In this thesis, I establish and explore the role of phenology in understanding the rapidly changing environment of a subarctic peatland. First, I demonstrate how digital repeat photography can be used to characterize and differentiate distinct plant communities using two years of images. Each habitat is composed of different plant functional groups, promoting the individualistic approach to characterization that near-earth remote sensing tools can provide. The camera-product Relative Greenness successfully characterized interannual variability in seasonal growth for each habitat type. Across habitats, there was a direct relationship between advancement of spring onset and active season growth though this overall pattern showed habitat-specific variance. The camera images were also useful in characterizing the flowering phenology of an ​eriophorum​-rich fen habitat, for which a metric named Intensity was created. These results suggest that employment of phenology cameras in highly heterogeneous subarctic environments is a robust method to characterize phenology on a habitat to species scale. Next, I explored the role that this phenology product has in modeling Net Ecosystem Exchange (NEE) also measured at the field site. I hypothesized that the explanatory power of the phenology index, which is conceptually tied to a measure of photosynthetic capacity, would be tightly linked to the timescale it was used for: At sub-daily timescales, environmental forces would dominate, though when averaged over days to weekly scales, the biology represented through the camera index would be more influential. I show that at multiple time scales the environmental factors outperform the camera index when modeling NEE. Together, these studies begin to explore the applicability of phenology camera systems in subarctic environments.

6 pp. / Originally published: 1998 / This article provides an introduction to repeat color photography and explains how it can be used as an important part of a comprehensive rangeland monitoring program. Reviewed 12/2014. Originally published 05/1998.

Thesis (M.A.)--University of Wyoming, 2008. / Title from PDF title page (viewed on Sept. 3, 2009). Includes bibliographical references (p. 43-50).

Little research has been undertaken into the rapidly expanding genre of rephotography, where many developments have taken place in response to advancing technology. This thesis is practice-based and incorporates long-term fieldwork in Scotland. The primary rephotographic projects undertaken by practitioners in North America are reviewed and their innovative presentation of material to interpret changes to space and place through time, are assessed and analysed. This study considers the application of some of these practices in a Scottish context. The research sets out to collate and explore repetition through the construction of visual narratives and to better understand the representation of change in people and places over time. The narratives unintentionally formed when places are photographed and rephotographed by multiple practitioners are considered along with the establishment and consequences of iconicity. In a Scottish context, the research identifies three major sources of photographs: the closely aligned nineteenth century tourism-generated catalogues of George Washington Wilson and Valentines of Dundee and the Catalogue of the Countryside of Scotland created by Robert Moyes Adam. The overall picture that emerges from the research is one of opportunity with increasing democratic application, improved accuracy and greater ability to present and share results. Rephotography is known to be a powerful tool for the discernment and measurement of visible change and suggests avenues that might inform the interpretation and utility of repeated images. This research provides an overview from which limitations can be assessed or innovative application devised. While comparative monitoring may remain a primary application, projects – some sentimental and reflective - that explore personal experience, memory and loss can be explored with rephotography.

This thesis explores the Natchez Trace Parkway using the method of repeat photography to determine whether or not the design intent of the Trace has changed since its beginning. Based upon fifteen matched pairs of photographs, which are evaluated based on a content analysis matrix, the original design intent, recent design guidelines, and planned land use maps, the degree of change that has occurred along the Trace is measured. Time has wrought inevitable change along the Trace. The changes that have occurred indicate a further effort to preserve the original design intent of the Trace rather than a shifting of the design intent. No change in design intent is evident in the matched pairs of photographs.

Thesis (Ph. D.)--Texas State University-San Marcos, 2006. / Vita. Appendix: leaves 192-193. Includes bibliographical references (leaves 194-213).

Thesis (Ph. D.)--Texas State University-San Marcos, 2006. / Vita. Appendix: leaves 192-193. Includes bibliographical references (leaves 194-213).

Repeat photography, the process of retaking an existing photograph from the same vantage point, can give insight into long-term land cover dynamics. I advance the use of repeat photography to quantify landscape change in two ways: first, I demonstrate that rigorous field and post-processing methods can lead to highly accurate co-registration of images; second, I show that oblique photographs can provide land cover composition information similar to conventional satellite (Landsat) imagery for dominant land cover types, and that oblique photographs are better at resolving narrow or steep landscape features. I then present a novel approach to evaluate long-term biodiversity change using repeat photography: I measure land cover composition in 46 historical and modern photograph pairs in the Willmore Wilderness Park, Alberta, Canada, and use that land cover information as input into species-habitat models to predict the probability of occurrence of 15 songbird species. I show that coniferous forest cover increased over the past century, leading to a homogenization of the landscape which increased the probability of occurrence of forest-adapted species but negatively impacted non-forest-adapted species. / Graduate / 2019-04-18

Aloe pillansii populations in the biodiversity hotspot of the Succulent Karoo in Southern Africa are thought to be under threat of extinction. This study investigated the population at the type locality; Cornell's Kop in the Richtersveld, South Africa. It has been suggested that theft, animal damage and more recently climate change have caused a decline in the population by over 50% in the last decade, however very little is known about this rare species. Repeat photography and surveys were used to analyse life history patterns and dynamics of the population and thus establish what the potential threats to this keystone species actually are. Repeat photography indicates that there have been high rates of adult mortality over the last fifty years (1.8% of the population dies annually), which results in an average predicted lifespan of 39 years for the remaining adult population on Cornell's Kop. However, a recent survey reported that over 40% of the population recorded were seedlings, which weren't found in a 1995 survey, which is indicative of a recent recruitment pulse on Cornell's Kop and that conditions on the hill are still habitable for A. pillansii. Growth analyses suggest that A. pillansii has an average annual growth rate of 20 mm.yr⁻¹, which in tum means that 8 m individuals may be up to 453 years old. This long-lived strategy would require A. pillansii to only recruit infrequently, during periods of high rainfall, in order to sustain a viable population, which is consistent with findings on other large desert succulents. Seedling ages were estimated from their heights and it was found that 50% of the seedlings appear to have germinated five to ten years ago; this is consistent with rainfall records from the area which indicate that rainfall was consistently above the annual average for this same period. The findings indicate that although the adult A. pillansii population is declining, the presence of 30 seedlings suggest that the population is entering a recruitment phase after just coming out of a lengthy senescent phase. Although A. pillansii 's extensive lifespan makes it a potentially useful indicator species of climate change, the evidence presented in this study does not suggest that climate change has affected the dynamics of this population.

Bush encroachment or the thickening of woody vegetation is a phenomenon occurring throughout savannas, which tends to be more pronounced in small protected areas. The consequences of bush encroachment are often negative for the conservation of biodiversity, for the promotion of tourism and the prevention of wildfires. Hence, effective monitoring of woody vegetation and the factors which influence its spread are essential. This is particularly the case for protected areas such as that of Bwabwata National Park (BNP) in north-east Namibia. With a complex land use history and different fire management approaches being adopted throughout the area, the effect of fire on woody vegetation in BNP is currently poorly understood. This study used a 20-year-old repeat photography monitoring project and satellite-based remote sensing products to explore woody cover dynamics in BNP. Results revealed that woody cover has increased by 13% since 1999 in BNP. Furthermore, the results show differences in the structure of woody vegetation. Repeated late dry season fires in the west of the park have driven an increasing dominance of 3m in eastern sections of the park. This influence of different fire regimes spatially across BNP, suggests that local fire management is a significant determinant of woody vegetation change. Woody vegetation change differs spatially across BNP due to frequent late dry season fires prevailing in the west and less frequent earlier season fires occurring in the east. Therefore, in order to reduce the mortality of woody species and conserve heterogenous height structure in the west, a reduction of frequent late dry season fires is required. Early dry season fires are shown to reduce the rate of increasing total woody cover change and, therefore, this fire management strategy arguably contributes towards the reduction of wildfire risk, conservation of biodiversity and promotion of tourism.