خيارات البحث
النتائج 1 - 10 من 104
Temporal and spatial changes in land use patterns and biodiversity in relation to farm productivity at multiple scales in Tigray, Ethiopia
2008
Hadgu Meles, K.
Loss of biodiversity, including agro-biodiversity affects smallholders in dry-land regions by decreasing the buffering capacity of the agro-ecosystem and increasing proneness to yield variability including crop failure due to weather extremes. Loss of biodiversity is associated with land use/land cover (LULC) changes that are related to a range of biophysical and socio-economic drivers. This thesis is focused on the Tigray region in northern Ethiopia which has experienced severe loss of biodiversity over the last decades at the regional scale, while loss of genetic variation of crops at the farm and field scale are ongoing as a result of agricultural technology adoption processes. The overall goal of this thesis research was to identify and analyse factors affecting loss of agro-biodiversity in Tigray, Ethiopia, and relate agro-biodiversity loss to LULC changes, soil erosion, farming practices and agricultural productivity. A multi-scale approach was adopted. At the regional scale, LULC changes over the last decades were investigated using a time-series of remotely sensed data to assess changes in biodiversity. At the farm scale, changes in farming practices and land use between 2000 and 2005 were described along with their effects on agro-biodiversity. These changes were related to biophysical and socio-economic drivers. Finally, at the field scale, the consequences of the presence of Acacia albida trees for productivity were assessed. A survey among 151 farms in Tigray indicated that higher numbers of species of trees and shrubs, along with cultivation of land races was associated with traditional farming practices of smallholders in 2000 and 2005. Classified maps from remotely sensed data indicated that significant changes in LULC were accompanied by loss of biodiversity and intensification of agricultural production. At the same time, overall caloric yields were highest and soil erosion lowest in sparsely cultivated areas with high biodiversity, where traditional farming practices still dominate. At the farm scale, it was shown that A. albida trees contribute significantly to soil fertility and barley yield. Results of this project may assist policy development on agro-biodiversity restoration by providing information on long-term historical trends, insight into their drivers, and consequences for food security among resource poor smallholders in the region.
اظهر المزيد [+] اقل [-]Land-use changes in Mount Papandayan: its associated impacts on biodiversity and carbon stock النص الكامل
2008
E. Sulistyawati | Y. I. Ulumuddin | M. Zuhri
Given the fact that most lowland forests in the highly populated island of Java have been converted to other uses, the mountain forests play a critical role in providing key ecosystem services such as biodiversity maintenance and partial stabilization of climate through carbon sequestration. This paper assesses the extent to which land-use changes in Mount Papandayan happening during 1994 -2001 has resulted in loss of forest habitats and carbon sequestered in vegetation. The assessment was done by analyzing the data derived from biodiversity survey for plants and birds, field-measurement of carbon stocks, remote sensing, and interview. The remote sensing method (using Landsat) was used to quantify the extent of deforestation. In order to estimate carbon stock and its changes in the landscape, we have developed a statistical model based on the correlation between the spectral characteristics and field-measurement of carbon stocks. The results indicated that the mixed-forest of Mount Papandayan had high diversity of plants and birds. Deforestation mainly due to conversion to agricultural fields has been instrumental in causing the loss of such diverse habitat. During 1994-2001, around 2,700 hectares of forest have disappeared with the associated loss of carbon of more than 800,000 tons. This paper will also highlight the implication of this finding to the ecosystem management in order to conserve the remaining and restoring the forest.
اظهر المزيد [+] اقل [-]Temporal and spatial changes in land use patterns and biodiversity in relation to farm productivity at multiple scales in Tigray, Ethiopia النص الكامل
2008
Hadgu Meles, K.
Loss of biodiversity, including agro-biodiversity affects smallholders in dry-land regions by decreasing the buffering capacity of the agro-ecosystem and increasing proneness to yield variability including crop failure due to weather extremes. Loss of biodiversity is associated with land use/land cover (LULC) changes that are related to a range of biophysical and socio-economic drivers. This thesis is focused on the Tigray region in northern Ethiopia which has experienced severe loss of biodiversity over the last decades at the regional scale, while loss of genetic variation of crops at the farm and field scale are ongoing as a result of agricultural technology adoption processes. The overall goal of this thesis research was to identify and analyse factors affecting loss of agro-biodiversity in Tigray, Ethiopia, and relate agro-biodiversity loss to LULC changes, soil erosion, farming practices and agricultural productivity. A multi-scale approach was adopted. At the regional scale, LULC changes over the last decades were investigated using a time-series of remotely sensed data to assess changes in biodiversity. At the farm scale, changes in farming practices and land use between 2000 and 2005 were described along with their effects on agro-biodiversity. These changes were related to biophysical and socio-economic drivers. Finally, at the field scale, the consequences of the presence of Acacia albida trees for productivity were assessed. A survey among 151 farms in Tigray indicated that higher numbers of species of trees and shrubs, along with cultivation of land races was associated with traditional farming practices of smallholders in 2000 and 2005. Classified maps from remotely sensed data indicated that significant changes in LULC were accompanied by loss of biodiversity and intensification of agricultural production. At the same time, overall caloric yields were highest and soil erosion lowest in sparsely cultivated areas with high biodiversity, where traditional farming practices still dominate. At the farm scale, it was shown that A. albida trees contribute significantly to soil fertility and barley yield. Results of this project may assist policy development on agro-biodiversity restoration by providing information on long-term historical trends, insight into their drivers, and consequences for food security among resource poor smallholders in the region.
اظهر المزيد [+] اقل [-]Nilai Penting Agroforestri, Hutan Rakyat dan Lahan Pertanian dalam Konservasi Keanekaragaman Jenis Burung di Paliyan, Gunung Kidul, Yogyakarta النص الكامل
2008
Satyawan Pudyatmoko
Important Values of Agroforestry, Community Forest, and Agricultural Land on Conservation of Bird Diversity in Paliyan, Gunungkidul, Yogyakarta Agroforestry is recognized as a land use management that capable to integrate the need of local peoples and the concern of biodiversity conservation. However, some contradictory results of studies made the importance of agroforestry on conservation of biodiversity questionable. To understand the role of agroforestry in biodiversity conservation, bird community assemblages of three land use types namely private forests, agroforestry and annual crops were compared. Single belt point count with a radius of 50 m was used to survey birds. In general species diversity in the study area was at a moderate level. Statistically, bird communities between sites did not differ significantly in term of their abundance, species composition, and diversity. It was because patch context plays more important role than patch content. However, it was found that in all community parameter agroforestry area has higher values than those of crops. Consistent with the previous studies, insectivorous birds were the most sensitive to land use changes. The conservation value of Paliyan area was relatively low, because most of species were abundant, and no species inhabit endangered status according to IUCN criteria. Implication of this research was that Paliyan area need a large-compact habitat to conserve high bird diversity.
اظهر المزيد [+] اقل [-]Biodiversity patterns and the importance of landscape-levelland-use intensity and fragmentation of forest habitats in Europe النص الكامل
2008
Edman, Tobias
Changes have been taking place in the landscapes of Europe for thousands of years. The aim of the studies presented in this thesis was to contribute to the understanding of the relation between human landscape changes and some aspects of forest-related biodiversity. A wide variety of spatially explicit data was used for the analysis and assessment of biodiversity, land cover and land use, together with climatic variables and topography. Differences in national economic conditions were found to affect landscapes with a common ancestry in the Carpathian Mountains, resulting in different trajectories of landscape development. These results highlight the importance of human land use on landscape composition. The method of comparing landscapes with different histories can be used to develop benchmarks for landscape change studies and policy evaluation. Clear relationships were found between land use parameters and functional diversity, species richness and species richness within functional groups. The usefulness of a meta-population model was evaluated by comparison with an area-based model for predicting the occurrence of the White-backed Woodpecker (Dendrocopos leucotos) in Poland. The meta-population model predicted the occurrence of the species better than the area-based model. The area-based model overestimated the occurrence of White-backed Woodpeckers, especially in areas with fragmented forests. The main conclusions of this study are that economic incentives shape landscapes; biodiversity patterns in Europe reflect the history of human landscape changes; and that land use intensity and spatial configuration, and the connectivity of suitable habitats are of importance for the predictive ability of landscape suitability models.
اظهر المزيد [+] اقل [-]Indicators for biodiversity in agricultural landscapes: a pan-European study النص الكامل
2008
Billeter, R. | Liira, J. | Bailey, D. | Bugter, R.J.F. | Arens, P.F.P. | Augenstein, I. | Aviron, S. | Baudry, J. | Bukacek, R. | Burel, F. | Cerny, M. | de Blust, G. | de Cock, R. | Diekotter, T. | Dietz, H. | Dirksen, J. | Dormann, C. | Durka, W. | Frenzel, M. | Hamersky, R. | Hendrickx, F. | Herzog, F. | Klotz, S. | Koolstra, B.J.H. | Lausch, A. | Le Coeur, D. | Maelfait, J.P. | Opdam, P. | Roubalova, M. | Schermann, A. | Schermann, N. | Schmidt, T. | Schweiger, O. | Smulders, M.J.M. | Speelmans, M. | Simova, P. | Verboom, J. | van Wingerden, W.K.R.E. | Zobel, M. | Edwards, P.J.
1. In many European agricultural landscapes, species richness is declining considerably. Studies performed at a very large spatial scale are helpful in understanding the reasons for this decline and as a basis for guiding policy. In a unique, large-scale study of 25 agricultural landscapes in seven European countries, we investigated relationships between species richness in several taxa, and the links between biodiversity and landscape structure and management. 2. We estimated the total species richness of vascular plants, birds and five arthropod groups in each 16-km2 landscape, and recorded various measures of both landscape structure and intensity of agricultural land use. We studied correlations between taxonomic groups and the effects of landscape and land-use parameters on the number of species in different taxonomic groups. Our statistical approach also accounted for regional variation in species richness unrelated to landscape or land-use factors. 3. The results reveal strong geographical trends in species richness in all taxonomic groups. No single species group emerged as a good predictor of all other species groups. Species richness of all groups increased with the area of semi-natural habitats in the landscape. Species richness of birds and vascular plants was negatively associated with fertilizer use. 4. Synthesis and applications. We conclude that indicator taxa are unlikely to provide an effective means of predicting biodiversity at a large spatial scale, especially where there is large biogeographical variation in species richness. However, a small list of landscape and land-use parameters can be used in agricultural landscapes to infer large-scale patterns of species richness. Our results suggest that to halt the loss of biodiversity in these landscapes, it is important to preserve and, if possible, increase the area of semi-natural habitat.
اظهر المزيد [+] اقل [-]Long-term field experiments - museum relics or scientific challenge? النص الكامل
2008
Merbach, W.,Martin Luther Univ., Halle-Wittenberg (Germany). Inst. of Agricultural and Nutritional Sciences | Deubel, A.,Martin Luther Univ., Halle-Wittenberg (Germany). Inst. of Agricultural and Nutritional Sciences
Long-term field experiments - museum relics or scientific challenge? النص الكامل
2008
Merbach, W.,Martin Luther Univ., Halle-Wittenberg (Germany). Inst. of Agricultural and Nutritional Sciences | Deubel, A.,Martin Luther Univ., Halle-Wittenberg (Germany). Inst. of Agricultural and Nutritional Sciences
By reference to the Eternal Rye trial in Halle, Germany, as an example, it is demonstrated that long-term trials provide indispensable information for contemporary and future land use research. These trials serve as tools for the examination of cultivation measures or the effects of climate on nutrient dynamics and mobilization, microbial biodiversity, mineral composition or soil formation processes. They are therefore essential for the evaluation of land-use strategies or climatic change and, because of that, can provide more accuracy in related political considerations.
اظهر المزيد [+] اقل [-]Long-term field experiments - museum relics or scientific challenge? النص الكامل
2008
W. Merbach | A. Deubel
By reference to the Eternal Rye trial in Halle, Germany, as an example, it is demonstrated that long-term trials provide indispensable information for contemporary and future land use research. These trials serve as tools for the examination of cultivation measures or the effects of climate on nutrient dynamics and mobilization, microbial biodiversity, mineral composition or soil formation processes. They are therefore essential for the evaluation of land-use strategies or climatic change and, because of that, can provide more accuracy in related political considerations.
اظهر المزيد [+] اقل [-]Ecosystem Services in Productive Landscapes: New Zealand’s emerging agricultural pattern and land-use change النص الكامل
2008
Anderson, M | Barnes, AM | Wratten, SD
It is considered that New Zealand has the greatest rate of land-use change in the Western world (Penman 2008 pers. comm.). Although New Zealand’s land-use changes may be dynamic, reflecting overseas market needs in a business-agile way, the increase in agricultural intensification and in the diversity of crops grown over the last four decades is compounding the strain on the provision of ecosystem (nature’s) services (Costanza 1997, Daily et al 1997) that are necessary for long-term sustainable and profitable production. Higher animal stocking rates and yields, conversion to more intensive forms of agriculture, conversion to forestry and deer farming, increased mechanisation and increased use of fertilizers, pesticides and feedstock inputs are all indications of this steady trend (MacLeod et al 2006). In particular, the last decade has seen a rise in conversion from sheep and beef to dairy farming, a much more intensive activity. The dairy industry is currently striving to increase productivity by 4% per annum, to achieve a 50% increase in production by 2015 (MacLeod et al 2006). This policy depends increasingly on subsidies; more fertilizer, water, supplemental feeding – which may not be sourced from within the farm, or even from within New Zealand. This current trend for intensification may not be ecologically viable for the long term. Increased carbon dioxide emissions from higher fossil fuel use in mechanised intensive farming practices cannot be easily offset (Rhodes et al 2007). Conversion of rough grassland to ‘improved pasture’ has seen losses in biodiversity. Biodiversity is very valuable to agriculture, although the exact figure is difficult to ascertain (Costanza et al 1997, Sandhu et al 2007, Tilman et al 1996). New Zealand agriculture is diversifying as well as changing, examples being an increase in land use for vines and other specialty crops. Seed crops such as radish, have seen areas such as the Canterbury plains change markedly (MacLeod et al 2006). Forest plantations have seen a 110% increase in land area since 1980 (Brockerhoff et al 2008). This increase in forestry (mainly Pinus radiata) may have some biodiversity benefits.
اظهر المزيد [+] اقل [-]Potentialities for payment mechanisms for environmental services in the Congo Basin forests : The case of biodiversity conservation النص الكامل
2008
Tchiofo Lontsi, Rodine
The present study investigates the potential for direct payment for biodiversity conservation implementation in the Congo Basin. A survey realized in 31 protected areas in the Congo Basin showed that some initiatives, starting with raising awareness, are used to raise local participation in conservation, but there are very few conservation agreements with local people. Attempt to biodiversity conservation in/around PAs is done through three main approaches. Indirect incentive approaches are the most used (63%) in front of direct incentives for sustainable biodiversity use (30%). Direct incentives for biodiversity conservation (7%) are quite new and are still not bound by conservation contracts. Five initiatives are being implemented including rewards for denunciating poachers (in 2 PAs), conservation of marine turtles in Campo Ma¿an TUO, compensation of farmers for damages caused by wildlife in their farmland and paying a local community to set aside an area as no man¿s land for carbon sequestration evaluation. Three other initiatives are still in their planning phase. They are conservation concession projects proposed by conservation organizations (WWF, CI and BCI) to governments of Cameroon, CAR and DRC. Use-restriction on some elements of the biodiversity like wildlife is likely to be the best PES scheme in the Congo Basin compared to area-based schemes, since people heavily depend on land for their livelihood. The success of the conservation contracts will depend on securing property rights, a careful evaluation of opportunity costs considering ways and customs of local people, a clear definition of indicators (people efforts and results), a democratic and equitable use of compensation funds and an establishment of a strong institutional framework and monitoring authority for contract enforcement. All this may involve high transaction costs to improve efficiency of payments. Conservation contracts in the Congo Basin may not be such a cheap way to achieve biodiversity conservation as thought by many conservationists. A part from biodiversity market, possible mechanisms to finance them can be Trust fund for PA management and the future REDD mechanism. Finally, government efforts in clarification of customary rights will be required. However, the efficiency of conservation contracts to achieve biodiversity conservation is widely recognized and there is a great interest of conservationists for direct payments for biodiversity conservation in the Congo Basin. (Résumé d'auteur)
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