As climates change, species with locally adapted populations may be particularly vulnerable as specialization narrows the range of conditions under which populations can persist. Populations adapted to local climate as well as other site‐specific characteristics like soils present challenges for inferring how changing climates affect fitness, as climatic and nonclimatic variables that constitute local conditions decouple. We conducted two transplant experiments involving American ginseng to test how climatic conditions affect performance while controlling for effects of other site characteristics. We first out‐planted populations from differing elevations to gardens arrayed along an elevation/climate gradient. We also grew maternal plants under temperatures corresponding to home‐site and future conditions (16.4–22.4°C), transplanting resultant progeny to two home‐sites at different elevations (400 m, 800 m). Source populations responded idiosyncratically to elevation reflecting how nonclimatic site characteristics strongly affected plant fitness. Germination rates declined for seeds from maternal plants exposed to warmer temperatures, which compounded with diminished seed production of maternal plants, suggested that population growth may decline rapidly as warm years become hotter and more frequent. Controlling for maternal temperature effects provided evidence that plants are adapted to home‐site conditions, both climatic and nonclimatic, with population growth rates for out‐planted populations ranging from below population replacement levels (
With ongoing climate change, populations are expected to exhibit shifts in demographic performance that will alter where a species can persist. This presents unique challenges for managing plant populations and may require ongoing interventions, including in situ management or introduction into new locations. However, few studies have examined how climate change may affect plant demographic performance for a suite of species, or how effective management actions could be in mitigating climate change effects. Over the course of two experiments spanning 6 yr and four sites across a latitudinal gradient in the Pacific Northwest, United States, we manipulated temperature, precipitation, and disturbance intensity, and quantified effects on the demography of eight native annual prairie species. Each year we planted seeds and monitored germination, survival, and reproduction. We found that disturbance strongly influenced demographic performance and that seven of the eight species had increasingly poor performance with warmer conditions. Across species and sites, we observed 11% recruitment (the proportion of seeds planted that survived to reproduction) following high disturbance, but just 3.9% and 2.3% under intermediate and low disturbance, respectively. Moreover, mean seed production following high disturbance was often more than tenfold greater than under intermediate and low disturbance. Importantly, most species exhibited precipitous declines in their population growth rates (λ) under warmer‐than‐ambient experimental conditions and may require more frequent disturbance intervention to sustain populations.
- Award ID(s):
- 1753954
- NSF-PAR ID:
- 10444140
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Ecology
- Volume:
- 102
- Issue:
- 10
- ISSN:
- 0012-9658
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract λ = 0.58) to well above (λ = 1.33). Evidence of local adaptation to climatic and nonclimatic environmental components, in combination with negative fitness impacts of warming climates on offspring via maternal effects, suggests that changing climate may imperil ginseng and other similar understory species. -
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Abstract During the “decade on restoration,” we must understand how to reliably re‐establish native plant populations. When establishing populations through seed addition, practitioners often prioritize obtaining seed from locations geographically near the restoration site (i.e. “local seed sourcing”). They are assumed to be under similar environmental conditions to the restoration site and should establish more robust plant populations and preserve local biotic interactions better than seeds sourced from further away. However, this assumption remains virtually untested in realistic restoration settings and the importance of seed sourcing, relative to other factors such as seeding rate and management regimes, is unclear.
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Overall, these results support that seed sourcing decisions did not impact plant establishment or abundance in our system. However, using less‐local seed sources may alter flowering phenology.
Our results suggest that tallgrass prairie restoration efforts should prioritize higher seeding rates, post‐seeding management, and might expand the region seed sources are considered “local”, though this may impact flowering phenology. Future research leveraging native seed producer records can help answer critical questions about restoration seed sourcing.
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Summary Plant phenological responses to global warming are well studied. However, while many locations are experiencing increased temperatures, some locations are experiencing climate cooling. Little work has been conducted to understand plant phenological responses to cooling trends, much less the combined effects of cooling and other factors, such as changing precipitation. Furthermore, studies based on herbarium specimens have been instrumental in demonstrating plant responses to global warming; but to our knowledge, herbarium records have not been used to investigate responses to cooling.
We collected data from 98 years of herbarium records to evaluate whether the reproductive phenology (flowering/fruiting) of an annual mustard, cedar gladecress (
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Counter to expectations from global warming studies, our work demonstrates that climate cooling and greater rainfall can result in earlier plant reproductive phenology, potentially due to asymmetric selection for early flowering. Future studies may need to consider climate cooling along with other global change factors to fully explain changes in plant phenology. Our understanding of plant responses to climate cooling can be enhanced through additional herbarium‐based research.
