Article
Environmental Sciences
Barbara D'hont, Kim Calders, Harm Bartholomeus, Tim Whiteside, Renee Bartolo, Shaun Levick, Sruthi M. Krishna Moorthy, Louise Terryn, Hans Verbeeck
Summary: This study investigates the use of UAV-based observations for precise and scalable termite mound detection and morphological characterisation. The results show that UAV-LS data can be rapidly acquired and provide higher spatial detail for monitoring and mapping termite mounds over relatively large areas compared to airborne and spaceborne remote sensing techniques.
Article
Environmental Sciences
Luiz Felipe Ramalho de Oliveira, H. Andrew Lassiter, Ben Wilkinson, Travis Whitley, Peter Ifju, Stephen R. Logan, Gary F. Peter, Jason G. Vogel, Timothy A. Martin
Summary: Unmanned aircraft systems (UAS) have rapidly advanced in technology, allowing for low-cost capture of high-resolution images for deriving three-dimensional photogrammetric point clouds. This study evaluates the quality of three-dimensional datasets from two cameras and one lidar sensor collected over a managed pine stand with different planting densities. The results show that the higher-quality camera photogrammetric data is sufficient for individual tree detection and height determination, but lidar data is best overall. The automated tree detection algorithm performed well with lidar data, but slightly fell short in comparison to manual mensuration within the lidar point cloud.
Article
Environmental Sciences
Gregoire Vincent, Philippe Verley, Benjamin Brede, Guillaume Delaitre, Eliott Maurent, James Ball, Ilona Clocher, Nicolas Barbier
Summary: Leaf area is a crucial feature of forest canopies, and Airborne Laser Scanning (ALS) can provide accurate estimates of plant area density. However, inconsistencies between ALS sensors hinder the generation of globally harmonised estimates. This study shows that differences in scanner characteristics lead to discrepancies in light attenuation estimates, emphasizing the need for intercalibration procedures.
REMOTE SENSING OF ENVIRONMENT
(2023)
Article
Environmental Sciences
Harm Bartholomeus, Kim Calders, Tim Whiteside, Louise Terryn, Sruthi M. Krishna Moorthy, Shaun R. Levick, Renee Bartolo, Hans Verbeeck
Summary: In vegetation monitoring, it is important to understand the changes caused by measurement setup and true representations of vegetation dynamics. This study examines the differences in derived forest metrics using three different UAV-LiDAR systems in a savanna woodland. The findings show that all three systems can accurately derive plot characteristics, but clear differences exist between metrics derived with different sensors, particularly in the lower parts of the canopy. It is crucial to be aware of these differences when comparing UAV-LiDAR data of forest areas through time.
Article
Environmental Sciences
Megan Winsen, Grant Hamilton
Summary: LiDAR has been the preferred tool for 3D dense point cloud reconstructions of forest canopy, but structure from motion (SfM) photogrammetry based on aerial imagery has emerged as a powerful and low-cost alternative. However, comparing and assessing the accuracy of different reconstructions remains a challenge. This study compared LiDAR and SfM-NIR reconstructions of a native eucalypt forest and found that neither method accurately reproduced canopy cover or predicted tree heights. The LiDAR product showed better representation of the eucalypt canopy compared to SfM-NIR, which was affected by a lack of data and sub-optimal feature matching. Future studies could explore combining NIR imagery captured at different solar elevations and optimize image feature matching.
Article
Environmental Sciences
Baokun Feng, Sheng Nie, Cheng Wang, Xiaohuan Xi, Jinliang Wang, Guoqing Zhou, Haoyu Wang
Summary: This paper explores the potential of UAV-based LiDAR for trunk point extraction and direct diameter at breast height (DBH) measurement. The proposed method achieves high accuracy in trunk point extraction and DBH measurement using UAV LiDAR data. The study also demonstrates the influence of scanning angle and mode on the extraction and measurement process.
Article
Ecology
Derek J. N. Young, Michael J. Koontz, JonahMaria Weeks
Summary: Recent advances in technology allow for individual tree mapping in forests using low-cost equipment and minimal data collection. Researchers tested different methods for collecting and processing imagery, as well as tree detection, and found an efficient and accurate method for creating tree maps.
METHODS IN ECOLOGY AND EVOLUTION
(2022)
Article
Environmental Sciences
Johanna Roiha, Einari Heinaro, Markus Holopainen
Summary: The study tested drone-based ALS as an archaeological site survey tool in a complex forested area, demonstrating good results in increasing understanding of the site and its structures, but more research is needed on the impact of forest cover on accuracy.
Article
Chemistry, Analytical
Muhammad Hamid Chaudhry, Anuar Ahmad, Qudsia Gulzar, Muhammad Shahid Farid, Himan Shahabi, Nadhir Al-Ansari
Summary: The study examines the use of low-cost UAV data for high spatial resolution 3D modeling of the Earth and investigates the impact of image radiometric transformation techniques on the accuracy of DSM. Results show a significant improvement in accuracy of enhanced DSM after radiometric transformation.
Article
Environmental Sciences
S. Garcia-Lopez, M. Velez-Nicolas, P. Zarandona-Palacio, A. C. Curcio, V. Ruiz-Ortiz, L. Barbero
Summary: In this research, a novel methodology using drone-borne LiDAR observations is proposed to remotely acquire information on the piezometric level from traditional large-diameter wells. This method has been applied in a small coastal aquifer with numerous wells as monitoring points. The results show that the UAV-LiDAR technique provides more accurate measurements compared to the official DTM data, allowing for the monitoring of extensive or inaccessible areas over short periods of time.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Forestry
Zhengnan Zhang, Tiejun Wang, Andrew K. Skidmore, Fuliang Cao, Guanghui She, Lin Cao
Summary: The diameter at breast height (DBH) is an important trait for studying plant ecology and biodiversity, as well as managing forests. Traditional ground-based approaches for measuring individual tree DBH over large areas are time-consuming and expensive. In this study, we propose an improved area-based approach using airborne LiDAR data to estimate plot-level DBH by utilizing the relationship between tree height and DBH. The results demonstrate the potential of using height-DBH relationships to improve the accuracy of estimating plot-level DBH from airborne LiDAR data.
Article
Multidisciplinary Sciences
Siyu Liu, Martin Brandt, Thomas Nord-Larsen, Jerome Chave, Florian Reiner, Nico Lang, Xiaoye Tong, Philippe Ciais, Christian Igel, Adrian Pascual, Juan Guerra-Hernandez, Sizhuo Li, Maurice Mugabowindekwe, Sassan Saatchi, Yuemin Yue, Zhengchao Chen, Rasmus Fensholt
Summary: This study used nanosatellite imagery to create maps of above-ground biomass of trees in Europe and quantified the contribution of urban and agricultural trees to national carbon stocks. The results showed that although urban and agricultural trees only accounted for 2% of the total tree biomass, there were significant variations between countries, and urban trees made a substantial contribution to national carbon stocks.
Article
Remote Sensing
Kirrilly Pfitzner, Renee Bartolo, Timothy Whiteside, David Loewensteiner, Andrew Esparon
Summary: The relationship between species phenology and spectral separability is important for determining the optimal remote sensing sampling period to maximize spectral separability of vegetation species. In this study, the researchers measured the in-situ hyperspectral response of various understorey species in tropical savannas and found that most species displayed a photosynthetic spectral response with increased greenness at the end of the wet season, gradually declining as vegetation dried out. These findings have implications for determining the ideal sampling period for measuring outdoor canopy reflectance of understorey species.
INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION
(2022)
Article
Anthropology
Jesse Casana, Severin Fowles, Lindsay M. Montgomery, Richard Mermejo, Carolin Ferwerda, Austin Chad Hill, Michael Adler
Summary: This study utilizes a new ultra-compact drone-based lidar system, alongside aerial thermal and visible light imaging, to document ancient agricultural landscapes in New Mexico. The results reveal extensive remains of terraces and stone-built field systems, providing new perspectives on past agricultural activities. Combining multiple drone-based remote sensing datasets with detailed surface surveys proves to be effective in archaeological landscape discovery and interpretation in forested regions.
JOURNAL OF ARCHAEOLOGICAL SCIENCE
(2023)
Article
Forestry
Noora Tienaho, Tuomas Yrttimaa, Ville Kankare, Mikko Vastaranta, Ville Luoma, Eija Honkavaara, Niko Koivumaki, Saija Huuskonen, Jari Hynynen, Markus Holopainen, Juha Hyyppa, Ninni Saarinen
Summary: The structural complexity of trees is important for ecological processes and ecosystem services. In this study, the fractal-based box dimension (D-b) was used to assess the structural complexity of Scots pine trees using point cloud data from terrestrial laser scanning (TLS) and aerial imagery from an unmanned aerial vehicle (UAV). The results showed significant differences between the D-b values measured by TLS and UAV, with UAV measurements being higher and having a wider range. The differences were explained by variations in point density, distribution, tree heights, and the number of boxes in the D-b method. Despite these differences, there was still a consistent correlation between TLS and UAV measurements, with a correlation coefficient of 75%.
Article
Plant Sciences
Farida Abubakari, Philip Nti Nkrumah, Denise R. Fernando, Peter D. Erskine, Antony van der Ent
Summary: This study found that wild M. ternifolia and M. integrifolia are strong Mn accumulators, and M. integrifolia and M. tetraphylla also exhibit high Mn accumulation under experimental conditions. The efficient translocation of Mn from roots to shoots was demonstrated in the studied species.
ENVIRONMENTAL AND EXPERIMENTAL BOTANY
(2022)
Article
Agronomy
Roger H. Tang, Peter D. Erskine, Philip Nti Nkrumah, Guillaume Echevarria, Antony van der Ent
Summary: Metallophytes are plants that can tolerate extreme metal concentrations in soil. A study on the Dugald River gossan in Australia found that there was no direct relationship between the occurrence of metallophytes and prevailing soil metal concentrations. Crotalaria novae-hollandiae was identified as a strong polymetallic indicator-type metallophyte that can accumulate high concentrations of metals in its leaves.
Article
Plant Sciences
Farida Abubakari, Philip Nti Nkrumah, Denise R. Fernando, Peter D. Erskine, Guillaume Echevarria, Antony van der Ent
Summary: This study is the first to investigate manganese accumulation and tissue-level distribution in Gossia bidwillii. It was found that wild G. bidwillii has a strong ability to hyperaccumulate manganese, and experimental plants also accumulated significant amounts of manganese. Laboratory-based micro-X-ray fluorescence analysis revealed that manganese is uniformly distributed in the leaves and petioles of wild G. bidwillii, while in the manganese-dosed plants, manganese was primarily concentrated at the leaf tips and laminae.
TROPICAL PLANT BIOLOGY
(2022)
Article
Forestry
Arian L. D. Paul, Sandrine Q. Isnard, Francis Brearley, Guillaume D. Echevarria, Alan J. M. Baker, Peter Erskine, Antony van der Ent
Summary: This study reveals the cycling of nutrients in ultramafic rain forests in New Caledonia. Most of the magnesium is found in the soil, while a portion of calcium and phosphorus, as well as the majority of potassium, is contained in the plant biomass. This study is essential for the restoration of rain forests in New Caledonia.
FOREST ECOLOGY AND MANAGEMENT
(2022)
Article
Agronomy
Antony van der Ent, Yohan Pillon, Bruno Fogliani, Vidiro Gei, Tanguy Jaffre, Peter D. Erskine, Guillaume Echevarria, Kathryn M. Spiers, Adrian L. D. Paul, Sandrine Isnard
Summary: The Cunoniaceae in New Caledonia have 91 endemic species that hyperaccumulate multiple metals, making them an ideal model system for studying the hyperaccumulation phenomenon. XRF scanning revealed differences in Mn and Ni accumulation in different species, with Pancheria reticulata showing Mn concentration in hypodermal cells and P. xaragurensis mainly accumulating Ni in and around the epidermis. This suggests different ecophysiological adaptations in these species.
Article
Ecology
Phillip B. McKenna, Alex M. Lechner, Lorna Hernandez Santin, Stuart Phinn, Peter D. Erskine
Summary: This paper evaluates the capability of remote sensing data for monitoring ecosystem restoration and proposes a combination of remote sensing with the ecological recovery wheel (ERW) for improved restoration outcomes.
RESTORATION ECOLOGY
(2023)
Article
Environmental Sciences
Justin Hughes, Cuan Petheram, Andrew Taylor, Matthias Raiber, Phil Davies, Shaun Levick
Summary: Hydrological investigation on small islands is challenging due to the physical environment and limited resources. Norfolk Island, as a typical small island in the South-west Pacific, has experienced water shortages, highlighting the lack of hydrological knowledge for informed decisions. Analysis of field measurements and data comparison reveals a decline in rainfall, increased potential evapo-transpiration, and changes in land cover, resulting in a significant decline in groundwater level and runoff.
Review
Ecology
Mitchel L. M. Rudge, Shaun R. Levick, Renee E. Bartolo, Peter D. Erskine
Summary: This article explores practical options for creating landscape-scale forest restoration targets that embrace spatial pattern. Hierarchy theory, satellite remote sensing, landscape pattern analysis, drone-based remote sensing, and spatial point pattern analysis are all useful tools for assessing and quantifying the spatial pattern of reference landscapes and informing forest restoration targets.
Article
Environmental Sciences
Andrew J. Harford, Renee E. Bartolo, Chris L. Humphrey, Jaylen D. Nicholson, Darren L. Richardson, David Rissik, Michelle Iles, Jeffrey M. Dambacher
Summary: This study utilizes qualitative mathematical modeling to conduct ecological risk assessments for both terrestrial and aquatic systems, providing support for the rehabilitation of the Ranger uranium mine. The results indicate that fire and weeds have significant impacts on the terrestrial system, while magnesium plays a crucial role in the aquatic system. Additionally, the qualitative modeling approach serves as a decision tool for identifying important subsystems in further research efforts.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2022)
Article
Geography, Physical
Yiqing Guo, Karel Mokany, Cindy Ong, Peyman Moghadam, Simon Ferrier, Shaun R. Levick
Summary: The diversity of terrestrial vascular plants plays a crucial role in maintaining ecosystem stability and productivity. This study evaluated the potential of using DESIS hyperspectral data to predict plant species richness in two different habitats in southeast Australia. The results showed that the DESIS data performed well in predicting plant species richness, with certain spectral regions being more important than others.
ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING
(2023)
Article
Ecology
Louise Terryn, Kim Calders, Markku Akerblom, Harm Bartholomeus, Mathias Disney, Shaun Levick, Niall Origo, Pasi Raumonen, Hans Verbeeck
Summary: Detailed 3D quantification of tree structure is crucial for understanding tree- and plot-level biophysical processes. Our ITSMe toolbox, which works with LiDAR tree point clouds and quantitative structure models, provides a robust framework for obtaining individual tree structural metrics from 3D data. It is open-source and aims to make the use of 3D data more straightforward and transparent for researchers interested in tree structure information.
METHODS IN ECOLOGY AND EVOLUTION
(2023)
Article
Environmental Sciences
Harm Bartholomeus, Kim Calders, Tim Whiteside, Louise Terryn, Sruthi M. Krishna Moorthy, Shaun R. Levick, Renee Bartolo, Hans Verbeeck
Summary: In vegetation monitoring, it is important to understand the changes caused by measurement setup and true representations of vegetation dynamics. This study examines the differences in derived forest metrics using three different UAV-LiDAR systems in a savanna woodland. The findings show that all three systems can accurately derive plot characteristics, but clear differences exist between metrics derived with different sensors, particularly in the lower parts of the canopy. It is crucial to be aware of these differences when comparing UAV-LiDAR data of forest areas through time.
Article
Biochemistry & Molecular Biology
Farida Abubakari, Denise R. Fernando, Philip Nti Nkrumah, Hugh H. Harris, Peter D. Erskine, Antony van der Ent
Summary: Macadamia integrifolia and M. tetraphylla, unlike M. ternifolia, are known for their edible nuts. This study investigates the distribution of manganese (Mn) and other plant nutrients in the tissues and cells of these three Macadamia species. The results show that Mn is primarily sequestered in the leaf and midrib palisade mesophyll cells of all three species, with Mn also present in leaf interveinal regions, root cortical cells, and phloem cells. The study provides new insights into Mn compartmentalization in these highly Mn-tolerant Macadamias and expands knowledge about the potentially toxic over-accumulation of an essential micronutrient, which can inform farming strategies for edible species.