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Over the years, cultural, economic and social factors have led to the development of distinct cultural landscapes in and around the villages of the highlands of southwestern Saudi Arabia. Through centuries, the local inhabitants perpetuated this cultural landscape through subsistence agriculture and managed local natural resources through consensus-driven institutions. This paper describes the changes that have taken place with regard to the cultural landscape in a village of Asir province of Saudi Arabia. This community has recently experienced profound changes in its social, cultural, administrative and technical conditions. The situation of this and similar villages in this province is a particularly clear and interesting case of a general phenomenon of structural change in society interacting with the physical environment producing attitudinal and consequently physical changes in the field of environmental identity particularly at the macro-level. Recent economic growth in Saudi Arabia and an opening of the village of Alckas to outside influences has placed the future of this cultural landscape in doubt. The paper explores the basis of new values and examines some of the conflicts which will need to be resolved. Alckas cultural landscape continues to reflect the local identity of the place and residents and represents the regional characteristics of the highlands of southwestern Saudi Arabia.
The aim of the calculations in this paper was i) to estimate the effect of measures to reduce nitrogen leaching from arable land and ii) to estimate what reduction in the gross load from southern Sweden could be expected. The measures taken were i) cultivation of a catch crop in spring cereals; ii) smaller applications of fertilizer-N to crops in cultivation systems without manure; iii) spring application of manure and a smaller amount of complementary fertilizer-N; and iv) a catch crop in combination with spring application of manure and a reduced rate of fertilizer-N. The models used were the mechanistic SOIL/SOILN models describing water, heat, and nitrogen flows in the soil profile. The largest reduction in leaching was obtained with the combination of catch crop, spring application of manure and reduced rate of fertilizer-N. Total gross load decreased with 16% in this scenario. The catch crop scenario reduced gross load by a mere 5% because it was only introduced in 30% of the acreage of spring cereals. The scenario with a 10% reduction in fertilizer-N resulted in a decrease in load of about 6000 tonnes, i.e. 11%, as well as a yield decrease of about 10%.
Vertical upflow wetland systems have shown high nutrient removal efficiencies. The removal of nutrients (N and P) from wastewater was investigated in a vertical upflow wetland system in Piracicaba, Brazil. The concentration removal was 93% for phosphate, 78% for nitrate and 50% for ammonia. Effective phosphate removal was observed in the top soil layer which has a high surface adsorption area. Nitrate was removed satisfactory at low loading rates due to plant uptake and denitrification. Removal of ammonia was concentration dependent and decreased at high inflow concentrations. Spatial sampling through the bed showed that the treatment efficiency was not uniform. The possibility of the recycling of nutrients as a soil improver or animal feed is an important feature of this type of vertical flow wetland system.
Specialists in tropical rain forest conservation have recently begun to suggest that forests facing imminent destruction in deforestation ‘hot spots’ can not be saved, and that conservation organizations would use their resources more effectively if they focused on preserving ‘cold spots’, remote places with intact rain forests. The advocates of the cold spot strategy contend that sustainable development efforts in deforestation ‘hot spots’ are ineffective. A case study of sustainable development in a rapidly deforesting region of coastal Ecuador questions this contention. Sustainable development in this region takes two organizational forms, one focused on the adoption of sustainable forestry techniques in a small set of villages and the other centered around the creation of a civic arena for discussing and resolving regional sustainable development issues. This two-pronged effort has achieved some success and may provide a model for sustainable development in places experiencing rapid tropical deforestation.
Deforestation has been occurring in Ethiopia for millenia and has accelerated during the last century. On the other hand, historical accounts indicate that restricted afforestation of mountainous areas was initiated already 550 years ago. One of these areas was the Menagesha Forest. To reconstruct forest site history, soil samples from the Menagesha Forest and Wendo-Genet areas were analyzed for 13C natural abundance and C concentration. In soils from Menagesha, δ13C values ranged from −17‰ to −23‰ in the deeper horizons, and from −24‰ to −27‰ in the surface mineral soils and litter layer. This indicates that C4 grasses were once an important component of this ecosystem, and supports the historical accounts. In the Wendo-Genet area, δ13C values ranged from −16‰ to −14‰ in the deeper horizons, and from −23‰ to −16‰ in the topsoil in both cultivated lands and forested sites, suggesting more recent shifts from grassland to woodland or forest. With regard to reforestation and soil conservation, it is encouraging that productive forest with high soil organic carbon concentration could be established on the steep slopes at Menagesha. The study also shows that Ethiopian forest history is more complex than commonly appreciated, and that there has not been a simple unbroken trend of deforestation.
This paper reviews the knowledge on crowberry (Empetrum nigrum ssp. nigrum and ssp. hermaphroditum) dominated ecosystems in the Nordic region. Empetrum leaves and litter have high phenolic content resulting in slow decomposition, and with the formation of an organic top soil, nutrients are kept in an organic nutrient bank in the soil mainly available for plants with ericoid mycorrhiza. Empetrum nigrum ssp. hermaphroditum is a strong nutrient competitor and outcompetes most plants in late successional stages. This is due to chemical interference (allelopathy) and resource competition. Crowberry as an organism is resistant to atmospheric pollution and may even increase in vigor by high atmospheric N deposition in nemoral coastal heaths, but is very sensitive to mechanical disturbances and fire. However, there are indications that the closed nutrient cycle established when Empetrum is dominant may be disturbed after airborne inputs of inorganic N.
Energy consumption in the various stages of the food chain, provides a reasonable indicator for the environmental impact in the production of food. This paper provides specific information on the energy requirement for the main alternatives in each production stage, which should allow the identification of improvement options. One observation is that there seems to be a remarkable relationship between energy requirement throughout the production chain and market value. Products with a high added (emotional) value, e.g. wine, season fruits, and coffee, deviate from the abovementioned relationship. However, that deviation may be overcome when the emotional value is included in the functional unit of the food product. It is concluded that there seems to be no systematic environmental benefit for home-made over industrially produced food. For all food categories, there is a wide variety in energy requirement due to three major factors, viz. season of consumption (fresh versus import and glasshouse production), scale of preparation (home-made and industrial scale) and consumer preference (meat versus vegetable food).
Only about a dozen species of animals are known to achieve maximum ages (Amax) exceeding 100 yrs, including the freshwater pearl shell (Margaritifera margaritifera). This species has a life-span of between 100–200 years depending on latitude and environmental conditions. The difference in Amax is 3–7 times when southern populations, with Amax of 28–40 yrs, are compared to northern Arctic populations, with Amax of 114–190 yrs. Evolutionary and ecological explanations for longevity in the Arctic pearl shell include adaptations to the severe, unstable climatic and hydrological conditions in rivers. Extreme longevity seems to be related not only to the low metabolic rate in the cold climate, but the species can reduce energy expenditure for growth, and can rapidly increase metabolic rate up to 130x the normal level, to regenerate damaged shell or tissue. The physiology of this species may provide valuable clues to understanding the mechanisms that sustain longevity and retard senescence.
The coexistence of hurricanes, coral reefs, and rainforests in the Caribbean demonstrates that highly structured ecosystems with great diversity can flourish in spite of recurring exposure to intense destructive energy. Coral reefs develop in response to wave energy and resist hurricanes largely by virtue of their structural strength. Limited fetch also protects some reefs from fully developed hurricane waves. While storms may produce dramatic local reef damage, they appear to have little impact on the ability of coral reefs to provide food or habitat for fish and other animals. Rainforests experience an enormous increase in wind energy during hurricanes with dramatic structural changes in the vegetation. The resulting changes in forest microclimate are larger than those on reefs and the loss of fruit, leaves, cover, and microclimate has a great impact on animal populations. Recovery of many aspects of rainforest structure and function is rapid, though there may be long-term changes in species composition. While resistance and repair have maintained reefs and rainforests in the past, human impacts may threaten their ability to survive.
Species extinction and gene erosion are still widespread in spite of numerous national and international efforts and conventions. It is now clear that only through symbiotic partnerships between local communities and civil society organizations, industrial enterprises, and government and academic institutions that we can implement effectively the triple goals of the Convention on Biological Diversity, namely conservation, sustainable use and equitable sharing of benefits. This paper describes the approach adopted by the author and his colleagues in India to promote a community-led integrated gene management system.