Germination and seedling growth of Calluna vulgaris is sensitive to regional climate, heathland succession, and drought
Abstract The coastal heathlands of Northwest Europe are highly valued cultural landscapes, that are critically endangered due to land use and climatic changes, such as increased frequency and severity of drought events. Our study is the first to assess how the germination and early seedling growth o...
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Wiley
2023-07-01
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| Series: | Ecology and Evolution |
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| Online Access: | https://doi.org/10.1002/ece3.10199 |
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| author | Kristine Birkeli Ragnhild Gya Siri Vatsø Haugum Liv Guri Velle Vigdis Vandvik |
| author_facet | Kristine Birkeli Ragnhild Gya Siri Vatsø Haugum Liv Guri Velle Vigdis Vandvik |
| author_sort | Kristine Birkeli |
| collection | DOAJ |
| description | Abstract The coastal heathlands of Northwest Europe are highly valued cultural landscapes, that are critically endangered due to land use and climatic changes, such as increased frequency and severity of drought events. Our study is the first to assess how the germination and early seedling growth of Calluna vulgaris respond to drought. In a factorial design field experiment, we exposed maternal plants to three in‐situ drought treatments (control, 60%, 90% roof coverage), across three successional stages after fire (pioneer, building, mature), and two regions (60°N, 65°N). Seeds from 540 plants within the experiment were, weighed, and exposed to five water potentials, ranging from −0.25 to −1.7 MPa, in a growth chamber experiment. We recorded germination (percentage, rate), seedling growth (above‐ vs. belowground allocation), and seedling functional traits (specific leaf area [SLA], specific root length [SRL]). Overall variation in germination between regions, successional stages, and maternal drought treatments was largely mediated by variation in seed mass. Plants from the northernmost region had higher seed mass and germination percentages. This is indicative of higher investment in seeds, likely linked to the populations' absence of vegetative root sprouting. Seeds from the mature successional stage germinated to lower final percentages than those from earlier successional stages, especially when the maternal plants had been exposed to drought (60% and 90% roof coverage). Exposure to reduced water availability decreased germination percentage and increased the time to 50% germination. Seedlings fully developed in the range −0.25 to −0.7 MPa, with increased root:shoot and lower SRL during reduced water availability, suggesting a resource‐conservative response to drought during the early stages of development. Our results thus suggest a sensitivity to drought during the germination and seedling life‐history stages that may reduce Calluna's ability to re‐establish from seeds as the incidence and severity of droughts are projected to increase under future climates. |
| format | Article |
| id | doaj-art-7b5e1cd90fd64a9cb34cc03390b2ec1c |
| institution | DOAJ |
| issn | 2045-7758 |
| language | English |
| publishDate | 2023-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Ecology and Evolution |
| spelling | doaj-art-7b5e1cd90fd64a9cb34cc03390b2ec1c2025-08-20T02:56:31ZengWileyEcology and Evolution2045-77582023-07-01137n/an/a10.1002/ece3.10199Germination and seedling growth of Calluna vulgaris is sensitive to regional climate, heathland succession, and droughtKristine Birkeli0Ragnhild Gya1Siri Vatsø Haugum2Liv Guri Velle3Vigdis Vandvik4Department of Biological Sciences University of Bergen Bergen NorwayDepartment of Biological Sciences University of Bergen Bergen NorwayDepartment of Biological Sciences University of Bergen Bergen NorwayMøreforsking Ålesund NorwayDepartment of Biological Sciences University of Bergen Bergen NorwayAbstract The coastal heathlands of Northwest Europe are highly valued cultural landscapes, that are critically endangered due to land use and climatic changes, such as increased frequency and severity of drought events. Our study is the first to assess how the germination and early seedling growth of Calluna vulgaris respond to drought. In a factorial design field experiment, we exposed maternal plants to three in‐situ drought treatments (control, 60%, 90% roof coverage), across three successional stages after fire (pioneer, building, mature), and two regions (60°N, 65°N). Seeds from 540 plants within the experiment were, weighed, and exposed to five water potentials, ranging from −0.25 to −1.7 MPa, in a growth chamber experiment. We recorded germination (percentage, rate), seedling growth (above‐ vs. belowground allocation), and seedling functional traits (specific leaf area [SLA], specific root length [SRL]). Overall variation in germination between regions, successional stages, and maternal drought treatments was largely mediated by variation in seed mass. Plants from the northernmost region had higher seed mass and germination percentages. This is indicative of higher investment in seeds, likely linked to the populations' absence of vegetative root sprouting. Seeds from the mature successional stage germinated to lower final percentages than those from earlier successional stages, especially when the maternal plants had been exposed to drought (60% and 90% roof coverage). Exposure to reduced water availability decreased germination percentage and increased the time to 50% germination. Seedlings fully developed in the range −0.25 to −0.7 MPa, with increased root:shoot and lower SRL during reduced water availability, suggesting a resource‐conservative response to drought during the early stages of development. Our results thus suggest a sensitivity to drought during the germination and seedling life‐history stages that may reduce Calluna's ability to re‐establish from seeds as the incidence and severity of droughts are projected to increase under future climates.https://doi.org/10.1002/ece3.10199allocationcoastal heathlandsdrought experimentdwarf‐shrub heathfunctional traitsgermination rate |
| spellingShingle | Kristine Birkeli Ragnhild Gya Siri Vatsø Haugum Liv Guri Velle Vigdis Vandvik Germination and seedling growth of Calluna vulgaris is sensitive to regional climate, heathland succession, and drought Ecology and Evolution allocation coastal heathlands drought experiment dwarf‐shrub heath functional traits germination rate |
| title | Germination and seedling growth of Calluna vulgaris is sensitive to regional climate, heathland succession, and drought |
| title_full | Germination and seedling growth of Calluna vulgaris is sensitive to regional climate, heathland succession, and drought |
| title_fullStr | Germination and seedling growth of Calluna vulgaris is sensitive to regional climate, heathland succession, and drought |
| title_full_unstemmed | Germination and seedling growth of Calluna vulgaris is sensitive to regional climate, heathland succession, and drought |
| title_short | Germination and seedling growth of Calluna vulgaris is sensitive to regional climate, heathland succession, and drought |
| title_sort | germination and seedling growth of calluna vulgaris is sensitive to regional climate heathland succession and drought |
| topic | allocation coastal heathlands drought experiment dwarf‐shrub heath functional traits germination rate |
| url | https://doi.org/10.1002/ece3.10199 |
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