Title: | Defoliating Insect Mass Outbreak Affects Soil N Fluxes and Tree N Nutrition in Scots Pine Forests |
Author(s): | Gruning MM; Simon J; Rennenberg H; A LM; |
Address: | "Department of Soil Science of Temperate Ecosystems, Georg-August Universitat GottingenGottingen, Germany. Ecology, Department of Biology, University of KonstanzKonstanz, Germany. Chair of Tree Physiology, Institute of Forest Sciences, University of FreiburgFreiburg, Germany. King Saud UniversityRiyadh, Saudi Arabia" |
ISSN/ISBN: | 1664-462X (Print) 1664-462X (Electronic) 1664-462X (Linking) |
Abstract: | "Biotic stress by mass outbreaks of defoliating pest insects does not only affect tree performance by reducing its photosynthetic capacity, but also changes N cycling in the soil of forest ecosystems. However, how insect induced defoliation affects soil N fluxes and, in turn, tree N nutrition is not well-studied. In the present study, we quantified N input and output fluxes via dry matter input, throughfall, and soil leachates. Furthermore, we investigated the effects of mass insect herbivory on tree N acquisition (i.e., organic and inorganic (15)N net uptake capacity of fine roots) as well as N pools in fine roots and needles in a Scots pine (Pinus sylvestris L.) forest over an entire vegetation period. Plots were either infested by the nun moth (Lymantria monacha L.) or served as controls. Our results show an increased N input by insect feces, litter, and throughfall at the infested plots compared to controls, as well as increased leaching of nitrate. However, the additional N input into the soil did not increase, but reduce inorganic and organic net N uptake capacity of Scots pine roots. N pools in the fine roots and needles of infested trees showed an accumulation of total N, amino acid-N, protein-N, and structural N in the roots and the remaining needles as a compensatory response triggered by defoliation. Thus, although soil N availability was increased via surplus N input, trees did not respond with an increased N acquisition, but rather invested resources into defense by accumulation of amino acid-N and protein-N as a survival strategy" |
Keywords: | N fluxes N metabolites feces inorganic N litter nitrate organic N throughfall; |
Notes: | "PubMed-not-MEDLINEGruning, Maren M Simon, Judy Rennenberg, Heinz L-M-Arnold, Anne eng Switzerland 2017/06/24 Front Plant Sci. 2017 Jun 7; 8:954. doi: 10.3389/fpls.2017.00954. eCollection 2017" |