Technologically advanced countries use more than 10,000 chemicals routinely and approximately 1,500 new chemicals are introduced annually (Connell and Miller 1984). While many of these chemicals are harmless, some have catastrophic effects on aquatic ecosystems and show the most severe effects on higher trophic level consumers, including wading birds through bioaccumulation and biomagnification (Ohlendorf et al. 1979, Spalding et al. 1994). The present study is the first to address three primary questions: (1) Can non-sacrificial sampling of wading birds reflect food chain contamination reliably? (2) Are nestling growth rates or other reproductive indices of the birds affected by food chain contamination? (3) Are reproductive indices related to tissue concentrations of contaminants in these birds? Tissues of White Ibis (WI) and Little Blue Herons (LBH) were sampled from a colony of wading birds near Devil's Swamp, an area known to be polluted with organochlorines and heavy metals, and from four other colonies as controls. Eggs, blood, guano, and food samples were analyzed for hexachlorobenzene, hexachlorobutadiene, lead, and cadmium contamination. Eggshells and feathers were also tested for metal content. LBH chicks were measured twice weekly to ascertain growth rates The data indicate for the first time that food chain contamination by heavy metals can be readily assessed from guano samples collected from chicks of both WI and LBH, and demonstrate differences in metal contamination between polluted and control colonies. This was not true for organochlorine contaminants, which were distributed independently of the metals in the environment. These data are also original in establishing a relationship between the presence of cadmium in feathers and reduced growth rates in LBH, and in demonstrating that lead-exposed chicks had increased nestling mortality. The findings of the present study expand our understanding of wading birds as indicators of environmental contamination in several ways: (1) non-sacrificial sampling can reflect food chain contamination by heavy metals; (2) nestling survival and growth rates are affected by exposure to heavy metals in the food chain; and (3) wading birds bioaccumulate metals and their tissues can thus serve as reliable bioindicators of contamination / acase@tulane.edu

Thesis (Ph.D.)--Indiana University, Dept. of Political Science, 2006. / Source: Dissertation Abstracts International, Volume: 67-01, Section: A, page: 0324. Adviser: Elinor Ostrom. "Title from dissertation home page (viewed on Feb. 8, 2007)."

<p>Biodiversity conservation issues are complex and contentious. In this dissertation, I focus on Indian mammal conservation science, management, as well as policy issues that shape these factors. I am particularly interested in, where and which mammals are extinction prone, and what factors promote species persistence in human-dominated landscapes. I examine patterns of extinction, range contraction and current distribution of 25 species of large mammals in India in Chapters 2 and 3. I apply occupancy models to data from a sub-continental scale expert opinion survey. I model species occurrence in relation to ecological and social covariates based on a priori hypotheses about the determinants of mammalian distribution patterns. </p><p>I find that all 25 large mammal species are extinction prone. I find time affects extinction, and conservation initiatives of the last four decades have allowed some species to re-colonize some areas. I find protected wildlife reserves are critically important for persistence of species. Many species with much of their habitat outside existing protected areas will require new protected areas to persist. I find that human population density negatively influences survival probability for species, and human cultural tolerance positively affected persistence of species. Most large-bodied animals, habitat specialists, and rare species had higher extinction probabilities. I find that in addition to protected areas, land use, and human population densities, regionally rooted cultural and religious factors have allowed some species to survive. Conservation strategies must integrate all these factors to ensure the survival of India's large mammals in the future.</p><p>Conservation efforts to protect wildlife in human-dominated landscapes, often requires relocation of people. This policy has rarely been examined in detail. In Chapter 4, I focus on a reserve in India's Western Ghats of India to assess resettlement experiences of people during and after implementation of a relocation project. </p><p>Lastly, the success or failure of conservation policies and management interventions be they for protecting wildlife or addressing needs of local communities, depends substantially on the attitudes of conservation practitioners. In Chapter 5, I examine the attitudes, perspectives and opinions of Indian conservationists towards conservation issues and policies in India.</p> / Dissertation

<p>An increasing number of experimental studies attempt to maximize biomass production of trees in plantations by removing nutrient and water limitations. The results from these studies begin to inform operational managers. We investigated a Populus trichocarpa Torr. x P. deltoides Bartr. & Marsh plantation with a combined irrigation and nutrient supply system designed to optimize biomass production. Sap flux density was measured continuously over four of the six growing season months, supplemented with periodic measurements of leaf gas exchange and water potential. Measurements of tree diameter and height were used to estimate leaf area and biomass production using allometric relations. Sap flux was converted to canopy conductance, and analyzed based on an empirical model to isolate the effects of water limitation. Actual and soil water-unlimited potential CO2 uptakes were estimated using a Canopy Conductance Constrained Carbon Assimilation (4C-A) scheme, which couples actual or potential canopy conductance with vertical gradients of light distribution, leaf-level conductance, maximum Rubisco capacity (Vcmax) and maximum electron transport (Jmax). Net primary production (NPP) was ~0.43 of gross primary production (GPP); when estimated for individual trees, this ratio was independent of tree size. Based on the same ratio, we found that current irrigation reduced growth by ~18 % compare to growth with no water limitation. To achieve this maximum growth, however, would require 70% more water for transpiration, and would reduce water use efficiency by 27 %, from 1.57 to 1.15 g stem wood C kg-1 water. Given the economic and social values of water, plantation managers appear to have optimized water use.</p> / Dissertation

In desert grasslands of the southwestern United States, Prosopis velutina (mesquite), an N-fixing legume, has proliferated from historic drainage locations into more xeric grassland plains. This expansion is forming a more heterogenous soil nutrient topography in grasslands, N-pools are becoming localized under mesquite canopies, yet the rate and extent of this sequestration remains relatively unknown. Repeated prescribed burning has been used to control Prosopis distribution, but effects of fires on grassland soil nutrient distribution and aboveground plant biomass are also largely unknown. I examined recent research concerning P. velutina natural history, emphasizing characteristics that contribute to range expansion. I also evaluated Prosopis management practices---which include herbicide treatment, prescribed burning, grazing reduction, and mechanical removal---and management goals---which involve complete removal, no removal, and limited removal. Of these, limited removal is the most beneficial, using an herbicide application followed by periodic prescribed burning. In 1997 I established a study area at Fort Huachuca Military Reservation in southeastern Arizona, selecting two adjacent sites with similar soil composition and topography but different fire histories. I examined spatial and seasonal changes in composition and distribution of available soil N and litterfall. My results indicated these were more spatially and temporally heterogenous on sites with low fire frequency and high P. velutina stand development. In 1998 I selected nine sites at Fort Huachuca on two upland surfaces located < 1 km apart, with similar soil physical characteristics and fire frequencies ranging from 0 to 5 fires/decade. I evaluated relationships between fire frequency, soil nutrient status (pH, available P, organic C, total N, and available N), and aboveground plant biomass, including that of the non-native Eragrostis lehmanniana (Lehmann lovegrass). Soil pH and ammonium significantly decreased with increased fire frequency on one surface, and available P significantly decreased with increased fire frequency on the other surface. Available P and pH were significantly different between the 2 surfaces, but aboveground biomass was similar. Soil nutrient status and biomass were not related, suggesting plant-available soil nutrients may not control plant distribution or recovery following fire. E. lehmanniana biomass was negatively correlated with native grass and forb biomass, and tended to increase with increasing fire frequency. Surface litter and E. lehmanniana biomass were correlated, and may increase fire frequency, an important consideration when implementing grassland fire management practices.

The effects of land-use history in the Animas Mountains, New Mexico (AM) and the Sierra los Ajos, Sonora (SLA) were studied in relation to morphological and soil chemical characteristics, radial and basal area growth, and forest structure. Litter depth, organic matter, total nitrogen, CEC, and exchangeable cations were greater in the AM than in the SLA, apparently as a result of differences in fire frequency and other land uses. Seasonal precipitation (October-January) was reconstructed for the AM. Annual precipitation (July-July) was reconstructed for the SLA. July PDSI was reconstructed for both mountain ranges. Fires in the AM were preceded by relatively wet conditions two years before the fire year. No significant climate-fire relationship was found in the SLA. Tree radial and basal area increase differed between mountain ranges, suggesting that annual growth was influenced by differences in land-use history. Fire suppression activities and other land uses in the AM apparently have produced an increase in tree density and dominance of shade-tolerant but less-fire resistant species (i.e. Douglas-fir, southwestern white pine, pinyon pine). More frequent fires and logging activities in the SLA apparently have produced lower tree densities and dominance by shade-intolerant ponderosa pine.

Between 1960 and 1991, the population of Rondonia, Brazil increased from 70,000 to 1.3 million. This increase occurred during the thirty-year period bracketing the rise to statehood, during which a rural population also became largely urban. Simultaneously, the loss of tropical rain forest in the state progressed at unparalleled rates. This dissertation examines some of the ways in which these two rapidly changing aspects of Rondonia's landscape are related to each other. The research project employs a framework grounded in realist philosophy, a flexible approach that facilitates research into processes that are unfolding at a regional scale but which occur within the context of broader national and international structures. Several kinds of connections between urban population growth and deforestation are examined, including land conversion for urban use, food consumption in urban areas, wood consumption for housing in urban areas, and power consumption in urban areas. Urban sprawl is found to be significantly and positively correlated with deforestation at the municipio level, but the absolute magnitude of urban sprawl is very small relative to total deforestation. No spatial correlation is found between urban settlement and the dedication of land to food crops. A weak but positive correlation is found between urban demand for timber and total deforestation, but the absolute magnitude of local timber demand is found to be very small in comparison to forest clearing. The recent diversification of the timber industry in order to absorb urban labor may have profound implications for demand on forest resources in the future. Electricity generation has been destructive of rain forest, and capacity already under construction is likely to have further such impacts. The cultural landscape of Rondonia reflects an orientation that is increasingly outward-looking. Rondonia's cities and towns are becoming more closely connected with one another and more fully integrated with the outside world. Early incentives to settle in Rondonia contributed to deforestation, but the curtailment of these incentives did not curtail deforestation. Rondonia is a place caught between two opposite pressures: the pressure to preserve the rain forest and the pressure to participate in the world economy as consumers.

<p> The western corn rootworm, or WCR, (<i>Diabrotica virgifera virgifera </i> LeConte) is the most significant pest of field corn (<i>Zea mays</i>) in the United States, and has recently expanded its range into Europe. Since 2004, hybrid corn containing Bt toxins targeting the corn rootworm complex have been heavily adopted and are now the primary control measure for this pest in North American corn production. </p><p> The evolution of resistance is an ongoing concern, and to ensure Bt products will retain their usefulness, insect resistance management (IRM) tactics using various refuge structures have been adopted. One of the key tenets of the refuge strategy is that males and females emerging from Bt and refuge plantings mate randomly. A violation of this largely untested assumption would lead to acceleration of resistance development. </p><p> To generate empirical field data on mating rates between beetles emerging from Bt and refuge plants, field cage studies using field populations of WCR in Indiana were utilized. Various refuge configurations were tested; all refuge plants were labeled using the stable isotope N15. This mark persists in the adult beetles after eclosion, allowing for collection and analysis of isotopic ratios of beetles in mating pairs. This approach was used to test the random mating assumption in Bt and refuge beetles collected from field cages. Other data collected include emergence rates, timing and sex ratios for each of the treatments. </p><p> Results indicate that mating based on natal host may not be as important of a factor as initially thought. Mixed mating occurs at a high rate when there are higher numbers of susceptible rootworms even though the measured fitness parameters between <i>Cry3Bb1</i> and refuge adults were significantly different (p&lt; 0.05). The main indication from this study is that not enough susceptible individuals are produced from a 5% refuge-in-a-bag strategy which is the dominant form of refuge planting in the United States. </p>

Doctor of Philosophy / Department of Biology / Philip S. Gipson / Northern bobwhite (Colinus virginianus) populations in much of the species range have been declining for the last 35 years. I trapped and equipped bobwhite with radio transmitters and tracked them during 2003-2005. I used these data to examine the effects of landscape configuration on survival as well as the habitat association of bobwhite in southeastern Kansas. I used the nest survival model in Program MARK to determine the effects of habitat configuration on weekly survival of radio equipped bobwhite during the Fall-Spring (1 October to 14 April) and the Spring-Fall (15 April to 30 September) at home range and 500 m buffer scales. Individual survival probability for the Fall-Spring period was 0.9439 (S.E. = 0.0071), and the most parsimonious model for the Fall-Spring period at the home range scale was B0 + percent woodland + percent cropland. At the 500 m buffer scale the most parsimonious model was B0 + percent Conservation Reserve (CRP) program land. The weekly survival probability for the Spring-Fall period was 0.9559 (S.E. = 0.0098). At the home range and 500 m buffer scales there were weak associations of habitat to survival during Spring-Fall with the most parsimonious model for both scales B0 + percent other. Using Euclidean Distances to measure distance from animal location to each habitat, I found that habitat selection was occurring during the Spring-Fall (Wilkes λ = 0.04, F 6,36 = 143.682, P < 0.001) and Fall-Spring (Wilkes λ = 0.056, F 6, 29 = 81.99, P < 0.001). During Spring-Fall bobwhite were associated with locations near cool-season grasses and during Fall-Spring preferred locations near woody cover. Bobwhite also showed habitat selection at a second more refined land use classification level for Spring-Fall (Wilkes λ = 0.006, F 16, 26 = 284.483, P < 0.001) and Fall-Spring (Wilkes λ = 0.004, F 16, 19 = 276.037, P < 0.001). During the Spring-Fall, bobwhites were associated with locations near cool-season grass pastures and roads and during Fall-Spring were associated with locations in close proximity to roads and CRP. Understanding the effects of habitat configuration on bobwhite is an important step in developing a broad-scale management plan.

No description available.