Farmers, food supply-chain entities, and policymakers need a simple but robust indicator to demonstrate progress toward reducing nitrogen pollution associated with food production. We show that nitrogen balance—the difference between nitrogen inputs and nitrogen outputs in an agricultural production system—is a robust measure of nitrogen losses that is simple to calculate, easily understood, and based on readily available farm data.

Effective habitat restoration requires an understanding of species habitat preferences and the associated mechanisms driving those preferences. We examined the patterns and causes of oviposition preference in the monarch butterfly, a rapidly declining species, in southwestern Ontario at both landscape and milkweed patch spatial scales. Additionally, we measured the abundance of invertebrate predators, parasitoids and parasites across these same spatial scales.

Ambient air pollution is a major health risk globally. To reduce adverse health effects on days when air pollution is high, government agencies worldwide have implemented air quality alert programmes. Despite their widespread use, little is known about whether these programmes produce any observable public-health benefits. We assessed the effectiveness of such programmes using a quasi-experimental approach.

Original Source

Many policy interventions intended to benefit public health can only be evaluated as so-called natural experiments, because implementation is not controlled by researchers seeking to assess effectiveness. Such assessments can be complicated by non-comparability between people affected and not affected by the intervention. Various quasi-experimental designs have been proposed to address this problem of non-comparability, one being the regression discontinuity design, which has had little use in public health.

Constructing complete, accurate plant DNA barcode reference libraries can be logistically challenging for large-scale floras. Here we demonstrate the promise and challenges of using herbarium collections for building a DNA barcode reference library for the vascular plant flora of Canada.

Original Source

The Mactaquac Dam and Generating Station, a 672 MW run-of-the-river hydroelectric facility located on the Saint John River, Canada, will have to be decommissioned or reconstructed by 2030. In order to simulate the impact of reservoir emptying (drawdown) and climate change on the thermal regime of the lower reaches of the river, the CEQUEAU hydrological and water temperature model was used.