Nowhere to Go: Alpine Environments in Peril
PHOTOS: Todd Winslow Pierce/BFAG Covering just 15% of the Earth’s land surface, the alpine environment is defined both by the climate that creates it and the unique species it harbors. As the global climate warms and changes, the habitats sustained in the past are also changing. Treeline, the edge of habitat above which trees cannnot grow, is the lower boundary of the alpine. Warming temperatures and dwindling snowpacks are pushing trees to higher elevations, transforming previously open, high alpine meadows into forests. Shrinking glaciers may open new land for colonization by alpine species, but losing the water that glaciers provide could slow the process of succession that creates additional alpine meadows. The future, it seems, is uncertain for alpine plant species, treasured by botanists and nature lovers, and crucial to ptarmigan, bighorn sheep, mountain goats, rosy finches, and flightless grasshoppers.
Above: Ice cup flower, (Catophora coronata), a Chilean native with stinging hairs, in bloom at Betty Ford Alpine Gardens.
Mobile alpine species may be able to move northward in latitude if they can remain at altitudes that will l sustain them. As alpine habitats contract, however, it’s very likely that many other species will go extinct. We know that butterflies and bumblebees are moving up in elevation. What happens when these species reach alpine habitats? Will they displace alpine specialists that are already there, or create new communities with additional competition? Decades of research are needed to answer these questions.
Phenology is the study of natural seasonal events, and flowering is perhaps the simplest measure of how plants respond to climate change. Flowering phenology includes markers such as the beginning, peak, and end of flowering. These measures have been shown to differ greatly among species I response to increasing temperatures or changes in precipitation. An earlier time of first flowering doesn’t necessarily mean there will be a longer flowering duration, as the end of flowering may come earlier, or later, than it did historically. New communities of co-flowering plants are now appearing, with plants that previously did not overlap in flowering time. In all cases, the flowers that pollinators evolved to expect at particular times of their life cycles are changing.
Above: Trumpet gentian (Gentiana aucaulis) blooms throughout Betty Ford Alpine Gardens in June.
Alpine habitats can have significant topographical diversity, with slopes facing in different directions, which can result in snowbanks that can delay snowmelt and plant phenology. In some years with heavy snowpack, patches of alpine tundra won’t melt out at all. The microhabitats created by these differences in snowmelt timing help to maintain diversity in alpine habitats. At a global scale, tundra environments are diverse, with tropical alpine species perhaps being most at risk as glaciers disappear.
Scientists around the world are turning to experimental studies to gather insights into how soil, moisture, snowfall amount, snowmelt date, and warming temperatures are affecting alpine plants. Re-surveying alpine study sites and comparing data from the past with current observations can also provide information about ongoing changes.
Above: Parachute penstemon, (P. debilis) is one of the rarest plants in North America due to its limited habitat which is threatened by energy development activity.
One thing we remain certain of, however, is that climate change is disrupting and fragmenting alpine habitats and their plants. The change in plant communities is slow due to the longevity of many alpine species, which may persist for decades even of they’re no longer successfully reproducing – but its global cumulative effect is substantial.
David Inouye is Professor Emeritus in the Department of Biology at the University of Maryland, and Principal Investigator at the Rocky Mountain Biological Laboratory in Gothic, Colorado, where, for over 50 years, he has studied the ecology and interactions of wildflowers and pollinators.
Alpine Environments Are Found Everywhere in the World
What, exactly, is the alpine? Simply put, it’s the ecosystem on mopuntains and tundra that is too harsh for trees to survive. Extending from pole to pole, the alpine crosses the equator with one common ingredient: cold. While elevation is a strong determinant for alpine environments, latitude is even more important. For example, above the Arctic Circle, treeline occurs right at sea level; in the Andes of Bolivia, it rises to 17,000 feet.
Approximately 15% of the world’s total land surface area is considered alpine; just 3 percent exists in mountainous areas above treeline. Conjuring visions of wild emptiness, silence, and desolation, these seemingly bleak landscapes support almost 10,000 species of plants. The growing season can be short, with nighttime temperatures hovering at or below freezing, even in summer. Found at elevations ranging from near sea level to over 20,000 feet, alpine ecosystems exist in mountainous regions of both hemispheres including the Scottish Highlands, the Himalayas, the Rift Mountains of Africa, the Tibetan Plateau, the Causasus Mountains, the American Cordillera in both North and South America, the Pyrenees, the Swiss Alps, the southern Alps of New Zealand, and the Japanese Alps. In the United States, alpine life occurs from the northern to southern Rocky Mountains; the Sierra Nevada of California; the White Mountains in the Great Basin on the Nevada-California border; Mounts Hood and Rainier in the Cascades of Oregon and Washington; the Olympic Mountains of Washington; the northern Appalachian Mountains of New Hampshire, Maine, New York, and Vermont; Mt Washington in New Hampshire’s White Mountains; on the North Slope of Alaska and the Brooks range; in the Chugach range in southern Alaska; and in maritime coastal areas of southwestern Alaska and the Bering Sea Islands.
Arctic and Antarctic tundra occurs at high latitudes in polar regions – Alaska, Canada, Russia, Greenland, Iceland, Scandinavia, and Antarctic and subantarctic islands – where months of darkness and frigid temperatures prevail. These vast expanses support a variety of plants, including communities of sedges and heaths, dwarf shrubs, lichen and reindeer mosses, and over 400 species of flowers. Growing huddled together for protection, plants are able to withstand extreme temperatures, snow, winds, and nutrient-deficient soils. Even more astonishing is their ability to carry out photosynthesis and reproduce, often cloning copies of themselves rather than flowering.
Treeless tropical and maritime alpine regions exist too, often found in the highest mountainous regions of the world, including Papua New Guinea, Sumatra, Mexico, South America, and various countries in Africa. Hotspots of diversity, they occur where steep terrain and cold climates collide.
While shrinking rainforests and rising seas tend to dominate ecological news, alpine environments are being equally – some would argue more – compromised by the changing climate and the influence of human population. Certainly, renowned scientists and naturalists have devoted their careers to helping scientists, governmental and nongovernmental entities understand why the alpine climate zone matters.
Realizing that plants and plant diversity are the very foundation of human survival, it is imperative, then, that institutions like Betty Ford Alpine Gardens continue to advocate for the land above the trees, where tiny brilliant flowers flourish in a climate of extremes, where trees are stunted and twisted by desiccating winds, frigid temperatures, and short growing seasons, and where snow, the lifeblood of farms, ranches, communities, and cities downstream, holds ultimate control over the survival of the ecosystem.
Excerpted from On the Roof of the Rocky Mountains: The Botanical Legacy of Betty Ford Alpine Gardens, Vail’s Alpine Treasure by Sarah Chase Shaw