An ethnomedicinal study was conducted to document the indigenous medicinal plant knowledge and use by traditional healers in southwestern Ethiopia from December 2005 to November 2006. Data were ...collected from 45 randomly selected traditional healers using semi-structured interviews and observations. Sixty-seven ethnomedicinal plant species used by traditional healers to manage 51 different human ailments were identified and documented. Healers' indigenous knowledge was positively correlated with their reported age but not with their educational level. High degree of consensus was observed among traditional healers in treating tumor (locally known as Tanacha), rabies (Dhukuba Seree) and insect bite (Hadhaa). The use of more than one species was significantly cited for remedy preparations. The reported abundance of the ethnomedicinal plant species varied significantly with respect to the presence of multiple uses of the reported species. Our results showed that ethnomedicinal plant species used by healers are under serious threat due to several factors, which indicates the need for urgent attention towards their conservation and sustainable utilization.
Cassia abbreviata and Senegalia nigrescens are indigenous trees found in North and Central regions of Botswana. However, inadequate knowledge of their silviculture and decline in population due to ...deforestation, expanding settlements, infrastructure and agriculture are major threats to most indigenous tree species in Botswana. Like many indigenous tree species, Cassia abbreviata and Senegalia nigrescens are slow-growing and are threatened by overexploitation for numerous uses. Because of the increased demand for medicinal uses, medicinal species such Cassia abbreviata are rapidly disappearing in many habitats and threatened to extinction. This study assessed the response of pre-sowing treatment methods on quiescency and germination of seeds of Cassia abbreviata and Senegalia nigrescens tree species found in semiarid Savanna Ecozone of Botswana. Pre-sowing treatment included immersion in 98% undiluted sulfuric acid (H2SO4) for 15, 30, 45 and 60 minutes, submergence in boiling water for one, two, three minutes and submerged in warm water for 24 hours, mechanical scarification of the seed coat and control. ANOVA showed that there is a highly significant difference (P < 0.0001) among the treatments of C. abbreviata in seed germination and no significant difference among the treatments of S. nigrescens. The highest germination percentage of C. abbreviata seeds was 81%, which was found from seeds immersed in H2SO4 for 30 minutes, while for S. nigrescens seeds, the highest germination percentage was 99%, which was found from seeds treated with mechanical scarification and those immersed in H2SO4 for 15 and 45 minutes. The objective of this study is to determine the effect of pretreatment methods on germination of C. abbreviata and S. nigrescens seeds. Based on these results, we recommend sulphuric acid and mechanical scarification as suitable seed pre-sowing treatments for enhancing the germination of C. abbreviata and S. nigrescens, respectively.
Monitoring urban growth patterns is an important measure to improve our understanding of land use/land cover (LULC) changes and a central part in the proper development of any city. In this study, we ...analyzed the changes over a period of 30 years (1985–2015) in Bahir Dar, one of the rapidly growing cities of northwest Ethiopia. Satellite images of Landsat TM (1985, 1995, and 2008), and OLI (2015) were used. The classification was carried out using the object-based image analysis technique and a change analysis was undertaken using post-classification comparison in GIS as a novel framework. An accuracy assessment was conducted for each reference year. Eight LULC types were successfully captured with overall accuracies ranging from 88.3% to 92.9% and a Kappa statistic of 0.85 to 0.92. The classification result revealed that cropland (66%), water (12.5%), and grassland (6%) were the dominant LULC types with a small share of areas covered by built-up areas (2.4%) in 1985. In 2015, cropland and water continued to be dominant followed by built-up areas. The change result shows that a rapid reduction in natural forest cover followed by grassland and wetland occurred between the first (1985–1995), second (1995–2008), and third (2008–2015) study periods. On the contrary, build-ups increased in all three periods by 9.3%, 121.3%, and 44.8%, respectively. Although the conversion between the LULC classes varied substantially, analysis of the 30-year change matrix revealed that about 31% was subject to intensive change between the classes. Specifically, the built-up area has increased by 250.5% during the study years. The framed approach used in this research is a good repeatable example of how to assess and monitor urban growth at the local level, by combining remote sensing and GIS technologies. Further study is suggested to investigate detailed drivers, consequences of changes, and future options.
Introduction
An area exclosure is the practice of land management that involves the exclusion of livestock and humans from openly accessing an area that is characterized by severe degradation. Area ...exclosures have been employed as cheap and convenient means of rehabilitating degraded forests/woodlands. A study was carried out to (i) assess the species richness, diversity and evenness; (ii) determine the densities, frequencies, dominance and importance value index; and (iii) assess the population structure and regeneration status of woody species inside and outside the fence (area exclosure) of Okavango Research Institute (ORI) located in Maun, northern Botswana.
Results
Thirty-five woody species were recorded inside (32 spp.) and outside (24 spp.) the ORI compound, and the population structure and regeneration status of the woody species were better inside than outside the ORI compound. The exclosure had seven times higher mean density of woody species than outside ORI, and an exceptional regeneration of seedlings was observed inside than outside the ORI compound, suggesting the process of recovery of the degraded woodland. The frequencies of more than half of the woody species also showed increment inside than outside the exclosure. The results suggest that the exclosed area is still in an initial recovery stage since it had been an open grazing area prior to the establishment of the exclosure. Most of the woody species encountered outside ORI showed hampered recruitment and regeneration, owing to different anthropogenic impacts and overgrazing by animals.
Conclusions
Despite the relatively short period (10 years) of exclosure establishment, results from the present study have further provided empirical evidences on the actual crucial roles played by area exclosures to increase woody species richness, diversity, evenness, density, frequency, dominance and important value index as well as enhance the population structure and regeneration of the woody species in northern Botswana. Future research is recommended focusing on comparative studies on herbaceous species richness, diversity and density, horizontal and vertical distribution of soil seed banks, species richness of soil microorganisms, plant and soil biomass, plant and soil carbon pools (above and below ground) as well as soil contents and properties inside and outside the ORI compound.
Tree growing by smallholder farmers is an emerging livelihood strategy in Lake Tana catchment. The objectives of this study were to (1) identify the most important tree species grown, (2) investigate ...the drivers of the existing pattern, and (3) identify determinants of the number and diversity of tree species and their spatial patterns. Survey data were collected from 200 households. Multiple linear regression was employed to identify the determinants of tree growing behaviour of households and spatial variables affecting the abundance of tree species. Eucalyptus globulus, Acacia decurrens and E. camaldulensis dominate woodlots. Only a fraction of the forest production is used by the households, the rest being sold as poles or charcoal. Location in relation to market centres, number of livestock owned, landholding size and age of household head were found to positively affected the number of tree species and trees grown. Gender affected the species and spatial pattern of trees. Woodlots, farm boundaries and homesteads were found to be important tree growing niches. These results substantiate the proposition that farmers assign their parcels of land to uses that increase the rent value of the land, and this value is affected by access to roads. Woodlots are on the increase at the cost of productive agricultural land. Provision of a tree planting extension service may increase participation of farmers in tree planting, and a management-oriented tree planting extension service may give desirable results.
The trend of land cover (LC) and land cover change (LCC), both in time and space, was investigated at the Simen Mountains National Park (SMNP), a World Heritage Site located in northern Ethiopia, ...between 1984 and 2003 using Geographical Information System (GIS) and remote sensing (RS). The objective of the study was to generate spatially and temporally quantified information on land cover dynamics, providing the basis for policy/decision makers and resource managers to facilitate biodiversity conservation, including wild animals. Two satellite images (Landsat TM of 1984 and Landsat ETM+ of 2003) were acquired and supervised classification was used to categorize LC types. Ground Control Points were obtained in field condition for georeferencing and accuracy assessment. The results showed an increase in the areas of pure forest (Erica species dominated) and shrubland but a decrease in the area of agricultural land over the 20 years. The overall accuracy and the Kappa value of classification results were 88 and 85%, respectively. The spatial setting of the LC classes was heterogeneous and resulted from the biophysical nature of SMNP and anthropogenic activities. Further studies are suggested to evaluate the existing LC and LCC in connection with wildlife habitat, conservation and management of SMNP.
•The results revealed that the Thamalakane riparian woodlands (TRWs) possess large quantities of buried seeds of herbs, grasses, sedges and a few woody species in the soil. The herbaceous species in ...the soil seed banks of TRWs were dominant.•The overall horizontal distribution of seeds varied among sampling quadrats while the vertical distribution of seeds exhibited the highest densities occurring in the upper three centimeters of soil and gradually decreasing densities with increasing depth. Relatively high densities also occurred in the litter layer.•The similarity in species composition between the soil seed flora and standing vegetation was low, since few woody species were represented in the soil seed bank. Therefore, the future of the TRW woody flora seems to depend on the successful conservation of the standing vegetation.•There were some exotic plants species that were encountered in the soil seed bank, seven herbaceous and one woody species.
Soil seed banks serve as reservoirs of seeds for subsequent regeneration of plants. Soil seed banks were investigated along the Thamalakane Riparian Woodlands (hereafter referred to as TRWs) of the Okavango Delta, northern Botswana, from January-July 2015 and January-July 2016. The study aimed at examining species richness and diversity, determining densities, assessing the spatial distribution of seeds in the soil and comparing the similarity in species composition between the standing vegetation and soil seed bank flora. The vegetation was sampled in 71 plots (20 × 50 m) and soil samples were collected from 568 subplots. Agglomerative hierarchical cluster analysis was used to determine soil seed bank communities. Indicator species analysis was used to calculate indicator values for species in each community of germinated seeds and across different soil layers. Multi-response permutation procedures (MRPP) were used to compare similarity in soil seed bank composition. Bray-Curtis ordination was used to infer spatial relationships of soil layers in terms of soil seed bank composition. A total of 109 plant species were identified in the litter and top 9 cm soil layers with a mean density of 2101 seeds m−2. Herbs, grasses, sedges and woody plants were represented by 68, 19, 9 and 13 species, respectively, in 30 families and 87 genera. The overall total diversity and evenness of the soil seed bank in the TRWs was 3.25 and 0.69, respectively. Four plant communities were identified from the soil seed bank, namely Setaria verticilata-Amaranthus hybridus, Acanthospermum hispidum-Setaria sagittifolia, Digitaria eriantha-Eclipta prostrata and Cyperus longus-Fimbristylis dichotoma. Bray-Curtis ordination showed that there was overlap between these communities in terms of seed bank composition. However, MRPP analysis showed that there was significant (P < 0.05) separation between germinated soil seed bank communities. The overall horizontal distribution of seeds varied among sampling quadrats while the vertical distribution of seeds exhibited the highest densities occurring in the upper 3 cm of the soil and gradually decreasing densities with increasing depth. Relatively high densities also occurred in the litter layer. There were large differences in depth distribution between species, suggesting differences in seed longevity. The similarity in species composition between the soil seed flora and standing vegetation was low (27%). The results demonstrated that many species in TRWs store quantities of seeds in the soil. The fact that most of the woody species do not accumulate more seeds in the soil suggests that their regeneration from seeds would be unlikely if mature individuals disappeared (die or are harvested). Because of its diverse seed banks, the herbaceous flora would have a better chance of re-establishing in the event of anthropogenic or natural disturbances. Therefore, the future of the TRW woody flora seems to depend on the successful conservation of the standing vegetation.
Background:Seed production,seed dispersal and seedling establishment are relevant life phases of plants.Understanding these processes and their patterns is essential to recognize vegetation dynamics ...and to apply it to forest restoration.Methods:For Olea europaea and Schefflera abyssinica,fecundity was estimated using randomized branch sampling.Seed dispersal and seedling establishment were monitored using spatially explicit seed traps and plots.Dispersal functions were calibrated applying inverse modeling.Results:O.europaea produced more seeds and had longer dispersal distances compared to S.abyssinica.Correlations between observed and predicted number of recruits were statistically significant.Seedlings of the two species showed different niche requirements.Conclusions:The studied species were recruitment-limited due to low dispersal activity or lack of suitable microsites.Restoration relying on natural regeneration should overcome these limitations by increasing disperser visitation and reducing biotic and abiotic stresses.
•The majority of respondents know about the medicinal value of Moringa oleifera.•Different parts of the plant are used to treat, mainly, diabetes, high blood pressure and rheumatism.•The trees do not ...need intensive management, establish easily, adapt to the arid climate of Botswana and grow with minimal care.•There is a big potential to expand and commercialize Moringa in Botswana if people are made aware of its benefits.•Given the potential food and non-food applications of Moringa, there is an urgent need to promote its cultivation and utilization so that it can contribute its share in Government efforts to ensure food security in Botswana.
A survey was conducted to document the history of introduction of Moringa oleifera, its current uses as well as potential for expansion and commercialization in Botswana. The study was conducted between February and December 2018 in Gaborone by interviewing a total of 20 households who have planted trees of Moringa in their backyards. A semi-structured questionnaire was developed, field tested, revised based on the feedback from the field test, and used for the interview. The results showed that the species was introduced to Botswana relatively recently, and most of the respondents started growing the trees in the last five years. The majority of the respondents (80%) are familiar with the Moringa plant, and 90% of them know about its medicinal values for which they planted the trees. However, there seems to be limited knowledge about the nutritional value of the species among the respondents. Different parts of the tree are used to treat, mainly, diabetes, high blood pressure and rheumatism. The leaves are used to treat most of these ailments although the seeds, stems, bark, roots and fruits have also been reported to have medicinal values. Some of the respondents indicated that they use the raw or boiled leaves as vegetable, and prepare soup and stew from the young green fruits and use them as salad. The most common mode of utilization is using the leaf for preparation of Moringa tea. The Moringa tree does not need intensive management, establish easily, adapt well to the arid climate of Botswana and grow with minimal care. Most of the interviewed households indicated that there is no challenge associated with growing the trees. Despite the general difficulty of cultivating crops in the country due to the harsh hot climate and shortage of water, the species needs little attention to grow, and there is no particular problem associated with production of the trees. Majority of the respondents indicated that there is a big potential to expand and commercialize Moringa in Botswana if people are made aware of its benefits. The study revealed that M. oleifera is grown in Gaborone though it is generally underutilized despite its huge potential. There is a huge knowledge gap about the nutritional uses of Moringa. Given the potential food and non-food applications of Moringa, there is an urgent need to promote its cultivation and utilization so that it can contribute its share in Government efforts to ensure food security in Botswana.
Land use/land cover (LULC) dynamics and the resulting changes in ecosystems, as well as the services they provide, are a consequence of human activities and environmental drivers, such as invasive ...alien plant species. This study assessed the changes in LULC and ecosystem service values (ESVs) in the Afar National Regional State, Ethiopia, which experiences a rapid invasion by the alien tree Prosopis juliflora (Swartz DC). Landsat satellite data of 1986, 2000 and 2017 were used in Random Forest algorithm to assess LULC changes in the last 31 years, to calculate net changes for different LULC types and the associated changes in ESVs. Kappa accuracies of 88% and higher were obtained for the three LULC classifications. Post-classification change analyses for the period between 1986 and 2017 revealed a positive net change for Prosopis invaded areas, cropland, salt flats, settlements and waterbodies. The rate of Prosopis invasion was estimated at 31,127 ha per year. Negative net changes were found for grassland, bareland, bush-shrub-woodland, and natural forests. According to the local community representatives, the four most important drivers of LULC dynamics were climate change, frequent droughts, invasive species and weak traditional law. Based on two different ESVs estimations, the ecosystem changes caused by LULC changes resulted in an average loss of ESVs in the study area of about US$ 602 million (range US$ 112 to 1091 million) over the last 31 years. With an increase in area by 965,000 ha, Prosopis-invaded land was the highest net change during the study period, followed by grassland (−599,000 ha), bareland (−329,000 ha) and bush-shrub-woodland (−327,000 ha). Our study provides evidence that LULC changes in the Afar Region have led to a significant loss in ESVs, with serious consequences for the livelihoods of the rural people.
Display omitted
•LULC transformation analysis (1986-2017) showed reduction in grassland and bush-shrub-land to Prosopis.•Prosopis invasion increased at annual rates of 31,127 ha while grassland and bush-shrub-woodland declined at 19,312 ha and 10,543 ha, respectively.•Local communities perceive that climate change, frequent droughts and invasive species as the major drivers of LULC changes.•Losses in annual ESVs are estimated at US$ 602 million (range 112 to 1,092 million).
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