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Deposition of reactive nitrogen from anthropogenic sources greatly exceeds natural fluxes and, in Scotland, a large proportion of semi-natural ecosystems (i.e., communities of native species, modified to varying degrees by human activities) currently experience nitrogen deposition loads in excess of the thresholds at which adverse impacts have been reported. This review provides a summary of current knowledge on the thresholds for adverse nitrogen impacts in Scottish terrestrial semi-natural ecosystems, ecosystem responses to excess nitrogen deposition, the scope for mitigating the impacts of nitrogen deposition through habitat management and metrics which could be used to monitor ecosystem recovery.

Understanding the chemical composition of our planet's crust was one of the biggest questions of the 20th century. More than 100 years later, we are still far from understanding the global patterns in the bioavailability and spatial coupling of elements in topsoils worldwide, despite their importance for the productivity and functioning of terrestrial ecosystems. Here, we measured the bioavailability and coupling of thirteen macro- and micronutrients and phytotoxic elements in topsoils (3–8 cm) from a range of terrestrial ecosystems across all continents (∼10,000 observations) and in response to global change manipulations (∼5,000 observations). For this, we incubated between 1 and 4 pairs of anionic and cationic exchange membranes per site for a mean period of 53 days. The most bioavailable elements (Ca, Mg, and K) were also amongst the most abundant in the crust. Patterns of bioavailability were biome-dependent and controlled by soil properties such as pH, organic matter content and texture, plant cover, and climate. However, global change simulations resulted in important alterations in the bioavailability of elements. Elements were highly coupled, and coupling was predictable by the atomic properties of elements, particularly mass, mass to charge ratio, and second ionization energy. Deviations from the predictable coupling-atomic mass relationship were attributed to global change and agriculture. Our work illustrates the tight links between the bioavailability and coupling of topsoil elements and environmental context, human activities, and atomic properties of elements, thus deeply enhancing our integrated understanding of the biogeochemical connections that underlie the productivity and functioning of terrestrial ecosystems in a changing world.

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. Weassessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1–315%); this range was positively correlated withthe size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species’ populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggestspatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1–315%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species’ populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales. Fil: Wilcox, Kevin R.. Oklahoma State University; Estados Unidos Fil: Tredennick, Andrew T.. State University of Utah; Estados Unidos Fil: Koerner, Sally E.. University of North Carolina; Estados Unidos Fil: Grman, Emily. Eastern Michigan University; Estados Unidos Fil: Hallett, Lauren M.. University of Oregon; Estados Unidos Fil: Avolio, Meghan L.. University Johns Hopkins; Estados Unidos Fil: La Pierre, Kimberly J.. Smithsonian Environmental Research Center; Estados Unidos Fil: Houseman, Gregory R.. Wichita State University; Estados Unidos Fil: Forest, Isbell. University of Minnesota; Estados Unidos Fil: Johnson, David Samuel. Virginia Institute of Marine Science; Estados Unidos Fil: Alatalo, Juha M.. Qatar University; Qatar Fil: Baldwin, Andrew H.. University of Maryland; Estados Unidos Fil: Bork, Edward W.. University of Alberta; Canadá Fil: Boughton, Elizabeth H.. MacArthur Agroecology Research Center; Estados Unidos Fil: Bowman, William D.. University of Colorado; Estados Unidos Fil: Britton, Andrea J.. James Hutton Institute; Estados Unidos Fil: Cahill, James F.. University of Alberta; Canadá Fil: Collins, Scott L.. University of New Mexico; Estados Unidos Fil: Du, Guozhen. Lanzhou University; China Fil: Eskelinen, Anu. Helmholtz Centre for Environmental Research; Alemania. German Centre for Integrative Biodiversity Research; Alemania. University of Oulu; Finlandia Fil: Gough, Laura. Towson University; Estados Unidos Fil: Jentsch, Anke. University of Bayreuth; Alemania Fil: Kern, Christel. United States Forest Service; Estados Unidos Fil: Klanderud, Kari. Norwegian University of Life Sciences; Noruega Fil: Knapp, Alan K.. Colorado State University; Estados Unidos Fil: Kreyling, Juergen. Greifswald University; Alemania Fil: Luo, Yiqi. Oklahoma State University; Estados Unidos. Northern Arizona University; Estados Unidos. Tsinghua University; China Fil: McLaren, James E.. University of Texas at El Paso; Estados Unidos Fil: Megonigal, Patrick. Smithsonian Environmental Research Center; Estados Unidos Fil: Onipchenko, Vladimir. Moscow State Lomonosov University; Rusia Fil: Prevéy, Janet. Pacific Northwest Research Station; Estados Unidos Fil: Price, Jodi N.. Charles Sturt University; Australia Fil: Robinson, Clare H.. University of Manchester; Reino Unido Fil: Sala, Osvaldo Esteban. Arizona State University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Smith, Melinda D.. Colorado State University; Estados Unidos Fil: Soudzilovskaia, Nadejda A.. Leiden University; Países Bajos Fil: Souza, Lara. Oklahoma State University; Estados Unidos Fil: Tilman, David. University of Minnesota; Estados Unidos Fil: White, Shannon R.. Government of Alberta; Canadá Fil: Xu, Zhuwen. Chinese Academy of Sciences; República de China Fil: Yahdjian, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Yu, Qiang. Chinese Academy of Agricultural Sciences; China Fil: Zhang, Pengfei. Lanzhou University; China Fil: Zhang, Yunhai. Chinese Academy of Sciences; República de China. University Aarhus; Dinamarca