The relative importance of global versus local environmental factors for growth and thus carbon uptake of the bryophyte genus We measured length growth and net primary production (NPP) of two abundant Variation in growth was large, but similar within and between peatlands. Length growth showed a stronger response to predictors than NPP. Moreover, the smaller and denser
This content will become publicly available on November 20, 2024
Climate models predict that everwet western Amazonian forests will face warmer and wetter atmospheric conditions, and increased cloud cover. It remains unclear how these changes will impact plant reproductive performance, such as flowering, which plays a central role in sustaining food webs and forest regeneration. Warmer and wetter nights may cause reduced flower production, via increased dark respiration rates or alteration in the reliability of flowering cue‐based processes. Additionally, more persistent cloud cover should reduce the amounts of solar irradiance, which could limit flower production. We tested whether interannual variation in flower production has changed in response to fluctuations in irradiance, rainfall, temperature, and relative humidity over 18 yrs in an everwet forest in Ecuador. Analyses of 184 plant species showed that flower production declined as nighttime temperature and relative humidity increased, suggesting that warmer nights and greater atmospheric water saturation negatively impacted reproduction. Species varied in their flowering responses to climatic variables but this variation was not explained by life form or phylogeny. Our results shed light on how plant communities will respond to climatic changes in this everwet region, in which the impacts of these changes have been poorly studied compared with more seasonal Neotropical areas.
- Award ID(s):
- 1754668
- NSF-PAR ID:
- 10475100
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 241
- Issue:
- 3
- ISSN:
- 0028-646X
- Format(s):
- Medium: X Size: p. 1035-1046
- Size(s):
- p. 1035-1046
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract Sphagnum— the main peat‐former and ecosystem engineer in northern peatlands—remains unclear.Sphagnum species across 99 Holarctic peatlands. We tested the importance of previously proposed abiotic and biotic drivers for peatland carbon uptake (climate, N deposition, water table depth and vascular plant cover) on these two responses. Employing structural equation models (SEMs), we explored both indirect and direct effects of drivers onSphagnum growth.Sphagnum fuscum growing on hummocks had weaker responses to climatic variation than the larger and looserSphagnum magellanicum growing in the wetter conditions. Growth decreased with increasing vascular plant cover within a site. Between sites, precipitation and temperature increased growth forS. magellanicum . The SEMs indicate that indirect effects are important. For example, vascular plant cover increased with a deeper water table, increased nitrogen deposition, precipitation and temperature. These factors also influencedSphagnum growth indirectly by affecting moss shoot density.Synthesis . Our results imply that in a warmer climate,S. magellanicum will increase length growth as long as precipitation is not reduced, whileS. fuscum is more resistant to decreased precipitation, but also less able to take advantage of increased precipitation and temperature. Such species‐specific sensitivity to climate may affect competitive outcomes in a changing environment, and potentially the future carbon sink function of peatlands. -
Summary Urbanization can affect the timing of plant reproduction (i.e. flowering and fruiting) and associated ecosystem processes. However, our knowledge of how plant phenology responds to urbanization and its associated environmental changes is limited.
Herbaria represent an important, but underutilized source of data for investigating this question. We harnessed phenological data from herbarium specimens representing 200 plant species collected across 120 yr from the eastern US to investigate the spatiotemporal effects of urbanization on flowering and fruiting phenology and frost risk (i.e. time between the last frost date and flowering).
Effects of urbanization on plant reproductive phenology varied significantly in direction and magnitude across species ranges. Increased urbanization led to earlier flowering in colder and wetter regions and delayed fruiting in regions with wetter spring conditions. Frost risk was elevated with increased urbanization in regions with colder and wetter spring conditions.
Our study demonstrates that predictions of phenological change and its associated impacts must account for both climatic and human effects, which are context dependent and do not necessarily coincide. We must move beyond phenological models that only incorporate temperature variables and consider multiple environmental factors and their interactions when estimating plant phenology, especially at larger spatial and taxonomic scales.
-
Societal Impact Statement Networks of digitized herbarium records are rich resources for understanding plant responses to climate change. While the climate is warming globally, some localities are experiencing climate cooling, the effects of which are poorly understood. Our herbarium‐based study of a geographically restricted species shows that the timing of reproduction can shift earlier as the climate becomes cooler and wetter. Local variation in climate change may be a key factor driving the high variability of changes observed in plant reproduction and climate cooling should be considered along with other global change drivers. This will help enable accurate predictions for the successful management of climate change effects.
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 (
Leavenworthia stylosa ), has changed as the climate has become cooler and wetter in central Tennessee, USA. Additionally, we conducted two field experiments to assess reproductive consequences of different flowering times.Over the last century, gladecress reproductive phenology has shifted 2.1 days earlier per decade, concurrent with wetter conditions during germination and cooler conditions during reproduction. Field experiments showed that plants with extremely early and moderately early flowering had equivalent reproduction, but these plants had greater reproduction than intermediate‐ and late‐flowering plants.
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.
-
Abstract Pollination is essential to fruit production. How plant diversity and blooming events in and around orchards affect the pollinator community and the plant‐flower‐visitor network in neotropical systems remains largely unknown.
We surveyed the flower visitors in deciduous fruit trees and alternative blooming resources (other crops, hedgerows and weeds) in Colombia across 6 orchards over 12 months. We evaluated whether plant species richness and blooming cover influenced abundance and richness of flower visitors, as well as network‐level connectance and specialization. We also assessed the role of alternative blooming resources for the flower visitors of deciduous fruit trees.
Overall, we found 66 taxa of flower visitors, 35 of which visited deciduous fruit trees. There was a greater abundance of flower visitors when there was higher richness of weedy species and greater blooming cover of deciduous fruit trees. Networks were less connected when there was lower crop and weedy species richness. Finally, flower visitor abundance and specialization increased when there were multiple hedgerow species in bloom with a high blooming cover.
We highlight the importance of maintaining alternative blooming resources in and around the orchards to support deciduous fruit tree pollinators and diversity in the plant flower‐visitor network.
-
Abstract Atmospheric warming heats lakes, but the causes of variation among basins are poorly understood. Here, multi-decadal profiles of water temperatures, trophic state, and local climate from 345 temperate lakes are combined with data on lake geomorphology and watershed characteristics to identify controls of the relative rates of temperature change in water (WT) and air (AT) during summer. We show that differences in local climate (AT, wind speed, humidity, irradiance), land cover (forest, urban, agriculture), geomorphology (elevation, area/depth ratio), and water transparency explain >30% of the difference in rate of lake heating compared to that of the atmosphere. Importantly, the rate of lake heating slows as air warms (
P < 0.001). Clear, cold, and deep lakes, especially at high elevation and in undisturbed catchments, are particularly responsive to changes in atmospheric temperature. We suggest that rates of surface water warming may decline relative to the atmosphere in a warmer future, particularly in sites already experiencing terrestrial development or eutrophication.