Title
Human impacts and aridity differentially alter soil N availability in drylands worldwide
Date Issued
01 January 2016
Access level
metadata only access
Resource Type
journal article
Author(s)
Delgado-Baquerizo M.
Maestre F.T.
Gallardo A.
Eldridge D.J.
Soliveres S.
Bowker M.A.
Prado-Comesaña A.
Gaitán J.
Quero J.L.
Ochoa V.
Gozalo B.
García-Gómez M.
García-Palacios P.
Berdugo M.
Valencia E.
Escolar C.
Arredondo T.
Barraza-Zepeda C.
Boeken B.R.
Bran D.
Cabrera O.
Carreira J.A.
Chaieb M.
Conceição A.A.
Derak M.
Ernst R.
Espinosa C.I.
Florentino A.
Gatica G.
Ghiloufi W.
Gómez-González S.
Gutiérrez J.R.
Hernández R.M.
Huber-Sannwald E.
Jankju M.
Mau R.L.
Miriti M.
Monerris J.
Morici E.
Muchane M.
Naseri K.
Pucheta E.
Ramírez E.
Romão R.L.
Tighe M.
Torres D.
Torres-Díaz C.
Val J.
Veiga J.P.
Wang D.
Yuan X.
Zaady E.
Publisher(s)
Blackwell Publishing Ltd
Abstract
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.
Start page
36
End page
45
Volume
25
Issue
1
Language
English
OCDE Knowledge area
Investigación climática Ciencia del suelo
Scopus EID
2-s2.0-84955189434
Source
Global Ecology and Biogeography
ISSN of the container
1466822X
Sponsor(s)
Seventh Framework Programme (242658)
Sources of information: Directorio de Producción Científica Scopus