Clipping, From a College Friend

Congratulatory letter to Brandenburg about his Silver Anniversary from Walter A. Huxman, Governo

In the world, but not of it : Mennonite rhetoric in World War I as an enactment of paradox

Dissertation (Ph.D.)--University of Kansas, Communication Studies, 1987

Reproductive and growth responses of Mojave Desert plants to a changing climate

Global change may impact terrestrial ecosystems through effects on the regenerative capacities of plants. Changes in energy allocation to reproduction, as a result of increasing CO2, changing temperature or precipitation, could shift the ecological and evolutionary factors that control plant distributions and species interactions. These changes in energy allocation to reproduction are manifested as seed number, viability and mass change. We conducted a meta-analysis of results from a number of different elevated CO2 experiments with the goal of determining patterns of reproductive response across a large number of species and functional types. In addition, we performed a number of experimental studies that evaluated the patterns of allocation to reproduction in the context of adult performance and offspring consequences. The relative biomass allocation to reproduction is not consistently affected by exposure to elevated CO2. Accordingly, total seed production generally increases, while seed mass decreases upon exposure to elevated CO2, but the response is dependent upon plant functional type. Nitrogen-fixing plants do not exhibit reduced seed mass at elevated CO2, but may actually show enhancement. Changes in seed characteristics based on functional type suggest that the nitrogen economy of plants at elevated CO2 is very important in combination with alterations of allometric relationships, such that both result in potential life history consequences. CO2-affected changes in reproductive characters may have important implications for species distributions and trophic interactions in natural and agricultural ecosystems

Ecohydrological implications of woody plant encroachment

Journal ArticleIncreases in the abundance or density of woody plants in historically semiarid and arid grassland ecosystems have important ecological, hydrological, and socioeconomic implications. Using a simplified water-balance model, we propose a framework for conceptualizing how woody plant encroachment is likely to affect components of the water cycle within these ecosystems

Partitioning of evapotranspiration and its relation to carbon dioxide exchange in a Chihuahuan Desert shrubland

Key to evaluating the consequences of woody plant encroachment on water and carbon cycling in semiarid ecosystems is a mechanistic understanding of how biological and non-biological processes influence water loss to the atmosphere. To better understand how precipitation is partitioned into the components of evapotranspiration (bare-soil evaporation and plant transpiration) and their relationship to plant uptake of carbon dioxide (CO2) as well as ecosystem respiratory efflux, we measured whole plant transpiration, evapotranspiration, and CO2 fluxes over the course of a growing season at a semiarid Chihuahuan Desert shrubland site in south-eastern Arizona. Whole plant transpiration was measured using the heat balance sap-flow method, while evapotranspiration and net ecosystem exchange (NEE) of CO2 were quantified using the Bowen ratio technique

Bacanora and Sotol: So Far, So Close

El propósito de este trabajo es familiarizar al lector con algunos aspectos relacionados, no sólo con dos bebidas alcohólicas de profundo arraigo en la cultura rural del México norteño, sino también con Agave angustifolia, conocido en Sonora como “agave (o mezcal) bacanora”; y un grupo de especies del género Dasylirion, conocido en México como “sotoles”, y “desert spoon” o ¨cuchara del desierto¨ en los Estados Unidos de América. Ambas comparten múltiples características morfológicas, fisiológicas y ecológicas que les permiten vivir en ambientes áridos. De igual forma, también intenta señalar aspectos únicos de las dos denominaciones de origen que protegen la elaboración de esas bebidas y que han surgido en los albores de este siglo, así como a las normas que rigen su elaboración

Hysteresis of soil moisture spatial heterogeneity and the “homogenizing” effect of vegetation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94935/1/wrcr12475.pd