit crab size with direct relationships found between spermatophore ampulla width, total length, and peduncle length with shield length of the hermit crab. The morphological characteristics of the spermatophore of L sawayai. are species-specific distinguishing it from other members of the family, and are useful to infer further phylogenetic relationships. (C) 2008 Elsevier GmbH. All rights reserved.

Eleven new species of the genus Cluzobra Edwards (Diptera, Mycetophilidae, Sciophilinae) from the Atlantic Forest of Brazil

Eleven new species of the sciophiline genus Cluzobra Edwards are described and illustrated - Cluzobra triocellata, sp.n., Cluzobra accola, sp.n., Cluzobra claripennis, sp.n., Cluzobra papaveroi, sp.n., Cluzobra coptolithus, sp.n., Cluzobra vockerothi, sp.n., Cluzobra sapiranga, sp.n., Cluzobra fluminense, sp.n., Cluzobra fritzmuelleri, sp.n., Cluzobra spinata, sp.n., Cluzobra elpidia, sp.n. Additional specimens of C. fuscipennis Edwards, C. plaumanni Edwards, and C. binocellaris (Edwards) have been identified, extending the distribution range of these species. The species were identified and described based on 173 specimens at different latitudes along the Atlantic Forest in eastern Brazil and northern Argentina. The position of the new species in the groups of species proposed for the genus in the literature is considered. Three areas of endemism are identified for the group, one from southern Brazil, northern Argentina and Paraguay northwards to areas at higher altitudes in the States of Minas Gerais and Rio de Janeiro, one from southern Bahia to the extreme north of the Atlantic Forest, in the State of Rio Grande do Norte, and one in west State of Sao Paulo, extending west and northwards into the states of Mato Grosso do Sul and Goias. This paper raises the number of known Cluzobra to 41 species.

Synthesis and Characterization of Semi-Interpenetrating Networks Based on Poly(dimethylsiloxane) and Poly(vinyl alcohol)

Semi-interpenetrating networks (Semi-IPNs) with different compositions were prepared from poly(dimethylsiloxane) (PDMS), tetraethylorthosilicate (TEOS), and poly (vinyl alcohol) (PVA) by the sol-gel process in this study. The characterization of the PDMS/PVA semi-IPN was carried out using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and swelling measurements. The presence of PVA domains dispersed in the PDMS network disrupted the network and allowed PDMS to crystallize, as observed by the crystallization and melting peaks in the DSC analyses. Because of the presence of hydrophilic (-OH) and hydrophobic (Si-(CH(3))(2)) domains, there was an appropriate hydrophylic/hydrophobic balance in the semi-IPNs prepared, which led to a maximum equilibrium water content of similar to 14 wt % without a loss in the ability to swell less polar solvents. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 158-166, 2010

The influence of oscillations on global existence for a class of semi-linear wave equations

The goal of this paper is to study the global existence of small data solutions to the Cauchy problem for the nonlinear wave equation u(tt) - a(t)(2) Delta u = u(t)(2) - a(t)(2)vertical bar del u vertical bar(2). In particular we are interested in statements for the 1D case. We will explain how the interplay between the increasing and oscillating behavior of the coefficient will influence global existence of small data solutions. Copyright c 2011 John Wiley & Sons, Ltd.

Choice of macroinvertebrate metrics to evaluate stream conditions in Atlantic Forest, Brazil

The development of biomonitoring programs based on the macroinvertebrate community requires the understanding of species distribution patterns, as well as of the responses of the community to anthropogenic stressors. In this study, 49 metrics were tested as potential means of assessing the condition of 29 first- and second-order streams located in areas of differing types of land use in So Paulo State, Brazil. Of the sampled streams, 15 were in well-preserved regions in the Atlantic Forest, 5 were among sugarcane cultivations, 5 were in areas of pasture, and 4 were among eucalyptus plantations. The metrics were assessed against the following criteria: (1) predictable response to the impact of human activity; (2) highest taxonomic resolution, and (3) operational and theoretical simplicity. We found that 18 metrics were correlated with the environmental and spatial predictors used, and seven of these satisfied the selection criteria and are thus candidates for inclusion in a multimetric system to assess low-order streams in So Paulo State. These metrics are family richness; Ephemeroptera, Plecoptera and Trichoptera (EPT) richness; proportion of Megaloptera and Hirudinea; proportion of EPT; Shannon diversity index for genus; and adapted Biological Monitoring Work Party biotic index.