The effects of the non-native invertebrate predator Bythotrephes longimanus and declining aqueous calcium on crustacean zooplankton communities in Canadian Shield lakes

Over the last several decades, human activities have resulted in environmental changes that have increased the number of stressors that can act on a single environment. In Canadian Shield lakes, two recent stressors, the invasion of Bythotrephes longimanus and calcium decline, have been documented. Widespread acidification of hundreds of North American lakes has resulted in the precipitous decline of lake water calcium concentration. Crustacean zooplankton with high calcium demands are likely to be vulnerable to calcium decline, especially <1.5 mg Ca/L, where survival and reproduction rates are reduced. These taxa are also vulnerable to predation by Bythotrephes that has been implicated in the loss of pelagic biodiversity in soft water lakes. Despite laboratory and field studies aimed at understanding the independent impact of these stressors, it is unclear how their co-occurrence will influence community response. Using a combination of data from a large regional lake survey and field experiments, I examined the individual and joint effects of Bythotrephes and calcium decline on native zooplankton community structure. Results demonstrated that much is known about Bythotrephes and our findings of reduced total zooplankton and species richness, due to the loss of Cladocera, are consistent with field surveys and other experimental studies. While we did not detect strong evidence for an effect of calcium on zooplankton using the lowest calcium concentration among invaded lakes (1.2 mg Ca/L), there is evidence that, as lake water calcium concentrations fall <1 mg Ca/L, per capita growth rates of a broad variety of taxa are expected to decline. At the regional scale, negative effects of Bythotrephes and calcium on abundances of small cladocerans and Daphnia pulicaria, respectively, were in agreement with my experimental observations. We also observed significant interactions between Bythotrephes and calcium for a broad variety of taxa. As Bythotrephes continues to spread and invade lakes that are also declining in aqueous calcium, both stressors are likely to amplify negative effects on Cladocera that appear the most vulnerable. Loss of these important zooplankton in response to both Bythotrephes and calcium decline, is likely to lower zooplankton productivity, with potential effects on phytoplankton and higher trophic levels.

A HARD PUSH FOR SOFT SKILLS: AN EXAMINATION OF POLICY AND RESEARCH ON NON-COGNITIVE SKILLS IN CANADIAN K-12 SCHOOLING

Non-cognitive skills have caught the attention of current education policy writers in Canada. Within the last 10 years, almost every province has produced a document including the importance of supporting non-cognitive skills in K-12 students in the classroom. Although often called different names (such as learning skills, cross curricular competencies, and 20th Century Skills) and occasionally viewed through different lenses (such as emotional intelligence skills, character skills, and work habits), what unifies non-cognitive skills within the policy documents is the claim that students that are strong in these skills are more successful in academic achievement and are more successful in post-secondary endeavors. Though the interest from policy-makers and educators is clear, there are still many questions about non-cognitive skills that have yet to be answered. These include: What skills are the most important for teacher’s to support in the classroom? What are these skills’ exact contributions to student success? How can teachers best support these skills? Are there currently reliable and valid measures of these skills? These are very important questions worth answering if Canadian teachers are expected to support non-cognitive skills in their classrooms with an already burdened workload. As well, it can begin to untangle the plethora of research that exists within the non-cognitive realm. Without a critical look at the current literature, it is impossible to ensure that these policies are effective in Canadian classrooms, and to see an alignment between research and policy. Upon analysis of Canadian curriculum, five non-cognitive skills were found to be the most prevalent among many of the provinces: Self-Regulation, Collaboration, Initiative, Responsibility and Creativity. The available research literature was then examined to determine the utility of teaching these skills in the classroom (can students improve on these skills, do these skills impact other aspects of students’ lives, and are there methods to validly and reliably assess these skills). It was found that Self-Regulation and Initiative had the strongest basis for being implemented in the classroom. On the other hand, Creativity still requires a lot more justification in terms of its impact on students’ lives and ability to assess in the classroom.