Effects of an invasive species on refuge-site selection by native fauna : the impact of cane toads on native frogs in the Australian tropics

Invasive species can induce shifts in habitat use by native taxa: either by modifying habitat availability, or by repelling or attracting native species to the vicinity of the invader. The ongoing invasion of cane toads (Rhinella marina) through tropical Australia might affect native frogs by affecting refuge-site availability, because both frogs and toads frequently shelter by day in burrows. Our laboratory and field studies in the wet-dry tropics show that native frogs of at least three species (Litoria tornieri, Litoria nasuta and Litoria dahlii) preferentially aggregate with conspecifics, and with (some) other species of native frogs. However, the frogs rarely aggregated with cane toads either in outdoor arenas or in standardized experimental burrows that we monitored in the field. The native frogs that we tested either avoided burrows containing cane toads (or cane toad scent) or else ignored the stimulus (i.e. treated such a burrow in the same way as they did an empty burrow). Native frogs selected a highly non-random suite of burrows as diurnal retreat sites, whereas cane toads were less selective. Hence, even in the absence of toads, frogs do not use many of the burrows that are suitable for toads. The invasion of cane toads through tropical Australia is unlikely to have had a major impact on retreat-site availability for native frogs.

Contribution of fungi to primary biogenic aerosols in the atmosphere: wet and dry discharged spores, carbohydrates, and inorganic ions

Biogenic aerosols play important roles in atmospheric chemistry physics, the biosphere, climate, and public health. Here, we show that fungi which actively discharge their spores with liquids into the air, in particular actively wet spore discharging Ascomycota (AAM) and actively wet spore discharging Basidiomycota (ABM), are a major source of primary biogenic aerosol particles and components. We present the first estimates for the global average emission rates of fungal spores.

Measurement results and budget calculations based on investigations in Amazonia (Balbina, Brazil, July 2001) indicate that the spores of AAM and ABM may account for a large proportion of coarse particulate matter in tropical rainforest regions during the wet season (0.7–2.3 μg m⁻³). For the particle diameter range of 1–10 μm, the estimated proportions are ~25% during day-time, ~45% at night, and ~35% on average. For the sugar alcohol mannitol, the budget calculations indicate that it is suitable for use as a molecular tracer for actively wet discharged basidiospores (ABS). ABM emissions seem to account for most of the atmospheric abundance of mannitol (10–68 ng m⁻³), and can explain the observed diurnal cycle (higher abundance at night). ABM emissions of hexose carbohydrates might also account for a significant proportion of glucose and fructose in air particulate matter (7–49 ng m⁻³), but the literature-derived ratios are not consistent with the observed diurnal cycle (lower abundance at night). AAM emissions appear to account for a large proportion of potassium in air particulate matter over tropical rainforest regions during the wet season (17–43 ng m⁻³), and they can also explain the observed diurnal cycle (higher abundance at night). The results of our investigations and budget calculations for tropical rainforest aerosols are consistent with measurements performed at other locations.

Based on the average abundance of mannitol reported for extratropical continental boundary layer air (~25 ng m⁻³), we have also calculated a value of ~17 Tg yr⁻¹ as a first estimate for the global average emission rate of ABS over land surfaces, which is consistent with the typically observed concentrations of ABS (~10³–10⁴ m⁻³; ~0.1^–1 μg m⁻³). The global average atmospheric abundance and emission rate of total fungal spores, including wet and dry discharged species, are estimated to be higher by a factor of about three, i.e. 1 μg m⁻³ and ~50 Tg yr⁻¹. Comparisons with estimated rates of emission and formation of other major types of organic aerosol (~47 Tg yr⁻¹ of anthropogenic primary organic aerosol; 12–70 Tg yr⁻¹ of secondary organic aerosol) indicate that emissions from fungi should be taken into account as a significant global source of organic aerosol. The effects of fungal spores and related chemical components might be particularly important in tropical regions, where both physicochemical processes in the atmosphere and biological activity at the Earth's surface are particularly intense, and where the abundance of fungal spores and related chemical compounds are typically higher than in extratropical regions.

Latitudinal gradients in abundance, and the causes of rarity in the tropics: a test using Australian honeyeaters (Aves: Meliphagidae)

Several studies have uncovered interspecific latitudinal gradients in abundance (population density) such that tropical species tend to be, on average, less abundant than species at higher latitudes. The causes of this relationship remain poorly studied, in contrast to the relative wealth of literature examining the relationship to latitude of other variables such as range size and body mass. We used a cross-species phylogenetic comparative approach and a spatial approach to examine three potential determining factors (distribution, reproductive output and climate) that might explain why abundance correlates with latitude, using data from 54 species of honeyeaters (Meliphagidae) in woodland environments in eastern Australia. There is a strong positive correlation between mean abundance and latitude in these birds. Reproductive output (clutch size) was positively linked to both abundance and latitude, but partial correlation analysis revealed that clutch size is not related to abundance once the effects of latitude are removed. A subsequent multiple regression model that also considered range size, clutch size and body mass showed that latitude is the only strong predictor of abundance in honeyeaters. In the separate spatial analysis, the climatic variables that we considered (temperature, rainfall and seasonality) were all strongly linked to latitude, but none served as a better predictor of abundance than latitude per se, either individually or collectively. The most intriguing result of our analyses was that the cross-species latitudinal pattern in abundance was not evident within species. This suggests an intrinsic cause of the pattern of ‘rarity in the tropics’ in Australian honeyeaters. We suggest that evolutionary age may provide a key to understanding patterns of abundance in these birds.

Large-herbivore distribution and abundance : intra-and interspecific niche variation in the tropics

Determining the biological and environmental factors that limit the distribution and abundance of organisms is central to our understanding of the niche concept and crucial for predicting how species may respond to large-scale environmental change, such as global warming. However, detailed ecological information for the majority of species has been collected only at a local scale, and insufficient consideration has been given to geographical variation in intraspecific niche requirements. To evaluate the influence of environmental and biological factors on patterns of species distribution and abundance, we conducted a detailed, broadscale study across the tropical savannas of northern Australia on the ecology of three large, sympatric marsupial herbivores (family Macropodidae): the antilopine wallaroo (Macropus antilopinus), common wallaroo (M. robustus), and eastern grey kangaroo (M. giganteus). Using information on species abundance, climate, fire history, habitat, and resource availability, we constructed species' habitat models varying from the level of the complete distribution to smaller regional areas. Multiple factors affected macropod abundance, and the importance of these factors was dependent on the spatial scale of analyses. Fire regimes, water availability, geology, and soil type and climate were most important at the large scale, whereas aspects of habitat structure and interspecific species abundance were important at smaller scales. The distribution and abundance of eastern grey kangaroos and common wallaroos were strongly influenced by climate. Our results suggest that interspecific competition between antilopine wallaroos and eastern grey kangaroos may occur. The antilopine wallaroo and eastern grey kangaroo (grazers) preferred more nutrient-rich soils than the common wallaroo (grazer/browser), which we relate to differences in feeding modes. The abundance of antilopine wallaroos was higher on sites that were burned, whereas the abundance of common wallaroos was higher on unburned sites. Future climate change predicted for Australia has the capacity to seriously affect the abundance and conservation of macropod species in tropical savannas. The results of our models suggest that, in particular, the effects of changing climatic conditions on fire regimes, habitat structure, and water availability may lead to species declines and marked changes in macropod communities.

The impact of textile wet colouration on the environment in 2011

Wet textile colouration has the highest environmental impact of all textile processing steps. It consumes water, chemicals and energy and produces liquid, heat and gas waste streams. Liquid effluent streams are often quite toxic to the environment. There are a number of different dyeing processes, normally fibre type specific, and each has a different impact on the environment. This research investigated the energy, chemical and water requirements for the exhaust colouration of cotton, wool, polyester and nylon. The research investigated the liquid waste biological and chemical oxygen demand, salinity, pH and colour along with the energy required for drying after colouration. Polyester fibres had the lowest impact on the environment with lowest water and energy consumption in dyeing, good dye bath exhaustion, the lowest salinity levels in their effluent, relatively neutral pH effluent and low energy in drying. The wool and nylon had similar dye bath requirements and outputs however the nylon could be dyed at far lower liquor ratios and hence provided better energy and water use figures. The cotton and wool required high energy consumption in drying after colouration. Cotton performed poorly in all of the measured parameters.

Astrology pack SPOKEN WORD bright and wet

This is an astrology pack of spoken words speaking the full range of zodiac signs. It is designed for those carrying out astrological readings. This pack is a female voice (English accent) and it is bright and wet (effects).

Astrology pack SPOKEN WORD wet

This is an astrology pack of spoken words speaking the full range of zodiac signs. It is designed for those carrying out astrological readings. This pack is a female voice (English accent) and it is wet.

The impact of textile wet colouration on the environment in 2011

Wet textile colouration has the highest environmental impact of all textile processing steps. It consumes water, chemicals and energy and produces liquid, heat and gas waste streams. Liquid effluent streams are often quite toxic to the environment. There are a number of different dyeing processes, normally fibre type specific, and each has a different impact on the environment. This research investigated the energy, chemical and water requirements for the exhaust colouration of cotton, wool, polyester and nylon. The research investigated the liquid waste biological oxygen demand, total organic carbon dissolved solids, suspended solids, pH and colour along with the energy required for drying after colouration. Polyester fibres had the lowest impact on the environment with low water and energy consumption in dyeing, good dye bath exhaustion, the lowest dissolved solids levels in waste water, relatively neutral pH effluent and low energy in drying. The wool and nylon had similar dyebath requirements and outputs however the nylon could be dyed at far lower liquor ratios and hence provided better energy and water use figures. Cotton performed badly in all of the measured parameters.

Toad's tongue for breakfast : exploitation of a novel prey type, the invasive cane toad, by scavenging raptors in tropical Australia

Although interest in the ecological impacts of invasive species has largely focused on negative effects, some native taxa may benefit from invader arrival. In tropical Australia, invasive cane toads (Bufo marinus) have fatally poisoned many native predators (e.g., marsupials, crocodiles, lizards) that attempt to ingest the toxic anurans, but birds appear to be more resistant to toad toxins. We quantified offtake of dead (road-killed) cane toads by raptors (black kites (Milvus migrans) and whistling kites (Haliastur sphenurus)) at a site near Darwin, in the Australian wet-dry tropics. Raptors readily took dead toads, especially small ones, although native frogs were preferred to toads if available. More carcasses were removed in the dry season than the wet season, perhaps reflecting seasonal availability of alternative prey. Raptors appeared to recognize and avoid bufotoxins, and typically removed and consumed only the toads’ tongues (thereby minimizing toxin uptake). The invasion of cane toads thus constitutes a novel prey type for scavenging raptors, rather than (as is the case for many other native predators) a threat to population viability.