Dong-Liang Cheng1, Karl J Niklas. 1. Key Laboratory of Arid and Grassland Agroecology, Lanzhou University, Ministry of Education, Lanzhou, Gansu Province 730000, China.
Abstract
BACKGROUND AND AIMS: Prior work has shown that above- and below-ground dry biomass across individual plants scale in a near isometric manner across phyletically and ecologically diverse species. Allometric theory predicts that a similar isometric scaling relationship should hold true across diverse forest-types, regardless of vegetational composition. METHODS: To test this hypothesis, two compendia for forest-level above- and below-ground dry biomass per hectare (M(A) and M(R), respectively) were examined to test the hypothesis that M(A) vs. M(R) scales isometrically and in the same manner as reported for data from individual plants. Model Type II regression protocols were used to compare the numerical values of M(A) vs. M(R) scaling exponents (i.e. slopes of log-log linear relationships) for the combined data sets (n =1534), each of the two data sets, and data sorted into a total of 17 data subsets for community- and biome-types as well as communities dominated by angiosperms or conifers. KEY RESULTS: Among the 20 regressions examined, 15 had scaling exponents that were indistinguishable from that reported for M(A) vs. M(R) across individual plants. The isometric hypothesis could not be strictly rejected on statistical grounds; four of these 15 exponents had broad 95% confidence intervals resulting from small sample sizes. Significant variation was observed in the y-intercepts of the 20 regression curves, because of absolute differences in M(A) or M(R). CONCLUSIONS: The allometries of forest- and individual plant-level M(A) vs. M(R) relationships share strikingly similar scaling exponents, but differ because of considerable variation in y-intercepts. These results support prior allometric theory and provide boundary conditions for the scaling of M(A) and M(R).
BACKGROUND AND AIMS: Prior work has shown that above- and below-ground dry biomass across individual plants scale in a near isometric manner across phyletically and ecologically diverse species. Allometric theory predicts that a similar isometric scaling relationship should hold true across diverse forest-types, regardless of vegetational composition. METHODS: To test this hypothesis, two compendia for forest-level above- and below-ground dry biomass per hectare (M(A) and M(R), respectively) were examined to test the hypothesis that M(A) vs. M(R) scales isometrically and in the same manner as reported for data from individual plants. Model Type II regression protocols were used to compare the numerical values of M(A) vs. M(R) scaling exponents (i.e. slopes of log-log linear relationships) for the combined data sets (n =1534), each of the two data sets, and data sorted into a total of 17 data subsets for community- and biome-types as well as communities dominated by angiosperms or conifers. KEY RESULTS: Among the 20 regressions examined, 15 had scaling exponents that were indistinguishable from that reported for M(A) vs. M(R) across individual plants. The isometric hypothesis could not be strictly rejected on statistical grounds; four of these 15 exponents had broad 95% confidence intervals resulting from small sample sizes. Significant variation was observed in the y-intercepts of the 20 regression curves, because of absolute differences in M(A) or M(R). CONCLUSIONS: The allometries of forest- and individual plant-level M(A) vs. M(R) relationships share strikingly similar scaling exponents, but differ because of considerable variation in y-intercepts. These results support prior allometric theory and provide boundary conditions for the scaling of M(A) and M(R).
Authors: Jörg Albrecht; Marcell K Peters; Joscha N Becker; Christina Behler; Alice Classen; Andreas Ensslin; Stefan W Ferger; Friederike Gebert; Friederike Gerschlauer; Maria Helbig-Bonitz; William J Kindeketa; Anna Kühnel; Antonia V Mayr; Henry K Njovu; Holger Pabst; Ulf Pommer; Juliane Röder; Gemma Rutten; David Schellenberger Costa; Natalia Sierra-Cornejo; Anna Vogeler; Maximilian G R Vollstädt; Hamadi I Dulle; Connal D Eardley; Kim M Howell; Alexander Keller; Ralph S Peters; Victor Kakengi; Claudia Hemp; Jie Zhang; Peter Manning; Thomas Mueller; Christina Bogner; Katrin Böhning-Gaese; Roland Brandl; Dietrich Hertel; Bernd Huwe; Ralf Kiese; Michael Kleyer; Christoph Leuschner; Yakov Kuzyakov; Thomas Nauss; Marco Tschapka; Markus Fischer; Andreas Hemp; Ingolf Steffan-Dewenter; Matthias Schleuning Journal: Nat Ecol Evol Date: 2021-09-20 Impact factor: 15.460