Suchergebnisse

Neotropical savannas are diversified systems, especially those of the Brazilian Cerrado, with a vascular flora exceeding 7,000 species, 45 % of these being endemic, which makes it the richest tropical savanna in the world. This biodiversity is threatened by the expansion of the agricultural frontiers, and the invasive African grasses. The savanna's soils are fragile, have low fertility, and high Al toxicity; nevertheless, in the savannas only the subsistence agriculture and the extensive cattle rising on low quality native grasses were practiced; but there was a quick monocropping expansion, of grains and grasses, with improved agricultural methods, government subsidies, and strong investments in fertilizers and machinery, especially in Brazil and Venezuela. Savannas became the world's most productive agricultural frontiers. These systems showed productivity loss and soil degradation, due to inadequate farming techniques, giving way to soybean-corn rotation systems with minimum tillage but a high use of herbicides. Savanna-adapted species were selected: cereals, grains, forage, and crop/livestock-integrated systems with conservationist farming were implanted. The result was a soil improvement, higher meat and milk agricultural production, and a stabilization of the agricultural expansion. There is an agreement to deepen and popularize the results of the research. Governments and NGOs are taking actions to expand the protected areas, but the world food scarcity and the run towards biofuels could generate a new agricultural expansion. ; 262-281 ; mfarinas@ula.ve

A conference presented at the IUBS UESCO/UNEP conference workshop on: Economic Driving Forces And Constraints On Savanna Land Use, Nairobi, Kenya, January 1991. ; Zimbabwe is situated on the high plateau of east and Southern Africa and lies wholly within the tropics. There are four main physiographic regions with the eastern mountains forming a narrow band along the Mozambique border. The rest of the country is characterised by the north-east to south-west watershed - the "highveld" which lies above 1200m and which descends to the Zambezi River in the north and the Limpopo River in the southeast via a scries of plateaux, with the middle veld (900-1200m) giving way to the lowveld (below 900m). The soils are mainly derived from the ancient basement complex underlying the continent and are consequently infertile. Apart from high rainfall areas of the eastern highlands the country is predominantly wooded savanna with a mean annual rainfall of between 400 an I 1200 mm per annum with some 65% of the country receiving less than 750mm per annum. The moister, north . astern sector, is able to support commercial farming based on cash and food crops and beef production. An equable tropical climate conferred by its altitude (about 66% lies above 900m) and the promise of high agricultural potential resulted in a relatively large, for an African colony, immigrant white population. This unusual situation lead to early self governing colonial status, an entrenched dual land use system (Figs. 1 and 2), a dual agricultural economy, and delayed political independence. Within this framework we examine the developing political economy of Zimbabwe and its impact on changing land use patterns and savanna ecology. This chapter identifies the principal components which have shaped contemporary savanna land use policy and practice in Zimbabwe and provides policy recommendations of national and international relevance. ; IUBS -UNESCO / UNEP

Open Access Journal; Published online: 04 Dec 2019 ; Drought, infestation of cereal crops by the parasitic weed Striga hermonthica, and poor soil fertility are the major constraints to maize production by smallholder farmers in the Sudan savannas of northern Nigeria. Four innovation platforms (IPs) were therefore established in 2008 in the Sudan savanna (SS) agroecological zone of northern Nigeria to create a stakeholder forum to address these identified food production challenges in the target areas. The IPs comprised researchers from Bayero University, Kano; Institute for Agricultural Research, Zaria; International Institute of Tropical Agriculture; state and local government extension programs in Kano and Katsina states; input and output dealers; community-based organisations; and media organisations in the two states. The current study reports on the effects of legume integration on maize performance in farmer fields and the adoption of Striga management technologies introduced in the IPs over a four-year period. The deployment of drought- Striga-tolerant and early-maturing maize varieties along with legume rotation reduced Striga infestation by 46–100% when cowpea was rotated with maize, 80–97% when groundnut was rotated with maize, and 59–94% when soybean was rotated with maize. Grain yield of maize increased by 63–88% when cowpea was rotated with maize, 69–128% when groundnut was rotated with maize, and 9–133% when soybean was rotated with maize. Participatory and detailed questionnaire-based adoption surveys showed high adoption of improved maize varieties, five years after program interventions. The maize variety 99EVDT-W-STR C0 was the most popular among all the IPs because it is early maturing, Striga-resistant, and drought-tolerant. The high maize yields and high adoption rates suggest that the IP approach was effective in disseminating maize technologies. ; Peer Review

Chapter 1. Introduction -- SECTION 1: FUNDAMENTAL PROCESSES AND INTERACTIONS IN THE SOIL-CLIMATE-VEGETATION SYSTEM -- Chapter 2. Soil Moisture Dynamics in Water-Limited Ecosystems -- Chapter3. Soil physical properties and associated soil-root interactions -- Chapter 4. Ecophysiology of plants in dry environments -- Chapter 5. Ecohydrology of Photosynthesis -- Chapter 6. Ecohydrological controls on the deposition of non-rainfall water, N and P to dryland ecosystems -- Interactions and feedbacks between climate and dryland vegetations -- SECTION 2: HYDROGEOMORPHOLOGY AND LANDFORMS OF ARID AND SEMIARID LANDSCAPES -- Chapter 8. The history and evolution of desert hydrology and landforms: The role of climate change -- Chapter 9. Ecohydrological implications of aeolian processes in drylands -- Chapter 10. Hydrological and geomorphological significance of riparian vegetation in drylands -- SECTION 3: ECOHYDROLOGIC CONTROLS on NUTRIENT CYCLING and DISTURBANCES -- Chapter 11. Ecohydrological and stoichiometric controls on soil carbon and nitrogen dynamics in drylands -- Chapter 12. Modeling of Phosphorus Dynamics in Dryland Ecosystems -- Chapter 13. Microbial nitric oxide, nitrous oxide and nitrous acid emissions from drylands -- Chapter 14. Fire regimes in dryland landscapes -- Chapter 15. Termites as mediators of the water economy of arid savanna ecosystems -- SECTION 4: ECOHYDROLOGY OF A VARIETY OF DRYLAND ECOSYSTEMS -- Chapter 16. Interactions of water and nitrogen on primary productivity across spatial and temporal scales in grassland and shrubland ecosystems -- Chapter 17. Deforestation, water availability, and nutrient cycling in dry forests -- Chapter 18. Vegetation pattern formation in drylands -- Chapter 19. Ecohydrology of agroecosystems – Interactions between local and global processes -- Chapter 20. Ecohydrology of urban ecosystems -- Chapter 21. Desertification and land degradation

Large areas in the tropics and at mid-latitudes experience pronounced seasonality and inter-annual variability in rainfall and hence water availability. Despite the importance of these seasonally dry ecosystems (SDEs) for the global carbon cycling and in providing ecosystem services, a unifying ecohydrological framework to interpret the effects of climatic variability on SDEs is still lacking. A synthesis of existing data about plant functional adaptations in SDEs, covering some 400 species, shows that leaf phenological variations, rather than physiological traits, provide the dominant control on plant-water-carbon interactions. Motivated by this result, the combined implications of leaf phenology and climatic variability on plant water use strategies are here explored with a minimalist model of the coupled soil water and plant carbon balances. The analyses are extended to five locations with different hydroclimatic forcing, spanning seasonally dry tropical climates (without temperature seasonality) and Mediterranean climates (exhibiting out of phase seasonal patterns of rainfall and temperature). The most beneficial leaf phenology in terms of carbon uptake depends on the climatic regime: evergreen species are favoured by short dry seasons or access to persistent water stores, whereas high inter-annual variability of rainy season duration favours the coexistence of multiple drought-deciduous phenological strategies. We conclude that drought-deciduousness may provide a competitive advantage in face of predicted declines in rainfall totals, while reduced seasonality and access to deep water stores may favour evergreen species. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Environmental restoration development facilities require knowledge of biodiversity (especially of vegetation. In addition, conservation remains a major challenge, hence the need to find new solutions. The current study aims at analyzing the dynamics of flora and timber trees surrounding the Waza National Park and consolidating lessons to improve conservation and sustainable management of timber resources. The methodology used is a combination of botanical and geographical approaches. Three landscape units characterize the WNP and its peripheral zone: savanna grassland, shrub savanna and wooded savanna. Flora and vegetation characteristics are different in the three landscape units. Floristic inventory identified 52 woody species. The mean absolute density of the whole zone is 81 individuals / ha. This density decreases with a decreasing gradient, from outside the park to inside. This gradient depends on the human pressure gradient which also decreases from the external to the internal park area, except when the gradient is reversed by certain factors such as cattle intrusion. The vertical structure shows that the least represented stems are stems for future planting and regeneration stems, with a very large difference from other stems. Regarding temporal dynamics, there is a regression of woody/timber vegetation cover. Each year, 478 ha of this cover disappear and 319 ha of soil degrade. To cope with the observed changes that are of anthropic, natural, bioecological or politico-institutional origin, management options have been proposed among which: zoning, implementation of a REDD + project, restoration land degraded, participatory management and eco-development. ; La connaissance de la biodiversité surtout végétale est nécessaire à la base des aménagements nécessaires à la restauration de l'environnement. La présente étude a pour objectif d'analyser la dynamique de la flore et de la végétation ligneuse à la périphérie du Parc National de Waza et en tirer des enseignements pour améliorer la conservation et la ...

Environmental restoration development facilities require knowledge of biodiversity (especially of vegetation. In addition, conservation remains a major challenge, hence the need to find new solutions. The current study aims at analyzing the dynamics of flora and timber trees surrounding the Waza National Park and consolidating lessons to improve conservation and sustainable management of timber resources. The methodology used is a combination of botanical and geographical approaches. Three landscape units characterize the WNP and its peripheral zone: savanna grassland, shrub savanna and wooded savanna. Flora and vegetation characteristics are different in the three landscape units. Floristic inventory identified 52 woody species. The mean absolute density of the whole zone is 81 individuals / ha. This density decreases with a decreasing gradient, from outside the park to inside. This gradient depends on the human pressure gradient which also decreases from the external to the internal park area, except when the gradient is reversed by certain factors such as cattle intrusion. The vertical structure shows that the least represented stems are stems for future planting and regeneration stems, with a very large difference from other stems. Regarding temporal dynamics, there is a regression of woody/timber vegetation cover. Each year, 478 ha of this cover disappear and 319 ha of soil degrade. To cope with the observed changes that are of anthropic, natural, bioecological or politico-institutional origin, management options have been proposed among which: zoning, implementation of a REDD + project, restoration land degraded, participatory management and eco-development. ; La connaissance de la biodiversité surtout végétale est nécessaire à la base des aménagements nécessaires à la restauration de l'environnement. La présente étude a pour objectif d'analyser la dynamique de la flore et de la végétation ligneuse à la périphérie du Parc National de Waza et en tirer des enseignements pour améliorer la conservation et la ...

Environmental restoration development facilities require knowledge of biodiversity (especially of vegetation. In addition, conservation remains a major challenge, hence the need to find new solutions. The current study aims at analyzing the dynamics of flora and timber trees surrounding the Waza National Park and consolidating lessons to improve conservation and sustainable management of timber resources. The methodology used is a combination of botanical and geographical approaches. Three landscape units characterize the WNP and its peripheral zone: savanna grassland, shrub savanna and wooded savanna. Flora and vegetation characteristics are different in the three landscape units. Floristic inventory identified 52 woody species. The mean absolute density of the whole zone is 81 individuals / ha. This density decreases with a decreasing gradient, from outside the park to inside. This gradient depends on the human pressure gradient which also decreases from the external to the internal park area, except when the gradient is reversed by certain factors such as cattle intrusion. The vertical structure shows that the least represented stems are stems for future planting and regeneration stems, with a very large difference from other stems. Regarding temporal dynamics, there is a regression of woody/timber vegetation cover. Each year, 478 ha of this cover disappear and 319 ha of soil degrade. To cope with the observed changes that are of anthropic, natural, bioecological or politico-institutional origin, management options have been proposed among which: zoning, implementation of a REDD + project, restoration land degraded, participatory management and eco-development. ; La connaissance de la biodiversité surtout végétale est nécessaire à la base des aménagements nécessaires à la restauration de l'environnement. La présente étude a pour objectif d'analyser la dynamique de la flore et de la végétation ligneuse à la périphérie du Parc National de Waza et en tirer des enseignements pour améliorer la conservation et la ...

The dry savannas of West Africa are undergoing rapid transformation of agricultural practices owing to the rapid human and livestock population growth, increase in agricultural intensification and accelerated climate change which has increased the incidence and severity of diseases, pests and drought. The major constraints to agricultural production in the savanna include poor soil fertility, pests and diseases of crops and livestock, parasitic weeds such as Striga hermonthica, drought, and competition between crops and livestock for resources, Inadequate policies, weak institutional mechanisms, and poor linkages among farmers, and researchers prevent adoption of improved agricultural technologies that can combat these constraints. The risk of continuous cultivation on these poor and fragile soils is huge. Integrating crop and livestock production offers ways to increase production while protecting the environment. Over the years, research and development institutions have generated several agricultural technologies to alleviate the majority of the production constraints in the West African savannas. However, most development organizations use traditional extension methods that result in poor adoption of the improved technologies. The integration of crop and livestock production is particularly desirable in intensively farmed and densely populated areas with access to urban markets. Proper integration of these practices will diversify smallholder income and increase food security. Integrated genetic and natural resource management provides the keys improved eco-efficiency. This includes integrating pesticide use with cultural practices such as modified planting date and disease control; rotating/ intercropping cereals and legumes; use of pest resistant\tolerant cultivars to increase the effectiveness of pest control and reduce the need for pesticides; and improving soil fertility restoration/maintenance. Government and national institutions in West Africa are encouraged to scale-out these technologies to wider areas for increased benefit to farmers through the use of proven extension methods. ; Peer Review

International audience ; Kinshasa, the capital of the Democratic Republic of the Congo, has some 8 million inhabitants and is mainly surrounded by savanna and patches of degraded forest. Estimated fuelwood consumption is in the range of 3 to 6 million tones of fuelwood equivalent per year (representing 0.6 to 1.2 MT of charcoal per year if all the wood were charcoaled). The Mampu project was designed as the pilot phase of a reforestation project covering 100 000 hectares of sandy soil on the Bateke plateau and aiming to remedy wood and charcoal scarcities. Despite the conflicts, about 8000 hectares of Acacia auriculiformis were planted, mainly from 1987 to 1993. From about 1994, the Mampu plantation was divided into 25 hectare plots for 320 farming families. Cultivation mainly follows the agroforestry pattern based on improved fallows, which draws on traditional slash-and-burn farming. Total charcoal production from the plantation varies from 8 000 to 12 000 tonnes per year, in addition to 10 000 T/year of cassava, 1 200 T/year of maize and 6 T/year of honey. The success of the project is an incentive to apply the model to the savanna lands on the Bateke plateaus, taking traditional land rights into consideration and continuing activities to diversify and process production locally. This will help to cover a larger share of urban needs for renewable energy while also creating rural employment. However, other agroforestry systems deserve to be tested or developed for different ecological and social or economic conditions across the country, such as management of the natural regrowth of local multiple-use species as applied with the traditional system of fallow enrichment (Nkunku) in the Lower Congo.

International audience ; Kinshasa, the capital of the Democratic Republic of the Congo, has some 8 million inhabitants and is mainly surrounded by savanna and patches of degraded forest. Estimated fuelwood consumption is in the range of 3 to 6 million tones of fuelwood equivalent per year (representing 0.6 to 1.2 MT of charcoal per year if all the wood were charcoaled). The Mampu project was designed as the pilot phase of a reforestation project covering 100 000 hectares of sandy soil on the Bateke plateau and aiming to remedy wood and charcoal scarcities. Despite the conflicts, about 8000 hectares of Acacia auriculiformis were planted, mainly from 1987 to 1993. From about 1994, the Mampu plantation was divided into 25 hectare plots for 320 farming families. Cultivation mainly follows the agroforestry pattern based on improved fallows, which draws on traditional slash-and-burn farming. Total charcoal production from the plantation varies from 8 000 to 12 000 tonnes per year, in addition to 10 000 T/year of cassava, 1 200 T/year of maize and 6 T/year of honey. The success of the project is an incentive to apply the model to the savanna lands on the Bateke plateaus, taking traditional land rights into consideration and continuing activities to diversify and process production locally. This will help to cover a larger share of urban needs for renewable energy while also creating rural employment. However, other agroforestry systems deserve to be tested or developed for different ecological and social or economic conditions across the country, such as management of the natural regrowth of local multiple-use species as applied with the traditional system of fallow enrichment (Nkunku) in the Lower Congo.

More than three hundred years ago the nutmeg groves of Buru Island were burnt by the soldiers of the Dutch East Indies Trading Company. Fruit dissolved to ash; seeds, carried away by the wind, landed on barren earth. A savanna formed and the island's nutmeg trade was wiped out forever. Forced to leave their coastal settlements, the island's inhabitants were gradually absorbed in the embrace of the forest. They became hunters and gatherers; their only farming implement, a kind of spear used to poke holes in the soil. Arab traders who visited the island called these people 'Alfuru,' 'the people of the interior.' Over the course of three and a half centuries little changed on this island. It was a stagnant world of malaria, filariasis, tiling ringworm, parasites and tuberculosis, a continuum of intertribal warfare and intervillage disputes. And then there came a most historic time, August 1969, when Buru Island became a prison camp for more than 10 thousand political prisoners.

Chapter 1. The Ecology of Browsing and Grazing II -- Chapter 2. The palaeontology of browsing and grazing -- Chapter 3. The paleoecological impact of grazing and browsing: consequences of the late Quaternary large herbivore extinctions -- Chapter 4. Morphological and Physiological Adaptations for Browsing and Grazing -- Chapter 5. Feeding ecology of large browsing and grazing herbivores -- Chapter 6. Population dynamics of browsing and grazing ungulates in the Anthropocene -- Chapter 7. Community dynamics of browsing and grazing ungulates -- Chapter 8. Weather and Climate Impacts on Browsing and Grazing Ungulates -- Chapter 9. Impacts of browsing and grazing ungulates on soil biota and nutrient dynamics -- Chapter 10. Effects of grazing and browsing on tropical savanna vegetation -- Chapter 11. Impacts of browsing and grazing ungulates on plant characteristics and dynamics -- Chapter 12. Impacts of browsing and grazing ungulates on faunal biodiversity -- Chapter 13. Interactions between fire and herbivory: current un-derstanding and management implications -- Chapter 14. Managing Browsing and Grazing ungulates -- Chapter 15. The ecology of browsing and grazing in other vertebrate taxa -- Chapter 16. Browsers and grazers drive the dynamics of ecosystems

Cover -- Half Title -- Title -- Copyright -- CONTENTS -- Introduction -- Evolution & -- Ecology -- GLOSSARY -- Natural selection -- Making new species -- Counting species -- Profile: Daniel H. Janzen -- Habitats & -- niches -- Life history trade-offs -- Behavioural Ecology -- GLOSSARY -- Sexual selection -- Mating systems -- Costs of reproduction -- Defence & -- counter-defence -- Group living -- Kin selection -- Profile: William D. Hamilton -- Population Ecology -- GLOSSARY -- Population distributions -- Dispersal -- Limits to population growth -- Profile: Paul R. Ehrlich -- Cycling populations -- Metapopulations -- Eating . . . -- . . . And being eaten -- Parasites -- Competition -- Mutual benefits -- Communities & -- Landscapes -- GLOSSARY -- Energy flows -- Nutrient cycles -- Keystone species -- Indirect effects -- Disturbance & -- resilience -- Ecological succession -- Species-area relationship -- Island biogeography -- Profile: Robert H. MacArthur -- Biomes & -- Biodiversity -- GLOSSARY -- Global patterns of biodiversity -- Oceans -- Freshwaters -- Tundra & -- boreal forests -- Temperate forests & -- grasslands -- Tropical forests & -- savanna -- Profile: Wangari Maathai -- Deserts -- Applied Ecology -- GLOSSARY -- Valuing biodiversity -- Ecosystem services -- Soil ecology -- Pollination & -- society -- Biological control -- Vectors of disease -- Overharvesting -- Conservation biology -- Profile: Rachel Carson -- Ecology in a Changing World -- GLOSSARY -- The sixth mass extinction -- Climat echange -- Urban ecosystems -- Human-wildlife conflict -- Profile: Raman Sukumar -- Nature-deficit disorder -- Rewilding -- Appendices -- Resources -- Notes on contributors -- Index -- A -- B -- C -- D -- E -- F -- G -- H -- I -- J -- K -- L -- M -- N -- O -- P -- R -- S -- T -- U -- V -- W -- Z -- Acknowledgements.

Intro -- CLIMATE CHANGE AND FOREST ECOSYSTEMS -- Library of Congress Cataloging-in-Publication Data -- CONTENTS -- PREFACE -- Chapter 1: CARBON SEQUESTRATION ANALYSIS FOR CANFOR TFL48 FROM THE CANADIAN BUDGET MODEL FOR THE FORESTRY SECTOR (CBM-CFS3) -- ABSTRACT -- INTRODUCTION -- THE CARBON BUDGET MODEL FOR THE CANADIAN FOREST SECTOR (CBM-CFS3) -- CBM-CFS3 MODEL RESULTS FOR CANFOR TFL48 -- CONCLUSION AND DISCUSSION -- ACKNOWLEDGMENTS -- REFERENCES -- Chapter 2: SIMULATION MODELING TO ADDRESS CLIMATE CHANGE VULNERABILITY AND ADAPTATION PLANNING IN A SASKATCHEWAN FOREST ECOSYSTEM -- ABSTRACT -- INTRODUCTION -- VULNERABILITY AND CLIMATE CHANGE -- VULNERABILITY MODELING -- PREDICTED IMPACTS AND MODELLING RESULTS -- DEVELOPING ADAPTATION OPTIONS -- CONCLUSION -- REFERENCES -- Chapter 3: SHELTERBELTS ON SASKATCHEWAN FARMS: AN ASSET OR A NUISANCE -- ABSTRACT -- INTRODUCTION AND BACKGROUND -- RESEARCH METHODS -- RESULTS -- CONCLUSION AND DISCUSSION -- ACKNOWLEDGMENT -- REFERENCES -- Chapter 4: INDIGENOUS PHILIPPINE AETA MAGBUKÚN TRIBE'S TRADITIONAL FOREST USE AND ADAPTATION TO ENCROACHING CULTURES, LAND USES AND CASH-BASED AGRICULTURE AND FORESTRY -- ABSTRACT -- INTRODUCTION -- EARLY CULTURAL ADAPTATION -- ADAPTATION OF TRADITIONAL AND NEW INFLUENCES -- CONCLUSION -- REFERENCES -- Chapter 5: DETECTING LOGGING ROADS AND CLEARCUTS WITH TERRASAR AND RADARSAT DATA -- ABSTRACT -- INTRODUCTION -- STUDY AREA -- RESEARCH METHODS -- RESEARCH RESULTS AND DISCUSSIONS -- CONCLUSION AND RECOMMENDATIONS -- ACKNOWLEDGMENTS -- REFERENCES -- Chapter 6 CHARCOAL FROM SAVANNA WOODLANDS IN A REDD STRATEGY: CASE OF SUDAN -- ABSTRACT -- INTRODUCTION -- LITERATURE REVIEW -- RESEARCH METHODS -- RESULTS AND DISCUSSION -- CONCLUSION -- ACKNOWLEDGMENTS -- REFERENCES -- Chapter 7: EVALUATION OF FOREST SOIL ENVIRONMENTAL PARAMETERS THAT INFLUENCE CARBON SEQUESTRATION POTENTIAL.