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Paulo Van Breugel - One of the best experts on this subject based on the ideXlab platform.
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the gerire hills a se ethiopian outpost of the transitional semi evergreen Bushland vegetation endemism and three new species croton elkerensis euphorbiaceae gnidia elkerensis thymelaeaceae and plectranthus spananthus lamiaceae
Webbia, 2018Co-Authors: Ib Friis, Paulo Van Breugel, Michael G Gilbert, Alan Paton, Odile Weber, Sebsebe DemissewAbstract:ABSTRACTThe vegetation of the plateaux of the Gerire Hills, of unique geology, represents an outlier of the Transitional semi-evergreen Bushland of the eastern escarpment of the Ethiopian highlands...
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the transitional semi evergreen Bushland in ethiopia characterization and mapping of its distribution using predictive modelling
Applied Vegetation Science, 2016Co-Authors: Paulo Van Breugel, Ib Friis, Sebsebe DemissewAbstract:Question Evergreen Bushlands in Ethiopia have been inadequately studied and mapped. We address the question whether there is a transitional semi-evergreen Bushland on the eastern escarpment of the Ethiopian Highlands, with unique floristic characteristics that distinguish it from the evergreen Bushlands in other parts of Ethiopia and eastern Africa. Methods Based on a review of the recent descriptions of evergreen Bushlands in Ethiopia, we hypothesize that there is a distinct zone of natural semi-evergreen Bushland, which is restricted to the eastern and southeastern escarpment of the Ethiopian Highlands. In contrast, evergreen Bushlands in other parts of Ethiopia are considered to be of a secondary nature. To test this hypothesis, we carried out qualitative vegetation surveys in 354 locations across Ethiopia and classified the vegetation in these locations based on the occurrences of indicator species. Based on this data, we created predictive distribution models of the semi-evergreen Bushland in Ethiopia using various environmental distribution models. We furthermore compared the occurrences of characteristic evergreen Bushland species in Ethiopia with the occurrence of these species within the evergreen Bushlands in Kenya and Uganda. Results The vegetation surveys confirmed the existence of a distinct type of evergreen Bushland vegetation. The transitional semi-evergreen Bushland forms a transitional zone between the Acacia–Commiphora woodland and Bushland and the Afromontane forest on the eastern and southeastern escarpments of Ethiopia, but is also characterized by a number of species that, within Ethiopia, are unique to this zone. Most of the characteristic species of the transitional semi-evergreen Bushland are not found or only in lower densities in western Ethiopia. There is, furthermore, a limited overlap in characteristic species of the evergreen Bushlands of Kenya and Uganda. Conclusions Our results provide important information on the hitherto inadequately studied semi-evergreen Bushland of Ethiopia. It highlights the unique character of this part of the evergreen Bushlands in Ethiopia, which we argue should be taken into account for future conservation planning.
Sebsebe Demissew - One of the best experts on this subject based on the ideXlab platform.
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the gerire hills a se ethiopian outpost of the transitional semi evergreen Bushland vegetation endemism and three new species croton elkerensis euphorbiaceae gnidia elkerensis thymelaeaceae and plectranthus spananthus lamiaceae
Webbia, 2018Co-Authors: Ib Friis, Paulo Van Breugel, Michael G Gilbert, Alan Paton, Odile Weber, Sebsebe DemissewAbstract:ABSTRACTThe vegetation of the plateaux of the Gerire Hills, of unique geology, represents an outlier of the Transitional semi-evergreen Bushland of the eastern escarpment of the Ethiopian highlands...
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the transitional semi evergreen Bushland in ethiopia characterization and mapping of its distribution using predictive modelling
Applied Vegetation Science, 2016Co-Authors: Paulo Van Breugel, Ib Friis, Sebsebe DemissewAbstract:Question Evergreen Bushlands in Ethiopia have been inadequately studied and mapped. We address the question whether there is a transitional semi-evergreen Bushland on the eastern escarpment of the Ethiopian Highlands, with unique floristic characteristics that distinguish it from the evergreen Bushlands in other parts of Ethiopia and eastern Africa. Methods Based on a review of the recent descriptions of evergreen Bushlands in Ethiopia, we hypothesize that there is a distinct zone of natural semi-evergreen Bushland, which is restricted to the eastern and southeastern escarpment of the Ethiopian Highlands. In contrast, evergreen Bushlands in other parts of Ethiopia are considered to be of a secondary nature. To test this hypothesis, we carried out qualitative vegetation surveys in 354 locations across Ethiopia and classified the vegetation in these locations based on the occurrences of indicator species. Based on this data, we created predictive distribution models of the semi-evergreen Bushland in Ethiopia using various environmental distribution models. We furthermore compared the occurrences of characteristic evergreen Bushland species in Ethiopia with the occurrence of these species within the evergreen Bushlands in Kenya and Uganda. Results The vegetation surveys confirmed the existence of a distinct type of evergreen Bushland vegetation. The transitional semi-evergreen Bushland forms a transitional zone between the Acacia–Commiphora woodland and Bushland and the Afromontane forest on the eastern and southeastern escarpments of Ethiopia, but is also characterized by a number of species that, within Ethiopia, are unique to this zone. Most of the characteristic species of the transitional semi-evergreen Bushland are not found or only in lower densities in western Ethiopia. There is, furthermore, a limited overlap in characteristic species of the evergreen Bushlands of Kenya and Uganda. Conclusions Our results provide important information on the hitherto inadequately studied semi-evergreen Bushland of Ethiopia. It highlights the unique character of this part of the evergreen Bushlands in Ethiopia, which we argue should be taken into account for future conservation planning.
Pellikka Petri - One of the best experts on this subject based on the ideXlab platform.
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Soil greenhouse gas emissions from a sisal chronosequence in Kenya
'Elsevier BV', 2021Co-Authors: Wachiye, Sheila Aswani, Heiskanen Janne, Merbold Lutz, Vesala Timo, Rinne Janne, Leitner Sonja, Räsänen Matti, Vuorinne Ilja, Pellikka PetriAbstract:Sisal (Agave sisalana) is a climate-resilient crop grown on large-scale farms in semi-arid areas. However, no studies have investigated soil greenhouse gas (GHGs: CO2, N2O and CH4) fluxes from these plantations and how they relate to other land cover types. We examined GHG fluxes (Fs) in a sisal chronosequence at Teita Sisal Estate in southern Kenya. The effects of stand age on Fs were examined using static GHG chambers and gas chromatography for a period of one year in seven stands: young stands aged 1-3 years, mature stands aged 7-8 years, and old stands aged 13-14 years. Adjacent Bushland served as a control site representing the surrounding land use type. Mean CO2 fluxes were highest in the oldest stand (56 +/- 3 mg C m(-2) h(-1)) and lowest in the 8-year old stand (38 +/- 3 mg C m(-2) h(-1)), which we attribute to difference in root respiration between the stand. All stands had 13-28% higher CO2 fluxes than Bushland (32 +/- 3 mg C m(-2) h(-1)). CO2 fluxes in the wet season were about 70% higher than dry season across all sites. They were influenced by soil water content (W-S) and vegetation phenology. Mean N2O fluxes were very low (Peer reviewe
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Aboveground Biomass Distribution in a Multi-Use Savannah Landscape in Southeastern Kenya: Impact of Land Use and Fences
Multidisciplinary Digital Publishing Institute, 2020Co-Authors: Amara Edward, Adhikari Hari, Munyao Martha, Omondi Patrick, Heiskane Janne, Siljande Mika, Pellikka PetriAbstract:Savannahs provide valuable ecosystem services and contribute to continental and global carbon budgets. In addition, savannahs exhibit multiple land uses, e.g., wildlife conservation, pastoralism, and crop farming. Despite their importance, the effect of land use on woody aboveground biomass (AGB) in savannahs is understudied. Furthermore, fences used to reduce human–wildlife conflicts may affect AGB patterns. We assessed AGB densities and patterns, and the effect of land use and fences on AGB in a multi-use savannah landscape in southeastern Kenya. AGB was assessed with field survey and airborne laser scanning (ALS) data, and a land cover map was developed using Sentinel-2 satellite images in Google Earth Engine. The highest woody AGB was found in riverine forest in a conservation area and in Bushland outside the conservation area. The highest mean AGB density occurred in the non-conservation area with mixed Bushland and cropland (8.9 Mg·ha−1), while the lowest AGB density (2.6 Mg·ha−1) occurred in overgrazed grassland in the conservation area. The largest differences in AGB distributions were observed in the fenced boundaries between the conservation and other land-use types. Our results provide evidence that conservation and fences can create sharp AGB transitions and lead to reduced AGB stocks, which is a vital role of savannahs as part of carbon sequestration
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Aboveground Biomass Distribution in a Multi-Use Savannah Landscape in Southeastern Kenya: Impact of Land Use and Fences
'MDPI AG', 2020Co-Authors: Amara Edward, Adhikari Hari, Munyao Martha, Omondi Patrick, Heiskane Janne, Siljande Mika, Pellikka PetriAbstract:Savannahs provide valuable ecosystem services and contribute to continental and global carbon budgets. In addition, savannahs exhibit multiple land uses, e.g., wildlife conservation, pastoralism, and crop farming. Despite their importance, the effect of land use on woody aboveground biomass (AGB) in savannahs is understudied. Furthermore, fences used to reduce human–wildlife conflicts may affect AGB patterns. We assessed AGB densities and patterns, and the effect of land use and fences on AGB in a multi-use savannah landscape in southeastern Kenya. AGB was assessed with field survey and airborne laser scanning (ALS) data, and a land cover map was developed using Sentinel-2 satellite images in Google Earth Engine. The highest woody AGB was found in riverine forest in a conservation area and in Bushland outside the conservation area. The highest mean AGB density occurred in the non-conservation area with mixed Bushland and cropland (8.9 Mg·ha−1), while the lowest AGB density (2.6 Mg·ha−1) occurred in overgrazed grassland in the conservation area. The largest differences in AGB distributions were observed in the fenced boundaries between the conservation and other land-use types. Our results provide evidence that conservation and fences can create sharp AGB transitions and lead to reduced AGB stocks, which is a vital role of savannahs as part of carbon sequestration.Peer reviewe
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Climatic impacts of Bushland to cropland conversion in Eastern Africa
'Elsevier BV', 2020Co-Authors: Abera Temesgen, Heiskanen Janne, Pellikka Petri, Adhikari Hari, Maeda EduardoAbstract:Bushlands (Acacia-Commiphora) constitute the largest and one of the most threatened ecosystems in East Africa. Although several studies have investigated the climatic impacts of land changes on local and global climate, the main focus has been on forest loss and the impacts of Bushland clearing thus remain poorly understood. Measuring the impacts of Bushland loss on local climate is challenging given that changes often occur at fragmented and small patches. Here, we apply high-resolution satellite imagery and land surface flux modeling approaches to unveil the impacts of Bushland clearing on surface biophysical properties and its associated effects on surface energy balance and land surface temperature. Our results show that Bushland clearing leads to an average reduction in evapotranspiration of 0.4 mm day(-1). The changes in surface biophysical properties affected the surface energy balance components with different magnitude. The reduction in latent heat flux was stronger than other surface energy fluxes and resulted in an average net increase in daytime land surface temperature (LST) of up to 1.75 K. These results demonstrate the important impact of Bushland-to-cropland conversion on the local climate, as they reveal increases in LST of a magnitude comparable to those caused by forest loss. This finding highlights the necessity of Bushland conservation for regulating the land surface temperature in East Africa and, at the same time, warns of the climatic impacts of clearing Bushlands for agriculture. (c) 2020 The Authors. Published by Elsevier B.V.Peer reviewe
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Aboveground Biomass Distribution in a Multi-Use Savannah Landscape in Southeastern Kenya: Impact of Land Use and Fences
'MDPI AG', 2020Co-Authors: Amara Edward, Heiskanen Janne, Adhikari Hari, Siljander Mika, Munyao Martha, Omondi Patrick, Pellikka PetriAbstract:Savannahs provide valuable ecosystem services and contribute to continental and global carbon budgets. In addition, savannahs exhibit multiple land uses, e.g., wildlife conservation, pastoralism, and crop farming. Despite their importance, the effect of land use on woody aboveground biomass (AGB) in savannahs is understudied. Furthermore, fences used to reduce human-wildlife conflicts may affect AGB patterns. We assessed AGB densities and patterns, and the effect of land use and fences on AGB in a multi-use savannah landscape in southeastern Kenya. AGB was assessed with field survey and airborne laser scanning (ALS) data, and a land cover map was developed using Sentinel-2 satellite images in Google Earth Engine. The highest woody AGB was found in riverine forest in a conservation area and in Bushland outside the conservation area. The highest mean AGB density occurred in the non-conservation area with mixed Bushland and cropland (8.9 Mg center dot ha(-1)), while the lowest AGB density (2.6 Mg center dot ha(-1)) occurred in overgrazed grassland in the conservation area. The largest differences in AGB distributions were observed in the fenced boundaries between the conservation and other land-use types. Our results provide evidence that conservation and fences can create sharp AGB transitions and lead to reduced AGB stocks, which is a vital role of savannahs as part of carbon sequestration.Peer reviewe
Stefan Rose - One of the best experts on this subject based on the ideXlab platform.
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influence of suburban edges on invasion of pittosporum undulatum into the Bushland of northern sydney australia
Austral Ecology, 1997Co-Authors: Stefan RoseAbstract:Suburban edges are shown to exert a major influence on invasion of the native Pittosporum undulatum Vent, in dry sclerophyll Bushland of northern Sydney. Transect data from fifteen urban Bushland sites spanning approximately 90 years of development indicate significant increases of P. undulatum with time. Basal area, density and frequencies of plants in all size-classes increased significantly with age of adjoining development. Mean basal area at edges of old sites was 5700 times greater than in comparable Bushland in larger reserve interiors. The effect of age was compounded by the greater impact of edge effects in narrower reserves of older suburbs. Basal areas and proportion of reproductive plants decreased significantly with distance into the reserve. Older sites contained larger but fewer individuals at the edge, compared with high densities of smaller plants further into the reserve, suggesting an advanced successional stage. The overall relationship of density with distance was not significant. The observed clumping of seedlings beneath canopies is consistent with previous work on seed dispersal by vectors, and enhanced seedling recruitment in safe sites. Pittosporum basal area and density reached no maximum levels with age, implying ongoing invasion. The study indicated some factors which appeared to promote the establishment of P. undulatum in the study area. Signs of fire were negatively correlated across all sites with basal area and density of P. undulatum. Human disturbance was positively correlated with the same variables. On the basis of findings in this study, some broad priorities for management of Pittosporum in urban Bushland are suggested.
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changes in floristic composition of urban Bushland invaded by pittosporum undulatum in northern sydney australia
Australian Journal of Botany, 1997Co-Authors: Stefan Rose, Peter G FairweatherAbstract:Differences in species composition of urban Bushland sites that had been subjected to increasing degradation and progressive invasion of Pittosporum undulatum Vent. were assessed using nonparametric multivariate and other statistical techniques. Increasing suburb age was found to significantly affect community pattern as a whole, specifically through increased proportions of exotic species, decreased native species richness and sustained shifts in the relative importance of individual species. Older suburbs were typified by species that were mesic, fire-sensitive, shade-tolerant and adapted to relatively moist, nutrient-rich edaphic conditions. These species included P. undulatum and many invasive exotics. Many native species decreased substantially in rank importance with increasing suburb age, to the point of elimination in older suburbs. These included one vulnerable taxon (Tetratheca glandulosa Sm.). Overall community pattern was correlated with abundance of P. undulatum, fire and human disturbance. Relative cover of P. undulatum was found to be significantly correlated with increased proportions of exotic species and reduced native species richness and diversity. While most exotic species were concentrated within 30 m of the suburban edge, it is suggested that most management effort should be directed at those exotic species that commonly establish throughout Bushland remnants. The study also provided an opportunity to test the application of the multivariate software package PRIMER in assessing environmental impact on vegetation communities.
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integrating management of pittosporum undulatum with other environmental weeds in sydney s urban Bushland
Pacific Conservation Biology, 1997Co-Authors: Stefan RoseAbstract:Natural Bushland is a dwindling resource in the Sydney Metropolitan Area, not only because of direct clearing, but also because uncontrolled impacts from surrounding development have caused increasing degradation over time. Community change has been characterized by invasions of environmental weeds, and consequent displacement of many indigenous species. A few locally native species, Pittosporum undulatum in particular, have emerged as environmental weeds. Invasion of new habitats within a species' natural geographic range must be recognized, since their impact on natural communities can be as serious as that of the worst exotic invaders. Factors implicated as the immediate cause of environmental weed invasions include increased human-induced dispersal by birds, anthropogenic disturbance, suppression of fire and increased moisture and nutrients. Management of plant invasions often includes mitigation to reduce impacts of the immediate causes. Strategies to maximize the success of mitigation by identifying and ameliorating the factors which impact Bushland from remote sources are discussed. Practical recommendations for restoration of degraded sites are given. Native weeds such as P. undulatum require specialized treatment within an integrated environmental weed management strategy. It is stressed that application of the best management strategies available will be wasted if more fundamental issues related to current planning practices are ignored. Uncoordinated and ad hoc decisions are continuing to reduce urban Bushland to mere remnants with high edge-to-interior ratios. Only when these practices are recognized and addressed can long-term success in the treatment of environmental weed invasions be achieved by the many excellent restoration techniques being developed.
Eduardo Eiji Maeda - One of the best experts on this subject based on the ideXlab platform.
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climatic impacts of Bushland to cropland conversion in eastern africa
Science of The Total Environment, 2020Co-Authors: Temesgen Alemayehu Abera, Janne Heiskanen, Petri Pellikka, Hari Adhikari, Eduardo Eiji MaedaAbstract:Abstract Bushlands (Acacia-Commiphora) constitute the largest and one of the most threatened ecosystems in East Africa. Although several studies have investigated the climatic impacts of land changes on local and global climate, the main focus has been on forest loss and the impacts of Bushland clearing thus remain poorly understood. Measuring the impacts of Bushland loss on local climate is challenging given that changes often occur at fragmented and small patches. Here, we apply high-resolution satellite imagery and land surface flux modeling approaches to unveil the impacts of Bushland clearing on surface biophysical properties and its associated effects on surface energy balance and land surface temperature. Our results show that Bushland clearing leads to an average reduction in evapotranspiration of 0.4 mm day−1. The changes in surface biophysical properties affected the surface energy balance components with different magnitude. The reduction in latent heat flux was stronger than other surface energy fluxes and resulted in an average net increase in daytime land surface temperature (LST) of up to 1.75 K. These results demonstrate the important impact of Bushland-to-cropland conversion on the local climate, as they reveal increases in LST of a magnitude comparable to those caused by forest loss. This finding highlights the necessity of Bushland conservation for regulating the land surface temperature in East Africa and, at the same time, warns of the climatic impacts of clearing Bushlands for agriculture.
