Effects of introduced trout predation on non-diadromous galaxiid fish populations across invaded riverscapes

Abstract We assessed the landscape-scale effect of predation pressure from trout on the population integrity and distributions of non-diadromous galaxiids in high-country streams of the South Island, New Zealand. The effects of trout (brown trout, Salmo trutta, and rainbow trout, Oncorhynchus mykiss) on two widespread species, the Canterbury galaxias (Galaxias vulgaris Stokell) and the alpine galaxias (G. paucispondylus Stokell) were assessed. Experiments confirmed that both species were vulnerable to trout predation and that habitat (size and disturbance regime) may be a factor in local co-occurrence. Quantitative electrofishing surveys indicated that G. paucispondylus distributions were less affected by trout than G. vulgaris distributions and that the species’ range was limited by temperature. Trout created demographic sinks for G. vulgaris across most invaded reaches, while refuge populations in streams above barriers to trout acted as demographic sources for this species. G. vulgaris was consistently absent from small, stable stream reaches far from sources, indicating that trout predation pressure and propagule pressure (driven by immigration from sources) interact to drive local G. vulgaris persistence in trout-invaded reaches. Predation pressure is likely to be highest in areas where infrequent flooding allows high densities of large trout (> 150 mm FL) to occur and where there are few refugia for galaxiids. A spatial model was developed to predict exclusion of galaxiids by trout across invaded networks. If used appropriately, the model could be used to find new refuge populations of non-diadromous galaxiids and to aid planning of active rehabilitation of trout-invaded river networks

Caregiver Treatment Consumption in an Experimental Treatment Marketplace

Behavioral economics is an approach to understanding consumer behavior by integrating behavioral science with economic principles. Behavioral economics incorporates traditional economic principles with operant learning approaches. There is limited research examining how individuals consume psychological and behavioral treatments. This is especially the case for treatments designed for children. The current study used data from a previously collected sample to explore gender differences in an experimental treatment marketplace (ETM). Experimental treatment marketplaces are generally used to evaluate choices between goods and services (e.g., types of behavior interventions). An ETM was developed to evaluate treatment consumption when levels of evidence differed between prospects. Results indicated that parents substituted an evidence-based treatment with an alternative treatment when associated costs and effort increased, regardless of evidence of the alternative treatment. Further analyses revealed that the rate of substitution did not differ significantly between mothers and fathers. These findings are discussed and reviewed in the context of advocating for treatments with documented efficacy

The impact of alien invasive smallmouth bass (Micropterus dolomieu) on the indigenous fish of the Rondegat River : a quantitative assessment with implications for rehabilitation

Alien invasive fishes are a growing concern in inland water ecosystems around the world, as they are capable of causing serious damage, especially to indigenous fish populations. Mechanisms include direct predation on indigenous fish by alien predatory species, competition for food and space between native and introduced species, the introduction of alien parasites and pathogens, and general environmental degradation. The Cape Floristic Region (CFR) of South Africa, which is defined by a unique and highly diverse floral kingdom, is also home to a unique and highly threatened ichthyofauna. This ichthyofauna consists of relatively few species, but exhibits the highest proportion of endemicity in the country. Threats to fishes include habitat destruction through bulldozing and water extraction, water quality degradation, restriction of migration by dams and weirs, and alien invasive fishes. The North American smallmouth bass (Micropterus dolomieu Lacepede) has long been regarded by nature conservators as the most threatening invasive species, and much anecdotal and survey data suggests that this species has had a major role in the depletion and extirpation of indigenous fish populations throughout the CFR. However, no study has ever properly quantified this impact relative to other potential threats that could have precipitated the perceived indigenous fish losses. This is a problem, as it makes the implementation of active control measures difficult to justify to a sceptical public and potential sponsors. The Rondegat River is a tributary of the Olifants River, which rises in the Cedarberg Mountains and flows into the Clanwilliam Dam reservoir. It is partially invaded by M dolomieu, which have penetrated the lower quarter of the river up to a waterfall barrier. This river is home to five species of indigenous fish, including the Clanwilliam yellowfish (Labeobarbus capensis Smith), Clanwilliam redfin (Barbus calidus Barnard), fiery redfin (Pseudobarbus phlegethon Barnard), Clanwilliam rock catfish (Austroglanis gilli Barnard) and the Cape galaxiid (Galaxias zebratus Castelnau). This project was designed to quantify the impact of M dolomieu on these species relative to the alternate potential impacts of physical habitat degradation from agriculture and alien invasive riparian trees, and of food availability. Seasonal surveys were conducted at eight sites on the river in September, October and November 2003, and in April 2004. Four sets of riffles and pools were selected upstream of the waterfall barrier, and four below. Quantitative electrofishing was used to survey fish in riffles, while snorkelling surveys were conducted in pools. All fish species were also caught with seine and tyke nets for dietary analyses. Physical habitat variables were measured at each site, and used to assess changing habitat quality between the sites. Invertebrate samples were also taken along with visual abundance estimations of other food types, to gauge food availability. Fish surveys revealed the loss of B. calidus, P. phlegethon, A. gilli and G. zebratus at bass-invaded sites. Galaxias zebratus was only found in the upper reaches of the river, and so was possibly never common in the lower river. Labeobarbus capensis, while still below the waterfall, appeared to be suffering from near-total loss of post spawning recruits. Discriminant function analyses revealed sedimentation to be a key factor of habitat degradation that characterized invaded sites. However, linear regressions between habitat variables and indigenous fish densities indicated sedimentation to not be a significant negative influence on indigenous fish distributions. Although sedimentation did not appear to influence A. gilli densities at non-invaded sites, it is highly likely that it increased the vulnerability of this species to M dolomieu in the lower river, by removing benthic cover used to avoid predation. In the case of all species, food availability did not seem an important factor in dictating fish distributions. Consequently, predation by M dolomieu was confirmed as the critical mechanism behind the loss of B. calidus, P. phlegethon, A.gilli and juvenile L. capensis in the lower river. A rehabilitation plan is proposed for the Rondegat River. Central to this plan is the formation of a conservancy between the land-owners of the catchment and the custodians of the Cedarberg Wilderness Area. The most effective strategy will be to eradicate M dolomieu from the lower river with piscicides, while at the same time taking steps to rehabilitate the riparian zone throughout the river. A holistic rehabilitation programme such as this would provide an excellent model for future rehabilitation efforts within the CFR

AN INVESTIGATION OF SCHEMA THEORY APPLIED TO THE BIOMECHANICS OF THE SPRINT START IN ATHLETICS

Schmidt’s schema theory (1975) predicts that variable practice (VP) will outperform constant practice (CP). The implications of this for the teaching of skills such as the sprint start are that VP should allow equal or better learning to CP. The aim of this study was to examine the effect on novice subjects of practicing with varying block settings on the learning of the sprint start. A deterministic model of the spint start was derived using the guidelines of Hay and Reid (1982) to identify factor likely to affect performance. Measures of the factors were obtained using video and laser analysis. The affect of VP and CP on these factors was evaluated using a pre, post retention expermental design. Performance of the sprint start was compared between VP (n=6), CP (n=5), and Control (n=5) groups. Results showed no significant difference (

AN INVESTIGATION OF SCHEMA THEORY APPLIED TO THE BIOMECHANICS OF THE SPRINT START IN ATHLETICS

Schmidt’s schema theory (1975) predicts that variable practice (VP) will outperform constant practice (CP). The implications of this for the teaching of skills such as the sprint start are that VP should allow equal or better learning to CP. The aim of this study was to examine the effect on novice subjects of practicing with varying block settings on the learning of the sprint start. A deterministic model of the spint start was derived using the guidelines of Hay and Reid (1982) to identify factor likely to affect performance. Measures of the factors were obtained using video and laser analysis. The affect of VP and CP on these factors was evaluated using a pre, post retention expermental design. Performance of the sprint start was compared between VP (n=6), CP (n=5), and Control (n=5) groups. Results showed no significant difference (

Depictions and Gaps: Portrayal of U.S. Poverty in Realistic Fiction Children’s Picture Books

Researchers conducted a critical multicultural analysis of 58 realistic fiction children’s picture books that portray people living in poverty and compared these depictions to recent statistics from the United States Census Bureau. The picture books were examined for the following qualities: main character, geographic locale and time era, focal poor character (gender, age, and race), who demonstrated action, and the type of action (individual, community, systemic) demonstrated. Results of the analysis showed that while in some areas the books accurately reflect the reality in the United States today, there are other areas in which poverty is misrepresented. For example, while the attribute of gender was found to be accurately reflected in the literature, depictions of contemporary rural poverty as well as action performed at the systemic level are seemingly absent. The analysis concludes with implications for teaching as well as recommended books to consider for inclusion in a classroom library

So Many Hopes : A Qualitative Content Analysis of Children\u27s Picture Books that Portray Refugees

Researchers used content analysis to analyze 40 award-winning and “best of” children’s picture books that portray refugees to answer the questions: How are refugees depicted in picture books? What messages are embedded in those depictions? Results show patterns and themes regarding depictions of trauma and violence in conjunction with setting as well as the portrayal of the arts as a vehicle for refugees to ignite personal agency in coping with the trauma they experienced. Implications for practice are discussed

V

Several methods were used to estimate Vs30 from site profiles with borehole depths of about 20 m for the strong-motion stations located in Southwest China. The methods implemented include extrapolation (constant and gradient), Geomatrix Site Classification correlation with shear-wave velocity, and remote sensing (terrain and topography). The gradient extrapolation is the preferred choice of this study for sites with shear-wave velocity profile data. However, it is noted that the coefficients derived from the California data set are not applicable to sites in Southwest China. Due to the scarcity of borehole profiles data with depth of more than 30 m in Southwest China, 73 Kiknet profiles were used to generate new coefficients for gradient extrapolation. Fortunately, these coefficients provide a reasonable estimate of Vs30 for sites in Southwest China. This study showed Vs30 could be estimated by the time-average shear-wave velocity (average slowness) of only 10 meters of depth. Furthermore, a median Vs30 estimate based upon Geomatrix Classification is derived from the results of the gradient extrapolation using a regional calibration of the Geomatrix Classification with Vs30. The results of this study can be applied to assign Vs30 to the sites without borehole data in Southwest China