The behavioral response of emerging pine snakes (<Emphasis Type="Italic">Pituophis melanoleucus</Emphasis>) to people: implications for survival and protection

Considerable attention has been devoted to the effects of people on birds and mammals, usually in wilderness areas. In contrast, human disturbance of reptiles has largely been ignored. Many reptiles, such as snakes, are hard to conserve because they are difficult to locate and protect. The young are especially vulnerable to predators when they first hatch and must emerge from nest sites. In this paper, the response of pine snake (Pituophis melanoleucus) hatchlings to the presence and handling by people was observed in the laboratory and in the field. Pine snakes lay their eggs in underground burrows in open sandy pine barrens, and the hatchlings push their way to the surface to emerge. Hatchlings that were visually-disturbed or touched as they emerged returned immediately to their tunnels and nests, and required more time to re-emerge than did their siblings that were not visually-disturbed or touched during their initial disturbance. In nature, undisturbed pine snakes showed similar re-emergence times to those from the laboratory, and disturbed snakes required longer to re-emerge. These data suggest that in nature even the presence of people in nesting areas of pine snakes would lengthen the time the young are in burrows, exposing them to additional threats from predators. This suggests that parks or nature reserves with vulnerable snake populations should restrict human disturbance during the period when young snakes are emerging from their nests. Field observations indicate that a set-back distance of more than 12 m from known nesting areas is essential to protect emerging hatchlings.     

Effects of off-road vehicles on reproductive success of pine snakes (<Emphasis Type="Italic">Pituophus melanoleucus</Emphasis>) in the New Jersey pinelands

Considerable attention has been devoted to the effects of people and their vehicles on birds and mammals, but possible effects on reptiles in populated areas have received less attention. Moreover, the effects of human activities on reptile reproductive success itself has been harder to demonstrate. This paper examines the effect of management of off-road vehicles in New Jersey’s pinelands on the reproductive success of pine snakes (Pituophus melanoleucus) from 1986 to 2005. We used the percentage of snakes in each hibernaculum that were young of the year (hatchlings) as an indicator of reproductive success, and compared this percent for five hibernacula that were in an area with varying degrees of off-road vehicle (ORV) disturbance, with 12 hibernacula in areas with no ORV disturbances (reference sites). This percent took into account differences in absolute numbers from one location to another, and over time due to hibernacula destruction (by people or predators) and natural variations (food supply). The ORV pressure in the pinelands is intense because it lies within the most densely populated urban area in the United States. Although the number of snakes in the reference hibernacula varied over the years from 46 to 63, the percent of young in these hibernacula did not vary significantly over the 20 year period (21–29%). In contrast, the percent-young in the disturbed sites differed significantly in years without ORV disturbance (28%) compared to those with ORV disturbance (15 and 16%, P < 0.01). Further, there were no differences between the percent of young in the reference sites and those in the disturbed site in years without ORV disturbance. ORV disturbance ceased only with the creation of large dirt berms coupled with fences that could not be easily broken. These data indicate the importance of having detailed population data on pine snakes in hibernacula, on ORV use (or indications of such use), and of managing ORV use to protect sensitive populations. Maintenance of healthy pine snake populations in urban areas may require continued adaptive management.     

Developing Employment Opportunities for Care Leavers

This article describes an action research project carried out in North West England that aimed to assist Children’s Services Departments and Care Trusts in developing their strategies for supporting care leavers into employment and training. The study found a range of models and approaches that can be utilised to develop local and regional partnerships offering employment and training opportunities designed to meet the needs of care leavers. Relevant questions about the extent to which such opportunities should be ring‐fenced or targeted on particular fields of employment are identified. © 2010 The Author(s). Children & Society © 2010 National Children’s Bureau.     

Three-factor symmetrical balanced designs with full efficiency for main effects

Some methods for constructing balanced design for 3-factor symmetrical factorial experiments in which all the main effects are completely unconfounded by using balanced arrays and BIB designs are proposed. The method is flexible in terms of selecting block size.     

Uncovering Alternate Ethnic Identity Trajectories: A Cluster Analysis of the MEIM and Psychological Well-Being

Race and Social Problems - There is vast support in the racial-ethnic identity literature that there is a positive association between racial-ethnic identity and psychological well-being. The...     

AN APPROACH FOR JOINTLY MODELING MULTIVARIATE LONGITUDINAL MEASUREMENTS AND DISCRETE TIME-TO-EVENT DATA

In many medical studies, patients are followed longitudinally and interest is on assessing the relationship between longitudinal measurements and time to an event. Recently, various authors have proposed joint modeling approaches for longitudinal and time-to-event data for a single longitudinal variable. These joint modeling approaches become intractable with even a few longitudinal variables. In this paper we propose a regression calibration approach for jointly modeling multiple longitudinal measurements and discrete time-to-event data. Ideally, a two-stage modeling approach could be applied in which the multiple longitudinal measurements are modeled in the first stage and the longitudinal model is related to the time-to-event data in the second stage. Biased parameter estimation due to informative dropout makes this direct two-stage modeling approach problematic. We propose a regression calibration approach which appropriately accounts for informative dropout. We approximate the conditional distribution of the multiple longitudinal measurements given the event time by modeling all pairwise combinations of the longitudinal measurements using a bivariate linear mixed model which conditions on the event time. Complete data are then simulated based on estimates from these pairwise conditional models, and regression calibration is used to estimate the relationship between longitudinal data and time-to-event data using the complete data. We show that this approach performs well in estimating the relationship between multivariate longitudinal measurements and the time-to-event data and in estimating the parameters of the multiple longitudinal process subject to informative dropout. We illustrate this methodology with simulations and with an analysis of primary biliary cirrhosis (PBC) data.     

Trapped in migrants’ sectors? Polish women in the Icelandic labour market

The employment‐driven migrations from Poland to Iceland have largely been pioneered by Polish women. They outnumbered men among Polish residents in this country until the economic boom since 2005 triggered large‐scale male immigration. This trend slowed down with the outbreak of the financial crisis, as the recession severely affected the male‐dominated construction industry. The analysis of Polish female migrants’ working experiences shows that recent inflows are mainly shaped by the nature of labour demand as well as the social policies and care services in Iceland. Although economically integrated, compared with native women Polish women tend to occupy rather disadvantaged positions. They seem concentrated in a few low‐skilled occupations that bring little prestige and low income. On the other hand, they were less affected by the financial crisis, in the sense that many of them maintained work, though some experienced lowering of salaries or reduction of working hours.     

Basking habitat use and response of freshwater turtles to human presence in an urban canal of Central New Jersey

Pressures of rapid development continue to increase, and recreational activities are becoming a prominent driving force in many urban wildlife communities. Freshwater turtles live in many urban environments, yet little attention has been given to the impact of human recreation upon these communities. We examined the response of basking turtles to observer presence along the towpath of a recreational canal in central New Jersey. All species, except for turtles of the family Kinosternidae, were more frequently observed basking on substrate with less than 50 % canopy cover, log substrate was most preferred, and turtles on the towpath side basked an average of 3 m from the towpath. Turtles were vigilant and over 75 % of C. picta, T.S. elegans, and P. rubriventris responded to observer presence by retreating (swimming away). The distance from the towpath turtles were first seen basking by the observer (approach distance) was significantly correlated with the flight-initiation distance (distance of first respond to observer). Nearly 80 % of the variability in flight initiation distance for Kinosternidae was accounted for by the percent canopy cover, percent cloud cover, and height basking above the water. Researchers aiming to quantify and manage human recreational impact on turtles should examine flight-initiation distances. We encourage wildlife managers of urban parks to construct towpaths or recreational areas at a minimum of 7 m from the water’s edge, maintain moderate vegetation in basking areas, and construct additional basking platforms opposite from towpaths or at great distances from human recreational areas.