2024-03-29T09:08:24Zhttp://buleria.unileon.es/oai/requestoai:buleria.unileon.es:10612/74222020-12-10T08:58:13Zcom_10612_17col_10612_18
Time- and age-related effects of experimentally simulated nitrogen deposition on the functioning of montane heathland ecosystems
Calvo Fernández, Javier
Taboada Palomares, Ángela
Fichtner, Andreas
Härdtle, Werner
Calvo Galván, María Leonor
Marcos Porras, Elena María
Ecologia
Ecología. Medio ambiente
P. 149-159
Ecosystems adapted to low nitrogen (N) conditions such as Calluna-heathlands are especially sensitive to enhanced
atmospheric N deposition that affects many aspects of ecosystem functioning like nutrient cycling,
soil properties and plant-microbial-enzyme relationships. We investigated the effects of five levels of experimentally-
simulated N deposition rates (i.e., N fertilization treatments: 0, 10, 20 and 50 kg N ha− 1 yr− 1 for
3 years, and 56 kg N ha− 1 yr− 1 for 10 years) on: plant, litter, microbial biomass and soil nutrient contents,
soil extracellular enzymatic activities, and plant root ericoid mycorrhizal colonization. The study was conducted
in marginal montane Calluna-heathlands at different developmental stages resulting from management
(young/building-phase and mature-phase). Our findings revealed that many soil properties did not show a statistically
significant response to the experimental addition of N, including: total N, organic carbon (C), C:N
ratio, extractable N-NO3
−, available phosphorus (P), urease and β-glucosidase enzyme activities, and microbial
biomass C and N. Our results also evidenced a considerable positive impact of chronic (10-year) high-N
loading on soil extractable N-NH4
+, acid phosphatase enzyme activity, Calluna root mycorrhizal colonization
by ericoid fungi, Calluna shoot N and P contents, and litter N content and N:P ratio. The age of heathland
vegetation influenced the effects of N addition on ericoid mycorrhizal colonization, resulting in higher colonized
roots in young heathlands at the control, low and medium N-input rates; and in mature ones at the high
and chronically high N rates. Also, young heathlands exhibited greater soil extractable N-NO3
−, available P,
microbial biomass N, Calluna shoot N and P contents, and litter N content, compared to mature ones. Our
results highlighted that accounting for the N-input load and duration, as well as the developmental stage of
the vegetation, is important for assessing the effects of added N, particularly at the heathlands' southern distribution
limit.
2018-03-03T11:45:25Z
2018-03-03T11:45:25Z
2017-03-03
info:eu-repo/semantics/article
Science of the total environment, 2017, vol. 613-614
http://hdl.handle.net/10612/7422
info:eu-repo/semantics/openAccess
Elsevier