Forest gene diversity is correlated with the composition and function of soil microbial communities

The growing field of community and ecosystem genetics indicates that plant genotype and genotypic variation are important for structuring communities and ecosystem processes. Little is known, however, regarding the effects of stand gene diversity on soil communities and processes under field conditions. Utilizing natural genetic variation occurring in Populus spp. hybrid zones, we tested the hypothesis that stand gene diversity structures soil microbial communities and influences soil nutrient pools. We found significant unimodal patterns relating gene diversity to soil microbial community composition, microbial exoenzyme activity of a carbon‐acquiring enzyme, and availability of soil nitrogen. Multivariate analyses indicate that this pattern is due to the correlation between gene diversity, plant secondary chemistry, and the composition of the microbial community that impacts the availability of soil nitrogen. Together, these data from a natural system indicate that stand gene diversity may affect soil microbial communities and soil processes in ways similar to species diversity (i.e., unimodal patterns). Our results further demonstrate that the effects of plant genetic diversity on other organisms may be mediated by plant functional trait variation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147191/1/pope0035.pd

Rapid shifts in the chemical composition of aspen forests: an introduced herbivore as an agent of natural selection

The global ecological impacts of introduced and exotic species can be dramatic, leading to losses in biodiversity and ecosystem “meltdown”, however, the evolutionary impacts of introduced species are much less understood. Further, very few studies have examined whether mammalian herbivores can act as agents of natural selection for plant traits. We examined the hypothesis that variation in aspen phytochemistry resulted in selective herbivory by Cervus elaphus (elk), an introduced mammalian herbivore. With the experimental removal of a large elk exclosure, elk selectively eliminated 60% of an aspen population previously protected from herbivory resulting in a dramatic shift in the phytochemical composition of the aspen forest. Selection gradients (β) varied from 0.52 to 0.66, well above average relative to other studies of selection. These results indicate that introduced herbivores can have rapid evolutionary consequences even on long lived native species. Because there are fundamental links between phytochemistry, biodiversity and ecosystem processes, the effects of an introduced herbivore are likely to have cascading impacts on the services ecosystems provide

Costs and Cost-Effectiveness of the Meeting Centres Support Programme for People Living with Dementia in Italy, Poland and the UK: The MEETINGDEM Study

We examined the costs and cost-effectiveness of the Meeting Centre Support Programme (MCSP) implemented and piloted in the UK, Poland and Italy, replicating the Dutch Meeting Centre model. Dutch Meeting Centres combine day services for people with dementia with carer support. Data were collected over 2015-2016 from MCSP and usual care (UC) participants (people with dementia-carer dyads) at baseline and 6 months. We examined participants’ health and social care (HSC), and societal costs, including Meeting Centre (MC) attendances. Costs and outcomes in MCSP and UC groups were compared. Primary outcomes: Persons with dementia: quality-adjusted life years (EQ-5D-5L-derived); QOL-AD. DQoL was examined as a secondary outcome. Carers: Short Sense of Competence Questionnaire (SSCQ). Incremental costeffectiveness ratios (ICER) and cost-effectiveness acceptability curves were obtained by bootstrapping outcome and cost regression estimates. Eighty-three MCSP and 69 UC dyads were analysed. The 6-month cost of providing MCSP was €4,703; participants with dementia attended MC a mean of 45 times and carers 15 times. Including intervention costs, adjusted 6-month HSC costs were €5,941higher in MCSP than in UC. From the HSC perspective: in terms of QALY, the probability of cost-effectiveness was zero over willingness-to-pay (WTP) ranging from €0 to €350,000. On QOL-AD, the probability of cost-effectiveness of MCSP was 50% at WTP of €5,000 for a onepoint increase. A one-point gain in the DQoL positive affect subscale had a probability of cost-effectiveness of 99% at WTP over €8,000. On SSCQ, no significant difference was found between MCSP and UC. Evidence for cost-effectiveness of MCSP was mixed but suggests that it may be cost-effective in relation to gains in dementia-specific quality of life measures. MCs offer effective tailored post-diagnostic support services to both people with dementia and carers in a context where few evidence-based alternatives to formal home-based social services may be available

MEETINGDEM REPORTING ON THE IMPLEMENTATION, EFFECTIVENESS AND COST-EFFECTIVENESS OF THE DUTCH MEETING CENTRES SUPPORTS PROGRAMME FOR PEOPLE LIVING WITH DEMENTIA AND FAMILY CARERS IN THREE EUROPEAN COUNTRIES

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From genes to ecosystems: a synthesis of the effects of plant genetic factors across levels of organization

Using two genetic approaches and seven different plant systems, we present findings from a meta-analysis examining the strength of the effects of plant genetic introgression and genotypic diversity across individual, community and ecosystem levels with the goal of synthesizing the patterns to date. We found that (i) the strength of plant genetic effects can be quite high; however, the overall strength of genetic effects on most response variables declined as the levels of organization increased. (ii) Plant genetic effects varied such that introgression had a greater impact on individual phenotypes than extended effects on arthropods or microbes/fungi. By contrast, the greatest effects of genotypic diversity were on arthropods. (iii) Plant genetic effects were greater on above-ground versus below-ground processes, but there was no difference between terrestrial and aquatic environments. (iv) The strength of the effects of intraspecific genotypic diversity tended to be weaker than interspecific genetic introgression. (v) Although genetic effects generally decline across levels of organization, in some cases they do not, suggesting that specific organisms and/or processes may respond more than others to underlying genetic variation. Because patterns in the overall impacts of introgression and genotypic diversity were generally consistent across diverse study systems and consistent with theoretical expectations, these results provide generality for understanding the extended consequences of plant genetic variation across levels of organization, with evolutionary implications