Endoscopic sex determination and gonadal manipulation in Gulf of Mexico sturgeon (Acipenser oxyrinchus desotoi).

Seventeen Gulf of Mexico sturgeons (Acipenser oxyrinchus desotoi) underwent endoscopic sex determination, gonadal biopsy, and various reproductive surgeries as part of a conservation development plan. The fish were anesthetized with tricaine methanesulfonate (MS-222) buffered with sodium bicarbonate and maintained on a recirculating water anesthesia circuit. A 6-mm Ternamian EndoTip Cannula, placed through the ventral midline, midway between pectoral and pelvic fins, permitted the introduction of a 5-mm telescope. Swim bladder aspiration and CO2 insufflation of the coelomic cavity provided excellent observation. Second and third cannulae were placed under direct visual control, lateral and cranial or caudal to the telescope cannula. Sex determination was successfully performed in all fish; however, five of 17 sturgeons (29%) required endoscopic gonadal biopsy to confirm sex. Bilateral ovariectomy or orchidectomy was successfully performed in three males and four females. Unilateral ovariectomy and bilateral ligation of the müllerian ducts using an extracorporeal suturing technique was accomplished in an additional three females. No apparent morbidity was associated with the anesthesia or endoscopic surgery in any fish. The ability to safely perform minimally invasive reproductive surgery in fish may have important management and conservation benefits.     

Contrasting Preference for Grassland Landscapes Among Population Groups in the Central and Southern Great Plains

Recent opposition to the rangeland management paradigm of achieving uniform, moderate grazing across entire landscapes has emerged because heterogeneity is recognized as the foundation of biodiversity, ecosystem resilience, and multifunctionality of agricultural landscapes. Agriculture production goals appear to drive the traditional rangeland management focus on homogeneity and uniformity. To determine if preference for homogeneity is a broadly applicable social construct or one limited to agricultural producers, we determined preferences for heterogeneous grassland landscapes expressed by three study populations—managers of working lands (ranchers), natural resource professionals (grassland/rangeland specialists), and the general population living in rangeland regions within the US Great Plains. We distributed surveys that included photographs of landscapes and patterned images to assess preference. Preference for heterogeneous landscapes among ranchers, natural resource professionals, and the general population in our study area were generally consistent with the central paradigm of managing rangeland for homogeneity. However, we discovered that people, across geographic location and population group, clearly prefer heterogeneous patterned images to homogeneous patterned images. This suggests that preference for homogeneity is acquired.     

Risk factors associated with occurrence of nematodes in free range pigs in Busia District,Kenya

Nematode infections are a serious constraint to pig production, especially where free range pig keeping is practiced. This study investigated the epidemiology of nematodes in free range pigs in Busia District, Kenya. Three hundred and six pigs from 135 farms were sampled for faeces that were analysed for nematode eggs per gram (EPG) of faeces using the McMaster technique. The nematode eggs were also identified to genus and species based on morphology. A questionnaire on risk factors was also administered to the pig owners. The overall prevalence and mean nematode EPG were 84.2% and 2,355, respectively. The nematode eggs were identified as those belonging to Oesophagostomum spp. (75%), Strongyloides ransomi (37%), Ascaris suum (18%), Metastrongylus spp. (11%), Trichuris suis (7%) and Physocephalus sexalatus (3%). The prevalence of nematodes was positively correlated (p < 0.05) with the amount of rainfall in the division of the pigs' origin (all nematodes except S. ransomi). The prevalence of nematodes was also associated with the age of the pigs. A lower burden of nematodes was associated (p < 0.05) with a history of deworming (A. suum) and the provision of night housing (S. ransomi and Metastrongylus spp.). In conclusion, this study has provided information on nematode infections and the associated risk factors for free range pigs in Busia District, which can be used when implementing integrated control measures.     

Tree planting for poverty reduction in less-favoured areas of the Ethiopian highlands

This paper assesses the potential impact of planting of eucalypt trees as a strategy to reduce poverty in a less-favoured area of the highlands of Ethiopia. Results from simulations with a bio-economic model for a less-favoured case study area in the highlands are combined with survey data at community, household and plot level to assess how general the results of the bio-economic model are. Application of the bio-economic model shows clearly that land degradation, population growth, stagnant technology and drought threaten food security. Household welfare and land quality are deteriorating rapidly in the area and interventions are urgently needed to avoid human disaster. Planting of eucalypts on land unsuitable for crop production may substantially increase household incomes if market outlets for trees can be found. Tree planting will not have severe negative effects on food production or land conservation. A policy combining promotion of tree planting and conservation of cropland may achieve win-win benefits in terms of increased household incomes as well as more sustainable land-use. Analysis of survey data from the Amhara Region of Ethiopia reveals that there is a large area of land that is unsuitable for crop production located close to all-weather roads in the less-favoured areas of the region. Few trees have been planted on this type of land up to now. The past policy seems to have discouraged tree planting except on homestead plots that are more suitable for food crops. This paper reports part of the IFPRI/ILRI project ‘Policies for Sustainable Land Management in the East African Highlands’. These two agencies have provided funds and logistical support for the work. The Norwegian Ministry of Foreign Affairs has provided funds for this research in the Amhara Region in Ethiopia. The authors also draw on earlier work funded by Research Council of Norway. Any correspondence should be directed to the first author.     

An explicit stem profile model for forked and un-forked teak (Tectona grandis) trees in West Africa

Studies on stem profile of teak (Tectona grandis) hardly exist. This can be possibly attributed to the occurrence of forks that is prevalent on teak trees. Stem profile model was therefore developed for teak in West Africa, which took into account the occurrence of forks. Trees were destructively sampled from Moist Evergreen Forest (MEF), Moist Semi-deciduous Forest (MSDF), Dry Semi-deciduous Forest (DSDF) and Savannah ecological zones in both Ghana and Côte d’Ivoire for the study. A single set of parameters could be used explicitly to predict stem profile of any teak tree, irrespective of country, eco-climatic zone, edaphic variables, site index, tree age, stand density and tree competition. The model efficiency and root mean square error (in relative diameter) were calculated to be 0.97 and 0.053, respectively. The relative position of the forks along the stem bole, with respect to total tree height, was highly variable and did not follow any particular trend, except higher value for the first fork in the Moist Evergreen Forest zone. However, average tree height to the first fork decreased along the ecological gradient from MEF, MSDF and DSDF to Savannah. The extent of diameter reduction due to the forks could be predicted. Relative tree form for zero-forked, one-forked and two-forked trees was calculated to be 0.39, 0.36 and 0.33, respectively. Relative loss of stem volume due to one fork and two forks was estimated to be 6.5 and 13.9%, respectively. The measured stem volume when related to the corresponding predicted value yielded coefficient and intercept not significantly different from unity and zero, respectively, with an r² value of 0.97.     

Arthropod diversity of cocoa farms under two management systems in the Eastern and Central regions of Ghana

Diversity of insect communities can be used as bioindicators for change in the environment especially in farms under different management systems. In line with that, we conducted a research on insect species associated with cocoa under organic and conventional management systems in the Eastern and Central regions of Ghana. Insect collection was done using Hand height visual count, Canopy, and “Knock down”, pitfall, coloured bowl and fruit-baited traps. A total of 13,742 individual insects belonging to 138 species from 63 families and 12 orders were recorded in the study. Insect abundance and diversity were generally higher in organic farms compared to conventional farms with Oecophylla longinoda as the most dominant species in both management systems and especially more dominant in organic cocoa farms. Our study revealed that most of the insect species recorded were known cocoa pests although there was high abundance of beneficial insects too. Some of the pest species were Planococoides njalensis, Salhbergella singularis, Helopeltis spp and Pseudococus spp, while some of the beneficial insects recorded were Pheidole spp, Tegenaria spp, Camponotus spp, Crematogaster spp. We can conclude that cocoa farms are potential habitats for insect biodiversity conservation. We recommend that management and/or agronomic practices used in cocoa farms should be geared towards protecting beneficial organisms for instance pollinators and natural enemies by effectively suppressing insect pest populations while enhancing good seed production.