Dataverse World Agroforestry (ICRAF)
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Replication data for: Predicting geographic distribution and habitat suitability due to climate change of selected threatened forest tree species in the Philippines
No full textClimate change is projected to alter the geographic distribution of forest ecosystems. This study aimed to evaluate the consequences of climate change on geographical distributions and habitat suitability of 14 threatened forest tree species in the Philippines. Based on the principle of maximum entropy, it utilized a machine algorithm called Maxent to estimate a target probability distribution and habitat suitability of the selected species. Threatened forest tree species occurrence records and sets of biophysical and bioclimatic variables were inputted to Maxent program to predict current and future distribution of the species. The Maxent models of the threatened species were evaluated using Receiver Operating Characteristics Area Under Curve (ROC AUC) and True Skill Statistics
(TSS) tests which revealed that the models generated were better than random. The Maxent models ROC AUC values of the 14 species range from 0.70 to 0.972 which is higher than 0.5 of a null model. Based on TSS criteria, Maxent models performed good in two species, very good in ten species, and excellent in two species. Seven species (Afzelia rhomboidea; Koordersiodendron pinnatum; Mangifera altissima; Shorea contorta; Shorea palosapis; Shorea polysperma; Vitex parviflora) were found to likely benefit from future climate due to the potential increase in their suitable habitat while the other seven species (Agathis philippinensis; Celtis luzonica; Dipterocarpus grandiflorus; Shorea guiso; Shorea negrosensis; Toona calantas; Vatica mangachapoi) will likely experience decline in their suitable habitat. This study provided an initial understanding on how the distribution of threatened forest trees will be affected by climate change in the Philippines. The generated species distribution models and habitat suitability maps could be used as basis in formulating appropriate science-based adaptation policies, strategies and measures that could enhance the resilience of those threatened forest tree species and their natural ecosystems to current and future climate
Replication data for: Quantification of total element concentrations in soils using total X-ray fluorescence spectroscopy (TXRF)
No full textTotal X-ray fluorescence spectroscopy (TXRF) determines concentrations of major and trace elements in mul- tiple media. We developed and tested a method for the use of TXRF for direct quantification of total element concentrations in soils using an S2 PICOFOX
TM spectrometer (Bruker AXS Microanalysis GmbH, Germany). We selected 15 contrasting soil samples from across sub-Saharan Africa for element analysis to calibrate the instrument against concentrations determined using the inductively coupled plasma-mass spectroscopy (ICP-MS) standard method. A consistent underestimation of element concentrations using TXRF compared to ICP-MS reference analysis occurred, indicating that spectrometer recalibration was required. Single-element recalibrat
ion improved the TXRF spectrometer's sensitivity curve. Subsequent analysis revealed that TXRF determined total element concentrations of Al, K, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Ga accurately (model effi- cacy/slope close to 1:1 line, an
d R2 > 0.80) over a wide range of soil samples. Other elements that could be estimated with an acceptable precision (R2 > 0.60) compared with ICP-MS although generally somewhat under- or overestimated were P, Ca, As, Rb, Sr, Y, Pr, Ta and Pb. Even after recalibration, compared to ICP-MS the TXRF spectrometer produced underestimations for elements Na, Mg, Ba, Ce, Hf, La, Nd, W and Sm and over- estimations for elements Bi, Tl and Zr. We validated the degree of accuracy of th
e TXRF analytical method after recalibration using an independent set of 20 soil samples. We also tested the accuracy of the analysis using 2 multi-element standards as well as the method repeatability on replicate samples. The resulting total element concentration repeatability for all elements analyzed were within 10% coefficient of variability after the instru- ment recalibration except for Cd and Tl. Our findings demonstrate that TXRF could be used as a rapid screening tool for total element concentrations in soils assuming that sufficient calibration measures are followed
Replication data for: Flowering phenology of tree rhododendron along an elevation gradient in two sites in the Eastern Himalayas
No full textRhododendron arboreum Sm. is one of the most important components of the ecosystem as different individuals tend to bloom from early spring to early summer, maintaining pollinator populations with their profuse flowering over a wide variety of habitats in the temperate to subalpine regions. As many other organisms depend on the R. arboreum, its phenology is very important to study for knowing ecosystem and a
ffect of changing environment on phenological events of this species. In this paper relation of flowering phenology with various environmental parameters was studied to show effect of chosen variables on the flowering phenology of R. arboreum in two sites in Eastern Himalayan region
Replication data for: Effect of elevation and latitude on spring phenology of Rhododendron at Kanchenjunga Conservation Area, East Nepal
No full textIn the mountains, it is elevation gradients that govern the change in temperature. Generally, temperature in mountainous regions decreases with increasing elevation at a lapse rate of about 0.6°C every 100m. With a lapse rate of 0.6°C / 100 m of elevation, a plant population spread over 500 m of elevation range will experience mean temperature differences of c. 3°C. In this paper effect of elevation on spring phenology of R. arboreum spread over 600 m in steep mountain slopes was discussed
Return on Investment of RWH technologies in dryland areas of Eastern region of Kenya
No full textThe research study evaluated the effectiveness of rainwater harvesting technologies in Eastern Kenya through identifying conditions under which these technologies provide economic opportunities for smallholder farmers in the dryland areas of Eastern Kenya. Key variables in the study were: RWH technologies being used; Household sources of income; educational background of household members. Data collection was done through household survey questionnaires. The overall goal of this research was to improve the on distribution of rainwater harvesting technologies, and to increase the amount of financing going to rainwater harvesting from banks, micro finance institutions, non-profit organizations, and government agencies
Replication data for: Will funding to Reduce Emissions from Deforestation and (forest) Degradation (REDD+) stop conversion of peat swamps to oil palm in orangutan habitat in Tripa in Aceh, Indonesia?
No full textTripa is the last remaining peat-swamp forest that harbours a poten
tially viable Sumatran orangutan (Pongo abelii) sub-population in a formally but not effectively protected area. It appears to be a simple showcase where current efforts to financially support reducing emissions from deforestation and forest degradation (REDD+) converge with biodiversity and social co-benefits. In practice, however, the situation is more complex. REDD+ efforts interact with global palm oil trade and regulatory approaches (the moratorium) to achieve national goals for emissions reduction under umbrella of nationally appropriate mitigation actions (NAMA). To contextualize this debate, we assessed (i) land-use history and formal basis of palm-oil companies' rights; (ii) carbon (C) stocks, historical emission levels and potential emissions that can be avoided; (iii) economic benefits of land-use options and opportunity costs of avoiding emissions; (iv) biodiversity and environmental services; and (v) alternative options for "high C stock development" and employment generation. Natural forest cover declined (54 % in 1995, 18 % in 2009) while oil palm increased 4 - 39 %. Aboveground C stocks decreased from 148 Mg ha -1 in 1990 to 61 Mg ha-1 in 2009, leading to average annual emissions of 14.5 Mg (carbon dioxide) CO2e ha -1 year-1. While 41 % of these emissions yield less than American Dollar (USD) 5 of current economic benefits per Mg CO2e emitted and might be compensated by REDD+, nearly all new emissions derive from a breach of existing laws, regulations and voluntary palm-oil standards. Substantial investment in alternative employment is needed, rather than carbon payments per se, to support livelihoods in a low carbon emissions econom
Replication data for: Effects of transformation processes on plant species richness and diversity in homegardens of the Nuba Mountains, Sudan
No full textTraditional homegardens (HGs) are considered to harbor high levels of plant diversity and have been therefore characterized as sustainable agro-ecosystems suitable for on-farm (incl. circa situm) conservation of plant genetic resources. While the functional structure of traditional HGs is poorly understood specifically for semi-arid and arid regions, their plant species richness and diversity is increasingly threatened by recent and fast evolving agricultural transformation processes. This has been particularly claimed for traditional jubraka HG systems of Sudan. Therefore, sixty-one HGs in four villages of the Nuba Mountains, South-Kordofan Province, Sudan, were randomly selected, geographically recorded and plant richness and abundance determined and plant diversity parameters ca
lculated. In addition, socio-economic household data were assessed by interviews and soil samples taken to allow a comprehensive analysis of putative factors affecting HG plant diversity across different villages, levels of commercialization and plant species composition based clusters. A total of 110 species from 35 plant families were grown in the HGs along with 71 ornamentals. Perennial species accounted for 57 % including 12 indigenous fruit tree (IFT) species and six exotic fruit tree species. Mean species richness of useful plant species (excluding ornamentals) per HG was 23 (range 6â46). On average, 41 % of the 23 species per HG were of exotic origin, however, with a large range (21â83 %) among locations. Mean diversity and evenness indices were 1.46 (range 0.49â2.42) and 0.48 (0.15â0.87), respectively. The level of commercialization of HGs only marginally affected species diversity measures although the species richness was significantly higher for commercial than subsistence HGs. Species richness was higher on lower (6.6â7.2) pH soils. IFT richness was highly variable, but non-significantly different across the four locations. Plant species richness and diversity was high in comparison with other HG systems in semi-arid regions. Cluster analysis was found to be a valuable tool to classify HGs and to extract homogeneous HG types with low, intermediate and high richness and diversity. In addition, the share of exotic and ornamental species in HGs indicated a trend towards the loss of traditional farming practices, particularly in areas with good market access. The data did not indicate the hypothesized loss of inter-specific diversity due to commercialization and species richness was numerically even higher for market-oriented HGs compared to subsistence ones
Replication data for: Competition and facilitation-related factors impacts on crop performance in an agro-forestry parkland system in Burkina Faso
No full textParkia biglobosa and Vitellaria paradoxa are known to improve soil fertility and redistribute water under their crowns in parkland systems. A field experiment was conducted to separate above and below-ground interactions between these species and associated Sorghum bicolor using root trenching and crown pruning during three cropping seasons. Trenching increased soil water availability because Sorghum plants displayed higher leaf water potential (-0.73 ± 0.11 MPa) in the trenched plots than control plots (-1.32 ± 0.14 MPa). There were no significant differences in grain (315 ± 80 kg ha-1 versus 217 ± 48 kg ha-1) and straw biomass (1639 ± 295 kg ha-1 versus 1307 ± 278 kg ha-1) yields between trenched and control plots. Crown pruning increased sorghum grain yield in th
e trenched plots in 2008 and 2009 under P. biglobosa while the opposite happened under V. paradoxa. Better performance of Sorghum in the trenched plots under unpruned V. paradoxa trees than pruned trees could be an indication that light was less limiting under this species as previously thought but also that crown removal induced soil water evaporation and decreased soil water content under this species. An implication of this is that recommendations for including trees in cropland, or for management of existing trees within cropland, must be context and species specific
Replication data for: No appropriate technology so far for Ricinodendron heudelotii (Baill. Pierre ex Pax) processing in Cameroon: Performance of mechanized kernel extraction
No full textRicinodendron heudelotii kernels are an important source of income for rural wome
n in the humid tropics of Africa. Manual kernel extraction is time consuming and efforts have been made to mechanize the process. However, mechanical damage to kernels remains an issue. Within the socioeconomic and resource ecology context in the central region of Cameroon, a prototype machine for extracting njansang kernels was developed and has been tested since 2007, then evaluated using a learning selection model. Surveys with users and non-users suggested a shift towards male and younger users. The advantages of rapid kernel extraction are partly offset by the requirement to sort out broken kernels, leading to a total time requirement of 60.87 min for manual processing and 2.08 + 39.56 min for mechanical extraction + manual sorting. The technology needs further improvement to deliver the expected increase in labour efficiency and economic advantages for rural women. The study was carried out in the small community of Epkwassong, 42 km from Ayos city, Nyong-et-Mfoumou Division in the Central region of Cameroon. Epkwassong was chosen because njansang is common here and women in the village have a good knowledge of its exploitation. The njansang producer group âFaâa Si Obeâ is well-organized and has been selling njansang as a group since 2005. In terms of socio-economic and biophysical characteristics, Epkwassong is in many ways representative of the humid forest zone of Cameroon, and even of the Congo Basin. Epkwassong is located in a forest zone with bimodal rainfall l(1500 to 2000 mm per year in average) characterized bya Guinean climate with 4 seasons (main dry season from December to February; main rainy season from March to June; short dry season from July to August; short rainy season from September to November). The average temperature is 25°C and the main economic activities of the area are agriculture, artisanal fishing in the rivers Nyong-et-Mfoumou and hunting. Commercialization of njansang is the fourth most important source of income after plantain, cocoa and cocoyam. R. heudelotii in this zone is typically found in abandoned farmland and is often retained when land is cleared for farming because it improves soil fertility and provides shade required for cocoa cash cropping