Climate change is predicted to affect the survival, reproduction and range distribution of many plant species. Many studies have addressed climate change, but few have focused their attention on the effects it will have on native prairies in the Pacific Northwest. Heating of Prairie Systems (HOPS) is a multi-University study aimed at understanding how prairie species react to a changing climate. This student-created website offers information about the HOPS project, the Bridgham lab, the researchers and their experiment.

Climate Change in the Pacific Northwest

Photo by: Justin Culman

Climate change is predicted to alter our environment through several changes in weather patterns.An increase in the temperature globally, as well as more frequent and severe weather events, are some of the impacts that we can expect. Climate change may cause higher variability in precipitation and cycling between severe drought and flooding throughout the year. In the Pacific Northwest, there will be higher seasonal variation in precipitation leading to both increase winter precipitation and summer droughts [1]. In the past century, average temperatures in Oregon have increased by  0.5-1.5ºC with annual precipitation increasing by 10% [1]. Additionally, temperature is projected to increase by 3°C to 6°C by the end of the century, leading to more frequent periods of drought [1].

A key challenge in biology is understanding how climate change will interact with other perturbations, such as human land use and invasive species encroachment, to impact biodiversity through changes in species range distributions. There is abundant evidence that many species have shifted their ranges in the past 30 years concurrent with recent climate change. But will species be able to adapt to the new climate or will they keep shifting their ranges. To understand these questions it is important to have both a strong theoretical framework as well as empirical observations when considering possible future shifts of species. Moreover, dispersal has not been incorporated in models of species range shifts to date except in very rudimentary ways, but dispersal may limit many species from responding to climate change, especially in today’s fragmented landscapes.

Why Study Pacific Northwest Prairies?

Prairies and oak savannas were once major ecosystems in the interior valleys of Oregon and Washington. However, changes in land use, and the resulting degradation, have lead to a reduction in prairie coverage. In some areas coverage has reduced to 1% their historic extent [1; 2]. Anthropogenic climate change further threatens prairies in the Pacific Northwest.

Pacific Northwest prairies are endangered ecosystems that contain a large number of plant species with high fidelity to this habitat. Many of these species have latitudinal range limits that lie throughout Northern California to Southern Washington. The few remaining high-quality prairies harbor a number of sensitive, rare, and endangered plant species that may be put at higher risk of extinction due to climate change. This situation is also typical of many other habitats that contain rare and/or endemic species. To better understand how future climate change will affect the biological timing (known as phenology) and range distribution of native plant species the HOPS project is experimentally manipulating temperature and precipitation in three upland prairie sites along a natural climate gradient from southwestern Oregon to central-western Washington.

Broader Implications

 Shifts in phenological timing could lead to asynchronicities between prairie plant species and their pollinators. If plants flower when pollinators aren’t present it could lead to lower rates of pollination for the plants, and a reduction in available food sources for the pollinators. These disruptions of species interactions could potentially lead to a reduction in species fitness. Furthermore, shifts in plant phenology and range distribution could allow invasive species to move in to previously occupied niches. The ways in which plants species react to a changing climate could potentially lead to very different prairie ecosystems then we have today. A greater understanding of potential impacts of climate change on prairies will help land managers conserve and restore these important ecosystems.

Photo by: Lauren Hendricks

1. Bachelet D, Johnson BR, Bridgham SD, Dunn PV, Anderson HE, Rogers BM. 2011. Climate Change Impacts on Western Pacific Northwest Prairies and Savannas. Northwest Science 85:411–429.

2. Christy JA, Alverson ER. 2011. Historical Vegetation of the Willamette Valley, Oregon, circa 1850. Northwest Science 85:93–107.