The objective of this study was to explore vegetation adaptability in a changing afro-alpine moorland terrestrial ecosystem on Mt. Rwenzori and to determine whether there were any links with response of vegetation to ...The objective of this study was to explore vegetation adaptability in a changing afro-alpine moorland terrestrial ecosystem on Mt. Rwenzori and to determine whether there were any links with response of vegetation to glacier recession. We analyzed the composition and distribution of plant species in relation to soils, geomorphic processes, and landscape positions in the Alpine zone. To accomplish this objective, archival data sources and published reports for this ecosystem were reviewed. A field trip was conducted in 2010 to study in detail seven vegetation sampling plots that were systematically selected using GIS maps and a nested-quadrat sampling design framework along an altitudinal gradient in the lower and upper alpine zones. Using these sampling plots, 105 vegetation and 13 soil samples were assessed in the alpine zone. Soil samples were taken for laboratory testing and analysis. The results show statistically significant differences in pH, OM, N, P, Ca, Mg, and K pools between soils samples drawn from the lower and upper alpine sites （p 〈 0.0033）. Furthermore, we observed a significant vegetation formation with numerous structural forms, but there was a limited diversity of speeies. The most significant forms included Alchemilla carpets, Bogs, Dendrosenecio woodland, and Scree slopes. The lower alpine area （3500-3900 masl） had a more diverse plant species than other areas, especially Alchemilla argyrophylla and Dendrosenecio adnivalis species that were evident due to well-drained deeper soils. The Alchemilla subnivalis were evident at a higher altitude of above 4000 mask Shifts in the Astareeeae （e.g. Senecio species） were particularly prominent even on recently deglaciated areas. The spatial variations of species distribution, structure, and composition suggest there are serious implications in terms of ecosystem adaptability, resilience, and stability that require further evaluation.展开更多
Introduction:Ecosystem change and respective conservation needs were at top priority areas in the globe especially at biodiversity hotspot zones and places of endemism like Bale eco-region.In this aspect,this study ha...Introduction:Ecosystem change and respective conservation needs were at top priority areas in the globe especially at biodiversity hotspot zones and places of endemism like Bale eco-region.In this aspect,this study had tried to assess historical landscape changes of afro-alpine forest ecosystem with its respective driving forces and effectiveness of different institutional arrangements to protect this ecosystem.Methods:The study utilized satellite imagery from Landsat series starting from 1986 to 2016,ground truth data from GPS-based field survey,focus group discussions,and reconnaissance field survey.Historical landscape maps were prepared with a mix of supervised and unsupervised image classification methods.Future landscape change simulation was undertaken by using cellular automata modeling on Dynamic Environment for Geoprocessing Objects(Dinamica EGO)software.Beyond areal change and transition of landscape elements,level of ecosystem fragmentation was assessed with FRAGSTAT software.Results:Results have shown that there is encroachment of human-induced land use patterns especially agriculture and grazing while closed canopy forest and woodland ecosystems have decreased in their extent.Simulation outputs for the coming three decades have also shown similar patterns with historical trends.Beyond changes in areal extent,landscape matrix analysis results indicated that there is increasing class and landscape level fragmentation both in its historical and future probable likelihoods.Effectiveness of different management strategies at different institutional arrangement were differ in their effectiveness that federal and regional government were not able to curve landscape change.Conclusions:In conclusion,increasing population pressure and weak policy implementation and legal enforcement has caused threats for alpine forest ecosystem in Bale eco-region.Except participatory forest management,management strategies at different institutional arrangements were failed to conserve forest.These calls reinnovated participatory forest management strategies that base community participation while simultaneously keeps livelihoods demands of local community.展开更多
East Africa is a biodiversity hotspot. Haplocarpha rueppelii （Sch.Bip.） Beauverd is mainly distributed in the alpine grassland of East Africa. Here we sampled 65 individuals of eight populations/locations of H. ruep...East Africa is a biodiversity hotspot. Haplocarpha rueppelii （Sch.Bip.） Beauverd is mainly distributed in the alpine grassland of East Africa. Here we sampled 65 individuals of eight populations/locations of H. rueppelii including hairy and glabrous forms from Mts. Elgon, Aberdare, Kenya, Kilimanjaro and Bale Mountains. We then sequenced one nuclear and three chloroplast DNA fragments and conducted phylogeographic analyses to test the taxonomic rank of the two forms and causes for the differentiation （intrinsic reproductive isolation and geographic barrier）. The results demonstrate that the species consists of two major groups, one includes the populations from Mts. Elgon, Aberdare and Bale, while the other includes Mts. Kenya and Kilimanjaro. The species has established in Mts. Kenya and Aberdare during the Pleistocene. However, migration rate for individuals between the two mountains was low as showed by gene flow analysis. A barrier for plant dispersal and gene flow would have existed between Mts. Aberdare and Kenya since at least Pleistocene. No change of the taxonomic concept of this species is needed. This study reveals a potential geographic barrier in East Africa. We hope it will arouse more scientists＇ interests in phylogeography and biodiversity of East Africa.展开更多
基金financial support from START International for funding the project activities(Makerere University and University of Tennessee at Memphis) provided us with the necessary support
文摘The objective of this study was to explore vegetation adaptability in a changing afro-alpine moorland terrestrial ecosystem on Mt. Rwenzori and to determine whether there were any links with response of vegetation to glacier recession. We analyzed the composition and distribution of plant species in relation to soils, geomorphic processes, and landscape positions in the Alpine zone. To accomplish this objective, archival data sources and published reports for this ecosystem were reviewed. A field trip was conducted in 2010 to study in detail seven vegetation sampling plots that were systematically selected using GIS maps and a nested-quadrat sampling design framework along an altitudinal gradient in the lower and upper alpine zones. Using these sampling plots, 105 vegetation and 13 soil samples were assessed in the alpine zone. Soil samples were taken for laboratory testing and analysis. The results show statistically significant differences in pH, OM, N, P, Ca, Mg, and K pools between soils samples drawn from the lower and upper alpine sites （p 〈 0.0033）. Furthermore, we observed a significant vegetation formation with numerous structural forms, but there was a limited diversity of speeies. The most significant forms included Alchemilla carpets, Bogs, Dendrosenecio woodland, and Scree slopes. The lower alpine area （3500-3900 masl） had a more diverse plant species than other areas, especially Alchemilla argyrophylla and Dendrosenecio adnivalis species that were evident due to well-drained deeper soils. The Alchemilla subnivalis were evident at a higher altitude of above 4000 mask Shifts in the Astareeeae （e.g. Senecio species） were particularly prominent even on recently deglaciated areas. The spatial variations of species distribution, structure, and composition suggest there are serious implications in terms of ecosystem adaptability, resilience, and stability that require further evaluation.
文摘Introduction:Ecosystem change and respective conservation needs were at top priority areas in the globe especially at biodiversity hotspot zones and places of endemism like Bale eco-region.In this aspect,this study had tried to assess historical landscape changes of afro-alpine forest ecosystem with its respective driving forces and effectiveness of different institutional arrangements to protect this ecosystem.Methods:The study utilized satellite imagery from Landsat series starting from 1986 to 2016,ground truth data from GPS-based field survey,focus group discussions,and reconnaissance field survey.Historical landscape maps were prepared with a mix of supervised and unsupervised image classification methods.Future landscape change simulation was undertaken by using cellular automata modeling on Dynamic Environment for Geoprocessing Objects(Dinamica EGO)software.Beyond areal change and transition of landscape elements,level of ecosystem fragmentation was assessed with FRAGSTAT software.Results:Results have shown that there is encroachment of human-induced land use patterns especially agriculture and grazing while closed canopy forest and woodland ecosystems have decreased in their extent.Simulation outputs for the coming three decades have also shown similar patterns with historical trends.Beyond changes in areal extent,landscape matrix analysis results indicated that there is increasing class and landscape level fragmentation both in its historical and future probable likelihoods.Effectiveness of different management strategies at different institutional arrangement were differ in their effectiveness that federal and regional government were not able to curve landscape change.Conclusions:In conclusion,increasing population pressure and weak policy implementation and legal enforcement has caused threats for alpine forest ecosystem in Bale eco-region.Except participatory forest management,management strategies at different institutional arrangements were failed to conserve forest.These calls reinnovated participatory forest management strategies that base community participation while simultaneously keeps livelihoods demands of local community.
基金supported by Sino-Africa Joint Research Center(Y323771W07,SAJC201322)the National Natural Science Foundation of China(31300182)
文摘East Africa is a biodiversity hotspot. Haplocarpha rueppelii （Sch.Bip.） Beauverd is mainly distributed in the alpine grassland of East Africa. Here we sampled 65 individuals of eight populations/locations of H. rueppelii including hairy and glabrous forms from Mts. Elgon, Aberdare, Kenya, Kilimanjaro and Bale Mountains. We then sequenced one nuclear and three chloroplast DNA fragments and conducted phylogeographic analyses to test the taxonomic rank of the two forms and causes for the differentiation （intrinsic reproductive isolation and geographic barrier）. The results demonstrate that the species consists of two major groups, one includes the populations from Mts. Elgon, Aberdare and Bale, while the other includes Mts. Kenya and Kilimanjaro. The species has established in Mts. Kenya and Aberdare during the Pleistocene. However, migration rate for individuals between the two mountains was low as showed by gene flow analysis. A barrier for plant dispersal and gene flow would have existed between Mts. Aberdare and Kenya since at least Pleistocene. No change of the taxonomic concept of this species is needed. This study reveals a potential geographic barrier in East Africa. We hope it will arouse more scientists＇ interests in phylogeography and biodiversity of East Africa.
