Atmospheric nitrogen deposition in terrestrial ecosystems: Its impact on plant communities and consequences across trophic levels

Abstract

The global nitrogen cycle has been greatly perturbed by human activities resulting in elevated nitrogen deposition in many parts of the world. The threat nitrogen deposition poses to ecosystem function and biodiversity is increasingly recognised. In terrestrial systems, impacts on the plant community are mainly through eutrophication and soil acidification. Interactions with secondary environmental drivers such as extreme weather and disease are also key mechanisms. Impacts on consumers can be caused by changes in the quality or quantity of food as a result of changes in food plant chemistry or species composition, changes in vegetation structure leading to a change in the availability of prey species, nesting sites or cooled microclimates or changes in the phenology of plants leading to causing phenological asynchrony. Primary consumers have received considerably less research attention than plants but negative impacts have been observed for both folivorous insects and pollinators. Mammal herbivores have received little research attention. New analysis of changes in plant traits along a gradient of nitrogen deposition in the UK shows that plants pollinated by large bees were negatively associated with N deposition whilst low pH was associated with lower nectar production, reduced occurrence of plants pollinated by long‐tongued insects and a reduction in plants with larger floral units. Very few studies have investigated the effects on secondary consumers, but those that have suggest that there are likely to be negative impacts. This review identifies considerable knowledge gaps in the impacts of N deposition on higher tropic levels and highlights that for many groups, knowledge of N deposition impacts is patchy at best. Evidence that has been collected suggests that there are likely to be impacts on primary and secondary consumers making this a priority area for investigation.

Human eutrophication drives biogeographic salt marsh productivity patterns in China

“…, Stevens et al. ). Within the last five years, a global data synthesis shows that nutrient availability has surpassed temperature as the major determinant of plant productivity due to nutrient deposition (Fernández‐Martínez et al.…”

Soil eutrophication shaped the composition of pollinator assemblages during the past century

“…Nitrogen is essential for many biological processes (Elser et al 2007), but due to combustion of fossil fuels and intensification of fertilizer use in agriculture and forestry (Galloway et al 2008, Sutton et al 2011, excessive nitrogen availability is a current threat for biodiversity (Öckinger et al 2006, WallisDeVries andBobbink 2017). Impacts on plant community are well-recognized, including losses in species diversity (Stevens et al 2004, Bobbink et al 2010, and these may propagate to primary consumers (Stevens et al 2018). While there has been recent research into effects on herbivores (Nijssen et al 2017, Pöyry et al 2017, WallisDeVries and van Swaay 2017, the potential effects of soil eutrophication on those feeding on pollen and nectar (potential pollinators) are largely unexplored (Stevens et al 2018, but see Betzholtz et al 2013, Tamburini et al 2017, Ramos et al 2018.…”

Plant–bacteria–soil response to frequency of simulated nitrogen deposition has implications for global ecosystem change

“…Changes brought by anthropogenic atmospheric nitrogen (N) deposition suggest potentially strong global impacts on ecosystem structure and function (Stevens, David, & Storkey, 2018;Stevens, Dise, Mountford, & Gowing, 2004). Chronic N deposition has had wide-ranging global effects, such as plant species losses, plant productivity change and the potential for carbon accrual or losses from ecosystems (Frey et al, 2014;McClean, Berg, Ashmore, & Preston, 2011;Stevens, Thompson, Grime, Long, & Gowing, 2010).…”