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Fragile Ecosystems (fragile + ecosystem)
Selected AbstractsSignificant Achievements in Protection and Restoration of Alpine Grassland Ecosystem in Northern Tibet, ChinaRESTORATION ECOLOGY, Issue 3 2009Qing-zhu Gao Abstract Alpine grassland is a fragile ecosystem, and a large area of this grassland type has been severely degraded in Northern Tibet, to the extent that it has become the primary ecological problem in the region. Various levels of government, including the national central government, the Tibetan Autonomous Region government, and the Nagqu Prefecture government have worked together to achieve alpine grassland ecosystem protection and prevent grassland degradation. These efforts have resulted in significant ecological, social, and economic benefits in Northern Tibet. [source] Alteration of normal cellular profiles in the scleractinian coral (Pocillopora damicornis) following laboratory exposure to fuel oilENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2006Luc Rougée Abstract Petroleum contamination from oil spills is a continuing threat to our ocean's fragile ecosystems. Herein, we explored the effects of the water-soluble fraction of crude oil on a stony coral, Pocillopora damicornis (Linneaeus 1758). We developed methods for exposing corals to various concentrations of crude oil and for assessing the potential molecular responses of the corals. Corals were exposed to water-accommodated fraction solutions, and appropriate cellular biomarkers were quantified. When compared to the "healthy" control specimens, exposed corals exhibited shifts in biomarker concentrations that were indicative of a shift from homeostasis. Significant changes were seen in cytochrome P450 1-class, cytochrome P450 2-class, glutathione- S -transferase-pi, and cnidarian multixenobiotic resistance protein-1 biomarkers, which are involved the cellular response to, and manipulation and excretion of, toxic compounds, including polycyclic aromatic hydrocarbons. A shift in biomarkers necessary for porphyrin production (e.g., protoporphyrinogen oxidase IX and ferrochelatase) and porphyrin destruction (e.g., heme oxygenase-1 and invertebrate neuroglobin homologue) illustrates only one of the cellular protective mechanisms. The response to oxidative stress was evaluated through measurements of copper/zinc superoxide dismutase-1 and DNA glycosylase MutY homologue-1 concentrations. Likewise, changes in heat shock protein 70 and small heat shock proteins indicated an adjustment in the cellular production of proteins. Finally, the results of this laboratory study were nearly identical to what we observed previously among corals of a different species, Porites lobata, exposed to an oil spill in the field after the grounding of the Merchant Vessel Kyowa Violet. [source] Land cover change and land degradation in parts of the southwest coast of NigeriaAFRICAN JOURNAL OF ECOLOGY, Issue 2009Mayowa Fasona Abstract Frequent alteration in land cover often leads to decreased stability of ecosystems which can also increase the vulnerability of rural communities to externalities of environmental change. This study carried out in parts of the coast of southwestern Nigeria utilized topographic base maps and two-time Landsat TM imageries to assess the trend in land cover changes and ecosystems degradation for the three time periods 1965, 1986 and 2001. Remote sensing, geographic information systems and landscape pattern analysis were employed for data processing and analysis. The focus of the analysis was on land cover change, land degradation, and changes in landscape pattern resulting from interplay of natural and anthropogenic drivers. The results show increased trend in human-induced land cover change with concomitant severe negative impacts on ecosystems and livelihoods. About 98,000ha (30% of the area) was seriously degraded as at 2001. About 33,000ha (10%) was under permanent saline water inundation with about 21 communities already dislocated. Loss of fragile ecosystems including marshland (from 7.7% in 1965 to 1% in 2001) and mangrove (from 14.6% in 1965 to 3.1% in 2001) was intense, while over 300 ponds/small lakes which are important for the local fishing economy have disappeared. About eighteen communities were also dislocated by erosion in a section around the southeastern parts of the coastline. Landscape metrics generated, suggested increased ecosystems perturbation and landscape fragmentation. The paper also discussed the implications of these rapid changes for ecosystems stability, food security and sustainable rural livelihoods in the area. [source] Biodiversity conservation in Mediterranean and Black Sea lagoons: a trait-oriented approach to benthic invertebrate guildsAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2008A. Basset Abstract 1. The extent to which conservation of biodiversity enforces the protection of ecosystem functioning, goods and services is a key issue in conservation ecology. 2. In order to address this conservation issue, this work focused on community organization, linking community structure, as described both in taxonomic and functional terms, to community functioning and ecosystem processes. 3. Body size is an individual functional trait that is deterministically related to components of ecosystem functioning such as population dynamics and energy flow, and which determines components of community structure. Since body size is an individual trait that reflects numerous factors, it is also exposed to trait selection and the niche filtering underlying the community. 4. An analysis of the relevance of body size to community organization in transitional water ecosystems in the eastern Mediterranean and Black Sea regions is presented, based on field research conducted on a sample of 15 transitional water ecosystems. 5. 250 taxa were identified, clumped in five orders of magnitude of body size. All body size patterns showed triangular distributions with an optimal size range of 0.13 mg to 1.0 mg individual body mass. 6. Deterministic components of size structure were emphasized and a hierarchical organization with dominance of large sizes was demonstrated by the slopes of the body size-abundance distributions, consistently larger than the EER threshold (b=,0.75), and by the direct relationship of energy use to body size for most of the body size range. 7. Consistent variations of body size-related descriptors were observed on three main gradients of environmental stress: eutrophication, confinement and metal pollution. 8. The results support the relevance of constraints imposed by individual body size on community organization in transitional water ecosystems and the adequacy of size patterns as an indicator for ecological conservation of these fragile ecosystems. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||