Assessment of the cumulative effects of restoration activities on water quality in Tampa Bay, Florida.

Habitat and water quality restoration projects are commonly used to enhance coastal resources or mitigate negative impacts of water quality stressors. Significant resources have been expended for restoration projects, yet much less attention has focused on evaluating broad regional outcomes beyond site-specific assessments. This study presents an empirical framework to evaluate multiple datasets in the Tampa Bay area (Florida, USA) to identify 1) the types of restoration projects that have produced the greatest improvements in water quality, and 2) over which time frames different projects may produce water quality benefits. Information on the location and date of completion of 887 restoration projects from 1971 to 2017 were spatially and temporally matched with water quality records at each of 45 long-term monitoring stations in Tampa Bay. The underlying assumption was that the developed framework could identify differences in water quality changes between types of restoration projects based on aggregate estimates of chlorophyll-a concentrations before and after the completion of one to many projects. Water infrastructure projects to control point source nutrient loading into the Bay were associated with the highest likelihood of chlorophyll-a reduction, particularly for projects occurring prior to 1995. Habitat restoration projects were also associated with reductions in chlorophyll-a, although the likelihood of reductions from the cumulative effects of these projects were less than those from infrastructure improvements alone. The framework is sufficiently flexible for application to different spatiotemporal contexts and could be used to develop reasonable expectations for implementation of future water quality restoration activities throughout the Gulf of Mexico.

Putting Climate Adaptation on the Map: Developing Spatial Management Strategies for Whitebark Pine in the Greater Yellowstone Ecosystem.

Natural resource managers face the need to develop strategies to adapt to projected future climates. Few existing climate adaptation frameworks prescribe where to place management actions to be most effective under anticipated future climate conditions. We developed an approach to spatially allocate climate adaptation actions and applied the method to whitebark pine (WBP; Pinus albicaulis) in the Greater Yellowstone Ecosystem (GYE). WBP is expected to be vulnerable to climate-mediated shifts in suitable habitat, pests, pathogens, and fire. We spatially prioritized management actions aimed at mitigating climate impacts to WBP under two management strategies: (1) current management and (2) climate-informed management. The current strategy reflected management actions permissible under existing policy and access constraints. Our goal was to understand how consideration of climate might alter the placement of management actions, so the climate-informed strategies did not include these constraints. The spatial distribution of actions differed among the current and climate-informed management strategies, with 33-60% more wilderness area prioritized for action under climate-informed management. High priority areas for implementing management actions include the 1-8% of the GYE where current and climate-informed management agreed, since this is where actions are most likely to be successful in the long-term and where current management permits implementation. Areas where climate-informed strategies agreed with one another but not with current management (6-22% of the GYE) are potential locations for experimental testing of management actions. Our method for spatial climate adaptation planning is applicable to any species for which information regarding climate vulnerability and climate-mediated risk factors is available.

Slow lifelong growth predisposes Populus tremuloides trees to mortality.

Widespread dieback of aspen forests, sometimes called sudden aspen decline, has been observed throughout much of western North America, with the highest mortality rates in the southwestern United States. Recent aspen mortality has been linked to drought stress and elevated temperatures characteristic of conditions expected under climate change, but the role of individual aspen tree growth patterns in contributing to recent tree mortality is less well known. We used tree-ring data to investigate the relationship between an individual aspen tree's lifetime growth patterns and mortality. Surviving aspen trees had consistently higher average growth rates for at least 100 years than dead trees. Contrary to observations from late successional species, slow initial growth rates were not associated with a longer lifespan in aspen. Aspen trees that died had slower lifetime growth and slower growth at various stages of their lives than those that survived. Differences in average diameter growth between live and dead trees were significant (α = 0.05) across all time periods tested. Our best logistical model of aspen mortality indicates that younger aspen trees with lower recent growth rates and higher frequencies of abrupt growth declines had an increased risk of mortality. Our findings highlight the need for species-specific mortality functions in forest succession models. Size-dependent mortality functions suitable for late successional species may not be appropriate for species with different life history strategies. For some early successional species, like aspen, slow growth at various stages of the tree's life is associated with increased mortality risk.

The effects of group cycling on gait and pain-related disability in individuals with mild-to-moderate knee osteoarthritis: a randomized controlled trial.

STUDY DESIGN: Randomized controlled trial. OBJECTIVE: To determine the effectiveness of a community-based program of stationary group cycling on gait, pain, and physical function in individuals with mild-to-moderate knee osteoarthritis (OA). BACKGROUND: Knee pain and disability are common symptoms in individuals with knee OA. Though exercise for knee OA has acknowledged benefits, it has the potential to aggravate symptoms in some instances. METHODS: Thirty-seven subjects (27 women, 10 men) with a mean ± SD age of 57.7 ± 9.8 years were randomly assigned to a cycling (n = 19) or control (n = 18) group for a 12-week intervention study. Outcome variables, measured at baseline and 12 weeks, included preferred and maximal gait velocity, a visual analog pain scale at rest and following a 6-minute walk test, muscle strength, and functional-outcome questionnaires. Data were analyzed using mixed-model analyses of variance for group and time differences. RESULTS: After 12 weeks, the individuals receiving the cycling intervention showed significantly greater improvements (P<.05) for preferred gait velocity (mean difference between groups, 8.7 cm/s; 95% confidence interval [CI]: 2.2, 15.1), visual analog pain scale on the 6-minute walk test (mean difference, 16.5 mm; 95% CI: 2.1, 31.0), the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale (mean difference, 14.9 points; 95% CI: 2.6, 27.0) and stiffness subscale (mean difference, 10.8 points; 95% CI: 0.7, 21.3), the Knee injury and Osteoarthritis Outcome Score pain subscale (mean difference, 13.3 points; 95% CI: 3.4, 23.3), and the Knee Outcome Survey activities of daily living subscale (mean difference, 13.9 points; 95% CI: 2.0, 25.9) compared to controls. CONCLUSION: Stationary group cycling may be an effective exercise option for individuals with mild-to-moderate knee OA and may reduce pain with walking. US trial registration NCT00917618. LEVEL OF EVIDENCE: Therapy, level 1b-.