Browsing by Author "Miller, Jennifer A."
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Item Biogeography of upland bird communities in the Peruvian Amazon(2009-12) Pomara, Lazarus Yates; Young, Kenneth R.; Barth, Robert H.; Dull, Robert A.; Miller, Jennifer A.; Ruokolainen, KalleThe western Amazon is known to be one of the most biologically diverse regions in the world, yet information about the spatial distribution of that biodiversity and the processes governing its distribution remains scarce. An improved understanding of those biogeographic patterns and processes can inform conservation and development planning in areas where anthropogenic landscape change is ongoing. Spatial components of biodiversity are known to be influenced by historical and present-day physical and human geographic processes. There is evidence that major Amazonian rivers form the boundaries of biological regions, at least for birds. Other factors that may influence bird species composition include the dispersal limitations of individual species, forest plant species composition and structure, topography, forest fragmentation, and hunting. Sites where bird species composition was measured in this study represented mature, upland forest on both sides of the Amazon River, and a range of non-flooded forest types, as indicated by soil and plant surveys. Bird species compositional variation was closely correlated with variation in plant species composition, human disturbance associated with forest fragmentation, and position north or south of the Amazon River. The strongest differences were between opposite sides of the river, even though local environments, including plant composition, were not different on the two sides. This strongly suggests that historical biogeographic factors, rather than present-day environmental gradients, are responsible for bioregional boundaries at Amazonian rivers. The difference between plant and bird distributions at this scale underscores the pressing need to re-evaluate general notions of bioregional complexity and pattern in the Amazon basin. Locally, the influence of habitat fragmentation on animal communities, including reduced species richness, was confirmed. The influence of local floristic variation is of particular importance due to its ubiquity across western Amazonia. Thus, understanding the distributions of soils and vegetation is critical for explaining Amazonian animal diversity. The use of these factors to model bird community heterogeneity contradicts assumptions that the processes shaping Amazonian animal community diversity are too complex to measure efficiently, and their use contributes a new understanding of the dimensions of that diversity.Item The changing climate of vulnerability, aid and governance in Malawi(2012-05) Malcomb, Dylan Wayne; Crews, Kelley A.; Young, Kenneth R.; Miller, Jennifer A.By year 2020, developed countries pledged to mobilize USD100 billion per year towards mitigation of greenhouse gases and strategies of adaptation. This redistribution from Annex I (developed) countries to developing countries represents a near doubling of current official development assistance levels, yet future strategies of adaptation remain nebulous. Definitions, opinions and agendas of adaptation have evolved into new global development strategy, but will externally-designed strategies threaten an adaptive process that should be community-led and environmentally-contextual? Little empirical research has been conducted on adaptation as an international development strategy that consists of massive earmarking of funds to institute and later demonstrate that projects are related to climate change. Through semi-structured interviews with international and development organizations, national and local governments, civil society and community focus groups, this research chronicles Malawi's polycentric response to climate change vulnerability. Using site-visits to numerous active adaptation projects in Malawi as case-studies, this research examines who the stakeholders are in this process, what adaptation looks like and how the overall concept of this new development strategy can be improved.Item Forest diversity and conservation in the western Amazon based on tree inventory and remote sensing data(2011-12) Wang, Yung-ho Ophelia; Young, Kenneth R.; Crews, Kelley A.; Miller, Jennifer A.; Sarkar, Sahotra; Pitman, Nigel C.This dissertation contributes to debates in conservation biogeography by examining the spatial heterogeneity of local and regional tree diversity feature using ground and remotely sensed data, and by taking approaches to design a spatially explicit landscape zonation map for future conservation planning in western Amazon, one of the most biodiverse regions on Earth. Fine scale tree diversity and conservation-related studies took place in tropical rainforests in southeastern Ecuador, whereas coarse scale tree diversity research was conducted using data from eastern Ecuador and northern Peru. The lack of species assemblages within three 1-ha tree inventory plots in southeastern Ecuador and the weak correlations with biophysical environment implied that neutral processes may contribute to species diversity. In contrast, differences in species assemblages between plots corresponded to relative geographic locations of the plots, indicating that geographic distance or dispersal limitation may play an important role influencing diversity patterns at a regional scale. Species of high local abundance was found in 1-ha tree inventory plots in western Amazon. Changes in density of locally abundant species between western and eastern plots indicated that some species may have limited distributions. Shifts in species dominance and the significant relationship between floristic variation and geographic distances between plots implied dispersal limitation. Variation in rainfall showed significant relationship with species composition. Therefore, dispersal limitation and precipitation seasonality are potentially the most significant factors that contribute to spatial differences in tree diversity in western Amazon. Characteristics of canopy shadows and palm stem density based on fine-resolution aerial photographs were characterized as exploratory analyses to extract alpha and beta diversity features using remotely sensed data. A zonation map design using multispectral habitat classification and other remote sensing data performed well in its spatial arrangement when potential indigenous land use was integrated. Based on the results of analyses for conservation biogeography, this dissertation concludes that local and regional tree diversity may be influenced by dispersal limitation and seasonality, and that the application of remote sensing for biodiversity conservation is feasible in very species-rich forests.Item Tree ferns of Central Veracruz : harvest and conservation implications(2011-08) Vázquez-Domínguez, Othoniel; Doolittle, William Emery; Knapp, Gregory W.; Miller, Jennifer A.Tree ferns are listed as endangered species under Mexican law and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Despite this status, tree ferns are currently being harvested by rural communities, and sold in the form of handicrafts, traditional medicines, and household ornaments In the state of Veracruz, some authors argue that the harvesting of tree fern caudexes (trunks) to obtain a material made out of the fern’s adventitious roots called maquique poses a major threat to tree fern conservation. This thesis systematically explores the effect of harvesting activities on the distribution of tree fern species in the tropical montane cloud forest’s fragmented landscape using vegetative regeneration as a proxy for maquique harvesting. The study was conducted in El Zapotal in the municipality of Acajete and El Riscal in the municipality of Coatepec, two small communities with different land use histories. A census was performed at each site to georeference and document all tree fern individuals, including information on diameter, height and presence/absence of vegetative regenerations due to maquique harvesting per individual tree fern. Four species were present in the study: Alsophila firma, A. tryoniana, Cyathea bicrenata, and C. fulva. ArcGIS Desktop was used to calculate distances from individual tree ferns to trails and rivers, which were regarded as points of access for maquique harvesters. These data were used to infer how and whether maquique affects the distribution and abundance of tree fern species at the two studied sites. This study reports for the first time different forms of vegetative regenerations in Mexican tree fern species such as the resprouting of multiple branches from a single tree fern trunk and also documents different forms of harvesting like the “C cut”. Contrary to common conservation arguments, the study shows that tree ferns can continue to thrive even after a severe environmental modification, such as forest clearing and the establishment of tree plantations. Other results suggest that maquique harvesters operating clandestinely are more likely to target tree ferns with maquique closer to points of access (trails or rivers) rather than according to size. In the long run, this pattern of tree fern harvesting could modify the distribution of tree ferns as they are displaced from areas closer to human access, despite the ability of some tree fern species to regenerate in highly disturbed environments. The discovery of tree fern regenerative properties offers potential for the management of certain tree fern species as umbrella species for conservation in central Veracruz. It suggests that maquique harvesting might be sustainable given careful management and government regulation based on scientific data.