Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2024
Abstract
Mapping individual tree quality parameters from high-density LiDAR point clouds is an important step towards improved forest inventories. We present a novel machine learning-based workflow that uses individual tree point clouds from drone laser scanning to predict wood quality indicators in standing trees. Unlike object reconstruction methods, our approach is based on simple metrics computed on vertical slices that summarize information on point distances, angles, and geometric attributes of the space between and around the points. Our models use these slice metrics as predictors and achieve high accuracy for predicting the diameter of the largest branch per log (DLBs) and stem diameter at different heights (DS) from survey-grade drone laser scans. We show that our models are also robust and accurate when tested on suboptimal versions of the data generated by reductions in the number of points or emulations of suboptimal single-tree segmentation scenarios. Our approach provides a simple, clear, and scalable solution that can be adapted to different situations both for research and more operational mapping.
Authors
Kalkidan Mulatu Ayele Shimelis Gizachew Raji Bimrew Asmare Niklas Wickander Solomon Mwendia Peter Dörsch W. A. Worku Caroline Brophy Karl Thunes Marit JørgensenAbstract
EthiopiaGrass Fact sheet. 1 p.
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Authors
Jihong Liu ClarkeAbstract
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Jorunn BørveAbstract
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Abstract
River Otter (Lontra canadensis) was extirpated from Prince Edward Island (PEI) in the early 1900s as a result of habitat loss and overexploitation. Although there were isolated and sporadic occurrences in PEI coastal and inland waters pre-1975, only anecdotal reports of tracks or sightings of the species had been documented in the 21st century, until an adult male otter was captured in a beaver trap in 2016. Since then, seven additional individuals have been collected opportunistically or as by-catch of beaver trapping, including an adult female and a kit (juvenile). Camera traps have also revealed what appears to be a family group in central PEI. A growing body of evidence strongly suggests a resident River Otter population on PEI. The island is separated from the mainland by the Northumberland Strait, which has a minimum width of 13 km of salt water. River Otters have naturally recolonized PEI by dispersing across the Northumberland Strait.
Abstract
Gaining the ability to fly actively was a ground-breaking moment in insect evolution, providing an unprecedented advantage over other arthropods. Nevertheless, active flight was a costly innovation, requiring the development of wings and flight muscles, the provision of sufficient energetic resources, and a complex flight control system. Although wings, flight muscles, and the energetic budget of insects have been intensively studied in the last decades, almost nothing is known regarding the flight-control devices of many crucial insect groups, especially beetles (Coleoptera). Here, we conducted a phylogenetic-informed analysis of flight-related mechanosensors in 28 species of bark beetles (Curculionidae: Scolytinae, Platypodinae), an economically and ecologically important group of insects characterized by striking differences in dispersal abilities. The results indicated that beetle flight apparatus is equipped with different functional types of mechanosensors, including strain- and flow-encoding sensilla. We found a strong effect of allometry on the number of mechanosensors, while no effect of relative wing size (a proxy of flight investment) was identified. Our study constitutes the first step to understanding the drivers and constraints of the evolution of flight-control devices in Coleoptera, including bark beetles. More research, including a quantitative neuroanatomical analysis of beetle wings, should be conducted in the future.>