Large-Scale Mapping of Tree-Community Composition as a Surrogate of Forest Degradation in Bornean Tropical Rain Forests

Abstract

Assessment of the progress of the Aichi Biodiversity Targets set by the Convention on Biological Diversity (CBD) and the safeguarding of ecosystems from the perverse negative impacts caused by Reducing Emissions from Deforestation and Forest Degradation Plus (REDD+) requires the development of spatiotemporally robust and sensitive indicators of biodiversity and ecosystem health. Recently, it has been proposed that tree-community composition based on count-plot surveys could serve as a robust, sensitive, and cost-effective indicator for forest intactness in Bornean logged-over rain forests. In this study, we developed an algorithm to map tree-community composition across the entire landscape based on Landsat imagery. We targeted six forest management units (FMUs), each of which ranged from 50,000 to 100,000 ha in area, covering a broad geographic range spanning the most area of Borneo. Approximately fifty 20 m-radius circular plots were established in each FMU, and the differences in tree-community composition at a genus level among plots were examined for trees with diameter at breast height ≥10 cm using an ordination with non-metric multidimensional scaling (nMDS). Subsequently, we developed a linear regression model based on Landsat metrics (e.g., reflectance value, vegetation indices and textures) to explain the nMDS axis-1 scores of the plots, and extrapolated the model to the landscape to establish a tree-community composition map in each FMU. The adjusted R 2 values based on a cross-validation approach between the predicted and observed nMDS axis-1 scores indicated a close correlation, ranging from 0.54 to 0.69. Histograms of the frequency distributions of extrapolated nMDS axis-1 scores were derived from each map and used to quantitatively diagnose the forest intactness of the FMUs. Our study indicated that tree-community composition, which was reported as a robust indicator of forest intactness, could be mapped at a landscape level to quantitatively assess the spatial patterns of intactness in Bornean rain forests. Our approach can be used for large-scale assessments of tree diversity and forest intactness to monitor both the progress of Aichi Biodiversity Targets and the effectiveness of REDD+ biodiversity safeguards in production forests in the tropics.

Effects of Student-Induced Trampling on Aquatic Macroinvertebrates in Agricultural Headwater Streams

“…Differences in NMS site scores among days and riffle types were then quantified with linear mixed effect model analyses. This two-step analytical approach is an indirect gradient analysis where ordination is conducted only with community data and the relationships of taxa composition with habitat variables or different habitat categories are then determined with additional statistical tests [40][41][42]. Additionally, we calculated three hydrologic variables (mean wetted width, mean water depth, mean water velocity) from each riffle on each sampling day.…”

Biodiversity Observation for Land and Ecosystem Health (BOLEH): A Robust Method to Evaluate the Management Impacts on the Bundle of Carbon and Biodiversity Ecosystem Services in Tropical Production Forests

“…These two ecosystem services, among others, may be relatively easily incorporated into ecosystem-services certification because stakeholder adaptability is high for these services [10]. Our method "biodiversity observation for land and ecosystem health (BOLEH)" was developed primarily for evaluating forest intactness using a metric of tree community composition in logged-over tropical rain forests [21][22][23]: either species or genus composition could be used in this method. Earlier studies indicated that the use of genus composition was statistically equally reliable as species composition, and yet could reduce identification cost [21][22][23].…”

“…Our method "biodiversity observation for land and ecosystem health (BOLEH)" was developed primarily for evaluating forest intactness using a metric of tree community composition in logged-over tropical rain forests [21][22][23]: either species or genus composition could be used in this method. Earlier studies indicated that the use of genus composition was statistically equally reliable as species composition, and yet could reduce identification cost [21][22][23]. This approach is directly relevant to the FSC ecosystem-services certification because the following generic indicator for biodiversity conservation can be evaluated with our BOLEH:…”

Biodiversity in Locally Managed Lands

“…Fujiki et al [9] describe a method for predicting tree community composition, an indicator of forest intactness that could be used to monitor progress towards the achievement of the Aichi targets. It might also be used to monitor the effects of different management practices at a more local level.…”