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Sustainable Utilization (sustainable + utilization)
Selected AbstractsPlant harvest impacts and sustainability in Bwindi Impenetrable National Park, S.W. UgandaAFRICAN JOURNAL OF ECOLOGY, Issue 1 2006Robert Bitariho Abstract Sustainable utilization of forest resources has been widely adopted as a conservation strategy, but that sustainability has rarely been empirically tested. Plant resource extraction from Bwindi Impenetrable National Park (BINP) by local communities has been legalized and controlled in areas called multiple use zones (MUZs). Through a series of systematic transects and plots, we determined harvest impacts of two mostly harvested medicinal plants of Rytigynia kigeziensis VERDC.l and Ocotea usambarensis Engl in BINP. The plots were placed in MUZs and non-MUZs. Data on biomass production and population dynamics were collected from the plots. We also analysed forest society records for the past 3 years to determine annual plant resource offtakes from BINP. Bark production of the two plants in MUZs and non-MUZs are not significantly different, suggesting an insignificant change in bark production because of bark harvest. Annual bark harvests of the two plants are between 0.26,1.64% of available bark stock. These are too low to cause any noticeable negative impacts and are sustainable. Annual bark harvest of R. kigeziensis and O. usambarensis should be increased from the original 1% to about 3% of available bark stock to allow more involvement of the marginalized poor people like Batwa in BINP. Résumé L'usage viable des ressources forestières a été largement adopté comme stratégie de conservation, mais cette viabilité n'a que rarement été enquêté empiriquement. L'extraction de ressources végétales du Parc National Impénétrable de Bwindi (BINP) par les communautés locales a été légalisée et contrôlée dans des zones appelées ,les zones d'usage multiple' (les MUZ). A travers une série de transectes et placettes systématiques, nous avons déterminé l'impact de la récolte de deux plantes médicinale Rytigynia kigeziensis VERDC.l et Ocotea usambarensis Engl dans le BINP. Les placettes furent situées dans des MUZ ainsi que dans les nons-MUZ. Les données sur la production de biomasse et les dynamiques de la population furent ramassées des placettes. Nous avons analyséaussi les archives de la Société Forestière sur les trois dernières années afin de déterminer le niveau d'enlèvement des ressources végétales dans le BINP. La production d'écorce des deux plantes ne variait pas significativement dans des zones MUZ par rapport aux non-MUZ, ce qui suggère que la rècolte de l'écorce n,agit pratiquement pas sur la production de l'écorce. La rècolte annuelle des plantes représente de 0.26 à 1.64% des réserves d'écorce disponibles. Ces chiffres sont trop petits pour provoquer des dègâts perceptibles et sont viables. La récolte annuelle de R. kigeziensis et O. usambarensis devrait être augmentée à 3% des réserves d'écorce (de 1% actuellement) afin de permettre aux gens marginalisès et pauvres dans le BINP, tel Batwa, d'avoir une plus grande participation. [source] Predicting time-specific changes in demographic processes using remote-sensing dataJOURNAL OF APPLIED ECOLOGY, Issue 2 2006HENRIK B. RASMUSSEN Summary 1Models of wildlife population dynamics are crucial for sustainable utilization and management strategies. Fluctuating ecological conditions are often key factors influencing both carrying capacity, mortality and reproductive rates in ungulates. To be reliable, demographic models should preferably rely on easily obtainable variables that are directly linked to the ecological processes regulating a population. 2We compared the explanatory power of rainfall, a commonly used proxy for variability in ecological conditions, with normalized differential vegetation index (NDVI), a remote-sensing index value that is a more direct measure of vegetation productivity, to predict time-specific conception rates of an elephant population in northern Kenya. Season-specific conception rates were correlated with both quality measures. However, generalized linear logistic models compared using Akaike's information criteria showed that a model based on the NDVI measure outperformed models based on rainfall measures. 3A predictive model based on coarse demographic data and the maximum seasonal NDVI value was able to trace the large variation in observed season-specific conception rates (Range 0,0·4), with a low median deviation from observed values of 0·07. 4By combining the model of season-specific conception rates with the average seasonal distribution of conception dates, the monthly number of conceptions (range 0,22) could be predicted within ±3 with 80% confidence. 5Synthesis and applications. The strong predictive power of the normalized differential vegetation index on time-specific variation in a demographic variable is likely to be generally applicable to resource-limited ungulate species occurring in ecologically variable ecosystems, and could potentially be a powerful factor in demographic population modelling. [source] Forage production and plant diversity in two managed rangelands in the Main Ethiopian RiftAFRICAN JOURNAL OF ECOLOGY, Issue 1 2010Ali Seid Mohammed Abstract The purpose of this study was to investigate the floristic diversity and productivity of managed rangelands in the Main Ethiopian Rift (MER). The relationships between forage production and plant diversity among four native range sites (i.e. Alagae hay-field, Alagae woodland, Neteli hay-field and Neteli woodland) that were different in range condition were examined. The major variables studied include floristic diversity, herbaceous biomass production and range condition assessment. A total of 213 species, representing 143 genera and 40 families, were identified from the study sites. The range conditions ranked from poor to good. Herbaceous biomass production followed a quadratic relationship with range condition. The humpback model was tested and found to be applicable to the MER rangelands. The study results reflect on the need for optimizing productivity and biodiversity conservation and put emphasis on the need for integrating agricultural production and biodiversity conservation interests for the sustainable utilization of rangelands. Résumé L'objectif de cette étude était d'étudier la diversité floristique et la productivité de pâturages gérés dans le Rift éthiopien principal (REP). La relation entre la production de fourrage et la diversité de plantes dans quatre sites indigènes dont les conditions étaient différentes (à savoir : prairie à faucher d'Alagae, forêt d'Alagae, prairie de Neteli et forêt de Neteli) ont été examinées. Les principales variables étudiées comprennent la diversité floristique, la production de biomasse herbacée et l'évaluation des conditions de la région. Un total de 213 espèces appartenant à 143 genres et à 40 familles ont été identifiées sur les sites de l'étude. Les conditions de la région variaient de médiocre à bonne. La production de biomasse herbacée suivait une relation quadratique avec les conditions de la région. Le modèle « épaulard » (Humpback model) a été testé et l'on a trouvé qu'il pouvait s'appliquer aux pâturages REP. Les résultats de l'étude se reflètent dans le besoin d'optimiser la productivité et la conservation de la biodiversité, et mettent l'accent sur la nécessité d'intégrer les intérêts de la production agricole et de la conservation de la biodiversité pour arriver à une utilisation durable des pâturages. [source] Biology and establishment of mountain shrubs on mining disturbances in the Rocky Mountains, USALAND DEGRADATION AND DEVELOPMENT, Issue 5 2003M. W. Paschke Abstract The Rocky Mountains of the western United States contain many economically important natural resources. Increasing development of these resources has lead to land degradation, which often requires restoration efforts. A common type of disturbance in this region is mineral extraction and these activities often occur in zones of vegetation dominated by shrubs. These mined lands have proven to be particularly challenging to restore to native shrub cover. Mountain shrubland species such as big sagebrush (Artemisia tridentata), antelope bitterbrush (Purshia tridentata), Saskatoon serviceberry (Amelanchier alnifolia), black chokecherry (Prunus virginiana), mountain mahogany (Cercocarpus montanus), and snowberry (Symphoricarpos sp.) are crucial species for wildlife in this region due to the seasonal dependence of many wildlife species on the mountain shrubland zones. The development of successful restoration techniques for these key shrub species is therefore important for the continued and sustainable utilization of natural resources in the Rocky Mountains. The purpose of this literature review is to provide a reference to land managers working on woody plant establishment on mining disturbances in mountain shrublands in the Rocky Mountains. This review covers the biology, ecology, and propagation of six shrub species that are of primary importance for meeting regulatory compliance in this region. Based upon this survey of the published literature, we conclude that successful establishment of these species has most often involved: (1) utilization of local shrub ecotypes, varieties or subspecies in reclamation efforts, (2) protection from browsing during the establishment phase, (3) strategies for avoiding herbaceous competition, and (4) providing a source of mutualistic soil organisms. Additional specific recommendations for each of these species are discussed. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||