Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    The Global Politics of Water Grabbing
    Franco, J. ; Mehta, L. ; Veldwisch, G.J.A. - \ 2013
    Third World Quarterly 34 (2013)9. - ISSN 0143-6597 - p. 1651 - 1675.
    south-africa - human-rights - land deals - management - representation - mozambique - governance
    The contestation and appropriation of water is not new, but it has been highlighted by recent global debates on land grabbing. Water grabbing takes place in a field that is locally and globally plural-legal. Formal law has been fostering both land and water grabs but formal water and land management have been separated from each otheran institutional void that makes encroachment even easier. Ambiguous processes of global water and land governance have increased local-level uncertainties and complexities that powerful players can navigate, making them into mechanisms of exclusion of poor and marginalised people. As in formal land management corporate influence has grown. For less powerful players resolving ambiguities in conflicting regulatory frameworks may require tipping the balance towards the most congenial. Yet, compared with land governance, global water governance is less contested from an equity and water justice perspective, even though land is fixed, while water is fluid and part of the hydrological cycle; therefore water grabbing potentially affects greater numbers of diverse water users. Water grabbing can be a powerful entry point for the contestation needed to build counterweights to the neoliberal, corporate business-led convergence in global resource governance discourses and processes. Elaborating a human right to water in response to water grabbing is urgently needed.
    Combining analytiacal frameworks to assess livelihood vulnerability to climate change and analyse adaptiation option
    Reed, M.S. ; Podesta, G. ; Fazey, I. ; Geeson, N. ; Hessel, R. ; Hubacek, K. ; Letson, D. ; Nainggolan, D. ; Prell, C. ; Rickenbach, M.G. ; Ritsema, C.J. ; Schwilch, G. ; Springer, L.C. ; Thomas, A.D. - \ 2013
    Ecological Economics 94 (2013). - ISSN 0921-8009 - p. 66 - 77.
    natural-resource management - adaptive capacity - local-communities - rational choice - south-africa - sustainability - agriculture - variability - indicators - challenges
    Experts working on behalf of international development organisations need better tools to assist land managers in developing countries maintain their livelihoods, as climate change puts pressure on the ecosystem services that they depend upon. However, current understanding of livelihood vulnerability to climate change is based on a fractured and disparate set of theories and methods. This review therefore combines theoretical insights from sustainable livelihoods analysis with other analytical frameworks (including the ecosystem services framework, diffusion theory, social learning, adaptive management and transitions management) to assess the vulnerability of rural livelihoods to climate change. This integrated analytical framework helps diagnose vulnerability to climate change, whilst identifying and comparing adaptation options that could reduce vulnerability, following four broad steps: i) determine likely level of exposure to climate change, and how climate change might interact with existing stresses and other future drivers of change; ii) determine the sensitivity of stocks of capital assets and flows of ecosystem services to climate change; iii) identify factors influencing decisions to develop and/or adopt different adaptation strategies, based on innovation or the use/substitution of existing assets; and iv) identify and evaluate potential trade-offs between adaptation options. The paper concludes by identifying interdisciplinary research needs for assessing the vulnerability of livelihoods to climate change.
    The use of woodland products to cope with climate variability in communal areas in Zimbabwe
    Woittiez, L.S. ; Rufino, M.C. ; Giller, K.E. ; Mapfumo, P. - \ 2013
    Ecology and Society 18 (2013)4. - ISSN 1708-3087
    rural livelihoods - south-africa - ecosystem services - savanna resources - fruit-trees - valuation - biodiversity - availability - consumption - households
    Common lands provide smallholder farmers in Africa with firewood, timber, and feed for livestock, and they are used to complement human diets through the collection of edible nontimber forest products (NTFPs). Farmers have developed coping mechanisms, which they deploy at times of climatic shocks. We aimed to analyze the importance of NTFPs in times of drought and to identify options that could increase the capacity to adapt to climate change. We used participatory techniques, livelihood analysis, observations, and measurements to quantify the use of NTFPs. Communities recognized NTFPs as a mechanism to cope with crop failure. We estimated that indigenous fruits contributed to approximately 20% of the energy intake of wealthier farmers and to approximately 40% of the energy intake of poor farmers in years of inadequate rainfall. Farmers needed to invest a considerable share of their time to collect wild fruits from deforested areas. They recognized that the effectiveness of NTFPs as an adaptation option had become threatened by severe deforestation and by illegal harvesting of fruits by urban traders. Farmers indicated the need to plan future land use to (1) intensify crop production, (2) cultivate trees for firewood, (3) keep orchards of indigenous fruit trees, and (4) improve the quality of grazing lands. Farmers were willing to cultivate trees and to organize communal conservation of indigenous fruits trees. Through participatory exercises, farmers elaborated maps, which were used during land use discussions. The process led to prioritization of pressing land use problems and identification of the support needed: fast-growing trees for firewood, inputs for crop production, knowledge on the cultivation of indigenous fruit trees, and clear regulations and compliance with rules for extraction of NTFPs. Important issues that remain to be addressed are best practices for regeneration and conservation, access rules and implementation, and the understanding and management of competing claims on the common lands. Well-managed communal resources can provide a strong tool to maintain and increase the rural communities’ ability to cope with an increasingly variable climate.
    A phylogenetic re-evaluation of Phyllosticta (Botryosphaeriales)
    Wikee, S. ; Lombard, L. ; Nakashima, C. ; Motohashi, K. ; Chukeatirote, E. ; Cheewangkoon, R. ; McKenzie, E.H.C. ; Hyde, K.D. ; Crous, P.W. - \ 2013
    Studies in Mycology 76 (2013)1. - ISSN 0166-0616 - p. 1 - 29.
    citrus black spot - ribosomal dna - south-africa - fungus - banana - identification - eucalyptus - anamorph - vaccinii - nuclear
    Phyllosticta is a geographically widespread genus of plant pathogenic fungi with a diverse host range. This study redefines Phyllosticta, and shows that it clusters sister to the Botryosphaeriaceae (Botryosphaeriales, Dothideomycetes), for which the older family name Phyllostictaceae is resurrected. In moving to a unit nomenclature for fungi, the generic name Phyllosticta was chosen over Guignardia in previous studies, an approach that we support here. We use a multigene DNA dataset of the ITS, LSU, ACT, TEF and GPDH gene regions to investigate 129 isolates of Phyllosticta, representing about 170 species names, many of which are shown to be synonyms of the ubiquitous endophyte P. capitalensis. Based on the data generated here, 12 new species are introduced, while epitype and neotype specimens are designated for a further seven species. One species of interest is P. citrimaxima associated with tan spot of Citrus maxima fruit in Thailand, which adds a fifth species to the citrus black spot complex. Previous morphological studies lumped many taxa under single names that represent complexes. In spite of this Phyllosticta is a species-rich genus, and many of these taxa need to be recollected in order to resolve their phylogeny and taxonomy.
    Phylogenetic lineages in the Botryosphaeriales: A systematic and evolutionary framework
    Slippers, B. ; Boissin, E. ; Phillips, A.J.L. ; Groenewald, J.Z. ; Wingfield, M.J. ; Postma, A. ; Burgess, T. ; Crous, P.W. - \ 2013
    Studies in Mycology 76 (2013)1. - ISSN 0166-0616 - p. 31 - 49.
    multiple gene genealogies - ribis species complex - combining data - south-africa - fungi - incongruence - proteaceae - origin - angiosperms - characters
    The order Botryosphaeriales represents several ecologically diverse fungal families that are commonly isolated as endophytes or pathogens from various woody hosts. The taxonomy of members of this order has been strongly influenced by sequence-based phylogenetics, and the abandonment of dual nomenclature. In this study, the phylogenetic relationships of the genera known from culture are evaluated based on DNA sequence data for six loci (SSU, LSU, ITS, EF1, BT, mtSSU). The results make it possible to recognise a total of six families. Other than the Botryosphaeriaceae (17 genera), Phyllostictaceae (Phyllosticta) and Planistromellaceae (Kellermania), newly introduced families include Aplosporellaceae (Aplosporella and Bagnisiella), Melanopsaceae (Melanops), and Saccharataceae (Saccharata). Furthermore, the evolution of morphological characters in the Botryosphaeriaceae were investigated via analysis of phylogeny-trait association. None of the traits presented a significant phylogenetic signal, suggesting that conidial and ascospore pigmentation, septation and appendages evolved more than once in the family. Molecular clock dating on radiations within the Botryosphaeriales based on estimated mutation rates of the rDNA SSU locus, suggests that the order originated in the Cretaceous period around 103 (45-188) mya, with most of the diversification in the Tertiary period. This coincides with important periods of radiation and spread of the main group of plants that these fungi infect, namely woody Angiosperms. The resulting host-associations and distribution could have influenced the diversification of these fungi.
    Characterisation of Neofusicoccum species causing mango dieback in Italy
    Ismail, A.M. ; Cirvilleri, G. ; Lombard, L. ; Crous, P.W. ; Groenewald, J.Z. ; Polizzi, G. - \ 2013
    Journal of Plant Pathology: rivista di patologia vegetale 95 (2013)3. - ISSN 1125-4653 - p. 549 - 557.
    mangifera-indica - phylogenetic analysis - south-africa - 1st report - sp-nov - botryosphaeria - pathogenicity - lasiodiplodia - morphology - grapevine
    Species of Botryosphaeriaceae are important fungal pathogens of mango worldwide. A survey of 11 mango orchards located in the provinces of Catania, Messina, Palermo and Ragusa (Sicily, southern Italy), resulted in the isolation of a large number (76) of Neofusicoccum isolates associated with decline and dieback symptoms. Isolates were identified based on morphology and DNA sequence data analyses of the internal transcribed spacer region of the nrDNA and partial translation of the elongation factor 1-alpha gene regions. Two species of Neofusicoccum were identified, which included N. parvum and N. australe, the former of which was the dominant species. The high incidence in local orchards and the pathogenicity results indicate that N. parvum and N. australe are important pathogens of mango in Sicily where they may significantly limit mango production.
    Fungal Planet description sheets: 154–213
    Crous, P.W. ; Wingfield, M.J. ; Guarro, J. ; Cheewangkoon, R. ; Bank, M. van der; Swart, W.J. ; Stchigel, A.M. ; Cano-Lira, J.F. ; Roux, J. ; Madrid, H. ; Damm, U. ; Wood, A.R. ; Shuttleworth, L.A. ; Hodges, C.S. ; Munster, M. ; Jesús Yáñez-Morales, M. de; Zúñiga-Estrada, L. ; Cruywagen, E.M. ; Hoog, G.S. de; Silvera, C. ; Najafzadeh, J. ; Davison, E.M. ; Davison, P.J.N. ; Barrett, M.D. ; Barrett, R.L. ; Manamgoda, D.S. ; Minnis, A.M. ; Kleczewski, N.M. ; Flory, S.L. ; Castlebury, L.A. ; Clay, K. ; Hyde, K.D. ; Maússe-Sitoe, S.N.D. ; Chen, S. ; Lechat, C. ; Hairaud, M. ; Lesage-Meessen, L. ; Pawlowska, J. ; Wilk, M. ; Sliwinska-Wyrzychowska, A. ; Metrak, M. ; Wrzosek, M. ; Pavlic-Zupanc, D. ; Maleme, H.M. ; Slippers, B. ; Mac Cormack, W.P. ; Archuby, D.I. ; Grünwald, N.J. ; Tellería, M.T. ; Dueñas, M. ; Martín, M.P. ; Marincowitz, S. ; Beer, Z.W. de; Perez, C.A. ; Gené, J. ; Marin-Felix, Y. ; Groenewald, J.Z. - \ 2013
    Persoonia 31 (2013). - ISSN 0031-5850 - p. 188 - 296.
    sp-nov - colletotrichum-sansevieriae - anamorph genus - south-africa - 1st report - phytophthora-ipomoeae - leaf-blight - genera - phylogeny - botryosphaeriaceae
    Novel species of microfungi described in the present study include the following from South Africa: Camarosporium aloes, Phaeococcomyces aloes and Phoma aloes from Aloe, C. psoraleae, Diaporthe psoraleae and D. psoraleae-pinnatae from Psoralea, Colletotrichum euphorbiae from Euphorbia, Coniothyrium prosopidis and Peyronellaea prosopidis from Prosopis, Diaporthe cassines from Cassine, D. diospyricola from Diospyros, Diaporthe maytenicola from Maytenus, Harknessia proteae from Protea, Neofusicoccum ursorum and N. cryptoaustrale from Eucalyptus, Ochrocladosporium adansoniae from Adansonia, Pilidium pseudoconcavum from Greyia radlkoferi, Stagonospora pseudopaludosa from Phragmites and Toxicocladosporium ficiniae from Ficinia. Several species were also described from Thailand, namely: Chaetopsina pini and C. pinicola from Pinus spp., Myrmecridium thailandicum from reed litter, Passalora pseudotithoniae from Tithonia, Pallidocercospora ventilago from Ventilago, Pyricularia bothriochloae from Bothriochloa and Sphaerulina rhododendricola from Rhododendron. Novelties from Spain include Cladophialophora multiseptata, Knufia tsunedae and Pleuroascus rectipilus from soil and Cyphellophora catalaunica from river sediments. Species from the USA include Bipolaris drechsleri from Microstegium, Calonectria blephiliae from Blephilia, Kellermania macrospora (epitype) and K. pseudoyuccigena from Yucca. Three new species are described from Mexico, namely Neophaeosphaeria agaves and K. agaves from Agave and Phytophthora ipomoeae from Ipomoea. Other African species include Calonectria mossambicensis from Eucalyptus (Mozambique), Harzia cameroonensis from an unknown creeper (Cameroon), Mastigosporella anisophylleae from Anisophyllea (Zambia) and Teratosphaeria terminaliae from Terminalia (Zimbabwe). Species from Europe include Auxarthron longisporum from forest soil (Portugal), Discosia pseudoartocreas from Tilia (Austria), Paraconiothyrium polonense and P. lycopodinum from Lycopodium (Poland) and Stachybotrys oleronensis from Iris (France). Two species of Chrysosporium are described from Antarctica, namely C. magnasporum and C. oceanitesii. Finally, Licea xanthospora is described from Australia, Hypochnicium huinayensis from Chile and Custingophora blanchettei from Uruguay. Novel genera of Ascomycetes include Neomycosphaerella from Pseudopentameris macrantha (South Africa), and Paramycosphaerella from Brachystegia sp. (Zimbabwe). Novel hyphomycete genera include Pseudocatenomycopsis from Rothmannia (Zambia), Neopseudocercospora from Terminalia (Zambia) and Neodeightoniella from Phragmites (South Africa), while Dimorphiopsis from Brachystegia (Zambia) represents a novel coelomycetous genus. Furthermore, Alanphillipsia is introduced as a new genus in the Botryosphaeriaceae with four species, A. aloes, A. aloeigena and A. aloetica from Aloe spp. and A. euphorbiae from Euphorbia sp. (South Africa). A new combination is also proposed for Brachysporium torulosum (Deightoniella black tip of banana) as Corynespora torulosa. Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.
    Adapting to Climate Variability and Change: Experiences from Cereal-Based Farming in the Central Rift and Kobo Valleys, Ethiopia
    Kassie, B.T. ; Hengsdijk, H. ; Rötter, R. ; Kahiluoto, H. ; Asseng, S. ; Ittersum, M.K. van - \ 2013
    Environmental Management 52 (2013)5. - ISSN 0364-152X - p. 1115 - 1131.
    sub-saharan africa - farmer perceptions - northern ethiopia - coping strategies - south-africa - rainfall - adaptation - agriculture - drought - risk
    Small-holder farmers in Ethiopia are facing several climate related hazards, in particular highly variable rainfall with severe droughts which can have devastating effects on their livelihoods. Projected changes in climate are expected to aggravate the existing challenges. This study examines farmer perceptions on current climate variability and long-term changes, current adaptive strategies, and potential barriers for successful further adaptation in two case study regions—the Central Rift Valley (CRV) and Kobo Valley. The study was based on a household questionnaire, interviews with key stakeholders, and focus group discussions. The result revealed that about 99 % of the respondents at the CRV and 96 % at the Kobo Valley perceived an increase in temperature and 94 % at CRV and 91 % at the Kobo Valley perceived a decrease in rainfall over the last 20–30 years. Inter-annual and intraseasonal rainfall variability also has increased according to the farmers. The observed climate data (1977–2009) also showed an increasing trend in temperature and high inter-annual and intra-seasonal rainfall variability. In contrast to farmers’ perceptions of a decrease in rainfall totals, observed rainfall data showed no statistically significant decline. The interaction among various bio-physical and socio-economic factors, changes in rainfall intensity and reduced water available to crops due to increased hot spells, may have influenced the perception of farmers with respect to rainfall trends. In recent decades, farmers in both the CRV and Kobo have changed farming practices to adapt to perceived climate change and variability, for example, through crop and variety choice, adjustment of cropping calendar, and in situ moisture conservation. These relatively low-cost changes in farm practices were within the limited adaptation capacity of farmers, which may be insufficient to deal with the impacts of future climate change. Anticipated climate change is expected to impose new risks outside the range of current experiences. To enable farmers to adapt to these impacts critical technological, institutional, and market-access constraints need to be removed. Inconsistencies between farmers’ perceptions and observed climate trends (e.g., decrease in annual rainfall) could lead to sub-optimal or counterproductive adaptations, and therefore must be removed by better communication and capacity building, for example through Climate Field Schools. Enabling strategies, which are among others targeted at agricultural inputs, credit supply, market access, and strengthening of local knowledge and information services need to become integral part of government policies to assist farmers to adapt to the impacts of current and future climate change.
    Qualitative evaluation of the Teenage Mothers Project in Uganda: a community-based empowerment intervention for unmarried teenage mothers
    Leerlooijer, J.N. ; Bos, A.E.R. ; Ruiter, R.A.C. ; Reeuwijk, M.A.J. van; Rijsdijk, E. ; Nshakira, N. ; Kok, G. - \ 2013
    BMC Public Health 13 (2013). - ISSN 1471-2458 - 15 p.
    intimate-partner violence - sub-saharan africa - hiv prevention - south-africa - health - adolescents - stigma - risk - trends - school
    Background A large proportion of unmarried teenage mothers in Uganda face physical, psychological, and social problems after pregnancy and childbirth, such as obstetric complications, lack of education, and stigmatisation in their communities. The Teenage Mothers Project (TMP) in Eastern Uganda empowers unmarried teenage mothers to cope with the consequences of early pregnancy and motherhood. Since 2000, 1036 unmarried teenage mothers, their parents, and community leaders participated in economic and social empowerment interventions. The present study explored the changes resulting from the TMP as well as factors that either enabled or inhibited these changes. Methods Semi-structured interviews (N¿=¿23) were conducted with former teenage mothers , community leaders, and project implementers, and lifeline histories were obtained from former teenage mothers (N¿=¿9). Quantitative monitoring data regarding demographic and social characteristics of teenage mother participants (N¿=¿1036) were analysed. Results The findings suggest that, overall, the TMP seems to have contributed to the well-being of unmarried teenage mothers and to a supportive social environment. It appears that the project contributed to supportive community norms towards teenage mothers’ position and future opportunities, increased agency, improved coping with early motherhood and stigma, continued education, and increased income generation by teenage mothers. The study findings also suggest limited change in disapproving community norms regarding out-of-wedlock sex and pregnancy, late active enrolment of teenage mothers in the project (i.e., ten months after delivery of the child), and differences in the extent to which parents provided support. Conclusions It is concluded that strengths of the community-based TMP seem to be its socio-ecological approach, the participatory planning with community leaders and other stakeholders, counselling of parents and unmarried teenage mothers, and the emphasis on education and income generation. The project can improve by earlier active participation of unmarried pregnant adolescents and increased support for parents.
    Benefits of investing in ecosystem restoration
    Groot, R.S. de; Blignaut, J. ; Ploeg, S. van der; Aronson, J. ; Elmqvist, T. ; Farley, J. - \ 2013
    Conservation Biology 27 (2013)6. - ISSN 0888-8892 - p. 1286 - 1293.
    ecological restoration - south-africa - biodiversity - payments - services - opportunities - conservation - metaanalysis - indonesia - working
    Measures aimed at conservation or restoration of ecosystems are often seen as net-cost projects by governments and businesses because they are based on incomplete and often faulty cost-benefit analyses. After screening over 200 studies, we examined the costs (94 studies) and benefits (225 studies) of ecosystem restoration projects that had sufficient reliable data in 9 different biomes ranging from coral reefs to tropical forests. Costs included capital investment and maintenance of the restoration project, and benefits were based on the monetary value of the total bundle of ecosystem services provided by the restored ecosystem. Assuming restoration is always imperfect and benefits attain only 75% of the maximum value of the reference systems over 20 years, we calculated the net present value at the social discount rates of 2% and 8%. We also conducted 2 threshold cum sensitivity analyses. Benefit-cost ratios ranged from about 0.05:1 (coral reefs and coastal systems, worst-case scenario) to as much as 35:1 (grasslands, best-case scenario). Our results provide only partial estimates of benefits at one point in time and reflect the lower limit of the welfare benefits of ecosystem restoration because both scarcity of and demand for ecosystem services is increasing and new benefits of natural ecosystems and biological diversity are being discovered. Nonetheless, when accounting for even the incomplete range of known benefits through the use of static estimates that fail to capture rising values, the majority of the restoration projects we analyzed provided net benefits and should be considered not only as profitable but also as high-yielding investments.
    Sizing up Septoria
    Quaedvlieg, W. ; Verkley, G.J.M. ; Shin, H.D. ; Barreto, R.W. ; Alfenas, A.C. ; Swart, W.J. ; Groenewald, J.Z. ; Crous, P.W. - \ 2013
    Studies in Mycology 75 (2013). - ISSN 0166-0616 - p. 307 - 390.
    molecular-data sets - systematic reappraisal - phylogenetic lineages - genus septoria - ribosomal dna - similar fungi - sooty blotch - south-africa - mycosphaerella - genera
    Septoria represents a genus of plant pathogenic fungi with a wide geographic distribution, commonly associated with leaf spots and stem cankers of a broad range of plant hosts. A major aim of this study was to resolve the phylogenetic generic limits of Septoria, Stagonospora, and other related genera such as Sphaerulina, Phaeosphaeria and Phaeoseptoria using sequences of the the partial 28S nuclear ribosomal RNA and RPB2 genes of a large set of isolates. Based on these results Septoria is shown to be a distinct genus in the Mycosphaerellaceae, which has mycosphaerella-like sexual morphs. Several septoria-like species are now accommodated in Sphaerulina, a genus previously linked to this complex. Phaeosphaeria (based on P. oryzae) is shown to be congeneric with Phaeoseptoria (based on P. papayae), which is reduced to synonymy under the former. Depazea nodorum (causal agent of nodorum blotch of cereals) and Septoria avenae (causal agent of avenae blotch of barley and rye) are placed in a new genus, Parastagonospora, which is shown to be distinct from Stagonospora (based on S. paludosa) and Phaeosphaeria. Partial nucleotide sequence data for five gene loci, ITS, LSU, EF-1a, RPB2 and Btub were generated for all of these isolates. A total of 47 clades or genera were resolved, leading to the introduction of 14 new genera, 36 new species, and 19 new combinations
    Diaporthe: a genus of endophytic, saprobic and plant pathogenic fungi
    Gomes, R.R. ; Glienke, C. ; Videira, S.I.R. ; Lombard, L. ; Groenewald, J.Z. ; Crous, P.W. - \ 2013
    Persoonia 31 (2013). - ISSN 0031-5850 - p. 1 - 41.
    internal transcribed spacer - south-africa - species concepts - sp-nov - coelomycete phomopsis - foeniculum-vulgare - multigene analysis - north-america - ribosomal dna - twig dieback
    Diaporthe (Phomopsis) species have often been reported as plant pathogens, non-pathogenic endophytes or saprobes, commonly isolated from a wide range of hosts. The primary aim of the present study was to resolve the taxonomy and phylogeny of a large collection of Diaporthe species occurring on diverse hosts, either as pathogens, saprobes, or as harmless endophytes. In the present study we investigated 243 isolates using multilocus DNA sequence data. Analyses of the rDNA internal transcribed spacer (ITS1, 5.8S, ITS2) region, and partial translation elongation factor 1-alpha (TEF1), beta-tubulin (TUB), histone H3 (HIS) and calmodulin (CAL) genes resolved 95 clades. Fifteen new species are described, namely Diaporthe arengae, D. brasiliensis, D. endophytica, D. hongkongensis, D. inconspicua, D. infecunda, D. mayteni, D. neoarctii, D. oxe, D. paranensis, D. pseudomangiferae, D. pseudophoenicicola, D. raonikayaporum, D. schini and D. terebinthifolii. A further 14 new combinations are introduced in Diaporthe, and D. anacardii is epitypified. Although species of Diaporthe have in the past chiefly been distinguished based on host association, results of this study confirm several taxa to have wide host ranges, suggesting that they move freely among hosts, frequently co-colonising diseased or dead tissue. In contrast, some plant pathogenic and endophytic taxa appear to be strictly host specific. Given this diverse ecological behaviour among members of Diaporthe, future species descriptions lacking molecular data (at least ITS and HIS or TUB) should be strongly discouraged.
    Abundance, distribution and population trends of Nile crocodile (Crocodylus niloticus) in Gonarezhou National Park, Zimbabwe
    Zisadza-Gandiwa, P. ; Gandiwa, E. ; Jakarasi, J. ; Westhuizen, H. van der; Muvengwi, J. - \ 2013
    Water SA 39 (2013)1. - ISSN 0378-4738 - p. 165 - 170.
    south-africa - olifants river - communities adjacent - okavango delta - conservation - botswana - impact - water
    The Nile crocodile (Crocodylus niloticus) is an iconic or keystone species in many aquatic ecosystems. In order to understand the abundance, distribution, and population trends of Nile crocodiles in Gonarezhou National Park (GNP), southeastern Zimbabwe, we carried out 4 annual aerial surveys, using a Super Cub aircraft, along 3 major rivers, namely, Save, Runde and Mwenezi, between 2008 and 2011. Our results show that Runde River was characterised by a significant increase in Nile crocodile abundance whereas both Save and Mwenezi rivers were characterised by non-significant increases in Nile crocodile abundance. Overall, we recorded a significant increase in total Nile crocodile population in the three major rivers of the GNP. The non-significant increase in Nile crocodiles in the Mwenezi and Save rivers was likely due to habitat loss, through siltation of large pools, and conflicts with humans, among other factors. We suggest that GNP management should consider halting crocodile egg collection in rivers with low crocodile populations and continuously monitor the crocodile population in the park
    Non-linear partial least square regression increases the estimation accuracy of grass nitrogen and phosphorus using in situ hyperspectral and environmental data
    Ramoelo, A. ; Skidmore, A.K. ; Cho, M.A. ; Mathieu, R. ; Heitkonig, I.M.A. ; Dudeni-Tlhone, N. ; Schlerf, M. ; Prins, H.H.T. - \ 2013
    ISPRS Journal of Photogrammetry and Remote Sensing 82 (2013). - ISSN 0924-2716 - p. 27 - 40.
    kruger-national-park - multiple linear-regression - band-depth analysis - vegetation indexes - south-africa - chlorophyll estimation - imaging spectroscopy - absorption features - biochemical content - mineral-nutrition
    Grass nitrogen (N) and phosphorus (P) concentrations are direct indicators of rangeland quality and provide imperative information for sound management of wildlife and livestock. It is challenging to estimate grass N and P concentrations using remote sensing in the savanna ecosystems. These areas are diverse and heterogeneous in soil and plant moisture, soil nutrients, grazing pressures, and human activities. The objective of the study is to test the performance of non-linear partial least squares regression (PLSR) for predicting grass N and P concentrations through integrating in situ hyperspectral remote sensing and environmental variables (climatic, edaphic and topographic). Data were collected along a land use gradient in the greater Kruger National Park region. The data consisted of: (i) in situ-measured hyperspectral spectra, (ii) environmental variables and measured grass N and P concentrations. The hyperspectral variables included published starch, N and protein spectral absorption features, red edge position, narrow-band indices such as simple ratio (SR) and normalized difference vegetation index (NDVI). The results of the non-linear PLSR were compared to those of conventional linear PLSR. Using non-linear PLSR, integrating in situ hyperspectral and environmental variables yielded the highest grass N and P estimation accuracy (R2 = 0.81, root mean square error (RMSE) = 0.08, and R2 = 0.80, RMSE = 0.03, respectively) as compared to using remote sensing variables only, and conventional PLSR. The study demonstrates the importance of an integrated modeling approach for estimating grass quality which is a crucial effort towards effective management and planning of protected and communal savanna ecosystems.
    Phyllosticta species on citrus: Risk estimation of resistance to QoI fungicides and identification of species with cytochrome b gene sequences
    Stammler, G. ; Schutte, G.C. ; Speakman, J. ; Miessner, S. ; Crous, P.W. - \ 2013
    Crop Protection 48 (2013). - ISSN 0261-2194 - p. 6 - 12.
    guignardia-citricarpa - black spot - botrytis-cinerea - south-africa - mitochondrial-dna - pyrenophora-teres - valencia oranges - f129l mutation - causal agent - mangiferae
    Isolates of three fungal species associated with citrus, Phyllosticta citricarpa, Phyllosticta citriasiana and Phyllosticta capitalensis, collected from different citrus growing countries of the world, were investigated for their sensitivities to the QoI fungicides pyraclostrobin and azoxystrobin. Isolates were highly sensitive in microtiter tests and EC50 values were in narrow ranges, which indicate no acquired adaptation to QoIs. The resistance risk of P. citricarpa to QoIs is considered low since an intron was found immediately after codon 143 in the cytochrome b gene. The presence of an intron is known to reduce the risk of the G143A mutation, the mutation which causes QoI resistance with high resistance factors. The other two species had no intron and therefore are considered having a higher resistance risk. Impact of these two species is rather low, since P. citriasiana is restricted in its regional and host distribution and P. capitalensis is non-pathogenic. Furthermore, the development of a rapid and reliable assay for species detection and identification was made possible based on an analysis of the cytochrome b gene.
    Illegal hunting and law enforcement during a period of economic decline in Zimbabwe: A case study of northern Gonarezhou National Park and adjacent areas
    Gandiwa, E. ; Heitkonig, I.M.A. ; Lokhorst, A.M. ; Prins, H.H.T. ; Leeuwis, C. - \ 2013
    Journal for Nature Conservation 21 (2013)3. - ISSN 1617-1381 - p. 133 - 142.
    protected areas - communities adjacent - central-africa - wildlife consumption - equatorial-guinea - western serengeti - nature-reserves - luangwa valley - local people - south-africa
    Illegal hunting of wildlife, or top-down harvesting, is a major issue in today's society, particularly in tropical ecosystems. There has been widespread concern about increasing illegal hunting of wildlife in most conservation areas in Zimbabwe following the political instability and economic decline the country faced since 2000. In this study, we focused on the northern Gonarezhou National Park (GNP), a large and unfenced protected area, and adjacent communal areas in southern Zimbabwe. We hypothesised that illegal hunting activities would (1) be perceived to have increased due to economic collapse and (2) vary with law enforcement efforts. A total of 236 local residents from eight villages adjacent to the northern GNP were interviewed using semi-structured questionnaires from December 2010 to May 2011, and law enforcement data for northern GNP between 2000 and 2010 were retrieved from the park law enforcement database. A total of 26 animal species were reportedly hunted. Bushmeat consumption and the need for local trade to raise income were reported as the main reasons behind illegal hunting. Contrary to the first hypothesis, the majority of respondents (n = 156, 66%) reported that illegal hunting activities had declined between 2000 and 2010 largely due to increased park protection as also supported by law enforcement data. A total of 22 animal species were recorded as having been illegally hunted in northern GNP. The number of illegal hunters arrested declined with increased law enforcement efforts although the number of wire snares recovered and hunting dogs shot appeared to increase following increased law enforcement efforts. These results partly support the second hypothesis that illegal hunting activities would vary with law enforcement efforts
    Optimization of wildlife management in a large game reserve through waterpoints manipulation: a bio-economic analysis
    Mwakiwa, E. ; Boer, W.F. de; Hearne, J.W. ; Slotow, R. ; Langevelde, F. van; Peel, M. ; Grant, C.C. ; Pretorius, Y. ; Stigter, J.D. ; Skidmore, A.K. ; Heitkonig, I.M.A. ; Knegt, H.J. de; Kohi, E. ; Knox, N. ; Prins, H.H.T. - \ 2013
    Journal of Environmental Management 114 (2013). - ISSN 0301-4797 - p. 352 - 361.
    kruger-national-park - surface-water availability - south-africa - herbaceous vegetation - elephants - provision - impact - conservation - biodiversity - systems
    Surface water is one of the constraining resources for herbivore populations in semi-arid regions. Artificial waterpoints are constructed by wildlife managers to supplement natural water supplies, to support herbivore populations. The aim of this paper is to analyse how a landowner may realize his ecological and economic goals by manipulating waterpoints for the management of an elephant population, a water-dependent species in the presence of water-independent species. We develop a theoretical bio-economic framework to analyse the optimization of wildlife management objectives (in this case revenue generation from both consumptive and non-consumptive use and biodiversity conservation), using waterpoint construction as a control variable. The model provides a bio-economic framework for analysing optimization problems where a control has direct effects on one herbivore species but indirect effects on the other. A landowner may be interested only in maximization of profits either from elephant offtake and/or tourism revenue, ignoring the negative effects that could be brought about by elephants to biodiversity. If the landowner does not take the indirect effects of waterpoints into consideration, then the game reserve management, as the authority entrusted with the sustainable management of the game reserve, might use economic instruments such as subsidies or taxes to the landowners to enforce sound waterpoint management.
    Manage or convert Boswellia woodlands? Can frankincense production payoff?
    Dejene, T. ; Lemenih, M. ; Bongers, F. - \ 2013
    Journal of Arid Environments 89 (2013). - ISSN 0140-1963 - p. 77 - 83.
    forest products - south-africa - dry forests - papyrifera - ethiopia - environment - zimbabwe - trade
    African dry forests provide non-timber forest products (NTFPs) of high commercial value, such as frankincense and gum arabic. Nonetheless, their deforestation and conversion to croplands is intensifying. Expected higher financial return from crop production is a main driver of conversion, but research supporting this underlying claim is scarce. We compared the financial returns for two crop production options (sesame and cotton) and forest use, in a dry forest area known for its frankincense production in northern Ethiopia. Net revenue was highest for sesame and lowest for cotton agricultural use. The forest based revenue was intermediate. The revenues from the crop production options were more sensitive to a range of uncertainties than the forest land use. Our results show that forest land use that includes commercial NTFPs is financially competitive to some commercial crop options and offers returns of better reliability. The hypothesis that forest based revenues are lower than crop based ones is not supported by our results. Therefore, the continued deforestation of dry forests cannot be explained by lower returns alone, but other factors such as awareness, market access, property right and institutional issues may also play a role to drive deforestation and conversion of dry forests to croplands.
    The Meaning of Adherence When Behavioral Risk Patterns Vary: Obscured Use- and Method-Effectiveness in HIV-Prevention Trials
    Bruin, M. de; Viechtbauer, W. - \ 2012
    PLoS ONE 7 (2012)8. - ISSN 1932-6203
    sexual-behavior - south-africa - male circumcision - infection - metaanalysis - women - men - prevalence - challenges - efficacy
    Background Recently promising trials of innovative biomedical approaches to prevent HIV transmission have been reported. Participants' non-adherence to the prevention methods complicates the analyses and interpretation of trial results. The influence of variable sexual behaviors within and between participants of trials further obscures matters. Current methodological and statistical approaches in HIV-prevention studies, as well as ongoing debates on contradictory trial results, may fail to accurately address these topics. Methodology/Principal Findings Through developing a cumulative probability model of infection within HIV prevention trials, we demonstrate how adherence and sexual behavior patterns impact the overall estimate of effectiveness, the effectiveness of prevention methods as a function of adherence, and conclusions about methods' true effectiveness. Applying the model to summary-level data from the CAPRISA trial, we observe markedly different values for the true method effectiveness of the microbicide, and show that if the gel would have been tested among women with slightly different sexual behavior patterns, conclusions might well have been that the gel is not effective. Conclusions/Significance Relative risk and adherence analyses in HIV prevention trials overlook the complex interplay between adherence and sexual behavior patterns. Consequently, they may not provide accurate estimates of use- and method-effectiveness. Moreover, trial conclusions are contingent upon the predominant sexual behavior pattern of participants and cannot be directly generalized to other contexts. We recommend researchers to (re)examine their data and use the cumulative probability model to estimate the true method effectiveness, which might contribute to resolving current questions about contradictory trial results. Moreover, we suggest taking into account the issues raised in the design of future trials and in population models estimating the impact of large-scale dissemination of prevention methods. Comprehension of the topics described will help readers to better interpret (apparently contradictory) trial outcomes.
    Rural Poverty Dynamics in Kenya: Structural Declines and Stochastic Escapes
    Radeny, M.A.O. ; Berg, M.M. van den; Schipper, R.A. - \ 2012
    World Development 40 (2012)8. - ISSN 0305-750X - p. 1577 - 1593.
    south-africa - household poverty - 36 villages - poor - countries - growth - uganda - traps - india - time
    We use panel survey data and household event-histories to explore patterns of rural poverty dynamics in Kenya over the period 2000–2009. We find substantial mobility across poverty categories using economic transition matrices. Drawing on asset-based approaches, we distinguish stochastic from structural poverty transitions. Few households successfully escaped poverty through asset accumulation (up to 35% of the upwardly mobile), while a large proportion of households (up to 66%) declining into poverty experienced structural transitions. Using household event-histories, we find significant differences across structural poverty transition classes in livelihood strategies, household-level shocks, and other factors.
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