This study focuses on modelling community productivity, species abundance and richness, and the impact of climate change and alternative phosphorous fertiliser application strategies on pasture productivity by integration of decision tree and regression modelling approaches with a geographical information system (GIS) in a naturalised hill-pasture ecosystem in the North Island, New Zealand, using data derived from research conducted on hill-pastures over the last several decades. The results indicated that the decision tree models had a high predictive capability and clearly revealed the relative importance of environmental and management factors in influencing community productivity, species abundance and richness. Spring rainfall was the most significant factor influencing annual pasture productivity in the North Island, while hill slope was the most significant factor influencing spring and winter pasture productivity. Annual P fertiliser input and autumn rainfall were the most significant factors influencing summer and autumn pasture productivity, respectively. For species functional group abundance, soil Olsen P was the most significant factor influencing the relative abundance of low fertility tolerance grasses (LFTG) and moss, while soil bulk density, slope and annual P fertiliser input were the most significant factors influencing the relative abundance of legume, high fertility response grasses (HFRG) and flatweeds, respectively. Legume abundance was the most significant factor influencing species richness in the hill-pasture. Species richness increased with an increase in legume abundance and showed a tendency for a hump-shaped response. Grazing animal species also had a significant effect on species richness; pasture grazed by sheep had more species than pasture grazed by cattle. Climate change scenarios of temperature increases of 1-2 °C and rainfall changes of -20% to +20% would have a great impact (-46.2% to +51.9%) on pasture production in the North Island. Pasture in areas with relatively low rainfall had a higher response to increased P fertiliser input than pastures in areas with a relatively high rainfall. In conclusion, the integration of a GIS with decision tree and regression models in this study provided an approach for effective predictive modelling of community productivity, species abundance and richness in the hill-pasture. This modelling approach can also be used as a tool in pasture management such as in assessing the impact of climate change and alternative fertiliser management on pasture production.

In the early 1990s the Intergovernmental Panel on Climate Change predicted that the gravest effects of climate change could be on human migration, as millions would be displaced by coastal erosion, flooding, and drought. Today, this is considered a reality that is coming ever closer. Yet, there are currently no binding international frameworks dedicated to the issue of climate induced migration. In addition, the current regime of international refugee law is woefully inadequate at responding to the issue. Individuals that do not fall under the refugee definition are thus commonly left with the general scope of international human rights law standards, so-called complementary protection.   On these premises, this thesis sets out to examine the circumstances under which the non-refoulement principle in international human rights law could be applied in the context of climate change effects and especially slow onset processes, and how the principle could potentially be developed. Principally through examining jurisprudence concerning the International Covenant on Civil and Political Rights and the European Convention on Human Rights, this thesis finds that while there is a possibility for non-refoulement obligations to arise due to the effects of climate change, the precise scope of such protection is unclear. Although case law has emerged and continues to do so, the complex nature of climate induced migration and the undeveloped jurisprudence on this issue leaves important questions unanswered. This thesis finds that there seems to be no obvious response to the question whether climate change is a relevant factor in the legal analysis of non-refoulement claims, and whether it should be. Furthermore, there are great challenges in discerning the required intensity of harm for the threshold to be met and protection to be granted. In addition, this thesis finds that applying the non-refoulement principle in the context of slow onset processes entails several difficulties, particularly concerning the timing and prediction of the harm. It is therefore concluded that, as long as there is no framework dedicated to the issue of climate induced migration, clarity will be much needed in case law as to the scope of non-refoulement obligations in the context of, especially, slow onset processes due to climate change.