Effectiveness monitoring of fish passage facilities: historical trends, geographic patterns and future directions

Fishways and other passage facilities frequently prevent or delay the passage of fishes, highlighting the need for effectiveness monitoring. We reviewed the scientific literature from 1960 to 2008 reporting on effectiveness monitoring of fish passage facilities to assess what taxa and life-stages have been studied, the questions that are asked during evaluation, and how these varied over time or by geographic region. We identified 96 peer-reviewed articles of which 68% focused on passage by adult fishes. Salmoniformes was the most studied order (58% of studies). The focus of fishway evaluations did not change over the years, but varied significantly by geographic region. Studies from the tropics had a broader taxonomic scope than studies from temperate locations. Exogenous mechanisms of passage failure, such as environmental, structural and behavioural factors, were studied in 90% of studies from North America but only ∼50% of studies from Europe, South America and Australia. Endogenous (i.e. physiological) mechanisms affecting passage success were not often assessed anywhere, though they were a powerful means of evaluating mechanisms of failure. Few studies monitored migration after fish had left a facility. To improve effectiveness monitoring of passage facilities, we suggest that both endogenous and exogenous mechanisms need to be studied in an integrated fashion to understand passage failure and to inform design or operational changes that could improve passage efficiency. In addition post-departure monitoring is required to more completely assess the fitness consequences of passage.     

Non-additive effects of litter-mixing on soil carbon dioxide efflux from poplar-based agroforestry systems in the warm temperate region of China

Poplar-based agroforestry systems are one of the most important farming systems on the temperate plains of China, but soil respiration in those systems has seldom been reported. In this study, poplar leaf litter and residues of the two main crops (wheat and peanut) grown in the agroforestry system were amended to form different litter mixing treatments in field experiments at two sites located in Jiangsu Province, China. We measured soil respiration and environmental factors in the different treatments. Soil respiration rates were increased by the addition of plant residues but were strongly influenced by residue quality. During the growing season, soil respiration was negatively related with C/N ratio, while positively related with the initial P concentration of residues (P < 0.05). Poplar leaf litter and crop residues showed non-additive effects on soil respiration when they were mixed. Both air and soil temperature at 10 cm depth explained more than 85 % of the variation of soil respiration at both sites with an exponential model. A significant linear relationship between soil respiration and soil water content at 10 cm depth (W_S) was also observed. The percent of variation in soil respiration explained by a model based on air temperature and soil water content was greater than that explained by a model based on temperature alone. Thus, soil respiration in the studied poplar-based agroforestry systems was driven by both temperature and soil water content. Soil respiration was significantly different between the two sites that had different clay content and C/N ratios. Results from this study are important for us to understand how soil respiration responds to litter mixing or is influenced by biophysical factors in poplar-based agroforestry systems.     

The application of knowledge synthesis methods in agri-food public health: Recent advancements,challenges and opportunities

Knowledge synthesis refers to the integration of findings from individual research studies on a given topic or question into the global knowledge base. The application of knowledge synthesis methods, particularly systematic reviews and meta-analysis, has increased considerably in the agri-food public health sector over the past decade and this trend is expected to continue. The objectives of our review were: (1) to describe the most promising knowledge synthesis methods and their applicability in agri-food public health, and (2) to summarize the recent advancements, challenges, and opportunities in the use of systematic review and meta-analysis methods in this sector. We performed a structured review of knowledge synthesis literature from various disciplines to address the first objective, and used comprehensive insights and experiences in applying these methods in the agri-food public health sector to inform the second objective. We describe five knowledge synthesis methods that can be used to address various agri-food public health questions or topics under different conditions and contexts. Scoping reviews describe the main characteristics and knowledge gaps in a broad research field and can be used to evaluate opportunities for prioritizing focused questions for related systematic reviews. Structured rapid reviews are streamlined systematic reviews conducted within a short timeframe to inform urgent decision-making. Mixed-method and qualitative reviews synthesize diverse sources of contextual knowledge (e.g. socio-cognitive, economic, and feasibility considerations). Systematic reviews are a structured and transparent method used to summarize and synthesize literature on a clearly-defined question, and meta-analysis is the statistical combination of data from multiple individual studies. We briefly describe and discuss key advancements in the use of systematic reviews and meta-analysis, including: risk-of-bias assessments; an overall quality-of-evidence approach; engagement of stakeholders; Bayesian, multivariate, and network meta-analysis; and synthesis of diagnostic test accuracy studies. We also highlight several challenges and opportunities in the conduct of systematic reviews (e.g. inclusion of grey literature, minimizing language bias, and optimizing search strategies) and meta-analysis (e.g. inclusion of observational studies and approaches to address the insufficient reporting of data and significant heterogeneity). Many of these developments have yet to be comprehensively applied and evaluated in an agri-food public health context, and more research is needed in this area. There is a need to strengthen knowledge synthesis capacity and infrastructure at the regional, national, and international levels in this sector to ensure that the best available knowledge is used to inform future decision-making about agri-food public health issues.