The Effects of Forest Thinning Practices and Altered Nutrient Supply on Soil Trace Gas Fluxes in Colorado

Increases in wildfire activity in the western United States have prompted land managers to reevaluate management practices. In the Colorado Front Range, where population density is high, there is often a great concern regarding wildfire which leads to efforts that will reduce fire hazard. The most common method of achieving this goal is to thin the forest of small diameter trees. Oftentimes these practices are undertaken with little knowledge of the ecological consequences of such treatments. We investigated the effect(s) of three treatments (control, thinning-only and broadcast chipping) on trace gas fluxes (CO2, CH4, and N2O), litter mass, and soil carbon and nitrogen. In a small plot study, we used a 2 × 3 × 3 randomized complete block design to determine the influence of nutrient amendments (woodchips, nitrogen, and phosphorus availability) on trace gas fluxes. The stand-management study revealed that neither thinning-only nor broadcast chipping significantly affected soil carbon or nitrogen, while thinning-only significantly reduced the amount of forest floor litter. Each trace gas flux was significantly affected by the date of sampling (June or August). CO2 and N2O fluxes each had a significant interaction between treatment and sampling date. We attribute this to a difference in moisture availability between the sampling times. In the plot study we found that only the interaction between woodchip addition and phosphorus availability significantly affected CO2 flux. Nitrous oxide fluxes were not significantly affected by any combination, however, methane uptake was found to respond significantly to different nitrogen and phosphorus levels.

Use of infrared thermography to detect reactions to stressful events:does animal personality matter?

The study of the relationship between animal stress and personality for free-ranging animals is limited and provides contrasting results.The perception of stressors by an individual may vary due to its personality,and certain personality traits may help individuals to better cope with them.Using non-invasive infrared thermography(IRT),we investigated the link between physiological and behavioral components expressed during an acute stress event by free-ranging Fremont’s squirrels(Tamiasciurus fremonti).We expected that,during the acute stress event of being approached by the researcher,individuals that showed a fast pace-of-life syndrome(bolder,more active,and less social/more aggressive)based on an arena test would exhibit stronger sympathetic-adrenal-medullary system reactivity showing a more intense stress-induced hyperthermia(high core body temperature and low peripheral temperature)than individuals with a slow pace of life(shy,less active,and more social).We successfully employed IRT technology to images of Fremont’s squirrels with identification of the individuals’body parts(eye,nose,ear,hind foot).However,we found no support for our hypothesis.Squirrels’body surface temperatures told us more about a squirrel’s external environment and less about the thermal state of the body in that environment following a stressful event.Further studies need to assess how to make IRT effective and efficient in the field and improve its performance in studying the relationships between physiology and personality in wildlife.

Modeling visitor use on high elevation mountain trails: An example from Longs Peak in Rocky Mountain National Park, USA

Increasing use on mountain summits has both social and ecological implications.High numbers of visitors climbing mountain summits can be a safety issue,particularly in areas where terrain or elevation leads to queueing that may cause time delays.Estimating visitor use levels at site specific locations en route to summits is needed to understand the potential benefits and impacts of visitor use in these locations.However,it can be difficult to obtain reliable and robust data to estimate use and develop statistical relationships because of the remote and harsh climates on mountain summits,as well as the financial and personnel requirements involved to collect the data in remote locations.In 2015,data were collected on the higher stretches of the Keyhole Route on Longs Peak in Rocky Mountain National Park,USA(RMNP)to better understand use levels near the summit and to explore potential statistical relationships to trailhead use data that are relatively easy to collect.Strong statistical relationships from robust regression analyses were found between trailhead use counts and daily and hourly use totals on the"Homestretch"which is a final section of the Keyhole Route.Additionally,a strong statistical relationship was found between total daily use and maximum hourly use on the Homestretch.The results suggest that trailhead counts are an accurate and reliable means from which to estimate use levels on upper portions of the Keyhole route.Moreover,this research demonstrates the usefulness of an approach using proxy variables to estimate visitor use along remote peaks where data collection can be difficult.These types of data can elucidate various options and decisions for park management teams who are charged with deciding if and how to manage high use areas.

Behavioral responses to spatial heterogeneity in endangered Ganges River dolphins(Platanista gangetica gangetica)

Globally,the threat of endangerment and extinction of small cetaceans was highlighted after the recent extinction of the Chinese River dolphin or Baiji(Lipotes vexillifer).Species with a small population size and a limited geographic range,such as Ganges River dolphins(GRD),are more vulnerable to extinction.The social and behavioral needs of cetaceans have been identified as potential factors increasing their vulnerability to human disturbance.However,little is known about how GRD adapt their behaviors and diel activity patterns to spatiotemporal variation.In this paper,we examined the underwater behavior of GRDs in Nepal by collecting echolocation clicks from three spatially stratified habitats in the Sapta Koshi River system over a six-month period.Our research found that GRDs behave differently in response to spatial heterogeneity,indicating diverse environmental requirements for GRD persistence.Behavioral activity and duration varied across habitats but not across time of day,suggesting that GRD behaviors are likely to be regulated by habitat structure regardless of the time of day.However,GRD consistently exhibited nocturnal activity peaks even when diurnal activity varied substantially.This indicates that river dolphins may favor nocturnal refuges as a reaction to human disturbance in highly regulated rivers.Managing human disturbances in conjunction with habitat heterogeneity can improve the persistence of riverine cetaceans.Here,we document behavioral and ecological information pertaining to GRD,which is essential to the formation of river dolphin recovery plans that link ecological perspectives to planning and management.