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Human-induced Disturbance (human-induced + disturbance)
Selected AbstractsEffects of anthropogenic disturbances on the diversity and composition of the butterfly fauna of sites in the Sango Bay and Iriiri areas, Uganda: implications for conservationAFRICAN JOURNAL OF ECOLOGY, Issue 2008Perpetra Akite Abstract In assessing environmental change, butterflies have been proven as replicable indicators of biodiversity and functional integrity that can be monitored at a range of scales. Butterflies have been identified as important bio-indicators for assessing biodiversity and monitoring ecosystem responses to environmental perturbations. The objectives of this study were to determine changes in the butterfly fauna of differing sites in the Sango Bay Area (SBA) and Iriiri (Karamoja) in comparison with data collected 10 years ago, and to investigate the impact of different degrees of habitat disturbance on butterflies. The general butterfly diversity was determined by trapping and sweep netting along transect lines and by random sweeping. The impact of human-induced disturbance was assessed by comparing species richness and composition between the sites and regressing the weighted disturbances against species diversity per site. There was a marked decrease in species diversity and varied species composition between the two studies and between the habitat types. Charcoal burning and grazing had significant negative correlations with diversity within forest sites (r2 = 0.825, P < 0.05), whereas cultivation and tree cutting/logging had significant negative correlations with diversity of open savannas (r2 = 0.718, P < 0.05 and r2 = 0.999, P < 0.05, respectively). [source] Generation, Capture, and Utilization of Industrial Carbon DioxideCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 3 2010Andrew Abstract As a carbon-based life form living in a predominantly carbon-based environment, it is not surprising that we have created a carbon-based consumer society. Our principle sources of energy are carbon-based (coal, oil, and gas) and many of our consumer goods are derived from organic (i.e., carbon-based) chemicals (including plastics, fabrics and materials, personal care and cleaning products, dyes, and coatings). Even our large-volume inorganic-chemicals-based industries, including fertilizers and construction materials, rely on the consumption of carbon, notably in the form of large amounts of energy. The environmental problems which we now face and of which we are becoming increasingly aware result from a human-induced disturbance in the natural carbon cycle of the Earth caused by transferring large quantities of terrestrial carbon (coal, oil, and gas) to the atmosphere, mostly in the form of carbon dioxide. Carbon is by no means the only element whose natural cycle we have disturbed: we are transferring significant quantities of elements including phosphorus, sulfur, copper, and platinum from natural sinks or ores built up over millions of years to unnatural fates in the form of what we refer to as waste or pollution. However, our complete dependence on the carbon cycle means that its disturbance deserves special attention, as is now manifest in indicators such as climate change and escalating public concern over global warming. As with all disturbances in materials balances, we can seek to alleviate the problem by (1),dematerialization: a reduction in consumption; (2),rematerialization: a change in what we consume; or (3),transmaterialization: changing our attitude towards resources and waste. The "low-carbon" mantra that is popularly cited by organizations ranging from nongovernmental organizations to multinational companies and from local authorities to national governments is based on a combination of (1) and (2) (reducing carbon consumption though greater efficiency and lower per capita consumption, and replacing fossil energy sources with sources such as wind, wave, and solar, respectively). "Low carbon" is of inherently less value to the chemical and plastics industries at least in terms of raw materials although a version of (2), the use of biomass, does apply, especially if we use carbon sources that are renewable on a human timescale. There is however, another renewable, natural source of carbon that is widely available and for which greater utilization would help restore material balance and the natural cycle for carbon in terms of resource and waste. CO2, perhaps the most widely discussed and feared chemical in modern society, is as fundamental to our survival as water, and like water we need to better understand the human as well as natural production and consumption of CO2 so that we can attempt to get these into a sustainable balance. Current utilization of this valuable resource by the chemical industry is only 90,megatonne per year, compared to the 26.3,gigatonne CO2 generated annually by combustion of fossil fuels for energy generation, as such significant opportunities exist for increased utilization of CO2 generated from industrial processes. It is also essential that renewable energy is used if CO2 is to be utilized as a C1 building block. [source] Habitat loss, resource specialization, and extinction on coral reefsGLOBAL CHANGE BIOLOGY, Issue 10 2004Philip L. Munday Abstract Coral reefs worldwide are being degraded because of global warming (coral bleaching) and coastal development (sedimentation and eutrophication). Predicting the risk of species extinctions from this type of habitat degradation is one of the most challenging and urgent tasks facing ecologists. Habitat specialists are thought to be more prone to extinction than generalists; however, specialists may be more susceptible to extinction because (1) they are specialists per se, (2) they are less abundant than generalists, or (3) both. Here, I show that declines in coral abundance lead to corresponding declines in the abundance of coral-dwelling fishes, but with proportionally greater losses to specialists than generalists. In addition, specialists have smaller initial population sizes than generalists. Consequently, specialists face a dual risk of extinction because their already small populations decline more rapidly than those of generalists. Corresponding with this increased extinction risk, I describe the local extinction of one specialist species and the near-global extinction of another species. I conclude that habitat specialists will be the first species lost from coral reefs because their small populations suffer the most from human-induced disturbances. [source] Disturbance affects spatial patterning and stand structure of a tropical rainforest treeAUSTRAL ECOLOGY, Issue 4 2010BRUCE L. WEBBER Abstract The distribution and spatial patterns of plant populations in natural ecosystems have recently received much attention; yet the impacts of human-induced disturbances on these patterns and underlying processes remain poorly understood. We used the sub-canopy tree, Ryparosa kurrangii (Achariaceae), to explore the possible effects of such disturbances on stand structure and spatial patterning in an Australian tropical rainforest. We studied three populations that differed in their extent of habitat modification: anthropogenic disturbance (proximate settlement and roads) and internal damage by an invasive alien species, the feral pig (Sus scrofa). Populations were mapped, characterized, and three size cohorts (seedlings, saplings, trees) were analysed using a suite of spatial point pattern analyses (univariate: Diggle's G and F and Ripley's K; bivariate: Diggle's G and Ripley's K). Ryparosa kurrangii has a typical stand structure for a sub-canopy tree species, but occurs at high densities locally (>400 stems ha,1). At all sites, the tree cohort were randomly distributed and saplings were spatially aggregated at distances of up to 2,3 m. Between sites there were distinct differences in the size structure and spatial pattern of seedlings, the cohort most affected by recent habitat modification. That is, the least disturbed site had no aggregation among seedlings, the site with the greatest anthropogenic disturbance had many small, clustered seedlings that were spatially associated with trees, and the site with pig damage had clustered seedlings that had no spatial relationship with trees. We propose that habitat modification by anthropogenic and pig disturbance disrupts seed dispersal and establishment regimes, which leads to altered seedling spatial patterns. These disturbances could have long-term implications for the population structure and health of R. Kurrangii. [source] | ||||||||||