Increasing soil nutrient loads of European semi-natural grasslands strongly alter plant functional diversity independently of species loss

Anthropogenically increased input of nitrogen (N) and phosphorous (P) have led to a severe reduction of plant species richness in European semi-natural grasslands. Although it is well established that this species loss is not trait neutral, a thorough analysis of the effects of nutrient addition on trait based functional diversity and functional composition, independently of species loss, is lacking so far. We compiled data on the plant species abundance (relevé’s) of 279 Nardus grasslands from nine European countries, across a gradient of soil N and P content. Functional diversity (Petchy and Gaston’s FDc, weighted FDc and quadratic entropy) and mean trait composition were calculated for each relevé, based on 21 functional traits. Differences in functional diversity and functional composition were related to differences in soil N, atmospheric N deposition, soil P and pH, while controlling for geographic location and species richness. All functional diversity measures decreased with increasing soil N, with wFDc also decreased by soil P, independent of species loss. This was accompanied by clear shifts in functional trait composition, associated with shifts from below-ground competition for nutrients to above-ground competition for light. This resulted in a decrease in insect-pollinated therophytes and chamaephytes and an increase in long-lived, clonal graminoids and hemicryptophytes under increasing soil N and P. These functional community changes can be expected to alter both ecosystem functioning and service provisioning of the studied grasslands. Our research emphasizes the importance of a reduction of both N and P emission throughout Europe for sustainable conservation of these communities

Time processing in children and adults with ADHD

A time-processing deficit has been proposed as a neuropsychological candidate endophenotype for Attention Deficit Hyperactivity Disorder (ADHD), but its developmental trajectory still needs to be explored. In the present study, children (N = 33) and adults (N = 22) with ADHD were compared to normal controls on two time-processing tasks. For time reproduction, ADHD-related impairment was found in the full group, but not when adults were analyzed separately. For the discrimination of brief intervals, children and adults with ADHD showed different patterns of deficit. We conclude that in ADHD some time-processing deficits are still present in adults, but may take on age-related different forms