Human impacts and aridity differentially alter soil N availability in drylands worldwide

Delgado-Baquerizo, Manuel; Maestre, Fernando T.; Gallardo, Antonio; Eldridge, David J.; Soliveres, Santiago; Bowker, Matthew A.; Prado-Comesaña, Ana; Gaitán, Juan; Quero, José L.; Ochoa, Victoria; Gozalo, Beatriz; García-Gómez, Miguel; García-Palacios, Pablo; Berdugo, Miguel; Valencia, Enrique; Escolar, Cristina; Arredondo, Tulio; Barraza-Zepeda, Claudia; Boeken, Bertrand R.; Bran, Donaldo; ... (2016). Human impacts and aridity differentially alter soil N availability in drylands worldwide. Global Ecology and Biogeography, 25(1), pp. 36-45. Wiley-Blackwell 10.1111/geb.12382

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Aims Climate and human impacts are changing the nitrogen (N) inputs and losses in terrestrial ecosystems. However, it is largely unknown how these two major drivers of global change will simultaneously influence the N cycle in drylands, the largest terrestrial biome on the planet. We conducted a global observational study to evaluate how aridity and human impacts, together with biotic and abiotic factors, affect key soil variables of the N cycle. Location Two hundred and twenty-four dryland sites from all continents except Antarctica widely differing in their environmental conditions and human influence. Methods Using a standardized field survey, we measured aridity, human impacts (i.e. proxies of land uses and air pollution), key biophysical variables (i.e. soil pH and texture and total plant cover) and six important variables related to N cycling in soils: total N, organic N, ammonium, nitrate, dissolved organic:inorganic N and N mineralization rates. We used structural equation modelling to assess the direct and indirect effects of aridity, human impacts and key biophysical variables on the N cycle. Results Human impacts increased the concentration of total N, while aridity reduced it. The effects of aridity and human impacts on the N cycle were spatially disconnected, which may favour scarcity of N in the most arid areas and promote its accumulation in the least arid areas. Main conclusions We found that increasing aridity and anthropogenic pressure are spatially disconnected in drylands. This implies that while places with low aridity and high human impact accumulate N, most arid sites with the lowest human impacts lose N. Our analyses also provide evidence that both increasing aridity and human impacts may enhance the relative dominance of inorganic N in dryland soils, having a negative impact on key functions and services provided by these ecosystems.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Biodiversity

UniBE Contributor:

Soliveres, Santiago

Subjects:

500 Science > 580 Plants (Botany)

ISSN:

1466-822X

Publisher:

Wiley-Blackwell

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

24 Feb 2016 15:59

Last Modified:

08 Sep 2017 14:08

Publisher DOI:

10.1111/geb.12382

Uncontrolled Keywords:

Aridity; depolymerization; global change; human impacts; mineralization; N cycle

BORIS DOI:

10.7892/boris.75869

URI:

https://boris.unibe.ch/id/eprint/75869

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