المؤلفون: Julia Drewer, Ribka Sionita Tarigan, Lindsay F. Banin, Stella White, Elizabeth Raine, Sarah H. Luke, Edgar C. Turner, Ute Skiba, Nicholas J. Cowan, Jassica Prajna Dewi, Andreas Dwi Advento, Anak Agung Ketut Aryawan, Jean-Pierre Caliman, Pujianto

المصدر: Frontiers in Forests and Global Change, Vol 7 (2024)

مصطلحات موضوعية: nitrous oxide, methane, ecosystem respiration, mineral soil, Sumatra, Indonesia, Forestry, SD1-669.5, Environmental sciences, GE1-350

الوصف: Oil palm (OP) plantations have replaced large areas of forest in the tropical landscape of Southeast Asia and are major emitters of greenhouse gases (GHGs). To move towards more environmentally friendly plantation management, a hopeful approach is to implement strategies to increase vegetation complexity. These options include relaxed management of understory vegetation to increase complexity in productive plantations, passive restoration of forest areas around rivers by leaving mature oil palm during replanting, and active forest restoration along river margins with planting of forest trees. These practices have the potential to deliver a range of benefits such as soil protection, reduced erosion and sedimentation in rivers, pest control and support for biodiversity, but little is known about their impact on greenhouse gas fluxes. The aim of this study was to assess the impact of improved understory growth management and the use of riparian forestry on GHG fluxes in OP plantations, making use of two long-term experiments (the Biodiversity and Ecosystem Function in Tropical Agriculture Understory Vegetation (BEFTA UV) Project; the Riparian Ecosystem Restoration in Tropical Agriculture (RERTA) Project) in Riau Province, Sumatra, Indonesia. We measured nitrous oxide (N2O), methane (CH4) and ecosystem respiration (CO2) from mature OP sites with different levels of understory vegetation and different riparian buffer restoration treatments using the static chamber method. We used linear mixed effects models to test for treatment effects, whilst accounting for soil moisture and experimental design factors (time and space). The understory vegetation treatments (normal, reduced and enhanced complexity of understory) had no effect on N2O and CH4 flux. Regarding differences in ecosystem respiration, effects attributable to the understory vegetation treatments were not strong. For the riparian restoration treatments, the fixed effects variables in the models explained little variation in the fluxes of all GHGs. Therefore, given the proven benefits of more complex understory vegetation for supporting biodiversity and healthy ecosystem functioning, plus the potential for restored riparian buffers to support biodiversity and services and to reduce GHG emissions over time, our findings reinforce the concept that these features bring environmental benefits in OP landscapes, with no measurable effects on GHG emissions.

وصف الملف: electronic resource

العلاقة: https://www.frontiersin.org/articles/10.3389/ffgc.2024.1324475/fullTest; https://doaj.org/toc/2624-893XTest

الوصول الحر: https://doaj.org/article/ebdc571db4fb45a9a6844631f334ff07Test

المؤلفون: Jake Stone, Andreas Dwi Advento, Michael D. Pashkevich, Anak Agung Ketut Aryawan, Jean‐Pierre Caliman, Amelia S. C. Hood, William A. Foster, Mohammad Naim, Pujianto, Dedi Purnomo, Suhardi, Ribka Sionita Tarigan, Tuani Dzulfikar Siguga Rambe, Rudy Harto Widodo, Sarah H. Luke, Jake L. Snaddon, Edgar C. Turner

المصدر: Ecological Solutions and Evidence, Vol 4, Iss 4, Pp n/a-n/a (2023)

مصطلحات موضوعية: assassin bugs (Reduviidae), biological control agents, habitat heterogeneity, integrated pest management (IPM), oil palm agroecology, tropical agriculture, Environmental sciences, GE1-350, Ecology, QH540-549.5

الوصف: Abstract The expansion of oil palm agriculture across Southeast Asia has caused significant biodiversity losses, with the reduction in habitat heterogeneity that accompanies the conversion of forest to oil palm being a major contributing factor. However, owing to their long commercial lifespan, oil palm plantations can support relatively high levels of vegetation complexity compared to annual crops. There is therefore potential for the implementation of management strategies to increase vegetation complexity and associated within‐plantation habitat heterogeneity, enhancing species richness and associated ecosystem functioning within productive oil palm landscapes. This study focusses on two species of asassin bugs Cosmolestes picticeps and Sycanus dichotomus, which are important agents of pest control within oil palm systems. Using a Before‐After Control‐Impact experimental manipulation in Sumatra, Indonesia, we tested the effect of three alternative herbicide spraying regimes and associated vegetation complexity treatments on assassin bug numbers. Our treatments encompass a range of current understory vegetation management practices used in oil palm plantations and include removing vegetation only in areas key to harvesting (“Normal”), removing all understory vegetation (“Reduced”), and allowing native vegetation to regrow naturally (“Enhanced”). We assessed both the long‐term (18 months) and short‐term (within 2 weeks) effects of our treatments following herbicide spraying. Pre‐treatment, we found high numbers of assassin bugs of both species in all plots. Long‐term post‐treatment, the abundance of both C. picticeps and S. dichotomus declined in reduced understory plots, although this decline was only significant for C. picticeps (98%). In contrast, there were no significant differences in the post‐treatment abundance of either species in the short‐term. These results suggest that the long‐term decline in assassin bug abundance was likely to be caused by loss of vegetation, rather than any immediate effects of the herbicide spraying. Our findings have clear management implications as they demonstrate that maintaining vegetation in oil palm understories can benefit an important pest control agent.

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2688-8319Test

الوصول الحر: https://doaj.org/article/84276643542f4bdb9cccc12fe0d7ee56Test

المؤلفون: Valentine Joy Reiss-Woolever, Andreas Dwi Advento, Anak Agung Ketut Aryawan, Jean-Pierre Caliman, William A. Foster, Mohammad Naim, Pujianto, Dedi Purnomo, Soeprapto, Suhardi, Ribka Sionita Tarigan, Resti Wahyuningsih, Tuani Dzulfikar Siguga Rambe, Sudharto Ps, Rudy Harto Widodo, Sarah H. Luke, Jake L. Snaddon, Edgar C. Turner

المصدر: Frontiers in Forests and Global Change, Vol 6 (2023)

مصطلحات موضوعية: agricultural inputs, herbicides, invertebrate biodiversity, Lepidoptera, palm oil, sustainable agriculture, Forestry, SD1-669.5, Environmental sciences, GE1-350

الوصف: IntroductionThe cultivation of oil palm, from which palm oil, the world’s most widely traded vegetable oil, is processed, has had marked effects on ecosystems and native species across the tropics. While declines in biodiversity due to conversion to oil palm have been well recorded across plant and animal taxa, less work has been done to identify approaches to plantation management which will enable producers to satisfy growing global demand while limiting environmental damage.MethodsThrough a large-scale understory management experiment, we investigated the long- and short-term effects of varying vegetation management regimes on the abundance, richness, and diversity of day-flying Lepidoptera.ResultsOver the long-term, the lowest levels of vegetation complexity resulted in significantly lower Lepidoptera abundance, species richness and evenness. Less intensive understory clearing resulted in healthier communities, with limited differences between removal by herbicide application or chemical-free removal. Over the short-term, biodiversity was not directly affected by vegetation complexity, suggesting that manual removal of vegetation may be equally damaging to butterfly or moth communities as removal by intermediate levels of herbicide spraying.DiscussionThese findings substantiate calls to limit vegetation clearing and maintain habitat heterogeneity on both a local and landscape scale, while also suggesting that a hard “no-spray” guideline may not be the only option to support butterfly friendly plantations.

وصف الملف: electronic resource

العلاقة: https://www.frontiersin.org/articles/10.3389/ffgc.2023.1205744/fullTest; https://doaj.org/toc/2624-893XTest

الوصول الحر: https://doaj.org/article/3da2121a5ac14df288d5d30ca81584ffTest

المؤلفون: Michael D. Pashkevich, Dakota M. Spear, Andreas Dwi Advento, Jean-Pierre Caliman, William A. Foster, Sarah H. Luke, Mohammad Naim, Sudharto Ps, Jake L. Snaddon, Edgar C. Turner

المصدر: Basic and Applied Ecology, Vol 64, Iss , Pp 120-133 (2022)

مصطلحات موضوعية: Ecology, QH540-549.5

الوصف: Conversion of natural habitats to oil palm agriculture has caused declines in biodiversity and changes in ecosystem functions. To preserve biodiversity we must protect natural habitats, but once oil palm plantations are established, developing more-environmentally friendly management strategies could support higher levels of within-plantation biodiversity and boost the delivery of ecosystem services, possibly increasing oil palm productivity. In this study, we use a before-after control-impact (BACI) experiment to test whether three understory vegetation management strategies affect spider abundance, species richness, and species-level community composition in canopy and ground microhabitats in mature oil palm plantations. Our treatments encompassed the range of current management practices and included heavy applications of herbicides to eliminate all understory vegetation, maintaining some understory vegetation using business-as-usual herbicide applications, and enhancing understory vegetation by not applying any herbicides. We focussed on spiders, as they are both biologically and economically important in oil palm plantations, owing to their important pest control services. We identified more than 1000 spiders, representing 20 families and 83 morphospecies. The treatments did not affect any aspects of spider biodiversity, although the abundance and species richness of canopy-dwelling spiders changed between pre- and post-treatment sample periods, independent of treatment. Our findings indicate that differences in understory vegetation management practices do not affect spiders, or the pest management services that they provide, in mature oil palm plantations. As such, more extreme changes in management would probably be required to enhance spider biodiversity in oil palm plantations in the long-term. Further studies are needed to determine the practicalities of such approaches, to assess how changes in vegetation management practices affect spiders in additional microhabitats, and how the impacts of such approaches vary across the 20–30 year oil palm commercial life cycle.

وصف الملف: electronic resource

العلاقة: http://www.sciencedirect.com/science/article/pii/S1439179122000718Test; https://doaj.org/toc/1439-1791Test

الوصول الحر: https://doaj.org/article/79ca49bd7b784d2a8a0b53dd6adbe9f0Test

المؤلفون: Andreas Dwi Advento, Kalsum Yusah, Hasber Salim, Mohammad Naim, Jean-Pierre Caliman, Tom Fayle

المصدر: Biodiversity Data Journal, Vol 10, Iss , Pp 1-12 (2022)

مصطلحات موضوعية: Formicidae, parasitism, biocontrol, bagworm, Riau, Biology (General), QH301-705.5

الوصف: Asian weaver ants (Oecophylla smaragdina) are an important biocontrol agent in agricultural habitats. We conducted surveys in oil palm plantations in Riau, Indonesia for an obligate myrmecophilous butterfly larvae, Liphyra brassolis (Lepidoptera, Lycaenidae), that is known to consume weaver ant larvae in other habitat types. We found L. brassolis larvae in five of the twenty nests surveyed, with larval presence not being related to weaver ant nest size. We also observed L. brassolis larvae in a weaver ant mass rearing facility. This is the first report of L. brassolis from oil palm plantations and may have implications for the use of weaver ants as biological control agents.

وصف الملف: electronic resource

العلاقة: https://bdj.pensoft.net/article/83842/download/pdfTest/; https://bdj.pensoft.net/article/83842/download/xmlTest/; https://bdj.pensoft.net/article/83842Test/; https://doaj.org/toc/1314-2828Test

الوصول الحر: https://doaj.org/article/e700e69ba67043bc8206b0078c185eefTest

المؤلفون: Adham Ashton‐Butt, Simon Willcock, Dedi Purnomo, Suhardi, Anak A. K. Aryawan, Resti Wahyuningsih, Mohammad Naim, Guy M. Poppy, Jean‐Pierre Caliman, Kelvin S.‐H. Peh, Jake L. Snaddon

المصدر: Ecology and Evolution, Vol 9, Iss 11, Pp 6433-6443 (2019)

مصطلحات موضوعية: agriculture, belowground, ecosystem function, invertebrate, Macrofauna, soil, Ecology, QH540-549.5

الوصف: Abstract Conversion of forest to oil palm plantations results in a significant loss of biodiversity. Despite this, first‐cycle oil palm plantations can sustain relatively high biodiversity compared to other crops. However, the long‐term effects of oil palm agriculture on flora and fauna are unknown. Oil palm has a 25‐year commercial lifespan before it must be replanted, due to reduced productivity and difficulty of harvesting. Loss of the complex vegetation structure of oil palm plantations during the replanting process will likely have impacts on the ecosystem at a local and landscape scale. However, the effect of replanting on biodiversity is poorly understood. Here, we investigate the effects of replanting oil palm on soil macrofauna communities. We assessed ordinal richness, abundance, and community composition of soil macrofauna in first‐ (25‐ to 27‐year‐old) and second‐cycle oil palm (freshly cleared, 1‐year‐old, 3‐year‐old, and 7‐year‐old mature). Macrofauna abundance and richness drastically declined immediately after replanting. Macrofauna richness showed some recovery 7 years after replanting, but was still 19% lower than first‐cycle oil palm. Macrofauna abundance recovered to similar levels to that of first‐cycle oil palm plantations, 1 year after replanting. This was mainly due to high ant abundance, possibly due to the increased understory vegetation as herbicides are not used at this age. However, there were subsequent declines in macrofauna abundance 3 and 7 years after replanting, resulting in a 59% drop in macrofauna abundance compared to first‐cycle levels. Furthermore, soil macrofauna community composition in all ages of second‐cycle oil palm was different to first‐cycle plantations, with decomposers suffering particular declines. After considerable biodiversity loss due to forest conversion for oil palm, belowground invertebrate communities suffer a second wave of biodiversity loss due to replanting. This is likely to have serious implications for soil invertebrate diversity and agricultural sustainability in oil palm landscapes, due to the vital ecosystem functions that soil macrofauna provide.

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2045-7758Test

الوصول الحر: https://doaj.org/article/e8a4af02d928445882a59f335b8f058eTest

المؤلفون: Divo Dharma Silalahi, Habshah Midi, Jayanthi Arasan, Mohd Shafie Mustafa, Jean-Pierre Caliman

المصدر: Heliyon, Vol 6, Iss 1, Pp e03176- (2020)

مصطلحات موضوعية: Analytical chemistry, Near infrared, Spectral data, Partial least squares, Diagnostic robust generalized potential, Nonlinear, Science (General), Q1-390, Social sciences (General), H1-99

الوصف: In practice, the collected spectra are very often composes of complex overtone and many overlapping peaks which may lead to misinterpretation because of its significant nonlinear characteristics. Using linear solution might not be appropriate. In addition, with a high-dimension of dataset due to large number of observations and data points the classical multiple regressions will neglect to fit. These complexities commonly will impact to multicollinearity problem, furthermore the risk of contamination of multiple outliers and high leverage points also increases. To address these problems, a new method called Kernel Partial Diagnostic Robust Potential (KPDRGP) is introduced. The method allows the nonlinear solution which maps nonlinearly the original input X matrix into higher dimensional feature mapping with corresponds to the Reproducing Kernel Hilbert Spaces (RKHS). In dimensional reduction, the method replaces the dot products calculation of elements in the mapped data to a nonlinear function in the original input space. To prevent the contamination of the multiple outlier and high leverage points the robust procedure using Diagnostic Robust Generalized Potentials (DRGP) algorithm was used. The results verified that using the simulation and real data, the proposed KPDRGP method was superior to the methods in the class of non-kernel and some other robust methods with kernel solution.

وصف الملف: electronic resource

العلاقة: http://www.sciencedirect.com/science/article/pii/S2405844020300219Test; https://doaj.org/toc/2405-8440Test

الوصول الحر: https://doaj.org/article/9fd48ad127224cacb7c9e439e1dd4384Test

المؤلفون: Sarah H. Luke, Andreas Dwi Advento, Anak Agung Ketut Aryawan, Dwi Nugroho Adhy, Adham Ashton-Butt, Holly Barclay, Jassica Prajna Dewi, Julia Drewer, Alex J. Dumbrell, Edi, Amy E. Eycott, Martina F. Harianja, Julie K. Hinsch, Amelia S. C. Hood, Candra Kurniawan, David J. Kurz, Darren J. Mann, Kirsty J. Matthews Nicholass, Mohammad Naim, Michael D. Pashkevich, Graham W. Prescott, Sudharto Ps, Pujianto, Dedi Purnomo, Rizky Rajabillah Purwoko, Syafrisar Putra, T. Dzulfikar S. Rambe, Soeprapto, Dakota M. Spear, Suhardi, David J. X. Tan, Hsiao-Hang Tao, Ribka Sionita Tarigan, Resti Wahyuningsih, Helen S. Waters, Rudi Harto Widodo, Whendy, Christopher R. Woodham, Jean-Pierre Caliman, Eleanor M. Slade, Jake L. Snaddon, William A. Foster, Edgar C. Turner

المصدر: Frontiers in Forests and Global Change, Vol 2 (2020)

مصطلحات موضوعية: biodiversity, habitat heterogeneity, palm oil, plantation management, sustainability, tropical agriculture, Forestry, SD1-669.5, Environmental sciences, GE1-350

الوصف: Conversion of tropical forest to agriculture results in reduced habitat heterogeneity, and associated declines in biodiversity and ecosystem functions. Management strategies to increase biodiversity in agricultural landscapes have therefore often focused on increasing habitat complexity; however, the large-scale, long-term ecological experiments that are needed to test the effects of these strategies are rare in tropical systems. Oil palm (Elaeis guineensis Jacq.)—one of the most widespread and important tropical crops—offers substantial potential for developing wildlife-friendly management strategies because of its long rotation cycles and tree-like structure. Although there is awareness of the need to increase sustainability, practical options for how best to manage oil palm plantations, for benefits to both the environment and crop productivity, have received little research attention. In this paper we introduce the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Programme: a long-term research collaboration between academia and industry in Sumatra, Indonesia. The BEFTA Programme aims to better understand the oil palm agroecosystem and test sustainability strategies. We hypothesise that adjustments to oil palm management could increase structural complexity, stabilise microclimate, and reduce reliance on chemical inputs, thereby helping to improve levels of biodiversity and ecosystem functions. The Programme has established four major components: (1) assessing variability within the plantation under business-as-usual conditions; (2) the BEFTA Understory Vegetation Project, which tests the effects of varying herbicide regimes; (3) the Riparian Ecosystem Restoration in Tropical Agriculture (RERTA) Project, which tests strategies for restoring riparian habitat; and (4) support for additional collaborative projects within the Programme landscape. Across all projects, we are measuring environmental conditions, biodiversity, and ecosystem functions. We also measure oil palm yield and production costs, in order to assess whether suggested sustainability strategies are feasible from an agronomic perspective. Early results show that oil palm plantation habitat is more variable than might be expected from a monoculture crop, and that everyday vegetation management decisions have significant impacts on habitat structure. The BEFTA Programme highlights the value of large-scale collaborative projects for understanding tropical agricultural systems, and offers a highly valuable experimental set-up for improving our understanding of practices to manage oil palm more sustainably.

وصف الملف: electronic resource

العلاقة: https://www.frontiersin.org/article/10.3389/ffgc.2019.00075/fullTest; https://doaj.org/toc/2624-893XTest

الوصول الحر: https://doaj.org/article/b8e971db501a48b786367b13a2d52efdTest

المؤلفون: Amelia S. C. Hood, A. Agung K. Aryawan, Andreas D. Advento, Dedi Purnomo, Resti Wahyuningsih, Sarah H. Luke, Sudharto Ps, Jake L. Snaddon, William A. Foster, Jean-Pierre Caliman, Edgar C. Turner, Mohammad Naim

المصدر: Frontiers in Forests and Global Change, Vol 2 (2019)

مصطلحات موضوعية: oil palm, Leopard Cat, Rattus, habitat heterogeneity, habitat complexity, understory vegetation, Forestry, SD1-669.5, Environmental sciences, GE1-350

الوصف: The expansion of oil palm (Elaeis guineensis) plantations is a primary cause of land-use change and biodiversity loss in Southeast Asia. This has led to an increasing demand for the development of more sustainable agricultural management practices in plantations, such as Integrated Pest Management. Although populations of carnivorous mammals show declines when forest is converted to oil palm, some species, such as Leopard Cats (Prionailurus bengalensis) have been found to persist. They are often encouraged by plantation managers for their conservation value, and as agents of pest control to manage rat populations. Despite this, little is known about whether they reduce pest rat numbers, or whether plantation management affects how they use the oil palm habitat. This study was based at the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Programme in mature oil palm plantations in Riau, Sumatra, where there are three management strategies altering understory vegetation structure. We quantified Leopard Cat activity, invasive rat abundance and rat damage using camera traps, live traps, and visual estimates, respectively. We collected data over a 4-year period, before and after the management strategies were applied. We recorded three species of wild mammals (Leopard Cats, Common Palm Civets, and Wild Pig) within the plantations, of which Leopard Cats made up 82% of the total number of observations. We found that Leopard Cat habitat use was higher with increased understory vegetation, but that there was no effect of the vegetation treatments on rat abundance or rat damage. There was also a trend for reduced rat abundance with increased Leopard Cat activity. These results show that management practices can significantly affect Leopard Cat habitat use, with potential benefits for pest control. They also highlight the value of large-scale long-term manipulative experiments for developing more sustainable management practices in oil palm.

وصف الملف: electronic resource

العلاقة: https://www.frontiersin.org/article/10.3389/ffgc.2019.00051/fullTest; https://doaj.org/toc/2624-893XTest

الوصول الحر: https://doaj.org/article/ee0f62f50ef54c4caee5ebe272698607Test

المؤلفون: Divo Dharma Silalahi, Habshah Midi, Jayanthi Arasan, Mohd Shafie Mustafa, Jean-Pierre Caliman

المصدر: Symmetry, Vol 13, Iss 4, p 547 (2021)

مصطلحات موضوعية: partial least square regression, outliers, high leverage points, GM6 estimator, robust, nonlinear, Mathematics, QA1-939

الوصف: Multivariate statistical analysis such as partial least square regression (PLSR) is the common data processing technique used to handle high-dimensional data space on near-infrared (NIR) spectral datasets. The PLSR is useful to tackle the multicollinearity and heteroscedasticity problem that can be commonly found in such data space. With the problem of the nonlinear structure in the original input space, the use of the classical PLSR model might not be appropriate. In addition, the contamination of multiple outliers and high leverage points (HLPs) in the dataset could further damage the model. Generally, HLPs contain both good leverage points (GLPs) and bad leverage points (BLPs); therefore, in this case, removing the BLPs seems relevant since it has a significant impact on the parameter estimates and can slow down the convergence process. On the other hand, the GLPs provide a good efficiency in the model calibration process; thus, they should not be eliminated. In this study, robust alternatives to the existing kernel partial least square (KPLS) regression, which are called the kernel partial robust GM6-estimator (KPRGM6) regression and the kernel partial robust modified GM6-estimator (KPRMGM6) regression are introduced. The nonlinear solution on PLSR was handled through kernel-based learning by nonlinearly projecting the original input data matrix into a high-dimensional feature mapping that corresponded to the reproducing kernel Hilbert spaces (RKHS). To increase the robustness, the improvements on GM6 estimators are presented with the nonlinear PLSR. Based on the investigation using several artificial dataset scenarios from Monte Carlo simulations and two sets from the near-infrared (NIR) spectral dataset, the proposed robust KPRMGM6 is found to be superior to the robust KPRGM6 and non-robust KPLS.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/2073-8994/13/4/547Test; https://doaj.org/toc/2073-8994Test

الوصول الحر: https://doaj.org/article/d783c89a6c3d411b94ab1d55b55ef663Test