Response of small mammal mycophagy to varying levels and patterns of green-tree retention in mature forests of western Oregon and Washington

The Demonstration of Ecosystem Management Options (DEMO) study is a large-scale, multi-year, interdisciplinary project examining the effects of various levels and patterns of green-tree retention on multiple forest features. Six retention levels and patterns were examined and replicated across six blocks of predominately Douglas-fir forested land in western Oregon and Washington. As part of the DEMO study, this research focuses on the effects of these silviculture activities on small mammal mycophagy. The diets of three small mammal groups were examined: squirrels (the northern flying squirrel, Glaucomys sabrinus), chipmunks (Townsend's chipmunk - Tarnias townsendii, and the Siskiyou chipmunk - T. siskiyou), and voles (the western and southern red-backed voles - Clethrionomys calfornicus and C. gapperi). These animals are vital fungal spore dispersers and forest prey. Fecal pellet analysis was used as a non-lethal method of examining the diets of these mycophagous mammals. Fecal samples were collected from these animals before and after the application of treatments. Pretreatment diet data was utilized for a diet comparison among the animal genera. The change in the frequencies for the common truffle genera, plant material, and total cumulative number of genera were compared using an analysis of variance to measure the effect of each treatment on the diets of the study animals. The pre-treatment fungal diets of the study animals showed significant differences among genera. Glaucomys sabrinus fecal samples contained higher frequencies of Gautieria and Leucogaster spores than either Clethrionornys or Tamias samples. The diet of the Tamias spp. contained higher frequencies of plant material than G. sabrinus or Clethrionomys, emphasizing the more diverse diet of this animal genus. G. sabrinus samples contained the highest mean number of truffle genera per sample and consistently contained a high frequency of the four common truffle genera. Moderately high frequencies of the common truffle genera were conimon in the Clethrionomys samples. Only the genus Rhizopogon was commonly found in high frequencies in the Tamias samples. The frequency of Rhizopogon spores was consistently greater than 95% in the pre-treatment diets of all animal genera. Treatment effects were found for different diet items for each animal genus. The mean total cumulative number of truffle genera in the diet of the study animals showed little change. The harvesting of trees appears to negatively affect the frequency of Rhizopogon spores in the diet of Clethrionomys, potentially reflecting the reduced ability of these animals to forage for Rhizopogon truffles and a reduction in Rhizopogon truffle abundance or frequency, especially in the 15% aggregated retention treatment. The retention of trees in isolated aggregates restricts the movement of Clethrionomys within the treatment and the abundance of edge on the aggregates may further restrict Clethrionornys to the center of the aggregates. Competition would be increased within these aggregates where animals are concentrated and the resource may be even more limited. In the diet of G. sabrinus, the frequency of Gautieria spores significantly decreased in the 40% aggregated retention treatment and increased in the 40% dispersed retention treatment. The retention of trees in aggregates may limit the ability of G. sabrinus to move and forage between aggregates and into adjacent habitat. However, in the dispersed retention treatments, adequate travel routes are still available and G. sabrinus could forage throughout the treatment and in to adjacent habitat, thus reducing the impact of the reduction of truffle biomass within a stand. The diet of the Tamias spp. showed little change in response to the treatments. The wide diversity of habitats that Tamias utilize may extend the ability of this animal to find and compete for truffles even as they decreased locally, until a large decrease in biomass occurred. The sporocarp biomass data (D. Luoma, unpublished data) showed that overall truffle biomass declined, whereas consumption of truffles by these small mammals largely stayed the same. This suggests that the animals are compensating for a locally declining food source by altering their foraging behavior. The long term effects of this behavioral compensation on energetic s and population dynamics is unknown

Effects of prior experience on shelter-seeking behavior of juvenile American lobsters

Author Posting. © University of Chicago, 2017. This article is posted here by permission of University of Chicago for personal use, not for redistribution. The definitive version was published in Biological Bulletin 232 (2017): 101-109, doi:10.1086/692697.Shelter-seeking behaviors are vital for survival for a range of juvenile benthic organisms. These behaviors may be innate or they may be affected by prior experience. After hatching, American lobsters Homarus americanus likely first come into contact with shelter during the late postlarval (decapodid) stage, known as stage IV. After the subsequent molt to the first juvenile stage (stage V), they are entirely benthic and are thought to be highly cryptic. We hypothesized that postlarval (stage IV) experience with shelter would carry over into the first juvenile stage (stage V) and reduce the time needed for juveniles to locate and enter shelters (sheltering). We found some evidence of a carryover effect, but not the one we predicted: stage V juveniles with postlarval shelter experience took significantly longer to initiate sheltering. We also hypothesized that stage V juveniles would demonstrate learning by relocating shelters more quickly with immediate prior experience. Our findings were mixed. In a maze, juveniles with immediate prior experience were faster to regain visual contact with shelter, suggesting that they had learned the location of the shelter. In contrast, there was no significant effect of immediate prior experience on time to initiate sheltering in an open arena, or in the maze after juveniles had regained visual contact. We conclude that very young (stage V) juvenile lobsters modify their shelter-seeking behavior based on prior experiences across several timescales. Ecologically relevant variation in habitat exposure among postlarval and early juvenile lobsters may influence successful recruitment in this culturally and commercially important fishery species.This work was supported by a Woods Hole Oceanographic Institution Postdoctoral Scholar Award (MWJ), a National Science Foundation Graduate Research Fellowship (SRB), NOAA Saltonstall-Kennedy Grant (MWJ), and National Science Foundation Grant IOS-0843440 (JA).2018-04-0

Using Workshops to Educate Landowners About Developing Natural Resource Enterprises to Diversify Income on the Family Farm

Enterprises based on the natural resources available on farm and other private lands, such as fee-access hunting and fishing, agritourism, and wildlife watching, can provide opportunities for supplementing and diversifying income. Workshops featuring a combination of presentations and field tours were implemented throughout the southern U.S. to educate landowners on the benefits, considerations, and management of these enterprises. Participants were surveyed regarding workshop quality and future land management activities. Most landowners reported that the information gained at these events would increase revenues collected on their properties and that they expect to modify their current land use practices as a result

Toward tactilely transparent gloves: Collocated slip sensing and vibrotactile actuation

Tactile information plays a critical role in the human ability to manipulate objects with one\u27s hands. Many environments require the use of protective gloves that diminish essential tactile feedback. Under these circumstances, seemingly simple tasks such as picking up an object can become very difficult. This paper introduces the SlipGlove, a novel device that uses an advanced sensing and actuation system to return this vital tactile information to the user. Our SlipGlove prototypes focus on providing tactile cues associated with slip between the glove and a contact surface. Relative motion is sensed using optical mouse sensors embedded in the glove\u27s surface. This information is conveyed to the wearer via miniature vibration motors placed inside the glove against the wearer\u27s skin. The collocation of slip sensing and tactile feedback creates a system that is natural and intuitive to use. We report results from a human subject study demonstrating that the SlipGlove allows the wearer to approach the capabilities of bare skin in detecting and reacting to fingertip slip. Users of the SlipGlove also had significantly faster and more consistent reaction to fingertip slip when compared to a traditional glove design. The SlipGlove technology allows us to enhance human perception when interacting with real environments and move toward the goal of a tactilely transparent glove

Motor modules during adaptation to walking in a powered ankle exoskeleton

Abstract Background Modules of muscle recruitment can be extracted from electromyography (EMG) during motions, such as walking, running, and swimming, to identify key features of muscle coordination. These features may provide insight into gait adaptation as a result of powered assistance. The aim of this study was to investigate the changes (module size, module timing and weighting patterns) of surface EMG data during assisted and unassisted walking in an powered, myoelectric, ankle-foot orthosis (ankle exoskeleton). Methods Eight healthy subjects wore bilateral ankle exoskeletons and walked at 1.2 m/s on a treadmill. In three training sessions, subjects walked for 40 min in two conditions: unpowered (10 min) and powered (30 min). During each session, we extracted modules of muscle recruitment via nonnegative matrix factorization (NNMF) from the surface EMG signals of ten muscles in the lower limb. We evaluated reconstruction quality for each muscle individually using R2 and normalized root mean squared error (NRMSE). We hypothesized that the number of modules needed to reconstruct muscle data would be the same between conditions and that there would be greater similarity in module timings than weightings. Results Across subjects, we found that six modules were sufficient to reconstruct the muscle data for both conditions, suggesting that the number of modules was preserved. The similarity of module timings and weightings between conditions was greater then random chance, indicating that muscle coordination was also preserved. Motor adaptation during walking in the exoskeleton was dominated by changes in the module timings rather than module weightings. The segment number and the session number were significant fixed effects in a linear mixed-effect model for the increase in R2 with time. Conclusions Our results show that subjects walking in a exoskeleton preserved the number of modules and the coordination of muscles within the modules across conditions. Training (motor adaptation within the session and motor skill consolidation across sessions) led to improved consistency of the muscle patterns. Subjects adapted primarily by changing the timing of their muscle patterns rather than the weightings of muscles in the modules. The results of this study give new insight into strategies for muscle recruitment during adaptation to a powered ankle exoskeleton.https://deepblue.lib.umich.edu/bitstream/2027.42/140718/1/12984_2017_Article_343.pd

Recent Progress on Nonlinear Ultrasonic Testing for Materials Aging in Nuclear Applications

Materials in nuclear power plants are subjected to a variety of time-dependent aging phenomena, depending on their environmental conditions. In many cases, such phenomena cause microstructural changes in the materials before the development of macro scale damage or, eventually, component failure. Nonlinear ultrasonic testing has the potential to probe microstructural characteristics of materials that have undergone aging related changes and can potentially be used to establish structure-property relationships or predict where macro scale damage (e.g., cracking) is likely to occur. In this talk, recent work relating measured material nonlinearity to microstructural changes encountered in nuclear power applications is presented, specifically radiation damage in ferritic steels and weld sensitization in austenitic stainless steels. In the case of radiation damage, it has been established that the formation of BCC Cu nanoprecipitates and changes in dislocation density affect the material nonlinearity. In nonlinearity measurements in the case of weld sensitization (migration of Cr to grain boundaries in the heat affected zone, affecting the local corrosion resistance), it is thought formation of M23C6 carbides at the grain boundaries affects the measured material nonlinearity. Preliminary results are presented

Action spectrum of the retinal mechanism mediating nocturnal light-induced suppression of rat pineal gland N-acetyltransferase

The spectral properties of the retinal mechanism mediating the inhibitory effects of nocturnal light on pineal gland N-acetyltransferase (NAT) activity were determined. Pineal gland NAT activity declined linearly in albino rats exposed to different irradiances of a 460 or 580 nm monochromatic light during the middle of the dark phase of the cycle. The difference in sensitivity to the test lights is that predicted for a photopigment having peak absorbance at 495 nm, suggesting the inhibition of pineal gland N-acetyltransferase activity is mediated by the photopigment found in rat rods.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26770/1/0000322.pd