WARMING AND CHRONIC HIGH NUTRIENT MANIPULATIONS YIELD DIFFERING LEGACY EFECTS ON THE SOIL MICROBIAL COMMUNITY AND NUTRIENT POOLS IN THE LOW ARCTIC

Climate warming is predicted to increase summer air temperatures in the Arctic, warming soils and enhancing microbial decomposition of soil organic matter. Given the size of the soil carbon stores in the Arctic, even a fraction of its release as CO2 to the atmosphere could result in a positive feedback to climate warming. Fertilizers have been used in the past to quickly increase soil solution nutrients pools to mimic predicted concentrations under climate warming. However, because it may have inadvertent affects on the soil microbial community, fertilizer-induced patterns in microbial decomposition may be unrealistic. This study aimed to better understand the proposed mechanism of enhanced microbial decomposition under nutrient addition and warming treatments to discern whether warming alone is enough to stimulate enhanced microbial decomposition, or if nutrients in excess (i.e. chronic high nutrient additions) are necessary to yield such a response. I investigated the impacts of 10 years of greenhouse summer warming, chronic low nutrient factorial addition (5 g N and 1g P m-2 year-1, respectively), and chronic high nutrient factorial addition (10 g N and 5g P m-2 year-1, respectively) treatments on a mesic birch hummock tundra ecosystem near Daring Lake, NWT, Canada. Soil microbial nutrient pools, soil solution nutrient pools, and microbial community structure were measured in the upper organic, lower organic, and uppermost mineral soil depth intervals of all treatment plots in Spring 2014. Interestingly, the low nutrient additions did not yield any significant trends, yet the warming treatment increased soil bacterial richness suggesting a legacy effect of warming from the previous summers. Enhanced microbial nutrient uptake occurred only in the high nutrient addition treatments, and did not significantly alter soil carbon at least within the ten year period of this experiment. Together, these results and the absence of significant impacts of the low nutrient and greenhouse warming treatments suggests that nutrient and carbon cycling in these low arctic soils may be resilient against climate warming, at least over the initial decades.

HOME-BASED REHABILITATION AND ITS IMPACT ON HOSPITAL UTILIZATION

There is compelling evidence for the effectiveness of home-based occupational therapy and physiotherapy rehabilitation for community dwelling elderly who may struggle with basic activities and the functions of daily living and mobility. Nonetheless, an estimated 2% of home care’s elderly clients receive these therapies. Ontario’s home care data indicates that 78% of clients that could benefit from these specific therapies are not receiving them. The study examined a subset of elderly clients receiving home care following a hospital discharge during 2009-2010. The aim of this study was to: understand the difference between those home care clients who received occupational therapy or physiotherapy and those who did not; and determine if receiving these therapies impacted the utilization of hospital emergency departments and inpatient admissions. A retrospective cohort design and multivariate and survival analysis of hospital and home care administrative data structured the study. Results suggest that home-based rehabilitation is offered to a minority of the home care population. Distinct client characteristics and process variables significantly associated with the increased likelihood of receiving home-based occupational and physical therapies included: clients who were older, females, admitted to home care from hospital inpatient units, assessed as non-acute for clinical and service needs and required more home making support and assistance with activities of daily living. Almost one quarter of the total sample returned to hospital. Visits to emergency departments accounted for the greater part of hospital utilization and primarily for sub-acute general symptoms and signs, post-procedural complications, infections or acute episodes from chronic obstructive pulmonary disease and renal failure. Slightly over half of the clients returning to hospital did not receive home-based rehabilitation. Clients who received occupational therapy returned to the hospital sooner following their home care admission whereas clients receiving physiotherapy spent the longest time before rehospitalizing. The majority of the clients receiving occupational therapy were admitted to home care having just resolved sub-acute conditions or symptoms, many of which are known to influence functional and physical decline. Moreover, analysis of process variables indicated that the wait time for a referral to occupational therapy was two times longer compared to physiotherapy. These same clients also waited, on average, over one month before an occupational therapist’s first visit. The need to discriminate who receives home-based rehabilitation is essential to understanding how specific therapies contribute to improving systems outcomes. This study is the first examination that focuses specifically on home-based occupational therapy and physiotherapy rehabilitation and the client characteristics and process variables associated with receiving/not receiving these therapies and the impact these factors have on the time-to-rehospitalization.