News & Publications

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.

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.

In places where spring has sprung, how how often have we seen a spring like this one? The USA-NPN's spring leaf out shines light on where leaf out of early season plants has occurred across the country. In the map, darker colors represent springs that are unusually early or late in the long-term record. Gray indicates an average spring.

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.

Punxsutawney Phil predicts an early spring this year. Our map of accumulated growing degree days shows he may be right, for parts of the country anyway. See what Nature's Notebook observers are already reporting on plants and animals across the country.

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.

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.