The loss of an indigenous constructed landscape following British invasion of Australia: An insight into the deep human imprint on the Australian landscape

Indigenous people play an integral role in shaping natural environments, and the disruption to Indigenous land management practices has profound effects on the biosphere. Here, we use pollen, charcoal and dendrochronological analyses to demonstrate that the Australian landscape at the time of British invasion in the 18th century was a heavily constructed one—the product of millennia of active maintenance by Aboriginal Australians. Focusing on the Surrey Hills, Tasmania, our results reveal how the removal of Indigenous burning regimes following British invasion instigated a process of ecological succession and the encroachment of cool temperate rainforest (i.e. later-stage vegetation communities) into grasslands of conservation significance. This research provides empirical evidence to challenge the long-standing portrayal of Indigenous Australians as low-impact ‘hunter-gatherers’ and highlights the relevance and critical value of Indigenous fire management in this era of heightened bushfire risk and biodiversity loss.     

Factors Affecting Take-up of and Drop-out from Home Composting Schemes

This paper reports survey results from Scotland and north-west England into home composting attitudes and behaviours. The results concentrate on: the take-up of home composting through promotional campaigns; and the reasons for drop-out. Motivations for take-up were balanced between environmental and gardening reasons, although capital cost was an important issue for some. Drop-outs occurred mainly through participants moving house or because of lack of success in producing compost. Few of those experiencing problems sought help. Those that did favoured official or professional sources. Neighbourhood social pressures to compost were relatively weak. The results are discussed in terms of the sustainability of home composting behaviour and the manage ment interventions that might be required in sustaining that behaviour.     

A Review of Personal/Portable Monitors and Samplers for Airborne Particles

A review of personal and portable particulate monitors and samplers for measuring and sampling airborne particulate matter is presented. These monitors and samplers are proving to be valuable tools for assessing individual exposure to environmental and occupationally generated particulates. The devices are characterized in terms of their sampling characteristics, their monitoring or measurement technique, their particle size separation (50% cut point) capabilities, their sampling flow rate, and their sampling duration per one battery charging cycle. All of the monitors and some of the samplers are commercially available. Commercial sources and originators (in the case of research devices) are made available.     

The interactive relationship of competitive climate and trait competitiveness with workplace attitudes,stress, and performance

There has been a considerable debate about the individual and organizational benefits of competition. Adopting a person–environment fit perspective, this research examined the influence of competition as an interaction between trait competitiveness and competitive climate. Using a sample of information technology workers, competitive climate was considered as both an individual level variable and a workgroup variable. Results show that the effect of competitive climate depended on trait competitiveness and the level at which climate was assessed for four of the outcomes assessed: job satisfaction, organizational commitment, job dedication, and supervisor‐rated task performance. In general, the effect of competitive climate was more negative for individuals lower in trait competitiveness. Competitive psychological climate was associated with greater stress regardless of the level of trait competitiveness but was not directly related to self‐rated task performance. Findings suggest that managers should be cautious in encouraging competitive climate. Copyright © 2007 John Wiley & Sons, Ltd.     

Patterns of courtship behavior and ejaculate characteristics in male red-winged blackbirds

Sperm competition in birds is likely to have important effects on the behavior and physiology of reproduction in both sexes. For males, such competition should select for large sperm reserves and behavioral adjustment of copulation when reserves are low. We investigated both these possibilities in free-living red-winged blackbirds (Agelaius phoeniceus), a highly polygynous species with apparently strong sperm competition. We found that the recent copulatory behavior of males did not affect the propensity to copulate with a model female. Ejaculates collected from individual males at 1-h intervals showed no evidence of sperm depletion, yet repeated ejaculates collected less than 10 min apart did. Male ejaculate size was significantly larger if it was the first one of the day (i.e., after an overnight rest). The average ejaculate size was 12.5 (±12.5 SD) million sperm. Males captured during the breeding season had an average of 111.7 (±52.8) million sperm stored in their seminal glomera. Because males average a peak copulation rate of six per female per day, in one day a male might utilize all the sperm in his seminal glomera if more than two females on his territory are fertilizable. We hypothesize that polygyny and sperm competition in this species have combined to select for rapid replenishment of the seminal glomera throughout the day, in contrast to other species that have been studied. Testis size and sperm reserves of male red-winged blackbirds are intermediate between monogamous species and species with intense sperm competition. Several possible explanations for this are discussed. Received: 21 October 1997 / Accepted after revision: 15 February 1998     

The functional response of a hoarding seed predator to mast seeding

Mast seeding involves the episodic and synchronous production of large seed crops by perennial plants. The predator satiation hypothesis proposes that mast seeding maximizes seed escape because seed predators consume a decreasing proportion of available seeds with increasing seed production. However, the seed escape benefits of masting depend not only on whether predators are satiated at high levels of seed production, but also on the shape of their functional response (type II vs. type III), and the actual proportion of available seeds that they consume at different levels of seed production. North American red squirrels (Tamiasciurus hudsonicus) are the primary vertebrate predator of white spruce (Picea glauca) mast seed crops in many boreal regions because they hoard unopened cones in underground locations, preempting the normal sequence of cone opening, seed dispersal, and seed germination. We document the functional response of cone-hoarding by red squirrels across three non-mast years and one mast year by estimating the number of cones present in the territories of individual red squirrels and the proportion of these cones that they hoarded each autumn. Even though red squirrels are not constrained by the ingestive and on-body (fat reserves) energy reserve limitations experienced by animals that consume seeds directly, most squirrels hoarded < 10% of the cones present on their territories under mast conditions. Cone availability during non-mast years also reached levels that satiated the hoarding activity of red squirrels; however, this occurred only on the highest-quality territories. Squirrels switched to mushroom-hoarding when cone production was low and mushrooms were abundant. This resulted in type III functional response whereby the proportional harvest of cones was highest at levels of cone availability that were intermediate within non-mast years. Overall, more cones escaped squirrel cone-hoarding during a mast event than when cone production was low in non-mast years, which supports the predator satiation hypothesis. However, the highly variable seed escape in non-mast years may help to explain why all spruce cone production is not concentrated into fewer, larger, mast years.     

The use of benthic mesocosms for the assessment of sediment contamination.

The diagnostic capability of changes in the benthic macroinvertebrate community composition to determine the cause in contaminated sediments were addressed using box core mesocosms subjected to cadmium, atrazine and nutrient enrichment. Intact cores of lake sediment were collected from Lake Erie at four occasions during 1996 and were returned to laboratory where they were maintained and manipulated. The benthic community composition of the artificially polluted mesocosms was compared with field data, collected at the same time as the intact cores, and to untreated control boxes. Community composition was related to the measured environmental variables using multi-dimensional scaling (MDS) and principle axis correlation (PCC). Community responses to different treatments were both different and consistent, suggesting that the community structure of these mesocosms could be used to identify the primary source of impact.     

Ecological recovery of vegetation at a former industrial sludge basin and its implications to phytoremediation

Examination of a former industrial sludge basin containing organic pollutants showed that the basin had undergone substantial ecological recovery through natural forces following the removal of surface water in 1982. Conventional phases of ecological recovery (plant invasion and succession) have occurred, but the structure of the biodiverse plant community (51 species and 22 families) was different from that at a recovering non-polluted disturbed site. Three plant species (Bermuda grass, mulberry, and sunflower) believed to be early invaders of the basin still persist in large numbers indicating that these species are well suited to cope with normal environmental stresses at this area (i.e. seasonal drought and flood) as well as organic pollutants. There was an indication that early invaders of the site fostered disappearance of contaminants thereby creating more favorable conditions for a broader spectrum of plants to grow. Vegetation analyses of naturally vegetated hazardous waste sites hold promise as a screening device for identifying plant species and management practices worthy of further phytoremediation investigations.     

Development of a personal exposure monitor for two sizes of inhalable particulates

Measurement of personal exposure to ambient level particulate concentrations is often extremely difficult because of a lack of personal exposure monitors capable of collecting measurable quantities within a meaningful sampling period. A new personal exposure monitor for two fractions of inhalable particulates (i.e., the 3–15 μm aerodynamic diameter and the < 3 μm or respirable fraction) has been developed and characterized. This monitor is capable of collecting a sample of each fraction that is quantifiable with ambient concentrations of inhalable/respirable particulates as low as 25 μg/m³ in a 24-h sampling period. Wind tunnel tests have been made on the particulate personal exposure monitor to determine sampling efficiency as a function of relative wind speed and orientation with respect to the sampler.