A test of the mismatch hypothesis: How is timing of reproduction related to food abundance in an aerial insectivore?

In seasonal environments, vertebrates are generally thought to time their reproduction so offspring are raised during the peak of food abundance. The mismatch hypothesis predicts that reproductive success is maximized when animals synchronize their reproduction with the food supply. Understanding the mechanisms influencing the timing of reproduction has taken on new urgency as climate change is altering environmental conditions during reproduction, and there is concern that species will not be able to synchronize their reproduction with changing food supplies. Using data from five sites over 24 years (37 site-years), we tested the assumptions of the mismatch hypothesis in the Tree Swallow (Tachycineta bicolor), a widespread aerial insectivore, whose timing of egg-laying has shifted earlier by nine days since the 1950s. Contrary to the mismatch hypothesis, the start of egg-laying was strongly related to food abundance (flying insect biomass) during the laying period and not to timing of the seasonal peak in food supply. In fact, food abundance generally continued to increase throughout the breeding season, and there was no evidence of selection based on the mistiming of laying with the seasonal peak of food abundance. In contrast, there was selection for laying earlier, because birds that lay earlier generally have larger clutches and fledge more young. Overall, initial reproductive decisions in this insectivore appear to be based on the food supply during egg formation and not the nestling period. Thus, the mismatch hypothesis may not apply in environments with relatively constant or abundant food throughout the breeding season. Although climate change is often associated with earlier reproduction, our results caution that it is not necessarily driven by selection for synchronized reproduction.     

The unrecognized danger of a new transportation mechanism of injury--pedicabs

Objective

Pedicabs are a new and controversial transportation innovation for tourists in congested areas in several U.S. cities. Scant literature on this trauma mechanism exists. The purpose of this study is to identify the incidence, demographics, morbidity, mortality, and potential for injury prevention of pedicab incidents amongst major trauma admissions at an urban, academic Level I Trauma Center.

Patients & Methods

Researchers conducted a retrospective review of the Trauma Registry from 2000 to 2009. All patients identified as being injured in a pedicab incident were reviewed. Demographics, diagnoses, toxicology, treatments, and injury severity scale (ISS) were collected. Outcomes included mortality, ICU, and hospital length of stay (LOS), discharge disposition, and hospital charges. A photographic survey of 50 local pedicabs was examined for the presence and use of safety equipment.

Results

During the period of January 2000 to July 2009 there were 15 major trauma victims from identified pedicab incidents. Falling from the pedicab was the mechanism of injury in 14 of 15 cases. There were two fatalities in victims following severe traumatic brain injury. Traumatic brain injury, skull fracture, or loss of consciousness was seen in 11/15 victims. Ethanol ingestion was detected in blood tests of 10 of the 14 adult victims. Median charges of hospitalization due to a pedicab related injury was US$29,956 ± 77,482. A photographic survey of 50 local pedicabs reveals very limited use of safety belts by passengers despite existing city ordinances.

Conclusions

Major trauma victims of pedicab incidents in the United States suffer significant injuries and death. Most cases occurred in passengers falling from the pedicab at night after alcohol ingestion. There is an opportunity for implementation of strategies toward improved injury prevention with this new form of transport.     

Locating Existing Best Management Practices Within a Watershed: The Value of Multiple Methods

There is an increasing need to document the impacts of conservation‐related best management practices (BMPs) on water quality within a watershed. However, this impact analysis depends upon accurate geospatial locations of existing practices, which are difficult to obtain. This study demonstrates and evaluates three different methods for obtaining geospatial information for BMPs. This study was focused on the Eagle Creek Watershed, a mixed use watershed in central Indiana. We obtained geospatial information for BMPs through government records, producer interviews, and remote‐sensing aerial photo interpretation. Aerial photos were also used to validate the government records and producer interviews. This study shows the variation in results obtained from the three sources of information as well as the benefits and drawbacks of each method. Using only one method for obtaining BMP information can be incomplete, and this study demonstrates how multiple methods can be used for the most accurate picture.     

Beyond water data: benefits to volunteers and to local water from a citizen science program

Survey results of citizen science water data collection volunteers are presented, indicating personal benefits (e.g., being in nature, helping local water quality), and suggesting potential long-term benefits of improved watershed health (e.g., behavior change). These results can inform citizen science program development and contribute to watershed planners’ understanding of the broad benefits of such programs. We suggest that respondents’ positive feelings toward the watershed's major river and desire to learn about science and nature are place-specific elements that watershed and citizen science program managers could utilize in program development. Moreover, we explore the potential of social diffusion and behavior change and suggest the need for further research in these areas. We conclude that citizen science has potential not just as a means to collect large amounts of data (cheaply), but as a means to engage citizens to make environmentally friendly decisions.     

The influence of field-scale heterogeneity on the infiltration and entrapment of dense nonaqueous phase liquids in saturated formations

Numerical simulations are used for the systematic exploration of the migration and entrapment of dense nonaqueous phase liquids (DNAPLs) in heterogeneous formations. Ensembles of realizations of random, spatially correlated permeability fields are generated and employed in model simulations of a spill event. Statistical techniques are then used to quantify the sensitivity of model predictions to input parameters, thereby identifying the parameters or processes that may be of primary importance in the determination of organic liquid distributions in heterogeneous systems. Results of the study indicate that the most critical factors in modeling organic entrapment include the spill release rate, reliable estimates of the mean, variance, and vertical correlation scale of the formation permeability, and an accurate representation of the correlation between the capillary pressure–saturation function and the permeability. In contrast, the hydraulic gradient and cross-correlation of residual saturations with permeabilities are found to have only minor influence on organic liquid distributions in such heterogeneous formations.     

Importance of conserving large and old trees to continuity of tree-related microhabitats

Protecting structural features, such as tree-related microhabitats (TreMs), is a cost-effective tool crucial for biodiversity conservation applicable to large forested landscapes. Although the development of TreMs is influenced by tree diameter, species, and vitality, the relationships between tree age and TreM profile remain poorly understood. Using a tree-ring-based approach and a large data set of 8038 trees, we modeled the effects of tree age, diameter, and site characteristics on TreM richness and occurrence across some of the most intact primary temperate forests in Europe, including mixed beech and spruce forests. We observed an overall increase in TreM richness on old and large trees in both forest types. The occurrence of specific TreM groups was variably related to tree age and diameter, but some TreM groups (e.g., epiphytes) had a stronger positive relationship with tree species and elevation. Although many TreM groups were positively associated with tree age and diameter, only two TreM groups in spruce stands reacted exclusively to tree age (insect galleries and exposed sapwood) without responding to diameter. Thus, the retention of trees for conservation purposes based on tree diameter appears to be a generally feasible approach with a rather low risk of underrepresentation of TreMs. Because greater tree age and diameter positively affected TreM development, placing a greater emphasis on conserving large trees and allowing them to reach older ages, for example, through the establishment of conservation reserves, would better maintain the continuity of TreM resource and associated biodiversity. However, this approach may be difficult due to the widespread intensification of forest management and global climate change.     

The efficiency of using non-culpable crash-claim involvements from insurance data as a means of estimating travel exposure for road user sub-groups

Introduction

Induced exposure has a long history of development and usage in traffic safety research but a major question has always concerned the extent to which the accumulation of culpable and non-culpable involvements can be considered independent.

Method

Culpability assessments of 32,630 vehicles' crash-claim involvements adjudicated by insurance adjusters were matched with vehicle odometer readings taken at emission testing using consistent identification of vehicles and principal operators over a 5-year period.

Result

It was found that the accumulation of culpable crash involvements was not entirely independent of that for non-culpable involvements. However, the rate of non-culpable involvements was determined to be an acceptable surrogate for travel exposure rate where sample sizes were large.

Discussion

The relationship between the rate of non-culpable involvements and the rate of travel exposure for data subsets when both were normalized by the overall sample rates was reminiscent of an accident-volume curve for roadway locations in traffic engineering theory. This suggested that only a portion of non-culpable involvements actually related directly to travel and this lead to a correction factor that could be applied.

Impact on Industry

While lack of independence of involvement rates may be problematic for a direct risk ratio application, it does not invalidate the use of non-culpable involvements to predict travel. For insurers that have a need to estimate travel amounts for different driver/vehicle groups as part of the insurance rating purposes, this can be a useful application.     

Work values: Development of a new three-dimensional structure based on confirmatory smallest space analysis

We tested the psychological structure of the work values ratings of 119,167 Canadian workers using confirmatory smallest space analysis (SSA). Contrary to our hypotheses, the SSA did not support a two-dimensional radex structure, but suggested a three-dimensional cylindrex structure composed of three facets: (a) A modality facet comprised of four types of work values (cognitive, instrumental, social, and prestige) forming angular sectors of a circle; (b) a growth-orientation facet with growth-related work aspects located closest to the center of the circle and context-related work aspects located in the peripheral ring; and (c) a level of focus facet that divided the overall cylindrical structure into three separate vertical levels (individual, job/organizational, and societal). The findings extend the theory of work values by providing a richer typology of work values and a more complete picture of the complex structure of their inter-relations. Copyright © 2009 John Wiley & Sons, Ltd.     

Land use change effects on forest carbon cycling throughout the southern United States

We modeled the effects of afforestation and deforestation on carbon cycling in forest floor and soil from 1900 to 2050 throughout 13 states in the southern United States. The model uses historical data on gross (two-way) transitions between forest, pasture, plowed agriculture, and urban lands along with equations describing changes in carbon over many decades for each type of land use change. Use of gross rather than net land use transition data is important because afforestation causes a gradual gain in carbon stocks for many decades, while deforestation causes a much more rapid loss in carbon stocks. In the South-Central region (Texas to Kentucky) land use changes caused a net emission of carbon before the 1980s, followed by a net sequestration of carbon subsequently. In the Southeast region (Florida to Virginia), there was net emission of carbon until the 1940s, again followed by net sequestration of carbon. These results could improve greenhouse gas inventories produced to meet reporting requirements under the United Nations Framework Convention on Climate Change. Specifically, from 1990 to 2004 for the entire 13-state study area, afforestation caused sequestration of 88 Tg C, and deforestation caused emission of 49 Tg C. However, the net effect of land use change on carbon stocks in soil and forest floor from 1990 to 2004 was about sixfold smaller than the net change in carbon stocks in trees on all forestland. Thus land use change effects and forest carbon cycling during this period are dominated by changes in tree carbon stocks.