Αξιολόγηση εξωτερικοτήτων εγκαταστάσεων βιοαερίου

Fusarium oxysporum f. sp. cubense tropical race 4 (TR4) is reported for the first time in northern Queensland, the centre of Australia’s commercial banana production. The identity of the pathogen was confirmed by vegetative compatibility group testing, TR4 specific PCR tests and sequencing. Although presently confined to a single property, the disease poses a serious threat to Australia’s banana industry

The “edge effect” phenomenon: deriving population abundance patterns from individual animal movement decisions

Edge effects have been observed in a vast spectrum of animal populations. They occur where two conjoining habitats interact to create ecological phenomena that are not present in either habitat separately. On the individual-level, an edge effect is a change in behavioral tendency on or near the edge. On the population-level, it is a pattern of population abundance near an edge that cannot be explained in terms of either habitat in isolation. That these two levels of description exist suggests there ought to be a mathematical link between them. Here, we make inroads into providing such a link, deriving analytic expressions describing oft-observed population abundance patterns from a model of movement decisions near edges. Depending on the model parameters, we can see positive, negative, or transitional edge effects emerge. Importantly, the distance over which animals make their decisions to move between habitats turns out to be a key factor in quantifying the magnitude of certain observed edge effects

ASPECTS OF RAINFOREST REGENERATION: III. THE INTERACTION OF PHENOLS, LIGHT AND NUTRIENTS

Measurements in two sub‐tropical rainforests demonstrated that (i) in one rainforest succession, total soil phenols varied dramatically throughout the study year with soils from the ‘climax’ rainforest exhibiting highest phenol levels, the nature of these phenolic compounds was not investigated; (ii) in the other rainforest succession, the 55‐year‐old regrowth exhibited highest total phenols, but the level of condensed tannins increased throughout the succession. The highest level of nitrification was observed in soils containing highest total phenols but the addition of ferulic acid decreased nitrification. Studies on Argyrodendron trifoliolatum demonstrated that addition of the phenol, caffeic acid, to nutrient media enhanced leaf concentrations of Zn, Mn and P. Increasing light intensities, however, decreased foliar concentrations of Fe, Zn, Mn and P but had no effect on Ca or N. Plants raised on ammonium −N exhibited higher levels of Fe, Zn, Mn and P than those raised on nitrate–N. Glasshouse trials showed that at low light intensities omission of N, P and N + P did not dramatically enhance leaf phenol production. Almost invariably, an increase in light intensity increased leaf phenols but only one of the four species examined (Syzygium floribundum) exhibited marked responses to nutrient deficiencies at high light intensities, with the omission of nitrogen leading to highest leaf phenols. Copyrigh

Population ecology of the southern cassowary Casuarius casuarius johnsonii, Mission Beach north Queensland

Little is known of the ecology and population dynamics of the world’s largest avian frugivore. This study investigated the population of endangered southern cassowary at Mission Beach, northeast Australia, and examined the problems associated with determining population size and density of this keystone species. Using the results of an intensive field survey aimed at estimating absolute numbers of individual cassowaries, the appropriate sampling methodology for rare and elusive species was explored. Approximately 102 km2 of rainforest was surveyed using 346 km of search transects. Of a total of 110 cassowaries, there were 49 adults (28 male, 19 female, 2 unknown), 28 subadults, 31 chicks, and 2 independent birds of unknown status. This is approximately 35% of the adult population previously estimated for the Mission Beach area. Overall adult cassowary density was 0.48 adults/km2; the density of independent birds, i.e. adults and subadults, was 0.78 birds/km2. Mean indicative home range (IHR) for adult females and males was 2.13 and 2.06 km2, respectively. Mean IHR of subadults was smaller at 0.95 km2. It was concluded that the previous practice of surveying small areas at Mission Beach (<4 km2) has led to consistent overestimation of cassowary population density, up to six times its real number. It is shown that a sample plot between 5 and 15 km2 is necessary to approximate true cassowary density. These findings have significant application to the conservation of cassowaries in New Guinea and in the Wet Tropics World Heritage Area of Australia