Conservation Science

Protecting Pennsylvania’s Plants and Animals

Climate Change

Climate change is a problem of global proportion and its impacts have begun to alter the world as we know it. For thousands of years Earth’s climate has been relatively stable. Since the retreat of the last continental glaciers, life on Earth has become accustomed to a consistent range and variation of temperature, precipitation, sea level and polar ice patterns. Over centuries, very slow changes in weather patterns have allowed species to adapt and move over many generations. However, with more rapid changes in temperature, precipitation and severity of weather events, species will be challenged to adapt over decades and not centuries.

In Pennsylvania, climate change-related effects, warmer temperatures, changes in precipitation patterns, more frequent and intense storms, extended heat waves and longer droughts will likely affect the plants, animals and landscape of our state. The Pennsylvania Natural Heritage Program is using its knowledge of our state’s natural resources to begin to understand and identify climate change impacts on our flora and fauna, prepare for these impacts and respond to them.

Sundew (Drosera rotundifolia)
Timber rattlesnake, a species impacted by climate change
Tundra swan, photo by David Yeany.

Learning about the Science of Climate Change

A wealth of scientific information describing the factors and processes of climate change is widely available, as are predictions regarding the ways and extents to which the climate is changing. The science of climate change has grown and now includes substantial literature and studies.

Check out the following resources for more information about the science of climate change:

WPC’s Climate Change Research

Photo by Charlie EichelbergerClimate change will likely alter the distribution and abundance of plant and animal species in Pennsylvania. Some species will respond differently than others based on their biological needs, range and how dependent they are on factors affected by climate change. In Pennsylvania, we will likely have winners, species that expand their range, and losers, those whose ranges become smaller and may even be lost from the state. We may even gain species, as those currently limited to the south expand their ranges northward. Recognizing which species are more vulnerable to climate change and potential responses are important first steps in preparing for future conservation efforts.

PNHP biologists have been using a climate change vulnerability index (CCVI) developed by NatureServe to begin to understand which species in Pennsylvania are more vulnerable to climate change. We found that plants and animals with more limited dispersal and specialized habitat requirements are more vulnerable to climate change than those species that can move long distances and can be found in a variety of habitats.

The results of this project and other climate change assessments provide guidelines for updating species conservation plans and designing monitoring programs. Recognizing which species are vulnerable and the risk factors associated with vulnerability are necessary for adaptive planning.

Peatlands represent a unique group of wetlands in Pennsylvania. They are characterized as having a significant accumulation of water-logged peat. While these ecosystems occur in many regions across the globe, they are most common in cooler environments, such as at higher elevations and higher latitudes. In Pennsylvania, peatlands are found in the glaciated regions of the state and at high elevations in the mountains.

The cooler climate at high elevations provides a more boreal environment for plants and plant communities ordinarily found farther north in the United States. Many of these species are listed as rare, threatened or endangered in the state. Because of their specific temperature and water needs, peatlands will likely change in the future. The effects of climate change, such as rising temperatures and alterations in the hydrological cycle, may alter the environmental conditions that support these specialized vegetation assemblages.

To begin to understand the effects of climate change on peatlands, biologists with the Pennsylvania Natural Heritage Program have established a long-term monitoring program at 30 sites to follow target plants and plant communities to see how they change over time. We are interested in changes in plant community structure and composition, shifts in plant communities within sites, and whether some of the rarer species populations decline and what replaces them.

In addition to plants and plant communities, PNHP biologists are also interested in how other things that use peatlands will respond due to climate change. Right now, we are looking at what common bird species and insects use peatlands. Will the common species of today become less common in the future if the habitat changes? Only time will tell.

Species distribute themselves across the landscape opportunistically. They thrive where temperature, light, moisture, competition, food and other resources offer the right environment. Some species can range broadly across much of North America, while others have much more limited distribution. Pennsylvania is in a curious spot where many northern species reach their southern limit and where many southern species meet their northern limit. Although less definitive, the same is true for western and eastern-tending species as Pennsylvania picks up some species of the plains and prairie as well as those of the coastal plain.

We are interested in species populations that represent a limit or edge of their range. It has been demonstrated that the edge populations of some species are unique genetically. Adaptation to conditions different from those at the center of their range leads to physiognomic, behavioral and eventually genetic changes. Overall, this can be an advantage to a species, giving it a greater ability to adapt to climate change and environmental change, in general.

PNHP has been considering a number of edge-of-range species that are species of special concern in Pennsylvania. Our goal is to evaluate these species and their habitats, search for additional habitat and populations, and provide conservation recommendations for specific sites and populations. We are using a technique to predict appropriate habitat called climate envelope modeling.

Climate envelope models use GIS data representing geology and current and potential future climates, examining how changes in climate may affect where a given species might be able to persist in the future. The modeling process identifies new places for us to survey and gives us an indication of how widespread or confined potential habitat is for a species. By using this information when considering what the effects of rising temperatures or changes in moisture and precipitation might be, we can get an idea of how hard it may be for a species to successfully adapt and move into new areas.

Snow trillium

Snow trillium

This map shows the potential range shift of Snow Trillium under future climate scenarios (2060). Much of the suitable area in Pennsylvania for snow trillium may disappear

This map shows the potential range shift of snow trillium under future climate scenarios (2060). Much of the suitable area in Pennsylvania for snow trillium may disappear.

For More Information:

Western Pennsylvania Conservancy
800 Waterfront Drive
Pittsburgh, PA 15701