Integrated Approaches in Urban Storm Drainage: Where Do We Stand?

Integrated approaches to urban stormwater drainage management are being increasingly advocated as necessary for advancing more sustainable and holistic management of urban water environments. In this paper, the status of integrated approaches in the management of urban stormwater discharges to receiving waterways is summarized. The starting point of the paper is with the recent scientific contributions, revealing that integration is being pursued and implemented predominantly at two conceptual levels. These include 1) integrating the technical system with the receiving waterway environment, and 2) considering the interaction and influence of the human system with the technical system through processes such as stakeholder and public participation. Additionally, it is argued that the evolving shift towards the implementation of water-quality-based strategies advances the need for further development and application of integrated models and approaches. The cases of online physically based models for predictive control and integrated source control and public participation are presented as examples of such ongoing developments in pursuit of integrated urban stormwater management.     

Correction to: Documenting lemming population change in the Arctic: Can we detect trends?

Ambio - In the original published article, some of the symbols in figure 1A were modified incorrectly during the typesetting and publication process. The correct version of the figure is provided...     

Heavier birds react faster to predators: individual differences in the detection of stalking and ambush predators

The relationship between body mass and reactions speed in response to a predatory threat is poorly understood. Theory predicts that different vigilance patterns are optimal for the detection of different predator types. We suggest that birds of different individual state might also differ in their speed of response dependent upon predator type. We used laboratory trials of wild caught chaffinches (Fringilla coelebs) to determine how between individual differences in chaffinch behaviour and state correlate with latency to react to a ground predator model (domestic cat), thus providing a comparison with previous work in the same model system using aerial predator models. In experiment 1, we observed chaffinch responses to a moving cat model, simulating a stalking predator. In experiment 2, we used a camouflaged cat model simulating an ambush predator. Both experiments show evidence suggesting heavier individuals (which previous literature has linked to impaired flight performance) responded more quickly to the model cat. Heavier individuals also had shorter interscan intervals. In contrast to a previous study, both experiments found individuals with a higher intake rate were not faster at responding to the cat model. In addition, individuals in experiment 1 that head turned more while scanning were slower to respond to the stalking cat model. Our work suggests that although heavier individuals may have impaired escape performance they appear to show behavioural compensation by allocating more attention to anti-predator behaviour and by modifying their interscan intervals, resulting in faster response times to a ground predator. We suggest more experiments investigating response time to different predatory types and explicitly manipulating state to elucidate cause and effect.     

Synthesis and characterization of zwitterionic carbon dioxide fixing reagents

The synthesis of three amine-based carbon dioxide fixing reagents is presented. The reagents were designed so that they would be able to bind CO₂ reversibly through the formation of the well known carbamates that was stabilized through forming a zwitterion. CO₂ fixing experiments were performed with ¹³CO₂ labeling and medium pressure NMR. The experiments showed that two of the three reagents were able to form carbamates and thus bind CO₂. In addition we investigated this particular class of molecules for the possible formation of neutrally charged spiro compounds and we show that these did not form under the conditions studied.     

The ghosts of predators past: population cycles and the role of maternal programming under fluctuating predation risk

Maternal effects may be a major factor influencing the demography of populations. In mammals, the transmission of stress hormones between mother and offspring may play an important role in these effects. Laboratory studies have shown that stressors during pregnancy and lactation result in lifelong programming of the offspring phenotype. However, the relevance of these studies to free-living mammals is unclear. The 10-year snowshoe hare (Lepus americanus) cycle is intimately linked to fluctuating predation pressure and predation risk. The enigma of these cycles is the lack of population growth following the decline phase, when the predators have virtually all disappeared and the food supply is ample. We have shown that a predator-induced increase in maternal stress hormone levels resulted in a decline in reproduction. Here we examine population and hormone changes over a four-year period from the increase (2005) to the decline (2008). We report (1) that an index of maternal stress (fecal corticosteroid metabolite [FCM] concentrations) fluctuates in synchrony with predator density during the breeding season; (2) that maternal FCM levels are echoed in their offspring, and this occurs at a population-wide level; and (3) that higher maternal FCM levels at birth are correlated with an increased responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis in their progeny. Our results show an intergenerational inheritance of stress hormones in a free-ranging population of mammals. We propose that the lack of recovery of reproductive rates during the early low phase of the hare cycle may be the result of the impacts of intergenerational, maternally inherited stress hormones caused by high predation risk during the decline phase.     

Optimal foraging and territorial defence in the Great Tit (Parus major)

Summary We describe an experiment designed to investigate the trade-off between foraging and territorial vigilance in the Great Tit. Captive territorial male Great Tits were observed while foraging in a large indoor aviary. They obtained food from two operant patches in which the supply of food was gradually depleted during a visit. We predicted that during control sessions the birds would switch between patches in such a way as to maximise their overall feeding rate. In experimental sessions, we introduced briefly a rival male as an intruder at the start of the test. The foraging male could see the rival only when travelling between patches and not while feeding within patches. We predicted that during experimental sessions birds would switch between patches more often than in control tests, sacrificing food intake for territorial vigilance. Three of the four males tested behaved in approximately the predicted manner. We discuss the use of an inverse optimality argument to provide a calibration of feeding against the benefit resulting from territorial vigilance.