Patterns of vegetation structural diversity across heterogeneous landscapes in southwestern Nova Scotia

1 online resource (88 pages) : colour illustrations, colour maps, colour charts, graphs (some colour)Includes abstract and appendices.Includes bibliographical references (pages 14-21, 45-52, 74-81).Forest edges, including transitional areas between forest and non-forest areas, outline the overall structure of the landscape. To assess and quantify patterns of structural diversity across natural and harvested landscapes in southwestern Nova Scotia, I used field-based structural diversity metrics and UAV imagery along two 1250 m transects to examine different aspects of the pattern of structural diversity across transitions in forested landscapes. For traditional field metrics, tree structural diversity had more success in determining transitions than functional plant group diversity, as tree structural diversity detected all edge types compared to just anthropogenic edges when using functional plant group diversity. For photogrammetrically derived metrics, no metric detected transitions at all edges and overall UAV metrics were incompatible with field sampling. Future studies should examine the compatibility of LiDAR and structural diversity metrics

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data