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Wang N, Song M, Zhang Y, Liu X, Wu P, Qi L, Song H, Du N, Wang H, Zheng P, Wang R. Physiological responses of Quercus acutissima and Quercus rubra seedlings to drought and defoliation treatments. TREE PHYSIOLOGY 2023; 43:737-750. [PMID: 36708029 DOI: 10.1093/treephys/tpad005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 12/27/2022] [Accepted: 01/20/2023] [Indexed: 05/13/2023]
Abstract
Ongoing global climate change is increasing the risk of drought stress in some areas, which may compromise forest health. Such drought events also increase outbreaks of insect herbivores, resulting in plant defoliation. Interactions between drought and defoliation are poorly understood. In a greenhouse experiment, we selected a native species, Quercus acutissima Carr. and an alien species, Quercus rubra L. to explore their physiological responses to drought and defoliation treatments. After the treatments, we determined the seedlings' physiological responses on Days 10 and 60. Our results showed that the defoliation treatment accelerated the carbon reserve consumption of plants under drought stress and inhibited the growth of both seedling types. Under the drought condition, Q. rubra maintained normal stem-specific hydraulic conductivity and normal growth parameters during the early stage of stress, whereas Q. acutissima used less water and grew more slowly during the experiment. Sixty days after defoliation treatment, the stem starch concentration of Q. acutissima was higher than that of the control group, but the stem biomass was lower. This indicates that Q. acutissima adopted a 'slow strategy' after stress, and more resources were used for storage rather than growth, which was conducive to the ability of these seedlings to resist recurrent biotic attack. Thus, Q. acutissima may be more tolerant to drought and defoliation than Q. rubra. The resource acquisition strategies of Quercus in this study suggest that the native Quercus species may be more successful at a long-term resource-poor site than the alien Quercus species.
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Affiliation(s)
- Ning Wang
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Meixia Song
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Yang Zhang
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Xiao Liu
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Pan Wu
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Luyu Qi
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Huijia Song
- Beijing Museum of Natural History, 126 Tianqiao South Street, Beijing 100050, China
| | - Ning Du
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Hui Wang
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Peiming Zheng
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Renqing Wang
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, 72 Binhai Road, Qingdao 266237, China
- Qingdao Forest Ecology Research Station of National Forestry and Grassland Administration, Shandong University, 72 Binhai Road, Qingdao 266237, China
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Topographic, soil, and climate drivers of drought sensitivity in forests and shrublands of the Pacific Northwest, USA. Sci Rep 2020; 10:18486. [PMID: 33116196 PMCID: PMC7595234 DOI: 10.1038/s41598-020-75273-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 10/13/2020] [Indexed: 11/30/2022] Open
Abstract
Climate change is anticipated to increase the frequency and intensity of droughts, with major impacts to ecosystems globally. Broad-scale assessments of vegetation responses to drought are needed to anticipate, manage, and potentially mitigate climate-change effects on ecosystems. We quantified the drought sensitivity of vegetation in the Pacific Northwest, USA, as the percent reduction in vegetation greenness under droughts relative to baseline moisture conditions. At a regional scale, shrub-steppe ecosystems—with drier climates and lower biomass—showed greater drought sensitivity than conifer forests. However, variability in drought sensitivity was considerable within biomes and within ecosystems and was mediated by landscape topography, climate, and soil characteristics. Drought sensitivity was generally greater in areas with higher elevation, drier climate, and greater soil bulk density. Ecosystems with high drought sensitivity included dry forests along ecotones to shrublands, Rocky Mountain subalpine forests, and cold upland sagebrush communities. In forests, valley bottoms and areas with low soil bulk density and high soil available water capacity showed reduced drought sensitivity, suggesting their potential as drought refugia. These regional-scale drought-sensitivity patterns discerned from remote sensing can complement plot-scale studies of plant physiological responses to drought to help inform climate-adaptation planning as drought conditions intensify.
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Ramirez AR, De Guzman ME, Dawson TE, Ackerly DD. Plant hydraulic traits reveal islands as refugia from worsening drought. CONSERVATION PHYSIOLOGY 2020; 8:coz115. [PMID: 32015878 PMCID: PMC6988607 DOI: 10.1093/conphys/coz115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 12/05/2019] [Accepted: 12/31/2019] [Indexed: 05/14/2023]
Abstract
Relatively mesic environments within arid regions may be important conservation targets as 'climate change refugia' for species persistence in the face of worsening drought conditions. Semi-arid southern California and the relatively mesic environments of California's Channel Islands provide a model system for examining drought responses of plants in potential climate change refugia. Most methods for detecting refugia are focused on 'exposure' of organisms to certain abiotic conditions, which fail to assess how local adaptation or acclimation of plant traits (i.e. 'sensitivity') contribute to or offset the benefits of reduced exposure. Here, we use a comparative plant hydraulics approach to characterize the vulnerability of plants to drought, providing a framework for identifying the locations and trait patterns that underlie functioning climate change refugia. Seasonal water relations, xylem hydraulic traits and remotely sensed vegetation indices of matched island and mainland field sites were used to compare the response of native plants from contrasting island and mainland sites to hotter droughts in the early 21st century. Island plants experienced more favorable water relations and resilience to recent drought. However, island plants displayed low plasticity/adaptation of hydraulic traits to local conditions, which indicates that relatively conserved traits of island plants underlie greater hydraulic safety and localized buffering from regional drought conditions. Our results provide an explanation for how California's Channel Islands function as a regional climate refugia during past and current climate change and demonstrate a physiology-based approach for detecting potential climate change refugia in other systems.
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Affiliation(s)
- Aaron R Ramirez
- Department of Integrative Biology, University of California, 3040 Valley Life Sciences Building #3140 Berkeley CA 94720-3200, USA
- Department of Biology & Environmental Studies, Reed College, Portland, 33203 Southeast Woodstock Blvd., Portland, Oregon 97202-8199, USA
- Corresponding author: Department of Biology & Environmental Studies, Reed College, Portland, 33203 Southeast Woodstock Blvd., Portland, Oregon 97202-8199, USA. Tel: +(503) 517-4101.
| | - Mark E De Guzman
- Department of Biology & Environmental Studies, Reed College, Portland, 33203 Southeast Woodstock Blvd., Portland, Oregon 97202-8199, USA
- Department of Botany & Plant Sciences, University of California, Riverside, 900 University Ave., Riverside CA 92521, USA
| | - Todd E Dawson
- Department of Integrative Biology, University of California, 3040 Valley Life Sciences Building #3140 Berkeley CA 94720-3200, USA
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall #3114, Berkeley, CA 94720-3114, USA
| | - David D Ackerly
- Department of Integrative Biology, University of California, 3040 Valley Life Sciences Building #3140 Berkeley CA 94720-3200, USA
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall #3114, Berkeley, CA 94720-3114, USA
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