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Zizania palustris L. (northern wild rice, NWR) is an aquatic grass native to North America that is notable for its nutritious grain. This is an important species with ecological, cultural and agricultural significance, specifically in the Great Lakes region of the USA. Using flow cytometry, we first estimated the NWR genome size to be 1.8 Gb. Using long- and short-range sequencing, Hi-C scaffolding and RNA-seq data from eight tissues, we generated an annotated whole-genome de novo assembly of NWR. The assembly was 1.29 Gb in length, highly repetitive (approx. 76.0%) and contained 46 421 putative protein-coding genes. The expansion of retrotransposons within the genome and a whole-genome duplication (WGD) after the Zizania-Oryza speciation event have both led to an increase in the genome size of NWR in comparison with Oryza sativa L. and Zizania latifolia. Both events depict a genome rapidly undergoing change over a short evolutionary time. Comparative analyses revealed the conservation of large syntenic blocks between NWR and O. sativa, which were used to identify putative seed-shattering genes. Estimates of divergence times revealed that the Zizania genus diverged from Oryza approximately 26-30 million years ago (26-30 MYA), whereas NWR and Z. latifolia diverged from one another approximately 6-8 MYA. Comparative genomics confirmed evidence of a WGD in the Zizania genus and provided support that the event occurred prior to the NWR-Z. latifolia speciation event. This genome assembly and annotation provides a valuable resource for comparative genomics in the Oryzeae tribe and provides an important resource for future conservation and breeding efforts of NWR., (© 2021 Society for Experimental Biology and John Wiley & Sons Ltd.)

Sleep is important for memory consolidation and maintaining metabolic homeostasis, but sleep can expose animals to inclement weather and predators. Consequently, selection of sleeping sites is important. We tested three sets of hypotheses related to selection of bed sites by female American black bears (Ursus americanus) at two study sites. During 2009–2013, we outfitted 14 female black bears west of Ely, Minnesota, with Global Positioning System collars that reported bear locations every 10 min. We visited 101 bed sites, each identified from clusters of estimated locations where a bear was on site for ≥4 h on two or more occasions, and recorded bed characteristics, forest composition, canopy closure, and ground cover. We matched each bed site with a control site where we collected the same data. During 1987–1991, we outfitted three female black bears south of Ely with very high-frequency transmitter collars and walked with the bears to collect detailed behavioral data. We used the written data records to identify 62 bed sites where bears slept ≥2 h and where bed characteristics were documented. We matched each bed site with a control site approximately 6 h different when the bear was active. Of the bed sites, 132 were used during night and 31 during day. The two study areas differed in the amount of lowland habitats. At both sites, female bears chose bed sites disproportionately in lowland sites with high canopy cover and next to a tree, especially a white pine. Female bears with cubs selected upland bed sites more often than did females without cubs and also more often selected sites adjacent to a tree with coarse bark, which cubs could climb easily. Distances to roads and houses did not affect selection of bed sites by females either with or without cubs. [ABSTRACT FROM AUTHOR]

Declining populations of Zizania palustris L. (northern wildrice, or wildrice) during the last century drives the demand for new and innovative techniques to support monitoring of this culturally and ecologically significant crop wild relative. We trained three wildrice detection models in R and Google Earth Engine using data from annual aquatic vegetation surveys in northern Minnesota. Three different training datasets, varying in the definition of wildrice presence, were combined with Landsat 8 Operational Land Imager (OLI) and Sentinel-1 C-band synthetic aperture radar (SAR) imagery to map wildrice in 2015 using random forests. Spectral predictors were derived from phenologically important time periods of emergence (June–July) and peak harvest (August–September). The range of the Vertical Vertical (VV) polarization between the two time periods was consistently the top predictor. Model outputs were evaluated using both point and area-based validation (polygon). While all models performed well in the point validation with percent correctly classified ranging from 83.8% to 91.1%, we found polygon validation necessary to comprehensively assess wildrice detection accuracy. Our practical approach highlights a variety of applications that can be applied to guide field excursions and estimate the extent of occurrence at landscape scales. Further testing and validation of the methods we present may support multiyear monitoring which is foundational for the preservation of wildrice for future generations. [ABSTRACT FROM AUTHOR]