Positive feedbacks and alternative stable states in forest leaf types
Authors: Zou Yibiao , Zohner Constantin M. , Averill Colin , Ma Haozhi , Merder Julian , Berdugo Miguel , Bialic-Murphy Lalasia , Mo Lidong , Brun Philipp , Zimmermann Niklaus E. , Liang Jingjing , de-Miguel Sergio , Nabuurs Gert-Jan , Reich Peter B. , Niinements Ulo , Dahlgren Jonas , Kändler Gerald , Ratcliffe Sophia , Ruiz-Benito Paloma , de Zavala Miguel Angel ,   GFBI consortium, Abegg Meinrad , Adou Yao Yves C. , Alberti Giorgio , Almeyda Zambrano Angelica M. , Alvarado Braulio Vilchez , Alvarez-Dávila Esteban , Alvarez-Loayza Patricia , Alves Luciana F. , Ammer Christian , Antón-Fernández Clara , Araujo-Murakami Alejandro , Arroyo Luzmila , Avitabile Valerio , Aymard Gerardo A. , Baker Timothy R. , Bałazy Radomir , Banki Olaf , Barroso Jorcely G. , Bastian Meredith L. , Bastin Jean-Francois , Birigazzi Luca , Birnbaum Philippe , Bitariho Robert , Boeckx Pascal , Bongers Frans , Bouriaud Olivier , Brancalion Pedro H. S. , Brandl Susanne , Brearley Francis Q. , Brienen Roel , Broadbent Eben N. , Bruelheide Helge , Bussotti Filippo , Gatti Roberto Cazzolla , César Ricardo G. , Cesljar Goran , Chazdon Robin , Chen Han Y. H. , Chisholm Chelsea , Cho Hyunkook , Cienciala Emil , Clark Connie , Clark David , Colletta Gabriel D. , Coomes David A. , Valverde Fernando Cornejo , Corral-Rivas José J. , Crim Philip M. , Cumming Jonathan R. , Dayanandan Selvadurai , de Gasper André L. , Decuyper Mathieu , Derroire Géraldine , DeVries Ben , Djordjevic Ilija , Dolezal Jiri , Dourdain Aurélie , Obiang Nestor Laurier Engone , Enquist Brian J. , Eyre Teresa J. , Fandohan Adandé Belarmain , Fayle Tom M. , Feldpausch Ted R. , Ferreira Leandro V. , Finér Leena , Fischer Markus , Fletcher Christine , Fridman Jonas , Frizzera Lorenzo , Gamarra Javier G. P. , Gianelle Damiano , Glick Henry B. , Harris David J. , Hector Andrew , Hemp Andreas , Hengeveld Geerten , Hérault Bruno , Herbohn John L. , Herold Martin , Hillers Annika , Honorio Coronado Eurídice N. , Hui Cang , Ibanez Thomas , Iêda Amaral , Imai Nobuo , Jagodziński Andrzej M. , Jaroszewicz Bogdan , Johannsen Vivian Kvist , Joly Carlos A. , Jucker Tommaso , Jung Ilbin , Karminov Viktor , Kartawinata Kuswata , Kearsley Elizabeth , Kenfack David , Kennard Deborah K. , Kepfer-Rojas Sebastian , Keppel Gunnar , Khan Mohammed Latif , Killeen Timothy J. , Kim Hyun Seok , Kitayama Kanehiro , Köhl Michael , Korjus Henn , Kraxner Florian , Laarmann Diana , Lang Mait , Lewis Simon L. , Lu Huicui , Lukina Natalia V. , Maitner Brian S. , Malhi Yadvinder , Marcon Eric , Marimon Beatriz Schwantes , Marimon-Junior Ben Hur , Marshall Andrew R. , Martin Emanuel H. , Kucher Dmitry , Meave Jorge A. , Melo-Cruz Omar , Mendoza Casimiro , Merow Cory , Mendoza Abel Monteagudo , Moreno Vanessa S. , Mukul Sharif A. , Mundhenk Philip , Nava-Miranda María Guadalupe , Neill David , Neldner Victor J. , Nevenic Radovan V. , Ngugi Michael R. , Niklaus Pascal A. , Oleksyn Jacek , Ontikov Petr , Ortiz-Malavasi Edgar , Pan Yude , Paquette Alain , Parada-Gutierrez Alexander , Parfenova Elena I. , Park Minjee , Parren Marc , Parthasarathy Narayanaswamy , Peri Pablo L. , Pfautsch Sebastian , Phillips Oliver L. , Picard Nicolas , Piedade Maria Teresa T. F. , Piotto Daniel , Pitman Nigel C. A. , Polo Irina , Poorter Lourens , Poulsen Axel D. , Poulsen John R. , Pretzsch Hans , Arevalo Freddy Ramirez , Restrepo-Correa Zorayda , Rodeghiero Mirco , Rolim Samir G. , Roopsind Anand , Rovero Francesco , Rutishauser Ervan , Saikia Purabi , Salas-Eljatib Christian , Saner Philippe , Schall Peter , Schelhaas Mart-Jan , Schepaschenko Dmitry , Scherer-Lorenzen Michael , Schmid Bernhard , Schöngart Jochen , Searle Eric B. , Seben Vladimír , Serra-Diaz Josep M. , Sheil Douglas , Shvidenko Anatoly Z. , Silva-Espejo Javier E. , Silveira Marcos , Singh James , Sist Plinio , Slik Ferry , Sonké Bonaventure , Souza Alexandre F. , Miscicki Stanislaw , Stereńczak Krzysztof J. , Svenning Jens-Christian , Svoboda Miroslav , Swanepoel Ben , Targhetta Natalia , Tchebakova Nadja , ter Steege Hans , Thomas Raquel , Tikhonova Elena , Umunay Peter M. , Usoltsev Vladimir A. , Valencia Renato , Valladares Fernando , van der Plas Fons , Van Do Tran , van Nuland Michael E. , Vasquez Rodolfo M. , Verbeeck Hans , Viana Helder , Vibrans Alexander C. , Vieira Simone , von Gadow Klaus , Wang Hua-Feng , Watson James V. , Werner Gijsbert D. A. , Westerlund Bertil , Wiser Susan K. , Wittmann Florian , Woell Hannsjoerg , Wortel Verginia , Zagt Roderik , Zawiła-Niedźwiecki Tomasz , Zhang Chunyu , Zhao Xiuhai , Zhou Mo , Zhu Zhi-Xin , Zo-Bi Irie C. , Crowther Thomas W. 
Published: May 2024

The emergence of alternative stable states in forest systems has significant implications for the functioning and structure of the terrestrial biosphere, yet empirical evidence remains scarce. Here, we combine global forest biodiversity observations and simulations to test for alternative stable states in the presence of evergreen and deciduous forest types. We reveal a bimodal distribution of forest leaf types across temperate regions of the Northern Hemisphere that cannot be explained by the environment alone, suggesting signatures of alternative forest states. Moreover, we empirically demonstrate the existence of positive feedbacks in tree growth, recruitment and mortality, with trees having 4–43% higher growth rates, 14–17% higher survival rates and 4–7 times higher recruitment rates when they are surrounded by trees of their own leaf type. Simulations show that the observed positive feedbacks are necessary and sufficient to generate alternative forest states, which also lead to dependency on history (hysteresis) during ecosystem transition from evergreen to deciduous forests and vice versa. We identify hotspots of bistable forest types in evergreen-deciduous ecotones, which are likely driven by soil-related positive feedbacks. These findings are integral to predicting the distribution of forest biomes, and aid to our understanding of biodiversity, carbon turnover, and terrestrial climate feedbacks.