Although settlement patterns are a central topic of archaeological research, there is a paucity of general theory on the determinants of agrarian settlement. What passes for a theory of agrarian settlement in archaeology is a borrowed model which does not recognize the relationship between population density and agricultural intensity. This dissertation argues that the rules determining where farmers settle are inextricable from how they farm. Ethnohistoric and ethnoarchaeological data are used to investigate the relationship between agricultural change and the determinants of settlement location in the case of the Kofyar, a population of farmers colonizing a frontier area in the central Nigerian savanna. As they moved into an area with a low ratio of population to productive land, Kofyar agriculture was extensified in accord with the Boserup (1965) model. With potentially greater travel costs associated with domestic water than with farm plots, streams exerted a strong attraction to early settlements. With increasing land pressure, the attraction value of farmland eclipsed the attraction to water. Contrary to Boserup's theory that agricultural responses to land pressure cross-cut environments, analysis of settlement histories of over 1000 households shows that responses vary with soil type. Farmers on high-quality sandstone-derived soils tend to intensify cultivation, while farmers on inferior shale-derived and igneous-derived soils tend to abandon their farms when yields begin to decline. The location of Kofyar compounds with respect to each other is closely related to the labor demands of agricultural production. The restricted range of distances between residential compounds reflects the reliance on inter-household collaboration in agricultural production.

The area of land farmed in Africa is predicted to double by the year 2050 yet very few African studies have investigated the impact of different farming intensities and regimes on bird communities. This study examined avian species richness and diversity along with the densities of some common bird species on the Jos Plateau, Nigeria, in relation to habitat features on farmland over a gradient of differing farming intensities. The study area exhibited a variety of different levels of farming which differed in the habitat available for birds. Birds normally associated with savanna woodland were more associated with less intensive farming, and open-country birds were more associated with more intensive sites, with more species of birds observed where farming was less intensive. Common species of birds using cultivated land associated with different crops, with acha and millet being the most commonly used. Tree density was the most important variable predicting avian species richness and diversity, with medium tree density predicting the highest species richness and diversity. The densities of two common farmland birds were predicted best by tree density, but varied in their responses to the habitat variables, with common bulbul, a savanna generalist, associating more with less intensive, wooded areas and red-cheeked cordon-bleu, an open savanna granivore, associating with medium intensity, more open farmland. Whinchats were common in open, intensively farmed areas with few trees and good herbaceous vegetation cover. The data presented indicates the importance of retaining natural features of savanna habitat in farmland in order to maintain high avian diversity on farmland. More detailed studies are needed in order to determine the mechanisms involved in the associations observed and collaborations between ecologists and social scientists will be necessary to develop effective policies to limit the impact of the intensification of agriculture in Africa on avian biodiversity.