Abstract. To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and inter-annual variations in soil respiration (R s ), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 site-years of eddy-covariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (R e ). R s was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of R s to experimental manipulations mimicking aspects of global change or aimed at partitioning R s into component fluxes ranged from À70% to þ52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on R s was transient, but in other cases the time series were not long enough to rule out long-term changes in respiration rates. Inter-annual variations in weather and phenology induced variation among annual R s estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddy-covariance sites, aboveground respiration dominated R e early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patterns-high apparent rates of respiration during winter and very low rates in mid-to-late summer-at the Environmental Measurement Site suggest either bias in R s and R e estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hard-to-measure fluxes (e.g., wintertime R s , unaccounted losses of CO 2 from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of R e , and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this data-rich analysis identifies important seasonal and experimental variations in R s and R e and in the partitioning of R e above-vs. belowground. v www.esajournals.org 1

Abstract. Foundation species have a major impact on biotic and abiotic processes and create a stable environment for many other species. Eastern hemlock (Tsuga canadensis), a foundation tree species native to North America, is currently declining due to infestation by an invasive insect, the hemlock woolly adelgid (Adelges tsugae). Loss of hemlock canopies can greatly alter the dark, cool, and damp microclimate of hemlock forests. We studied five years of microclimatic changes following logging or girdling (to simulate physical effects of adelgid) of hemlocks in a multi-hectare-scale experiment in a New England forest. Both logging and girdling of hemlocks caused large changes in light availability, air and soil temperature, and soil moisture. Even though the impact of logging was more rapid than the effect of gradual hemlock mortality after girdling, the microclimatic changes in these two canopy treatments converged over time. The microclimate in hardwood control plots, which represent the predicted forest composition 50 years after hemlock loss, was intermediate between the two canopy treatments and the hemlock control plots. Our fine-scale results were generally consistent with average microclimatic effects observed in comparative studies but revealed additional changes in variance and seasonal rhythms, and the importance of stochastic events such as ice storms. The variance in air temperature, but not in soil temperature, greatly increased after loss of hemlock. We also observed a striking saw-tooth pattern, consisting of a small peak before budbreak in temperature differentials between hemlock control and the two canopy treatments-likely due to the insulating hemlock canopy preventing snow from melting-followed by a larger difference in temperatures after bud-break. We expect the ongoing decline of eastern hemlock-due to both infestation and pre-emptive salvage logging-to greatly impact the microclimate of hemlock forests, as well as the many taxa that are associated with it.

IntroductionDespite global progress on many measures of child health, rates of neonatal mortality remain high in the developing world. Evidence suggests that substantial improvements can be achieved with simple, low-cost interventions within family and community settings, particularly those designed to change knowledge and behaviour at the community level. Using social network analysis to identify structurally influential community members and then targeting them for intervention shows promise for the implementation of sustainable community-wide behaviour change.Methods and analysisWe will use a detailed understanding of social network structure and function to identify novel ways of targeting influential individuals to foster cascades of behavioural change at a population level. Our work will involve experimental and observational analyses. We will map face-to-face social networks of 30 000 people in 176 villages in Western Honduras, and then conduct a randomised controlled trial of a friendship-based network-targeting algorithm with a set of well-established care interventions. We will also test whether the proportion of the population targeted affects the degree to which the intervention spreads throughout the network. We will test scalable methods of network targeting that would not, in the future, require the actual mapping of social networks but would still offer the prospect of rapidly identifying influential targets for public health interventions.Ethics and disseminationThe Yale IRB and the Honduran Ministry of Health approved all data collection procedures (Protocol number 1506016012) and all participants will provide informed consent before enrolment. We will publish our findings in peer-reviewed journals as well as engage non-governmental organisations and other actors through venues for exchanging practical methods for behavioural health interventions, such as global health conferences. We will also develop a ‘toolkit’ for practitioners to use in network-based intervention efforts, including public release of our network mapping software.Trial registration numberNCT02694679; Pre-results.