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You can learn more about recent phenology research in the publication summaries below.

Early spring brings higher numbers of asthma-related hospital admissions

In order to see whether the timing of spring onset is associated with rates of asthma-related hospital admissions, a team of researchers looked at hospitalization data, the timing of spring as measured by satellite data, and pollen monitoring data to determine the length of pollen season. They found that early spring was associated with a 17% increase in hospital admissions for asthma, while a late start of spring was associated with a 7% decrease. Researchers can use information about the timing of spring season to anticipate the severity and timing of allergy season, providing personalized early warning systems that may reduce asthma hospitalizations.

Using phenology to improve invasive plant management

In order to better target the timing of control of invasive Vebesina enceliodes, a team of staff and volunteers at Midway Atoll National Wildlife Refuge began collecting phenology data to identify how much time they had in between when the plant starts to grow and when it drops its seeds. After a year of data collection with Nature's Notebook, the team determined the number of days they could allow between treatments and adjusted their schedules accordingly. This study demonstrates the potential for data collected by volunteer scientists to inform ecological restoration.

Where there are flowers, there could be fire

Flowering in chamise, a widely distributed plant in fire-prone chapparal California, is a good indicator of fire risk. Data contributed to Nature’s Notebook helped researchers identify that a critical live fuel moisture threshold is crossed after the plant has flowered but before fruits have developed. Accordingly, managers can readily and inexpensively assess live fuel moisture status in these areas simply by looking at chamise flower and fruit status. This study shows the potential for phenology information from programs like Nature’s Notebook to inform critical management decisions.

Urbanization advances phenology in cold regions but not warm ones

Authors of a new study using Nature's Notebook data found that in cold regions, urbanization leads to earlier leaf-out and flowering in plants. However, in warmer temperate and sub-tropical regions, urbanization delays leafing and flowering. The authors speculate several reasons for this difference, including a lack of winter chilling that some plants require, heat stress, or a greater influence of other aspects of urbanization besides heat. Phenology can serve as the “canary in the coal mine” for climate change impacts on our environment, so keep those Nature’s Notebook observations coming!

Citizen science programs help urban growers manage insects

Urban growers need information about how best to manage pests, for example, knowing when to apply a pesticide to have the least likelihood of impacting a beneficial pollinator. Data resulting from citizen science programs like Nature’s Notebook, iNaturalist, and eButterfly can support urban growers’ efforts to increase the presence of pollinators and other beneficial insects and decrease insect pests. Growers can use these platforms to support insect identification, store their data in a standardized format, compare their data to those from other farms, and predict when pests will be most vulnerable to treatment.

The early fish misses the phytoplankton

The timing of phytoplankton blooms is critical to the survival of fish including haddock, herring, and salmon. The authors looked at the impact of a high-emissions climate warming scenario on two groups of fishes that live in the surface layer of the ocean and spawn in springtime. Fish species that rely on geographic features such as rivers are predicted to change their spawning timing twice as fast as phytoplankton bloom timing, resulting in spawning occurring earlier than phytoplankton bloom across 86% of the area studied. Mismatches in this ecosystem could cause population declines with cascading effects on global carbon cycles.

What puts plants most at risk of late spring freezes?

The number of early springs followed by late freeze events, called false springs, is predicted to increase due to climate change. To determine the likelihood of damage from a late spring freeze in temperate forests, the authors evaluated several datasets that reflect the start of spring including the USA-NPN’s spring leaf index. Many factors play a role in the susceptibility of plants to damage from false springs, including the plant’s life stage, functional group, morphology, and phenological traits such as whether the plant puts on buds early. A clearer understanding of how to estimate the risk of false springs for various species/functional types improves estimates of the future frequency of false springs under different climate change scenarios and can help improve models of species range shifts, carbon budgets and even feedback loops between climate shifts and forest composition.

Integrating herbarium specimens with observed phenology data

Integrating herbarium data with contemporary phenology data requires standardized terminology, definitions, and principles. The authors of a new study in Applications in Plant Sciences describe the Plant Phenology Ontology, an effort to integrate herbarium and field data. They demonstrate the use of this framework by combining herbarium data and observations from Nature’s Notebook to show that in North America, flowering time for black cherry (Prunus serotina) has been steadily accelerating since 1873.

Nature’s Notebook data show shift to earlier milkweed flowering

Nature’s Notebook data were used to evaluate how common milkweed flowering is responding to changes in climate. With each degree of maximum temperature increase, the mean flowering date for milkweed shifted nearly four days earlier. The shift occurred across first, last, and mean flowering dates but did not extend to initial growth or fruit ripening. The shift became more significant over the period of 2011 to 2016. These findings will help managers develop conservation plans for this species and its pollinators.

Overlooked climate factors predict flowering phenology best

Researchers at UC Santa Barbara combined herbarium records with observations contributed by Nature’s Notebook participants to assess the impact of climate variables on timing of flowering in 2,500 species of plants. The authors found that maximum temperature, the number of frost-free days, and the quantity of precipitation as snow were the best predictors of flowering time for both herbarium and observed data. A better understanding of the climate variables that drive flowering phenology can help us anticipate how future changes in climate might impact flowering. 

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