Red-Cockaded Woodpecker Recovery: An Integrated Strategy

Populations of the red-cockaded woodpecker (Picoides borealis) have experienced massive declines since European colonization of North America. This is due to extensive habitat loss and alteration. Logging of old-growth pine forests and alteration of the fire regime throughout the historic range of the species were the primary causes of population decline. Listing of the red-cockaded woodpecker under the Endangered Species Act of 1973, as amended, and increased emphasis on management of non-game species have resulted in efforts to recover remnant populations of the red-cockaded woodpecker in many parts of its historic range. Due to extensive research and adaptive management initiatives much is now known about the elements required for both short- and long-term management of viable populations of red-cockaded woodpeckers. A short-term strategy is crucial because currently available habitat, in nearly all populations, is poor in 1 or more critical respects. Consequently, almost all populations require immediate attention in the short term, to insure suitable midstory and understory conditions, adequate availability of suitable cavities, and restoration of demographic viability through improvements in number and distribution of breeding groups. Management techniques including artificial cavities, cavity entrance restrictors, translocation of birds, prescribed fire, and mechanical and chemical control of woody vegetation are available to achieve these needs. In the long term, cost-effective management of red-cockaded woodpecker populations requires a timber management program and prescribed fire regime that will produce and maintain the stand structure characteristic of high quality nesting and foraging habitat, so that additional intensive management specific to the woodpeckers is no longer necessary. Timber management that achieves this goal and still allows substantial timber harvest is feasible. The implementation of a red-cockaded woodpecker management strategy, as outlined above, represents appropriate ecosystem management in the fire-maintained pine ecosystems of the southeastern United States and will ultimately benefit a great number of additional species of plants and animals adapted to this ecosystem

Exploring Agricultural Production Systems and Their Fundamental Components with System Dynamics Modelling

Agricultural production in the United States is undergoing marked changes due to rapid shifts in consumer demands, input costs, and concerns for food safety and environmental impact. Agricultural production systems are comprised of multidimensional components and drivers that interact in complex ways to influence production sustainability. In a mixed-methods approach, we combine qualitative and quantitative data to develop and simulate a system dynamics model that explores the systemic interaction of these drivers on the economic, environmental and social sustainability of agricultural production. We then use this model to evaluate the role of each driver in determining the differences in sustainability between three distinct production systems: crops only, livestock only, and an integrated crops and livestock system. The result from these modelling efforts found that the greatest potential for sustainability existed with the crops only production system. While this study presents a stand-alone contribution to sector knowledge and practice, it encourages future research in this sector that employs similar systems-based methods to enable more sustainable practices and policies within agricultural production

APPARENT SURVIVAL OF BREEDING WESTERN SANDPIPERS ON THE YUKON-KUSKOKWIM RIVER DELTA, ALASKA

We used 8 years of live recapture data (1998–2005) to estimate apparent annual survival for male (n = 237) and female (n = 296) Western Sandpipers (Calidris mauri) breeding on a 36-ha plot on the Yukon-Kuskokwim River Delta, western Alaska. Apparent annual survival (Φ) is the product of true survival and site fidelity, and estimates of Φ were corrected for the probability of encounter. Overall return rates (individual returned to the study site in a subsequent season) were lower for females (40%) than males (65%), as was Φ (± SE, females = 0.65 ± 0.05, males = 0.78 ± 0.03), and encounter rate (females = 0.51 ± 0.07, males = 0.74 ± 0.04). Results differed from previous estimates of Φ for this species as our estimates of Φ were higher for both males and females compared to estimates from another breeding site and two nonbreeding locations. Disparity among Φ estimates from breeding and nonbreeding areas highlights the need to delineate site-specific factors throughout the annual cycle that influence population dynamics of the Western Sandpiper

APPARENT SURVIVAL OF BREEDING WESTERN SANDPIPERS ON THE YUKON-KUSKOKWIM RIVER DELTA, ALASKA

We used 8 years of live recapture data (1998–2005) to estimate apparent annual survival for male (n = 237) and female (n = 296) Western Sandpipers (Calidris mauri) breeding on a 36-ha plot on the Yukon-Kuskokwim River Delta, western Alaska. Apparent annual survival (Φ) is the product of true survival and site fidelity, and estimates of Φ were corrected for the probability of encounter. Overall return rates (individual returned to the study site in a subsequent season) were lower for females (40%) than males (65%), as was Φ (± SE, females = 0.65 ± 0.05, males = 0.78 ± 0.03), and encounter rate (females = 0.51 ± 0.07, males = 0.74 ± 0.04). Results differed from previous estimates of Φ for this species as our estimates of Φ were higher for both males and females compared to estimates from another breeding site and two nonbreeding locations. Disparity among Φ estimates from breeding and nonbreeding areas highlights the need to delineate site-specific factors throughout the annual cycle that influence population dynamics of the Western Sandpiper

Population changes in Leishmania chagasi promastigote developmental stages due to serial passage

Leishmania chagasi causes visceral leishmaniasis, a potentially fatal disease of humans. Within the sand fly vector, L. chagasi replicates as promastigotes which undergo complex changes in morphology as they progress from early stage procyclic promastigotes, to intermediate stage leptomonad and nectomonad promastigotes, and ultimately to terminal stage metacyclic promastigotes that are highly infective to vertebrates. This developmental progression is largely recapitulated in vitro using axenic promastigote cultures that have been passaged only a few times. Within a single passage (which takes about a week), axenic cultures progress from logarithmic to stationary growth phases; parasites within those growth phases progress from stages that do not have metacyclic cell properties to ones that do. Interestingly, repeated serial passage of promastigote cultures will result in cell populations that exhibit perturbations in developmental progression, in expression levels of surface macromolecules (major surface protease, MSP, and promastigote surface antigen, PSA), and in virulence properties, including resistance to serum lysis. Experiments were performed to determine whether there exists a direct relationship between promastigote developmental form and perturbations associated with repeated serial passage. Passage 2 to passage 4 L. chagasi cultures at stationary growth phase were predominately (\u3e85%) comprised of metacyclic promastigotes and exhibited high resistance to serum lysis and high levels of MSP and PSA. Serial passaging 8, or more, times resulted in a stationary phase population that was largely (\u3e85%) comprised of nectomonad promastigotes, almost completely devoid (\u3c2%) of metacyclic promastigotes, and that exhibited low resistance to serum lysis and low levels of MSP and PSA. The study suggests that the loss of particular cell properties seen in cells from serially passaged cultures is principally due to a dramatic reduction in the proportion of metacyclic promastigotes. Additionally, the study suggests that serially passaged cultures may be a highly enriched source of nectomonad-stage promastigotes, a stage that has largely been characterized only in mixtures containing other promastigote forms

An experimental study of the impact of location on the effectiveness of recruitment clusters for Red-cockaded Woodpeckers at the Savannah River Site.

An experimental study of the impact of location on the effectiveness of recruitment clusters for Red-Cockaded Woodpeckers at the Savannah River Site

Quantifying Low Energy Proton Damage in Multijunction Solar Cells

An analysis of the effects of low energy proton irradiation on the electrical performance of triple junction (3J) InGaP2/GaAs/Ge solar cells is presented. The Monte Carlo ion transport code (SRIM) is used to simulate the damage profile induced in a 3J solar cell under the conditions of typical ground testing and that of the space environment. The results are used to present a quantitative analysis of the defect, and hence damage, distribution induced in the cell active region by the different radiation conditions. The modelling results show that, in the space environment, the solar cell will experience a uniform damage distribution through the active region of the cell. Through an application of the displacement damage dose analysis methodology, the implications of this result on mission performance predictions are investigated