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This study investigates the carbon (C) sequestration of traditional cocoa agroforestry systems in the Eastern Region of Ghana and the theoretical impact of CO2 emission rights trading on their profitability. The study was conducted in four villages of Suhum Municipality, two each with either conventional or organic cocoa cultivation systems. Profitability was calculated using net present value of net cashflow (NPV), benefit cost ratio (BCR), and modified internal rate of return (MIRR). Carbon revenues were calculated using CO2 emission trading rights prices ranging from 7.5 € tCO2eq.−1 (average EU trading price) to 42 € tCO2eq.−1(estimated social cost of CO2 release). We tested the sensitivity of profitability indicators with three scenarios: 300% increase in interest rates, 20% yield reduction, and 10% increase in cost. NPV without CO2 payment for conventional agroforest was 20% higher than that of organic agroforest. Contrarily, BCR for the organic system was 30% larger than for the conventional counterpart. Profitability indicators for both systems were most sensitive to the 300% interest rate. The average C sequestered was 153 ± 13 t ha−1 whereby soil contributed the largest fraction with an average of 88 ± 11 t ha−1. Total C sequestered in the organic system was 30% higher than in the conventional system. In conclusion, CO2 payments can improve the attractiveness of organic cocoa cultivation for farmers, although the paid price must be oriented to the estimated social costs caused by CO2 release rather than the currently used trading price in the EU.

Olea europaea subsp. cuspidata (Wall. & G. Don) Cif. is one of the six subspecies important for domestication of olive described as having valuable breeding traits. It is distributed from South Africa to the Middle East and the Mediterranean region to China mainly at mid to high altitudes with adequate precipitation. The currently rather fragmented Olea europaea subsp. cuspidata populations likely represent outposts of a formerly larger and more connected area and are hence vulnerable to additional stresses such as erratic weather extremes and anthropogenic influences. This may result in further fragmentation of stands, shifts in demography, increased clonal growth, lower genetic diversity, and higher differentiation between olive stands. In this study, we present data on Olea europaea subsp. cuspidata growing in the Hajar Mountains, Sultanate of Oman, a large area subjected to many anthropogenic disturbances. We used dendrological traits and genetic parameters to infer its stand and population genetic structure, levels of genetic diversity, and differentiation. To accomplish this, 366 individual trees in total were inventoried and 188 of them genotyped using 12 microsatellite markers. Dendrological measures indicated disturbances mainly due to human activities. Height and crown area of individuals averaged 3.7 m (ranging from 0.2 to 12 m) and 14 m (ranging from 1 to 18 m), respectively. The stand conditional index was mainly 50%. The identified genetic variation within the sampled areas was relatively moderate. The expected and observed heterozygosity equalled 0.55–0.58 and 0.62–0.64, respectively. All individual genotypes were unique indicating the absence of clones. Though significant genetic differentiation was found, there was no evidence of population substructure suggesting effective pollen and long-distance seed dispersal in the past. However, changes in gene flow patterns may be reflected in the next (sibling) generation. Further studies are necessary to detect any changes in the future and to develop sustainable conservation strategies for this species.

During the past decade, there have been numerous attempts to identify sex-linked molecular genetic markers that can be used to discriminate among male and female trees in date palm (Phoenix dactylifera L.). In our approach to address this biological problem, we applied a comparative genomics approach and used a candidate sex-linked Tormozembryo Defective (TOZ19) gene found to be male-specific in aspen. Using BLAST against the date palm genome assembly, we found a putative Transducin Beta-like Protein 3 (TBL3) gene in date palm that was highly homologous to the TOZ19 gene and sequenced it in three male and four female trees from four economically important date palm cultivars from Egypt. Based on the obtained multiple nucleotide sequence alignments, male- and female-specific date palm haplotypes were identified by screening single nucleotide polymorphisms (SNPs). Subsequently, a respective gene fragment in additional five date palm samples comprising three females and two males were cloned and sequenced to independently confirm the previously identified putative sex-linked SNPs. The three putative sex-linked SNPs can be used now to discriminate male and female date palms at their seedling stage. This will further enhance and pave the way for commercial date palm cultivation through seeds. The identified molecular markers are relatively easy, cheap, fast, and reproducible sex identification tools. Female date palms are either homozygous or heterozygous, while male date palms are hemizygous at the putative sex-linked loci.

Apple (Malus × domestica) is a main fruit crop of cold temperate regions and traded globally. Despite being a comparatively well documented plant cultigen, available germplasm in many remote regions is still unexplored and threatened. Increasing market demands for modern cultivars and farmers’ preference for high yields may lead to the gradual loss of indigenous varieties. Gilgit-Baltistan in northern Pakistan – a mountainous and remote apple growing region – was selected to study local cultigen diversity by assessing varietal richness and diversity, arboriculture activities as well as phenotypic and genotypic characters of available germplasm. In total, 106 individual apple trees were sampled, and 35 tree owners from seven villages of the two valleys Ishkoman and Baltistan were interviewed. Dendrometric parameters, fruit traits (qualitative and quantitative), and varietal diversity in each village were measured. Genetic variation was estimated using eleven SSR markers and synonyms and homonyms were identified based on cluster analysis. Sixty-one multi-locus genotypes (MLG; mean genotype diversity: 58 %) and 18 putative clones (comprising 2 to 9 ramets) were identified. Varietal diversity was highest in Baltistan where even a wild apple relative (Malus baccata) was discovered. Mean genetic diversity was moderate (He = 0.677), while negative inbreeding coefficients indicated excess of heterozygotes in three genetic clusters. A moderate correlation (r = 0.627, p = 0.001) between phenotypic and genetic dendrograms suggested genetically linked fruit traits, which merits further exploration. Considering the high genetic and phenotypic variability, Gilgit-Baltistan appears a promising source of apple germplasm for future breeding programs. The promotion of local varieties may allow farmers to diversify their produce and derived sources of income as well as to maintain a historically important bio-cultural heritage of Gilgit-Baltistan. To this end, comprehensive conservation strategies combined with further participatory research will be needed.

Riparian forests belong to the most vulnerable ecosystems worldwide and have been severely affected by logging, livestock grazing and altered flooding over the last decades. Several riparian tree species including Populus spp. face a risk of loss in genetic diversity and associated adaptive potential. A model species for such systems in Central Asia is Populus laurifolia , which in Western Mongolia is commonly confined to river floodplains of the Altai Mountains. Populations appear heavily fragmented and show evidence for lack of regeneration. In order to better understand the ecology of these systems and to provide conservation in the study region and beyond, a total of 615 individuals from first and second order water courses of the Bulgan River in Hovd Aimag were mapped, followed by measurements of diameter at breast height, tree height and sampling of leaf material. Five nuclear microsatellites were employed to estimate standard genetic diversity measures and genetic structure within and among populations. Size class distribution showed a clear sign of over-aging, suggesting that establishment of young individuals is hampered by intense grazing/browsing. Genetic diversity tended to increase downstream, though evidence for genetic differentiation and genetic structuring was ambiguous. This pointed to a time lag between demographic and genetic responses to land use, explained by longevity of trees coupled with clonal growth. As hampered regeneration of plant stands may affect future ecosystem stability, controlled grazing strategies should be considered to secure long-term persistence of stands.

SUMMARYThe use of date palm (Phoenix dactyliferaL.) has been closely connected with the survival of people in arid areas given their fruits´ high concentration of energy, fibre, minerals, vitamins and 16 amino acids. The arid climate and sandy or clayey loam soils in many parts of Pakistan are ideal for the cultivation of date palm, which contributes to feeding the country's rapidly growing population. To fill knowledge gaps on the effects of cultivar diversity and cultivation sites on the nutritional properties of dates, the present project studied dates and related physical and chemical soil properties across six districts in four provinces of Pakistan: Jhang, Muzaffargarh and Bahawalpur in Punjab; Dera Ismail Khan (D. I. Khan) in Khyber Pakhtunkhwa (KPK); Khairpur in Sindh and Panjgur in Baluchistan. To this end, during 2012–2013, a total of 170 households (HHs) were selected using a snowball sampling approach. Thirty-nine different date palm cultivars with diverse nutritional properties are grown in the study area. In these total soluble solids (TSS) were highest in Muzawati and Koharba cultivars, while cultivars and site conditions significantly affected TSS, minerals (calcium and magnesium), acidity, and firmness of dates. Concentration of CaCO3and bulk density (BD) of soils varied widely, while hydraulic conductivity (HC) was similar across sites (p= 0.128). Mean soil pH was highest in Panjgur (8.3) and lowest in Muzaffargarh (7.6), soil organic matter content was highest in Jhang (0.8%) and lowest in D. I. Khan (0.6%) and plant available phosphorous (P) was highest in Muzaffargarh (7.8 mg kg−1) and lowest in Panjgur (6.0 mg kg−1). As indicated by correlation analysis BD and cation exchange capacity of soils seemed to affect TSS, whereas concentration of CaCO3and available P were correlated with calcium concentration of dates. HC and electrical conductivity, however, seemed to have little effect on dates´ nutritional properties.

Different conservation measures including domestication approaches are needed to preserve rare and extensively used plant species and to satisfy future market demands. Snow lotus (a common name used for a number of high altitude species in central Asia) species in Mongolia are important medicinal plants, mostly endangered at the regional level due to the extensive use for medicinal purposes and naturally limited distribution ranges. In order to develop effective conservation and cultivation approaches we studied the morphological and genetic diversity as well as the seed germination behavior of three populations of Saussurea involucrata in the Altay Mountains of Western Mongolia. Plant height and leaf length were measured on 41–53 randomly selected individuals in each population. Enhancement of seed germination was studied using either mechanical or chemical scarification with potassium nitrate and gibberellic acid. Genetic diversity within and among three populations of the species was analyzed using Amplified Fragment Length Polymorphisms. Plants in three populations differed in height and leaf length (P

Wild edible fruits hold great potential for improving human diets, especially in agricultural societies of the developing world. In Africa, a well-known supplier of such fruits is the baobab (Adansonia digitata L., Malvaceae), one of the most remarkable trees of the world. Several studies in different African countries have highlighted this indigenous fruit tree as a priority species for domestication and expanded use. However, internationally available information on baobab in East Africa, particularly in Sudan and Kenya, remains scarce. This review aims to shed light on the ecology, diversity and current level of utilization of baobab in East Africa in order to facilitate domestication and conservation of the species. A list of priority research areas is provided at the end of the review to encourage further studies and investment in this unique plant taxon.

Wild yam species ( Dioscorea spp.) provide important supplementary food and thus contribute directly to the livelihood and well-being of local people in SW Madagascar. Given the ongoing exploitation of this resource, there is a necessity to identify and predict yam species distribution along environmental gradients to improve our understanding of sustainable management of this resource. Therefore, the aims of the current study were to identify predictors for the distribution of important wild yam species and to spatially predict their availability. To this end species abundance and environmental variables were collected in the field using a systematic sampling approach within a yams collection area of four villages (58 plots). A redundancy analysis (RDA) was conducted to investigate the relationship between wild yam species and 12 environmental variables. Species distribution models and species response curves were established for the most abundant wild yam species using nonparametric multiplicative regression (NPMR). These models were subsequently used in conjunction with geospatial data for predictive mapping. RDA depicted a clear pattern of species habitats with D. alatipes occurring in dry spiny forests on calcareous soils at remote places, while D. bemandry and D. fandra were found in forest habitats on sandy soils with high harvest intensities. The NPMR models explained 88% ( D. alatipes ), 82% ( D . bemandry ) and 37% ( D. fandra ) of the variation in species abundance. Sensitivity analysis indicated the importance of vegetation structure, human interventions, and soil characteristics in determining wild yam distribution. Predicted distribution maps showed that the population of wild yam is scarce and mostly located in restricted areas of open spiny forests and dry spiny forest thickets, where harvest intensity is high. This study highlights the need for long-term assessment and public awareness actions on yam harvest practices as well as the importance of anthropogenic factors for the distribution of yam as a key forest resource in SW Madagascar.

Widely variable inter- and intra-seasonal rainfall increases risks of agricultural production in the Nuba Mountains of Sudan, which are one of the country's most vulnerable areas with respect to climate change. This study aims to identify trends in rainfall amount at different temporal resolutions as well as changes and probabilities of rainfall-induced agricultural events. Long-term daily rainfall records (60 years) from two weather stations, Kadugli and Rashad, were computed to daily, monthly and annual values and rainfall-induced events were computed using the INSTAT + software. Subsequently, these calculated values and events were checked for possible monotonic trends from 1950 to 2009 and 1970 to 2009 by Mann–Kendall tests. Over the period from 1970 to 2009, annual rainfall showed no statistically significant change for either station. However, during this period an increase of low rainfall events (>0.85 mm to ≤3 mm) by 15 days coinciding with a decline in the number of medium daily rainfall classes (>10 mm to ≤20 mm) by 4 days was observed in Rashad. This increase is of concern since low rainfall events do not contribute to the crop water balance and therefore may thus be largely irrelevant for rainfed farmers' crop production. Furthermore, daily rainfall data enabled frequency calculations of a successful or failed start of the growing season, of high intensity rainfall events (90th, 95th and 99th percentiles) and of different dry spell length classes (>7, >14 and >21 days; 1 to ≤7 days, 8 to ≤14, 15 to ≤21 and >21). Additionally, probability calculations of the minimum lengths of growing season and the occurring of dry spell lengths based on specific dates were conducted. Since for these rainfall-induced agricultural events either no statistically significant changes or trends resulting only in minor changes of probabilities were observed, our risk statements seem to be reliable for the next years. The results of this study may contribute to a better assessment of crop management risks under rainfed farming in the Nuba Mountains.

Ecologically sound natural resources management is still the backbone of rural livelihoods in many regions of the world. The Altai-Dzungarian region between China and Mongolia constitutes an ideal site to study how political, economic, infrastructural, and cultural differences affect rural livelihoods. Structured semi-quantitative interviews were conducted with 483 households on both sides to characterise their current livelihood strategies and assess the importance of the various activities for the households’ current socio-economic situation by means of the categorical principal component and two-step cluster analysis. In total, four livelihood clusters were identified across both regions, whereby one cluster was only present in Mongolia. In general, all clusters mirrored the transition from almost pure pastoralist to agro-pastoralist livelihood strategies. While animal husbandry was more common in Mongolia and crop farming more common in China, most households in both countries pursued a rather mixed approach. The composition of the herds, as well as the richness and diversity of the livestock species, differed significantly between the countries and was generally higher in Mongolia. Supplementary feedstuff and pesticide and fertiliser use were higher in China, along with diversification of produces. Our analysis indicates that until very recently the livelihood strategies on both sides of the border were the same, manifesting in the fact that we can define three identical clusters across countries (environment factor) even though there are slight differences in land, livestock and asset endowment.

Intensification of homegardens in the Nuba Mountains may lead to increases in C and nutrient losses from these small-scale land-use systems and potentially threaten their sustainability. This study, therefore, aimed at determining gaseous C and N fluxes from homegarden soils of different soil moisture, temperature, and C and N status. Emissions of CO2, NH3, and N2O from soils of two traditional and two intensified homegardens and an uncultivated control were recorded bi-weekly during the rainy season in 2010. Flux rates were determined with a portable dynamic closed chamber system consisting of a photo-acoustic multi-gas field monitor connected to a PTFE coated chamber. Topsoil moisture and temperature were recorded simultaneously to the gas measurements. Across all homegardens emissions averaged 4,527 kg CO2-C ha−1, 22 kg NH3-N ha−1, and 11 kg N2O-N ha−1 for the observation period from June to December. Flux rates were largely positively correlated with soil moisture and predominantly negatively with soil temperature. Significant positive, but weak (rs

UNLABELLED • PREMISE OF THE STUDY Adansonia digitata L. is one of the most important indigenous fruit trees of mainland Africa. Despite its significance for subsistence and income generation of local communities, little is known about the genetic and morphological variability of East African populations of A. digitata, including those of Sudan. The aim of the current study, therefore, was to analyze genetic and morphological variability of different baobab populations in Kordofan, Sudan and to estimate the effect of human intervention on genetic differentiation and diversity.• METHODS A total of 306 trees were randomly sampled from seven spatially separated locations in the Nuba Mountains, Sudan, to cover a wide range of differing environmental gradients and management regimes ('homesteads' and 'wild'). Genetic analyses were conducted using nine microsatellite markers. Because of the tetraploid nature of A. digitata, different approaches were applied to estimate patterns of genetic diversity. Investigations were completed by measurements of dendrometric and fruit morphological characters.• KEY RESULTS Genetic diversity was balanced and did not differ between locations or management regimes, although tendencies of higher diversity in 'homesteads' were observed. A Bayesian cluster approach detected two distinct gene pools in the sample set, mainly caused by one highly diverse population close to a main road. The variability of tree characters and fruit morphometries was high, and significantly different between locations.• CONCLUSIONS Results indicated a rather positive effect with human intervention. The observed populations provide a promising gene pool and likely comprise ecotypes well-adapted to environmental conditions at the northern distribution range of the species, which should be considered in conservation and management programs.

Management intensification has raised concerns about the sustainability of homegardens in the Nuba Mountains, Sudan. This study aimed at assessing the sustainability of these agroecosystems following the approach of carbon (C) and nutrient balances. Three traditional (low input) and three intensified (high input) homegardens were selected for monitoring of relevant input and output fluxes of C, nitrogen (N), phosphorus (P) and potassium (K). The fluxes comprised those related to management activities (soil amendments, irrigation, and biomass removal) as well as estimates of biological N2 fixation, C fixation by photosynthesis, wet and dry deposition, gaseous emission, and leaching. Annual balances for C and nutrients amounted to −21 kg C ha−1, −70 kg N ha−1, 9 kg P ha−1 and −117 kg K ha−1 in high input homegardens and to −1,722 kg C ha−1, −167 kg N ha−1, −9 kg P ha−1 and −74 kg K ha−1 in low input homegardens. Photosynthesis C was the main C input flux with averaged of 7,047 and 5,610 kg C ha−1 a−1 in high and low input systems, respectively. Biological N2 fixation (17 kg N ha−1 a−1) was relevant only in low input systems. In both systems, the annual input of 77 kg K ha−1 through dust was highly significant and annual gaseous C losses of about 5,900 kg C ha−1 were the main C loss. In both garden types, the removal of biomass accounted for more than half of total nutrient exports of which one-third resulted from weeding and removal of plant residues and two-third from harvest. The observed negative nutrient balances may lead to a long-term decline of crop yields. Among other measures the reuse of C and nutrients in biomass removals during the cleaning of homegardens may allow to partially close C and nutrient cycles.

Traditional 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 calculated. 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 6–46). On average, 41 % of the 23 species per HG were of exotic origin, however, with a large range (21–83 %) among locations. Mean diversity and evenness indices were 1.46 (range 0.49–2.42) and 0.48 (0.15–0.87), 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 (6.6–7.2) 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.

Iterative domestication processes by humans such as selection, translocation and cultivation are known to affect the morphological and genetic diversity of tree species. Since many of these species occur also in human-created homegardens (HG) this type of agroecosystem therefore represents an ideal setting to study such domestication processes. The threatened indigenous fruit tree Ziziphus spina-christi occurs in HGs and forests of the Nuba Mountains, Sudan, and was therefore selected as a model species. Five locations were sampled and the geographical position of 250 trees determined. Each location was subdivided into HG and forest sites. The diversities of morphological traits and amplified fragment length polymorphisms were assessed to study variation within and among locations and sites. Diversity of dendrometric parameters and fruit morphometries was high and differed significantly among locations. Environmental parameters affected dendrometry and fruit size, but applied regression models were of low explanatory power. Although statistically not significant, mean fruit measures were continuously larger in HGs than in forests. Higher genetic diversity was observed in HG samples. Larger dendrometric and fruit morphometric traits are likely to result from better growing conditions in HGs and/or human selection of germplasm. This is in line with the higher genetic diversity in HGs which may be a consequence of the admixture of germplasm from different origins planted in HGs. Z. spina-christi underwent incipient steps of domestication. High genetic diversity in HGs suggests those as valuable spots of improved germplasm and for on-farm conservation purposes.

To understand the spatial structure of monospecific Tugai forests (Xinjiang Province, China) growing as gallery woods nourished by ground water, root suckering in Populus euphratica was studied by a combination of morphological and molecular analyses. Seedlings grow a deep tap root and keep this as adult trees, whereas root suckers never develop a tap root but utilize the horizontally stretching root of their parent trees. The resulting reverse “T” root architecture distinguishes reliably even adult root suckers from generatively grown trees. Due to assimilate input from the root sucker, the distal root (pointing away from the parent tree) becomes thicker soon than its proximal root, which allows determination of the direction of vegetative growth. One stand including 279 young trees germinated from seeds and 267 root suckers was mapped completely, and selected suckers were assigned to parent trees by genotyping with microsatellite DNA. Root suckers develop up to 40 m away from parent trees on horizontal “spacer” roots, usually originating not deeper than 20 cm below surface. Trees begin with root suckering between 10 and 15 years, shortly before reaching flowering age. Cutting experiments indicated reduced survival of young root suckers disconnected from the parent tree. Without a tap root and with a rooting point close to the surface, declining ground water levels should lower the fitness of root suckers even more than that of generatively grown trees.