2025 |
Dröge, Saskia; Jusrin, Muhammad J M; Verbist, Bruno; Prasetyo, Lilik B; Maertens, Miet; Muys, Bart No effect of Rainforest Alliance cocoa certification on shade cover and bird species richness in Sulawesi, Indonesia Journal Article In: Journal of Nature Conservation, vol. 84, iss. March 2025, no. 126849, 2025. Abstract | Links | BibTeX | Tags: agroforestry, species richness @article{nokey,Voluntary Sustainability Standards (VSS) and certification are promoted to enhance sustainable agricultural practices, but environmental outcomes of cocoa certification remain understudied. We selected 31 Rainforest Alliance (RA) certified and 31 non-certified cocoa plantations in Luwu Timur, Sulawesi, Indonesia, from a previous socioeconomic survey and assessed vegetation structure, soil fertility, as well as bird species richness. Using Wilcoxon Rank Sum tests, GLMMs and NMDS, we did not find certified plantations to have a higher shade tree diversity, shade tree basal area, and soil fertility. Bird species richness was significantly higher in certified plantations (p = 0.03), but the observed effect on bird species richness became statistically insignificant after controlling for elevation and plantation age in the GLMM. Current RA shade criteria are low, and potentially not sufficiently enforced, limiting RA potential to enhance biodiversity habitat. Certified farmers more frequently used improved farming techniques and received training; hence, certification might provide socioeconomic benefits to farmers while we found environmental outcomes of certification to be limited. Further research is needed to draw robust conclusions on VSS potential to enhance sustainable agriculture. |
2024 |
Dröge, Saskia; Prasetyo, Lilik B; Muys, Bart Acoustic indices as proxies for biodiversity in certified and non-certified cocoa plantations in Indonesia Bachelor Thesis 2024. Abstract | Links | BibTeX | Tags: acoustic, agroforestry @bachelorthesis{nokey,Acoustic indices allow time efficient analysis of large acoustic datasets obtained from passive acoustic monitoring, but results regarding their effectiveness in assessing biodiversity are inconsistent. We evaluated the efficacy of six acoustic indices (ACI, ADI, AEI, H, BI, NDSI) for studying bird and structural diversity in 51 cocoa plantations, 24 of which were certified by Rainforest Alliance, in Luwu Timur, Sulawesi, Indonesia. We used linear models to assess the correlation of index values with bird species richness, and linear mixed models to test the influence of canopy closure, shade tree basal area, distance to primary forest and tree cover in a 200-m buffer on index values. Bird species richness was positively correlated with BI (p = 0.02) and negatively with H (p = 0.03), yet predictive power was low (R2 = 0.10 and 0.09, respectively). Acoustic indices did not differ significantly for certified cocoa plantations. Tree cover within the 200-m buffer moderately well predicted ACI values (marginal R2 = 0.37) while for the other indices effect sizes were low or correlations were not significant. Comparing our results to other studies, acoustic indices may reflect biodiversity across land uses, but were of limited value for tracking subtle differences in cocoa plantations in Sulawesi. Future studies may include more land uses (i.e. rice paddies, secondary forest, oil palm) as well as more taxa (i.e. insects). More research is needed on the comparability of acoustic indices, as we found them to be influenced by recording equipment and calculation settings. |
Dröge, Saskia; Bemelmans, Janne; Depoorter, Charline; Jusrin, Muhammad J M; Marx, Axel; Verbist, Brono; Prasetyo, Lilik B; Maertens, Miet; Muys, Bart From chocolate to palm oil: The future of Indonesia’s cocoa plantations Journal Article In: Ambio, vol. 54, pp. 151-161, 2024. Abstract | Links | BibTeX | Tags: agroforestry @article{nokey,Indonesia is the world’s third largest cocoa producer, but production is decreasing since 2011. We revisited cocoa farmers for an environmental assessment in Luwu Timur, Sulawesi, 7 months after a socio-economic survey on cocoa certification outcomes and observed many cocoa plantations being converted into oil palm and maize. Including our field data as well as secondary data on commodity prices and yields, we outline reasons for cocoa conversion, potential consequences for biodiversity, and assess the future outlook for the Indonesian cocoa sector. Low cocoa productivity, volatile cocoa prices and higher revenue for oil palm, among others, drive land-use change. If shade trees are cut during cocoa conversion, it may have negative implications for biodiversity. Solutions to low soil fertility, omnipresent pests and diseases, and stable producer prices are needed to increase profitability of cocoa and prevent conversion of cocoa agroforests to oil palm monocultures. |
2019 |
Rudianto, Yoga; Prasetyo, Lilik B; Setiawan, Yudi; Hudjimartsu, Sahid A Canopy cover estimation of agroforestry based on airborne LiDAR and Landsat 8 OLI Conference vol. 11372, SPIE, 2019. Abstract | Links | BibTeX | Tags: agroforestry, canopy cover, Landsat, LiDAR @conference{Rudianto2019,Agroforestry/mixed gardens is a land management system that combines agricultural, livestock production with tree to obtain various products in a sustainable manner so as to increase social, economic and environmental benefits This system can be a form of mitigation and adaptation to global climate change, especially in areas with high population densities, but with less agricultural labor, such as in urban fringe area. Based on the formal definition of forests from the Indonesian Ministry of Environment and Forestry of Indonesia based on canopy cover, agroforestry might be considered as forest, whereas the canopy cover >30%. The research aim to estimate canopy cover base on integration of Lidar and Landsat 8 OLI of agroforestry in the Cidanau watershed. The most suitable equation model is an exponential equation (FRCI = 22.928e (-80.439 * 'RED')), however, some underestimation in high canopy cover ( >70%) and underestimation in low canopy cover (< 60%) should be anticipated. The result showed that agroforestry in some location have canopy cover greater than 30% and therefore it can be considered as a forest. |
Khairiah, Rahmi Nur; Prasetyo, Lilik B; Setiawan, Yudi Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., 2019. Abstract | Links | BibTeX | Tags: agroforestry, CidanauLandsat, hemispherical photos @conference{Khairiah2019,The Cidanau watershed is the only watershed in Indonesia that implements Payment for Environmental Services (PES) for farmers who can maintain tree/stand density of 500 trees/hectare on their land. Payments are made upon the verification on the field by the project supervisor. This method requires a lot of time and costly, so it is necessary to build more efficient indirect methods, including using satellite imagery or camera data. The aim of this study is to understand Landsat OLI 8 and hemispherical photo can estimate tree density in the farmer’s agroforestry stand. To obtain tree density, the number of trees with diameter more than 10 cm in 50 plots (50 m x 50 m) were counted. Some predictor variables were utilized, such as Leaf Area Index (LAI) based on hemispherical photos, Normalized Difference Vegetation Index (NDVI), Forest Cover Density (FCD), as well as NDVI and FCD which were enhanced with topographic correction. The imagery used was Landsat 8 OLI acquired on July 5, 2015, with Path/Row 123/64. The relationship between tree density and predictor variables was done using linear regression analysis. Prior to regression analysis, normality (Kolmogorov Smirnov/K-S), heteroscedasticity (Glejser test) and auto correlation (Durbin Watson) test were performed. The results of the analysis showed that tree density was estimated better with hemispherical photos-based LAI, with determination coefficient of 80.6%. Meanwhile, estimation using NDVI and FCD has lower determination coefficient. Even though, the use of topographic correction had been able to increase the determination coefficient of the regression relationship between tree density and FCD, from 4.64% to 35.18%. |
2025 |
No effect of Rainforest Alliance cocoa certification on shade cover and bird species richness in Sulawesi, Indonesia Journal Article In: Journal of Nature Conservation, vol. 84, iss. March 2025, no. 126849, 2025. |
2024 |
Acoustic indices as proxies for biodiversity in certified and non-certified cocoa plantations in Indonesia Bachelor Thesis 2024. |
From chocolate to palm oil: The future of Indonesia’s cocoa plantations Journal Article In: Ambio, vol. 54, pp. 151-161, 2024. |
2019 |
Canopy cover estimation of agroforestry based on airborne LiDAR and Landsat 8 OLI Conference vol. 11372, SPIE, 2019. |
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., 2019. |
