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Knapp PA, Soulé PT, Mitchell TJ, Catherwood AA, Lewis HS. Increasing radial growth in old-growth high-elevation conifers in Southern California, USA, during the exceptional "hot drought" of 2000-2020. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2024; 68:743-748. [PMID: 38214750 DOI: 10.1007/s00484-024-02619-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 12/15/2023] [Accepted: 01/04/2024] [Indexed: 01/13/2024]
Abstract
Hot droughts, droughts attributed to below-average precipitation and exceptional warmth, are increasingly common in the twenty-first century, yet little is known about their effect on coniferous tree growth because of their historical rarity. In much of the American West, including California, radial tree growth is principally driven by precipitation, and narrow ring widths are typically associated with either drier or drought conditions. However, for species growing at high elevations (e.g., Larix lyalli, Pinus albicaulis), growth can be closely aligned with above-average temperatures with maximum growth coinciding with meteorological drought, suggesting that the growth effects of drought span from adverse to beneficial depending on location. Here, we compare radial growth responses of three high-elevation old-growth pines (Pinus jeffreyi, P. lambertiana, and P. contorta) growing in the San Jacinto Mountains, California, during a twenty-first-century hot drought (2000-2020) largely caused by exceptional warmth and a twentieth-century drought (1959-1966) principally driven by precipitation deficits. Mean radial growth during the hot drought was 12% above average while 18% below average during the mid-century drought illustrating that the consequences of environmental stress exhibit spatiotemporal variability. We conclude that the effects of hot droughts on tree growth in high-elevation forests may produce responses different than what is commonly associated with extended dry periods for much of western North America's forested lands at lower elevational ranges and likely applies to other mountainous regions (e.g., Mediterranean Europe) defined by summer-dry conditions. Thus, the climatological/biological interactions discovered in Southern California may offer clues to the unique nature of high-elevation forested ecosystems globally.
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Affiliation(s)
- Paul A Knapp
- Carolina Tree-Ring Science Laboratory, Department of Geography, Environment and Sustainability, University of North Carolina Greensboro, Greensboro, NC, USA.
| | - Peter T Soulé
- Appalachian Tree Ring Lab, Department of Geography and Planning, Appalachian State University, Boone, NC, USA
| | - Tyler J Mitchell
- Carolina Tree-Ring Science Laboratory, Department of Geography, Environment and Sustainability, University of North Carolina Greensboro, Greensboro, NC, USA
| | - Avery A Catherwood
- Carolina Tree-Ring Science Laboratory, Department of Geography, Environment and Sustainability, University of North Carolina Greensboro, Greensboro, NC, USA
| | - Hunter S Lewis
- Carolina Tree-Ring Science Laboratory, Department of Geography, Environment and Sustainability, University of North Carolina Greensboro, Greensboro, NC, USA
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Ma F, Yan Y, Svenning JC, Quan Q, Peng J, Zhang R, Wang J, Tian D, Zhou Q, Niu S. Opposing effects of warming on the stability of above- and belowground productivity in facing an extreme drought event. Ecology 2024; 105:e4193. [PMID: 37882140 DOI: 10.1002/ecy.4193] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/05/2023] [Accepted: 09/18/2023] [Indexed: 10/27/2023]
Abstract
Climate warming, often accompanied by extreme drought events, could have profound effects on both plant community structure and ecosystem functioning. However, how warming interacts with extreme drought to affect community- and ecosystem-level stability remains a largely open question. Using data from a manipulative experiment with three warming treatments in an alpine meadow that experienced one extreme drought event, we investigated how warming modulates resistance and recovery of community structural and ecosystem functional stability in facing with extreme drought. We found warming decreased resistance and recovery of aboveground net primary productivity (ANPP) and structural resistance but increased resistance and recovery of belowground net primary productivity (BNPP), overall net primary productivity (NPP), and structural recovery. The findings highlight the importance of jointly considering above- and belowground processes when evaluating ecosystem stability under global warming and extreme climate events. The stability of dominant species, rather than species richness and species asynchrony, was identified as a key predictor of ecosystem functional resistance and recovery, except for BNPP recovery. In addition, structural resistance of common species contributed strongly to the resistance changes in BNPP and NPP. Importantly, community structural resistance and recovery dominated the resistance and recovery of BNPP and NPP, but not for ANPP, suggesting the different mechanisms underlie the maintenance of stability of above- versus belowground productivity. This study is among the first to explain that warming modulates ecosystem stability in the face of extreme drought and lay stress on the need to investigate ecological stability at the community level for a more mechanistic understanding of ecosystem stability in response to climate extremes.
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Affiliation(s)
- Fangfang Ma
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Yingjie Yan
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- Department of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Jens-Christian Svenning
- Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) and Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Quan Quan
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Jinlong Peng
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- Department of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Ruiyang Zhang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Jinsong Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Dashuan Tian
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Qingping Zhou
- Institute of Qinghai-Tibetan Plateau, Southwest University for Nationalities, Chengdu, China
| | - Shuli Niu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- Department of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
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