News & Publications

In this study, a research team evaluated eight approaches to identifying the dates of the starts and ends of the growing season to MODIS imagery across United States. They compared the estimates of start and end of season with phenology observations contributed to Nature’s Notebook. The different approaches to identifying the start and end of the season showed a great deal of variability in the dates returned. The date identified as the start of the season at a location varied by as much as 50 days between two approaches. The authors of this study emphasize the importance of ground-based observations of phenology, such as those contributed to Nature’s Notebook, in interpreting imagery collected by remote instruments such as those borne on satellites.

Accounting for the fact that species respond differently to the same amount of warmth in different parts of their range presents a challenge for predicting phenological events like leaf-out. The authors of a new study developed a novel approach for incorporating this phenomenon into phenology models. They then incorporated this approach into models of budbreak for 14 widely distributed tree species. This study was only possible due to the large amount of data collected by Nature’s Notebook observers across a broad area. Incorporating this information will lead to more accurate, geographically-relevant forecasts for management of these species.

We have a decade of data on over a thousand species – thanks to your efforts! We can start to answer big picture questions, as this study did, finding that leaf out in spring comes earlier in response to longer days and spring warmth, and is delayed by freezes and lack of winter cold. Delayed phenology can be a good thing, protecting plants from false springs - or have a negative effect, by limiting the time plants have to take advantage of the growing season.

Managers have traditionally used dogwood blooms as an indicator of when to set out traps, recognizing that dogwood flowering tended to coincide with the beetle’s springtime dispersal. Using observations contributed to Nature’s Notebook, researchers determined that dogwood flowering is not presently a strong indicator of southern pine beetle spring emergence, and the reason for this might be recent changes in climate conditions.

Authors of a new study published in the journal Nature sought to understand how human-caused light and noise pollution might pose additional challenges to birds impacted by climate change. They found that light pollution caused birds to nest a month earlier in open environments and 18 days earlier in forested environments. This advance in timing allowed the birds to catch up to earlier spring onset and availability of food, resulting in better nesting success. Managers can use this information to know which species are at greater risk from climate change impacts, and prioritize habitat for vulnerable species. Communities can also use this information to assess their own light and sound footprints.

Invasive, non-native shrubs frequently leaf out earlier in the spring and hold onto leaves later in the fall than natives, out-competing native plants and shading the forest floor at times when other species depend on the sunlight. To better understand how this phenomenon of Extended Leaf Phenology in invasive plants plays out at a regional scale, Maynard-Bean and colleagues used data collected by Nature's Notebook participants to document differences in leaf phenology between native and invasive shrubs. The authors found that the leaf period was up to 77 days longer for invasive species compared to natives. Better knowledge of how invasive shrubs negatively impact natives can help stem the purposeful spread of these plants by humans and protect native species and their ecosystems.

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.

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.

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.

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!