Essays on the environment

These essays have been written as part of my environmental science degree.

• Applications of remote sensing to conservation of forest ecosystems — At regional to global scales the only feasible way to monitor the world's forests is through remote sensing. The use of coarse-grain remote sensing techniques for measuring deforestation and fragmentation at regional and global scales in combination with new developments such as neural network classification promises to improve the accuracy of forest extent measurements. The use of techniques such as seasonality in AVHRR data to enable finer differentiation of forest type is still proving problematic and relies on may require improvements in sensor technology before becoming feasible. The improvement in remote sensing techniques, sensor technology and the growing emphasis on conservation are bringing forest ecologists and remote sensing scientists together for the first time. Applications of fine-grain remote sensing techniques to conservation of biodiversity, assessment of protected areas and species protection show that fine-grain remote sensing is underused in conservation of forest ecosystems.
• Competition, behaviour and seed size — There is enormous variation in the size of seeds on vascular plants. The wide range of seed sizes in the natural world can be explained by recognizing seed size as the center of a nexus of strong adaptive forces at different parts of a plants reproductive cycle. Adaptation at the production stage tends to evolve smaller seeds in greater quantity. Adaptation in dispersal is dependent on the mechanisms of dispersal that are available and will sometimes adapt for smaller more easily dispersed seeds and sometimes larger, seeds that are more attractive to vertebrates. Adaptation in establishment, on balance, pressures towards increased seed size for greater survivability. Overall different adaptive forces at different stages in a plant reproductive cycle act to reduce the effective amount of competition between seeds by creating 'niche' plant reproduction pathways.
• Efficient investment of conservation funds — Mainland habitat 'islands', a relatively new concept, is promoted as a way to arrest the ongoing decline, and eventually enhance New Zealand's indigenous biodiversity. Mainland islands aim to restore fully functioning biotic communities with a predominance of indigenous species through active intervention. Assessment of New Zealand current mainland island projects on the triple-bottom line of ecological, social, and economic costs and benefits demonstrates a net gain. By achieving multiple social and environmental goals within an adaptive, integrated management framework, the mainland island projects are delivering substantial value with conservation funds. Further benefits for conservation may be derived by extending social goals and integrating limited economic goals within the mainland island framework. An expansion of the mainland island concept is recommended.
• Forest fragmentation near Tai National Park, Ivory Coast — Tropical deforestation and the consequent destruction and fragmentation of habitat are the primary threats to biodiversity in developing counties today. Satellite imagery is used to study the extent of deforestation in an area centered on the Guiglo-Taï road in southwest Ivory Coast, to the northwest of the Taï National Park. Features including primary forest, secondary forest, bare ground and watercourses are classified. The study area partly encompasses several protected areas. The protected areas are found to have mostly escaped deforestation, however forests outside the protected areas are severely fragmented and degraded.
• Goals and approaches - Optimising interference levels in conserv.. — In order to maximise conservation goals when restoring an ecosystem, management must make choices about the appropriate level of interference within the managed area. Interference levels may range from a zero interference policy through to intensive interference. A selection of different approaches to interference is presented and case studies illustrating each approach are examined. The most suitable approach is dependent on the goals of management. It is concluded that the selected approach will provide a framework for identifying the optimum interference level within specific conservation systems.
• Implications of scale in the study of fragmentation and it effects — Tropical deforestation and the consequent destruction and fragmentation of habitat are the primary threats to biodiversity in developing counties today. Satellite imagery is used to study the extent of deforestation in an area centered on the Guiglo-Taï road in southwest Ivory Coast, to the northwest of the Taï National Park. Features including primary forest, secondary forest, bare ground and watercourses are classified. The study area partly encompasses several protected areas. The protected areas are found to have mostly escaped deforestation, however forests outside the protected areas are severely fragmented and degraded.
• Meadow to megacity - Meeting future needs in an urban environment — There has been considerable interest in determining whether urbanisation is enhancing or degrading the earth's environmental capacity when separated from economic growth and population growth. The environmental sustainability of cities in the developing world is contrasted against cities in the developed world. Results show that sustainability is improved by urbanisation when economic and population growth is constant.
• Wind Energy Conversion Systems - A feasibility report for Mt Grey, North Canterbury — This report investigates the feasibility of Wind Energy Conversion Systems (WECS) on the Mt Grey ridgeline, 15km west of Amberley, in North Canterbury. The feasibility of wind generation at the site is studied in terms of electricity productivity and income, economic cost of energy and environmental impact. Energy productivity and income at the Mt Grey site is estimated using data from two neighbouring climate stations at Ashley forest (distance 7km) and Balmoral (distance 33km). The annual energy production (in 2000) from a hypothetical 660 kW turbine is 2270 MWh. The average electricity price earned from generation at Mt Grey on the spot market is 3.52 cents per kWh. The proposed site at Mt Grey would consist of 5 turbines having a rated power output of 3.3 MW and produce approximately 11.4 GWh of electricity per annum. The total capital costs of $5.1 million and annual operating costs of $58,500 are input into a discounted cash flow analysis with a standard EPRI-TAG annuitisation value of .1079. Cost of energy is calculated to be 5.4 cents per kWh.