Identifying a suitable combination of classification technique and bandwidth(s) for burned area mapping in tallgrass prairie with MODIS imagery

Prescribed fire is crucial to the ecology and maintenance of tallgrass prairie, and its application affects a variety of human and natural systems. Consequently, maps showing the location and extent of these fires are critical to managing tallgrass prairies in a manner that balances the needs of all stakeholders. Satellite-based optical remote sensing can provide the necessary input for this mapping, but it requires the development mapping methods that are specific to tallgrass prairie. In this research, we devise and test a suitable mapping method by comparing the efficacy of seven combinations of bands and indices from the MODIS sensor using both pixel and object-based classification methods. Due to the relatively small size of many prescribed fires in tallgrass prairie, scenarios based on the 250 m spatial resolution red and NIR bands outperformed those based on the coarser 500 m spatial resolution bands, and a combination of both red and NIR performed better than each 250 m band individually. Object-based classification offered no improvement over the pixel-based classification, and performed poorer in some cases. Our results suggest that mapping burned areas in tallgrass prairie should be done at a minimum of 250 m spatial resolution, should used a pixel-based classification technique, and should use a combination of red and NIR

A multi-scale examination of the distribution and habitat use patterns of the regal fritillary

Master of ScienceDivision of BiologyDavid A. HaukosThe regal fritillary (Speyeria idalia) was once an abundant butterfly species of North American prairie communities. Despite its once broad geographic distribution, populations have declined by ~99% in the prairie region for reasons that are poorly understood. The rapid, range-wide declines and persistent threats to extant populations from habitat loss and mismanagement prompted the U.S. Fish and Wildlife Service to initiate a species status review of the regal fritillary as a potential candidate for listing under the endangered species act in September 2015. Due to the uncertain status and contention regarding the effects of management practices (i.e., burning, grazing, and haying) on regal fritillary, my research objectives were to assess the effects of management practices and habitat features on the distribution and density of regal fritillary and their preferred larval host plant for the Midwest, prairie violet (Viola pedatifida). I generated species distribution models (SDM) of prairie violet to readily identify potential areas across the landscape containing patches of host plants and subsequently facilitate the location of regal fritillary larvae. The SDM produced maps of the probabilistic occurrence distribution of prairie violet throughout my study area and highlighted habitat features and management practices important to the occurrence of prairie violet. The seven final variables used to create the SDM and identified as important to the occurrence of prairie violet were elevation, slope, hillshade, slope position, land cover type, soil type, and average fire frequency. Using the SDM for prairie violet, I located eight areas to conduct surveys for regal fritillary larvae that were managed using various management (grazing and haying) regimes and fire-return intervals (low ≥ 10 years, moderate 3-5 years, and high 1-2 years). I used a binomial generalized linear model to determine the effects of management, host plant density, months since burn, and the interaction between months since burn and management on the occurrence distribution of regal fritillary larvae. My results indicate that greater host plant density and short fire-return intervals are important to the occurrence of regal fritillary larvae and, despite current management recommendations, larvae may be negatively impacted by a lack of fire. Finally, I surveyed tracts of prairie with my study area using a distance sampling approach along line transects stratified by overall management (burned, grazed, and hayed) and fire-return interval (low ≥10 years, moderate 3-5 years, and high 1-2 years) for adult regal fritillary. My results indicated that adult density was at least 84% greater in areas that received moderate fire-return intervals and greatest in areas that were grazed and burned on a moderate fire-return interval. However, density estimates of adult regal fritillary did not differ among overall management practices (i.e., burned grazed, hayed). Additionally, adult density increased as percent cover of grass, litter, and prairie violets increased. In contrast, adult density decreased as percent cover of woody vegetation and forbs increased. These results support the use of prescribed fire in a shifting mosaic or patch-burning practice as a viable management strategy for maintaining and conserving regal fritillary populations within the Flint Hills region

Oil palm expansion and land cover changes in the Peruvian Amazon: implications for forest conservation and fire mitigation

Land cover change is a major challenge for forest conservation in Amazonia. Forest cover loss and anticipated changes in climate are expected to increase fire incidence in Amazonia with detrimental consequences to human health, climate, and natural ecosystems. In this dissertation I developed remote sensing methods to map and quantify land cover changes attributed to oil palm expansion in the Peruvian Amazon between 2001 and 2010. Then I used these results to assess the role of oil palm expansion on achieving dual goals of agricultural production and forest conservation. Finally I developed maps of burned areas and combined them with the land cover data to model the contribution of land cover changes and variations in drought severity to fire occurrence and spread. I found that high yield oil palm expansion can be effective to reduce the use of land for achieving agricultural production but that incentives for expanding plantations outside forests are essential to guarantee forest conservation. Remote sensing methods developed in this work to map annual land cover conversion to oil palm demonstrated that the use of different satellite sensors is essential for a reliable and comprehensive monitoring of oil palm expansion, considering an assessment of the area expanded, the time of conversion and land cover transitions associated with the expansion of both large- and small-scale plantations. Results from the fire models showed that the area and spatial configuration of different land covers can have a significant influence on fire occurrence and spread but that the magnitude and sign of the correlation depend on drought severity, successional stage of regrowing vegetation and oil palm age. The results suggest that the promotion of forest regrowth and the establishment of oil palm plantations outside forests can be effective at reducing fire occurrence and spread when they develop beyond initial stages of growth and are protected during years of severe drought. Overall, irregular and scattered land cover patches can reduce fire spread, but in dry years fire spread can increase in pixels with more irregular and dispersed fallows and secondary forests. This dissertation contributes to understanding the effects of agricultural expansion and land cover changes on forest conservation and fire mitigation in Amazonia. Crop expansion can be a significant threat to forest conservation in Peru and other tropical countries with large forested areas still remaining. Forest conversion to agriculture can also increase landscape flammability in Amazonia, reducing the ability of the system to withstand the pervasive impacts of wildfires. Yet, this work shows that it is feasible to achieve both agricultural production and forest conservation if incentives to expand crops into already cleared lands are set in place. Not only can incentives reduce pressure on forests, but, in the case of oil palm, they also have the potential to mitigate wildfires if plantations are established outside forests and protected while they are young. Mechanisms for promoting forest regrowth could also be effective for fire mitigation if vegetation is protected against fire during dry years and also during early stages of development