Lessons learned: tidal marsh restoration in a dynamic context of stress and climate change

In the Stillaguamish estuary, tidal wetlands have been receding for decades as a result of both natural and anthropogenic changes. Despite current restoration efforts, monitoring suggests that rising stress from climate change impacts on summer flows, legacy stresses from the levee system, and increased plant mortality from avian and insect herbivores may interact to accelerate the rate of marsh loss. Lessons learned from a 2012 restoration project should inform adaptive management and future restoration projects. Post-restoration monitoring has revealed a pattern of interacting stresses at both the site and system scales that affects marsh productivity and resilience to climate change. These stresses are spatially and temporally variable. Different marsh areas respond differently, revealing characteristics of marshes that are vulnerable, resilient, or able to resist disturbance. At current restoration rates, marsh loss may slow temporarily, but not reverse. To accelerate estuary recovery, restoration must focus on reducing system-scale stresses by restoring the processes of freshwater and sediment distribution. At the site-scale, projects should identify pre-restoration conditions that may contribute to elevated plant stress post-restoration, including topography, drainage, and soil profile characteristics

Pathophysiology and recovery of myotis lucifugus affected by white nose syndrome

Critical to our understanding of wildlife diseases is the recovery phase, a period during which individuals clear infections and return to normal patterns of behavior and physiology. Most research on effects of white nose syndrome (WNS), an emerging fungal disease in bats, has focused on the pathophysiology of winter mortality and the effects of WNS on hibernating populations. The period immediately following emergence from hibernation has received little attention, but is a critically important time for survivors of the disease. During this time, survivors face significant physical and physiological challenges as they migrate to summer habitats, potentially begin gestation in the case of reproductive females, and begin to recover from wing damage caused by the fungus, which can be extensive and may greatly increase the energetic cost of flight. In this study, I (1) test the hypothesis that free-ranging bats heal from WNS-induced wing damage, (2) determine how WNS-induced wing damage changes skin surface lipid profiles on free-ranging bats, and (3) describe the temporal process of disease recovery in a colony of captive bats, including analyses of body mass, wing damage, pathogen load, skin surface lipid profiles, and histopathological metrics of WNS. I find that bats can quickly heal from wing damage in the wild and appear healthy as early as mid-July in New England. Analysis of skin surface lipids does not reveal any striking differences between bats with wing damage and those without, although there are trends towards lower total surface lipids and increased levels of cutaneous cholesterol in bats with severe wing damage. Finally, I show that within 40 days of emerging from hibernation, bats quickly clear the fungal infection and gain body mass, undergoing rapid healing of wing damage and changes in skin surface lipid composition. Bats depend on their wings for a variety of vital processes including physiological regulation, locomotion and feeding. To fully understand the consequences of WNS and develop actionable management strategies, it is important to consider the long-term effects of this disease. My study helps fill critical knowledge gaps and will aid in the future conservation and management of affected bat species

Coastal Resilience for Habitats and Humans: Integrating Green and Grey Infrastructure Solutions

Communities are protected from floods and storms by both engineered infrastructure like levees, and natural habitat infrastructure like wetlands. We understand the performance and cost effectiveness of engineered or grey infrastructure well. However, recent natural disasters have illustrated both their insufficiency in protecting communities and the high repair costs. We know that green infrastructure, or natural habitats, also protect communities from river floods and coastal storms but we know little about their performance and cost. This knowledge gap leads to greater investment in grey at the expense of green. In addition, green infrastructure provide other benefits to human communities, and are often the restoration target of recovery plans for ecosystems and endangered species. In Puget Sound we evaluated the changes in vulnerability for both ecosystems and built infrastructure that may result from climate change, including changes in high and low river flows, sea level, storm dynamics, sediment recruitment and salinity intrusion. We developed an interactive tool called Coastal Resilience that allows users to examine community risk in a way that integrates both green and grey infrastructure. The tool allows users to evaluate different sources of risk, such as “dike freeboard” which indicates how close a dike comes to being overtopped under various current and future storm scenarios. Another tool provides a model that quantifies the reduction in storm wave energy and height that is provided by tidal wetlands which protect adjacent dike systems from erosion and overtopping. In areas where tidal wetlands are receding, it can indicate how community risk and financial cost may change as a result of this loss of protective green infrastructure. With this information, communities can develop better response plans that reduce the costs of disaster prevention and recovery, and increase the economic efficiency of both risk reduction and ecosystem recovery actions

Perception and steering control in paired bat flight

Animals within groups need to coordinate their reactions to perceived environmental features and to each other in order to safely move from one point to another. This paper extends our previously published work on the flight patterns of Myotis velifer that have been observed in a habitat near Johnson City, Texas. Each evening, these bats emerge from a cave in sequences of small groups that typically contain no more than three or four individuals, and they thus provide ideal subjects for studying leader-follower behaviors. By analyzing the flight paths of a group of M. velifer, the data show that the flight behavior of a follower bat is influenced by the flight behavior of a leader bat in a way that is not well explained by existing pursuit laws, such as classical pursuit, constant bearing and motion camouflage. Thus we propose an alternative steering law based on virtual loom, a concept we introduce to capture the geometrical configuration of the leader-follower pair. It is shown that this law may be integrated with our previously proposed vision-enabled steering laws to synthesize trajectories, the statistics of which fit with those of the bats in our data set. The results suggest that bats use perceived information of both the environment and their neighbors for navigation.2018-08-0

Perceptual modalities guiding bat flight in a native habitat

Flying animals accomplish high-speed navigation through fields of obstacles using a suite of sensory modalities that blend spatial memory with input from vision, tactile sensing, and, in the case of most bats and some other animals, echolocation. Although a good deal of previous research has been focused on the role of individual modes of sensing in animal locomotion, our understanding of sensory integration and the interplay among modalities is still meager. To understand how bats integrate sensory input from echolocation, vision, and spatial memory, we conducted an experiment in which bats flying in their natural habitat were challenged over the course of several evening emergences with a novel obstacle placed in their flight path. Our analysis of reconstructed flight data suggests that vision, echolocation, and spatial memory together with the possible exercise of an ability in using predictive navigation are mutually reinforcing aspects of a composite perceptual system that guides flight. Together with the recent development in robotics, our paper points to the possible interpretation that while each stream of sensory information plays an important role in bat navigation, it is the emergent effects of combining modalities that enable bats to fly through complex spaces

Optical flow sensing and the inverse perception problem for flying bats

The movements of birds, bats, and other flying species are governed by complex sensorimotor systems that allow the animals to react to stationary environmental features as well as to wind disturbances, other animals in nearby airspace, and a wide variety of unexpected challenges. The paper and talk will describe research that analyzes the three-dimensional trajectories of bats flying in a habitat in Texas. The trajectories are computed with stereoscopic methods using data from synchronous thermal videos that were recorded with high temporal and spatial resolution from three viewpoints. Following our previously reported work, we examine the possibility that bat trajectories in this habitat are governed by optical flow sensing that interpolates periodic distance measurements from echolocation. Using an idealized geometry of bat eyes, we introduce the concept of time-to-transit, and recall some research that suggests that this quantity is computed by the animals' visual cortex. Several steering control laws based on time-to-transit are proposed for an idealized flight model, and it is shown that these can be used to replicate the observed flight of what we identify as typical bats. Although the vision-based motion control laws we propose and the protocols for switching between them are quite simple, some of the trajectories that have been synthesized are qualitatively bat-like. Examination of the control protocols that generate these trajectories suggests that bat motions are governed both by their reactions to a subset of key feature points as well by their memories of where these feature points are located

Tackle-related injury rates and nature of injuries in South African Youth Week tournament rugby union players (under-13 to under-18): an observational cohort study.

OBJECTIVES: The tackle situation is most often associated with the high injury rates in rugby union. Tackle injury epidemiology in rugby union has previously been focused on senior cohorts but less is known about younger cohorts. The aim of this study was to report on the nature and rates of tackle-related injuries in South African youth rugby union players representing their provinces at national tournaments. DESIGN: Observational cohort study. SETTING: Four South African Youth Week tournaments (under-13 Craven Week, under-16 Grant Khomo Week, under-18 Academy Week, under-18 Craven Week). PARTICIPANTS: Injury data were collected from 3652 youth rugby union players (population at risk) in 2011 and 2012. OUTCOME MEASURES: Tackle-related injury severity ('time-loss' and 'medical attention'), type and location, injury rate per 1000 h (including 95% CIs). Injury rate ratios (IRR) were calculated and modelled using a Poisson regression. A χ(2) analysis was used to detect linear trends between injuries and increasing match quarters. RESULTS: The 2012 under-13 Craven Week had a significantly greater 'time-loss' injury rate when compared with the 2012 under-18 Academy Week (IRR=4.43; 95% CI 2.13 to 9.21, p<0.05) and under-18 Craven Week (IRR=3.52; 95% CI 1.54 to 8.00, p<0.05). The Poisson regression also revealed a higher probability of 'overall' ('time-loss' and 'medical attention' combined) and 'time-loss' tackle-related injuries occurring at the under-13 Craven Week. The proportion of 'overall' and 'time-loss' injuries increased significantly with each quarter of the match when all four tournaments were combined (p<0.05). CONCLUSIONS: There was a difference in the tackle-related injury rate between the under-13 tournament and the two under-18 tournaments, and the tackle-related injury rate was higher in the final quarter of matches. Ongoing injury surveillance is required to better interpret these findings. Injury prevention strategies targeting the tackle may only be effective once the rate and nature of injuries have been accurately determined

NEPC Review: Evaluation of Teach for America in Texas Schools

A new study funded by Teach for America (TFA) attempts to identify the effect of TFA teachers and alumni on student test scores. The report, by Edvance Research, matched schools and students within those schools on both demographic and achievement characteristics. It then used the matched student data in a multi-level regression analysis to estimate the effect of being taught by a TFA teacher on mathematics and reading test scores for two groups of students: those in grades 4 and 5 and those in grades 6 through 8. Of the eight comparisons performed, three were statistically significant: mathematics and reading scores of middle-level students taught by TFA alumni and mathematics scores for middle-level students taught by novice TFA teachers. While the findings were large enough to be relevant to policymakers, numerous issues with the sample construction, matching procedures, and statistical analyses lead us to conclude the outcomes cannot be attributed to TFA teachers. Furthermore, these issues make it likely that the actual size of the TFA teacher effects differ than what is found in the report. Thus, the report should not be accepted as solid evidence of any TFA teacher or TFA alumni effect.</p

Evidence in support of the call to ban the tackle and harmful contact in school rugby: a response to World Rugby

In a paper published in BJSM (June 2016), World Rugby employees Ross Tucker and Martin Raftery and a third coauthor Evert Verhagen took issue with the recent call to ban tackling in school rugby in the UK and Ireland. That call (to ban tackling) was supported by a systematic review published in BJSM. Tucker et al claim that: (1) the mechanisms and risk factors for injury along with the incidence and severity of injury in youth rugby union have not been thoroughly identified or understood; (2) rugby players are at no greater risk of injury than other sports people, (3) this is particularly the case for children under 15 years and (4) removing the opportunity to learn the tackle from school pupils might increase rates of injuries. They conclude that a ban ‘may be unnecessary and may also lead to unintended consequences such as an increase in the risk of injury later in participation.’ Here we aim to rebut the case by Tucker et al. We share new research that extends the findings of our original systematic review and meta-analysis. A cautionary approach requires the removal of the tackle from school rugby as the quickest and most effective method of reducing high injury rates in youth rugby, a public health priority