Nature’s Notebook

Connecting People with Nature to Benefit Our Changing Planet

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

Nature’s Notebook observations help to manage invasive buffelgrass

Buffelgrass, an invasive perennial grass that responds well to fire and outcompetes natives, threatens to transform the current Sonoran desert landscape. Managers need to treat buffelgrass with herbicides when the plant is at least 50% green. The authors of a new study in the journal Remote Sensing found that buffelgrass responds quickly to rain, with plant green up occurring twice as fast in areas with buffelgrass than areas with mostly native vegetation. This information will help managers know when to get out to spray buffelgrass. Studies such as this, which integrate on-the-ground observations of phenology with satellite data, demonstrate the power of multiple data sources to inform management activities.

Nature’s Notebook observations validate remotely-sensed data

While there is great potential in linking data collected by observers on the ground and data collected by remote satellites, few studies have successfully combined these two types of data. Researchers from the Appalachian Laboratory at the University of Maryland Center for Environmental Science compared observations of leaf phenology collected through the Nature’s Notebook PopClock campaign to continental-scale satellite imagery collected by the Moderate Resolution Imaging Spectrometer (MODIS). They implemented three quality control procedures that resulted in a high correlation between the two datasets (r2 = 0.67). Being able to more easily combine citizen science and remotely-sensed data will give scientists a large amount of information over a range of geographic scales, to better understand the response of forest plants to future changes in climate.  

Kodiak brown bears are synced with the salmon red wave

Authors of a study from the University of Montana, University of Wyoming, and US Fish and Wildlife Service investigated how well Kodiak brown bears track spawning salmon. Bears greatly depend on this salmon resource, which is threatened by habitat fragmentation and low diversity of spawning phenology that can be introduced by hatchery stocks. 

Finer resolution models provide local predictions of leaf-out in California oaks

Researchers from Princeton, Chapman University, and UCLA developed models of valley oak leaf-out under past and future climate scenarios to test how changing the spatial scale of these models affects leaf-out. The authors used data collected by the California Phenology Project, which began in 2010 and is part of the USA National Phenology Network, to validate their models of valley oak leaf-out before downscaling the models to create local predictions of leaf-out.

Climate change means snowshoe hares stand out like lightbulbs against a snowless background

Researchers from North Carolina State University and the University of Montana found weekly survival decreases of up to 7% for hares that had coat color that was mismatched with their surroundings, making them stand out like lightbulbs on a dark background. The researchers used models to predict how the population of hares is likely to change given the survival rates they observed. Under future climate change scenarios, they project that hare populations could decrease by up to 23% by the end of the century. 

Herbarium records provide insight to flowering phenology in the Southeast U.S.

Flowering in sub-tropical regions is thought to be more sensitive to temperature than precipitation, though this has not been widely studied. The authors of this study looked at herbarium records of over 1700 native herbaceous flowering plant species from South Carolina from 1951 to 2009. They found plants with early spring, late spring, and summer flowering were all responsive to increasing February and March temperatures. 

Warblers shift breeding time to maximize food resources

Animals may be adversely affected if they are not able to match shifts in timing of their food or other resources. The authors of a new study found black-throated blue warblers have a varied diet and ability to shift the timing of their nesting, which allows them to be less susceptible to trophic mismatch after arrival at their breeding grounds.

Future springs may arrive three weeks earlier across the US

The earlier springs seen in recent decades may become a permanent change. Researchers at UW - Madison predict that by the end of this century, spring will appear approximately three weeks earlier across the continental U.S. False springs are also likely to increase in the Great Plains and portions of the Midwest. 

Do migrating geese surf the Green wave?

An international team of scientists found that Barnacle Geese overtake the green wave, first arriving at the southernmost stopover sites along their migration pathway to fatten up on the peak plant biomass, then arriving at their northern breeding grounds at the local start of spring. This allows growing goslings the highest amount of nutrients and thus the best chance at survival.

Increasing winter temperatures and rainfall cause shifts in phenology in four California species

Researchers from the California Phenology Project compared observations of leaf budburst, flowering, fruiting and leaf drop with climate variables such as temperature and rainfall. The authors found that in all four species, at least one phenophase responded to higher winter low temperatures with delayed onset. Generally, precipitation strongly influenced leaf phenology, while both precipitation and temperature were important for flower and fruit phenology.