News & Publications

A new study by researchers at the USA-National Phenology Network, US Geological Survey, University of Arizona, Schoodic Institute, Cornell University and the University of Wisconsin-Milwaukee shows that climate change is already happening on public lands. The authors found that spring is advancing in 76% of the 276 Parks studied, and 53% of parks are experiencing extreme early springs that exceed 95% of historical conditions. Better knowledge of warming trends will help Parks to treat invasive species, operate visitor facilities, and schedule popular climate-related events, such as flower festivals and fall leaf-viewing.

The “false spring” of 2012 was the earliest in an over 100 year record, and resulted in large-scale agricultural losses. To find out if these types of springs will become more common in the future, researchers used new climate change simulation models, including the USA-NPN’s Spring Indices, to distinguish natural climate fluctuations from longer-term trends. They found that by mid-century, we could see springs like that of 2012 as often as one out of every three years. They also found last freeze dates may not change at the same rate, resulting in more large-scale tissue damage and agricultural losses.

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.

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.

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.

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.

Plants rely on their roots for delivery of water and nutrients, not to mention for the structure that anchors them to the earth. Just as new leaves or needles grow in the springtime, roots also have a period of growth, or production. To better understand the relationship between leaf and root production, the authors of this study evaluated patterns in the timing of leaf and root phenology in deciduous and coniferous trees.

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.

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.