Plant species leave a chemical signature in the soils below them, generating fine-scale spatial variation that drives ecological processes. Since the publication of a seminal paper on plant-mediated soil heterogeneity by Paul Zinke in 1962, a robust literature has developed examining effects of individual plants on their local environments (individual plant effects). Here, we synthesize this work using meta-analysis to show that plant effects are strong and pervasive across ecosystems on six continents. Overall, soil properties beneath individual plants differ from those of neighbours by an average of 41%. Although the magnitudes of individual plant effects exhibit weak relationships with climate and latitude, they are significantly stronger in deserts and tundra than forests, and weaker in intensively managed ecosystems. The ubiquitous effects of plant individuals and species on local soil properties imply that individual plant effects have a role in plant -soil feedbacks, linking individual plants with biogeochemical processes at the ecosystem scale.

The global nitrogen (N) cycle has been transformed by human use of reactive N as a consequence of increased demand for food and energy. Given the considerable impact of humans on the N cycle, it is essential that we raise awareness amongst the public and policy makers as this is the first step in providing individuals and governments the opportunity to reduce their impact on the N cycle and reduce the environmental and health consequences of N pollution. Here we describe an N footprint tool for the UK developed as part of the N-PRINT program. The current per capita N footprint in the UK is 27.1 kg N per capita per year with food production constituting the largest proportion of the footprint (18.0 kg N per capita per year). Calculating an N footprint for 1971 (26.0 kg N per capita per year) demonstrates that per capita N footprints have increased slightly. The average UK footprint is smaller than that found in the USA but is higher than the Netherlands and Germany. Scenario analysis demonstrates that reducing food protein consumption to the levels recommended by the FAO and World Health Organization reduces the overall N footprint by 33%. Consuming a vegetarian diet and consuming only sustainable food both decreased the N footprint by 15% but changes in energy use have a much smaller impact.

Nitrogen (N) deposition is a major cause of plant biodiversity loss, with serious implications for appropriate management of protected sites. Reducing N emissions is the only long-term solution. However, on-site management has the potential to mitigate some of the adverse effects of N deposition. In this paper we review how management activities such as grazing, cutting, burning, hydrological management and soil disturbance measures can mitigate the negative impacts of N across a range of temperate habitats (acid, calcareous and neutral grasslands, sand dunes and other coastal habitats, heathlands, bogs and fens). The review focuses mainly on European habitats, which have a long history of N deposition, and it excludes forested systems. For each management type we distinguish between actions that improve habitat suitability for plant species of conservation importance, and actions that immobilize N or remove it from the system. For grasslands and heathlands we collate data on the quantity of N removal by each management type. Our findings show that while most activities improve habitat suitability, the majority do little to slow or to reduce the amount of N accumulating in soil pools at current deposition rates. Only heavy cutting/mowing with removal in grasslands, high intensity burns in heathlands and sod cutting remove more N than comes in from deposition under typical management cycles. We conclude by discussing some of the unintended consequences of managing specifically for N impacts, which can include damage to non-target species, alteration of soil processes, loss of the seedbank and loss of soil carbon.

Background and aims Global change drivers such as climate change influence decomposition by altering extrinsic site conditions and intrinsic litter traits. This study aimed to quantify the relative importance of these two pathways for litter decomposition in tropical forests. Methods The effects of soil nutrient availability, mean annual precipitation (MAP), and leaf litter chemistry on decomposition were isolated by measuring mass loss of leaf litter from 10 tropical tree species transplanted to 19 sites along independent gradients of soil fertility and precipitation in Panama. Across species, litter nitrogen (N) content ranged from 7.1 to 13 mg N g −1 and phosphorus (P) from 0.077 to 0.56 mg P g −1. Across sites, soil N content ranged from 1.7 to 5.5 g N kg , and MAP from 1900 to 2700 mm. Results Variation in leaf litter mass loss was explained largely by litter species identity (55 %). Site only explained a small, but significant, amount of variance (6.5 %); soil C:N ratio explained this response. Notably, neither litter nutrient content nor MAP were significant predictors of litter decomposition. Conclusions Changes in tree species composition may influence decomposition rates more than changes to site conditions.