Darren G. Bos

Restoring a stream through retention of urban stormwater runoff: a catchment-scale experiment in a social–ecological system

Restoration of ecological structure and function of urban streams probably requires catchment-scale modification of drainage infrastructure, but such catchment-scale restoration attempts and their assessment are rare. They require stream ecologists to embrace the interdisciplinary challenges of studying the social–ecological systems that are urban catchments. We designed and monitored a catchment-scale experiment that involved the retrofit of urban stormwater infrastructure throughout an urban catchment to restore more natural hydrology, water quality, and consequently, ecological condition in the receiving stream. We worked with government authorities and the catchment community (residents and property owners) over several years to fund and implement 289 stormwater retention systems. The length of the project allowed adaptation of the experimental design to expand the project’s breadth and of retention-system design to match community needs and catchment context. Planning provisions are particularly important for such an experiment to ensure that the effect of dispersed experimental treatments is not countered by creation of new connected impervious areas elsewhere in the catchment. Catchment-scale experiments can help to transform policy and practice, but their success requires substantial effort and time to build trust among the numerous, diverse stakeholders of human-dominated urban ecosystems. Researchers need to be prepared to adopt an adaptive approach to the implementation of such experiments and to play the lead role in seeking funds for the implementation of the on-ground works necessary to underpin the experiment.

More than money: how multiple factors influence householder participation in at-source stormwater management

Urban stormwater run-off is a threat to stream ecosystems. New approaches to stormwater management aim to protect urban streams from such impacts, by retaining, treating and using stormwater at its source. As up to ∼50% of runoff from urban surfaces comes from private property, fostering stormwater retention requires effective householder engagement. We evaluated householder participation in the Little Stringybark Creek project, a stormwater retrofit programme aimed at waterway protection, using qualitative enquiry through formal and informal interviews to identify factors that influenced participation. Participation was governed by multiple factors, with financial incentives and personal co-benefits of tanks primary motivators, while process complexity and distrust were primary barriers. Results suggest an approach combining education to encourage review of subjective norms and attitudes, with incentives to mitigate behavioural controls can transform public behaviour towards sustainable stormwater management.

Overcoming barriers to community participation in a catchment-scale experiment: building trust and changing behavior

Communities have an important role to play in the protection of urban streams, particularly with how stormwater runoff from their properties is managed. As part of a larger research project, we used 3 sequential approaches to engage communities in protecting their local creek by managing their properties’ stormwater runoff. We assessed their success through surveys and measurements of uptake. Our initial efforts elicited strong interest from the community, but participation rates were greatest when the application process was simplified and barriers to participation were removed. The sequential implementation of the approaches limits inference of their comparative effectiveness, but the results suggest that the iterative and adaptive nature and extended period of the process facilitated the targeting of diverse motivations and the building of community trust, which in turn led to greater community participation.

Population ecology of Ningaui yvonneae (Dasyuridae : Marsupialia) in the Middleback Ranges, Eyre Peninsula, South Australia

A population of the southern ningaui (Ningaui yvonneae) was studied in the semi-arid regions of South Australia. Data were collected on the population ecology of the species, including capture success, breeding biology and life history. Between August 1996 and December 1998, 307 captures were recorded from 11 016 trap-nights. Most individuals were caught only once and males were caught more frequently than females. Capture success varied greatly between seasons, with lowest captures being recorded in winter. Winter is a time of stress for N. yvonneae – mean weights stabilised between March and June. N. yvonneae is polyoestrous, with mating recorded from September to February. However, most matings took place in mid-October. The population was dominated by a single cohort, with the life span for N. yvonneae being approximately 14 months.

Prey selection by the dasyurid Ningaui yvonneae

We know little about the availability of potential prey and patterns of prey consumption by Ningaui yvonneae in a natural environment. This information is important to understanding how the species is able to exploit its semiarid environment. Here, we examine the diet of N. yvonneae inhabiting a semiarid mallee community in South Australia using a combination of faecal analysis and observations of nocturnally foraging animals. Prey consumption was compared with the availability of prey types in the environment, and comparisons made between habitat components, across seasons and between sexes. N. yvonneae was found to include a range of prey types in its diet, with 11 invertebrate taxa recorded from direct observation and eight of these detected in the scats. Prey taxa consumed most often by freely foraging ningauis were Araneae, Blattodea and Orthoptera, while those most commonly detected in scats were Hymenoptera and Araneae. In comparison, 22 invertebrate taxa were recorded in pitfall traps, although many of these were recorded infrequently. Taxa most commonly recorded in traps were Hymenoptera, Collembola, Coleoptera and Acariformes. Observational data also indicated that consumption of prey taxa differed significantly between sexes and among seasons. Males generally consumed a more diverse array of prey, with both observational and scat data showing that they were more likely to consume Hymenoptera and Isoptera, while females were more likely to consume Lepidoptera and Hemiptera. Variability between seasons was evident in consumption of invertebrate grubs (recorded only during ‘growth’; February–April), Orthoptera (recorded most often during ‘breeding’, August–October), and Araneae (recorded more often during ‘maturation’, May–July). However percentage occurrence data from the scats lacked this seasonality, possibly because of the smaller array of prey taxa recorded. N. yvonneae captured prey from all available habitat components, with five of the most frequently recorded prey taxa being recorded from all components. Leaf litter and Triodia were the most commonly recorded capture sites (45% and 22% of captures respectively), and males and females used the habitat components in a similar manner. Although N. yvonneae is like many other dasyurids in having a largely generalist insectivorous diet, comparisons of prey consumed with their availability in the environment indicated that individuals did show some selectivity towards certain taxa, particularly Blattodea, Orthoptera, Chilopoda, Lepidoptera and Araneae.

Patterns of movement in the small dasyurid (Ningaui yvonneae)

The movement behaviour of a small dasyurid (Ningaui yvonneae) was investigated using mark–recapture data collected over 28 months from a population in the Middleback Ranges, South Australia. We were particularly interested in assessing variability in patterns of movement between the sexes and across seasons, as this has potentially important implications for population composition and dynamics. The species was found to be fairly mobile, with frequent and sometimes large movements relative to the size of the animal (up to 900+ m). Average distances moved between recaptures within and between trap sessions were 84 m and 160 m respectively, with nearly half of all recorded movements being between trapping grids (i.e. >80 m). Relatively high recapture rates (many separated by more than 100 days) and measures of site fidelity indicated that the species was not particularly transitory, but probably establishes large and/or drifting home ranges. However, patterns of movement varied considerably according to sex and the time of year. Female N. yvonneae were generally more sedentary than males, with few females moving between trapping grids, and most short-term movements ( 200 m. In contrast, males often moved between trapping grids, even over short periods. Some short-term movements were more than 600 m in length, and the average distance moved within trapping sessions was >100 m. During the breeding season, males more than doubled the average distances moved between recaptures, when they were presumably roaming in search of females. For females, movement distances were similar during the prebreeding and breeding seasons, but were significantly smaller in the postbreeding season, when they were caring for young.