This study employs LiDAR technology to calculate vegetation structural metrics that may be useful for assessing habitat quality and predicting the presence and abundance of structurally sensitive ...animal species. We compare outputs from two LiDAR platforms, an Unmanned Aerial Vehicle (RIEGL miniVUX-1UAV LiDAR; ULS) and a Terrestrial Laser Scanner (Topcon GLS2000; TLS) that we used to collect structural data from a critically endangered woodland ecosystem in SE Australia. This is also the site of a longterm restoration study and ongoing wildlife population monitoring. Despite better overall coverage by the ULS, the TLS provided considerably higher values for ground layer vegetation complexity and higher vegetation volume for the mid-story and canopy strata. We discuss the factors that may influence these observations and implications for using these sensors for habitat assessments.
In this paper we present a study on the estimation of the aboveground biomass in tropical forests at single tree level using airborne laser scanning (ALS) data. Individual tree crowns (ITCs) are ...firstly detected using a method based on an adaptive window that change its size according to tree height. The diameter at breast height (DBH) and the aboveground biomass (AGB) of each ITC then are predicted using standard allometric models. Lastly, the AGB values are aggregated at plot level, and compared with field measured values. The results show that it is possible to accurately predict the aboveground biomass of tropical forests at single tree level using ALS data.
Borneo contains some of the world's most biodiverse and carbon dense tropical forest, but this 750,000-km2 island has lost 62% of its old-growth forests within the last 40 years. Efforts to protect ...and restore the remaining forests of Borneo hinge on recognising the ecosystem services they provide, including their ability to store and sequester carbon. Airborne Laser Scanning (ALS) is a remote sensing technology that allows forest structural properties to be captured in great detail across vast geographic areas. In recent years ALS has been integrated into state-wide assessment of forest carbon in Neotropical and African regions, but not yet in Asia. For this to happen new regional models need to be developed for estimating carbon stocks from ALS in tropical Asia, as the forests of this region are structurally and compositionally distinct from those found elsewhere in the tropics. By combining ALS imagery with data from 173 permanent forest plots spanning the lowland rain forests of Sabah, on the island of Borneo, we develop a simple-yet-general model for estimating forest carbon stocks using ALS-derived canopy height and canopy cover as input metrics. An advanced feature of this new model is the propagation of uncertainty in both ALS- and ground-based data, allowing uncertainty in hectare-scale estimates of carbon stocks to be quantified robustly. We show that the model effectively captures variation in aboveground carbons stocks across extreme disturbance gradients spanning tall dipterocarp forests and heavily logged regions, and clearly outperforms existing ALS-based models calibrated for the tropics, as well as currently available satellite-derived products. Our model provides a simple, generalised and effective approach for mapping forest carbon stocks in Borneo, providing a key tool to support the protection and restoration of its tropical forests.
In mixed forests, interactions among species influence ecosystem functioning but environmental conditions also play an important role in shaping relationships between biodiversity and ecosystem ...functioning. In the context of climate change, the carbon and water balance in pure versus mixed forest stands may be differentially influenced by changing soil water availability. To test this hypothesis, we compared the influence of biodiversity on stand water use efficiency (WUES) in boreal forests between wet and dry years. We assessed the carbon isotope composition (delta C-13) of tree rings in Betula pendula, Pinus sylvestris, and Picea abies growing in pure versus mixed stands. In addition, we tested whether differences in WUES affected patterns of stand basal area increment (BAI(S)). No biodiversity effect was found for stand delta C-13 (delta C-13(S)) during the wet year. However, there was a significant increase in delta C-13(S) between the wet and the dry year and a significant effect of biodiversity on delta C-13(S) in the dry year. The increase in delta C-13(S) in mixed stands was associated with both selection and complementarity effects. Although BAI(S) decreased significantly in the dry year, changes in delta C-13(S) did not translate into variations in BAI(S) along the biodiversity gradient. Our results confirmed that the physiological response of boreal forest ecosystems to changing soil water conditions is influenced by species interactions and that during dry growing seasons, species interactions in mixed stands can lead to lower soil moisture availability. This illustrates that biodiversity effects can also be negative in mixed stands in the sense that soil resources can be more intensively exhausted. Overall, our results confirm that in boreal forests, the biodiversity-ecosystem functioning relationship depends on local environmental conditions.
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