In vitro and immunological assessment of the estrogenic activity and concentrations of 17β-estradiol, estrone, and ethinyl estradiol in treated effluent from 45 wastewater treatment plants in Victoria, Australia

The project was conducted between May 2006 and September 2007, and involved the collection of effluent samples from 45 wastewater treatment plants (WWTPs). The 45 WWTPs included 16 lagoon-based plants and 29 with activated sludge-based processes. Permission was obtained from all the relevant water authorities to collect samples of final effluent at point of discharge to the environment, whether that was to a creek, a river, the ocean, or the land. Samples were collected on two occasions, namely, in August 2006 (winter) and late February–early March 2007 (summer), and subjected to a number of biological and chemical analyses, including toxicity tests, measurement of hormonal (estrogenic) activity using yeast-based bioassays, and measurement of specific hormonal concentrations using enzyme-linked immunosorbent assays (ELISAs). Almost all of the effluents examined showed estrogenic activity: in winter, no activity to 73 ng/l 17β-estradiol equivalents (EEQ); and in summer, no activity to 20 ng/l EEQ. On the whole, the levels of estrogenic activity observed were comparable with the range recently reported in Australia and New Zealand using human estrogen receptor-based assays (“not detected” to ~10 ng/l EEQ). The low/no bioassay response was confirmed by the chemical assessment of estradiol, estrone, and ethinyl estradiol concentrations by ELISA, which returned concentrations of these compounds for the most part below 10 ng/l.

Androgenic activity of effluent from forty-five municipal waste water treatment plants in Victoria, Australia

It is well known that waste water treatment plant (WWTP) effluents are estrogenic. There has been much less consideration of the androgenic activity of WWTP effluents. To partly address the shortage of information on androgens in Australian WWTP effluents, in August 2006, and again in 2007, we collected discharges from up to 45 Victorian WWTPs (~25% of all WWTPs in Victoria), grouped by treatment process, i.e. activated sludge, extended aeration, and lagoon based treatment, and measured the total estrogenic, androgenic, retinoic acid, and aromatic hydrocarbon hydrogenase activity of the effluents using a hybrid yeast bioassay. This paper will concentrate on the androgenic activity and male hormone concentrations.

High individual repeatability and population differentiation in stable isotope ratios in winter-grown collared flycatcher Ficedula albicollis feathers

For migrants, we often lack complete information of their spatial distribution year round. Here, we used stable carbon, nitrogen and hydrogen isotope ratios extracted from feathers grown at the wintering sites of the long-distance migratory collared flycatcher Ficedula albicollis, to study how individuals from different breeding populations are distributed at the wintering sites. A sub-sample of birds was also sampled in two consecutive years to test for the repeatability of isotope ratios. Birds from the same breeding populations had more similar isotope ratios compared to birds from other nearby populations (10–100 km apart). Furthermore, isotope repeatability within individuals was high, implying that the observed pattern of isotope variation is consistent between years. We put forward two hypotheses for these patterns; 1) strong wintering site philopatry and migratory connectivity, suggesting that migratory connectivity may potentially be found on a much smaller spatial scale than previously considered, and 2) consistent interpopulation differentiation of feeding ecology at their wintering site.

Invasive plants – Do they devastate or diversify rural livelihoods? Rural farmers' perception of three invasive plants in Nepal

In this paper, we examine how rural people in the buffer zone of Chitwan National Park in Nepal perceive the effects of accidently transported invasive plant species, such as Mikania micrantha, Lantana camara and Chromolaena odorata, on their livelihoods. We found that their perception of the impact of each species on their livelihood varies with factors such as the duration of the presence of invasive plants in the landscape, and household characteristics. Results of a household survey indicate that farm households close to the forests have responded to the invasive species both as a victim and a beneficiary. Farm households are likely to adapt to the invaded environment as they have a history of interacting with invasive plants and can commoditise them through appropriate intervention. Additionally, the findings indicate that rural people are willing to invest in the control and management of invasive plants if appropriate technical assistance is available. Without assistance, they consider mitigating the infestation an unattainable mission and consider acceptance of the invasive species as a part of the rural ecosystem an inevitable outcome.

Estimating the benefits of managing invasive plants in subsistence communities

This thesis addresses the issue of estimating the willingness of members of low-income communities to contribute to the management of the invasion of exotic plant species by applying the stated preference method of a choice experiment in the buffer zone of Chitwan National Park in Nepal.

Biotic effects of climate change in urban environments: The case of the grey-headed flying-fox (Pteropus poliocephalus) in Melbourne, Australia

Urban climates are known to differ from those of the surrounding rural areas, as human activities in cities lead to changes in temperature, humidity and wind regimes. These changes can in turn affect the geographic distribution of species, the behaviour of animals and the phenology of plants. The grey-headed flying-fox (Pteropus poliocephalus) is a large, nomadic bat from eastern Australia that roosts in large colonies known as camps. Historically a warm temperate to tropical species, P. poliocephalus recently established a year-round camp in the Royal Botanic Gardens Melbourne. Using a bioclimatic analysis, we demonstrated that on the basis of long-term data, Melbourne does not fall within the climatic range of other P. poliocephalus camp sites in Australia. Melbourne is drier than other summer camps, and cooler and drier than other winter camps. The city also receives less radiation, in winter and annually, than the other summer and winter camps of P. poliocephalus. However, we found that temperatures in central Melbourne have been increasing since the 1950s, leading to warmer conditions and a reduction in the number of frosts. In addition, artificial watering of parks and gardens in the city may contribute the equivalent of 590 mm (95% CI: 450–720 mm) of extra rainfall per year. It appears that human activities have increased temperatures and effective precipitation in central Melbourne, creating a more suitable climate for camps of the grey-headed flying-fox. As demonstrated by this example, anthropogenic climate change is likely to complicate further the task of conserving biological diversity in urban environments.

Annual variation in the distribution of summer snowdrifts in the Kosciuszko alpine area, Australia, and its effect on the composition and structure of alpine vegetation

Australian alpine ecosystems are expected to diminish in extent as global warming intensifies. Alpine vegetation patterns are influenced by the duration of snow cover including the presence of snowdrifts in summer, but there is little quantitative information on landscape-scale relationships between vegetation patterns and the frequency of occurrence of persistent summer snowdrifts in the Australian alps. We mapped annual changes in summer snowdrifts in the Kosciuszko alpine region, Australia, from Landsat TM images and modelled the frequency of occurrence of persistent summer snowdrifts from long-term records (1954–2003) of winter snow depth. We then compared vegetation composition and structure among four classes that differed in the frequency of occurrence of persistent summer snowdrifts. We found a curvilinear relationship between annual winter snow depth and the area occupied by persistent snowdrifts in the following summer (r²=0.9756). Only 21 ha (0.42% of study area) was predicted to have supported summer snowdrifts in 80% of the past 50 years, while 440 ha supported persistent summer snow in 10% of years. Mean cover and species richness of vascular plants declined significantly, and species composition varied significantly, as the frequency of summer snow persistence increased. Cushion plants and rushes were most abundant where summer snowdrifts occurred most frequently, and shrubs, grasses and sedges were most abundant in areas that did not support snowdrifts in summer. The results demonstrate strong regional relationships between vegetation composition and structure and the frequency of occurrence of persistent summer snowdrifts. Reductions in winter snow depth due to global warming are expected to lead to substantial reductions in the extent of persistent summer snowdrifts. As a consequence, shrubs, grasses and sedges are predicted to expand at the expense of cushion plants and rushes, reducing landscape vegetation diversity. Fortunately, few vascular plant species (e.g. Ranunculus niphophilus) appear to be totally restricted to areas where summer snow occurs most frequently. The results from this study highlight potential indicator species that could be monitored to assess the effects of global warming on Australian alpine environments.

Above- and below-ground vertebrate herbivory may each favour a different subordinate species in an aquatic plant community

At least two distinct trade-offs are thought to facilitate higher diversity in productive plant communities under herbivory. Higher investment in defence and enhanced colonization potential may both correlate with decreased competitive ability in plants. Herbivory may thus promote coexistence of plant species exhibiting divergent life history strategies. How different seasonally tied herbivore assemblages simultaneously affect plant community composition and diversity is, however, largely unknown. Two contrasting types of herbivory can be distinguished in the aquatic vegetation of the shallow lake Lauwersmeer. In summer, predominantly above-ground tissues are eaten, whereas in winter, waterfowl forage on below-ground plant propagules. In a 4-year exclosure study we experimentally separated above-ground herbivory by waterfowl and large fish in summer from below-ground herbivory by Bewick’s swans in winter. We measured the individual and combined effects of both herbivory periods on the composition of the three-species aquatic plant community. Herbivory effect sizes varied considerably from year to year. In 2 years herbivore exclusion in summer reinforced dominance of Potamogeton pectinatus with a concomitant decrease in Potamogeton pusillus, whereas no strong, unequivocal effect was observed in the other 2 years. Winter exclusion, on the other hand, had a negative effect on Zannichellia palustris, but the effect size differed considerably between years. We suggest that the colonization ability of Z. palustris may have enabled this species to be more abundant after reduction of P. pectinatus tuber densities by swans. Evenness decreased due to herbivore exclusion in summer. We conclude that seasonally tied above- and below-ground herbivory may each stimulate different components of a macrophyte community as they each favoured a different subordinate plant species.

The effect of herbivores on genotypic diversity in a clonal aquatic plant

In clonal plants, vegetative parts may outcompete seeds in the absence of disturbance, limiting the build-up of genotypic diversity through repeated seedling recruitment (RSR). Herbivory may provide disturbance and trigger establishment of strong colonizers (seeds) at the expense of strong competitors (clonal propagules). In the clonal aquatic fennel pondweed Potamogeton pectinatus, two distinct herbivore guilds may modify the dynamics of propagation. In winter, Bewick's swans may deplete patches of tubers, promoting seedling establishment in spring. In summer, seed consumption by waterfowl can reduce the density of viable seeds but grazing may also reduce tuber production and hence facilitate seedling establishment. This study is among the first to experimentally test herbivore impact on plant genotypic diversity. We assess the separate and combined effects of both herbivore guilds on genotypic diversity and structure of fennel pondweed beds. Using microsatellites, we genotyped P. pectinatus from an exclosure experiment and assessed the contribution of herbivory, dispersal and sexual reproduction to the population genetic structure. Despite the predominance of clonal propagation in P. pectinatus, we found considerable genotypic diversity. Within the experimental blocks, kinship among genets decreased with geographic distance, clearly identifying a role for RSR in the maintenance of genotypic diversity within the fennel pondweed beds. However, over a period of five years, none of the herbivory treatments affected genotypic diversity. Hence, sexual reproduction on a local scale is important in this putatively clonal plant and possibly sufficient to ensure a relatively high genotypic diversity even in the absence of herbivores. Although we cannot preclude a role of herbivory in shaping genotypic diversity of a clonal plant, after five years of exclusion of the two investigated herbivore guilds no measurable effect on genotypic diversity was detected. © 2014 The Authors.

Seasonal variability in whale encounters in the Western Antarctic Peninsula

Cetacean sighting surveys were conducted as part of nine multidisciplinary research cruises over late summer, autumn and winter of 2 years (2001–2003) during the Southern Ocean Global Ocean Ecosystems (SO GLOBEC) program. Sea-ice cover differed markedly between years, with apparent effects on cetacean distribution. No ice was present until late June in 2001, while the previous winter sea ice never fully retreated (>30% cover) during the 2002 or 2003 summer, thus increasing the proportion of thicker and more complex ice, including multi-year floes. Humpback (237 sightings; 537 individuals) and minke (103 sightings: 267 individuals) whales were the most commonly detected species. Data from seven comparable cruises were used to identify habitat for minke and humpback whales over five geographically distinct spatial divisions in the study area. In all years, both species were predominantly found in near coastal habitat, particularly in the fjords where complex habitat likely concentrated prey. In 2002 and 2003 the presence of sea ice provided additional feeding habitat, and the numbers of minkes (in winter) and humpbacks (late summer and autumn) in the area doubled compared with 2001. Humpbacks in particular were concentrated at the ice boundaries during late summer and autumn, while minke numbers increased in the winter that followed and occupied ice-covered areas along the entire shelf edge. Important resource sites for these species are mainly located in near-coastal areas and are used in all years, but when ice margins exist and intersect with resource sites they attract much larger numbers of animals due to the dynamics between sea ice and prey.