Long-term nitrogen and phosphorus enrichment alters vegetation species composition and reduces carbon storage in upland soil

Stiles, William A.V.; Rowe, Edwin C. ORCID: https://orcid.org/0000-0003-4784-7236; Dennis, Peter. 2017 Long-term nitrogen and phosphorus enrichment alters vegetation species composition and reduces carbon storage in upland soil. Science of the Total Environment, 593-594. 688-694. 10.1016/j.scitotenv.2017.03.136

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Official URL: http://dx.doi.org/10.1016/j.scitotenv.2017.03.136

Abstract/Summary

Reactive nitrogen (N) deposition can affect ecosystem processes, particularly in oligotrophic upland habitats. Phosphorus (P) addition has been proposed to reduce the effects of N enrichment on N leaching and acidification, since P limitation can reduce biomass production and consequent sequestration of reactive N. However, biodiversity is often reduced in more productive ecosystems and P limitation may protect against this effect. Responses to P availability in instances of high N deposition are poorly understood. This study investigated the ecosystem response to alleviation of P limitation, using a long-term nutrient addition experiment (1996–2012) three years after ceasing N inputs and 15 years after a single P application. Substantial differences were observed in the structure and composition of vegetation species and above-ground vegetation biomass. Vegetation height was greater in the N + P addition treatments (+ 38% cf. control), with increased cryptogam cover (+ 47%), whereas N addition increased graminoid species cover (+ 68%). Vegetation diversity was significantly reduced by the addition of P (− 21%), indicating that P limitation is likely to be an important mechanism that limits biodiversity loss in upland habitats exposed to chronic N deposition. Significant differences in soil C and N contents were also observed between treatments. Relative to control, the addition of N increased soil C (+ 11%) and N (+ 11%) pool sizes, whereas the addition of N and P reduced soil C (− 12%) and N (− 13%) pool sizes. This demonstrated the importance of P availability for upland ecosystem processes, and highlights the long-term effects of P addition on vegetation species composition and C storage. Thus, the addition of P cannot be endorsed as a method for reducing impacts of N deposition.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.scitotenv.2017.03.136
UKCEH and CEH Sections/Science Areas:	Emmett
ISSN:	0048-9697
Additional Keywords:	nitrogen deposition, phosphorus limitation, mosses, vascular plants, soil carbon
NORA Subject Terms:	Agriculture and Soil Science
Date made live:	18 Apr 2017 13:34 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/516872

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.scitotenv.2017.03.136

UKCEH and CEH Sections/Science Areas:

Emmett

ISSN:

0048-9697

Additional Keywords:

nitrogen deposition, phosphorus limitation, mosses, vascular plants, soil carbon

NORA Subject Terms:

Agriculture and Soil Science