Biome boundary maintained by intense belowground resource competition in world's thinnest-rooted plant community.

Autor:	Lu M; Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544; mingzhen.lu89@gmail.com william.bond@uct.ac.za lhedin@princeton.edu.; Santa Fe Institute, Santa Fe, NM 87501., Bond WJ; Department of Biological Sciences, University of Cape Town, 7701 Cape Town, South Africa; mingzhen.lu89@gmail.com william.bond@uct.ac.za lhedin@princeton.edu.; Fynbos Node, South African Environmental Observation Network, 7735 Cape Town, South Africa., Sheffer E; The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel., Cramer MD; Department of Biological Sciences, University of Cape Town, 7701 Cape Town, South Africa., West AG; Department of Biological Sciences, University of Cape Town, 7701 Cape Town, South Africa., Allsopp N; Fynbos Node, South African Environmental Observation Network, 7735 Cape Town, South Africa., February EC; Department of Biological Sciences, University of Cape Town, 7701 Cape Town, South Africa., Chimphango S; Department of Biological Sciences, University of Cape Town, 7701 Cape Town, South Africa., Ma Z; Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China., Slingsby JA; Department of Biological Sciences, University of Cape Town, 7701 Cape Town, South Africa.; Fynbos Node, South African Environmental Observation Network, 7735 Cape Town, South Africa.; Centre for Statistics in Ecology, the Environment and Conservation, University of Cape Town, 7701 Cape Town, South Africa., Hedin LO; Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544; mingzhen.lu89@gmail.com william.bond@uct.ac.za lhedin@princeton.edu.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2022 Mar 01; Vol. 119 (9).
DOI:	10.1073/pnas.2117514119
Abstrakt:	Recent findings point to plant root traits as potentially important for shaping the boundaries of biomes and for maintaining the plant communities within. We examined two hypotheses: 1) Thin-rooted plant strategies might be favored in biomes with low soil resources; and 2) these strategies may act, along with fire, to maintain the sharp boundary between the Fynbos and Afrotemperate Forest biomes in South Africa. These biomes differ in biodiversity, plant traits, and physiognomy, yet exist as alternative stable states on the same geological substrate and in the same climate conditions. We conducted a 4-y field experiment to examine the ability of Forest species to invade the Fynbos as a function of growth-limiting nutrients and belowground plant-plant competition. Our results support both hypotheses: First, we found marked biome differences in root traits, with Fynbos species exhibiting the thinnest roots reported from any biome worldwide. Second, our field manipulation demonstrated that intense belowground competition inhibits the ability of Forest species to invade Fynbos. Nitrogen was unexpectedly the resource that determined competitive outcome, despite the long-standing expectation that Fynbos is severely phosphorus constrained. These findings identify a trait-by-resource feedback mechanism, in which most species possess adaptive traits that modify soil resources in favor of their own survival while deterring invading species. Our findings challenge the long-held notion that biome boundaries depend primarily on external abiotic constraints and, instead, identify an internal biotic mechanism-a selective feedback among traits, plant-plant competition, and ecosystem conditions-that, along with contrasting fire regime, can act to maintain biome boundaries. Competing Interests: The authors declare no competing interest. (Copyright © 2022 the Author(s). Published by PNAS.)
Databáze:	MEDLINE
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